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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 do |c|
# !c.request.format.json? # cache if is not a JSON request
# end
#
# caches_action :show, :cache_path => { :project => 1 },
# :expires_in => 1.hour
#
# caches_action :feed, :cache_path => proc do |controller|
# if controller.params[:user_id]
# controller.send(:user_list_url,
# controller.params[:user_id], controller.params[:id])
# else
# controller.send(:list_url, controller.params[:id])
# end
# end
# 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
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)
render :text => cache, :layout => layout, :content_type => Mime[extension || :html]
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.new(self, options, false).path)
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 = if @cache_path.respond_to?(:call)
controller.instance_exec(controller, &@cache_path)
else
@cache_path
end
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
# 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
@extension = controller.params[:format]
options.reverse_merge!(:format => @extension) if options.is_a?(Hash)
end
path = controller.url_for(options).split(%r{://}).last
@path = normalize!(path)
end
private
def normalize!(path)
path << 'index' if path[-1] == ?/
path << ".#{extension}" if extension and !path.ends_with?(extension)
URI.unescape(path)
end
end
end
end
end
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