CODEWITHSUNDEEP
djangodjango-forms
Hassan Baig
Hassan Baig

Reputation: 15824

Manipulating Django form to show the correct validation error(s)

In a Django form, I'm getting users to input their usernames. The field is like so:

username = forms.RegexField(max_length=50,regex=re.compile('^[\w.@+-]+$'),\
        error_messages={'invalid': _("(tip: only use alphabets, numbers or @ _ . + - symbols)")})

Later, in the clean_username method, I also need to ensure users didn't include a whtiespace in the username. I do that like so:

def clean_username(self):
    username = self.cleaned_data['username']
    if ' ' in username:
        raise ValidationError("(tip: a username can't have whitespaces)")
    return username

The problem is that this validation error never appears, since whitespaces fail the prior regex check. I need to be able to show the whitespace related ValidationError separately. Moreover I also don't want to compromise on showing the relevant error if a user writes a regex failing username such as Bèndèr*.

What's the best way to fix this issue? An illustrative example would be great. Thanks!

Upvotes: 1

Views: 185

Answers (1)

arie
arie

Reputation: 18972

So instead of using the RegexField I would probably either go with a CharField and a customized clean-method for the field, which handles the whitespace issue first and only checks the regex if the the whitespace check passed.

Or I would use a CharField and assign a custom validator first, that checks for the whitespaces, and additionally a RegexValidator

Something along these lines:

from django.core.exceptions import ValidationError
from django.core.validators import RegexValidator

def validate_whitespaces(value):
    if ' ' in value:
        raise ValidationError("Oops, a whitespace error occured.")

username = forms.CharField(
    max_length=50,
    validators=[
        validate_whitespaces,
        RegexValidator(
            regex='^[\w.@+-]+$',
            message='Only use valid chars ...'
        )
    ]
)

Upvotes: 2

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