jsons._load_impl.load() - Code Metrics - Inspection of "Release/0.8.7" - ramonhagenaars/jsons - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Pull Request — master (#49)

by Ramon

created 2019-04-22 15:29 UTC

jsons._load_impl.load() B

↳ Parent: jsons._load_impl

Complexity

Conditions

Size

Total Lines	70
Code Lines	26

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
eloc	26
dl	0
loc	70
rs	8.7893
c	0
b	0
f	0
cc	5
nop	6

How to fix Long Method

"""
PRIVATE MODULE: do not import (from) it directly.

This module contains functionality for loading stuff from json.
"""
import json
from json import JSONDecodeError
from typing import Optional, Dict, Callable, Tuple
from jsons._lizers_impl import get_deserializer
from jsons.exceptions import DeserializationError, JsonsError, DecodeError
from jsons._common_impl import (
    StateHolder,
    get_cls_from_str,
    get_class_name,
    get_cls_and_meta,
    determine_precedence,
    VALID_TYPES)


def load(
        json_obj: object,
        cls: Optional[type] = None,
        strict: bool = False,
        fork_inst: Optional[type] = StateHolder,
        attr_getters: Optional[Dict[str, Callable[[], object]]] = 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
    DeserializationError 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 the deserializer should be strict
    (i.e. fail on a partially deserialized `json_obj` or on `None`).
    :param fork_inst: if given, it uses this fork of ``JsonSerializable``.
    :param attr_getters: a ``dict`` that may hold callables that return values
    for certain attributes.
    :param kwargs: the keyword args are passed on to the deserializer function.
    :return: an instance of ``cls`` if given, a dict otherwise.
    """
    if _should_skip(json_obj, cls, strict):
        return json_obj
    if isinstance(cls, str):
        cls = get_cls_from_str(cls, json_obj, fork_inst)
    cls, meta_hints = _check_and_get_cls_and_meta_hints(
        json_obj, cls, fork_inst, kwargs.get('_inferred_cls', False))

    deserializer = get_deserializer(cls, fork_inst)
    kwargs_ = {
        'strict': strict,
        'fork_inst': fork_inst,
        'attr_getters': attr_getters,
        'meta_hints': meta_hints,
        **kwargs
    }
    try:
        return deserializer(json_obj, cls, **kwargs_)
    except Exception as err:
        if isinstance(err, JsonsError):
            raise
        raise DeserializationError(str(err), json_obj, cls)


def loads(
        str_: str,
        cls: Optional[type] = None,
        jdkwargs: Optional[Dict[str, object]] = 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 jdkwargs: extra keyword arguments for ``json.loads`` (not
    ``jsons.loads``!)
    :param args: extra arguments for ``jsons.loads``.
    :param kwargs: extra keyword arguments for ``jsons.loads``.
    :return: a JSON-type object (dict, str, list, etc.) or an instance of type
    ``cls`` if given.
    """
    jdkwargs = jdkwargs or {}
    try:
        obj = json.loads(str_, **jdkwargs)
    except JSONDecodeError as err:
        raise DecodeError('Could not load a dict; the given string is not '
                          'valid JSON.', str_, cls, err)
    else:
        return load(obj, cls, *args, **kwargs)


def loadb(
        bytes_: bytes,
        cls: Optional[type] = None,
        encoding: str = 'utf-8',
        jdkwargs: Optional[Dict[str, object]] = None,
        *args,
        **kwargs) -> object:
    """
    Extend ``json.loads``, allowing bytes to be loaded into a dict or a Python
    instance of type ``cls``. Any extra (keyword) arguments are passed on to
    ``json.loads``.

    :param bytes_: the bytes that are to be loaded.
    :param cls: a matching class of which an instance should be returned.
    :param encoding: the encoding that is used to transform from bytes.
    :param jdkwargs: extra keyword arguments for ``json.loads`` (not
    ``jsons.loads``!)
    :param args: extra arguments for ``jsons.loads``.
    :param kwargs: extra keyword arguments for ``jsons.loads``.
    :return: a JSON-type object (dict, str, list, etc.) or an instance of type
    ``cls`` if given.
    """
    if not isinstance(bytes_, bytes):
        raise DeserializationError('loadb accepts bytes only, "{}" was given'
                                   .format(type(bytes_)), bytes_, cls)
    jdkwargs = jdkwargs or {}
    str_ = bytes_.decode(encoding=encoding)
    return loads(str_, cls, jdkwargs=jdkwargs, *args, **kwargs)


def _check_and_get_cls_and_meta_hints(
        json_obj: object,
        cls: type,
        fork_inst: type,
        inferred_cls: bool) -> Tuple[type, Optional[dict]]:
    # Check if json_obj is of a valid type and return the cls.
    if type(json_obj) not in VALID_TYPES:
        invalid_type = get_class_name(type(json_obj), fork_inst=fork_inst,
                                      fully_qualified=True)
        valid_types = [get_class_name(typ, fork_inst=fork_inst,
                                      fully_qualified=True)
                       for typ in VALID_TYPES]
        msg = ('Invalid type: "{}", only arguments of the following types are '
               'allowed: {}'.format(invalid_type, ", ".join(valid_types)))
        raise DeserializationError(msg, json_obj, cls)
    if json_obj is None:
        raise DeserializationError('Cannot load None with strict=True',
                                   json_obj, cls)

    cls_from_meta, meta = get_cls_and_meta(json_obj, fork_inst)
    meta_hints = meta.get('classes', {}) if meta else {}
    return determine_precedence(
        cls, cls_from_meta, type(json_obj), inferred_cls), meta_hints


def _should_skip(json_obj: object, cls: type, strict: bool):
    if not strict and (json_obj is None or type(json_obj) == cls):
        return True


1			"""
2			PRIVATE MODULE: do not import (from) it directly.
3
4			This module contains functionality for loading stuff from json.
5			"""
6			import json
7			from json import JSONDecodeError
8			from typing import Optional, Dict, Callable, Tuple
9			from jsons._lizers_impl import get_deserializer
10			from jsons.exceptions import DeserializationError, JsonsError, DecodeError
11			from jsons._common_impl import (
12			StateHolder,
13			get_cls_from_str,
14			get_class_name,
15			get_cls_and_meta,
16			determine_precedence,
17			VALID_TYPES)
18
19
20			def load(
21			json_obj: object,
22			cls: Optional[type] = None,
23			strict: bool = False,
24			fork_inst: Optional[type] = StateHolder,
25			attr_getters: Optional[Dict[str, Callable[[], object]]] = None,
26			**kwargs) -> object:
27			"""
28			Deserialize the given ``json_obj`` to an object of type ``cls``. If the
29			contents of ``json_obj`` do not match the interface of ``cls``, a
30			DeserializationError is raised.
31
32			If ``json_obj`` contains a value that belongs to a custom class, there must
33			be a type hint present for that value in ``cls`` to let this function know
34			what type it should deserialize that value to.
35
36
37			Example:
38
39			>>> from typing import List
40			>>> import jsons
41			>>> class Person:
42			... # No type hint required for name
43			... def __init__(self, name):
44			... self.name = name
45			>>> class Family:
46			... # Person is a custom class, use a type hint
47			... def __init__(self, persons: List[Person]):
48			... self.persons = persons
49			>>> loaded = jsons.load({'persons': [{'name': 'John'}]}, Family)
50			>>> loaded.persons[0].name
51			'John'
52
53			If no ``cls`` is given, a dict is simply returned, but contained values
54			(e.g. serialized ``datetime`` values) are still deserialized.
55
56			If `strict` mode is off and the type of `json_obj` exactly matches `cls`
57			then `json_obj` is simply returned.
58
59			:param json_obj: the dict that is to be deserialized.
60			:param cls: a matching class of which an instance should be returned.
61			:param strict: a bool to determine if the deserializer should be strict
62			(i.e. fail on a partially deserialized `json_obj` or on `None`).
63			:param fork_inst: if given, it uses this fork of ``JsonSerializable``.
64			:param attr_getters: a ``dict`` that may hold callables that return values
65			for certain attributes.
66			:param kwargs: the keyword args are passed on to the deserializer function.
67			:return: an instance of ``cls`` if given, a dict otherwise.
68			"""
69			if _should_skip(json_obj, cls, strict):
70			return json_obj
71			if isinstance(cls, str):
72			cls = get_cls_from_str(cls, json_obj, fork_inst)
73			cls, meta_hints = _check_and_get_cls_and_meta_hints(
74			json_obj, cls, fork_inst, kwargs.get('_inferred_cls', False))
75
76			deserializer = get_deserializer(cls, fork_inst)
77			kwargs_ = {
78			'strict': strict,
79			'fork_inst': fork_inst,
80			'attr_getters': attr_getters,
81			'meta_hints': meta_hints,
82			**kwargs
83			}
84			try:
85			return deserializer(json_obj, cls, **kwargs_)
86			except Exception as err:
87			if isinstance(err, JsonsError):
88			raise
89			raise DeserializationError(str(err), json_obj, cls)
90
91
92			def loads(
93			str_: str,
94			cls: Optional[type] = None,
95			jdkwargs: Optional[Dict[str, object]] = None,
96			*args,
97			**kwargs) -> object:
98			"""
99			Extend ``json.loads``, allowing a string to be loaded into a dict or a
100			Python instance of type ``cls``. Any extra (keyword) arguments are passed
101			on to ``json.loads``.
102
103			:param str_: the string that is to be loaded.
104			:param cls: a matching class of which an instance should be returned.
105			:param jdkwargs: extra keyword arguments for ``json.loads`` (not
106			``jsons.loads``!)
107			:param args: extra arguments for ``jsons.loads``.
108			:param kwargs: extra keyword arguments for ``jsons.loads``.
109			:return: a JSON-type object (dict, str, list, etc.) or an instance of type
110			``cls`` if given.
111			"""
112			jdkwargs = jdkwargs or {}
113			try:
114			obj = json.loads(str_, **jdkwargs)
115			except JSONDecodeError as err:
116			raise DecodeError('Could not load a dict; the given string is not '
117			'valid JSON.', str_, cls, err)
118			else:
119			return load(obj, cls, args, *kwargs)
120
121
122			def loadb(
123			bytes_: bytes,
124			cls: Optional[type] = None,
125			encoding: str = 'utf-8',
126			jdkwargs: Optional[Dict[str, object]] = None,
127			*args,
128			**kwargs) -> object:
129			"""
130			Extend ``json.loads``, allowing bytes to be loaded into a dict or a Python
131			instance of type ``cls``. Any extra (keyword) arguments are passed on to
132			``json.loads``.
133
134			:param bytes_: the bytes that are to be loaded.
135			:param cls: a matching class of which an instance should be returned.
136			:param encoding: the encoding that is used to transform from bytes.
137			:param jdkwargs: extra keyword arguments for ``json.loads`` (not
138			``jsons.loads``!)
139			:param args: extra arguments for ``jsons.loads``.
140			:param kwargs: extra keyword arguments for ``jsons.loads``.
141			:return: a JSON-type object (dict, str, list, etc.) or an instance of type
142			``cls`` if given.
143			"""
144			if not isinstance(bytes_, bytes):
145			raise DeserializationError('loadb accepts bytes only, "{}" was given'
146			.format(type(bytes_)), bytes_, cls)
147			jdkwargs = jdkwargs or {}
148			str_ = bytes_.decode(encoding=encoding)
149			return loads(str_, cls, jdkwargs=jdkwargs, args, *kwargs)
150
151
152			def _check_and_get_cls_and_meta_hints(
153			json_obj: object,
154			cls: type,
155			fork_inst: type,
156			inferred_cls: bool) -> Tuple[type, Optional[dict]]:
157			# Check if json_obj is of a valid type and return the cls.
158			if type(json_obj) not in VALID_TYPES:
159			invalid_type = get_class_name(type(json_obj), fork_inst=fork_inst,
160			fully_qualified=True)
161			valid_types = [get_class_name(typ, fork_inst=fork_inst,
162			fully_qualified=True)
163			for typ in VALID_TYPES]
164			msg = ('Invalid type: "{}", only arguments of the following types are '
165			'allowed: {}'.format(invalid_type, ", ".join(valid_types)))
166			raise DeserializationError(msg, json_obj, cls)
167			if json_obj is None:
168			raise DeserializationError('Cannot load None with strict=True',
169			json_obj, cls)
170
171			cls_from_meta, meta = get_cls_and_meta(json_obj, fork_inst)
172			meta_hints = meta.get('classes', {}) if meta else {}
173			return determine_precedence(
174			cls, cls_from_meta, type(json_obj), inferred_cls), meta_hints
175
176
177			def _should_skip(json_obj: object, cls: type, strict: bool):
178			if not strict and (json_obj is None or type(json_obj) == cls):
179			return True
180

ramonhagenaars / jsons

Pull Request — master (#49)

jsons._load_impl.load() B

Complexity

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Duplication

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