Module: ActionController::Caching::Actions

Defined in:
lib/action_controller/caching.rb

Overview

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 are supposed 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 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.

Defined Under Namespace

Modules: ClassMethods Classes: ActionCacheFilter

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.append_features(base) ⇒ Object

:nodoc:


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# File 'lib/action_controller/caching.rb', line 159

def self.append_features(base) #:nodoc:
  super
  base.extend(ClassMethods)
  base.send(:attr_accessor, :rendered_action_cache)
end

Instance Method Details

#expire_action(options = {}) ⇒ Object


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# File 'lib/action_controller/caching.rb', line 172

def expire_action(options = {})
  return unless perform_caching
  if options[:action].is_a?(Array)
    options[:action].dup.each do |action|
      expire_fragment(url_for(options.merge({ :action => action })).split("://").last)
    end
  else
    expire_fragment(url_for(options).split("://").last)
  end
end