require 'set' module ActionController #:nodoc: module Caching # Action caching is similar to page caching by the fact that the entire output of the response is cached, but unlike page caching, # every request still goes through the Action Pack. The key benefit of this is that filters are run before the cache is served, which # allows for authentication and other restrictions on whether someone is allowed to see the cache. Example: # # class ListsController < ApplicationController # before_filter :authenticate, :except => :public # caches_page :public # caches_action :show, :feed # end # # In this example, the public action doesn't require authentication, so it's possible to use the faster page caching method. But both the # show and feed action are to be shielded behind the authenticate filter, so we need to implement those as action caches. # # Action caching internally uses the fragment caching and an around filter to do the job. The fragment cache is named according to both # the current host and the path. So a page that is accessed at http://david.somewhere.com/lists/show/1 will result in a fragment named # "david.somewhere.com/lists/show/1". This allows the cacher to differentiate between "david.somewhere.com/lists/" and # "jamis.somewhere.com/lists/" -- which is a helpful way of assisting the subdomain-as-account-key pattern. # # Different representations of the same resource, e.g. http://david.somewhere.com/lists and http://david.somewhere.com/lists.xml # are treated like separate requests and so are cached separately. Keep in mind when expiring an action cache that :action => 'lists' is not the same # as :action => 'list', :format => :xml. # # You can set modify the default action cache path by passing a :cache_path option. This will be passed directly to ActionCachePath.path_for. This is handy # for actions with multiple possible routes that should be cached differently. If a block is given, it is called with the current controller instance. # # class ListsController < ApplicationController # before_filter :authenticate, :except => :public # caches_page :public # caches_action :show, :cache_path => { :project => 1 } # caches_action :show, :cache_path => Proc.new { |controller| # controller.params[:user_id] ? # controller.send(:user_list_url, c.params[:user_id], c.params[:id]) : # controller.send(:list_url, c.params[:id]) } # end module Actions def self.included(base) #:nodoc: base.extend(ClassMethods) base.class_eval do attr_accessor :rendered_action_cache, :action_cache_path alias_method_chain :protected_instance_variables, :action_caching end end module ClassMethods # Declares that +actions+ should be cached. # See ActionController::Caching::Actions for details. def caches_action(*actions) return unless cache_configured? around_filter(ActionCacheFilter.new(*actions)) end end protected def protected_instance_variables_with_action_caching protected_instance_variables_without_action_caching + %w(@action_cache_path) end def expire_action(options = {}) return unless cache_configured? if options[:action].is_a?(Array) options[:action].dup.each do |action| expire_fragment(ActionCachePath.path_for(self, options.merge({ :action => action }))) end else expire_fragment(ActionCachePath.path_for(self, options)) end end class ActionCacheFilter #:nodoc: def initialize(*actions, &block) @options = actions.extract_options! @actions = Set.new(actions) end def before(controller) return unless @actions.include?(controller.action_name.intern) cache_path = ActionCachePath.new(controller, path_options_for(controller, @options)) if cache = controller.read_fragment(cache_path.path) controller.rendered_action_cache = true set_content_type!(controller, cache_path.extension) controller.send!(:render_for_text, cache) false else controller.action_cache_path = cache_path end end def after(controller) return if !@actions.include?(controller.action_name.intern) || controller.rendered_action_cache || !caching_allowed(controller) controller.write_fragment(controller.action_cache_path.path, controller.response.body) end private def set_content_type!(controller, extension) controller.response.content_type = Mime::Type.lookup_by_extension(extension).to_s if extension end def path_options_for(controller, options) ((path_options = options[:cache_path]).respond_to?(:call) ? path_options.call(controller) : path_options) || {} end def caching_allowed(controller) controller.request.get? && controller.response.headers['Status'].to_i == 200 end end class ActionCachePath attr_reader :path, :extension class << self def path_for(controller, options) new(controller, options).path end end def initialize(controller, options = {}) @extension = extract_extension(controller.request.path) path = controller.url_for(options).split('://').last normalize!(path) add_extension!(path, @extension) @path = URI.unescape(path) end private def normalize!(path) path << 'index' if path[-1] == ?/ end def add_extension!(path, extension) path << ".#{extension}" if extension end def extract_extension(file_path) # Don't want just what comes after the last '.' to accommodate multi part extensions # such as tar.gz. file_path[/^[^.]+\.(.+)$/, 1] end end end end end