class Serializer(with_metaclass(ABCMeta, object)):
"""
The abstract base class for Serializers.
Allows TinyDB to handle arbitrary objects by running them through a list
of registerd serializers.
Every serializer has to tell which class it can handle.
"""
@abstractproperty
def OBJ_CLASS(self):
raise NotImplementedError('To be overriden!')
@abstractmethod
def encode(self, obj):
"""
Encode an object.
:param obj:
:return:
:rtype: str
"""
raise NotImplementedError('To be overriden!')
@abstractmethod
def decode(self, s):
"""
Decode an object.
:param s:
:type s: str
:return:
"""
raise NotImplementedError('To be overriden!')
class Storage(with_metaclass(ABCMeta, object)):
"""
The abstract base class for all Storages.
A Storage (de)serializes the current state of the database and stores it in
some place (memory, file on disk, ...).
"""
# Using ABCMeta as metaclass allows instantiating only storages that have
# implemented read and write
@abstractmethod
def read(self):
"""
Read the last stored state.
Any kind of deserialization should go here.
Raise ``ValueError`` here to indicate that the storage is empty.
:rtype: dict
"""
raise NotImplementedError('To be overriden!')
@abstractmethod
def write(self, data):
"""
Write the current state of the database to the storage.
Any kind of serialization should go here.
:param data: The current state of the database.
:type data: dict
"""
raise NotImplementedError('To be overriden!')
def close(self):
"""
Optional: Close open file handles, etc.
"""
pass