require 'erb' module ActionView #:nodoc: class ActionViewError < StandardError #:nodoc: end # Action View templates can be written in three 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. # If the template file has a +.rjs+ extension then it will use ActionView::Helpers::PrototypeHelper::JavaScriptGenerator. # # = 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: # # Names of all the people # <% for person in @people %> # Name: <%= person.name %>
# <% 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 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: # # <%= @page_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 # # 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. # # == 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 +.rxml+ extension. # # Here are some basic examples: # # xml.em("emphasized") # => emphasized # xml.em { xml.b("emp & bold") } # => emph & bold # xml.a("A Link", "href"=>"http://onestepback.org") # => A Link # xml.target("name"=>"compile", "option"=>"fast") # => # # 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: # #
#

David Heinemeier Hansson

#

A product of Danish Design during the Winter of '79...

#
# # 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. # # == JavaScriptGenerator # # JavaScriptGenerator templates end in +.rjs+. Unlike conventional templates which are used to # render the results of an action, these templates generate instructions on how to modify an already rendered page. This makes it easy to # modify multiple elements on your page in one declarative Ajax response. Actions with these templates are called in the background with Ajax # and make updates to the page where the request originated from. # # An instance of the JavaScriptGenerator object named +page+ is automatically made available to your template, which is implicitly wrapped in an ActionView::Helpers::PrototypeHelper#update_page block. # # When an .rjs action is called with +link_to_remote+, the generated JavaScript is automatically evaluated. Example: # # link_to_remote :url => {:action => 'delete'} # # The subsequently rendered +delete.rjs+ might look like: # # page.replace_html 'sidebar', :partial => 'sidebar' # page.remove "person-#{@person.id}" # page.visual_effect :highlight, 'user-list' # # This refreshes the sidebar, removes a person element and highlights the user list. # # See the ActionView::Helpers::PrototypeHelper::JavaScriptGenerator documentation for more details. class Base include ERB::Util attr_reader :first_render attr_accessor :base_path, :assigns, :template_extension attr_accessor :controller attr_reader :logger, :params, :request, :response, :session, :headers, :flash # Specify trim mode for the ERB compiler. Defaults to '-'. # See ERB documentation for suitable values. @@erb_trim_mode = '-' cattr_accessor :erb_trim_mode # Specify whether file modification times should be checked to see if a template needs recompilation @@cache_template_loading = false cattr_accessor :cache_template_loading # Specify whether local_assigns should be able to use string keys. # Defaults to +true+. String keys are deprecated and will be removed # shortly. @@local_assigns_support_string_keys = true cattr_accessor :local_assigns_support_string_keys @@template_handlers = {} module CompiledTemplates #:nodoc: # holds compiled template code end include CompiledTemplates # maps inline templates to their method names @@method_names = {} # map method names to their compile time @@compile_time = {} # map method names to the names passed in local assigns so far @@template_args = {} # count the number of inline templates @@inline_template_count = 0 class ObjectWrapper < Struct.new(:value) #:nodoc: end def self.load_helpers(helper_dir)#:nodoc: Dir.foreach(helper_dir) do |helper_file| next unless helper_file =~ /^([a-z][a-z_]*_helper).rb$/ require File.join(helper_dir, $1) helper_module_name = $1.camelize class_eval("include ActionView::Helpers::#{helper_module_name}") if Helpers.const_defined?(helper_module_name) end end # Register a class that knows how to handle template files with the given # extension. This can be used to implement new template types. # The constructor for the class must take the ActiveView::Base instance # as a parameter, and the class must implement a #render method that # takes the contents of the template to render as well as the Hash of # local assigns available to the template. The #render method ought to # return the rendered template as a string. def self.register_template_handler(extension, klass) @@template_handlers[extension] = klass end def initialize(base_path = nil, assigns_for_first_render = {}, controller = nil)#:nodoc: @base_path, @assigns = base_path, assigns_for_first_render @assigns_added = nil @controller = controller @logger = controller && controller.logger end # Renders the template present at template_path. If use_full_path is set to true, # it's relative to the template_root, otherwise it's absolute. The hash in local_assigns # 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 = nil # Don't read the source until we know that it is required begin render_template(template_extension, template_source, template_file_name, 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 template_path (relative to the template_root). # The hash in local_assigns is made available as local variables. def render(options = {}, old_local_assigns = {}, &block) if options.is_a?(String) render_file(options, true, old_local_assigns) elsif options == :update update_page(&block) elsif options.is_a?(Hash) options[:locals] ||= {} options[:use_full_path] = options[:use_full_path].nil? ? true : options[:use_full_path] if options[:file] render_file(options[:file], options[:use_full_path], options[:locals]) elsif options[:partial] && options[:collection] render_partial_collection(options[:partial], options[:collection], options[:spacer_template], options[:locals]) elsif options[:partial] render_partial(options[:partial], ActionView::Base::ObjectWrapper.new(options[:object]), options[:locals]) elsif options[:inline] render_template(options[:type] || :rhtml, options[:inline], nil, options[:locals] || {}) end end end # Renders the +template+ which is given as a string as either rhtml or rxml depending on template_extension. # The hash in local_assigns is made available as local variables. def render_template(template_extension, template, file_path = nil, local_assigns = {}) if handler = @@template_handlers[template_extension] template ||= read_template_file(file_path, template_extension) # Make sure that a lazyily-read template is loaded. delegate_render(handler, template, local_assigns) else compile_and_render_template(template_extension, template, file_path, local_assigns) end end # Render the provided template with the given local assigns. If the template has not been rendered with the provided # local assigns yet, or if the template has been updated on disk, then the template will be compiled to a method. # # Either, but not both, of template and file_path may be nil. If file_path is given, the template # will only be read if it has to be compiled. # def compile_and_render_template(extension, template = nil, file_path = nil, local_assigns = {}) # compile the given template, if necessary if compile_template?(template, file_path, local_assigns) template ||= read_template_file(file_path, extension) compile_template(extension, template, file_path, local_assigns) end # Get the method name for this template and run it method_name = @@method_names[file_path || template] evaluate_assigns local_assigns = local_assigns.symbolize_keys if @@local_assigns_support_string_keys send(method_name, local_assigns) do |*name| instance_variable_get "@content_for_#{name.first || 'layout'}" end end def pick_template_extension(template_path)#:nodoc: if match = delegate_template_exists?(template_path) match.first elsif erb_template_exists?(template_path): 'rhtml' elsif builder_template_exists?(template_path): 'rxml' elsif javascript_template_exists?(template_path): 'rjs' else raise ActionViewError, "No rhtml, rxml, rjs or delegate template found for #{template_path}" end end def delegate_template_exists?(template_path)#:nodoc: @@template_handlers.find { |k,| template_exists?(template_path, k) } 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 javascript_template_exists?(template_path)#:nodoc: template_exists?(template_path, :rjs) end def file_exists?(template_path)#:nodoc: %w(erb builder javascript delegate).any? do |template_type| send("#{template_type}_template_exists?", template_path) end 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) file_path = full_template_path(template_path, extension) @@method_names.has_key?(file_path) || FileTest.exists?(file_path) end # This method reads a template file. def read_template_file(template_path, extension) File.read(template_path) end def evaluate_assigns unless @assigns_added assign_variables_from_controller @assigns_added = true end end def delegate_render(handler, template, local_assigns) handler.new(self).render(template, local_assigns) end def assign_variables_from_controller @assigns.each { |key, value| instance_variable_set("@#{key}", value) } end # Return true if the given template was compiled for a superset of the keys in local_assigns def supports_local_assigns?(render_symbol, local_assigns) local_assigns.empty? || ((args = @@template_args[render_symbol]) && local_assigns.all? { |k,_| args.has_key?(k) }) end # Check whether compilation is necessary. # Compile if the inline template or file has not been compiled yet. # Or if local_assigns has a new key, which isn't supported by the compiled code yet. # Or if the file has changed on disk and checking file mods hasn't been disabled. def compile_template?(template, file_name, local_assigns) method_key = file_name || template render_symbol = @@method_names[method_key] if @@compile_time[render_symbol] && supports_local_assigns?(render_symbol, local_assigns) if file_name && !@@cache_template_loading @@compile_time[render_symbol] < File.mtime(file_name) end else true end end # Create source code for given template def create_template_source(extension, template, render_symbol, locals) if template_requires_setup?(extension) body = case extension.to_sym when :rxml "xml = Builder::XmlMarkup.new(:indent => 2)\n" + "@controller.headers['Content-Type'] ||= 'text/xml'\n" + template when :rjs "@controller.headers['Content-Type'] ||= 'text/javascript'\n" + "update_page do |page|\n#{template}\nend" end else body = ERB.new(template, nil, @@erb_trim_mode).src end @@template_args[render_symbol] ||= {} locals_keys = @@template_args[render_symbol].keys | locals @@template_args[render_symbol] = locals_keys.inject({}) { |h, k| h[k] = true; h } locals_code = "" locals_keys.each do |key| locals_code << "#{key} = local_assigns[:#{key}] if local_assigns.has_key?(:#{key})\n" end "def #{render_symbol}(local_assigns)\n#{locals_code}#{body}\nend" end def template_requires_setup?(extension) templates_requiring_setup.include? extension.to_s end def templates_requiring_setup %w(rxml rjs) end def assign_method_name(extension, template, file_name) method_name = '_run_' method_name << "#{extension}_" if extension if file_name file_path = File.expand_path(file_name) base_path = File.expand_path(@base_path) i = file_path.index(base_path) l = base_path.length method_name_file_part = i ? file_path[i+l+1,file_path.length-l-1] : file_path.clone method_name_file_part.sub!(/\.r(html|xml|js)$/,'') method_name_file_part.tr!('/:-', '_') method_name_file_part.gsub!(/[^a-zA-Z0-9_]/){|s| s[0].to_s} method_name += method_name_file_part else @@inline_template_count += 1 method_name << @@inline_template_count.to_s end @@method_names[file_name || template] = method_name.intern end def compile_template(extension, template, file_name, local_assigns) method_key = file_name || template render_symbol = @@method_names[method_key] || assign_method_name(extension, template, file_name) render_source = create_template_source(extension, template, render_symbol, local_assigns.keys) line_offset = @@template_args[render_symbol].size if extension case extension.to_sym when :rxml, :rjs line_offset += 2 end end begin unless file_name.blank? CompiledTemplates.module_eval(render_source, file_name, -line_offset) else CompiledTemplates.module_eval(render_source, 'compiled-template', -line_offset) end rescue Object => e if logger logger.debug "ERROR: compiling #{render_symbol} RAISED #{e}" logger.debug "Function body: #{render_source}" logger.debug "Backtrace: #{e.backtrace.join("\n")}" end raise TemplateError.new(@base_path, method_key, @assigns, template, e) end @@compile_time[render_symbol] = Time.now # logger.debug "Compiled template #{method_key}\n ==> #{render_symbol}" if logger end end end require 'action_view/template_error'