require 'fileutils' require 'uri' require 'set' module ActionController #:nodoc: # Caching is a cheap way of speeding up slow applications by keeping the result of calculations, renderings, and database calls # around for subsequent requests. Action Controller affords you three approaches in varying levels of granularity: Page, Action, Fragment. # # You can read more about each approach and the sweeping assistance by clicking the modules below. # # Note: To turn off all caching and sweeping, set Base.perform_caching = false. module Caching def self.included(base) #:nodoc: base.class_eval do include Pages, Actions, Fragments if defined? ActiveRecord include Sweeping, SqlCache end @@perform_caching = true cattr_accessor :perform_caching end end # Page caching is an approach to caching where the entire action output of is stored as a HTML file that the web server # can serve without going through the Action Pack. This can be as much as 100 times faster than going through the process of dynamically # generating the content. Unfortunately, this incredible speed-up is only available to stateless pages where all visitors # are treated the same. Content management systems -- including weblogs and wikis -- have many pages that are a great fit # for this approach, but account-based systems where people log in and manipulate their own data are often less likely candidates. # # Specifying which actions to cache is done through the caches class method: # # class WeblogController < ActionController::Base # caches_page :show, :new # end # # This will generate cache files such as weblog/show/5 and weblog/new, which match the URLs used to trigger the dynamic # generation. This is how the web server is able pick up a cache file when it exists and otherwise let the request pass on to # the Action Pack to generate it. # # Expiration of the cache is handled by deleting the cached file, which results in a lazy regeneration approach where the cache # is not restored before another hit is made against it. The API for doing so mimics the options from url_for and friends: # # class WeblogController < ActionController::Base # def update # List.update(params[:list][:id], params[:list]) # expire_page :action => "show", :id => params[:list][:id] # redirect_to :action => "show", :id => params[:list][:id] # end # end # # Additionally, you can expire caches using Sweepers that act on changes in the model to determine when a cache is supposed to be # expired. # # == Setting the cache directory # # The cache directory should be the document root for the web server and is set using Base.page_cache_directory = "/document/root". # For Rails, this directory has already been set to RAILS_ROOT + "/public". # # == Setting the cache extension # # By default, the cache extension is .html, which makes it easy for the cached files to be picked up by the web server. If you want # something else, like .php or .shtml, just set Base.page_cache_extension. module Pages def self.included(base) #:nodoc: base.extend(ClassMethods) base.class_eval do @@page_cache_directory = defined?(RAILS_ROOT) ? "#{RAILS_ROOT}/public" : "" cattr_accessor :page_cache_directory @@page_cache_extension = '.html' cattr_accessor :page_cache_extension end end module ClassMethods # Expires the page that was cached with the +path+ as a key. Example: # expire_page "/lists/show" def expire_page(path) return unless perform_caching benchmark "Expired page: #{page_cache_file(path)}" do File.delete(page_cache_path(path)) if File.exists?(page_cache_path(path)) end end # Manually cache the +content+ in the key determined by +path+. Example: # cache_page "I'm the cached content", "/lists/show" def cache_page(content, path) return unless perform_caching benchmark "Cached page: #{page_cache_file(path)}" do FileUtils.makedirs(File.dirname(page_cache_path(path))) File.open(page_cache_path(path), "wb+") { |f| f.write(content) } end end # Caches the +actions+ using the page-caching approach that'll store the cache in a path within the page_cache_directory that # matches the triggering url. def caches_page(*actions) return unless perform_caching actions = actions.map(&:to_s) after_filter { |c| c.cache_page if actions.include?(c.action_name) } end private def page_cache_file(path) name = ((path.empty? || path == "/") ? "/index" : URI.unescape(path)) name << page_cache_extension unless (name.split('/').last || name).include? '.' return name end def page_cache_path(path) page_cache_directory + page_cache_file(path) end end # Expires the page that was cached with the +options+ as a key. Example: # expire_page :controller => "lists", :action => "show" def expire_page(options = {}) return unless perform_caching if options.is_a?(Hash) if options[:action].is_a?(Array) options[:action].dup.each do |action| self.class.expire_page(url_for(options.merge(:only_path => true, :skip_relative_url_root => true, :action => action))) end else self.class.expire_page(url_for(options.merge(:only_path => true, :skip_relative_url_root => true))) end else self.class.expire_page(options) end end # Manually cache the +content+ in the key determined by +options+. If no content is provided, the contents of response.body is used # If no options are provided, the requested url is used. Example: # cache_page "I'm the cached content", :controller => "lists", :action => "show" def cache_page(content = nil, options = nil) return unless perform_caching && caching_allowed path = case options when Hash url_for(options.merge(:only_path => true, :skip_relative_url_root => true, :format => params[:format])) when String options else request.path end self.class.cache_page(content || response.body, path) end private def caching_allowed request.get? && response.headers['Status'].to_i == 200 end end # 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. http://david.somewhere.com/lists and http://david.somewhere.com/lists.xml # are treated like separate requests and so are cached separately. Keep in mind when expiring an action cache that :action => 'lists' is not the same # as :action => 'list', :format => :xml. # # 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 perform_caching around_filter(ActionCacheFilter.new(*actions)) end end def protected_instance_variables_with_action_caching protected_instance_variables_without_action_caching + %w(@action_cache_path) end def expire_action(options = {}) return unless perform_caching 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::EXTENSION_LOOKUP[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 # Fragment caching is used for caching various blocks within templates without caching the entire action as a whole. This is useful when # certain elements of an action change frequently or depend on complicated state while other parts rarely change or can be shared amongst multiple # parties. The caching is doing using the cache helper available in the Action View. A template with caching might look something like: # # Hello <%= @name %> # <% cache do %> # All the topics in the system: # <%= render :partial => "topic", :collection => Topic.find(:all) %> # <% end %> # # This cache will bind to the name of action that called it. So you would be able to invalidate it using # expire_fragment(:controller => "topics", :action => "list") -- if that was the controller/action used. This is not too helpful # if you need to cache multiple fragments per action or if the action itself is cached using caches_action. So instead we should # qualify the name of the action used with something like: # # <% cache(:action => "list", :action_suffix => "all_topics") do %> # # That would result in a name such as "/topics/list/all_topics", which wouldn't conflict with any action cache and neither with another # fragment using a different suffix. Note that the URL doesn't have to really exist or be callable. We're just using the url_for system # to generate unique cache names that we can refer to later for expirations. The expiration call for this example would be # expire_fragment(:controller => "topics", :action => "list", :action_suffix => "all_topics"). # # == Fragment stores # # In order to use the fragment caching, you need to designate where the caches should be stored. This is done by assigning a fragment store # of which there are four different kinds: # # * FileStore: Keeps the fragments on disk in the +cache_path+, which works well for all types of environments and shares the fragments for # all the web server processes running off the same application directory. # * MemoryStore: Keeps the fragments in memory, which is fine for WEBrick and for FCGI (if you don't care that each FCGI process holds its # own fragment store). It's not suitable for CGI as the process is thrown away at the end of each request. It can potentially also take # up a lot of memory since each process keeps all the caches in memory. # * DRbStore: Keeps the fragments in the memory of a separate, shared DRb process. This works for all environments and only keeps one cache # around for all processes, but requires that you run and manage a separate DRb process. # * MemCacheStore: Works like DRbStore, but uses Danga's MemCache instead. # Requires the ruby-memcache library: gem install ruby-memcache. # # Configuration examples (MemoryStore is the default): # # ActionController::Base.fragment_cache_store = :memory_store # ActionController::Base.fragment_cache_store = :file_store, "/path/to/cache/directory" # ActionController::Base.fragment_cache_store = :drb_store, "druby://localhost:9192" # ActionController::Base.fragment_cache_store = :mem_cache_store, "localhost" # ActionController::Base.fragment_cache_store = MyOwnStore.new("parameter") module Fragments def self.included(base) #:nodoc: base.class_eval do @@fragment_cache_store = MemoryStore.new cattr_reader :fragment_cache_store def self.fragment_cache_store=(store_option) store, *parameters = *([ store_option ].flatten) @@fragment_cache_store = if store.is_a?(Symbol) store_class_name = (store == :drb_store ? "DRbStore" : store.to_s.camelize) store_class = ActionController::Caching::Fragments.const_get(store_class_name) store_class.new(*parameters) else store end end end end def fragment_cache_key(name) name.is_a?(Hash) ? url_for(name).split("://").last : name end # Called by CacheHelper#cache def cache_erb_fragment(block, name = {}, options = nil) unless perform_caching then block.call; return end buffer = eval(ActionView::Base.erb_variable, block.binding) if cache = read_fragment(name, options) buffer.concat(cache) else pos = buffer.length block.call write_fragment(name, buffer[pos..-1], options) end end def write_fragment(name, content, options = nil) return unless perform_caching key = fragment_cache_key(name) self.class.benchmark "Cached fragment: #{key}" do fragment_cache_store.write(key, content, options) end content end def read_fragment(name, options = nil) return unless perform_caching key = fragment_cache_key(name) self.class.benchmark "Fragment read: #{key}" do fragment_cache_store.read(key, options) end end # Name can take one of three forms: # * String: This would normally take the form of a path like "pages/45/notes" # * Hash: Is treated as an implicit call to url_for, like { :controller => "pages", :action => "notes", :id => 45 } # * Regexp: Will destroy all the matched fragments, example: # %r{pages/\d*/notes} # Ensure you do not specify start and finish in the regex (^$) because # the actual filename matched looks like ./cache/filename/path.cache # Regexp expiration is not supported on caches which can't iterate over # all keys, such as memcached. def expire_fragment(name, options = nil) return unless perform_caching key = fragment_cache_key(name) if key.is_a?(Regexp) self.class.benchmark "Expired fragments matching: #{key.source}" do fragment_cache_store.delete_matched(key, options) end else self.class.benchmark "Expired fragment: #{key}" do fragment_cache_store.delete(key, options) end end end class UnthreadedMemoryStore #:nodoc: def initialize #:nodoc: @data = {} end def read(name, options=nil) #:nodoc: @data[name] end def write(name, value, options=nil) #:nodoc: @data[name] = value end def delete(name, options=nil) #:nodoc: @data.delete(name) end def delete_matched(matcher, options=nil) #:nodoc: @data.delete_if { |k,v| k =~ matcher } end end module ThreadSafety #:nodoc: def read(name, options=nil) #:nodoc: @mutex.synchronize { super } end def write(name, value, options=nil) #:nodoc: @mutex.synchronize { super } end def delete(name, options=nil) #:nodoc: @mutex.synchronize { super } end def delete_matched(matcher, options=nil) #:nodoc: @mutex.synchronize { super } end end class MemoryStore < UnthreadedMemoryStore #:nodoc: def initialize #:nodoc: super if ActionController::Base.allow_concurrency @mutex = Mutex.new MemoryStore.module_eval { include ThreadSafety } end end end class DRbStore < MemoryStore #:nodoc: attr_reader :address def initialize(address = 'druby://localhost:9192') super() @address = address @data = DRbObject.new(nil, address) end end begin require_library_or_gem 'memcache' class MemCacheStore < MemoryStore #:nodoc: attr_reader :addresses def initialize(*addresses) super() addresses = addresses.flatten addresses = ["localhost"] if addresses.empty? @addresses = addresses @data = MemCache.new(*addresses) end end rescue LoadError # MemCache wasn't available so neither can the store be end class UnthreadedFileStore #:nodoc: attr_reader :cache_path def initialize(cache_path) @cache_path = cache_path end def write(name, value, options = nil) #:nodoc: ensure_cache_path(File.dirname(real_file_path(name))) File.open(real_file_path(name), "wb+") { |f| f.write(value) } rescue => e Base.logger.error "Couldn't create cache directory: #{name} (#{e.message})" if Base.logger end def read(name, options = nil) #:nodoc: File.open(real_file_path(name), 'rb') { |f| f.read } rescue nil end def delete(name, options) #:nodoc: File.delete(real_file_path(name)) rescue SystemCallError => e # If there's no cache, then there's nothing to complain about end def delete_matched(matcher, options) #:nodoc: search_dir(@cache_path) do |f| if f =~ matcher begin File.delete(f) rescue SystemCallError => e # If there's no cache, then there's nothing to complain about end end end end private def real_file_path(name) '%s/%s.cache' % [@cache_path, name.gsub('?', '.').gsub(':', '.')] end def ensure_cache_path(path) FileUtils.makedirs(path) unless File.exists?(path) end def search_dir(dir, &callback) Dir.foreach(dir) do |d| next if d == "." || d == ".." name = File.join(dir, d) if File.directory?(name) search_dir(name, &callback) else callback.call name end end end end class FileStore < UnthreadedFileStore #:nodoc: def initialize(cache_path) super(cache_path) if ActionController::Base.allow_concurrency @mutex = Mutex.new FileStore.module_eval { include ThreadSafety } end end end end # Sweepers are the terminators of the caching world and responsible for expiring caches when model objects change. # They do this by being half-observers, half-filters and implementing callbacks for both roles. A Sweeper example: # # class ListSweeper < ActionController::Caching::Sweeper # observe List, Item # # def after_save(record) # list = record.is_a?(List) ? record : record.list # expire_page(:controller => "lists", :action => %w( show public feed ), :id => list.id) # expire_action(:controller => "lists", :action => "all") # list.shares.each { |share| expire_page(:controller => "lists", :action => "show", :id => share.url_key) } # end # end # # The sweeper is assigned in the controllers that wish to have its job performed using the cache_sweeper class method: # # class ListsController < ApplicationController # caches_action :index, :show, :public, :feed # cache_sweeper :list_sweeper, :only => [ :edit, :destroy, :share ] # end # # In the example above, four actions are cached and three actions are responsible for expiring those caches. module Sweeping def self.included(base) #:nodoc: base.extend(ClassMethods) end module ClassMethods #:nodoc: def cache_sweeper(*sweepers) return unless perform_caching configuration = sweepers.extract_options! sweepers.each do |sweeper| ActiveRecord::Base.observers << sweeper if defined?(ActiveRecord) and defined?(ActiveRecord::Base) sweeper_instance = Object.const_get(Inflector.classify(sweeper)).instance if sweeper_instance.is_a?(Sweeper) around_filter(sweeper_instance, :only => configuration[:only]) else after_filter(sweeper_instance, :only => configuration[:only]) end end end end end if defined?(ActiveRecord) and defined?(ActiveRecord::Observer) class Sweeper < ActiveRecord::Observer #:nodoc: attr_accessor :controller def before(controller) self.controller = controller callback(:before) end def after(controller) callback(:after) # Clean up, so that the controller can be collected after this request self.controller = nil end protected # gets the action cache path for the given options. def action_path_for(options) ActionController::Caching::Actions::ActionCachePath.path_for(controller, options) end # Retrieve instance variables set in the controller. def assigns(key) controller.instance_variable_get("@#{key}") end private def callback(timing) controller_callback_method_name = "#{timing}_#{controller.controller_name.underscore}" action_callback_method_name = "#{controller_callback_method_name}_#{controller.action_name}" send!(controller_callback_method_name) if respond_to?(controller_callback_method_name, true) send!(action_callback_method_name) if respond_to?(action_callback_method_name, true) end def method_missing(method, *arguments) return if @controller.nil? @controller.send!(method, *arguments) end end end module SqlCache def self.included(base) #:nodoc: if defined?(ActiveRecord) && ActiveRecord::Base.respond_to?(:cache) base.alias_method_chain :perform_action, :caching end end def perform_action_with_caching ActiveRecord::Base.cache do perform_action_without_caching end end end end end