Django rest framework JWT and custom authentication backend

Question

I have a custom user model and have created a custom authentication backend. I am using django rest framework, and django rest framework JWT for token authentication.

User model:

class User(AbstractBaseUser, PermissionsMixin):
    email = models.EmailField(
        unique=True,
        max_length=254,
    )
    first_name = models.CharField(max_length=15)
    last_name = models.CharField(max_length=15)
    mobile = models.IntegerField(unique=True)
    date_joined = models.DateTimeField(default=timezone.now)
    is_active = models.BooleanField(default=True)
    is_admin = models.BooleanField(default=False)
    objects = UserManager()
    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['first_name', 'last_name', 'mobile']

Auth backend:

class EmailOrMobileAuthBackend(object):
    def authenticate(self, username=None, password=None):
        try:
            user = get_user_model().objects.get(email=username)
            if user.check_password(password):
                return user
        except User.DoesNotExist:
            if username.isdigit():
                try:
                    user = get_user_model().objects.get(mobile=username)
                    if user.check_password(password):
                        return user
                except User.DoesNotExist:
                    return None
            else:
                return None

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

And have added in the settings.py:

AUTHENTICATION_BACKENDS = ('accounts.email_mobile_auth_backend.EmailOrMobileAuthBackend',)

While to log in to django admin site, both the email and mobile number works fine in authenticating the user. However, when I try get the token for the user using django rest framework JWT, I get an error:

curl -X POST -d "[email protected]&password=123123" http://localhost/api-token-auth/

"non_field_errors": [
    "Unable to log in with provided credentials."
  ]

I have also added the custom auth backend class in the Default authentication for Rest framework, but its still not working:

REST_FRAMEWORK = {
    ...
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'accounts.email_mobile_auth_backend.EmailOrMobileAuthBackend',
        'rest_framework_jwt.authentication.JSONWebTokenAuthentication',
    ),
}

What am I missing? Why is it that its working while loggin to the django admin site, but get error when getting token with django rest framework jwt?

update

I have made another auth backend as advised and added it to the DEFAULT_AUTHENTICATION_CLASSES, but even this is not working.

class DrfAuthBackend(BaseAuthentication):
    def authenticate(self, username=None, password=None):
        try:
            user = get_user_model().objects.get(email=username)
            if user.check_password(password):
                return user, None
        except User.DoesNotExist:
            if username.isdigit():
                try:
                    user = get_user_model().objects.get(mobile=username)
                    if user.check_password(password):
                        return user, None
                except User.DoesNotExist:
                    return None
            else:
                return None

Settings:

REST_FRAMEWORK = {
    'DEFAULT_PERMISSION_CLASSES': (
        'rest_framework.permissions.IsAdminUser',
    ),
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'accounts.email_mobile_auth_backend.EmailOrMobileAuthBackend',
        'accounts.email_mobile_auth_backend.DrfAuthBackend',
        'rest_framework_jwt.authentication.JSONWebTokenAuthentication',
    ),
}

update

Changing the args in the auth class from username to email seems to work for obtaining auth_token but again its not working to log in to admin site.

class EmailOrMobileAuthBackend(object):
    def authenticate(self, email=None, password=None):
        try:
            user = get_user_model().objects.get(email=email)
            if user.check_password(password):
                return user
        except User.DoesNotExist:
            if email.isdigit():
                try:
                    user = get_user_model().objects.get(mobile=email)
                    if user.check_password(password):
                        return user
                except User.DoesNotExist:
                    return None
            else:
                return None

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

Answer 1

You should check the DRF documentation for custom authentication backends.

I think your custom authentication backend is breaking it, you may solve it by removing yours from DRF settings:

REST_FRAMEWORK = {
    ...
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'rest_framework_jwt.authentication.JSONWebTokenAuthentication',
    ),
}

Or by fixing yours which is basically not the same as for Django custom authentication, as you should extend from authentication.BaseAuthentication and it returns a tuple.

from rest_framework import authentication


class DrfAuthBackend(authentication.BaseAuthentication):
    def authenticate(self, email=None, password=None):
        try:
            user = get_user_model().objects.get(email=email)
            if user.check_password(password):
                return user, None
        except User.DoesNotExist:
            if email.isdigit():
                try:
                    user = get_user_model().objects.get(mobile=email)
                    if user.check_password(password):
                        return user, None
                except User.DoesNotExist:
                    return None
            else:
                return None

Then use that in the DRF settings:

REST_FRAMEWORK = {
    'DEFAULT_PERMISSION_CLASSES': (
        'rest_framework.permissions.IsAdminUser',
    ),
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'accounts.email_mobile_auth_backend.DrfAuthBackend',
        'rest_framework_jwt.authentication.JSONWebTokenAuthentication',
    ),
}

For the Django login:

class EmailOrMobileAuthBackend(object):
    def authenticate(self, username=None, password=None):
        try:
            user = get_user_model().objects.get(email=username)
            if user.check_password(password):
                return user
        except User.DoesNotExist:
            if username.isdigit():
                try:
                    user = get_user_model().objects.get(mobile=username)
                    if user.check_password(password):
                        return user
                except User.DoesNotExist:
                    return None
            else:
                return None

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

Then for the settings:

AUTHENTICATION_BACKENDS = ('accounts.email_mobile_auth_backend.EmailOrMobileAuthBackend',)