require 'set' module ActionController 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 Action Pack. The key benefit of this is # that filters run before the cache is served, which allows for # authentication and other restrictions on whether someone is allowed # to execute such action. # # class ListsController < ApplicationController # before_filter :authenticate, except: :public # # caches_page :public # caches_action :index, :show # end # # In this example, the +public+ action doesn't require authentication # so it's possible to use the faster page caching. On the other hand # +index+ and +show+ require authentication. They can still be cached, # but we need action caching for them. # # Action caching uses fragment caching internally and an around # filter to do the job. The fragment cache is named according to # the host and path of the request. A page that is accessed at # http://david.example.com/lists/show/1 will result in a fragment named # david.example.com/lists/show/1. This allows the cacher to # differentiate between david.example.com/lists/ and # jamis.example.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.example.com/lists and # http://david.example.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 modify the default action cache path by passing a # :cache_path option. This will be passed directly to # ActionCachePath.new. 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. # # And you can also use :if (or :unless) to pass a # proc that specifies when the action should be cached. # # As of Rails 3.0, you can also pass :expires_in with a time # interval (in seconds) to schedule expiration of the cached item. # # The following example depicts some of the points made above: # # class ListsController < ApplicationController # before_filter :authenticate, except: :public # # caches_page :public # # caches_action :index, if: Proc.new do # !request.format.json? # cache if is not a JSON request # end # # caches_action :show, cache_path: { project: 1 }, # expires_in: 1.hour # # caches_action :feed, cache_path: Proc.new do # if params[:user_id] # user_list_url(params[:user_id, params[:id]) # else # list_url(params[:id]) # end # end # end # # If you pass layout: false, it will only cache your action # content. That's useful when your layout has dynamic information. # # Warning: If the format of the request is determined by the Accept HTTP # header the Content-Type of the cached response could be wrong because # no information about the MIME type is stored in the cache key. So, if # you first ask for MIME type M in the Accept header, a cache entry is # created, and then perform a second request to the same resource asking # for a different MIME type, you'd get the content cached for M. # # The :format parameter is taken into account though. The safest # way to cache by MIME type is to pass the format in the route. module Actions extend ActiveSupport::Concern module ClassMethods # Declares that +actions+ should be cached. # See ActionController::Caching::Actions for details. def caches_action(*actions) return unless cache_configured? options = actions.extract_options! options[:layout] = true unless options.key?(:layout) filter_options = options.extract!(:if, :unless).merge(:only => actions) cache_options = options.extract!(:layout, :cache_path).merge(:store_options => options) around_filter ActionCacheFilter.new(cache_options), filter_options end end def _save_fragment(name, options) content = "" response_body.each do |parts| content << parts end if caching_allowed? write_fragment(name, content, options) else content end end protected def expire_action(options = {}) return unless cache_configured? if options.is_a?(Hash) && options[:action].is_a?(Array) options[:action].each {|action| expire_action(options.merge(:action => action)) } else expire_fragment(ActionCachePath.new(self, options, false).path) end end class ActionCacheFilter #:nodoc: def initialize(options, &block) @cache_path, @store_options, @cache_layout = options.values_at(:cache_path, :store_options, :layout) end def around(controller) cache_layout = @cache_layout.respond_to?(:call) ? @cache_layout.call(controller) : @cache_layout path_options = if @cache_path.respond_to?(:call) controller.instance_exec(controller, &@cache_path) else @cache_path end cache_path = ActionCachePath.new(controller, path_options || {}) body = controller.read_fragment(cache_path.path, @store_options) unless body controller.action_has_layout = false unless cache_layout yield controller.action_has_layout = true body = controller._save_fragment(cache_path.path, @store_options) end body = controller.render_to_string(:text => body, :layout => true) unless cache_layout controller.response_body = body controller.content_type = Mime[cache_path.extension || :html] end end class ActionCachePath attr_reader :path, :extension # If +infer_extension+ is +true+, the cache path extension is looked up from the request's # path and format. This is desirable when reading and writing the cache, but not when # expiring the cache - +expire_action+ should expire the same files regardless of the # request format. def initialize(controller, options = {}, infer_extension = true) if infer_extension @extension = controller.params[:format] options.reverse_merge!(:format => @extension) if options.is_a?(Hash) end path = controller.url_for(options).split('://', 2).last @path = normalize!(path) end private def normalize!(path) ext = URI.parser.escape(extension) if extension path << 'index' if path[-1] == ?/ path << ".#{ext}" if extension and !path.split('?', 2).first.ends_with?(".#{ext}") URI.parser.unescape(path) end end end end end