Basic Usage

.. function:: dump(obj, fp[, skipkeys[, ensure_ascii[, check_circular[, allow_nan[, cls[, indent[, separators[, encoding[, default[, **kw]]]]]]]]]])

   Serialize *obj* as a JSON formatted stream to *fp* (a ``.write()``-supporting
   file-like object).

   If *skipkeys* is ``True`` (default: ``False``), then dict keys that are not
   of a basic type (:class:`str`, :class:`unicode`, :class:`int`, :class:`long`,
   :class:`float`, :class:`bool`, ``None``) will be skipped instead of raising a
   :exc:`TypeError`.

   If *ensure_ascii* is ``False`` (default: ``True``), then some chunks written
   to *fp* may be :class:`unicode` instances, subject to normal Python
   :class:`str` to :class:`unicode` coercion rules.  Unless ``fp.write()``
   explicitly understands :class:`unicode` (as in :func:`codecs.getwriter`) this
   is likely to cause an error.

   If *check_circular* is ``False`` (default: ``True``), then the circular
   reference check for container types will be skipped and a circular reference
   will result in an :exc:`OverflowError` (or worse).

   If *allow_nan* is ``False`` (default: ``True``), then it will be a
   :exc:`ValueError` to serialize out of range :class:`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`` (the default) selects 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 :exc:`TypeError`.  The default simply raises :exc:`TypeError`.

   To use a custom :class:`JSONEncoder` subclass (e.g. one that overrides the
   :meth:`default` method to serialize additional types), specify it with the
   *cls* kwarg.

.. function:: dumps(obj[, skipkeys[, ensure_ascii[, check_circular[, allow_nan[, cls[, indent[, separators[, encoding[, default[, **kw]]]]]]]]]])

   Serialize *obj* to a JSON formatted :class:`str`.

   If *ensure_ascii* is ``False``, then the return value will be a
   :class:`unicode` instance.  The other arguments have the same meaning as in
   :func:`dump`.

.. function:: load(fp[, encoding[, cls[, object_hook[, parse_float[, parse_int[, parse_constant[, **kw]]]]]]])

   Deserialize *fp* (a ``.read()``-supporting file-like object containing a JSON
   document) to a Python object.

   If the contents of *fp* are 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(encoding)(fp)``, or simply decoded
   to a :class:`unicode` object and passed to :func:`loads`.

   *object_hook* is an optional function that will be called with the result of
   any object literal decoded (a :class:`dict`).  The return value of
   *object_hook* will be used instead of the :class:`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. :class:`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. :class:`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 :class:`JSONDecoder` subclass, specify it with the ``cls``
   kwarg.  Additional keyword arguments will be passed to the constructor of the
   class.

.. function:: loads(s[, encoding[, cls[, object_hook[, parse_float[, parse_int[, parse_constant[, **kw]]]]]]])

   Deserialize *s* (a :class:`str` or :class:`unicode` instance containing a JSON
   document) to a Python object.

   If *s* is a :class:`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 :class:`unicode` first.

   The other arguments have the same meaning as in :func:`dump`.

Encoders and decoders

Simple JSON decoder.

Performs the following translations in decoding by default:

It also understands NaN, Infinity, and -Infinity as their corresponding float values, which is outside the JSON spec.

encoding determines the encoding used to interpret any :class:`str` objects decoded by this instance (UTF-8 by default). It has no effect when decoding :class:`unicode` objects.

Note that currently only encodings that are a superset of ASCII work, strings of other encodings should be passed in as :class:`unicode`.

object_hook, if specified, will be called with the result of every JSON object decoded and its return value will be used in place of the given :class:`dict`. This can be used to provide custom deserializations (e.g. to support 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. :class:`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. :class:`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.

.. method:: decode(s)

   Return the Python representation of *s* (a :class:`str` or
   :class:`unicode` instance containing a JSON document)

.. method:: raw_decode(s)

   Decode a JSON document from *s* (a :class:`str` or :class:`unicode`
   beginning with a JSON document) and return a 2-tuple of the Python
   representation and the index in *s* where the document ended.

   This can be used to decode a JSON document from a string that may have
   extraneous data at the end.

Extensible JSON encoder for Python data structures.

Supports the following objects and types by default:

To extend this to recognize other objects, subclass and implement a :meth:`default` method with another method that returns a serializable object for o if possible, otherwise it should call the superclass implementation (to raise :exc:`TypeError`).

If skipkeys is False (the default), then it is a :exc:`TypeError` to attempt encoding of keys that are not str, int, long, float or None. If skipkeys is True, such items are simply skipped.

If ensure_ascii is True (the default), the output is guaranteed to be :class:`str` objects with all incoming unicode characters escaped. If ensure_ascii is False, the output will be a unicode object.

If check_circular is True (the default), then lists, dicts, and custom encoded objects will be checked for circular references during encoding to prevent an infinite recursion (which would cause an :exc:`OverflowError`). Otherwise, no such check takes place.

If allow_nan is True (the default), then NaN, Infinity, and -Infinity will be encoded as such. This behavior is not JSON specification compliant, but is consistent with most JavaScript based encoders and decoders. Otherwise, it will be a :exc:`ValueError` to encode such floats.

If sort_keys is True (the default), then the output of dictionaries will be sorted by key; this is useful for regression tests to ensure that JSON serializations can be compared on a day-to-day basis.

If indent is a non-negative integer (it is None by default), 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 (', ', ': '). To get the most compact JSON representation, you should specify (',', ':') to eliminate whitespace.

If specified, default is a function that gets called for objects that can't otherwise be serialized. It should return a JSON encodable version of the object or raise a :exc:`TypeError`.

If encoding is not None, then all input strings will be transformed into unicode using that encoding prior to JSON-encoding. The default is UTF-8.

.. method:: default(o)

   Implement this method in a subclass such that it returns a serializable
   object for *o*, or calls the base implementation (to raise a
   :exc:`TypeError`).

   For example, to support arbitrary iterators, you could implement default
   like this::

      def default(self, o):
         try:
             iterable = iter(o)
         except TypeError:
             pass
         else:
             return list(iterable)
         return JSONEncoder.default(self, o)

.. method:: encode(o)

   Return a JSON string representation of a Python data structure, *o*.  For
   example::

     >>> JSONEncoder().encode({"foo": ["bar", "baz"]})
     '{"foo": ["bar", "baz"]}'

.. method:: iterencode(o)

   Encode the given object, *o*, and yield each string representation as
   available.  For example::

         for chunk in JSONEncoder().iterencode(bigobject):
             mysocket.write(chunk)