[FIXED] WrappedAttributeError 'IsAdminUser' object has no attribute 'authenticate'

Issue

I'm using Django Rest Framework with permission_classes to create an API. My understanding is that once I go to that API with an unauthenticated user I should be redirected to the login form, right? Instead, I get the following error:

WrappedAttributeError at /sessions/api/listPatients/ 'IsAdminUser' object has no attribute 'authenticate'

There's no redirect to the login form... and I don't understand why.

Why is this happening? What am I doing wrong? How to fix that?

Here's the urls.py:

path('api/getSessions/',
     views.GetSessions.as_view(),
     name="GetSessionsAPI"),

And here's the view that I'm trying to go to:

class GetSessions(generics.ListCreateAPIView):
    permission_classes = (permissions.IsAuthenticated,)
    serializer_class = SessionSerializer

    def get_queryset(self):
        if self.request.user.is_authenticated:
            return Session.objects.filter(
                patient__created_by_user=self.request.user)
        else:
            raise PermissionDenied

and here's the other one raising the error:

class ListPatients(generics.ListAPIView):

    permission_classes = (permissions.IsAuthenticated,)
    serializer_class = PatientsSerializer

    def get_queryset(self):
        if self.request.user.is_authenticated:
            try:
                return Patient.objects.filter(
                    created_by_user=self.request.user).\
                   filter(curently_active=True)
            except Patient.DoesNotExist:
                raise PermissionDenied
    else:
        raise PermissionDenied

Here's the full traceback:

WrappedAttributeError at /sessions/api/listPatients/
'IsAdminUser' object has no attribute 'authenticate'
Request Method: GET
Request URL:    http://localhost:8000/sessions/api/listPatients/
Django Version: 2.0.5
Exception Type: WrappedAttributeError
Exception Value:    
'IsAdminUser' object has no attribute 'authenticate'
Exception Location: /Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/request.py in _authenticate, line 375
Python Executable:  /Users/karol/Development/ZS_2_0/ZS_2_0_venv/bin/python
Python Version: 3.6.4
Python Path:    
['/Users/karol/Development/ZS_2_0/zapiszsesje_2_0',
 '/Users/karol/Development/ZS_2_0',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/patient',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/services',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/notes',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/practice',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/activity_logger',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/session',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/my_calendar',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/session/tests',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/zapiszsesje_2_0/users',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/zapiszsesje_2_0',
 '/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python36.zip',
 '/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6',
 '/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/lib-dynload',
 '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6',
 '/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages',
 '/Applications/PyCharm.app/Contents/helpers/pycharm_matplotlib_backend',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/zapiszsesje_2_0',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0',
 '/Users/karol/Development/ZS_2_0/zapiszsesje_2_0/zapiszsesje_2_0']
Server time:    Sat, 17 Nov 2018 15:29:56 +0100
Traceback Switch to copy-and-paste view

/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/request.py in wrap_attributeerrors
        yield ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/request.py in user
                self._authenticate() ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/request.py in _authenticate
                user_auth_tuple = authenticator.authenticate(self) ...
▶ Local vars
During handling of the above exception ('IsAdminUser' object has no attribute 'authenticate'), another exception occurred:
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/django/core/handlers/exception.py in inner
            response = get_response(request) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/django/core/handlers/base.py in _get_response
                response = self.process_exception_by_middleware(e, request) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/django/core/handlers/base.py in _get_response
                response = wrapped_callback(request, *callback_args, **callback_kwargs) ...
▶ Local vars
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/contextlib.py in inner
                return func(*args, **kwds) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/django/views/decorators/csrf.py in wrapped_view
        return view_func(*args, **kwargs) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/django/views/generic/base.py in view
            return self.dispatch(request, *args, **kwargs) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/views.py in dispatch
            response = self.handle_exception(exc) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/views.py in handle_exception
            self.raise_uncaught_exception(exc) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/views.py in dispatch
            self.initial(request, *args, **kwargs) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/views.py in initial
        self.perform_authentication(request) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/views.py in perform_authentication
        request.user ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/request.py in user
                self._authenticate() ...
▶ Local vars
/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/contextlib.py in __exit__
                self.gen.throw(type, value, traceback) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/request.py in wrap_attributeerrors
        six.reraise(type(exc), exc, info[2]) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/django/utils/six.py in reraise
            raise value.with_traceback(tb) ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/request.py in wrap_attributeerrors
        yield ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/request.py in user
                self._authenticate() ...
▶ Local vars
/Users/karol/Development/ZS_2_0/ZS_2_0_venv/lib/python3.6/site-packages/rest_framework/request.py in _authenticate
                user_auth_tuple = authenticator.authenticate(self) ...
▶ Local vars

UPDATE: This error goes away when I change the following line in my base.py settings file:

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES': (
        'rest_framework.authentication.BasicAuthentication',
        'rest_framework.authentication.SessionAuthentication',
        'rest_framework.permissions.IsAdminUser', # <- commenting out solves the problem!
    ),

However, the line has been added following the book Two Scoops of Django ...

Solution

Turned out it was my mistake which got uncovered thanks to the comments under my question:

By mistake I have added 'rest_framework.permissions.IsAdminUser', to DEFAULT_AUTHENTICATION_CLASSES instead of DEFAULT_PERMISSION_CLASSES inside my settings file.

That solved the problem - thanks! :)

Answered By - user1544500