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https://github.com/rails/rails.git
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475 lines
16 KiB
Ruby
475 lines
16 KiB
Ruby
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module ActionView
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# = Action View Partials
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#
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# There's also a convenience method for rendering sub templates within the current controller that depends on a
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# single object (we call this kind of sub templates for partials). It relies on the fact that partials should
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# follow the naming convention of being prefixed with an underscore -- as to separate them from regular
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# templates that could be rendered on their own.
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#
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# In a template for Advertiser#account:
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#
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# <%= render :partial => "account" %>
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#
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# This would render "advertiser/_account.html.erb".
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#
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# In another template for Advertiser#buy, we could have:
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#
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# <%= render :partial => "account", :locals => { :account => @buyer } %>
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#
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# <% @advertisements.each do |ad| %>
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# <%= render :partial => "ad", :locals => { :ad => ad } %>
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# <% end %>
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#
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# This would first render "advertiser/_account.html.erb" with @buyer passed in as the local variable +account+, then
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# render "advertiser/_ad.html.erb" and pass the local variable +ad+ to the template for display.
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#
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# == The :as and :object options
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#
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# By default <tt>ActionView::PartialRenderer</tt> doesn't have any local variables.
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# The <tt>:object</tt> option can be used to pass an object to the partial. For instance:
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#
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# <%= render :partial => "account", :object => @buyer %>
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#
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# would provide the <tt>@buyer</tt> object to the partial, available under the local variable +account+ and is
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# equivalent to:
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#
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# <%= render :partial => "account", :locals => { :account => @buyer } %>
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#
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# With the <tt>:as</tt> option we can specify a different name for said local variable. For example, if we
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# wanted it to be +user+ instead of +account+ we'd do:
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#
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# <%= render :partial => "account", :object => @buyer, :as => 'user' %>
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#
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# This is equivalent to
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#
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# <%= render :partial => "account", :locals => { :user => @buyer } %>
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#
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# == Rendering a collection of partials
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#
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# The example of partial use describes a familiar pattern where a template needs to iterate over an array and
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# render a sub template for each of the elements. This pattern has been implemented as a single method that
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# accepts an array and renders a partial by the same name as the elements contained within. So the three-lined
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# example in "Using partials" can be rewritten with a single line:
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#
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# <%= render :partial => "ad", :collection => @advertisements %>
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#
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# This will render "advertiser/_ad.html.erb" and pass the local variable +ad+ to the template for display. An
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# iteration counter will automatically be made available to the template with a name of the form
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# +partial_name_counter+. In the case of the example above, the template would be fed +ad_counter+.
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#
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# The <tt>:as</tt> option may be used when rendering partials.
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#
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# You can specify a partial to be rendered between elements via the <tt>:spacer_template</tt> option.
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# The following example will render <tt>advertiser/_ad_divider.html.erb</tt> between each ad partial:
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#
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# <%= render :partial => "ad", :collection => @advertisements, :spacer_template => "ad_divider" %>
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#
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# If the given <tt>:collection</tt> is nil or empty, <tt>render</tt> will return nil. This will allow you
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# to specify a text which will displayed instead by using this form:
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#
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# <%= render(:partial => "ad", :collection => @advertisements) || "There's no ad to be displayed" %>
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#
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# NOTE: Due to backwards compatibility concerns, the collection can't be one of hashes. Normally you'd also
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# just keep domain objects, like Active Records, in there.
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#
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# == Rendering shared partials
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#
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# Two controllers can share a set of partials and render them like this:
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#
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# <%= render :partial => "advertisement/ad", :locals => { :ad => @advertisement } %>
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#
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# This will render the partial "advertisement/_ad.html.erb" regardless of which controller this is being called from.
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#
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# == Rendering objects that respond to `to_partial_path`
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#
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# Instead of explicitly naming the location of a partial, you can also let PartialRenderer do the work
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# and pick the proper path by checking `to_partial_path` method.
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#
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# # @account.to_partial_path returns 'accounts/account', so it can be used to replace:
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# # <%= render :partial => "accounts/account", :locals => { :account => @account} %>
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# <%= render :partial => @account %>
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#
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# # @posts is an array of Post instances, so every post record returns 'posts/post' on `to_partial_path`,
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# # that's why we can replace:
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# # <%= render :partial => "posts/post", :collection => @posts %>
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# <%= render :partial => @posts %>
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#
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# == Rendering the default case
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#
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# If you're not going to be using any of the options like collections or layouts, you can also use the short-hand
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# defaults of render to render partials. Examples:
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#
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# # Instead of <%= render :partial => "account" %>
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# <%= render "account" %>
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#
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# # Instead of <%= render :partial => "account", :locals => { :account => @buyer } %>
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# <%= render "account", :account => @buyer %>
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#
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# # @account.to_partial_path returns 'accounts/account', so it can be used to replace:
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# # <%= render :partial => "accounts/account", :locals => { :account => @account} %>
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# <%= render @account %>
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#
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# # @posts is an array of Post instances, so every post record returns 'posts/post' on `to_partial_path`,
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# # that's why we can replace:
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# # <%= render :partial => "posts/post", :collection => @posts %>
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# <%= render @posts %>
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#
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# == Rendering partials with layouts
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#
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# Partials can have their own layouts applied to them. These layouts are different than the ones that are
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# specified globally for the entire action, but they work in a similar fashion. Imagine a list with two types
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# of users:
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#
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# <%# app/views/users/index.html.erb &>
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# Here's the administrator:
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# <%= render :partial => "user", :layout => "administrator", :locals => { :user => administrator } %>
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#
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# Here's the editor:
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# <%= render :partial => "user", :layout => "editor", :locals => { :user => editor } %>
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#
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# <%# app/views/users/_user.html.erb &>
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# Name: <%= user.name %>
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#
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# <%# app/views/users/_administrator.html.erb &>
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# <div id="administrator">
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# Budget: $<%= user.budget %>
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# <%= yield %>
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# </div>
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#
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# <%# app/views/users/_editor.html.erb &>
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# <div id="editor">
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# Deadline: <%= user.deadline %>
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# <%= yield %>
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# </div>
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#
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# ...this will return:
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#
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# Here's the administrator:
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# <div id="administrator">
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# Budget: $<%= user.budget %>
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# Name: <%= user.name %>
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# </div>
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#
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# Here's the editor:
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# <div id="editor">
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# Deadline: <%= user.deadline %>
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# Name: <%= user.name %>
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# </div>
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#
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# If a collection is given, the layout will be rendered once for each item in
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# the collection. Just think these two snippets have the same output:
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#
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# <%# app/views/users/_user.html.erb %>
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# Name: <%= user.name %>
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#
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# <%# app/views/users/index.html.erb %>
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# <%# This does not use layouts %>
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# <ul>
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# <% users.each do |user| -%>
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# <li>
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# <%= render :partial => "user", :locals => { :user => user } %>
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# </li>
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# <% end -%>
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# </ul>
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#
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# <%# app/views/users/_li_layout.html.erb %>
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# <li>
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# <%= yield %>
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# </li>
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#
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# <%# app/views/users/index.html.erb %>
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# <ul>
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# <%= render :partial => "user", :layout => "li_layout", :collection => users %>
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# </ul>
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#
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# Given two users whose names are Alice and Bob, these snippets return:
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#
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# <ul>
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# <li>
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# Name: Alice
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# </li>
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# <li>
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# Name: Bob
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# </li>
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# </ul>
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#
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# The current object being rendered, as well as the object_counter, will be
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# available as local variables inside the layout template under the same names
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# as available in the partial.
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#
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# You can also apply a layout to a block within any template:
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#
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# <%# app/views/users/_chief.html.erb &>
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# <%= render(:layout => "administrator", :locals => { :user => chief }) do %>
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# Title: <%= chief.title %>
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# <% end %>
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#
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# ...this will return:
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#
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# <div id="administrator">
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# Budget: $<%= user.budget %>
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# Title: <%= chief.name %>
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# </div>
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#
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# As you can see, the <tt>:locals</tt> hash is shared between both the partial and its layout.
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#
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# If you pass arguments to "yield" then this will be passed to the block. One way to use this is to pass
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# an array to layout and treat it as an enumerable.
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#
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# <%# app/views/users/_user.html.erb &>
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# <div class="user">
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# Budget: $<%= user.budget %>
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# <%= yield user %>
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# </div>
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#
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# <%# app/views/users/index.html.erb &>
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# <%= render :layout => @users do |user| %>
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# Title: <%= user.title %>
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# <% end %>
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#
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# This will render the layout for each user and yield to the block, passing the user, each time.
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#
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# You can also yield multiple times in one layout and use block arguments to differentiate the sections.
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#
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# <%# app/views/users/_user.html.erb &>
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# <div class="user">
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# <%= yield user, :header %>
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# Budget: $<%= user.budget %>
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# <%= yield user, :footer %>
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# </div>
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#
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# <%# app/views/users/index.html.erb &>
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# <%= render :layout => @users do |user, section| %>
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# <%- case section when :header -%>
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# Title: <%= user.title %>
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# <%- when :footer -%>
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# Deadline: <%= user.deadline %>
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# <%- end -%>
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# <% end %>
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class PartialRenderer < AbstractRenderer
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PREFIXED_PARTIAL_NAMES = Hash.new { |h,k| h[k] = {} }
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def initialize(*)
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super
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@context_prefix = @lookup_context.prefixes.first
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end
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def render(context, options, block)
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setup(context, options, block)
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identifier = (@template = find_partial) ? @template.identifier : @path
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@lookup_context.rendered_format ||= begin
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if @template && @template.formats.present?
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@template.formats.first
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else
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formats.first
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end
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end
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if @collection
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instrument(:collection, :identifier => identifier || "collection", :count => @collection.size) do
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render_collection
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end
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else
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instrument(:partial, :identifier => identifier) do
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render_partial
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end
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end
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end
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def render_collection
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return nil if @collection.blank?
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if @options.key?(:spacer_template)
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spacer = find_template(@options[:spacer_template], @locals.keys).render(@view, @locals)
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end
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result = @template ? collection_with_template : collection_without_template
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result.join(spacer).html_safe
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end
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def render_partial
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view, locals, block = @view, @locals, @block
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object, as = @object, @variable
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if !block && (layout = @options[:layout])
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layout = find_template(layout, @template_keys)
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end
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object ||= locals[as]
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locals[as] = object
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content = @template.render(view, locals) do |*name|
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view._layout_for(*name, &block)
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end
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content = layout.render(view, locals){ content } if layout
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content
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end
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private
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def setup(context, options, block)
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@view = context
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partial = options[:partial]
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@options = options
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@locals = options[:locals] || {}
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@block = block
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@details = extract_details(options)
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prepend_formats(options[:formats])
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if String === partial
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@object = options[:object]
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@path = partial
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@collection = collection
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else
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@object = partial
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if @collection = collection_from_object || collection
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paths = @collection_data = @collection.map { |o| partial_path(o) }
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@path = paths.uniq.size == 1 ? paths.first : nil
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else
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@path = partial_path
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end
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end
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if as = options[:as]
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raise_invalid_identifier(as) unless as.to_s =~ /\A[a-z_]\w*\z/
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as = as.to_sym
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end
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if @path
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@variable, @variable_counter = retrieve_variable(@path, as)
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@template_keys = retrieve_template_keys
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else
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paths.map! { |path| retrieve_variable(path, as).unshift(path) }
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end
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self
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end
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def collection
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if @options.key?(:collection)
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collection = @options[:collection]
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collection.respond_to?(:to_ary) ? collection.to_ary : []
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end
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end
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def collection_from_object
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@object.to_ary if @object.respond_to?(:to_ary)
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end
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def find_partial
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if path = @path
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find_template(path, @template_keys)
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end
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end
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def find_template(path, locals)
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prefixes = path.include?(?/) ? [] : @lookup_context.prefixes
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@lookup_context.find_template(path, prefixes, true, locals, @details)
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end
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def collection_with_template
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view, locals, template = @view, @locals, @template
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as, counter = @variable, @variable_counter
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if layout = @options[:layout]
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layout = find_template(layout, @template_keys)
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end
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index = -1
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@collection.map do |object|
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locals[as] = object
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locals[counter] = (index += 1)
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content = template.render(view, locals)
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content = layout.render(view, locals) { content } if layout
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content
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end
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end
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def collection_without_template
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view, locals, collection_data = @view, @locals, @collection_data
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cache = {}
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keys = @locals.keys
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index = -1
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@collection.map do |object|
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index += 1
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path, as, counter = collection_data[index]
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locals[as] = object
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locals[counter] = index
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template = (cache[path] ||= find_template(path, keys + [as, counter]))
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template.render(view, locals)
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end
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end
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def partial_path(object = @object)
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object = object.to_model if object.respond_to?(:to_model)
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path = if object.respond_to?(:to_partial_path)
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object.to_partial_path
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else
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raise ArgumentError.new("'#{object.inspect}' is not an ActiveModel-compatible object. It must implement :to_partial_path.")
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end
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if @view.prefix_partial_path_with_controller_namespace
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prefixed_partial_names[path] ||= merge_prefix_into_object_path(@context_prefix, path.dup)
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else
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path
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end
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end
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def prefixed_partial_names
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@prefixed_partial_names ||= PREFIXED_PARTIAL_NAMES[@context_prefix]
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end
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def merge_prefix_into_object_path(prefix, object_path)
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if prefix.include?(?/) && object_path.include?(?/)
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prefixes = []
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prefix_array = File.dirname(prefix).split('/')
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object_path_array = object_path.split('/')[0..-3] # skip model dir & partial
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prefix_array.each_with_index do |dir, index|
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break if dir == object_path_array[index]
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prefixes << dir
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end
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(prefixes << object_path).join("/")
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else
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object_path
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end
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end
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def retrieve_template_keys
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keys = @locals.keys
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keys << @variable
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keys << @variable_counter if @collection
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keys
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end
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def retrieve_variable(path, as)
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variable = as || begin
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base = path[-1] == "/" ? "" : File.basename(path)
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raise_invalid_identifier(path) unless base =~ /\A_?([a-z]\w*)(\.\w+)*\z/
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$1.to_sym
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end
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variable_counter = :"#{variable}_counter" if @collection
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[variable, variable_counter]
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end
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IDENTIFIER_ERROR_MESSAGE = "The partial name (%s) is not a valid Ruby identifier; " +
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"make sure your partial name starts with a lowercase letter or underscore, " +
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"and is followed by any combination of letters, numbers and underscores."
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def raise_invalid_identifier(path)
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raise ArgumentError.new(IDENTIFIER_ERROR_MESSAGE % (path))
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end
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end
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end
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