| 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 the externally maintained |
| version of the :mod:`json` library contained in Python 2.6, but maintains |
| compatibility with Python 2.4 and Python 2.5 and (currently) has |
| significant performance advantages, even without using the optional C |
| extension for speedups. |
| |
| 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(u'\u1234') |
| "\u1234" |
| >>> print json.dumps('\\') |
| "\\" |
| >>> print json.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True) |
| {"a": 0, "b": 0, "c": 0} |
| >>> from StringIO import StringIO |
| >>> io = StringIO() |
| >>> json.dump(['streaming API'], io) |
| >>> io.getvalue() |
| '["streaming API"]' |
| |
| Compact encoding:: |
| |
| >>> import json |
| >>> json.dumps([1,2,3,{'4': 5, '6': 7}], sort_keys=True, separators=(',',':')) |
| '[1,2,3,{"4":5,"6":7}]' |
| |
| Pretty printing:: |
| |
| >>> import json |
| >>> print json.dumps({'4': 5, '6': 7}, sort_keys=True, |
| ... indent=4, separators=(',', ': ')) |
| { |
| "4": 5, |
| "6": 7 |
| } |
| |
| Decoding JSON:: |
| |
| >>> import json |
| >>> obj = [u'foo', {u'bar': [u'baz', None, 1.0, 2]}] |
| >>> json.loads('["foo", {"bar":["baz", null, 1.0, 2]}]') == obj |
| True |
| >>> json.loads('"\\"foo\\bar"') == u'"foo\x08ar' |
| True |
| >>> from StringIO 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(o) + " 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', 'JSONEncoder', |
| ] |
| |
| __author__ = 'Bob Ippolito <bob@redivi.com>' |
| |
| from .decoder import JSONDecoder |
| from .encoder import JSONEncoder |
| |
| _default_encoder = JSONEncoder( |
| skipkeys=False, |
| ensure_ascii=True, |
| check_circular=True, |
| allow_nan=True, |
| indent=None, |
| separators=None, |
| encoding='utf-8', |
| default=None, |
| ) |
| |
| def dump(obj, fp, skipkeys=False, ensure_ascii=True, check_circular=True, |
| allow_nan=True, cls=None, indent=None, separators=None, |
| encoding='utf-8', 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``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``) |
| will be skipped instead of raising a ``TypeError``. |
| |
| If ``ensure_ascii`` is true (the default), all non-ASCII characters in the |
| output are escaped with ``\uXXXX`` sequences, and the result is a ``str`` |
| instance consisting of ASCII characters only. If ``ensure_ascii`` is |
| ``False``, some chunks written to ``fp`` may be ``unicode`` instances. |
| This usually happens because the input contains unicode strings or the |
| ``encoding`` parameter is used. Unless ``fp.write()`` explicitly |
| understands ``unicode`` (as in ``codecs.getwriter``) this is likely to |
| cause an error. |
| |
| 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. Since the default item separator is ``', '``, the |
| output might include trailing whitespace when ``indent`` is specified. |
| You can use ``separators=(',', ': ')`` to avoid this. |
| |
| If ``separators`` is an ``(item_separator, dict_separator)`` tuple |
| then it will be used instead of the default ``(', ', ': ')`` separators. |
| ``(',', ':')`` is the most compact JSON representation. |
| |
| ``encoding`` is the character encoding for str instances, default is UTF-8. |
| |
| ``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 |
| encoding == 'utf-8' 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, encoding=encoding, |
| 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, |
| encoding='utf-8', default=None, sort_keys=False, **kw): |
| """Serialize ``obj`` to a JSON formatted ``str``. |
| |
| If ``skipkeys`` is false then ``dict`` keys that are not basic types |
| (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``) |
| will be skipped instead of raising a ``TypeError``. |
| |
| If ``ensure_ascii`` is false, all non-ASCII characters are not escaped, and |
| the return value may be a ``unicode`` instance. See ``dump`` for details. |
| |
| 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. Since the default item separator is ``', '``, the |
| output might include trailing whitespace when ``indent`` is specified. |
| You can use ``separators=(',', ': ')`` to avoid this. |
| |
| If ``separators`` is an ``(item_separator, dict_separator)`` tuple |
| then it will be used instead of the default ``(', ', ': ')`` separators. |
| ``(',', ':')`` is the most compact JSON representation. |
| |
| ``encoding`` is the character encoding for str instances, default is UTF-8. |
| |
| ``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 |
| encoding == 'utf-8' 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, encoding=encoding, default=default, |
| sort_keys=sort_keys, **kw).encode(obj) |
| |
| |
| _default_decoder = JSONDecoder(encoding=None, object_hook=None, |
| object_pairs_hook=None) |
| |
| |
| def load(fp, encoding=None, 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. |
| |
| If the contents of ``fp`` is encoded with an ASCII based encoding other |
| than utf-8 (e.g. latin-1), then an appropriate ``encoding`` name must |
| be specified. Encodings that are not ASCII based (such as UCS-2) are |
| not allowed, and should be wrapped with |
| ``codecs.getreader(fp)(encoding)``, or simply decoded to a ``unicode`` |
| object and passed to ``loads()`` |
| |
| ``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(), |
| encoding=encoding, 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`` or ``unicode`` instance containing a JSON |
| document) to a Python object. |
| |
| If ``s`` is a ``str`` instance and is encoded with an ASCII based encoding |
| other than utf-8 (e.g. latin-1) then an appropriate ``encoding`` name |
| must be specified. Encodings that are not ASCII based (such as UCS-2) |
| are not allowed and should be decoded to ``unicode`` first. |
| |
| ``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, null, true, false. |
| 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 (cls is None and encoding 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(encoding=encoding, **kw).decode(s) |
