Question

I use the django.auth system and I’ve this:

class RegisterForm(UserCreationForm):
    username = forms.RegexField(label= "Username" , max_length = 30, regex = r'^[\w]+$', error_messages = {'invalid': "This value may contain only letters, numbers and _ characters."})
    email = forms.EmailField(label = "Email")
    first_name = forms.CharField(label = "First name", required = False)
    last_name = forms.CharField(label = "Last name", required = False)

    class Meta:
        model = User
        fields = ("username", "first_name", "last_name", "email", )

    def save(self, commit = True):
        user = super(RegisterForm, self).save(commit = False)
        user.first_name = self.cleaned_data["first_name"]
        user.last_name = self.cleaned_data["last_name"]
        user.email = self.cleaned_data["email"]
        if commit:
            user.save()
        return user

I want to set emails as uniques and check the form for this validation. How can I do it?

Answer 1

add this to your form. But this isn’t perfect way. race condition is available by only using this form. I recommend you to add unique constraint at db level.

def clean_email(self):
    data = self.cleaned_data['email']
    if User.objects.filter(email=data).exists():
        raise forms.ValidationError("This email already used")
    return data

SQL to add unique constraint:

ALTER TABLE auth_user ADD UNIQUE (email)