diff options
Diffstat (limited to 'actionpack/lib/action_view/base.rb')
| -rw-r--r-- | actionpack/lib/action_view/base.rb | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/actionpack/lib/action_view/base.rb b/actionpack/lib/action_view/base.rb new file mode 100644 index 0000000000..84c8040760 --- /dev/null +++ b/actionpack/lib/action_view/base.rb @@ -0,0 +1,264 @@ +require 'erb' + +module ActionView #:nodoc: + class ActionViewError < StandardError #:nodoc: + end + + # Action View templates can be written in two ways. If the template file has a +.rhtml+ extension then it uses a mixture of ERb + # (included in Ruby) and HTML. If the template file has a +.rxml+ extension then Jim Weirich's Builder::XmlMarkup library is used. + # + # = ERb + # + # You trigger ERb by using embeddings such as <% %> and <%= %>. The difference is whether you want output or not. Consider the + # following loop for names: + # + # <b>Names of all the people</b> + # <% for person in @people %> + # Name: <%= person.name %><br/> + # <% end %> + # + # 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. Regular output functions like print or puts won't work with ERb templates. So this would be wrong: + # + # Hi, Mr. <% puts "Frodo" %> + # + # (If you absolutely must write from within a function, you can use the TextHelper#concat) + # + # == Using sub templates + # + # Using sub templates allows you to sidestep tedious replication and extract common display structures in shared templates. The + # classic example is the use of a header and footer (even though the Action Pack-way would be to use Layouts): + # + # <%= render "shared/header" %> + # Something really specific and terrific + # <%= render "shared/footer" %> + # + # As you see, we use the output embeddings for the render methods. The render call itself will just return a string holding the + # result of the rendering. The output embedding writes it to the current template. + # + # But you don't have to restrict yourself to static includes. Templates can share variables amongst themselves by using instance + # variables defined in using the regular embedding tags. Like this: + # + # <% @page_title = "A Wonderful Hello" %> + # <%= render "shared/header" %> + # + # Now the header can pick up on the @page_title variable and use it for outputting a title tag: + # + # <title><%= @page_title %></title> + # + # == Passing local variables to sub templates + # + # You can pass local variables to sub templates by using a hash with the variable names as keys and the objects as values: + # + # <%= render "shared/header", { "headline" => "Welcome", "person" => person } %> + # + # These can now be accessed in shared/header with: + # + # Headline: <%= headline %> + # First name: <%= person.first_name %> + # + # == Template caching + # + # The parsing of ERb templates are cached by default, but the reading of them are not. This means that the application by default + # will reflect changes to the templates immediatly. If you'd like to sacrifice that immediacy for the speed gain given by also + # caching the loading of templates (reading from the file systen), you can turn that on with + # <tt>ActionView::Base.cache_template_loading = true</tt>. + # + # == Builder + # + # Builder templates are a more programatic alternative to ERb. They are especially useful for generating XML content. An +XmlMarkup+ object + # named +xml+ is automatically made available to templates with a +.rxml+ extension. + # + # Here are some basic examples: + # + # xml.em("emphasized") # => <em>emphasized</em> + # xml.em { xml.b("emp & bold") } # => <em><b>emph & bold</b></em> + # xml.a("A Link", "href"=>"http://onestepback.org") # => <a href="http://onestepback.org">A Link</a> + # xm.target("name"=>"compile", "option"=>"fast") # => <target option="fast" name="compile"\> + # # NOTE: order of attributes is not specified. + # + # Any method with a block will be treated as an XML markup tag with nested markup in the block. For example, the following: + # + # xml.div { + # xml.h1(@person.name) + # xml.p(@person.bio) + # } + # + # would produce something like: + # + # <div> + # <h1>David Heinemeier Hansson</h1> + # <p>A product of Danish Design during the Winter of '79...</p> + # </div> + # + # A full-length RSS example actually used on Basecamp: + # + # xml.rss("version" => "2.0", "xmlns:dc" => "http://purl.org/dc/elements/1.1/") do + # xml.channel do + # xml.title(@feed_title) + # xml.link(@url) + # xml.description "Basecamp: Recent items" + # xml.language "en-us" + # xml.ttl "40" + # + # for item in @recent_items + # xml.item do + # xml.title(item_title(item)) + # xml.description(item_description(item)) if item_description(item) + # xml.pubDate(item_pubDate(item)) + # xml.guid(@person.firm.account.url + @recent_items.url(item)) + # xml.link(@person.firm.account.url + @recent_items.url(item)) + # + # xml.tag!("dc:creator", item.author_name) if item_has_creator?(item) + # end + # end + # end + # end + # + # More builder documentation can be found at http://builder.rubyforge.org. + class Base + include ERB::Util + + attr_reader :first_render + attr_accessor :base_path, :assigns, :template_extension + attr_accessor :controller + + # Turn on to cache the reading of templates from the file system. Doing so means that you have to restart the server + # when changing templates, but that rendering will be faster. + @@cache_template_loading = false + cattr_accessor :cache_template_loading + + @@compiled_erb_templates = {} + @@loaded_templates = {} + + def self.load_helpers(helper_dir)#:nodoc: + Dir.foreach(helper_dir) do |helper_file| + next unless helper_file =~ /_helper.rb$/ + require helper_dir + helper_file + helper_module_name = helper_file.capitalize.gsub(/_([a-z])/) { |m| $1.capitalize }[0..-4] + + class_eval("include ActionView::Helpers::#{helper_module_name}") if Helpers.const_defined?(helper_module_name) + end + end + + def self.controller_delegate(*methods) + methods.flatten.each do |method| + class_eval <<-end_eval + def #{method}(*args, &block) + controller.send(%(#{method}), *args, &block) + end + end_eval + end + end + + def initialize(base_path = nil, assigns_for_first_render = {}, controller = nil)#:nodoc: + @base_path, @assigns = base_path, assigns_for_first_render + @controller = controller + end + + # Renders the template present at <tt>template_path</tt>. If <tt>use_full_path</tt> is set to true, + # it's relative to the template_root, otherwise it's absolute. The hash in <tt>local_assigns</tt> + # is made available as local variables. + def render_file(template_path, use_full_path = true, local_assigns = {}) + @first_render = template_path if @first_render.nil? + + if use_full_path + template_extension = pick_template_extension(template_path) + template_file_name = full_template_path(template_path, template_extension) + else + template_file_name = template_path + template_extension = template_path.split(".").last + end + + template_source = read_template_file(template_file_name) + + begin + render_template(template_extension, template_source, local_assigns) + rescue Exception => e + if TemplateError === e + e.sub_template_of(template_file_name) + raise e + else + raise TemplateError.new(@base_path, template_file_name, @assigns, template_source, e) + end + end + end + + # Renders the template present at <tt>template_path</tt> (relative to the template_root). + # The hash in <tt>local_assigns</tt> is made available as local variables. + def render(template_path, local_assigns = {}) + render_file(template_path, true, local_assigns) + end + + # Renders the +template+ which is given as a string as either rhtml or rxml depending on <tt>template_extension</tt>. + # The hash in <tt>local_assigns</tt> is made available as local variables. + def render_template(template_extension, template, local_assigns = {}) + b = binding + local_assigns.each { |key, value| eval "#{key} = local_assigns[\"#{key}\"]", b } + @assigns.each { |key, value| instance_variable_set "@#{key}", value } + xml = Builder::XmlMarkup.new(:indent => 2) + + send(pick_rendering_method(template_extension), template, binding) + end + + def pick_template_extension(template_path)#:nodoc: + if erb_template_exists?(template_path) + "rhtml" + elsif builder_template_exists?(template_path) + "rxml" + else + raise ActionViewError, "No rhtml or rxml template found for #{template_path}" + end + end + + def pick_rendering_method(template_extension)#:nodoc: + (template_extension == "rxml" ? "rxml" : "rhtml") + "_render" + end + + def erb_template_exists?(template_path)#:nodoc: + template_exists?(template_path, "rhtml") + end + + def builder_template_exists?(template_path)#:nodoc: + template_exists?(template_path, "rxml") + end + + def file_exists?(template_path)#:nodoc: + erb_template_exists?(template_path) || builder_template_exists?(template_path) + end + + # Returns true is the file may be rendered implicitly. + def file_public?(template_path)#:nodoc: + template_path.split("/").last[0,1] != "_" + end + + private + def full_template_path(template_path, extension) + "#{@base_path}/#{template_path}.#{extension}" + end + + def template_exists?(template_path, extension) + FileTest.exists?(full_template_path(template_path, extension)) + end + + def read_template_file(template_path) + unless cache_template_loading && @@loaded_templates[template_path] + @@loaded_templates[template_path] = File.read(template_path) + end + + @@loaded_templates[template_path] + end + + def rhtml_render(template, binding) + @@compiled_erb_templates[template] ||= ERB.new(template) + @@compiled_erb_templates[template].result(binding) + end + + def rxml_render(template, binding) + @controller.headers["Content-Type"] ||= 'text/xml' + eval(template, binding) + end + end +end + +require 'action_view/template_error' |