solve #9598

Author: NikitaJaiswal77

docs/api-guide/authentication.md

@@ -34,6 +34,17 @@ The authentication schemes are always defined as a list of classes.  REST framew
 If no class authenticates, `request.user` will be set to an instance of `django.contrib.auth.models.AnonymousUser`, and `request.auth` will be set to `None`.
 
 The value of `request.user` and `request.auth` for unauthenticated requests can be modified using the `UNAUTHENTICATED_USER` and `UNAUTHENTICATED_TOKEN` settings.
+### MultiUserModelAuthentication
+The `MultiUserModelAuthentication` class supports authentication for multiple user models. 
+
+To use this authentication mechanism, add it to your `DEFAULT_AUTHENTICATION_CLASSES` in `settings.py`:
+
+```python
+REST_FRAMEWORK = {
+    'DEFAULT_AUTHENTICATION_CLASSES': [
+        'rest_framework.authentication.MultiUserModelAuthentication',
+    ],
+}
 
 ## Setting the authentication scheme
 

rest_framework/authentication.py

@@ -230,3 +230,63 @@ def authenticate(self, request):
         user = authenticate(request=request, remote_user=request.META.get(self.header))
         if user and user.is_active:
             return (user, None)
+class MultiUserModelAuthentication(BaseAuthentication):
+    """
+    Custom authentication to support multiple user models.
+    """
+
+    def authenticate(self, request):
+        """
+        Authenticate the request for multiple user models.
+        Returns a tuple of (user, None) or raises an exception if authentication fails.
+        """
+        auth = get_authorization_header(request).split()
+
+        if not auth or auth[0].lower() != b'basic':
+            return None
+
+        if len(auth) == 1:
+            msg = _('Invalid basic header. No credentials provided.')
+            raise exceptions.AuthenticationFailed(msg)
+        elif len(auth) > 2:
+            msg = _('Invalid basic header. Credentials string should not contain spaces.')
+            raise exceptions.AuthenticationFailed(msg)
+
+        try:
+            try:
+                auth_decoded = base64.b64decode(auth[1]).decode('utf-8')
+            except UnicodeDecodeError:
+                auth_decoded = base64.b64decode(auth[1]).decode('latin-1')
+
+            userid, password = auth_decoded.split(':', 1)
+        except (TypeError, ValueError, UnicodeDecodeError, binascii.Error):
+            msg = _('Invalid basic header. Credentials not correctly base64 encoded.')
+            raise exceptions.AuthenticationFailed(msg)
+
+        return self.authenticate_credentials(userid, password, request)
+
+    def authenticate_credentials(self, userid, password, request=None):
+        """
+        Authenticate credentials for multiple user models.
+        """
+        # List of user models to authenticate against
+        user_models = ['users.User', 'admins.AdminUser']
+
+        for model_name in user_models:
+            try:
+                UserModel = get_user_model()  # Replace with custom logic for each model
+                credentials = {UserModel.USERNAME_FIELD: userid, 'password': password}
+                user = authenticate(request=request, **credentials)
+                
+                if user:
+                    if not user.is_active:
+                        raise exceptions.AuthenticationFailed(_('User inactive or deleted.'))
+                    return (user, None)
+            except Exception as e:
+                # Continue to next user model if the current one fails
+                continue
+
+        raise exceptions.AuthenticationFailed(_('Invalid username/password for all user models.'))
+
+    def authenticate_header(self, request):
+        return 'Basic realm="api"'

rest_framework/settings.py

@@ -37,7 +37,8 @@
         'rest_framework.parsers.FormParser',
         'rest_framework.parsers.MultiPartParser'
     ],
-    'DEFAULT_AUTHENTICATION_CLASSES': [
+    'DEFAULT_AUTHENTICATION_CLASSES': [        
+        'rest_framework.authentication.MultiUserModelAuthentication',
         'rest_framework.authentication.SessionAuthentication',
         'rest_framework.authentication.BasicAuthentication'
     ],

tests/authentication/test_authentication.py

@@ -6,7 +6,10 @@
 from django.http import HttpResponse
 from django.test import TestCase, override_settings
 from django.urls import include, path
-
+from rest_framework.test import APIClient
+from django.test import TestCase
+from users.models import User
+from admins.models import AdminUser
 from rest_framework import (
     HTTP_HEADER_ENCODING, exceptions, permissions, renderers, status
 )
@@ -597,3 +600,20 @@ def test_remote_user_works(self):
         response = self.client.post('/remote-user/',
                                     REMOTE_USER=self.username)
         self.assertEqual(response.status_code, status.HTTP_200_OK)
+class MultiUserModelAuthenticationTest(TestCase):
+    def setUp(self):
+        self.client = APIClient()
+        self.user = User.objects.create_user(username='user', password='userpass')
+        self.admin = AdminUser.objects.create_user(username='admin', password='adminpass')
+
+    def test_user_authentication(self):
+        response = self.client.post('/api/token/', {'username': 'user', 'password': 'userpass'})
+        self.assertEqual(response.status_code, 200)
+
+    def test_admin_authentication(self):
+        response = self.client.post('/api/token/', {'username': 'admin', 'password': 'adminpass'})
+        self.assertEqual(response.status_code, 200)
+
+    def test_invalid_authentication(self):
+        response = self.client.post('/api/token/', {'username': 'invalid', 'password': 'invalid'})
+        self.assertEqual(response.status_code, 401)