SchemaGenerator fails with message "object has no attribute 'get_serializer_class'"

[geekashu]

Hi,

I just upgraded to 3.4.0 of django-rest-framework. In my application i have a API view which doesn't have a GET method implemented only POST is there.

Now i am trying to auto generate the schema using the tutorial given. Here is my code for the schema view.

from rest_framework.decorators import api_view, renderer_classes
from rest_framework import renderers, schemas

@api_view()
@renderer_classes([renderers.CoreJSONRenderer, ])
def schema_view(request):
    generator = schemas.SchemaGenerator(title='Bookings API')
    return generator.get_schema()

Now when i try to view this schema i am getting this error.

Traceback (most recent call last):
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/django/core/handlers/base.py", line 149, in get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/django/core/handlers/base.py", line 147, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/django/views/generic/base.py", line 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/rest_framework/views.py", line 466, in dispatch
    response = self.handle_exception(exc)
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/rest_framework/views.py", line 463, in dispatch
    response = handler(request, *args, **kwargs)
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/rest_framework/decorators.py", line 52, in handler
    return func(*args, **kwargs)
  File "/home/ashish/Projects/backend/oyster/config/swagger.py", line 7, in schema_view
    generator = schemas.SchemaGenerator(title='Bookings API')
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/rest_framework/schemas.py", line 74, in __init__
    self.endpoints = self.get_api_endpoints(patterns)
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/rest_framework/schemas.py", line 128, in get_api_endpoints
    prefix=path_regex
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/rest_framework/schemas.py", line 121, in get_api_endpoints
    link = self.get_link(path, method, callback)
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/rest_framework/schemas.py", line 196, in get_link
    fields += self.get_serializer_fields(path, method, callback, view)
  File "/home/ashish/Env/backend/lib/python3.4/site-packages/rest_framework/schemas.py", line 256, in get_serializer_fields
    serializer_class = view.get_serializer_class()
AttributeError: 'LogoutView' object has no attribute 'get_serializer_class'

Here is my LogoutView class..

class LogoutView(APIView):
    permission_classes = (AllowAny,)

    def post(self, request):
        return self.logout(request)

    def logout(self, request):
        try:
            request.user.auth_token.delete()
        except (AttributeError, ObjectDoesNotExist):
            pass

        logout(request)

        log.info('Logout Successful | %s' % request.user)
        content = {'success': settings.USERS_LOGOUT_MSG}
        return Response(content, status=status.HTTP_200_OK)

Am i missing something? What needs to be done to auto generate the schema?

[decentral1se]

I am also seeing a similar error. Except, that the call to view.get_serializer_class from my ModelViewSet gets into the get_serializer_class method and fails when it doesn't have the request attribute.

Is there any update on this one? I will try to write a failing test case ...

@geekashu

Have you defined a serializer for this view? You should either have a serializer_class = X or override get_serializer_class() ?

[xordoquy]

The OP mentions an APIView and I'm not sure SchemaGenerator do work with them which is why I removed the bug status.

@lwm test case would definitively help get this fixed faster.

[geekashu]

@lwm No i haven't defined a serializer for this view.

@xordoquy SchemaGenerator should work with all APIView as per this comment

[MadWombat]

I am getting the same error on my function based views. My view looks sort of like this

@api_view(['GET', 'POST'])
@authentication_classes((CustomAuthentication, ))
@permission_classes((CustomPermission, ))
def get_all(request):
    return Response(CustomSerializer(CustomModel.objects.all(), many=True).data)

Before you ask, I have to support both GET and POST for legacy reasons.

[sasha0]

Issue is easy to re-recreate - basically when SchemaGenerator iterates through API views and any of them derived from APIView, simply because it does not have this method.

[sasha0]

I've added PR with the test and suggested fix.

[xordoquy]

Thanks, this will definitively help

[swehba]

Not sure why this issue was closed. I also have this problem, and it appears that it occurs for any view that implements get_serializer_class if, within that method, you access self.request (e.g., if self.request.method == 'GET':...). In that situation, self.request is set to None.

[Ambitiont109]

I also have the same issue with Django 4.0 & Django Rest Framework 3.13.1

  File "/.../views.py", line 49, in get_serializer_class
    if self.request.method == 'GET':
AttributeError: 'NoneType' object has no attribute 'method'