jsons._common_impl.set_deserializer() - Code Metrics - Inspection of "changed md to rst." - ramonhagenaars/jsons - Measure and Improve Code Quality continuously with Scrutinizer

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Branch — master (272386)

by Ramon

created 2018-08-20 06:00 UTC

jsons._common_impl.set_deserializer() A

↳ Parent: jsons._common_impl

Complexity

Conditions

Size

Total Lines	27
Code Lines	7

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	3
eloc	7
nop	4
dl	0
loc	27
rs	10
c	0
b	0
f	0

"""
This module contains common implementation details of jsons. This module is
private, do not import (from) it directly.
"""
import json
import re

VALID_TYPES = (str, int, float, bool, list, tuple, set, dict, type(None))
RFC3339_DATETIME_PATTERN = '%Y-%m-%dT%H:%M:%S'


def dump(obj: object, cls: type = None, fork_inst: type = None,
         **kwargs) -> object:
    """
    Serialize the given ``obj`` to a JSON equivalent type (e.g. dict, list,
    int, ...).

    The way objects are serialized can be finetuned by setting serializer
    functions for the specific type using ``set_serializer``.

    You can also provide ``cls`` to specify that ``obj`` needs to be serialized
    as if it was of type ``cls`` (meaning to only take into account attributes
    from ``cls``). The type ``cls`` must have a ``__slots__`` defined. Any type
    will do, but in most cases you may want ``cls`` to be a base class of
    ``obj``.
    :param obj: a Python instance of any sort.
    :param cls: if given, ``obj`` will be dumped as if it is of type ``type``.
    :param fork_inst: if given, it uses this fork of ``JsonSerializable``.
    :param kwargs: the keyword args are passed on to the serializer function.
    :return: the serialized obj as a JSON type.
    """
    if cls and not hasattr(cls, '__slots__'):
        raise KeyError('Invalid type: "{}", only types that have a __slots__ '
                       'defined are allowed.'.format(cls.__name__))
    cls_ = cls or obj.__class__
    cls_name = cls_.__name__.lower()
    fork_inst = fork_inst or JsonSerializable
    serializer = fork_inst._serializers.get(cls_name, None)
    if not serializer:
        parents = [cls_ser for cls_ser in fork_inst._classes_serializers
                   if isinstance(obj, cls_ser)]
        if parents:
            pname = parents[0].__name__.lower()
            serializer = fork_inst._serializers[pname]
    kwargs_ = {'fork_inst': fork_inst, **kwargs}
    return serializer(obj, cls=cls, **kwargs_)


def load(json_obj: dict, cls: type = None, strict: bool = False,
         fork_inst: type = None, **kwargs) -> object:
    """
    Deserialize the given ``json_obj`` to an object of type ``cls``. If the
    contents of ``json_obj`` do not match the interface of ``cls``, a
    TypeError is raised.

    If ``json_obj`` contains a value that belongs to a custom class, there must
    be a type hint present for that value in ``cls`` to let this function know
    what type it should deserialize that value to.


    **Example**:

    >>> from typing import List
    >>> import jsons
    >>> class Person:
    ...     # No type hint required for name
    ...     def __init__(self, name):
    ...         self.name = name
    >>> class Family:
    ...     # Person is a custom class, use a type hint
    ...         def __init__(self, persons: List[Person]):
    ...             self.persons = persons
    >>> loaded = jsons.load({'persons': [{'name': 'John'}]}, Family)
    >>> loaded.persons[0].name
    'John'

    If no ``cls`` is given, a dict is simply returned, but contained values
    (e.g. serialized ``datetime`` values) are still deserialized.

    If `strict` mode is off and the type of `json_obj` exactly matches `cls`
    then `json_obj` is simply returned.

    :param json_obj: the dict that is to be deserialized.
    :param cls: a matching class of which an instance should be returned.
    :param strict: a bool to determine if a partially deserialized `json_obj`
    is tolerated.
    :param fork_inst: if given, it uses this fork of ``JsonSerializable``.
    :param kwargs: the keyword args are passed on to the deserializer function.
    :return: an instance of ``cls`` if given, a dict otherwise.
    """
    if not strict and type(json_obj) == cls:

        return json_obj
    if type(json_obj) not in VALID_TYPES:

        raise KeyError('Invalid type: "{}", only arguments of the following '
                       'types are allowed: {}'
                       .format(type(json_obj).__name__,
                               ", ".join(typ.__name__ for typ
                                         in VALID_TYPES)))
    cls = cls or type(json_obj)
    deserializer = _get_deserializer(cls, fork_inst)
    kwargs_ = {'strict': strict, 'fork_inst': fork_inst, **kwargs}
    return deserializer(json_obj, cls, **kwargs_)


def _get_deserializer(cls: type, fork_inst: type = None):
    fork_inst = fork_inst or JsonSerializable
    cls_name = cls.__name__ if hasattr(cls, '__name__') \
        else cls.__origin__.__name__
    deserializer = fork_inst._deserializers.get(cls_name.lower(), None)
    if not deserializer:
        parents = [cls_ for cls_ in fork_inst._classes_deserializers
                   if issubclass(cls, cls_)]
        if parents:
            pname = parents[0].__name__.lower()
            deserializer = fork_inst._deserializers[pname]
    return deserializer


class JsonSerializable:

    """
    This class offers an alternative to using the ``jsons.load`` and
    ``jsons.dump`` methods. An instance of a class that inherits from
    ``JsonSerializable`` has the ``json`` property, which value is equivalent
    to calling ``jsons.dump`` on that instance. Furthermore, you can call
    ``from_json`` on that class, which is equivalent to calling ``json.load``
    with that class as an argument.
    """
    _classes_serializers = list()
    _classes_deserializers = list()
    _serializers = dict()
    _deserializers = dict()
    _fork_counter = 0

    @classmethod
    def fork(cls, name: str = None) -> type:
        """
        Create a 'fork' of ``JsonSerializable``: a new ``type`` with a separate
        configuration of serializers and deserializers.
        :param name: the ``__name__`` of the new ``type``.
        :return: a new ``type`` based on ``JsonSerializable``.
        """
        cls._fork_counter += 1
        class_name = name or '{}_fork{}'.format(cls.__name__,
                                                cls._fork_counter)
        result = type(class_name, (cls,), {})
        result._classes_serializers = cls._classes_serializers.copy()
        result._classes_deserializers = cls._classes_deserializers.copy()
        result._serializers = cls._serializers.copy()
        result._deserializers = cls._deserializers.copy()
        result._fork_counter = 0
        return result

    @classmethod
    def with_dump(cls, fork: bool = False, **kwargs) -> type:
        """
        Return a class (``type``) that is based on JsonSerializable with the
        ``dump`` method being automatically provided the given ``kwargs``.

        **Example:**

        >>> custom_serializable = JsonSerializable\
                .with_dump(key_transformer=KEY_TRANSFORMER_CAMELCASE)
        >>> class Person(custom_serializable):
        ...     def __init__(self, my_name):
        ...         self.my_name = my_name
        >>> p = Person('John')
        >>> p.json
        {'myName': 'John'}

        :param kwargs: the keyword args that are automatically provided to the
        ``dump`` method.
        :param fork: determines that a new fork is to be created.
        :return: a class with customized behavior.
        """
        def _wrapper(inst, **kwargs_):
            return dump(inst, **{**kwargs_, **kwargs})

        type_ = cls.fork() if fork else cls
        type_.dump = _wrapper
        return type_

    @classmethod
    def with_load(cls, fork: bool = False, **kwargs) -> type:
        """
        Return a class (``type``) that is based on JsonSerializable with the
        ``load`` method being automatically provided the given ``kwargs``.

        **Example:**

        >>> custom_serializable = JsonSerializable\
                .with_load(key_transformer=KEY_TRANSFORMER_SNAKECASE)
        >>> class Person(custom_serializable):
        ...     def __init__(self, my_name):
        ...         self.my_name = my_name
        >>> p_json = {'myName': 'John'}
        >>> p = Person.from_json(p_json)
        >>> p.my_name
        'John'

        :param kwargs: the keyword args that are automatically provided to the
        ``load`` method.
        :param fork: determines that a new fork is to be created.
        :return: a class with customized behavior.
        """
        @classmethod
        def _wrapper(cls_, inst, **kwargs_):
            return load(inst, cls_, **{**kwargs_, **kwargs})
        type_ = cls.fork() if fork else cls
        type_.load = _wrapper
        return type_

    @property
    def json(self) -> dict:
        """
        See ``jsons.dump``.
        :return: this instance in a JSON representation (dict).
        """
        return self.dump()

    @classmethod
    def from_json(cls: type, json_obj: dict, **kwargs) -> object:
        """
        See ``jsons.load``.
        :param json_obj: a JSON representation of an instance of the inheriting
        class
        :param kwargs: the keyword args are passed on to the deserializer
        function.
        :return: an instance of the inheriting class.
        """
        return cls.load(json_obj, **kwargs)

    def dump(self, **kwargs) -> dict:
        """
        See ``jsons.dump``.
        :param kwargs: the keyword args are passed on to the serializer
        function.
        :return: this instance in a JSON representation (dict).
        """
        return dump(self, fork_inst=self.__class__, **kwargs)

    @classmethod
    def load(cls: type, json_obj: dict, **kwargs) -> object:
        """
        See ``jsons.load``.
        :param kwargs: the keyword args are passed on to the serializer
        function.
        :return: this instance in a JSON representation (dict).
        """
        return load(json_obj, cls, fork_inst=cls, **kwargs)

    @classmethod
    def set_serializer(cls: type, func: callable, cls_: type,
                       high_prio: bool = True, fork: bool = False) -> type:
        """
        See ``jsons.set_serializer``.
        :param func: the serializer function.
        :param cls_: the type this serializer can handle.
        :param high_prio: determines the order in which is looked for the
        callable.
        :param fork: determines that a new fork is to be created.
        :return: the type on which this method is invoked or its fork.
        """
        type_ = cls.fork() if fork else cls
        set_serializer(func, cls_, high_prio, type_)
        return type_

    @classmethod
    def set_deserializer(cls: type, func: callable, cls_: type,
                         high_prio: bool = True, fork: bool = False) -> type:
        """
        See ``jsons.set_deserializer``.
        :param func: the deserializer function.
        :param cls_: the type this serializer can handle.
        :param high_prio: determines the order in which is looked for the
        callable.
        :param fork: determines that a new fork is to be created.
        :return: the type on which this method is invoked or its fork.
        """
        type_ = cls.fork() if fork else cls
        set_deserializer(func, cls_, high_prio, type_)
        return type_


def dumps(obj: object, *args, **kwargs) -> str:
    """
    Extend ``json.dumps``, allowing any Python instance to be dumped to a
    string. Any extra (keyword) arguments are passed on to ``json.dumps``.

    :param obj: the object that is to be dumped to a string.
    :param args: extra arguments for ``json.dumps``.
    :param kwargs: extra keyword arguments for ``json.dumps``. They are also
    passed on to the serializer function.
    :return: ``obj`` as a ``str``.
    """
    return json.dumps(dump(obj, **kwargs), *args, **kwargs)


def loads(str_: str, cls: type = None, *args, **kwargs) -> object:
    """
    Extend ``json.loads``, allowing a string to be loaded into a dict or a
    Python instance of type ``cls``. Any extra (keyword) arguments are passed
    on to ``json.loads``.

    :param str_: the string that is to be loaded.
    :param cls: a matching class of which an instance should be returned.
    :param args: extra arguments for ``json.dumps``.
    :param kwargs: extra keyword arguments for ``json.dumps``. They are also
    passed on to the deserializer function.
    :return: an instance of type ``cls`` or a dict if no ``cls`` is given.
    """
    obj = json.loads(str_, *args, **kwargs)
    return load(obj, cls, **kwargs) if cls else obj


def set_serializer(func: callable, cls: type, high_prio: bool = True,
                   fork_inst: type = JsonSerializable) -> None:
    """
    Set a serializer function for the given type. You may override the default
    behavior of ``jsons.load`` by setting a custom serializer.

    The ``func`` argument must take one argument (i.e. the object that is to be
    serialized) and also a ``kwargs`` parameter. For example:

    >>> def func(obj, **kwargs):
    ...    return dict()

    You may ask additional arguments between ``cls`` and ``kwargs``.

    :param func: the serializer function.
    :param cls: the type this serializer can handle.
    :param high_prio: determines the order in which is looked for the callable.
    :param fork_inst: if given, it uses this fork of ``JsonSerializable``.
    :return: None.
    """
    if cls:
        index = 0 if high_prio else len(fork_inst._classes_serializers)
        fork_inst._classes_serializers.insert(index, cls)
        fork_inst._serializers[cls.__name__.lower()] = func
    else:
        fork_inst._serializers['nonetype'] = func


def set_deserializer(func: callable, cls: type, high_prio: bool = True,
                     fork_inst: type = JsonSerializable) -> None:
    """
    Set a deserializer function for the given type. You may override the
    default behavior of ``jsons.dump`` by setting a custom deserializer.

    The ``func`` argument must take two arguments (i.e. the dict containing the
    serialized values and the type that the values should be deserialized into)
    and also a ``kwargs`` parameter. For example:

    >>> def func(dict_, cls, **kwargs):
    ...    return cls()

    You may ask additional arguments between ``cls`` and ``kwargs``.

    :param func: the deserializer function.
    :param cls: the type this serializer can handle.
    :param high_prio: determines the order in which is looked for the callable.
    :param fork_inst: if given, it uses this fork of ``JsonSerializable``.
    :return: None.
    """
    if cls:
        index = 0 if high_prio else len(fork_inst._classes_deserializers)
        fork_inst._classes_deserializers.insert(index, cls)
        fork_inst._deserializers[cls.__name__.lower()] = func
    else:
        fork_inst._deserializers['nonetype'] = func


def camelcase(str_: str) -> str:
    """
    Return ``s`` in camelCase.
    :param str_: the string that is to be transformed.
    :return: a string in camelCase.
    """
    str_ = str_.replace('-', '_')
    splitted = str_.split('_')
    if len(splitted) > 1:
        str_ = ''.join([x.title() for x in splitted])
    return str_[0].lower() + str_[1:]


def snakecase(str_: str) -> str:
    """
    Return ``s`` in snake_case.
    :param str_: the string that is to be transformed.
    :return: a string in snake_case.
    """
    str_ = str_.replace('-', '_')
    str_ = str_[0].lower() + str_[1:]
    return re.sub(r'([a-z])([A-Z])', '\\1_\\2', str_).lower()


def pascalcase(str_: str) -> str:
    """
    Return ``s`` in PascalCase.
    :param str_: the string that is to be transformed.
    :return: a string in PascalCase.
    """
    camelcase_str = camelcase(str_)
    return camelcase_str[0].upper() + camelcase_str[1:]


def lispcase(str_: str) -> str:
    """
    Return ``s`` in lisp-case.
    :param str_: the string that is to be transformed.
    :return: a string in lisp-case.
    """
    return snakecase(str_).replace('_', '-')


1			"""
2			This module contains common implementation details of jsons. This module is
3			private, do not import (from) it directly.
4			"""
5			import json
6			import re
7
8			VALID_TYPES = (str, int, float, bool, list, tuple, set, dict, type(None))
9			RFC3339_DATETIME_PATTERN = '%Y-%m-%dT%H:%M:%S'
10
11
12			def dump(obj: object, cls: type = None, fork_inst: type = None,
13			**kwargs) -> object:
14			"""
15			Serialize the given ``obj`` to a JSON equivalent type (e.g. dict, list,
16			int, ...).
17
18			The way objects are serialized can be finetuned by setting serializer
19			functions for the specific type using ``set_serializer``.
20
21			You can also provide ``cls`` to specify that ``obj`` needs to be serialized
22			as if it was of type ``cls`` (meaning to only take into account attributes
23			from ``cls``). The type ``cls`` must have a ``__slots__`` defined. Any type
24			will do, but in most cases you may want ``cls`` to be a base class of
25			``obj``.
26			:param obj: a Python instance of any sort.
27			:param cls: if given, ``obj`` will be dumped as if it is of type ``type``.
28			:param fork_inst: if given, it uses this fork of ``JsonSerializable``.
29			:param kwargs: the keyword args are passed on to the serializer function.
30			:return: the serialized obj as a JSON type.
31			"""
32			if cls and not hasattr(cls, '__slots__'):
33			raise KeyError('Invalid type: "{}", only types that have a __slots__ '
34			'defined are allowed.'.format(cls.__name__))
35			cls_ = cls or obj.__class__
36			cls_name = cls_.__name__.lower()
37			fork_inst = fork_inst or JsonSerializable
38			serializer = fork_inst._serializers.get(cls_name, None)
39			if not serializer:
40			parents = [cls_ser for cls_ser in fork_inst._classes_serializers
41			if isinstance(obj, cls_ser)]
42			if parents:
43			pname = parents[0].__name__.lower()
44			serializer = fork_inst._serializers[pname]
45			kwargs_ = {'fork_inst': fork_inst, **kwargs}
46			return serializer(obj, cls=cls, **kwargs_)
47
48
49			def load(json_obj: dict, cls: type = None, strict: bool = False,
50			fork_inst: type = None, **kwargs) -> object:
51			"""
52			Deserialize the given ``json_obj`` to an object of type ``cls``. If the
53			contents of ``json_obj`` do not match the interface of ``cls``, a
54			TypeError is raised.
55
56			If ``json_obj`` contains a value that belongs to a custom class, there must
57			be a type hint present for that value in ``cls`` to let this function know
58			what type it should deserialize that value to.
59
60
61			Example:
62
63			>>> from typing import List
64			>>> import jsons
65			>>> class Person:
66			... # No type hint required for name
67			... def __init__(self, name):
68			... self.name = name
69			>>> class Family:
70			... # Person is a custom class, use a type hint
71			... def __init__(self, persons: List[Person]):
72			... self.persons = persons
73			>>> loaded = jsons.load({'persons': [{'name': 'John'}]}, Family)
74			>>> loaded.persons[0].name
75			'John'
76
77			If no ``cls`` is given, a dict is simply returned, but contained values
78			(e.g. serialized ``datetime`` values) are still deserialized.
79
80			If `strict` mode is off and the type of `json_obj` exactly matches `cls`
81			then `json_obj` is simply returned.
82
83			:param json_obj: the dict that is to be deserialized.
84			:param cls: a matching class of which an instance should be returned.
85			:param strict: a bool to determine if a partially deserialized `json_obj`
86			is tolerated.
87			:param fork_inst: if given, it uses this fork of ``JsonSerializable``.
88			:param kwargs: the keyword args are passed on to the deserializer function.
89			:return: an instance of ``cls`` if given, a dict otherwise.
90			"""
91			if not strict and type(json_obj) == cls:
			0 ignored issues – show introduced 2018-08-19 20:11 UTC by Report Bug Copy Issue Report Using type() instead of isinstance() for a typecheck. Loading history...
92			return json_obj
93			if type(json_obj) not in VALID_TYPES:
			0 ignored issues – show introduced 2018-08-19 20:11 UTC by Report Bug Copy Issue Report Using type() instead of isinstance() for a typecheck. Loading history...
94			raise KeyError('Invalid type: "{}", only arguments of the following '
95			'types are allowed: {}'
96			.format(type(json_obj).__name__,
97			", ".join(typ.__name__ for typ
98			in VALID_TYPES)))
99			cls = cls or type(json_obj)
100			deserializer = _get_deserializer(cls, fork_inst)
101			kwargs_ = {'strict': strict, 'fork_inst': fork_inst, **kwargs}
102			return deserializer(json_obj, cls, **kwargs_)
103
104
105			def _get_deserializer(cls: type, fork_inst: type = None):
106			fork_inst = fork_inst or JsonSerializable
107			cls_name = cls.__name__ if hasattr(cls, '__name__') \
108			else cls.__origin__.__name__
109			deserializer = fork_inst._deserializers.get(cls_name.lower(), None)
110			if not deserializer:
111			parents = [cls_ for cls_ in fork_inst._classes_deserializers
112			if issubclass(cls, cls_)]
113			if parents:
114			pname = parents[0].__name__.lower()
115			deserializer = fork_inst._deserializers[pname]
116			return deserializer
117
118
119			class JsonSerializable:
			0 ignored issues – show Unused Code introduced 2018-08-19 20:11 UTC by Report Bug Copy Issue Report The variable `__class__` seems to be unused. Loading history...
120			"""
121			This class offers an alternative to using the ``jsons.load`` and
122			``jsons.dump`` methods. An instance of a class that inherits from
123			``JsonSerializable`` has the ``json`` property, which value is equivalent
124			to calling ``jsons.dump`` on that instance. Furthermore, you can call
125			``from_json`` on that class, which is equivalent to calling ``json.load``
126			with that class as an argument.
127			"""
128			_classes_serializers = list()
129			_classes_deserializers = list()
130			_serializers = dict()
131			_deserializers = dict()
132			_fork_counter = 0
133
134			@classmethod
135			def fork(cls, name: str = None) -> type:
136			"""
137			Create a 'fork' of ``JsonSerializable``: a new ``type`` with a separate
138			configuration of serializers and deserializers.
139			:param name: the ``__name__`` of the new ``type``.
140			:return: a new ``type`` based on ``JsonSerializable``.
141			"""
142			cls._fork_counter += 1
143			class_name = name or '{}_fork{}'.format(cls.__name__,
144			cls._fork_counter)
145			result = type(class_name, (cls,), {})
146			result._classes_serializers = cls._classes_serializers.copy()
147			result._classes_deserializers = cls._classes_deserializers.copy()
148			result._serializers = cls._serializers.copy()
149			result._deserializers = cls._deserializers.copy()
150			result._fork_counter = 0
151			return result
152
153			@classmethod
154			def with_dump(cls, fork: bool = False, **kwargs) -> type:
155			"""
156			Return a class (``type``) that is based on JsonSerializable with the
157			``dump`` method being automatically provided the given ``kwargs``.
158
159			Example:
160
161			>>> custom_serializable = JsonSerializable\
162			.with_dump(key_transformer=KEY_TRANSFORMER_CAMELCASE)
163			>>> class Person(custom_serializable):
164			... def __init__(self, my_name):
165			... self.my_name = my_name
166			>>> p = Person('John')
167			>>> p.json
168			{'myName': 'John'}
169
170			:param kwargs: the keyword args that are automatically provided to the
171			``dump`` method.
172			:param fork: determines that a new fork is to be created.
173			:return: a class with customized behavior.
174			"""
175			def _wrapper(inst, **kwargs_):
176			return dump(inst, {kwargs_, **kwargs})
177
178			type_ = cls.fork() if fork else cls
179			type_.dump = _wrapper
180			return type_
181
182			@classmethod
183			def with_load(cls, fork: bool = False, **kwargs) -> type:
184			"""
185			Return a class (``type``) that is based on JsonSerializable with the
186			``load`` method being automatically provided the given ``kwargs``.
187
188			Example:
189
190			>>> custom_serializable = JsonSerializable\
191			.with_load(key_transformer=KEY_TRANSFORMER_SNAKECASE)
192			>>> class Person(custom_serializable):
193			... def __init__(self, my_name):
194			... self.my_name = my_name
195			>>> p_json = {'myName': 'John'}
196			>>> p = Person.from_json(p_json)
197			>>> p.my_name
198			'John'
199
200			:param kwargs: the keyword args that are automatically provided to the
201			``load`` method.
202			:param fork: determines that a new fork is to be created.
203			:return: a class with customized behavior.
204			"""
205			@classmethod
206			def _wrapper(cls_, inst, **kwargs_):
207			return load(inst, cls_, {kwargs_, **kwargs})
208			type_ = cls.fork() if fork else cls
209			type_.load = _wrapper
210			return type_
211
212			@property
213			def json(self) -> dict:
214			"""
215			See ``jsons.dump``.
216			:return: this instance in a JSON representation (dict).
217			"""
218			return self.dump()
219
220			@classmethod
221			def from_json(cls: type, json_obj: dict, **kwargs) -> object:
222			"""
223			See ``jsons.load``.
224			:param json_obj: a JSON representation of an instance of the inheriting
225			class
226			:param kwargs: the keyword args are passed on to the deserializer
227			function.
228			:return: an instance of the inheriting class.
229			"""
230			return cls.load(json_obj, **kwargs)
231
232			def dump(self, **kwargs) -> dict:
233			"""
234			See ``jsons.dump``.
235			:param kwargs: the keyword args are passed on to the serializer
236			function.
237			:return: this instance in a JSON representation (dict).
238			"""
239			return dump(self, fork_inst=self.__class__, **kwargs)
240
241			@classmethod
242			def load(cls: type, json_obj: dict, **kwargs) -> object:
243			"""
244			See ``jsons.load``.
245			:param kwargs: the keyword args are passed on to the serializer
246			function.
247			:return: this instance in a JSON representation (dict).
248			"""
249			return load(json_obj, cls, fork_inst=cls, **kwargs)
250
251			@classmethod
252			def set_serializer(cls: type, func: callable, cls_: type,
253			high_prio: bool = True, fork: bool = False) -> type:
254			"""
255			See ``jsons.set_serializer``.
256			:param func: the serializer function.
257			:param cls_: the type this serializer can handle.
258			:param high_prio: determines the order in which is looked for the
259			callable.
260			:param fork: determines that a new fork is to be created.
261			:return: the type on which this method is invoked or its fork.
262			"""
263			type_ = cls.fork() if fork else cls
264			set_serializer(func, cls_, high_prio, type_)
265			return type_
266
267			@classmethod
268			def set_deserializer(cls: type, func: callable, cls_: type,
269			high_prio: bool = True, fork: bool = False) -> type:
270			"""
271			See ``jsons.set_deserializer``.
272			:param func: the deserializer function.
273			:param cls_: the type this serializer can handle.
274			:param high_prio: determines the order in which is looked for the
275			callable.
276			:param fork: determines that a new fork is to be created.
277			:return: the type on which this method is invoked or its fork.
278			"""
279			type_ = cls.fork() if fork else cls
280			set_deserializer(func, cls_, high_prio, type_)
281			return type_
282
283
284			def dumps(obj: object, args, *kwargs) -> str:
285			"""
286			Extend ``json.dumps``, allowing any Python instance to be dumped to a
287			string. Any extra (keyword) arguments are passed on to ``json.dumps``.
288
289			:param obj: the object that is to be dumped to a string.
290			:param args: extra arguments for ``json.dumps``.
291			:param kwargs: extra keyword arguments for ``json.dumps``. They are also
292			passed on to the serializer function.
293			:return: ``obj`` as a ``str``.
294			"""
295			return json.dumps(dump(obj, *kwargs), args, **kwargs)
296
297
298			def loads(str_: str, cls: type = None, args, *kwargs) -> object:
299			"""
300			Extend ``json.loads``, allowing a string to be loaded into a dict or a
301			Python instance of type ``cls``. Any extra (keyword) arguments are passed
302			on to ``json.loads``.
303
304			:param str_: the string that is to be loaded.
305			:param cls: a matching class of which an instance should be returned.
306			:param args: extra arguments for ``json.dumps``.
307			:param kwargs: extra keyword arguments for ``json.dumps``. They are also
308			passed on to the deserializer function.
309			:return: an instance of type ``cls`` or a dict if no ``cls`` is given.
310			"""
311			obj = json.loads(str_, args, *kwargs)
312			return load(obj, cls, **kwargs) if cls else obj
313
314
315			def set_serializer(func: callable, cls: type, high_prio: bool = True,
316			fork_inst: type = JsonSerializable) -> None:
317			"""
318			Set a serializer function for the given type. You may override the default
319			behavior of ``jsons.load`` by setting a custom serializer.
320
321			The ``func`` argument must take one argument (i.e. the object that is to be
322			serialized) and also a ``kwargs`` parameter. For example:
323
324			>>> def func(obj, **kwargs):
325			... return dict()
326
327			You may ask additional arguments between ``cls`` and ``kwargs``.
328
329			:param func: the serializer function.
330			:param cls: the type this serializer can handle.
331			:param high_prio: determines the order in which is looked for the callable.
332			:param fork_inst: if given, it uses this fork of ``JsonSerializable``.
333			:return: None.
334			"""
335			if cls:
336			index = 0 if high_prio else len(fork_inst._classes_serializers)
337			fork_inst._classes_serializers.insert(index, cls)
338			fork_inst._serializers[cls.__name__.lower()] = func
339			else:
340			fork_inst._serializers['nonetype'] = func
341
342
343			def set_deserializer(func: callable, cls: type, high_prio: bool = True,
344			fork_inst: type = JsonSerializable) -> None:
345			"""
346			Set a deserializer function for the given type. You may override the
347			default behavior of ``jsons.dump`` by setting a custom deserializer.
348
349			The ``func`` argument must take two arguments (i.e. the dict containing the
350			serialized values and the type that the values should be deserialized into)
351			and also a ``kwargs`` parameter. For example:
352
353			>>> def func(dict_, cls, **kwargs):
354			... return cls()
355
356			You may ask additional arguments between ``cls`` and ``kwargs``.
357
358			:param func: the deserializer function.
359			:param cls: the type this serializer can handle.
360			:param high_prio: determines the order in which is looked for the callable.
361			:param fork_inst: if given, it uses this fork of ``JsonSerializable``.
362			:return: None.
363			"""
364			if cls:
365			index = 0 if high_prio else len(fork_inst._classes_deserializers)
366			fork_inst._classes_deserializers.insert(index, cls)
367			fork_inst._deserializers[cls.__name__.lower()] = func
368			else:
369			fork_inst._deserializers['nonetype'] = func
370
371
372			def camelcase(str_: str) -> str:
373			"""
374			Return ``s`` in camelCase.
375			:param str_: the string that is to be transformed.
376			:return: a string in camelCase.
377			"""
378			str_ = str_.replace('-', '_')
379			splitted = str_.split('_')
380			if len(splitted) > 1:
381			str_ = ''.join([x.title() for x in splitted])
382			return str_[0].lower() + str_[1:]
383
384
385			def snakecase(str_: str) -> str:
386			"""
387			Return ``s`` in snake_case.
388			:param str_: the string that is to be transformed.
389			:return: a string in snake_case.
390			"""
391			str_ = str_.replace('-', '_')
392			str_ = str_[0].lower() + str_[1:]
393			return re.sub(r'([a-z])([A-Z])', '\\1_\\2', str_).lower()
394
395
396			def pascalcase(str_: str) -> str:
397			"""
398			Return ``s`` in PascalCase.
399			:param str_: the string that is to be transformed.
400			:return: a string in PascalCase.
401			"""
402			camelcase_str = camelcase(str_)
403			return camelcase_str[0].upper() + camelcase_str[1:]
404
405
406			def lispcase(str_: str) -> str:
407			"""
408			Return ``s`` in lisp-case.
409			:param str_: the string that is to be transformed.
410			:return: a string in lisp-case.
411			"""
412			return snakecase(str_).replace('_', '-')
413

ramonhagenaars / jsons

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jsons._common_impl.set_deserializer() A

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