begin require 'dalli' rescue LoadError => e $stderr.puts "You don't have dalli installed in your application. Please add it to your Gemfile and run bundle install" raise e end require 'digest/md5' require 'active_support/core_ext/marshal' require 'active_support/core_ext/array/extract_options' module ActiveSupport module Cache # A cache store implementation which stores data in Memcached: # http://memcached.org/ # # This is currently the most popular cache store for production websites. # # Special features: # - Clustering and load balancing. One can specify multiple memcached servers, # and MemCacheStore will load balance between all available servers. If a # server goes down, then MemCacheStore will ignore it until it comes back up. # # MemCacheStore implements the Strategy::LocalCache strategy which implements # an in-memory cache inside of a block. class MemCacheStore < Store # Provide support for raw values in the local cache strategy. module LocalCacheWithRaw # :nodoc: protected def read_entry(key, options) entry = super if options[:raw] && local_cache && entry entry = deserialize_entry(entry.value) end entry end def write_entry(key, entry, options) # :nodoc: if options[:raw] && local_cache raw_entry = Entry.new(entry.value.to_s) raw_entry.expires_at = entry.expires_at super(key, raw_entry, options) else super end end end prepend Strategy::LocalCache prepend LocalCacheWithRaw ESCAPE_KEY_CHARS = /[\x00-\x20%\x7F-\xFF]/n # Creates a new Dalli::Client instance with specified addresses and options. # By default address is equal localhost:11211. # # ActiveSupport::Cache::MemCacheStore.build_mem_cache # # => # # ActiveSupport::Cache::MemCacheStore.build_mem_cache('localhost:10290') # # => # def self.build_mem_cache(*addresses) # :nodoc: addresses = addresses.flatten options = addresses.extract_options! addresses = ["localhost:11211"] if addresses.empty? Dalli::Client.new(addresses, options) end # Creates a new MemCacheStore object, with the given memcached server # addresses. Each address is either a host name, or a host-with-port string # in the form of "host_name:port". For example: # # ActiveSupport::Cache::MemCacheStore.new("localhost", "server-downstairs.localnetwork:8229") # # If no addresses are specified, then MemCacheStore will connect to # localhost port 11211 (the default memcached port). def initialize(*addresses) addresses = addresses.flatten options = addresses.extract_options! super(options) unless [String, Dalli::Client, NilClass].include?(addresses.first.class) raise ArgumentError, "First argument must be an empty array, an array of hosts or a Dalli::Client instance." end if addresses.first.is_a?(Dalli::Client) @data = addresses.first else mem_cache_options = options.dup UNIVERSAL_OPTIONS.each{|name| mem_cache_options.delete(name)} @data = self.class.build_mem_cache(*(addresses + [mem_cache_options])) end end # Reads multiple values from the cache using a single call to the # servers for all keys. Options can be passed in the last argument. def read_multi(*names) options = names.extract_options! options = merged_options(options) instrument_multi(:read, names, options) do keys_to_names = Hash[names.map{|name| [normalize_key(name, options), name]}] raw_values = @data.get_multi(keys_to_names.keys, :raw => true) values = {} raw_values.each do |key, value| entry = deserialize_entry(value) values[keys_to_names[key]] = entry.value unless entry.expired? end values end end # Increment a cached value. This method uses the memcached incr atomic # operator and can only be used on values written with the :raw option. # Calling it on a value not stored with :raw will initialize that value # to zero. def increment(name, amount = 1, options = nil) # :nodoc: options = merged_options(options) instrument(:increment, name, :amount => amount) do rescue_error_with nil do @data.incr(normalize_key(name, options), amount) end end end # Decrement a cached value. This method uses the memcached decr atomic # operator and can only be used on values written with the :raw option. # Calling it on a value not stored with :raw will initialize that value # to zero. def decrement(name, amount = 1, options = nil) # :nodoc: options = merged_options(options) instrument(:decrement, name, :amount => amount) do rescue_error_with nil do @data.decr(normalize_key(name, options), amount) end end end # Clear the entire cache on all memcached servers. This method should # be used with care when shared cache is being used. def clear(options = nil) rescue_error_with(nil) { @data.flush_all } end # Get the statistics from the memcached servers. def stats @data.stats end protected # Read an entry from the cache. def read_entry(key, options) # :nodoc: rescue_error_with(nil) { deserialize_entry(@data.get(key, options)) } end # Write an entry to the cache. def write_entry(key, entry, options) # :nodoc: method = options && options[:unless_exist] ? :add : :set value = options[:raw] ? entry.value.to_s : entry expires_in = options[:expires_in].to_i if expires_in > 0 && !options[:raw] # Set the memcache expire a few minutes in the future to support race condition ttls on read expires_in += 5.minutes end rescue_error_with false do @data.send(method, key, value, expires_in, options) end end # Delete an entry from the cache. def delete_entry(key, options) # :nodoc: rescue_error_with(false) { @data.delete(key) } end private # Memcache keys are binaries. So we need to force their encoding to binary # before applying the regular expression to ensure we are escaping all # characters properly. def normalize_key(key, options) key = super.dup key = key.force_encoding(Encoding::ASCII_8BIT) key = key.gsub(ESCAPE_KEY_CHARS){ |match| "%#{match.getbyte(0).to_s(16).upcase}" } key = "#{key[0, 213]}:md5:#{Digest::MD5.hexdigest(key)}" if key.size > 250 key end def escape_key(key) ActiveSupport::Deprecation.warn(<<-MESSAGE.strip_heredoc) `escape_key` is deprecated and will be removed from Rails 5.1. Please use `normalize_key` which will return a fully resolved key or nothing. MESSAGE key end def deserialize_entry(raw_value) if raw_value entry = Marshal.load(raw_value) rescue raw_value entry.is_a?(Entry) ? entry : Entry.new(entry) end end def rescue_error_with(fallback) yield rescue Dalli::DalliError => e logger.error("DalliError (#{e}): #{e.message}") if logger fallback end end end end