Input validation

simple_validation.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#

import json
from jsonschema import validate


class Greeting(object):

    SCHEMA = {
        "type": "object",
        "properties": {
            "greeting": {
                "enum": [
                    "Good morning",
                    "Good afternoon",
                    "Good evening",
                    "Good night"
                ],
                "type": "string"
            },

            "name": {
                "type": "string"
            },
            "title": {
                "type": "string"
            }
         },
        "additionalProperties": False,
        "required": [
            "greeting",
            "title",
            "name"
        ]
    }

    def __init__(self, data):

        self.text = data
        self.json = self._processResponse(data)

    def _processResponse(self, data):

        j = json.loads(data)
        validate(j, self.SCHEMA)
        return j

    def __str__(self):

        return "<Greeting(greeting='%s', title='%s', name='%s')>" % (self.json["greeting"], self.json["title"], self.json["name"])


def main():

    print(Greeting(r'{"greeting": "Good morning", "title": "Mr.", "name": "Bean"}'))
    print Greeting.SCHEMA


if __name__ == "__main__":
    main()

 $ python demo.py 
<Greeting(greeting='Good morning', title='Mr.', name='Bean')>
{'additionalProperties': False, 'required': ['greeting', 'title', 'name'], 'type': 'object', 'properties': {'title': {'type': 'string'}, 'greeting': {'enum': ['Good morning', 'Good afternoon', 'Good evening', 'Good night'], 'type': 'string'}, 'name': {'type': 'string'}}}