170 lines
7.6 KiB
Ruby
170 lines
7.6 KiB
Ruby
require 'set'
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module ActionController #:nodoc:
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module Caching
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# Action caching is similar to page caching by the fact that the entire output of the response is cached, but unlike page caching,
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# every request still goes through the Action Pack. The key benefit of this is that filters are run before the cache is served, which
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# allows for authentication and other restrictions on whether someone is allowed to see the cache. Example:
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#
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# class ListsController < ApplicationController
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# before_filter :authenticate, :except => :public
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# caches_page :public
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# caches_action :index, :show, :feed
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# end
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#
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# In this example, the public action doesn't require authentication, so it's possible to use the faster page caching method. But both the
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# show and feed action are to be shielded behind the authenticate filter, so we need to implement those as action caches.
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#
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# Action caching internally uses the fragment caching and an around filter to do the job. The fragment cache is named according to both
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# 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
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# "david.somewhere.com/lists/show/1". This allows the cacher to differentiate between "david.somewhere.com/lists/" and
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# "jamis.somewhere.com/lists/" -- which is a helpful way of assisting the subdomain-as-account-key pattern.
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#
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# Different representations of the same resource, e.g. <tt>http://david.somewhere.com/lists</tt> and <tt>http://david.somewhere.com/lists.xml</tt>
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# 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
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# as <tt>:action => 'list', :format => :xml</tt>.
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#
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# 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
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# for actions with multiple possible routes that should be cached differently. If a block is given, it is called with the current controller instance.
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#
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# And you can also use :if (or :unless) to pass a Proc that specifies when the action should be cached.
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#
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# Finally, if you are using memcached, you can also pass :expires_in.
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#
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# class ListsController < ApplicationController
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# before_filter :authenticate, :except => :public
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# caches_page :public
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# caches_action :index, :if => Proc.new { |c| !c.request.format.json? } # cache if is not a JSON request
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# caches_action :show, :cache_path => { :project => 1 }, :expires_in => 1.hour
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# caches_action :feed, :cache_path => Proc.new { |controller|
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# controller.params[:user_id] ?
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# controller.send(:user_list_url, controller.params[:user_id], controller.params[:id]) :
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# controller.send(:list_url, controller.params[:id]) }
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# end
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#
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# If you pass :layout => false, it will only cache your action content. It is useful when your layout has dynamic information.
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#
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module Actions
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def self.included(base) #:nodoc:
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base.extend(ClassMethods)
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base.class_eval do
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attr_accessor :rendered_action_cache, :action_cache_path
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end
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end
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module ClassMethods
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# Declares that +actions+ should be cached.
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# See ActionController::Caching::Actions for details.
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def caches_action(*actions)
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return unless cache_configured?
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options = actions.extract_options!
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filter_options = { :only => actions, :if => options.delete(:if), :unless => options.delete(:unless) }
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cache_filter = ActionCacheFilter.new(:layout => options.delete(:layout), :cache_path => options.delete(:cache_path), :store_options => options)
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around_filter(cache_filter, filter_options)
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end
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end
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protected
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def expire_action(options = {})
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return unless cache_configured?
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if options[:action].is_a?(Array)
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options[:action].dup.each do |action|
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expire_fragment(ActionCachePath.path_for(self, options.merge({ :action => action }), false))
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end
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else
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expire_fragment(ActionCachePath.path_for(self, options, false))
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end
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end
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class ActionCacheFilter #:nodoc:
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def initialize(options, &block)
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@options = options
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end
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def before(controller)
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cache_path = ActionCachePath.new(controller, path_options_for(controller, @options.slice(:cache_path)))
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if cache = controller.read_fragment(cache_path.path, @options[:store_options])
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controller.rendered_action_cache = true
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set_content_type!(controller, cache_path.extension)
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options = { :text => cache }
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options.merge!(:layout => true) if cache_layout?
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controller.__send__(:render, options)
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false
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else
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controller.action_cache_path = cache_path
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end
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end
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def after(controller)
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return if controller.rendered_action_cache || !caching_allowed(controller)
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action_content = cache_layout? ? content_for_layout(controller) : controller.response.body
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controller.write_fragment(controller.action_cache_path.path, action_content, @options[:store_options])
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end
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private
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def set_content_type!(controller, extension)
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controller.response.content_type = Mime::Type.lookup_by_extension(extension).to_s if extension
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end
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def path_options_for(controller, options)
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((path_options = options[:cache_path]).respond_to?(:call) ? path_options.call(controller) : path_options) || {}
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end
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def caching_allowed(controller)
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controller.request.get? && controller.response.status.to_i == 200
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end
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def cache_layout?
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@options[:layout] == false
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end
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def content_for_layout(controller)
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controller.template.layout && controller.template.instance_variable_get('@cached_content_for_layout')
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end
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end
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class ActionCachePath
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attr_reader :path, :extension
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class << self
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def path_for(controller, options, infer_extension = true)
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new(controller, options, infer_extension).path
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end
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end
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# If +infer_extension+ is true, the cache path extension is looked up from the request's path & format.
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# This is desirable when reading and writing the cache, but not when expiring the cache -
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# expire_action should expire the same files regardless of the request format.
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def initialize(controller, options = {}, infer_extension = true)
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if infer_extension
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extract_extension(controller.request)
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options = options.reverse_merge(:format => @extension) if options.is_a?(Hash)
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end
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path = controller.url_for(options).split('://').last
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normalize!(path)
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add_extension!(path, @extension)
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@path = URI.unescape(path)
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end
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private
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def normalize!(path)
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path << 'index' if path[-1] == ?/
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end
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def add_extension!(path, extension)
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path << ".#{extension}" if extension and !path.ends_with?(extension)
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end
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def extract_extension(request)
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# Don't want just what comes after the last '.' to accommodate multi part extensions
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# such as tar.gz.
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@extension = request.path[/^[^.]+\.(.+)$/, 1] || request.cache_format
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end
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end
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end
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end
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end
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