Django - Login with Email

If you’re starting a new project, django highly recommended you to set up a custom user model. (see https://docs.djangoproject.com/en/dev/topics/auth/customizing/#using-a-custom-user-model-when-starting-a-project)

and if you did it, add three lines to your user model:

class MyUser(AbstractUser):
    USERNAME_FIELD = 'email'
    email = models.EmailField(_('email address'), unique=True) # changes email to unique and blank to false
    REQUIRED_FIELDS = [] # removes email from REQUIRED_FIELDS

Then authenticate(email=email, password=password) works, while authenticate(username=username, password=password) stops working.

You should write a custom authentication backend. Something like this will work:

from django.contrib.auth import get_user_model
from django.contrib.auth.backends import ModelBackend

class EmailBackend(ModelBackend):
    def authenticate(self, request, username=None, password=None, **kwargs):
        UserModel = get_user_model()
        try:
            user = UserModel.objects.get(email=username)
        except UserModel.DoesNotExist:
            return None
        else:
            if user.check_password(password):
                return user
        return None

Then, set that backend as your auth backend in your settings:

AUTHENTICATION_BACKENDS = ['path.to.auth.module.EmailBackend']

Updated. Inherit from ModelBackend as it implements methods like get_user() already.

See docs here: https://docs.djangoproject.com/en/3.0/topics/auth/customizing/#writing-an-authentication-backend

Email authentication for Django 3.x

For using email/username and password for authentication instead of the default username and password authentication, we need to override two methods of ModelBackend class: authenticate() and get_user():

The get_user method takes a user_id – which could be a username, database ID or whatever, but has to be unique to your user object – and returns a user object or None. If you have not kept email as a unique key, you will have to take care of multiple result returned for the query_set. In the below code, this has been taken care of by returning the first user from the returned list.

from django.contrib.auth.backends import ModelBackend, UserModel
from django.db.models import Q

class EmailBackend(ModelBackend):
    def authenticate(self, request, username=None, password=None, **kwargs):
        try: #to allow authentication through phone number or any other field, modify the below statement
            user = UserModel.objects.get(Q(username__iexact=username) | Q(email__iexact=username))
        except UserModel.DoesNotExist:
            UserModel().set_password(password)
        except MultipleObjectsReturned:
            return User.objects.filter(email=username).order_by('id').first()
        else:
            if user.check_password(password) and self.user_can_authenticate(user):
                return user

    def get_user(self, user_id):
        try:
            user = UserModel.objects.get(pk=user_id)
        except UserModel.DoesNotExist:
            return None

        return user if self.user_can_authenticate(user) else None

By default, AUTHENTICATION_BACKENDS is set to:

['django.contrib.auth.backends.ModelBackend']

In settings.py file, add following at the bottom to override the default:

AUTHENTICATION_BACKENDS = ('appname.filename.EmailBackend',)