Skip to content
This repository
tree: b08c968875
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 229 lines (205 sloc) 8.006 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228
require 'benchmark'

module ActiveSupport
  # See ActiveSupport::Cache::Store for documentation.
  module Cache
    autoload :FileStore, 'active_support/cache/file_store'
    autoload :MemoryStore, 'active_support/cache/memory_store'
    autoload :SynchronizedMemoryStore, 'active_support/cache/synchronized_memory_store'
    autoload :DRbStore, 'active_support/cache/drb_store'
    autoload :MemCacheStore, 'active_support/cache/mem_cache_store'
    autoload :CompressedMemCacheStore, 'active_support/cache/compressed_mem_cache_store'

    module Strategy
      autoload :LocalCache, 'active_support/cache/strategy/local_cache'
    end

    # Creates a new CacheStore object according to the given options.
    #
    # If no arguments are passed to this method, then a new
    # ActiveSupport::Cache::MemoryStore object will be returned.
    #
    # If you pass a Symbol as the first argument, then a corresponding cache
    # store class under the ActiveSupport::Cache namespace will be created.
    # For example:
    #
    # ActiveSupport::Cache.lookup_store(:memory_store)
    # # => returns a new ActiveSupport::Cache::MemoryStore object
    #
    # ActiveSupport::Cache.lookup_store(:drb_store)
    # # => returns a new ActiveSupport::Cache::DRbStore object
    #
    # Any additional arguments will be passed to the corresponding cache store
    # class's constructor:
    #
    # ActiveSupport::Cache.lookup_store(:file_store, "/tmp/cache")
    # # => same as: ActiveSupport::Cache::FileStore.new("/tmp/cache")
    #
    # If the first argument is not a Symbol, then it will simply be returned:
    #
    # ActiveSupport::Cache.lookup_store(MyOwnCacheStore.new)
    # # => returns MyOwnCacheStore.new
    def self.lookup_store(*store_option)
      store, *parameters = *([ store_option ].flatten)

      case store
      when Symbol
        store_class_name = (store == :drb_store ? "DRbStore" : store.to_s.camelize)
        store_class = ActiveSupport::Cache.const_get(store_class_name)
        store_class.new(*parameters)
      when nil
        ActiveSupport::Cache::MemoryStore.new
      else
        store
      end
    end

    def self.expand_cache_key(key, namespace = nil)
      expanded_cache_key = namespace ? "#{namespace}/" : ""

      if ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"]
        expanded_cache_key << "#{ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"]}/"
      end

      expanded_cache_key << case
        when key.respond_to?(:cache_key)
          key.cache_key
        when key.is_a?(Array)
          key.collect { |element| expand_cache_key(element) }.to_param
        when key
          key.to_param
        end.to_s

      expanded_cache_key
    end

    # An abstract cache store class. There are multiple cache store
    # implementations, each having its own additional features. See the classes
    # under the ActiveSupport::Cache module, e.g.
    # ActiveSupport::Cache::MemCacheStore. MemCacheStore is currently the most
    # popular cache store for large production websites.
    #
    # ActiveSupport::Cache::Store is meant for caching strings. Some cache
    # store implementations, like MemoryStore, are able to cache arbitrary
    # Ruby objects, but don't count on every cache store to be able to do that.
    #
    # cache = ActiveSupport::Cache::MemoryStore.new
    #
    # cache.read("city") # => nil
    # cache.write("city", "Duckburgh")
    # cache.read("city") # => "Duckburgh"
    class Store
      cattr_accessor :logger

      def silence!
        @silence = true
        self
      end

      # Fetches data from the cache, using the given key. If there is data in
      # the cache with the given key, then that data is returned.
      #
      # If there is no such data in the cache (a cache miss occurred), then
      # then nil will be returned. However, if a block has been passed, then
      # that block will be run in the event of a cache miss. The return value
      # of the block will be written to the cache under the given cache key,
      # and that return value will be returned.
      #
      # cache.write("today", "Monday")
      # cache.fetch("today") # => "Monday"
      #
      # cache.fetch("city") # => nil
      # cache.fetch("city") do
      # "Duckburgh"
      # end
      # cache.fetch("city") # => "Duckburgh"
      #
      # You may also specify additional options via the +options+ argument.
      # Setting <tt>:force => true</tt> will force a cache miss:
      #
      # cache.write("today", "Monday")
      # cache.fetch("today", :force => true) # => nil
      #
      # Other options will be handled by the specific cache store implementation.
      # Internally, #fetch calls #read, and calls #write on a cache miss.
      # +options+ will be passed to the #read and #write calls.
      #
      # For example, MemCacheStore's #write method supports the +:expires_in+
      # option, which tells the memcached server to automatically expire the
      # cache item after a certain period. We can use this option with #fetch
      # too:
      #
      # cache = ActiveSupport::Cache::MemCacheStore.new
      # cache.fetch("foo", :force => true, :expires_in => 5.seconds) do
      # "bar"
      # end
      # cache.fetch("foo") # => "bar"
      # sleep(6)
      # cache.fetch("foo") # => nil
      def fetch(key, options = {})
        @logger_off = true
        if !options[:force] && value = read(key, options)
          @logger_off = false
          log("hit", key, options)
          value
        elsif block_given?
          @logger_off = false
          log("miss", key, options)

          value = nil
          ms = Benchmark.ms { value = yield }

          @logger_off = true
          write(key, value, options)
          @logger_off = false

          log('write (will save %.2fms)' % ms, key, nil)

          value
        end
      end

      # Fetches data from the cache, using the given key. If there is data in
      # the cache with the given key, then that data is returned. Otherwise,
      # nil is returned.
      #
      # You may also specify additional options via the +options+ argument.
      # The specific cache store implementation will decide what to do with
      # +options+.
      def read(key, options = nil)
        log("read", key, options)
      end

      # Writes the given value to the cache, with the given key.
      #
      # You may also specify additional options via the +options+ argument.
      # The specific cache store implementation will decide what to do with
      # +options+.
      #
      # For example, MemCacheStore supports the +:expires_in+ option, which
      # tells the memcached server to automatically expire the cache item after
      # a certain period:
      #
      # cache = ActiveSupport::Cache::MemCacheStore.new
      # cache.write("foo", "bar", :expires_in => 5.seconds)
      # cache.read("foo") # => "bar"
      # sleep(6)
      # cache.read("foo") # => nil
      def write(key, value, options = nil)
        log("write", key, options)
      end

      def delete(key, options = nil)
        log("delete", key, options)
      end

      def delete_matched(matcher, options = nil)
        log("delete matched", matcher.inspect, options)
      end

      def exist?(key, options = nil)
        log("exist?", key, options)
      end

      def increment(key, amount = 1)
        log("incrementing", key, amount)
        if num = read(key)
          write(key, num + amount)
        else
          nil
        end
      end

      def decrement(key, amount = 1)
        log("decrementing", key, amount)
        if num = read(key)
          write(key, num - amount)
        else
          nil
        end
      end

      private
        def log(operation, key, options)
          logger.debug("Cache #{operation}: #{key}#{options ? " (#{options.inspect})" : ""}") if logger && !@silence && !@logger_off
        end
    end
  end
end
Something went wrong with that request. Please try again.