module ActionView # There's also a convenience method for rendering sub templates within the current controller that depends on a # single object (we call this kind of sub templates for partials). It relies on the fact that partials should # follow the naming convention of being prefixed with an underscore -- as to separate them from regular # templates that could be rendered on their own. # # In a template for Advertiser#account: # # <%= render :partial => "account" %> # # This would render "advertiser/_account.erb" and pass the instance variable @account in as a local variable # +account+ to the template for display. # # In another template for Advertiser#buy, we could have: # # <%= render :partial => "account", :locals => { :account => @buyer } %> # # <% for ad in @advertisements %> # <%= render :partial => "ad", :locals => { :ad => ad } %> # <% end %> # # This would first render "advertiser/_account.erb" with @buyer passed in as the local variable +account+, then # render "advertiser/_ad.erb" and pass the local variable +ad+ to the template for display. # # == Rendering a collection of partials # # 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 in "Using partials" can be rewritten with a single line: # # <%= render :partial => "ad", :collection => @advertisements %> # # This will render "advertiser/_ad.erb" and pass the local variable +ad+ to the template for display. An # iteration counter will automatically be made available to the template with a name of the form # +partial_name_counter+. In the case of the example above, the template would be fed +ad_counter+. # # NOTE: Due to backwards compatibility concerns, the collection can't be one of hashes. Normally you'd also # just keep domain objects, like Active Records, in there. # # == Rendering shared partials # # Two controllers can share a set of partials and render them like this: # # <%= render :partial => "advertisement/ad", :locals => { :ad => @advertisement } %> # # This will render the partial "advertisement/_ad.erb" regardless of which controller this is being called from. # # == Rendering objects with the RecordIdentifier # # Instead of explicitly naming the location of a partial, you can also let the RecordIdentifier do the work if # you're following its conventions for RecordIdentifier#partial_path. Examples: # # # @account is an Account instance, so it uses the RecordIdentifier to replace # # <%= render :partial => "accounts/account", :locals => { :account => @buyer } %> # <%= render :partial => @account %> # # # @posts is an array of Post instances, so it uses the RecordIdentifier to replace # # <%= render :partial => "posts/post", :collection => @posts %> # <%= render :partial => @posts %> # # == Rendering the default case # # If you're not going to be using any of the options like collections or layouts, you can also use the short-hand # defaults of render to render partials. Examples: # # # Instead of <%= render :partial => "account" %> # <%= render "account" %> # # # Instead of <%= render :partial => "account", :locals => { :account => @buyer } %> # <%= render "account", :account => @buyer %> # # # @account is an Account instance, so it uses the RecordIdentifier to replace # # <%= render :partial => "accounts/account", :locals => { :account => @account } %> # <%= render(@account) %> # # # @posts is an array of Post instances, so it uses the RecordIdentifier to replace # # <%= render :partial => "posts/post", :collection => @posts %> # <%= render(@posts) %> # # == Rendering partials with 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. Imagine a list with two types # of users: # # <%# app/views/users/index.html.erb &> # Here's the administrator: # <%= render :partial => "user", :layout => "administrator", :locals => { :user => administrator } %> # # Here's the editor: # <%= render :partial => "user", :layout => "editor", :locals => { :user => editor } %> # # <%# app/views/users/_user.html.erb &> # Name: <%= user.name %> # # <%# app/views/users/_administrator.html.erb &> #
# Budget: $<%= user.budget %> # <%= yield %> #
# # <%# app/views/users/_editor.html.erb &> #
# Deadline: <%= user.deadline %> # <%= yield %> #
# # ...this will return: # # Here's the administrator: #
# Budget: $<%= user.budget %> # Name: <%= user.name %> #
# # Here's the editor: #
# Deadline: <%= user.deadline %> # Name: <%= user.name %> #
# # You can also apply a layout to a block within any template: # # <%# app/views/users/_chief.html.erb &> # <% render(:layout => "administrator", :locals => { :user => chief }) do %> # Title: <%= chief.title %> # <% end %> # # ...this will return: # #
# Budget: $<%= user.budget %> # Title: <%= chief.name %> #
# # As you can see, the :locals hash is shared between both the partial and its layout. # # If you pass arguments to "yield" then this will be passed to the block. One way to use this is to pass # an array to layout and treat it as an enumerable. # # <%# app/views/users/_user.html.erb &> #
# Budget: $<%= user.budget %> # <%= yield user %> #
# # <%# app/views/users/index.html.erb &> # <% render :layout => @users do |user| %> # Title: <%= user.title %> # <% end %> # # This will render the layout for each user and yield to the block, passing the user, each time. # # You can also yield multiple times in one layout and use block arguments to differentiate the sections. # # <%# app/views/users/_user.html.erb &> #
# <%= yield user, :header %> # Budget: $<%= user.budget %> # <%= yield user, :footer %> #
# # <%# app/views/users/index.html.erb &> # <% render :layout => @users do |user, section| %> # <%- case section when :header -%> # Title: <%= user.title %> # <%- when :footer -%> # Deadline: <%= user.deadline %> # <%- end -%> # <% end %> module Partials extend ActiveSupport::Memoizable def _render_partial(options = {}) #:nodoc: options[:locals] ||= {} case path = partial = options[:partial] when *_array_like_objects return _render_partial_collection(partial, options) else if partial.is_a?(ActionView::Helpers::FormBuilder) path = partial.class.to_s.demodulize.underscore.sub(/_builder$/, '') options[:locals].merge!(path.to_sym => partial) elsif !partial.is_a?(String) options[:object] = object = partial path = ActionController::RecordIdentifier.partial_path(object, controller_path) end _, _, prefix, object = parts = partial_parts(path, options) parts[1] = {:formats => parts[1]} template = find_by_parts(*parts) _render_partial_object(template, options, (object unless object == true)) end end private def partial_parts(name, options) segments = name.split("/") parts = segments.pop.split(".") case parts.size when 1 parts when 2, 3 extension = parts.delete_at(1).to_sym if formats.include?(extension) self.formats.replace [extension] end parts.pop if parts.size == 2 end path = parts.join(".") prefix = segments[0..-1].join("/") prefix = prefix.blank? ? controller_path : prefix parts = [path, formats, prefix] parts.push options[:object] || true end def _render_partial_with_block(layout, block, options) @_proc_for_layout = block concat(_render_partial(options.merge(:partial => layout))) ensure @_proc_for_layout = nil end def _render_partial_with_layout(layout, options) if layout prefix = controller && !layout.include?("/") ? controller.controller_path : nil layout = find_by_parts(layout, {:formats => formats}, prefix, true) end content = _render_partial(options) return _render_content_with_layout(content, layout, options[:locals]) end def _deprecated_ivar_assign(template) if respond_to?(:controller) ivar = :"@#{template.variable_name}" object = if controller.instance_variable_defined?(ivar) ActiveSupport::Deprecation::DeprecatedObjectProxy.new( controller.instance_variable_get(ivar), "#{ivar} will no longer be implicitly assigned to #{template.variable_name}") end end end def _render_partial_with_block(layout, block, options) @_proc_for_layout = block concat(_render_partial(options.merge(:partial => layout))) ensure @_proc_for_layout = nil end def _render_partial_with_layout(layout, options) if layout prefix = controller && !layout.include?("/") ? controller.controller_path : nil layout = find_by_parts(layout, {:formats => formats}, prefix, true) end content = _render_partial(options) return _render_content_with_layout(content, layout, options[:locals]) end def _deprecated_ivar_assign(template) if respond_to?(:controller) ivar = :"@#{template.variable_name}" object = if controller.instance_variable_defined?(ivar) ActiveSupport::Deprecation::DeprecatedObjectProxy.new( controller.instance_variable_get(ivar), "#{ivar} will no longer be implicitly assigned to #{template.variable_name}") end end end def _array_like_objects array_like = [Array] if defined?(ActiveRecord) array_like.push(ActiveRecord::Associations::AssociationCollection, ActiveRecord::NamedScope::Scope) end array_like end def _render_partial_object(template, options, object = nil) if options.key?(:collection) _render_partial_collection(options.delete(:collection), options, template) else locals = (options[:locals] ||= {}) object ||= locals[:object] || locals[template.variable_name] _set_locals(object, locals, template, options) _render_template(template, locals) end end def _set_locals(object, locals, template, options) object ||= _deprecated_ivar_assign(template) locals[:object] = locals[template.variable_name] = object locals[options[:as]] = object if options[:as] end def _render_partial_collection(collection, options = {}, passed_template = nil) #:nodoc: return nil if collection.blank? spacer = options[:spacer_template] ? _render_partial(:partial => options[:spacer_template]) : '' locals = (options[:locals] ||= {}) index, @_partial_path = 0, nil collection.map do |object| template = passed_template || begin _partial_path = ActionController::RecordIdentifier.partial_path(object, controller_path) template = _pick_partial_template(_partial_path) end _set_locals(object, locals, template, options) locals[template.counter_name] = index index += 1 _render_template(template, locals) end.join(spacer) end def _pick_partial_template(partial_path) #:nodoc: prefix = controller_path unless partial_path.include?('/') find_by_parts(partial_path, {:formats => formats}, prefix, true) end memoize :_pick_partial_template end end