==========
jsonschema
==========

``jsonschema`` is an implementation of `JSON Schema <http://json-schema.org>`_
for Python (supporting 2.6+ including Python 3).

.. code-block:: python

    >>> from jsonschema import validate

    >>> # A sample schema, like what we'd get from json.load()
    >>> schema = {
    ...     "type" : "object",
    ...     "properties" : {
    ...         "price" : {"type" : "number"},
    ...         "name" : {"type" : "string"},
    ...     },
    ... }

    >>> # If no exception is raised by validate(), the instance is valid.
    >>> validate({"name" : "Eggs", "price" : 34.99}, schema)

    >>> validate(
    ...     {"name" : "Eggs", "price" : "Invalid"}, schema
    ... )                                   # doctest: +IGNORE_EXCEPTION_DETAIL
    Traceback (most recent call last):
        ...
    ValidationError: 'Invalid' is not of type 'number'


Features
--------

* Full support for
  `Draft 3 <https://python-jsonschema.readthedocs.org/en/latest/validate.html#jsonschema.Draft3Validator>`_
  **and** `Draft 4 <https://python-jsonschema.readthedocs.org/en/latest/validate.html#jsonschema.Draft4Validator>`_
  of the schema.

* `Lazy validation <https://python-jsonschema.readthedocs.org/en/latest/validate.html#jsonschema.IValidator.iter_errors>`_
  that can iteratively report *all* validation errors.

* Small and extensible

* `Programmatic querying <https://python-jsonschema.readthedocs.org/en/latest/errors.html#module-jsonschema>`_
  of which properties or items failed validation.


Release Notes
-------------

``v2.3.0`` removes the (improper) limitation of ``format`` to strings. It also
adds the `jsonschema.exceptions.best_match <https://python-jsonschema.readthedocs.org/en/latest/errors/#best-match-and-by-relevance>`_
function which can be used to guess at the best matching single validation
error for a given instance.


.. code-block:: python

    >>> from jsonschema.validators import Draft4Validator
    >>> from jsonschema.exceptions import best_match

    >>> schema = {
    ...     "properties" : {
    ...         "foo" : {"type" : "string"},
    ...         "bar" : {"properties" : {"baz": {"type": "string"}}},
    ...     },
    ... }
    >>> instance = {"foo" : 12, "bar": {"baz" : 19}}
    >>> print(best_match(Draft4Validator(schema).iter_errors(instance)).path)
    deque(['foo'])


where the error closer to the top of the instance in ``foo`` was selected
as being more relevant.

Also, URI references are now properly rejected by the URI format validator
(i.e., it now only accepts full URIs, as defined in the specification).


Running the Test Suite
----------------------

``jsonschema`` uses the wonderful `Tox <http://tox.readthedocs.org>`_ for its
test suite. (It really is wonderful, if for some reason you haven't heard of
it, you really should use it for your projects).

Assuming you have ``tox`` installed (perhaps via ``pip install tox`` or your
package manager), just run ``tox`` in the directory of your source checkout to
run ``jsonschema``'s test suite on all of the versions of Python ``jsonschema``
supports. Note that you'll need to have all of those versions installed in
order to run the tests on each of them, otherwise ``tox`` will skip (and fail)
the tests on that version.

Of course you're also free to just run the tests on a single version with your
favorite test runner. The tests live in the ``jsonschema.tests`` package.


Community
---------

There's a `mailing list <https://groups.google.com/forum/#!forum/jsonschema>`_
for this implementation on Google Groups.

Please join, and feel free to send questions there.


Contributing
------------

I'm Julian Berman.

``jsonschema`` is on `GitHub <http://github.com/Julian/jsonschema>`_.

Get in touch, via GitHub or otherwise, if you've got something to contribute,
it'd be most welcome!

You can also generally find me on Freenode (nick: ``tos9``) in various
channels, including ``#python``.

If you feel overwhelmingly grateful, you can woo me with beer money on
`Gittip <https://www.gittip.com/Julian/>`_ or via Google Wallet with the email
in my GitHub profile.