Question

I’d like to allow my users to be able to log in via email. I’ve seen examples of accomplishing this by writing a custom authentication back-end. I, however, would like to do this by inheriting the django.contrib.auth.forms.AuthenticationForm and adding a new field called email which on the clean_email method fetches the username from the User model and then passes it to the parent form.

I’ve tried doing this but I’ve failed miserably as I can’t seem to modify the request or populate the field value. This is what I’ve gotten so far.

class LoginForm(AuthenticationForm):
    email = forms.EmailField(
        required=True, label=_("Email")
    )

    def __init__(self, request=None, *args, **kwargs):
        super(LoginForm, self).__init__(
            request, *args, **kwargs
        )
        self.fields['username'].widget = forms.widgets.HiddenInput()

    def clean_email(self):
        user = User.objects.filter(email=self.cleaned_data['email'])
        if user:
            #self.fields['username'].value = user.username
            #return user.email
        else:
            raise forms.ValidationError(_("Incorrect email or password."))

Thanks.

Answer 1

You should use clean if you want to modify another field:

def clean(self):
    cleaned_data = self.cleaned_data
    user = User.objects.filter(email=cleaned_data['email'])
    if user:
        cleaned_data['username'] = user.username
    else:
        raise forms.ValidationError(_("Incorrect email or password."))
    return cleaned_data

And don’t forget that email isn’t unique in Django auth.