Django ProEmailFormField

ProEmailFormField.py

from django import forms
from django.core.exceptions import ValidationError
import re



'''
pass a list of excluded domain names upon instantiation.
subclasses forms.EmailField, which validates against empty values, and that it is a correct email.
then validate_pro will check whether not part of the excluded domains.
I used an extra method as opposed to a custom validator because it seems to be difficult to know which validator is run first
and we do want the default email validator to run first because otherwise there is a chance that the regexp will fail and crash the site.
'''

class ProEmailField(forms.EmailField):
    
    def __init__(self, excludedDomain, **kwargs):
        self.exclude = excludedDomain
        super(ProEmailField, self).__init__(self,**kwargs)

    def validate_pro(self, value):
        domain = value.split('@')[1]
        if domain in self.exclude:
            raise ValidationError('it seems you have provided a %s address, please give us your professional email adress' % (domain))
        
    def clean(self, value):
        #please note the extra validate_pro method
        value = super(ProEmailField, self).clean(value)
        self.validate_pro(value)
        return value