Package django :: Package utils :: Package simplejson

Package simplejson

A simple, fast, extensible JSON encoder and decoder

JSON (JavaScript Object Notation) <http://json.org> is a subset of JavaScript syntax (ECMA-262 3rd edition) used as a lightweight data interchange format.

simplejson exposes an API familiar to uses of the standard library marshal and pickle modules.

Encoding basic Python object hierarchies:

   >>> import simplejson
   >>> simplejson.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}])
   '["foo", {"bar": ["baz", null, 1.0, 2]}]'
   >>> print simplejson.dumps("\"foo\bar")
   "\"foo\bar"
   >>> print simplejson.dumps(u'\u1234')
   "\u1234"
   >>> print simplejson.dumps('\\')
   "\\"
   >>> print simplejson.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True)
   {"a": 0, "b": 0, "c": 0}
   >>> from StringIO import StringIO
   >>> io = StringIO()
   >>> simplejson.dump(['streaming API'], io)
   >>> io.getvalue()
   '["streaming API"]'

Compact encoding:

   >>> import simplejson
   >>> simplejson.dumps([1,2,3,{'4': 5, '6': 7}], separators=(',',':'))
   '[1,2,3,{"4":5,"6":7}]'

Pretty printing:

   >>> import simplejson
   >>> print simplejson.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4)
   {
       "4": 5, 
       "6": 7
   }

Decoding JSON:

   >>> import simplejson
   >>> simplejson.loads('["foo", {"bar":["baz", null, 1.0, 2]}]')
   [u'foo', {u'bar': [u'baz', None, 1.0, 2]}]
   >>> simplejson.loads('"\\"foo\\bar"')
   u'"foo\x08ar'
   >>> from StringIO import StringIO
   >>> io = StringIO('["streaming API"]')
   >>> simplejson.load(io)
   [u'streaming API']

Specializing JSON object decoding:

   >>> import simplejson
   >>> def as_complex(dct):
   ...     if '__complex__' in dct:
   ...         return complex(dct['real'], dct['imag'])
   ...     return dct
   ... 
   >>> simplejson.loads('{"__complex__": true, "real": 1, "imag": 2}',
   ...     object_hook=as_complex)
   (1+2j)
   >>> import decimal
   >>> simplejson.loads('1.1', parse_float=decimal.Decimal)
   Decimal("1.1")

Extending JSONEncoder:

   >>> import simplejson
   >>> class ComplexEncoder(simplejson.JSONEncoder):
   ...     def default(self, obj):
   ...         if isinstance(obj, complex):
   ...             return [obj.real, obj.imag]
   ...         return simplejson.JSONEncoder.default(self, obj)
   ... 
   >>> dumps(2 + 1j, cls=ComplexEncoder)
   '[2.0, 1.0]'
   >>> ComplexEncoder().encode(2 + 1j)
   '[2.0, 1.0]'
   >>> list(ComplexEncoder().iterencode(2 + 1j))
   ['[', '2.0', ', ', '1.0', ']']

Using simplejson from the shell to validate and pretty-print:

   $ echo '{"json":"obj"}' | python -msimplejson.tool
   {
       "json": "obj"
   }
   $ echo '{ 1.2:3.4}' | python -msimplejson.tool
   Expecting property name: line 1 column 2 (char 2)

Note that the JSON produced by this module's default settings is a subset of YAML, so it may be used as a serializer for that as well.

Version:

1.9.2

Submodules

[hide private]

django.utils.simplejson.decoder: Implementation of JSONDecoder
django.utils.simplejson.encoder: Implementation of JSONEncoder
django.utils.simplejson.scanner: Iterator based sre token scanner
django.utils.simplejson.tool: Using simplejson from the shell to validate and pretty-print:

Functions

[hide private]

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).

source code

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``.

source code

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.

source code

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.

source code

decode(s)
demjson, python-cjson API compatibility hook.

source code

encode(obj)
demjson, python-cjson compatibility hook.

source code

read(s)
jsonlib, JsonUtils, python-json, json-py API compatibility hook.

source code

write(obj)
jsonlib, JsonUtils, python-json, json-py API compatibility hook.

source code

Variables

[hide private]

JSONDecoder

JSONEncoder

_default_encoder = JSONEncoder(skipkeys= False, ensure_ascii= ...

_default_decoder = JSONDecoder(encoding= None, object_hook= None)

Function Details

[hide private]

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)

source code

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.

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)

source code

Serialize ``obj`` to a JSON formatted ``str``.

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 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 ``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.

load(fp, encoding=None, cls=None, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, **kw)

source code

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.

loads(s, encoding=None, cls=None, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, **kw)

source code

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.

``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.

decode(s)

source code

demjson, python-cjson API compatibility hook. Use loads(s) instead.

encode(obj)

source code

demjson, python-cjson compatibility hook. Use dumps(s) instead.

read(s)

source code

jsonlib, JsonUtils, python-json, json-py API compatibility hook. Use loads(s) instead.

write(obj)

source code

jsonlib, JsonUtils, python-json, json-py API compatibility hook. Use dumps(s) instead.

Variables Details

[hide private]

_default_encoder

Value:

JSONEncoder(skipkeys= False, ensure_ascii= True, check_circular= True,
 allow_nan= True, indent= None, separators= None, encoding= 'utf-8', d
efault= None,)