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r"""JSON (JavaScript Object Notation) <https://json.org> is a subset of | |
JavaScript syntax (ECMA-262 3rd edition) used as a lightweight data | |
interchange format. | |
:mod:`json` exposes an API familiar to users of the standard library | |
:mod:`marshal` and :mod:`pickle` modules. It is derived from a | |
version of the externally maintained simplejson library. | |
Encoding basic Python object hierarchies:: | |
>>> import json | |
>>> json.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}]) | |
'["foo", {"bar": ["baz", null, 1.0, 2]}]' | |
>>> print(json.dumps("\"foo\bar")) | |
"\"foo\bar" | |
>>> print(json.dumps('\u1234')) | |
"\u1234" | |
>>> print(json.dumps('\\')) | |
"\\" | |
>>> print(json.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True)) | |
{"a": 0, "b": 0, "c": 0} | |
>>> from io import StringIO | |
>>> io = StringIO() | |
>>> json.dump(['streaming API'], io) | |
>>> io.getvalue() | |
'["streaming API"]' | |
Compact encoding:: | |
>>> import json | |
>>> mydict = {'4': 5, '6': 7} | |
>>> json.dumps([1,2,3,mydict], separators=(',', ':')) | |
'[1,2,3,{"4":5,"6":7}]' | |
Pretty printing:: | |
>>> import json | |
>>> print(json.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4)) | |
{ | |
"4": 5, | |
"6": 7 | |
} | |
Decoding JSON:: | |
>>> import json | |
>>> obj = ['foo', {'bar': ['baz', None, 1.0, 2]}] | |
>>> json.loads('["foo", {"bar":["baz", null, 1.0, 2]}]') == obj | |
True | |
>>> json.loads('"\\"foo\\bar"') == '"foo\x08ar' | |
True | |
>>> from io import StringIO | |
>>> io = StringIO('["streaming API"]') | |
>>> json.load(io)[0] == 'streaming API' | |
True | |
Specializing JSON object decoding:: | |
>>> import json | |
>>> def as_complex(dct): | |
... if '__complex__' in dct: | |
... return complex(dct['real'], dct['imag']) | |
... return dct | |
... | |
>>> json.loads('{"__complex__": true, "real": 1, "imag": 2}', | |
... object_hook=as_complex) | |
(1+2j) | |
>>> from decimal import Decimal | |
>>> json.loads('1.1', parse_float=Decimal) == Decimal('1.1') | |
True | |
Specializing JSON object encoding:: | |
>>> import json | |
>>> def encode_complex(obj): | |
... if isinstance(obj, complex): | |
... return [obj.real, obj.imag] | |
... raise TypeError(f'Object of type {obj.__class__.__name__} ' | |
... f'is not JSON serializable') | |
... | |
>>> json.dumps(2 + 1j, default=encode_complex) | |
'[2.0, 1.0]' | |
>>> json.JSONEncoder(default=encode_complex).encode(2 + 1j) | |
'[2.0, 1.0]' | |
>>> ''.join(json.JSONEncoder(default=encode_complex).iterencode(2 + 1j)) | |
'[2.0, 1.0]' | |
Using json.tool from the shell to validate and pretty-print:: | |
$ echo '{"json":"obj"}' | python -m json.tool | |
{ | |
"json": "obj" | |
} | |
$ echo '{ 1.2:3.4}' | python -m json.tool | |
Expecting property name enclosed in double quotes: line 1 column 3 (char 2) | |
""" | |
__version__ = '2.0.9' | |
__all__ = [ | |
'dump', 'dumps', 'load', 'loads', | |
'JSONDecoder', 'JSONDecodeError', 'JSONEncoder', | |
] | |
__author__ = 'Bob Ippolito <[email protected]>' | |
from .decoder import JSONDecoder, JSONDecodeError | |
from .encoder import JSONEncoder | |
import codecs | |
_default_encoder = JSONEncoder( | |
skipkeys=False, | |
ensure_ascii=True, | |
check_circular=True, | |
allow_nan=True, | |
indent=None, | |
separators=None, | |
default=None, | |
) | |
def dump(obj, fp, *, skipkeys=False, ensure_ascii=True, check_circular=True, | |
allow_nan=True, cls=None, indent=None, separators=None, | |
default=None, sort_keys=False, **kw): | |
"""Serialize ``obj`` as a JSON formatted stream to ``fp`` (a | |
``.write()``-supporting file-like object). | |
If ``skipkeys`` is true then ``dict`` keys that are not basic types | |
(``str``, ``int``, ``float``, ``bool``, ``None``) will be skipped | |
instead of raising a ``TypeError``. | |
If ``ensure_ascii`` is false, then the strings written to ``fp`` can | |
contain non-ASCII characters if they appear in strings contained in | |
``obj``. Otherwise, all such characters are escaped in JSON strings. | |
If ``check_circular`` is false, then the circular reference check | |
for container types will be skipped and a circular reference will | |
result in an ``RecursionError`` (or worse). | |
If ``allow_nan`` is false, then it will be a ``ValueError`` to | |
serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) | |
in strict compliance of the JSON specification, instead of using the | |
JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``). | |
If ``indent`` is a non-negative integer, then JSON array elements and | |
object members will be pretty-printed with that indent level. An indent | |
level of 0 will only insert newlines. ``None`` is the most compact | |
representation. | |
If specified, ``separators`` should be an ``(item_separator, key_separator)`` | |
tuple. The default is ``(', ', ': ')`` if *indent* is ``None`` and | |
``(',', ': ')`` otherwise. To get the most compact JSON representation, | |
you should specify ``(',', ':')`` to eliminate whitespace. | |
``default(obj)`` is a function that should return a serializable version | |
of obj or raise TypeError. The default simply raises TypeError. | |
If *sort_keys* is true (default: ``False``), then the output of | |
dictionaries will be sorted by key. | |
To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the | |
``.default()`` method to serialize additional types), specify it with | |
the ``cls`` kwarg; otherwise ``JSONEncoder`` is used. | |
""" | |
# cached encoder | |
if (not skipkeys and ensure_ascii and | |
check_circular and allow_nan and | |
cls is None and indent is None and separators is None and | |
default is None and not sort_keys and not kw): | |
iterable = _default_encoder.iterencode(obj) | |
else: | |
if cls is None: | |
cls = JSONEncoder | |
iterable = cls(skipkeys=skipkeys, ensure_ascii=ensure_ascii, | |
check_circular=check_circular, allow_nan=allow_nan, indent=indent, | |
separators=separators, | |
default=default, sort_keys=sort_keys, **kw).iterencode(obj) | |
# could accelerate with writelines in some versions of Python, at | |
# a debuggability cost | |
for chunk in iterable: | |
fp.write(chunk) | |
def dumps(obj, *, skipkeys=False, ensure_ascii=True, check_circular=True, | |
allow_nan=True, cls=None, indent=None, separators=None, | |
default=None, sort_keys=False, **kw): | |
"""Serialize ``obj`` to a JSON formatted ``str``. | |
If ``skipkeys`` is true then ``dict`` keys that are not basic types | |
(``str``, ``int``, ``float``, ``bool``, ``None``) will be skipped | |
instead of raising a ``TypeError``. | |
If ``ensure_ascii`` is false, then the return value can contain non-ASCII | |
characters if they appear in strings contained in ``obj``. Otherwise, all | |
such characters are escaped in JSON strings. | |
If ``check_circular`` is false, then the circular reference check | |
for container types will be skipped and a circular reference will | |
result in an ``RecursionError`` (or worse). | |
If ``allow_nan`` is false, then it will be a ``ValueError`` to | |
serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) in | |
strict compliance of the JSON specification, instead of using the | |
JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``). | |
If ``indent`` is a non-negative integer, then JSON array elements and | |
object members will be pretty-printed with that indent level. An indent | |
level of 0 will only insert newlines. ``None`` is the most compact | |
representation. | |
If specified, ``separators`` should be an ``(item_separator, key_separator)`` | |
tuple. The default is ``(', ', ': ')`` if *indent* is ``None`` and | |
``(',', ': ')`` otherwise. To get the most compact JSON representation, | |
you should specify ``(',', ':')`` to eliminate whitespace. | |
``default(obj)`` is a function that should return a serializable version | |
of obj or raise TypeError. The default simply raises TypeError. | |
If *sort_keys* is true (default: ``False``), then the output of | |
dictionaries will be sorted by key. | |
To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the | |
``.default()`` method to serialize additional types), specify it with | |
the ``cls`` kwarg; otherwise ``JSONEncoder`` is used. | |
""" | |
# cached encoder | |
if (not skipkeys and ensure_ascii and | |
check_circular and allow_nan and | |
cls is None and indent is None and separators is None and | |
default is None and not sort_keys and not kw): | |
return _default_encoder.encode(obj) | |
if cls is None: | |
cls = JSONEncoder | |
return cls( | |
skipkeys=skipkeys, ensure_ascii=ensure_ascii, | |
check_circular=check_circular, allow_nan=allow_nan, indent=indent, | |
separators=separators, default=default, sort_keys=sort_keys, | |
**kw).encode(obj) | |
_default_decoder = JSONDecoder(object_hook=None, object_pairs_hook=None) | |
def detect_encoding(b): | |
bstartswith = b.startswith | |
if bstartswith((codecs.BOM_UTF32_BE, codecs.BOM_UTF32_LE)): | |
return 'utf-32' | |
if bstartswith((codecs.BOM_UTF16_BE, codecs.BOM_UTF16_LE)): | |
return 'utf-16' | |
if bstartswith(codecs.BOM_UTF8): | |
return 'utf-8-sig' | |
if len(b) >= 4: | |
if not b[0]: | |
# 00 00 -- -- - utf-32-be | |
# 00 XX -- -- - utf-16-be | |
return 'utf-16-be' if b[1] else 'utf-32-be' | |
if not b[1]: | |
# XX 00 00 00 - utf-32-le | |
# XX 00 00 XX - utf-16-le | |
# XX 00 XX -- - utf-16-le | |
return 'utf-16-le' if b[2] or b[3] else 'utf-32-le' | |
elif len(b) == 2: | |
if not b[0]: | |
# 00 XX - utf-16-be | |
return 'utf-16-be' | |
if not b[1]: | |
# XX 00 - utf-16-le | |
return 'utf-16-le' | |
# default | |
return 'utf-8' | |
def load(fp, *, cls=None, object_hook=None, parse_float=None, | |
parse_int=None, parse_constant=None, object_pairs_hook=None, **kw): | |
"""Deserialize ``fp`` (a ``.read()``-supporting file-like object containing | |
a JSON document) to a Python object. | |
``object_hook`` is an optional function that will be called with the | |
result of any object literal decode (a ``dict``). The return value of | |
``object_hook`` will be used instead of the ``dict``. This feature | |
can be used to implement custom decoders (e.g. JSON-RPC class hinting). | |
``object_pairs_hook`` is an optional function that will be called with the | |
result of any object literal decoded with an ordered list of pairs. The | |
return value of ``object_pairs_hook`` will be used instead of the ``dict``. | |
This feature can be used to implement custom decoders. If ``object_hook`` | |
is also defined, the ``object_pairs_hook`` takes priority. | |
To use a custom ``JSONDecoder`` subclass, specify it with the ``cls`` | |
kwarg; otherwise ``JSONDecoder`` is used. | |
""" | |
return loads(fp.read(), | |
cls=cls, object_hook=object_hook, | |
parse_float=parse_float, parse_int=parse_int, | |
parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw) | |
def loads(s, *, cls=None, object_hook=None, parse_float=None, | |
parse_int=None, parse_constant=None, object_pairs_hook=None, **kw): | |
"""Deserialize ``s`` (a ``str``, ``bytes`` or ``bytearray`` instance | |
containing a JSON document) to a Python object. | |
``object_hook`` is an optional function that will be called with the | |
result of any object literal decode (a ``dict``). The return value of | |
``object_hook`` will be used instead of the ``dict``. This feature | |
can be used to implement custom decoders (e.g. JSON-RPC class hinting). | |
``object_pairs_hook`` is an optional function that will be called with the | |
result of any object literal decoded with an ordered list of pairs. The | |
return value of ``object_pairs_hook`` will be used instead of the ``dict``. | |
This feature can be used to implement custom decoders. If ``object_hook`` | |
is also defined, the ``object_pairs_hook`` takes priority. | |
``parse_float``, if specified, will be called with the string | |
of every JSON float to be decoded. By default this is equivalent to | |
float(num_str). This can be used to use another datatype or parser | |
for JSON floats (e.g. decimal.Decimal). | |
``parse_int``, if specified, will be called with the string | |
of every JSON int to be decoded. By default this is equivalent to | |
int(num_str). This can be used to use another datatype or parser | |
for JSON integers (e.g. float). | |
``parse_constant``, if specified, will be called with one of the | |
following strings: -Infinity, Infinity, NaN. | |
This can be used to raise an exception if invalid JSON numbers | |
are encountered. | |
To use a custom ``JSONDecoder`` subclass, specify it with the ``cls`` | |
kwarg; otherwise ``JSONDecoder`` is used. | |
""" | |
if isinstance(s, str): | |
if s.startswith('\ufeff'): | |
raise JSONDecodeError("Unexpected UTF-8 BOM (decode using utf-8-sig)", | |
s, 0) | |
else: | |
if not isinstance(s, (bytes, bytearray)): | |
raise TypeError(f'the JSON object must be str, bytes or bytearray, ' | |
f'not {s.__class__.__name__}') | |
s = s.decode(detect_encoding(s), 'surrogatepass') | |
if (cls is None and object_hook is None and | |
parse_int is None and parse_float is None and | |
parse_constant is None and object_pairs_hook is None and not kw): | |
return _default_decoder.decode(s) | |
if cls is None: | |
cls = JSONDecoder | |
if object_hook is not None: | |
kw['object_hook'] = object_hook | |
if object_pairs_hook is not None: | |
kw['object_pairs_hook'] = object_pairs_hook | |
if parse_float is not None: | |
kw['parse_float'] = parse_float | |
if parse_int is not None: | |
kw['parse_int'] = parse_int | |
if parse_constant is not None: | |
kw['parse_constant'] = parse_constant | |
return cls(**kw).decode(s) | |