vendor/rails/actionpack/lib/action_controller/caching.rb

   1 require 'fileutils'
   2 require 'uri'
   3 require 'set'
   4
   5 module ActionController #:nodoc:
   6   # Caching is a cheap way of speeding up slow applications by keeping the result of calculations, renderings, and database calls
   7   # around for subsequent requests. Action Controller affords you three approaches in varying levels of granularity: Page, Action, Fragment.
   8   #
   9   # You can read more about each approach and the sweeping assistance by clicking the modules below.
  10   #
  11   # Note: To turn off all caching and sweeping, set Base.perform_caching = false.
  12   #
  13   #
  14   # == Caching stores
  15   #
  16   # All the caching stores from ActiveSupport::Cache is available to be used as backends for Action Controller caching. This setting only
  17   # affects action and fragment caching as page caching is always written to disk.
  18   #
  19   # Configuration examples (MemoryStore is the default):
  20   #
  21   #   ActionController::Base.cache_store = :memory_store
  22   #   ActionController::Base.cache_store = :file_store, "/path/to/cache/directory"
  23   #   ActionController::Base.cache_store = :drb_store, "druby://localhost:9192"
  24   #   ActionController::Base.cache_store = :mem_cache_store, "localhost"
  25   #   ActionController::Base.cache_store = MyOwnStore.new("parameter")
  26   module Caching
  27     autoload :Actions, 'action_controller/caching/actions'
  28     autoload :Fragments, 'action_controller/caching/fragments'
  29     autoload :Pages, 'action_controller/caching/pages'
  30     autoload :Sweeper, 'action_controller/caching/sweeping'
  31     autoload :Sweeping, 'action_controller/caching/sweeping'
  32
  33     def self.included(base) #:nodoc:
  34       base.class_eval do
  35         @@cache_store = nil
  36         cattr_reader :cache_store
  37
  38         # Defines the storage option for cached fragments
  39         def self.cache_store=(store_option)
  40           @@cache_store = ActiveSupport::Cache.lookup_store(store_option)
  41         end
  42
  43         include Pages, Actions, Fragments
  44         include Sweeping if defined?(ActiveRecord)
  45
  46         @@perform_caching = true
  47         cattr_accessor :perform_caching
  48
  49         def self.cache_configured?
  50           perform_caching && cache_store
  51         end
  52       end
  53     end
  54
  55     protected
  56       # Convenience accessor
  57       def cache(key, options = {}, &block)
  58         if cache_configured?
  59           cache_store.fetch(ActiveSupport::Cache.expand_cache_key(key, :controller), options, &block)
  60         else
  61           yield
  62         end
  63       end
  64
  65     private
  66       def cache_configured?
  67         self.class.cache_configured?
  68       end
  69   end
  70 end