Rails源代码分析（17）：ActionController::Caching(1)

1 框架

Cache可以很方便的来加速应用，可以在计算、rendering以及数据库调用

ActionController有3种方式的cache：

Page, Action, Fragment

To turn off all caching and sweeping, set Base.perform_caching = false.

Configuration examples (MemoryStore is the default):

  #   ActionController::Base.cache_store = :memory_store

  #   ActionController::Base.cache_store = :file_store, "/path/to/cache/directory"

  #   ActionController::Base.cache_store = :drb_store, "druby://localhost:9192"

  #   ActionController::Base.cache_store = :mem_cache_store, "localhost"

  #   ActionController::Base.cache_store = MyOwnStore.new("parameter")

1.   module Caching
2.     def self.included(base) #:nodoc:
3.       base.class_eval do
4.         @@cache_store = nil
5.         cattr_reader :cache_store
7.         # Defines the storage option for cached fragments
8.         # 
9.         def self.cache_store=(store_option)
10.           @@cache_store = ActiveSupport::Cache.lookup_store(store_option)
11.         end
13.         include Pages, Actions, Fragments
14.         include Sweeping, SqlCache if defined?(ActiveRecord)
16.         @@perform_caching = true
17.         cattr_accessor :perform_caching
19.         # 是否配置了cache，取决于 perform_caching 和 cache_store 设置了
20.        def self.cache_configured?
21.           perform_caching && cache_store
22.         end
23.       end
24.     end
26.     protected
27.       # Convenience accessor
28.       def cache(key, options = {}, &block)
29.         if cache_configured?
30.           cache_store.fetch(ActiveSupport::Cache.expand_cache_key(key, :controller), options, &block)
31.         else
32.           yield
33.         end
34.       end
37.     private    
38.       def cache_configured?
39.         self.class.cache_configured?
40.       end
41.   end