python模块：json

 r"""JSON (JavaScript Object Notation) <http://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
     >>> from collections import OrderedDict
     >>> mydict = OrderedDict([('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(repr(obj) + " 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 <bob@redivi.com>'

 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 ``OverflowError`` (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 ``OverflowError`` (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 that rely on the
     order that the key and value pairs are decoded (for example,
     collections.OrderedDict will remember the order of insertion). 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, *, encoding=None, 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 that rely on the
     order that the key and value pairs are decoded (for example,
     collections.OrderedDict will remember the order of insertion). 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.

     The ``encoding`` argument is ignored and deprecated.

     """
     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('the JSON object must be str, bytes or bytearray, '
                             'not {!r}'.format(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)

python:json