A cache store implementation which stores data in Memcached: 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.

Methods
B
C
N
R
S
Classes and Modules
Constants
ESCAPE_KEY_CHARS = /[\x00-\x20%\x7F-\xFF]/n
Class Public methods
build_mem_cache(*addresses)

Source: show | on GitHub 

    # File activesupport/lib/active_support/cache/mem_cache_store.rb, line 36
36:       def self.build_mem_cache(*addresses)
37:         addresses = addresses.flatten
38:         options = addresses.extract_options!
39:         addresses = ["localhost:11211"] if addresses.empty?
40:         MemCache.new(addresses, options)
41:       end
new(*addresses)

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).

Instead of addresses one can pass in a MemCache-like object. For example: 

  require 'memcached' # gem install memcached; uses C bindings to libmemcached
  ActiveSupport::Cache::MemCacheStore.new(Memcached::Rails.new("localhost:11211"))

Source: show | on GitHub 

    # File activesupport/lib/active_support/cache/mem_cache_store.rb, line 56
56:       def initialize(*addresses)
57:         addresses = addresses.flatten
58:         options = addresses.extract_options!
59:         super(options)
60: 
61:         if addresses.first.respond_to?(:get)
62:           @data = addresses.first
63:         else
64:           mem_cache_options = options.dup
65:           UNIVERSAL_OPTIONS.each{|name| mem_cache_options.delete(name)}
66:           @data = self.class.build_mem_cache(*(addresses + [mem_cache_options]))
67:         end
68: 
69:         extend Strategy::LocalCache
70:         extend LocalCacheWithRaw
71:       end
Instance Public methods
clear(options = nil)

Clear the entire cache on all memcached servers. This method should be used with care when shared cache is being used.

Source: show | on GitHub 

     # File activesupport/lib/active_support/cache/mem_cache_store.rb, line 118
118:       def clear(options = nil)
119:         @data.flush_all
120:       end
read_multi(*names)

Reads multiple values from the cache using a single call to the servers for all keys. Options can be passed in the last argument.

Source: show | on GitHub 

    # File activesupport/lib/active_support/cache/mem_cache_store.rb, line 75
75:       def read_multi(*names)
76:         options = names.extract_options!
77:         options = merged_options(options)
78:         keys_to_names = Hash[names.map{|name| [escape_key(namespaced_key(name, options)), name]}]
79:         raw_values = @data.get_multi(keys_to_names.keys, :raw => true)
80:         values = {}
81:         raw_values.each do |key, value|
82:           entry = deserialize_entry(value)
83:           values[keys_to_names[key]] = entry.value unless entry.expired?
84:         end
85:         values
86:       end
stats()

Get the statistics from the memcached servers.

Source: show | on GitHub 

     # File activesupport/lib/active_support/cache/mem_cache_store.rb, line 123
123:       def stats
124:         @data.stats
125:       end