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 { |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 { |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
extend ActiveSupport::Concern
included do
attr_accessor :rendered_action_cache, :action_cache_path
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 = 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 _render_cache_fragment(cache, extension, layout)
self.rendered_action_cache = true
response.content_type = Mime[extension].to_s if extension
options = { :text => cache }
options.merge!(:layout => true) if layout
render options
end
def _save_fragment(name, layout, options)
return unless caching_allowed?
content = layout ? view_context.content_for(:layout) : response_body
write_fragment(name, content, options)
end
protected
def expire_action(options = {})
return unless cache_configured?
actions = options[:action]
if actions.is_a?(Array)
actions.each {|action| expire_action(options.merge(:action => action)) }
else
expire_fragment(ActionCachePath.path_for(self, options, false))
end
end
class ActionCacheFilter #:nodoc:
def initialize(options, &block)
@cache_path, @store_options, @layout =
options.values_at(:cache_path, :store_options, :layout)
end
def filter(controller)
path_options = @cache_path.respond_to?(:call) ? @cache_path.call(controller) : @cache_path
cache_path = ActionCachePath.new(controller, path_options || {})
if cache = controller.read_fragment(cache_path.path, @store_options)
controller._render_cache_fragment(cache, cache_path.extension, @layout == false)
else
yield
controller._save_fragment(cache_path.path, @layout == false, @store_options)
end
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
