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