jsonschema is an implementation of JSON Schema
for Python (supporting 2.6+ including Python 3).
>>> 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'- Full support for Draft 3 and Draft 4 of the schema.
- Lazy validation that can iteratively report all validation errors.
- Small and extensible
- Programmatic querying of which properties or items failed validation.
v2.3.0 removes the (improper) limitation of format to strings. It also
adds the jsonschema.exceptions.best_match
function which can be used to guess at the best matching single validation
error for a given instance.
>>> 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).
jsonschema uses the wonderful Tox 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.
There's a mailing list for this implementation on Google Groups.
Please join, and feel free to send questions there.
I'm Julian Berman.
jsonschema is on GitHub.
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 or via Google Wallet with the email in my GitHub profile.