Set default value to UserProfile model field from User instance field

Question

I use UserProfile model for keeping additional info about user and one of the fields is subdomain variable that is by default should be set to username. Here is UserProfile model:

class UserProfile(models.Model):
    theme = models.ForeignKey(Theme, unique=True, null=True)
    user = models.ForeignKey(User, unique=True)
    subdomain = models.CharField(default=self.user.username, max_length=30)

I implemented Django signals feature to create UserProfile model instance automatically on user creation. Now I need to set subdomain variable to username. How can I do this?

Answer 1

Since you are automatically creating an UserProfile using a signal you can explicitly set the User instance's username as the UserProfile subdomain. For e.g.

def create_user_profile(sender, instance, **kwargs):
    profile = UserProfile(user = instance, subdomain = instance.username, ...)
    profile.save()

Another way to do this would be to override the save() method such that if no subdomain is supplied you can set it to user.username.