A cache store implementation which stores data in Memcached: www.danga.com/memcached/
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 goes back online.
- Time-based expiry support. See write and the +:expires_in+ option.
- Per-request in memory cache for all communication with the MemCache server(s).
Methods
Public Class methods
[ show source ]
# File activesupport/lib/active_support/cache/mem_cache_store.rb, line 26 26: def self.build_mem_cache(*addresses) 27: addresses = addresses.flatten 28: options = addresses.extract_options! 29: addresses = ["localhost"] if addresses.empty? 30: MemCache.new(addresses, options) 31: 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).
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"))
[ show source ]
# File activesupport/lib/active_support/cache/mem_cache_store.rb, line 46 46: def initialize(*addresses) 47: if addresses.first.respond_to?(:get) 48: @data = addresses.first 49: else 50: @data = self.class.build_mem_cache(*addresses) 51: end 52: 53: extend Strategy::LocalCache 54: end
Public Instance methods
[ show source ]
# File activesupport/lib/active_support/cache/mem_cache_store.rb, line 129 129: def clear 130: @data.flush_all 131: end
Reads multiple keys from the cache.
[ show source ]
# File activesupport/lib/active_support/cache/mem_cache_store.rb, line 57 57: def read_multi(*keys) 58: @data.get_multi keys 59: end
[ show source ]
# File activesupport/lib/active_support/cache/mem_cache_store.rb, line 133 133: def stats 134: @data.stats 135: end
Writes a value to the cache.
Possible options:
- +:unless_exist+ - set to true if you don‘t want to update the cache if the key is already set.
- +:expires_in+ - the number of seconds that this value may stay in the cache. See ActiveSupport::Cache::Store#write for an example.
[ show source ]
# File activesupport/lib/active_support/cache/mem_cache_store.rb, line 76 76: def write(key, value, options = nil) 77: super 78: method = options && options[:unless_exist] ? :add : :set 79: # memcache-client will break the connection if you send it an integer 80: # in raw mode, so we convert it to a string to be sure it continues working. 81: value = value.to_s if raw?(options) 82: response = @data.send(method, key, value, expires_in(options), raw?(options)) 83: response == Response::STORED 84: rescue MemCache::MemCacheError => e 85: logger.error("MemCacheError (#{e}): #{e.message}") 86: false 87: end