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Diffstat (limited to 'simplejson/__init__.py')
| -rw-r--r-- | simplejson/__init__.py | 318 |
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diff --git a/simplejson/__init__.py b/simplejson/__init__.py new file mode 100644 index 0000000..d5b4d39 --- /dev/null +++ b/simplejson/__init__.py @@ -0,0 +1,318 @@ +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:`simplejson` 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 simplejson as 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 simplejson as json + >>> json.dumps([1,2,3,{'4': 5, '6': 7}], separators=(',',':')) + '[1,2,3,{"4":5,"6":7}]' + +Pretty printing:: + + >>> import simplejson as json + >>> s = json.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4) + >>> print '\n'.join([l.rstrip() for l in s.splitlines()]) + { + "4": 5, + "6": 7 + } + +Decoding JSON:: + + >>> import simplejson as 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 simplejson as 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) + >>> import decimal + >>> json.loads('1.1', parse_float=decimal.Decimal) == decimal.Decimal('1.1') + True + +Specializing JSON object encoding:: + + >>> import simplejson as 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 simplejson.tool from the shell to validate and pretty-print:: + + $ echo '{"json":"obj"}' | python -m simplejson.tool + { + "json": "obj" + } + $ echo '{ 1.2:3.4}' | python -m simplejson.tool + Expecting property name: line 1 column 2 (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, **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 false, then the some chunks written to ``fp`` + may be ``unicode`` instances, subject to normal Python ``str`` to + ``unicode`` coercion rules. 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. + + 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. + + To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the + ``.default()`` method to serialize additional types), specify it with + the ``cls`` kwarg. + + """ + # 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 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, **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, **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, then the return value will be a + ``unicode`` instance subject to normal Python ``str`` to ``unicode`` + coercion rules instead of being escaped to an ASCII ``str``. + + 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 ``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. + + To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the + ``.default()`` method to serialize additional types), specify it with + the ``cls`` kwarg. + + """ + # 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 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, + **kw).encode(obj) + + +_default_decoder = JSONDecoder(encoding=None, object_hook=None) + + +def load(fp, encoding=None, cls=None, object_hook=None, parse_float=None, + parse_int=None, parse_constant=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). + + To use a custom ``JSONDecoder`` subclass, specify it with the ``cls`` + kwarg. + + """ + return loads(fp.read(), + encoding=encoding, cls=cls, object_hook=object_hook, + parse_float=parse_float, parse_int=parse_int, + parse_constant=parse_constant, **kw) + + +def loads(s, encoding=None, cls=None, object_hook=None, parse_float=None, + parse_int=None, parse_constant=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). + + ``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. + + """ + 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 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 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) |