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Module: ActiveSupport::Cache

Overview

See Store for documentation.

Constant Summary

Class Attribute Summary

Class Method Summary

Class Attribute Details

.format_version (rw)

[ GitHub ]

  
# File 'activesupport/lib/active_support/cache.rb', line 58

attr_accessor :format_version

Class Method Details

.expand_cache_key(key, namespace = nil)

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.

[ GitHub ]

  
# File 'activesupport/lib/active_support/cache.rb', line 111

def expand_cache_key(key, namespace = nil)
  expanded_cache_key = namespace ? +"#{namespace}/" : +""

  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 = nil, *parameters)

Creates a new Cache::Store object according to the given options.

If no arguments are passed to this method, then a new Cache::MemoryStore object will be returned.

If you pass a ::Symbol as the first argument, then a corresponding cache store class under the 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
[ GitHub ]

  
# File 'activesupport/lib/active_support/cache.rb', line 85

def lookup_store(store = nil, *parameters)
  case store
  when Symbol
    options = parameters.extract_options!
    retrieve_store_class(store).new(*parameters, **options)
  when Array
    lookup_store(*store)
  when nil
    ActiveSupport::Cache::MemoryStore.new
  else
    store
  end
end

.retrieve_cache_key(key) (private)

[ GitHub ]

  
# File 'activesupport/lib/active_support/cache.rb', line 123

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) (private)

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

[ GitHub ]

  
# File 'activesupport/lib/active_support/cache.rb', line 135

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