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 :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.
#
# class ListsController < ApplicationController
# before_filter :authenticate, :except => :public
# caches_page :public
# caches_action :show, :cache_path => { :project => 1 }
# caches_action :show, :cache_path => Proc.new { |controller|
# controller.params[:user_id] ?
# controller.send(:user_list_url, c.params[:user_id], c.params[:id]) :
# controller.send(:list_url, c.params[:id]) }
# end
module Actions
def self.included(base) #:nodoc:
base.extend(ClassMethods)
base.class_eval do
attr_accessor :rendered_action_cache, :action_cache_path
alias_method_chain :protected_instance_variables, :action_caching
end
end
module ClassMethods
# Declares that +actions+ should be cached.
# See ActionController::Caching::Actions for details.
def caches_action(*actions)
return unless cache_configured?
around_filter(ActionCacheFilter.new(*actions))
end
end
protected
def protected_instance_variables_with_action_caching
protected_instance_variables_without_action_caching + %w(@action_cache_path)
end
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 })))
end
else
expire_fragment(ActionCachePath.path_for(self, options))
end
end
class ActionCacheFilter #:nodoc:
def initialize(*actions, &block)
@options = actions.extract_options!
@actions = Set.new(actions)
end
def before(controller)
return unless @actions.include?(controller.action_name.intern)
cache_path = ActionCachePath.new(controller, path_options_for(controller, @options))
if cache = controller.read_fragment(cache_path.path)
controller.rendered_action_cache = true
set_content_type!(controller, cache_path.extension)
controller.send!(:render_for_text, cache)
false
else
controller.action_cache_path = cache_path
end
end
def after(controller)
return if !@actions.include?(controller.action_name.intern) || controller.rendered_action_cache || !caching_allowed(controller)
controller.write_fragment(controller.action_cache_path.path, controller.response.body)
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.headers['Status'].to_i == 200
end
end
class ActionCachePath
attr_reader :path, :extension
class << self
def path_for(controller, options)
new(controller, options).path
end
end
def initialize(controller, options = {})
@extension = extract_extension(controller.request.path)
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
end
def extract_extension(file_path)
# Don't want just what comes after the last '.' to accommodate multi part extensions
# such as tar.gz.
file_path[/^[^.]+\.(.+)$/, 1]
end
end
end
end
end
