Question

I’m trying to validate that a submitted URL doesn’t already exist in the database.

The relevant parts of the Form class look like this:

from django.contrib.sites.models import Site class SignUpForm(forms.Form):     # ... Other fields ...     url = forms.URLField(label='URL for new site, eg: example.com')      def clean_url(self):         url = self.cleaned_data['url']         try:             a = Site.objects.get(domain=url)          except Site.DoesNotExist:             return url          else:             raise forms.ValidationError('That URL is already in the database.  Please submit a unique URL.')      def clean(self):         # Other form cleaning stuff.  I don't *think* this is causing the grief 

The problem is, regardless of what value I submit, I can’t raise the ValidationError. And if I do something like this in the clean_url() method:

if Site.objects.get(domain=url):     raise forms.ValidationError('That URL is already in the database.  Please submit a unique URL.') 

then I get a DoesNotExist error, even for URLs that already exist in the Database. Any ideas?

Answer 1

django channel in IRC saved me here. The problem was that the URLField.clean() does two things I wasn’t expecting:

1. If no URL scheme is present (eg, http://) the method prepends ‘http://’ to the url
2. the method also appends a trailing slash.

The results are returned and stored in the form’s cleaned_data. So I was checking cleaned_data['url'] expecting something like example.com and actually getting http://example.com/. Suffice to say, changing my clean_url() method to the following works:

def clean_url(self):         url = self.cleaned_data['url']                 bits = urlparse(url)         dom = bits[1]         try:             site=Site.objects.get(domain__iexact=dom)         except Site.DoesNotExist:             return dom         raise forms.ValidationError(u'That domain is already taken.  Please choose another')