Extending the User model with custom fields in Django

Well, some time passed since 2008 and it's time for some fresh answer. Since Django 1.5 you will be able to create custom User class. Actually, at the time I'm writing this, it's already merged into master, so you can try it out.

There's some information about it in docs or if you want to dig deeper into it, in this commit.

All you have to do is add AUTH_USER_MODEL to settings with path to custom user class, which extends either AbstractBaseUser (more customizable version) or AbstractUser (more or less old User class you can extend).

For people that are lazy to click, here's code example (taken from docs):

from django.db import models
from django.contrib.auth.models import (
    BaseUserManager, AbstractBaseUser
)


class MyUserManager(BaseUserManager):
    def create_user(self, email, date_of_birth, password=None):
        """
        Creates and saves a User with the given email, date of
        birth and password.
        """
        if not email:
            raise ValueError('Users must have an email address')

        user = self.model(
            email=MyUserManager.normalize_email(email),
            date_of_birth=date_of_birth,
        )

        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_superuser(self, username, date_of_birth, password):
        """
        Creates and saves a superuser with the given email, date of
        birth and password.
        """
        u = self.create_user(username,
                        password=password,
                        date_of_birth=date_of_birth
                    )
        u.is_admin = True
        u.save(using=self._db)
        return u


class MyUser(AbstractBaseUser):
    email = models.EmailField(
                        verbose_name='email address',
                        max_length=255,
                        unique=True,
                    )
    date_of_birth = models.DateField()
    is_active = models.BooleanField(default=True)
    is_admin = models.BooleanField(default=False)

    objects = MyUserManager()

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['date_of_birth']

    def get_full_name(self):
        # The user is identified by their email address
        return self.email

    def get_short_name(self):
        # The user is identified by their email address
        return self.email

    def __unicode__(self):
        return self.email

    def has_perm(self, perm, obj=None):
        "Does the user have a specific permission?"
        # Simplest possible answer: Yes, always
        return True

    def has_module_perms(self, app_label):
        "Does the user have permissions to view the app `app_label`?"
        # Simplest possible answer: Yes, always
        return True

    @property
    def is_staff(self):
        "Is the user a member of staff?"
        # Simplest possible answer: All admins are staff
        return self.is_admin

The least painful and indeed Django-recommended way of doing this is through a OneToOneField(User) property.

Extending the existing User model

…

If you wish to store information related to User, you can use a one-to-one relationship to a model containing the fields for additional information. This one-to-one model is often called a profile model, as it might store non-auth related information about a site user.

That said, extending django.contrib.auth.models.User and supplanting it also works...

Substituting a custom User model

Some kinds of projects may have authentication requirements for which Django’s built-in User model is not always appropriate. For instance, on some sites it makes more sense to use an email address as your identification token instead of a username.

[Ed: Two warnings and a notification follow, mentioning that this is pretty drastic.]

I would definitely stay away from changing the actual User class in your Django source tree and/or copying and altering the auth module.

Since Django 1.5 you may easily extend the user model and keep a single table on the database.

from django.contrib.auth.models import AbstractUser
from django.db import models
from django.utils.translation import ugettext_lazy as _

class UserProfile(AbstractUser):
    age = models.PositiveIntegerField(_("age"))

You must also configure it as current user class in your settings file

# supposing you put it in apps/profiles/models.py
AUTH_USER_MODEL = "profiles.UserProfile"

If you want to add a lot of users' preferences the OneToOneField option may be a better choice thought.

A note for people developing third party libraries: if you need to access the user class remember that people can change it. Use the official helper to get the right class

from django.contrib.auth import get_user_model

User = get_user_model()

Note: this answer is deprecated. see other answers if you are using Django 1.7 or later.

This is how I do it.

#in models.py
from django.contrib.auth.models import User
from django.db.models.signals import post_save

class UserProfile(models.Model):  
    user = models.OneToOneField(User)  
    #other fields here

    def __str__(self):  
          return "%s's profile" % self.user  

def create_user_profile(sender, instance, created, **kwargs):  
    if created:  
       profile, created = UserProfile.objects.get_or_create(user=instance)  

post_save.connect(create_user_profile, sender=User) 

#in settings.py
AUTH_PROFILE_MODULE = 'YOURAPP.UserProfile'

This will create a userprofile each time a user is saved if it is created. You can then use

  user.get_profile().whatever

Here is some more info from the docs

http://docs.djangoproject.com/en/dev/topics/auth/#storing-additional-information-about-users

Update: Please note that AUTH_PROFILE_MODULE is deprecated since v1.5: https://docs.djangoproject.com/en/1.5/ref/settings/#auth-profile-module