Unique flag not reflected in WTForms validation

[sebdah]

It seems like the unique flag in MongoEngine is not reflected properly in the WTForms validation. I have a model like this (where the email is unique):

class User(database.Document):
    """ User model """
    email = database.EmailField(required=True, unique=True)
    first_name = database.StringField(required=True, max_length=30)
    last_name = database.StringField(required=True, max_length=30)
    password = database.StringField(required=True)
    is_active = database.BooleanField(default=False)
    is_authenticated = database.BooleanField(default=False)

But when I save this I get a mongoengine.errors.NotUniqueError from MongoEngine. I expected to get an error message from the form validation instead.

[lafrech]

Validation takes place at field level. The form itself can't tell if the document is unique. It would need to query the DB. That's not something WTForms does.

I've been facing the same issue. For now, I've left it aside and I catch NotUniqueError in the controller, but perhaps I could setup a function to query the DB and wrap this into a custom validator.

Suggestions welcome.

[wojcikstefan]

Agreed w/ @lafrech that this is not something that the form validation should deal with. Catching mongoengine.errors.NotUniqueError and then responding with a validation error message sounds like a perfectly fine approach.