class Ramaze::Cache::MemCache
Cache driver for the Memcache storage engine. Memcache is a key/value store that's extremely useful for caching data such as views or API responses. More inforamtion about Memcache can be found on it's website: <memcached.org/>.
Note that this cache driver requires the Dalli gem rather than Memcache Client. The reason for this is that the Memcache client hasn't been updated in over a year and Memcache has changed quite a bit. Dalli is also supposed to be faster and better coded. This cache driver will also try to load the kgio Gem if it's installed, if it's not it will just continue to operate but you won't get the nice speed boost.
This driver works similar to Ramaze::Cache::Sequel in that it allows you to specify instance specific options uisng the using() method:
Ramaze::Cache.options.session = Ramaze::Cache::MemCache.using( :compression => false )
All options sent to the using() method will be sent to Dalli.
@example Using the default options
Ramaze::Cache.options.view = Ramaze::Cache::MemCache Ramaze.setup_dependencies Ramaze::Cache.view.store(:my_view, 'Hello Ramaze')
@example Using custom options
Ramaze::Cache.options.view = Ramaze::Cache::MemCache.using( :compression => false, :servers => ['localhost:11211', 'localhost:112112'] ) Ramaze.setup_dependencies Ramaze::Cache.view.store(:my_view, 'Hello Ramaze')
@author Yorick Peterse @since 04-05-2011
Constants
- MAX_TTL
The maximum Time To Live that can be used in Memcache
Attributes
Hash containing all the default options merged with the user specified ones
Public Class Methods
Creates a new instance of the cache class.
@author Michael Fellinger @since 04-05-2011 @param [Hash] options A hash with custom options, see
Ramaze::Cache::MemCache.using for all available options.
# File lib/ramaze/cache/memcache.rb, line 116 def initialize(options = {}) self.class.options ||= Ramaze::Cache::MemCache.trait[:default].merge( options ) @options = options.merge(self.class.options) end
This method will create a subclass of Ramaze::Cache::MemCache with all the custom options set. All options set in this method will be sent to Dalli as well.
Using this method allows you to use different memcache settings for various parts of Ramaze. For example, you might want to use servers A and B for storing the sessions but server C for only views. Most of the way this method works was inspired by Ramaze::Cache::Sequel which was contributed by Lars Olsson.
@example
Ramaze::Cache.options.session = Ramaze::Cache::MemCache.using( :compression => false, :username => 'ramaze', :password => 'ramaze123', :servers => ['othermachine.com:12345'] )
@author Yorick Peterse @since 04-05-2011 @param [Hash] options A hash containing all configuration options to
use for Dalli. For more information on all the available options you can read the README in their repository. This repository can be found here: https://github.com/mperham/dalli
# File lib/ramaze/cache/memcache.rb, line 102 def using(options = {}) merged = Ramaze::Cache::MemCache.trait[:default].merge(options) Class.new(self) { @options = merged } end
Public Instance Methods
Removes all items from the cache.
@author Yorick Peterse @since 04-05-2011
# File lib/ramaze/cache/memcache.rb, line 155 def cache_clear @client.flush end
Removes the specified keys from the cache.
@author Yorick Peterse @since 04-05-2011 @param [Array] keys The keys to remove from the cache.
# File lib/ramaze/cache/memcache.rb, line 166 def cache_delete(*keys) keys.each do |key| @client.delete(key) end end
Fetches the specified key from the cache. It the value was nil the default value will be returned instead.
@author Yorick Peterse @since 04-05-2011 @param [String] key The name of the key to retrieve. @param [Mixed] default The default value. @return [Mixed]
# File lib/ramaze/cache/memcache.rb, line 182 def cache_fetch(key, default = nil) value = @client.get(key) if value.nil? return default else return value end end
Prepares the cache by creating the namespace and an instance of a Dalli client.
@author Yorick Peterse @since 04-05-2011 @param [String] hostname The hostname of the machine running the
application.
@param [String] username The name of the user executing the process @param [String] appname Unique identifier for the application. @param [String] cachename The namespace to use for this cache instance.
# File lib/ramaze/cache/memcache.rb, line 136 def cache_setup(hostname, username, appname, cachename) # Validate the maximum TTL if options[:expires_in] > MAX_TTL raise(ArgumentError, "The maximum TTL of Memcache is 30 days") end options[:namespace] = [ hostname, username, appname, cachename ].compact.join('-') @client = ::Dalli::Client.new(options[:servers], options) end
Sets the given key to the specified value. Optionally you can specify a hash with options specific to the key. Once a key has been stored it's value will be returned.
@author Yorick Peterse @since 04-05-2011 @param [String] key The name of the key to store. @param [Mixed] value The value to store in Memcache. @param [Fixnum] ttl The Time To Live to use for the current key. @param [Hash] options A hash containing options specific for the
specified key.
@return [Mixed]
# File lib/ramaze/cache/memcache.rb, line 206 def cache_store(key, value, ttl = nil, options = {}) ttl = options.delete(:ttl) || @options[:expires_in] if ttl > MAX_TTL raise(ArgumentError, "The maximum TTL of Memcache is 30 days") end @client.set(key, value, ttl, options) return value end