bucketcache.backends¶

class bucketcache.backends.Backend(value, expiration_date=None, config=None)[source]¶

Bases: represent.core.ReprMixin, object

Abstract base class for backends.

Classes must implement abstract attributes:

• binary_format
• default_config
• file_extension

and abstract methods:

• dump()
• from_file()

binary_format¶

Return True or False to indicate if files should be opened in binary mode before passing to from_file() and dump().

default_config¶

Associated bucketcache.config.Config class. Instantiated without arguments to create default configuration.

file_extension¶

File extension (without full stop) for files created by the backend.

classmethod check_concrete(skip_methods=False)[source]¶

Verify that we’re a concrete class.

Check that abstract methods have been overridden, and verify that abstract class attributes exist.

Although ABCMeta checks the abstract methods on instantiation, we can also do this here to ensure the given Backend is valid when the Bucket is created.

classmethod valid_config(config)[source]¶

Verify passed config, or return default_config.

has_expired()[source]¶

Determine if value held by this instance has expired.

Returns False if object does not expire.

classmethod from_file(fp, config=None)[source]¶

Class method for instantiating from file.

Parameters:	fp (file-like object) – File containing stored data. config (Config) – Configuration passed from Bucket

Note

Implementations should ensure config is valid as follows:

config = cls.valid_config(config)

Warning

If the appropriate data cannot be ready from fp, this method should raise BackendLoadError to inform Bucket that this cached file cannot be used.

dump(fp)[source]¶

Called to save state to file.

Parameters:	fp (file-like object) – File to contain stored data.

Attributes value and expiration_date should be saved, so that from_file() can use them.

class bucketcache.backends.PickleBackend(value, expiration_date=None, config=None)[source]¶

Bases: bucketcache.backends.Backend

Backend that serializes objects using Pickle.

default_config¶

alias of PickleConfig

class bucketcache.backends.JSONBackend(value, expiration_date=None, config=None)[source]¶

Bases: bucketcache.backends.Backend

Backend that stores objects using JSON.

default_config¶

alias of JSONConfig

class bucketcache.backends.MessagePackBackend(*args, **kwargs)[source]¶

Bases: bucketcache.backends.Backend

Backend that stores objects using MessagePack.

default_config¶

alias of MessagePackConfig