Overview

Validating anything can get really messy. JSON being one of the most used formats for data exchange, incoming aims at solving the problem of validating JSON with structure and ease.

incoming is a small framework for validating JSON. It’s up to you where and how to use it. A common use-case (and the primary reason why I wrote this framework) is validating incoming JSON when writing HTTP servers.

Installation

Installation is simple.

pip install incoming

Basic Usage

import json

from datetime import date
from incoming import datatypes, PayloadValidator


class MovieValidator(PayloadValidator):
    name = datatypes.String()
    rating = datatypes.Function(
        'validate_rating',
        error='Rating must be in between 1 and 10.',
    )
    actors = datatypes.Array()
    is_3d = datatypes.Boolean()
    release_year = datatypes.Function(
        'validate_release_year',
        error='Release year must be in between 1800 and current year.',
    )

    # validation method can be a regular method
    def validate_rating(self, val, *args, **kwargs):
        return isinstance(val, int) and val >= 1 and val <= 10

    # validation method can be a staticmethod as well
    @staticmethod
    def validate_release_year(val, *args, **kwargs):
        return all((
            isinstance(val, int),
            val >= 1800,
            val <= date.today().year,
        ))

payload = {
    'name': 'Avengers',
    'rating': 5,
    'actors': [
        'Robert Downey Jr.',
        'Samuel L. Jackson',
        'Scarlett Johansson',
        'Mark Ruffalo'
    ],
    'is_3d': True,
    'release_year': 2012
}
result, errors = MovieValidator().validate(payload)
assert result and errors is None, 'Validation failed.\n%s' % json.dumps(errors, indent=2)

payload = {
    'name': 'Avengers',
    'rating': 11,
    'actors': [
        'Robert Downey Jr.',
        'Samuel L. Jackson',
        'Scarlett Johansson',
        'Mark Ruffalo'
    ],
    'is_3d': 'True',
    'release_year': 9000
}
result, errors = MovieValidator().validate(payload)
assert result and errors is None, 'Validation failed.\n%s' % json.dumps(errors, indent=2)

If you run the above script, you will get:

Traceback (most recent call last):
  File "code.py", line 67, in <module>
    assert result and errors is None, 'Validation failed.\n%s' % json.dumps(errors, indent=2)
AssertionError: Validation failed.
{
  "rating": [
    "Rating must be in between 1 and 10."
  ],
  "is_3d": [
    "Invalid data. Expected a boolean value."
  ],
  "release_year": [
    "Release year must be in between 1800 and current year."
  ]
}

Documentation

Documentation is available on Read The Docs.

Tests

Simply run:

python setup.py test

or:

py.test incoming

Contributors

• Vaidik Kapoor (Author)

• Dhruv Baldawa

• James Rowe

Licence

See LICENCE.

The MIT License (MIT)

Copyright (c) 2013 Vaidik Kapoor

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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