Module: ActiveSupport::Cache

Relationships & Source Files
Namespace Children
Modules: `SerializerWithFallback`, `Strategy`
Classes: `Coder`, `FileStore`, `MemCacheStore`, `MemoryStore`, `NullStore`, `RedisCacheStore`, `Store`, `WriteOptions`
Defined in:	activesupport/lib/active_support/cache.rb, activesupport/lib/active_support/cache/coder.rb, activesupport/lib/active_support/cache/entry.rb, activesupport/lib/active_support/cache/file_store.rb, activesupport/lib/active_support/cache/mem_cache_store.rb, activesupport/lib/active_support/cache/memory_store.rb, activesupport/lib/active_support/cache/null_store.rb, activesupport/lib/active_support/cache/redis_cache_store.rb, activesupport/lib/active_support/cache/serializer_with_fallback.rb, activesupport/lib/active_support/cache/strategy/local_cache.rb, activesupport/lib/active_support/cache/strategy/local_cache_middleware.rb

Overview

See Store for documentation.

Constant Summary

DEFAULT_COMPRESS_LIMIT =
# File 'activesupport/lib/active_support/cache.rb', line 45
```
1.kilobyte
```
DeserializationError =

Raised by coders when the cache entry can’t be deserialized. This error is treated as a cache miss.

# File 'activesupport/lib/active_support/cache.rb', line 49
```
Class.new(StandardError)
```
OPTION_ALIASES =

Mapping of canonical option names to aliases that a store will recognize.

# File 'activesupport/lib/active_support/cache.rb', line 41
```
{
  expires_in: [:expire_in, :expired_in]
}.freeze
```

UNIVERSAL_OPTIONS =

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

# File 'activesupport/lib/active_support/cache.rb', line 26

[
  :coder,
  :compress,
  :compress_threshold,
  :compressor,
  :expire_in,
  :expired_in,
  :expires_in,
  :namespace,
  :race_condition_ttl,
  :serializer,
  :skip_nil,
]

Class Attribute Summary

.format_version rw

Class Method Summary

.expand_cache_key(key, namespace = nil)

Expands out the key argument into a key that can be used for the cache store.
.lookup_store(store = nil, *parameters)

Creates a new Store object according to the given options.

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 117


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!
    # clean this up once Ruby 2.7 support is dropped
    # see https://github.com/rails/rails/pull/41522#discussion_r581186602
    if options.empty?
      retrieve_store_class(store).new(*parameters)
    else
      retrieve_store_class(store).new(*parameters, **options)
    end
  when Array
    lookup_store(*store)
  when nil
    ActiveSupport::Cache::MemoryStore.new
  else
    store
  end
end