e2ccdfd812
Update to Rails 2.3.2 (the stable Rails 2.3 release). Add audio/speex support Update CHANGELOG Bump version number
281 lines
12 KiB
Ruby
281 lines
12 KiB
Ruby
module ActionController #:nodoc:
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module Layout #:nodoc:
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def self.included(base)
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base.extend(ClassMethods)
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base.class_eval do
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class << self
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alias_method_chain :inherited, :layout
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end
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end
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end
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# Layouts reverse the common pattern of including shared headers and footers in many templates to isolate changes in
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# repeated setups. The inclusion pattern has pages that look like this:
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#
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# <%= render "shared/header" %>
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# Hello World
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# <%= render "shared/footer" %>
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#
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# This approach is a decent way of keeping common structures isolated from the changing content, but it's verbose
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# and if you ever want to change the structure of these two includes, you'll have to change all the templates.
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#
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# With layouts, you can flip it around and have the common structure know where to insert changing content. This means
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# that the header and footer are only mentioned in one place, like this:
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#
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# // The header part of this layout
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# <%= yield %>
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# // The footer part of this layout
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#
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# And then you have content pages that look like this:
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#
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# hello world
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#
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# At rendering time, the content page is computed and then inserted in the layout, like this:
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#
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# // The header part of this layout
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# hello world
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# // The footer part of this layout
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#
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# NOTE: The old notation for rendering the view from a layout was to expose the magic <tt>@content_for_layout</tt> instance
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# variable. The preferred notation now is to use <tt>yield</tt>, as documented above.
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#
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# == Accessing shared variables
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#
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# Layouts have access to variables specified in the content pages and vice versa. This allows you to have layouts with
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# references that won't materialize before rendering time:
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#
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# <h1><%= @page_title %></h1>
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# <%= yield %>
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#
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# ...and content pages that fulfill these references _at_ rendering time:
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#
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# <% @page_title = "Welcome" %>
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# Off-world colonies offers you a chance to start a new life
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#
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# The result after rendering is:
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#
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# <h1>Welcome</h1>
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# Off-world colonies offers you a chance to start a new life
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#
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# == Automatic layout assignment
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#
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# If there is a template in <tt>app/views/layouts/</tt> with the same name as the current controller then it will be automatically
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# set as that controller's layout unless explicitly told otherwise. Say you have a WeblogController, for example. If a template named
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# <tt>app/views/layouts/weblog.erb</tt> or <tt>app/views/layouts/weblog.builder</tt> exists then it will be automatically set as
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# the layout for your WeblogController. You can create a layout with the name <tt>application.erb</tt> or <tt>application.builder</tt>
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# and this will be set as the default controller if there is no layout with the same name as the current controller and there is
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# no layout explicitly assigned with the +layout+ method. Nested controllers use the same folder structure for automatic layout.
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# assignment. So an Admin::WeblogController will look for a template named <tt>app/views/layouts/admin/weblog.erb</tt>.
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# Setting a layout explicitly will always override the automatic behaviour for the controller where the layout is set.
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# Explicitly setting the layout in a parent class, though, will not override the child class's layout assignment if the child
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# class has a layout with the same name.
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#
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# == Inheritance for layouts
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#
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# Layouts are shared downwards in the inheritance hierarchy, but not upwards. Examples:
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#
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# class BankController < ActionController::Base
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# layout "bank_standard"
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#
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# class InformationController < BankController
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#
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# class VaultController < BankController
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# layout :access_level_layout
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#
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# class EmployeeController < BankController
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# layout nil
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#
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# The InformationController uses "bank_standard" inherited from the BankController, the VaultController overwrites
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# and picks the layout dynamically, and the EmployeeController doesn't want to use a layout at all.
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#
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# == Types of layouts
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#
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# Layouts are basically just regular templates, but the name of this template needs not be specified statically. Sometimes
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# you want to alternate layouts depending on runtime information, such as whether someone is logged in or not. This can
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# be done either by specifying a method reference as a symbol or using an inline method (as a proc).
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#
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# The method reference is the preferred approach to variable layouts and is used like this:
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#
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# class WeblogController < ActionController::Base
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# layout :writers_and_readers
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#
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# def index
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# # fetching posts
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# end
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#
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# private
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# def writers_and_readers
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# logged_in? ? "writer_layout" : "reader_layout"
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# end
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#
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# Now when a new request for the index action is processed, the layout will vary depending on whether the person accessing
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# is logged in or not.
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#
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# If you want to use an inline method, such as a proc, do something like this:
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#
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# class WeblogController < ActionController::Base
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# layout proc{ |controller| controller.logged_in? ? "writer_layout" : "reader_layout" }
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#
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# Of course, the most common way of specifying a layout is still just as a plain template name:
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#
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# class WeblogController < ActionController::Base
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# layout "weblog_standard"
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#
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# If no directory is specified for the template name, the template will by default be looked for in <tt>app/views/layouts/</tt>.
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# Otherwise, it will be looked up relative to the template root.
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#
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# == Conditional layouts
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#
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# If you have a layout that by default is applied to all the actions of a controller, you still have the option of rendering
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# a given action or set of actions without a layout, or restricting a layout to only a single action or a set of actions. The
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# <tt>:only</tt> and <tt>:except</tt> options can be passed to the layout call. For example:
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#
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# class WeblogController < ActionController::Base
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# layout "weblog_standard", :except => :rss
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#
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# # ...
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#
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# end
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#
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# This will assign "weblog_standard" as the WeblogController's layout except for the +rss+ action, which will not wrap a layout
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# around the rendered view.
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#
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# Both the <tt>:only</tt> and <tt>:except</tt> condition can accept an arbitrary number of method references, so
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# #<tt>:except => [ :rss, :text_only ]</tt> is valid, as is <tt>:except => :rss</tt>.
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#
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# == Using a different layout in the action render call
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#
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# If most of your actions use the same layout, it makes perfect sense to define a controller-wide layout as described above.
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# Sometimes you'll have exceptions where one action wants to use a different layout than the rest of the controller.
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# You can do this by passing a <tt>:layout</tt> option to the <tt>render</tt> call. For example:
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#
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# class WeblogController < ActionController::Base
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# layout "weblog_standard"
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#
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# def help
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# render :action => "help", :layout => "help"
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# end
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# end
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#
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# This will render the help action with the "help" layout instead of the controller-wide "weblog_standard" layout.
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module ClassMethods
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# If a layout is specified, all rendered actions will have their result rendered
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# when the layout <tt>yield</tt>s. This layout can itself depend on instance variables assigned during action
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# performance and have access to them as any normal template would.
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def layout(template_name, conditions = {}, auto = false)
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add_layout_conditions(conditions)
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write_inheritable_attribute(:layout, template_name)
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write_inheritable_attribute(:auto_layout, auto)
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end
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def layout_conditions #:nodoc:
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@layout_conditions ||= read_inheritable_attribute(:layout_conditions)
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end
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def layout_list #:nodoc:
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Array(view_paths).sum([]) { |path| Dir["#{path.to_str}/layouts/**/*"] }
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end
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private
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def inherited_with_layout(child)
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inherited_without_layout(child)
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unless child.name.blank?
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layout_match = child.name.underscore.sub(/_controller$/, '').sub(/^controllers\//, '')
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child.layout(layout_match, {}, true) unless child.layout_list.grep(%r{layouts/#{layout_match}(\.[a-z][0-9a-z]*)+$}).empty?
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end
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end
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def add_layout_conditions(conditions)
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write_inheritable_hash(:layout_conditions, normalize_conditions(conditions))
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end
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def normalize_conditions(conditions)
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conditions.inject({}) {|hash, (key, value)| hash.merge(key => [value].flatten.map {|action| action.to_s})}
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end
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end
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# Returns the name of the active layout. If the layout was specified as a method reference (through a symbol), this method
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# is called and the return value is used. Likewise if the layout was specified as an inline method (through a proc or method
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# object). If the layout was defined without a directory, layouts is assumed. So <tt>layout "weblog/standard"</tt> will return
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# weblog/standard, but <tt>layout "standard"</tt> will return layouts/standard.
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def active_layout(passed_layout = nil, options = {})
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layout = passed_layout || default_layout
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return layout if layout.respond_to?(:render)
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active_layout = case layout
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when Symbol then __send__(layout)
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when Proc then layout.call(self)
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else layout
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end
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find_layout(active_layout, default_template_format, options[:html_fallback]) if active_layout
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end
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private
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def default_layout #:nodoc:
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layout = self.class.read_inheritable_attribute(:layout)
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return layout unless self.class.read_inheritable_attribute(:auto_layout)
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find_layout(layout, default_template_format)
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rescue ActionView::MissingTemplate
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nil
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end
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def find_layout(layout, format, html_fallback=false) #:nodoc:
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view_paths.find_template(layout.to_s =~ /layouts\// ? layout : "layouts/#{layout}", format, html_fallback)
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rescue ActionView::MissingTemplate
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raise if Mime::Type.lookup_by_extension(format.to_s).html?
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end
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def pick_layout(options)
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if options.has_key?(:layout)
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case layout = options.delete(:layout)
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when FalseClass
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nil
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when NilClass, TrueClass
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active_layout if action_has_layout? && candidate_for_layout?(:template => default_template_name)
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else
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active_layout(layout, :html_fallback => true)
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end
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else
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active_layout if action_has_layout? && candidate_for_layout?(options)
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end
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end
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def action_has_layout?
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if conditions = self.class.layout_conditions
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case
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when only = conditions[:only]
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only.include?(action_name)
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when except = conditions[:except]
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!except.include?(action_name)
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else
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true
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end
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else
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true
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end
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end
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def candidate_for_layout?(options)
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template = options[:template] || default_template(options[:action])
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if options.values_at(:text, :xml, :json, :file, :inline, :partial, :nothing, :update).compact.empty?
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begin
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template_object = self.view_paths.find_template(template, default_template_format)
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# this restores the behavior from 2.2.2, where response.template.template_format was reset
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# to :html for :js requests with a matching html template.
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# see v2.2.2, ActionView::Base, lines 328-330
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@real_format = :html if response.template.template_format == :js && template_object.format == "html"
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!template_object.exempt_from_layout?
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rescue ActionView::MissingTemplate
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true
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end
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end
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rescue ActionView::MissingTemplate
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false
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end
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def default_template_format
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@real_format || response.template.template_format
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end
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end
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end
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