__init__.py revision 5821806d5e7f356e8fa4b058a389a808ea183019 
1r"""
2A simple, fast, extensible JSON encoder and decoder
3
4JSON (JavaScript Object Notation) <http://json.org> is a subset of
5JavaScript syntax (ECMA-262 3rd edition) used as a lightweight data
6interchange format.
7
8simplejson exposes an API familiar to uses of the standard library
9marshal and pickle modules.
10
11Encoding basic Python object hierarchies::
12
13    >>> import simplejson
14    >>> simplejson.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}])
15    '["foo", {"bar": ["baz", null, 1.0, 2]}]'
16    >>> print simplejson.dumps("\"foo\bar")
17    "\"foo\bar"
18    >>> print simplejson.dumps(u'\u1234')
19    "\u1234"
20    >>> print simplejson.dumps('\\')
21    "\\"
22    >>> print simplejson.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True)
23    {"a": 0, "b": 0, "c": 0}
24    >>> from StringIO import StringIO
25    >>> io = StringIO()
26    >>> simplejson.dump(['streaming API'], io)
27    >>> io.getvalue()
28    '["streaming API"]'
29
30Compact encoding::
31
32    >>> import simplejson
33    >>> simplejson.dumps([1,2,3,{'4': 5, '6': 7}], separators=(',',':'))
34    '[1,2,3,{"4":5,"6":7}]'
35
36Pretty printing::
37
38    >>> import simplejson
39    >>> print simplejson.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4)
40    {
41        "4": 5,
42        "6": 7
43    }
44
45Decoding JSON::
46
47    >>> import simplejson
48    >>> simplejson.loads('["foo", {"bar":["baz", null, 1.0, 2]}]')
49    [u'foo', {u'bar': [u'baz', None, 1.0, 2]}]
50    >>> simplejson.loads('"\\"foo\\bar"')
51    u'"foo\x08ar'
52    >>> from StringIO import StringIO
53    >>> io = StringIO('["streaming API"]')
54    >>> simplejson.load(io)
55    [u'streaming API']
56
57Specializing JSON object decoding::
58
59    >>> import simplejson
60    >>> def as_complex(dct):
61    ...     if '__complex__' in dct:
62    ...         return complex(dct['real'], dct['imag'])
63    ...     return dct
64    ...
65    >>> simplejson.loads('{"__complex__": true, "real": 1, "imag": 2}',
66    ...     object_hook=as_complex)
67    (1+2j)
68
69Extending JSONEncoder::
70
71    >>> import simplejson
72    >>> class ComplexEncoder(simplejson.JSONEncoder):
73    ...     def default(self, obj):
74    ...         if isinstance(obj, complex):
75    ...             return [obj.real, obj.imag]
76    ...         return simplejson.JSONEncoder.default(self, obj)
77    ...
78    >>> dumps(2 + 1j, cls=ComplexEncoder)
79    '[2.0, 1.0]'
80    >>> ComplexEncoder().encode(2 + 1j)
81    '[2.0, 1.0]'
82    >>> list(ComplexEncoder().iterencode(2 + 1j))
83    ['[', '2.0', ', ', '1.0', ']']
84
85
86Note that the JSON produced by this module's default settings
87is a subset of YAML, so it may be used as a serializer for that as well.
88"""
89__version__ = '1.7.3'
90__all__ = [
91    'dump', 'dumps', 'load', 'loads',
92    'JSONDecoder', 'JSONEncoder',
93]
94
95from decoder import JSONDecoder
96from encoder import JSONEncoder
97
98_default_encoder = JSONEncoder(
99    skipkeys=False,
100    ensure_ascii=True,
101    check_circular=True,
102    allow_nan=True,
103    indent=None,
104    separators=None,
105    encoding='utf-8'
106)
107
108def dump(obj, fp, skipkeys=False, ensure_ascii=True, check_circular=True,
109        allow_nan=True, cls=None, indent=None, separators=None,
110        encoding='utf-8', **kw):
111    """
112    Serialize ``obj`` as a JSON formatted stream to ``fp`` (a
113    ``.write()``-supporting file-like object).
114
115    If ``skipkeys`` is ``True`` then ``dict`` keys that are not basic types
116    (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``)
117    will be skipped instead of raising a ``TypeError``.
118
119    If ``ensure_ascii`` is ``False``, then the some chunks written to ``fp``
120    may be ``unicode`` instances, subject to normal Python ``str`` to
121    ``unicode`` coercion rules. Unless ``fp.write()`` explicitly
122    understands ``unicode`` (as in ``codecs.getwriter()``) this is likely
123    to cause an error.
124
125    If ``check_circular`` is ``False``, then the circular reference check
126    for container types will be skipped and a circular reference will
127    result in an ``OverflowError`` (or worse).
128
129    If ``allow_nan`` is ``False``, then it will be a ``ValueError`` to
130    serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``)
131    in strict compliance of the JSON specification, instead of using the
132    JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``).
133
134    If ``indent`` is a non-negative integer, then JSON array elements and object
135    members will be pretty-printed with that indent level. An indent level
136    of 0 will only insert newlines. ``None`` is the most compact representation.
137
138    If ``separators`` is an ``(item_separator, dict_separator)`` tuple
139    then it will be used instead of the default ``(', ', ': ')`` separators.
140    ``(',', ':')`` is the most compact JSON representation.
141
142    ``encoding`` is the character encoding for str instances, default is UTF-8.
143
144    To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the
145    ``.default()`` method to serialize additional types), specify it with
146    the ``cls`` kwarg.
147    """
148    # cached encoder
149    if (skipkeys is False and ensure_ascii is True and
150        check_circular is True and allow_nan is True and
151        cls is None and indent is None and separators is None and
152        encoding == 'utf-8' and not kw):
153        iterable = _default_encoder.iterencode(obj)
154    else:
155        if cls is None:
156            cls = JSONEncoder
157        iterable = cls(skipkeys=skipkeys, ensure_ascii=ensure_ascii,
158            check_circular=check_circular, allow_nan=allow_nan, indent=indent,
159            separators=separators, encoding=encoding, **kw).iterencode(obj)
160    # could accelerate with writelines in some versions of Python, at
161    # a debuggability cost
162    for chunk in iterable:
163        fp.write(chunk)
164
165
166def dumps(obj, skipkeys=False, ensure_ascii=True, check_circular=True,
167        allow_nan=True, cls=None, indent=None, separators=None,
168        encoding='utf-8', **kw):
169    """
170    Serialize ``obj`` to a JSON formatted ``str``.
171
172    If ``skipkeys`` is ``True`` then ``dict`` keys that are not basic types
173    (``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``)
174    will be skipped instead of raising a ``TypeError``.
175
176    If ``ensure_ascii`` is ``False``, then the return value will be a
177    ``unicode`` instance subject to normal Python ``str`` to ``unicode``
178    coercion rules instead of being escaped to an ASCII ``str``.
179
180    If ``check_circular`` is ``False``, then the circular reference check
181    for container types will be skipped and a circular reference will
182    result in an ``OverflowError`` (or worse).
183
184    If ``allow_nan`` is ``False``, then it will be a ``ValueError`` to
185    serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``) in
186    strict compliance of the JSON specification, instead of using the
187    JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``).
188
189    If ``indent`` is a non-negative integer, then JSON array elements and
190    object members will be pretty-printed with that indent level. An indent
191    level of 0 will only insert newlines. ``None`` is the most compact
192    representation.
193
194    If ``separators`` is an ``(item_separator, dict_separator)`` tuple
195    then it will be used instead of the default ``(', ', ': ')`` separators.
196    ``(',', ':')`` is the most compact JSON representation.
197
198    ``encoding`` is the character encoding for str instances, default is UTF-8.
199
200    To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the
201    ``.default()`` method to serialize additional types), specify it with
202    the ``cls`` kwarg.
203    """
204    # cached encoder
205    if (skipkeys is False and ensure_ascii is True and
206        check_circular is True and allow_nan is True and
207        cls is None and indent is None and separators is None and
208        encoding == 'utf-8' and not kw):
209        return _default_encoder.encode(obj)
210    if cls is None:
211        cls = JSONEncoder
212    return cls(
213        skipkeys=skipkeys, ensure_ascii=ensure_ascii,
214        check_circular=check_circular, allow_nan=allow_nan, indent=indent,
215        separators=separators, encoding=encoding,
216        **kw).encode(obj)
217
218_default_decoder = JSONDecoder(encoding=None, object_hook=None)
219
220def load(fp, encoding=None, cls=None, object_hook=None, **kw):
221    """
222    Deserialize ``fp`` (a ``.read()``-supporting file-like object containing
223    a JSON document) to a Python object.
224
225    If the contents of ``fp`` is encoded with an ASCII based encoding other
226    than utf-8 (e.g. latin-1), then an appropriate ``encoding`` name must
227    be specified. Encodings that are not ASCII based (such as UCS-2) are
228    not allowed, and should be wrapped with
229    ``codecs.getreader(fp)(encoding)``, or simply decoded to a ``unicode``
230    object and passed to ``loads()``
231
232    ``object_hook`` is an optional function that will be called with the
233    result of any object literal decode (a ``dict``). The return value of
234    ``object_hook`` will be used instead of the ``dict``. This feature
235    can be used to implement custom decoders (e.g. JSON-RPC class hinting).
236
237    To use a custom ``JSONDecoder`` subclass, specify it with the ``cls``
238    kwarg.
239    """
240    return loads(fp.read(),
241        encoding=encoding, cls=cls, object_hook=object_hook, **kw)
242
243def loads(s, encoding=None, cls=None, object_hook=None, **kw):
244    """
245    Deserialize ``s`` (a ``str`` or ``unicode`` instance containing a JSON
246    document) to a Python object.
247
248    If ``s`` is a ``str`` instance and is encoded with an ASCII based encoding
249    other than utf-8 (e.g. latin-1) then an appropriate ``encoding`` name
250    must be specified. Encodings that are not ASCII based (such as UCS-2)
251    are not allowed and should be decoded to ``unicode`` first.
252
253    ``object_hook`` is an optional function that will be called with the
254    result of any object literal decode (a ``dict``). The return value of
255    ``object_hook`` will be used instead of the ``dict``. This feature
256    can be used to implement custom decoders (e.g. JSON-RPC class hinting).
257
258    To use a custom ``JSONDecoder`` subclass, specify it with the ``cls``
259    kwarg.
260    """
261    if cls is None and encoding is None and object_hook is None and not kw:
262        return _default_decoder.decode(s)
263    if cls is None:
264        cls = JSONDecoder
265    if object_hook is not None:
266        kw['object_hook'] = object_hook
267    return cls(encoding=encoding, **kw).decode(s)
268
269def read(s):
270    """
271    json-py API compatibility hook. Use loads(s) instead.
272    """
273    import warnings
274    warnings.warn("simplejson.loads(s) should be used instead of read(s)",
275        DeprecationWarning)
276    return loads(s)
277
278def write(obj):
279    """
280    json-py API compatibility hook. Use dumps(s) instead.
281    """
282    import warnings
283    warnings.warn("simplejson.dumps(s) should be used instead of write(s)",
284        DeprecationWarning)
285    return dumps(obj)
286
287
288