Login with username or email in Django.

we covered many things in django auth app but what if we want
to login with email instead of username ? or both?.

It's very easy to override the authenticate function to login with email or username.

if you didn't read django auth posts you can have a look at them part 1 , part 2 , part 3 , part 4 .

First we will create new file inside our users app called
backends.py, and we will extend the Django ModelBackend and override authenticate function.

# users/backends.py

from django.contrib.auth.backends import ModelBackend
from django.contrib.auth import get_user_model
from django.db.models import Q


UserModel = get_user_model()


class EmailBackend(ModelBackend):
    def authenticate(self, request, username=None, password=None, **kwargs):
        try:
            user = UserModel.objects.get(
                Q(username__iexact=username) | Q(email__iexact=username)
            )
        except UserModel.DoesNotExist:
            # Run the default password hasher once to reduce the timing
            # difference between an existing and a nonexistent user (#20760).
            UserModel().set_password(password)
        else:
            if user.check_password(password) and self.user_can_authenticate(user):
                return user

I didn't came up with that code I took it from the django source code at django/contrib/auth/backends.py and just edited the query of checking the user credentials to check with email or username.

Now we need to use this in settings.py.

# settings.py
AUTHENTICATION_BACKENDS = ['users.backends.EmailBackend']

And that's it user can login with either username or email.

If you followed up with our previous posts you will see that we created a custom login form, so we will have to edit it too.

# users/forms.py
...
...

from django.db.models import Q # New

class CustomLoginForm(AuthenticationForm):
    username = forms.CharField(
        widget=forms.TextInput(attrs={"placeholder": "User Name Or Email"})
    )
    password = forms.CharField(
        label="Password",
        widget=forms.PasswordInput(attrs={"placeholder": "Password"}),
    )

    def clean(self):
        username = self.cleaned_data.get("username")
        password = self.cleaned_data.get("password")

        if username is not None and password:
            self.user_cache = authenticate(
                self.request, username=username, password=password
            )
            if self.user_cache is None:
                try:
                    user = User.objects.get(
                        Q(username__iexact=username) | Q(email__iexact=username) # New
                    )
                except User.DoesNotExist:
                    user = None
                if user is not None:
                    if not user.is_active:
                        self.confirm_login_allowed(user)
                    else:
                        raise self.get_invalid_login_error()
                else:
                    raise self.get_invalid_login_error()
            else:
                self.confirm_login_allowed(self.user_cache)

        return self.cleaned_data

    def confirm_login_allowed(self, user):
        if not user.is_active:
            error = "The account is closed, please contact us for more details."
            raise forms.ValidationError(error)

# users/forms.py
...
...

class RegisterForm(UserCreationForm):
    def clean_email(self):
        email = self.cleaned_data["email"]
        if email:
            match = User.objects.filter(email=email)
            if match:
                raise forms.ValidationError("This email address is already in use")
            return email

    def __init__(self, *args, **kwargs): # New
        super(RegisterForm, self).__init__(*args, **kwargs)
        self.fields["email"].required = True

    class Meta:
        model = User
        fields = ("username", "first_name", "last_name", "email")

We have clean_email function to check if email exists first, you can read Check User's Email Existence for more information.

And we are done!

I hope the tutorial was simple.
Feel free to reach out if you have any questions.

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