module ActiveSupport::Cache

See ActiveSupport::Cache::Store for documentation.

Constants

UNIVERSAL_OPTIONS

These options mean something to all cache implementations. Individual cache implementations may support additional options.

Public Class Methods

expand_cache_key(key, namespace = nil) click to toggle source

Expands out the key argument into a key that can be used for the cache store. Optionally accepts a namespace, and all keys will be scoped within that namespace.

If the key argument provided is an array, or responds to to_a, then each of elements in the array will be turned into parameters/keys and concatenated into a single key. For example:

ActiveSupport::Cache.expand_cache_key([:foo, :bar])               # => "foo/bar"
ActiveSupport::Cache.expand_cache_key([:foo, :bar], "namespace")  # => "namespace/foo/bar"

The key argument can also respond to cache_key or to_param.

# File lib/active_support/cache.rb, line 80
def expand_cache_key(key, namespace = nil)
  expanded_cache_key = (namespace ? "#{namespace}/" : "").dup

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

  expanded_cache_key << retrieve_cache_key(key)
  expanded_cache_key
end
lookup_store(*store_option) click to toggle source

Creates a new Store 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(:mem_cache_store)
# => returns a new ActiveSupport::Cache::MemCacheStore 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
# File lib/active_support/cache.rb, line 55
def lookup_store(*store_option)
  store, *parameters = *Array.wrap(store_option).flatten

  case store
  when Symbol
    retrieve_store_class(store).new(*parameters)
  when nil
    ActiveSupport::Cache::MemoryStore.new
  else
    store
  end
end

Private Class Methods

retrieve_cache_key(key) click to toggle source
# File lib/active_support/cache.rb, line 92
def retrieve_cache_key(key)
  case
  when key.respond_to?(:cache_key_with_version) then key.cache_key_with_version
  when key.respond_to?(:cache_key)              then key.cache_key
  when key.is_a?(Array)                         then key.map { |element| retrieve_cache_key(element) }.to_param
  when key.respond_to?(:to_a)                   then retrieve_cache_key(key.to_a)
  else                                               key.to_param
  end.to_s
end
retrieve_store_class(store) click to toggle source

Obtains the specified cache store class, given the name of the store. Raises an error when the store class cannot be found.

# File lib/active_support/cache.rb, line 104
def retrieve_store_class(store)
  # require_relative cannot be used here because the class might be
  # provided by another gem, like redis-activesupport for example.
  require "active_support/cache/#{store}"
rescue LoadError => e
  raise "Could not find cache store adapter for #{store} (#{e})"
else
  ActiveSupport::Cache.const_get(store.to_s.camelize)
end