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Diffstat (limited to 'actionpack/lib/action_view/renderer/partial_renderer.rb')
| -rw-r--r-- | actionpack/lib/action_view/renderer/partial_renderer.rb | 217 |
1 files changed, 216 insertions, 1 deletions
diff --git a/actionpack/lib/action_view/renderer/partial_renderer.rb b/actionpack/lib/action_view/renderer/partial_renderer.rb index 10cd37d56f..83efc95f39 100644 --- a/actionpack/lib/action_view/renderer/partial_renderer.rb +++ b/actionpack/lib/action_view/renderer/partial_renderer.rb @@ -1,8 +1,223 @@ +require 'active_support/core_ext/object/blank' + module ActionView + # = Action View Partials + # + # 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.html.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 } %> + # + # <% @advertisements.each do |ad| %> + # <%= render :partial => "ad", :locals => { :ad => ad } %> + # <% end %> + # + # This would first render "advertiser/_account.html.erb" with @buyer passed in as the local variable +account+, then + # render "advertiser/_ad.html.erb" and pass the local variable +ad+ to the template for display. + # + # == 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 + # + # <%= render :partial => "contract" %> + # + # within contract we'll get <tt>@contract</tt> in the local variable +contract+, as if we had written + # + # <%= render :partial => "contract", :locals => { :contract => @contract } %> + # + # With the <tt>:as</tt> option we can specify a different name for said local variable. For example, if we + # wanted it to be +agreement+ instead of +contract+ we'd do: + # + # <%= render :partial => "contract", :as => 'agreement' %> + # + # 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. + # + # Revisiting a previous example we could have written this code: + # + # <%= render :partial => "account", :object => @buyer %> + # + # <% @advertisements.each do |ad| %> + # <%= render :partial => "ad", :object => ad %> + # <% end %> + # + # The <tt>:object</tt> and <tt>:as</tt> options can be used together. + # + # == 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.html.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+. + # + # The <tt>:as</tt> option may be used when rendering partials. + # + # You can specify a partial to be rendered between elements via the <tt>:spacer_template</tt> option. + # The following example will render <tt>advertiser/_ad_divider.html.erb</tt> between each ad partial: + # + # <%= render :partial => "ad", :collection => @advertisements, :spacer_template => "ad_divider" %> + # + # If the given <tt>:collection</tt> is nil or empty, <tt>render</tt> will return nil. This will allow you + # to specify a text which will displayed instead by using this form: + # + # <%= render(:partial => "ad", :collection => @advertisements) || "There's no ad to be displayed" %> + # + # 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.html.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 => @account} %> + # <%= 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 &> + # <div id="administrator"> + # Budget: $<%= user.budget %> + # <%= yield %> + # </div> + # + # <%# app/views/users/_editor.html.erb &> + # <div id="editor"> + # Deadline: <%= user.deadline %> + # <%= yield %> + # </div> + # + # ...this will return: + # + # Here's the administrator: + # <div id="administrator"> + # Budget: $<%= user.budget %> + # Name: <%= user.name %> + # </div> + # + # Here's the editor: + # <div id="editor"> + # Deadline: <%= user.deadline %> + # Name: <%= user.name %> + # </div> + # + # 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: + # + # <div id="administrator"> + # Budget: $<%= user.budget %> + # Title: <%= chief.name %> + # </div> + # + # As you can see, the <tt>:locals</tt> 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 &> + # <div class="user"> + # Budget: $<%= user.budget %> + # <%= yield user %> + # </div> + # + # <%# 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 &> + # <div class="user"> + # <%= yield user, :header %> + # Budget: $<%= user.budget %> + # <%= yield user, :footer %> + # </div> + # + # <%# 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 %> class PartialRenderer < AbstractRenderer #:nodoc: PARTIAL_NAMES = Hash.new {|h,k| h[k] = {} } - def initialize(view) + def initialize(view, *) super @partial_names = PARTIAL_NAMES[@view.controller.class.name] end |