Error handling

Oblate features a rich and customizable errors handling system.

Take for example, the User schema we defined earlier:

class User(oblate.Schema):
    id = fields.Integer()
    username = fields.String()
    is_employee = fields.Boolean(default=False)

User({'id': 'invalid integer'})

Note that we have not provided username which is a required field and id is supposed to be an integer, not a string. In this case, we get the following error which properly indicates the causative fields:

oblate.exceptions.ValidationError:
│
│ 2 validation errors in schema 'User'
│
└── In field id:
    └── Value of this field must be an integer
│
└── In field username:
    └── This field is required.

This error can also be converted to a “raw” format which is useful for, lets say, REST APIs:

try:
    User({'id': 'invalid integer'})
except oblate.ValidationError as error:
    print(error.raw())

Here’s the result:

{
    'id': ['Value of this field must be an integer'],
    'username': ['This field is required.']
}

This “raw format” is fully customizable to suit any use case.