gistfile1.txt

from functools import wraps
import json
from pyramid.httpexceptions import HTTPBadRequest
import validictory

def validate_json(inbound_schema=None, outbound_schema=None):
    """
    Validate the request's JSON input and output using JSON schemas 
    Based on http://www.alexconrad.org/2013/02/loggingexception.html.

    Return ``HTTPBadRequest`` on error.

    It will ensure:
    - request Content-Type is ``application/json``
    - JSON input (request.body) validates against the given JSON ``inbound_schema``
      and output validates against the given JSON ``outbound_schema``
    - provide the parsed JSON data through ``request.json``

    """
    def decorator(func):
        @wraps(func)
        def wrapper(view):

            request = view.request
            error = None
            if inbound_schema:
                try:
                    if request.environ['CONTENT_TYPE'] != 'application/json':
                        msg = 'Request Content-Type must be application/json'
                        raise ValueError(msg)
                    data = json.loads(unicode(request.body))
                    validictory.validate(data, inbound_schema)
                except ValueError as err:
                    error = {'error': str(err)}
                except validictory.ValidationError as err:
                    error = {'error': "Invalid JSON: %s" % err}

                if error is not None:
                    return HTTPBadRequest(body=json.dumps(error),
                                          content_type='application/json')
                view.request.json = data

            result = func(view)
            if outbound_schema:
                validictory.validate(result, outbound_schema)


            return result
        return wrapper
    return decorator