253 lines
9.2 KiB
Python
253 lines
9.2 KiB
Python
r"""
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A simple, fast, extensible JSON encoder and decoder
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JSON (JavaScript Object Notation) <http://json.org> is a subset of
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JavaScript syntax (ECMA-262 3rd edition) used as a lightweight data
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interchange format.
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simplejson exposes an API familiar to uses of the standard library
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marshal and pickle modules.
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Encoding basic Python object hierarchies::
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>>> import simplejson
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>>> simplejson.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}])
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'["foo", {"bar": ["baz", null, 1.0, 2]}]'
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>>> print simplejson.dumps("\"foo\bar")
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"\"foo\bar"
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>>> print simplejson.dumps(u'\u1234')
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"\u1234"
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>>> print simplejson.dumps('\\')
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"\\"
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>>> print simplejson.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True)
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{"a": 0, "b": 0, "c": 0}
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>>> from StringIO import StringIO
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>>> io = StringIO()
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>>> simplejson.dump(['streaming API'], io)
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>>> io.getvalue()
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'["streaming API"]'
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Compact encoding::
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>>> import simplejson
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>>> simplejson.dumps([1,2,3,{'4': 5, '6': 7}], separators=(',',':'))
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'[1,2,3,{"4":5,"6":7}]'
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Pretty printing::
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>>> import simplejson
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>>> print simplejson.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4)
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{
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"4": 5,
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"6": 7
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}
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Decoding JSON::
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>>> import simplejson
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>>> simplejson.loads('["foo", {"bar":["baz", null, 1.0, 2]}]')
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[u'foo', {u'bar': [u'baz', None, 1.0, 2]}]
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>>> simplejson.loads('"\\"foo\\bar"')
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u'"foo\x08ar'
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>>> from StringIO import StringIO
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>>> io = StringIO('["streaming API"]')
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>>> simplejson.load(io)
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[u'streaming API']
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Specializing JSON object decoding::
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>>> import simplejson
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>>> def as_complex(dct):
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... if '__complex__' in dct:
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... return complex(dct['real'], dct['imag'])
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... return dct
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...
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>>> simplejson.loads('{"__complex__": true, "real": 1, "imag": 2}',
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... object_hook=as_complex)
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(1+2j)
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Extending JSONEncoder::
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>>> import simplejson
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>>> class ComplexEncoder(simplejson.JSONEncoder):
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... def default(self, obj):
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... if isinstance(obj, complex):
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... return [obj.real, obj.imag]
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... return simplejson.JSONEncoder.default(self, obj)
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...
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>>> dumps(2 + 1j, cls=ComplexEncoder)
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'[2.0, 1.0]'
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>>> ComplexEncoder().encode(2 + 1j)
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'[2.0, 1.0]'
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>>> list(ComplexEncoder().iterencode(2 + 1j))
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['[', '2.0', ', ', '1.0', ']']
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Note that the JSON produced by this module's default settings
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is a subset of YAML, so it may be used as a serializer for that as well.
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"""
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__version__ = '1.5'
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__all__ = [
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'dump', 'dumps', 'load', 'loads',
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'JSONDecoder', 'JSONEncoder',
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]
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from django.utils.simplejson.decoder import JSONDecoder
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from django.utils.simplejson.encoder import JSONEncoder
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def dump(obj, fp, skipkeys=False, ensure_ascii=True, check_circular=True,
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allow_nan=True, cls=None, indent=None, **kw):
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"""
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Serialize ``obj`` as a JSON formatted stream to ``fp`` (a
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``.write()``-supporting file-like object).
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If ``skipkeys`` is ``True`` then ``dict`` keys that are not basic types
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(``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``)
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will be skipped instead of raising a ``TypeError``.
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If ``ensure_ascii`` is ``False``, then the some chunks written to ``fp``
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may be ``unicode`` instances, subject to normal Python ``str`` to
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``unicode`` coercion rules. Unless ``fp.write()`` explicitly
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understands ``unicode`` (as in ``codecs.getwriter()``) this is likely
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to cause an error.
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If ``check_circular`` is ``False``, then the circular reference check
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for container types will be skipped and a circular reference will
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result in an ``OverflowError`` (or worse).
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If ``allow_nan`` is ``False``, then it will be a ``ValueError`` to
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serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``)
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in strict compliance of the JSON specification, instead of using the
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JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``).
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If ``indent`` is a non-negative integer, then JSON array elements and object
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members will be pretty-printed with that indent level. An indent level
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of 0 will only insert newlines. ``None`` is the most compact representation.
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To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the
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``.default()`` method to serialize additional types), specify it with
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the ``cls`` kwarg.
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"""
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if cls is None:
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cls = JSONEncoder
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iterable = cls(skipkeys=skipkeys, ensure_ascii=ensure_ascii,
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check_circular=check_circular, allow_nan=allow_nan, indent=indent,
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**kw).iterencode(obj)
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# could accelerate with writelines in some versions of Python, at
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# a debuggability cost
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for chunk in iterable:
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fp.write(chunk)
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def dumps(obj, skipkeys=False, ensure_ascii=True, check_circular=True,
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allow_nan=True, cls=None, indent=None, separators=None, **kw):
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"""
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Serialize ``obj`` to a JSON formatted ``str``.
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If ``skipkeys`` is ``True`` then ``dict`` keys that are not basic types
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(``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``)
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will be skipped instead of raising a ``TypeError``.
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If ``ensure_ascii`` is ``False``, then the return value will be a
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``unicode`` instance subject to normal Python ``str`` to ``unicode``
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coercion rules instead of being escaped to an ASCII ``str``.
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If ``check_circular`` is ``False``, then the circular reference check
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for container types will be skipped and a circular reference will
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result in an ``OverflowError`` (or worse).
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If ``allow_nan`` is ``False``, then it will be a ``ValueError`` to
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serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) in
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strict compliance of the JSON specification, instead of using the
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JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``).
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If ``indent`` is a non-negative integer, then JSON array elements and
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object members will be pretty-printed with that indent level. An indent
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level of 0 will only insert newlines. ``None`` is the most compact
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representation.
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If ``separators`` is an ``(item_separator, dict_separator)`` tuple
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then it will be used instead of the default ``(', ', ': ')`` separators.
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``(',', ':')`` is the most compact JSON representation.
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To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the
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``.default()`` method to serialize additional types), specify it with
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the ``cls`` kwarg.
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"""
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if cls is None:
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cls = JSONEncoder
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return cls(
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skipkeys=skipkeys, ensure_ascii=ensure_ascii,
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check_circular=check_circular, allow_nan=allow_nan, indent=indent,
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separators=separators,
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**kw).encode(obj)
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def load(fp, encoding=None, cls=None, object_hook=None, **kw):
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"""
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Deserialize ``fp`` (a ``.read()``-supporting file-like object containing
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a JSON document) to a Python object.
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If the contents of ``fp`` is encoded with an ASCII based encoding other
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than utf-8 (e.g. latin-1), then an appropriate ``encoding`` name must
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be specified. Encodings that are not ASCII based (such as UCS-2) are
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not allowed, and should be wrapped with
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``codecs.getreader(fp)(encoding)``, or simply decoded to a ``unicode``
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object and passed to ``loads()``
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``object_hook`` is an optional function that will be called with the
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result of any object literal decode (a ``dict``). The return value of
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``object_hook`` will be used instead of the ``dict``. This feature
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can be used to implement custom decoders (e.g. JSON-RPC class hinting).
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To use a custom ``JSONDecoder`` subclass, specify it with the ``cls``
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kwarg.
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"""
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if cls is None:
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cls = JSONDecoder
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if object_hook is not None:
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kw['object_hook'] = object_hook
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return cls(encoding=encoding, **kw).decode(fp.read())
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def loads(s, encoding=None, cls=None, object_hook=None, **kw):
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"""
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Deserialize ``s`` (a ``str`` or ``unicode`` instance containing a JSON
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document) to a Python object.
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If ``s`` is a ``str`` instance and is encoded with an ASCII based encoding
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other than utf-8 (e.g. latin-1) then an appropriate ``encoding`` name
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must be specified. Encodings that are not ASCII based (such as UCS-2)
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are not allowed and should be decoded to ``unicode`` first.
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``object_hook`` is an optional function that will be called with the
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result of any object literal decode (a ``dict``). The return value of
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``object_hook`` will be used instead of the ``dict``. This feature
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can be used to implement custom decoders (e.g. JSON-RPC class hinting).
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To use a custom ``JSONDecoder`` subclass, specify it with the ``cls``
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kwarg.
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"""
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if cls is None:
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cls = JSONDecoder
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if object_hook is not None:
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kw['object_hook'] = object_hook
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return cls(encoding=encoding, **kw).decode(s)
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def read(s):
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"""
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json-py API compatibility hook. Use loads(s) instead.
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"""
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import warnings
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warnings.warn("simplejson.loads(s) should be used instead of read(s)",
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DeprecationWarning)
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return loads(s)
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def write(obj):
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"""
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json-py API compatibility hook. Use dumps(s) instead.
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"""
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import warnings
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warnings.warn("simplejson.dumps(s) should be used instead of write(s)",
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DeprecationWarning)
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return dumps(obj)
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