Django Swagger starts failing when include is used in django urls - django

Question

I am using django rest_framework_swagger for my django project, everything was working fine but when I added some URLs with include method Swagger start giving me 500 internal server error.
I am not sure why this error is coming, I have checked but didn't find anything to fix this error.
I am using:
django 1.11.7
rest_framework_swagger 2.1.2
django rest framework 3.7.3
URLs
from django.conf.urls import url, include
from link_one.views import LinkOneViewSet
from link_two.views import LinkTwoViewSet
schema_view = get_swagger_view(title='My Project APIs')
urlpatterns = [
url(r'^$', schema_view),
url(r'^foo/(?P<foo_id>\w+)/bar/(?P<bar_id>\w+)/link1',
LinkOneViewSet.as_view({'get': 'list'})),
url(r'^foo/(?P<foo_id>\w+)/bar/(?P<bar_id>\w+)/link2',
LinkTwoViewSet.as_view({'get': 'list'})),
url(r'^foo/(?P<foo_id>\w+)/bar/(?P<bar_id>\w+)/link3',
include('link_three.urls'))
]+ static(settings.STATIC_URL, document_root=settings.STATIC_ROOT)
Error
[25/Jan/2021 14:03:31] ERROR [django.request.exception:135] Internal Server Error: /
Traceback (most recent call last):
File "C:\Users\myuser\conda_env\lib\site-packages\django\core\handlers\exception.py", line 41, in inner
response = get_response(request)
File "C:\Users\myuser\conda_env\lib\site-packages\django\core\handlers\base.py", line 187, in _get_response
response = self.process_exception_by_middleware(e, request)
File "C:\Users\myuser\conda_env\lib\site-packages\django\core\handlers\base.py", line 185, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Users\myuser\conda_env\lib\site-packages\django\views\decorators\csrf.py", line 58, in wrapped_view
return view_func(*args, **kwargs)
File "C:\Users\myuser\conda_env\lib\site-packages\django\views\generic\base.py", line 68, in view
return self.dispatch(request, *args, **kwargs)
File "C:\Users\myuser\conda_env\lib\site-packages\rest_framework\views.py", line 489, in dispatch
response = self.handle_exception(exc)
File "C:\Users\myuser\conda_env\lib\site-packages\rest_framework\views.py", line 449, in handle_exception
self.raise_uncaught_exception(exc)
File "C:\Users\myuser\conda_env\lib\site-packages\rest_framework\views.py", line 486, in dispatch
response = handler(request, *args, **kwargs)
File "C:\Users\myuser\conda_env\lib\site-packages\rest_framework_swagger\views.py", line 32, in get
schema = generator.get_schema(request=request)
File "C:\Users\myuser\conda_env\lib\site-packages\rest_framework\schemas\generators.py", line 278, in get_schema
links = self.get_links(None if public else request)
File "C:\Users\myuser\conda_env\lib\site-packages\rest_framework\schemas\generators.py", line 316, in get_links
link = view.schema.get_link(path, method, base_url=self.url)
File "C:\Users\myuser\conda_env\lib\site-packages\rest_framework\schemas\inspectors.py", line 179, in get_link
fields += self.get_serializer_fields(path, method)
File "C:\Users\myuser\conda_env\lib\site-packages\rest_framework\schemas\inspectors.py", line 302, in get_serializer_fields
serializer = view.get_serializer()
File "C:\Users\myuser\conda_env\lib\site-packages\rest_framework\generics.py", line 112, in get_serializer
return serializer_class(*args, **kwargs)
TypeError: 'list' object is not callable

Answer 1

After searching a lot and debugging, I have found a solution for this.
The solution is, don't use multiple serializer classes for a ViewSet.
In my one viewset I was doing this and this is what creating the problem.
class FooBarViewset(ModelViewSet):
serializer_class = [DefaultSerializer, BarSerializer, FooSerializer]
But I did not realize that this will cause the error.
Here is Fix that I am using
class FooBarViewset(ModelViewSet):
serializer_class = DefaultSerializer
You can also use the get_serializer method and map serializer class with an action, please check this answer Django rest framework, use different serializers in the same ModelViewSet