CODEWITHSUNDEEP
pythonflaskflask-sqlalchemyflask-restful
pl-jay
pl-jay

Reputation: 1100

StatementError for JSON serializer

Here I have simple rest API endpoints to create passenger object with the following model,

 class PassengerModel(db.Model):

    __tablename__ = 'passenger'

    ps_id          = db.Column(db.Integer, primary_key=True, autoincrement=True)
    ps_token_id    = db.Column(db.String(120),unique=True, nullable=False)
    passenger_name = db.Column(db.String(50),unique=True, nullable=False)
    passenger_email= db.Column(db.String(120),unique=True, nullable=False)
    prof_pic       = db.Column(db.String(120),unique=True, nullable=False)
    is_ontrip      = db.Column(db.Boolean, nullable=True)
    created        = db.Column(db.DateTime, default=datetime.datetime.utcnow,nullable=True)
    updated        = db.Column(db.DateTime,nullable=True)

and resource.py looks like this,


passenger_parser = reqparse.RequestParser()

passenger_parser.add_argument('ps_token_id')
passenger_parser.add_argument('passenger_name')
passenger_parser.add_argument('passenger_email')
passenger_parser.add_argument('prof_pic')
passenger_parser.add_argument('is_ontrip')
passenger_parser.add_argument('created')
passenger_parser.add_argument('updated')

class PassengerRegistration(Resource):
    def post(self):
        data = passenger_parser.parse_args()

        if PassengerModel.find_by_email(data['passenger_email']):
            return {'message': 'User {} already exists'.format(data['passenger_name'])}

        new_passenger = PassengerModel(
            ps_token_id     = data['ps_token_id'],
            passenger_name  = data['passenger_name'],
            passenger_email = data['passenger_email'],
            prof_pic        = data['prof_pic'],
            is_ontrip       = data['is_ontrip']
        )

        try:
            new_passenger.save_to_db()
            return {'message': 'passenger {} created'.format(data['passenger_name'])}
        except Exception as e:
            return {'message': 'Something went wrong', 'error': e}, 500

and once i tried to create new passenger object with a postman with the following error,

 {
    "ps_token_id":"1@asdsd",
    "passenger_name":"vAAaA",
    "passenger_email":"[email protected]",
    "prof_pic":"asdasdv",
    "is_ontrip":"False"
}

it returns this error,

TypeError: Object of type StatementError is not JSON serializable

for is_ontrip i have tried 0 and 1, true, false with braces and without braces. everytime it gives the above error.

What I'm done wrong here?

Upvotes: 0

Views: 54

Answers (1)

djnz
djnz

Reputation: 2050

Something is going wrong when you call new_passenger.save_to_db(), which results in a SqlAlchemy StatementError.

This cannot be serialized to JSON, so you will need to provide a serializable type, for example, a string:

... 'error': str(e)}, 500

Or to access the StatementError specific attributes, add a separate except:

...
except StatementError as se:
    return {'message': 'DB error', 'error': str(se), 'statement': se.statement}, 500

Upvotes: 1

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