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 :index, :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. <tt>http://david.somewhere.com/lists</tt> and <tt>http://david.somewhere.com/lists.xml</tt>
# are treated like separate requests and so are cached separately. Keep in mind when expiring an action cache that <tt>:action => 'lists'</tt> is not the same
# as <tt>:action => 'list', :format => :xml</tt>.
#
# 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.
#
# And you can also use :if (or :unless) to pass a Proc that specifies when the action should be cached.
#
# Finally, if you are using memcached, you can also pass :expires_in.
#
# class ListsController < ApplicationController
# before_filter :authenticate, :except => :public
# caches_page :public
# caches_action :index, :if => Proc.new { |c| !c.request.format.json? } # cache if is not a JSON request
# caches_action :show, :cache_path => { :project => 1 }, :expires_in => 1.hour
# caches_action :feed, :cache_path => Proc.new { |controller|
# controller.params[:user_id] ?
# controller.send(:user_list_url, controller.params[:user_id], controller.params[:id]) :
# controller.send(:list_url, controller.params[:id]) }
# end
#
# If you pass :layout => false, it will only cache your action content. It is useful when your layout has dynamic information.
#
module Actions
def self.included(base) #:nodoc:
base.extend(ClassMethods)
base.class_eval do
attr_accessor :rendered_action_cache, :action_cache_path
end
end
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!
filter_options = { :only => actions, :if => options.delete(:if), :unless => options.delete(:unless) }
cache_filter = ActionCacheFilter.new(:layout => options.delete(:layout), :cache_path => options.delete(:cache_path), :store_options => options)
around_filter(filter_options) do |controller, action|
cache_filter.filter(controller, action)
end
end
end
protected
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 }), false))
end
else
expire_fragment(ActionCachePath.path_for(self, options, false))
end
end
class ActionCacheFilter #:nodoc:
def initialize(options, &block)
@options = options
end
def filter(controller, action)
should_continue = before(controller)
action.call if should_continue
after(controller)
end
def before(controller)
cache_path = ActionCachePath.new(controller, path_options_for(controller, @options.slice(:cache_path)))
if cache = controller.read_fragment(cache_path.path, @options[:store_options])
controller.rendered_action_cache = true
set_content_type!(controller, cache_path.extension)
options = { :text => cache }
options.merge!(:layout => true) if cache_layout?
controller.__send__(:render, options)
false
else
controller.action_cache_path = cache_path
end
end
def after(controller)
return if controller.rendered_action_cache || !caching_allowed(controller)
action_content = cache_layout? ? content_for_layout(controller) : controller.response.body
controller.write_fragment(controller.action_cache_path.path, action_content, @options[:store_options])
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.status.to_i == 200
end
def cache_layout?
@options[:layout] == false
end
def content_for_layout(controller)
controller.template.layout && controller.template.instance_variable_get('@cached_content_for_layout')
end
end
class ActionCachePath
attr_reader :path, :extension
class << self
def path_for(controller, options, infer_extension = true)
new(controller, options, infer_extension).path
end
end
# If +infer_extension+ is true, the cache path extension is looked up from the request's path & 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
extract_extension(controller.request)
options = options.reverse_merge(:format => @extension) if options.is_a?(Hash)
end
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 and !path.ends_with?(extension)
end
def extract_extension(request)
# Don't want just what comes after the last '.' to accommodate multi part extensions
# such as tar.gz.
@extension = request.path[/^[^.]+\.(.+)$/, 1] || request.cache_format
end
end
end
end
end
