django authentication without a password - django

Question

I'm using the default authentication system with django, but I've added on an OpenID library, where I can authenticate users via OpenID. What I'd like to do is log them in, but it seems using the default django auth system, I need their password to authenticate the user. Is there a way to get around this without actually using their password?
I'd like to do something like this...
user = ... # queried the user based on the OpenID response
user = authenticate(user) # function actually requires a username and password
login(user)
I sooner just leave off the authenticate function, but it attaches a backend field, which is required by login.

Answer 1

It's straightforward to write a custom authentication backend for this. If you create yourapp/auth_backend.py with the following contents:
from django.contrib.auth.backends import ModelBackend
from django.contrib.auth.models import User
class PasswordlessAuthBackend(ModelBackend):
"""Log in to Django without providing a password.
"""
def authenticate(self, username=None):
try:
return User.objects.get(username=username)
except User.DoesNotExist:
return None
def get_user(self, user_id):
try:
return User.objects.get(pk=user_id)
except User.DoesNotExist:
return None
Then add to your settings.py:
AUTHENTICATION_BACKENDS = (
# ... your other backends
'yourapp.auth_backend.PasswordlessAuthBackend',
)
In your view, you can now call authenticate without a password:
user = authenticate(username=user.username)
login(request, user)

Answer 2

This is a bit of a hack but if you don't want to rewrite a bunch of stuff remove the authenticate
user.backend = 'django.contrib.auth.backends.ModelBackend'
login(request, user)
user would be your User object

Answer 3

In order to do authenticate without password, in your settings.py:
AUTHENTICATION_BACKENDS = [
# auth_backend.py implementing Class YourAuth inside yourapp folder
'yourapp.auth_backend.YourAuth',
# Default authentication of Django
'django.contrib.auth.backends.ModelBackend',
]
In your auth_backend.py:
NOTE: If you have custom model for your app then import from .models CustomUser
from .models import User
from django.conf import settings
# requires to define two functions authenticate and get_user
class YourAuth:
def authenticate(self, request, username=None):
try:
user = User.objects.get(username=username)
return user
except User.DoesNotExist:
return None
def get_user(self, user_id):
try:
return User.objects.get(pk=user_id)
except User.DoesNotExist:
return None
In your Views for custom login request:
# Your Logic to login user
userName = authenticate(request, username=uid)
login(request, userName)
For further reference, use the django documentation here.

Answer 4

You can easily fix this by creating your own authentication backend and adding it to the AUTHENTICATION_BACKENDS setting.
There are some OpenID backends available already, so with a bit of searching you could save yourself the trouble of writing one.