module ActionController #:nodoc:
module Caching
# Sweepers are the terminators of the caching world and responsible for expiring caches when model objects change.
# They do this by being half-observers, half-filters and implementing callbacks for both roles. A Sweeper example:
#
# class ListSweeper < ActionController::Caching::Sweeper
# observe List, Item
#
# def after_save(record)
# list = record.is_a?(List) ? record : record.list
# expire_page(:controller => "lists", :action => %w( show public feed ), :id => list.id)
# expire_action(:controller => "lists", :action => "all")
# list.shares.each { |share| expire_page(:controller => "lists", :action => "show", :id => share.url_key) }
# end
# end
#
# The sweeper is assigned in the controllers that wish to have its job performed using the <tt>cache_sweeper</tt> class method:
#
# class ListsController < ApplicationController
# caches_action :index, :show, :public, :feed
# cache_sweeper :list_sweeper, :only => [ :edit, :destroy, :share ]
# end
#
# In the example above, four actions are cached and three actions are responsible for expiring those caches.
#
# You can also name an explicit class in the declaration of a sweeper, which is needed if the sweeper is in a module:
#
# class ListsController < ApplicationController
# caches_action :index, :show, :public, :feed
# cache_sweeper OpenBar::Sweeper, :only => [ :edit, :destroy, :share ]
# end
module Sweeping
def self.included(base) #:nodoc:
base.extend(ClassMethods)
end
module ClassMethods #:nodoc:
def cache_sweeper(*sweepers)
configuration = sweepers.extract_options!
sweepers.each do |sweeper|
ActiveRecord::Base.observers << sweeper if defined?(ActiveRecord) and defined?(ActiveRecord::Base)
sweeper_instance = (sweeper.is_a?(Symbol) ? Object.const_get(sweeper.to_s.classify) : sweeper).instance
if sweeper_instance.is_a?(Sweeper)
around_filter(sweeper_instance, :only => configuration[:only])
else
after_filter(sweeper_instance, :only => configuration[:only])
end
end
end
end
end
if defined?(ActiveRecord) and defined?(ActiveRecord::Observer)
class Sweeper < ActiveRecord::Observer #:nodoc:
attr_accessor :controller
def before(controller)
self.controller = controller
callback(:before) if controller.perform_caching
end
def after(controller)
callback(:after) if controller.perform_caching
# Clean up, so that the controller can be collected after this request
self.controller = nil
end
protected
# gets the action cache path for the given options.
def action_path_for(options)
Actions::ActionCachePath.new(controller, options).path
end
# Retrieve instance variables set in the controller.
def assigns(key)
controller.instance_variable_get("@#{key}")
end
private
def callback(timing)
controller_callback_method_name = "#{timing}_#{controller.controller_name.underscore}"
action_callback_method_name = "#{controller_callback_method_name}_#{controller.action_name}"
__send__(controller_callback_method_name) if respond_to?(controller_callback_method_name, true)
__send__(action_callback_method_name) if respond_to?(action_callback_method_name, true)
end
def method_missing(method, *arguments, &block)
return if @controller.nil?
@controller.__send__(method, *arguments, &block)
end
end
end
end
end
