Custom form validation

Question

I have a pretty simple form:

from django import forms  class InitialSignupForm(forms.Form):     email = forms.EmailField()     password = forms.CharField(max_length=255, widget = forms.PasswordInput)     password_repeat = forms.CharField(max_length=255, widget = forms.PasswordInput)      def clean_message(self):         email = self.clean_data.get('email', '')         password = self.clean_data.get('password', '')         password_repeat = self.clean_data.get('password_repeat', '')          try:             User.objects.get(email_address = email)             raise forms.ValidationError("Email taken.")         except User.DoesNotExist:             pass          if password != password_repeat:             raise forms.ValidationError("The passwords don't match.") 

Is this how custom form validation is done? I need to evaluate on email that no users currently exist with that email address. I also need to evaluate that password and password_repeat match. How can I go about doing this?

Answer 1

To validate a single field on it's own you can use a clean_FIELDNAME() method in your form, so for email:

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

then for co-dependant fields that rely on each other, you can overwrite the forms clean() method which is run after all the fields (like email above) have been validated individually:

def clean(self):     form_data = self.cleaned_data     if form_data['password'] != form_data['password_repeat']:         self._errors["password"] = ["Password do not match"] # Will raise a error message         del form_data['password']     return form_data 

I'm not sure where you got clean_message() from, but that looks like it is a validation method made for a message field which doesn't seem to exist in your form.

Have a read through this for more details:

https://docs.djangoproject.com/en/dev/ref/forms/validation/