module ActionView #:nodoc: class ActionViewError < StandardError #:nodoc: end # Action View templates can be written in three ways. If the template file has a +.erb+ (or +.rhtml+) extension then it uses a mixture of ERb # (included in Ruby) and HTML. If the template file has a +.builder+ (or +.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 <%= %> tag set is used when you want output. 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 # # <%- and -%> suppress leading and trailing whitespace, including the trailing newline, and can be used interchangeably with <% and %>. # # == 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 %> # # If you need to find out whether a certain local variable has been assigned a value in a particular render call, # you need to use the following pattern: # # <% if local_assigns.has_key? :headline %> # Headline: <%= headline %> # <% end %> # # Testing using defined? headline will not work. This is an implementation restriction. # # == 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 +.builder+ extension. # # Here are some basic examples: # # xml.em("emphasized") # => emphasized # xml.em { xml.b("emph & 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::GeneratorMethods documentation for more details. class Base include ERB::Util attr_reader :finder attr_accessor :base_path, :assigns, :template_extension, :first_render attr_accessor :controller attr_reader :logger, :response, :headers attr_internal :cookies, :flash, :headers, :params, :request, :response, :session attr_writer :template_format attr_accessor :current_render_extension # 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 file extension lookup should be cached, and whether template base path lookup should be cached. # Should be +false+ for development environments. Defaults to +true+. @@cache_template_extensions = true cattr_accessor :cache_template_extensions # Specify whether RJS responses should be wrapped in a try/catch block # that alert()s the caught exception (and then re-raises it). @@debug_rjs = false cattr_accessor :debug_rjs @@erb_variable = '_erbout' cattr_accessor :erb_variable delegate :request_forgery_protection_token, :to => :controller @@template_handlers = HashWithIndifferentAccess.new module CompiledTemplates #:nodoc: # holds compiled template code end include CompiledTemplates # Maps inline templates to their method names cattr_accessor :method_names @@method_names = {} # Map method names to the names passed in local assigns so far @@template_args = {} # Cache public asset paths cattr_reader :computed_public_paths @@computed_public_paths = {} @@template_handlers = {} @@default_template_handlers = nil class ObjectWrapper < Struct.new(:value) #:nodoc: end def self.load_helpers #:nodoc: Dir.entries("#{File.dirname(__FILE__)}/helpers").sort.each do |file| next unless file =~ /^([a-z][a-z_]*_helper).rb$/ require "action_view/helpers/#{$1}" helper_module_name = $1.camelize if Helpers.const_defined?(helper_module_name) include Helpers.const_get(helper_module_name) end 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.to_sym] = klass TemplateFinder.update_extension_cache_for(extension.to_s) end def self.template_handler_extensions @@template_handlers.keys.map(&:to_s).sort end def self.register_default_template_handler(extension, klass) register_template_handler(extension, klass) @@default_template_handlers = klass end def self.handler_class_for_extension(extension) (extension && @@template_handlers[extension.to_sym]) || @@default_template_handlers end register_default_template_handler :erb, TemplateHandlers::ERB register_template_handler :rjs, TemplateHandlers::RJS register_template_handler :builder, TemplateHandlers::Builder # TODO: Depreciate old template extensions register_template_handler :rhtml, TemplateHandlers::ERB register_template_handler :rxml, TemplateHandlers::Builder def initialize(view_paths = [], assigns_for_first_render = {}, controller = nil)#:nodoc: @assigns = assigns_for_first_render @assigns_added = nil @controller = controller @logger = controller && controller.logger @finder = TemplateFinder.new(self, view_paths) end # Renders the template present at template_path. If use_full_path is set to true, # it's relative to the view_paths array, 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 = {}) #:nodoc: if defined?(ActionMailer) && defined?(ActionMailer::Base) && controller.is_a?(ActionMailer::Base) && !template_path.include?("/") raise ActionViewError, <<-END_ERROR Due to changes in ActionMailer, you need to provide the mailer_name along with the template name. render "user_mailer/signup" render :file => "user_mailer/signup" If you are rendering a subtemplate, you must now use controller-like partial syntax: render :partial => 'signup' # no mailer_name necessary END_ERROR end template = Template.new(self, template_path, use_full_path, local_assigns) begin render_template(template) rescue Exception => e if TemplateError === e e.sub_template_of(template.filename) raise e else raise TemplateError.new(template, @assigns, e) end end end # Renders the template present at template_path (relative to the view_paths array). # The hash in local_assigns is made available as local variables. def render(options = {}, old_local_assigns = {}, &block) #:nodoc: if options.is_a?(String) render_file(options, true, old_local_assigns) elsif options == :update update_page(&block) elsif options.is_a?(Hash) options = options.reverse_merge(:locals => {}, :use_full_path => true) if options[:layout] path, partial_name = partial_pieces(options.delete(:layout)) if block_given? wrap_content_for_layout capture(&block) do concat(render(options.merge(:partial => "#{path}/#{partial_name}")), block.binding) end else wrap_content_for_layout render(options) do render(options.merge(:partial => "#{path}/#{partial_name}")) end end elsif 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] template = Template.new(self, options[:inline], false, options[:locals], true, options[:type]) render_template(template) end end end # Renders the +template+ which is given as a string as either erb or builder depending on template_extension. # The hash in local_assigns is made available as local variables. def render_template(template) #:nodoc: handler = template.handler @current_render_extension = template.extension if handler.compilable? compile_and_render_template(handler, template) else handler.render(template.source, template.locals) end end # Returns true is the file may be rendered implicitly. def file_public?(template_path)#:nodoc: template_path.split('/').last[0,1] != '_' end # symbolized version of the :format parameter of the request, or :html by default. def template_format return @template_format if @template_format format = controller && controller.respond_to?(:request) && controller.request.parameters[:format] @template_format = format.blank? ? :html : format.to_sym end private def wrap_content_for_layout(content) original_content_for_layout = @content_for_layout @content_for_layout = content returning(yield) { @content_for_layout = original_content_for_layout } end # Evaluate the local assigns and pushes them to the view. def evaluate_assigns unless @assigns_added assign_variables_from_controller @assigns_added = true end end # Assigns instance variables from the controller to the view. def assign_variables_from_controller @assigns.each { |key, value| instance_variable_set("@#{key}", value) } 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(handler, template) #:nodoc: # compile the given template, if necessary handler.compile_template(template) # Get the method name for this template and run it method_name = @@method_names[template.method_key] evaluate_assigns send(method_name, template.locals) do |*name| instance_variable_get "@content_for_#{name.first || 'layout'}" end end end end