Question

I created UserProfile (extends from User) and written to settings.py

 AUTH_PROFILE_MODULE = 'mainapp.UserProfile'.

When I delete UserProfile (from admin area) I would delete also User item.

I try delete user so self.user.delete(), but method delete (in UserProfile) don’t call. Why ?

This is my code:

class UserProfile(models.Model):
    avatar = models.ImageField(upload_to = settings.PATH_AVATARS, blank=True)
    url = models.URLField(blank=True)
    user = models.OneToOneField(User)

    def __unicode__(self):
        return self.user.username

    def delete(self, *args, **kwargs):
        self.user.delete()
        super(UserProfile, self).delete(*args, **kwargs)

Answer 1

First, to answer why “delete()” is not called from the admin. This statement is:

1. True in the case of deleting objects from the list view, ie. /admin/auth/user/ check some boxes then click Actions -> delete), this is because the delete() method of a queryset is called,
2. Wrong in the case of deleting an object from the change_form, ie. /admin/auth/user/1/ click on delete, this is where the delete() method of the object is called

That said, _delete signals are well supported. Here is how you can use it:

from django.db.models import signals

def delete_user(sender, instance=None, **kwargs):
    try:
        instance.user
    except User.DoesNotExist:
        pass
    else:
        instance.user.delete()
signals.post_delete.connect(delete_user, sender=UserProfile)

This is how i tested it:

In [1]: from django.contrib.auth.models import User; from testapp.models import UserProfile; User.objects.all().delete(); UserProfile.objects.all().delete()

In [2]: user=User(username='foo'); user.save()

In [3]: profile=UserProfile(user=user); profile.save()

In [4]: UserProfile.objects.all().delete()

In [5]: User.objects.all()
Out[5]: []

Of course, this also works when the delete() method of the object is called:

In [1]: from django.contrib.auth.models import User; from testapp.models import UserProfile; User.objects.all().delete(); UserProfile.objects.all().delete()

In [2]: user=User(username='foo'); user.save()

In [3]: profile=UserProfile(user=user); profile.save()

In [4]: profile.delete()

In [5]: User.objects.all()
Out[5]: []

Note that because of cascade delete, this works both ways:

In [1]: from django.contrib.auth.models import User; from testapp.models import UserProfile; User.objects.all().delete(); UserProfile.objects.all().delete()

In [2]: user=User(username='foo'); user.save()

In [3]: profile=UserProfile(user=user); profile.save()

In [4]: user.delete()

In [5]: User.objects.all()
Out[5]: []

In [6]: UserProfile.objects.all()
Out[6]: []

If you need to know more about signals, refer to Django’s extensive documentation.