Multiple attribute fields for the class attribute

Like it shown in the example:

class UserSchema(Schema):
    name = fields.String()
    email_addr = fields.String(attribute="email")
    date_created = fields.DateTime(attribute="created_at")

user = User('Keith', email='[e-mail]')
ser = UserSchema()
result = ser.dump(user)
pprint(result)
# {'name': 'Keith',
#  'email_addr': '[e-mail]',
#  'date_created': '2014-08-17T14:58:57.600623+00:00'}

It would be great to be able to specify multiple attributes like it done in golang tags. https://stackoverflow.com/questions/18635671/how-to-define-multiple-name-tags-in-a-struct

something like this:

class UserSchema(Schema):
    name = fields.String()
    email_addr = fields.String(attributes=("email", "e-mail"))
    date_created = fields.DateTime(attribute="created_at")

user = User('Keith', email='[e-mail]')
ser = UserSchema()
result = ser.dump(user)
pprint(result)
# {'name': 'Keith',
#  'email_addr': '[e-mail]',
#  'date_created': '2014-08-17T14:58:57.600623+00:00'}

user = User('Keith', e-mail='[e-mail]')
ser = UserSchema()
result = ser.dump(user)
pprint(result)
# {'name': 'Keith',
#  'email_addr': '[e-mail]',
#  'date_created': '2014-08-17T14:58:57.600623+00:00'}

Marshmallow already extensively used in testing, but this addition will open a new horizon for testing (especially in comparators related area)

If it sounds reasonable I could dig into it.

[lafrech]

OK, but what would be the logic from the Field point of view? Pick the first attribute of the list that holds a value?

The feature you’re asking for would have an undefined behaviour when dumping if both attributes are in the object.

You should use different schemas for this use case.

[LaserPhaser]

In testing, you usually have to map the data from different sources like databases/API. This proposal is like some kind of such mapper.

The feature you’re asking for would have an undefined behaviour when dumping if both attributes are in the object.

Actually, we can just throw a custom exception.

You should use different schemas for this use case.

I’ve got your point if it will break marshmallow ideology let’s just close this issue.