from rest_framework.views import APIView
from rest_framework import parsers
from rest_framework import renderers
from rest_framework.response import Response
from rest_framework.authtoken.models import Token
from rest_framework.authtoken.serializers import AuthTokenSerializer


class ObtainAuthToken(APIView):
    throttle_classes = ()
    permission_classes = ()
    parser_classes = (parsers.FormParser, parsers.MultiPartParser, parsers.JSONParser,)
    renderer_classes = (renderers.JSONRenderer,)

    def post(self, request):
        serializer = AuthTokenSerializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        user = serializer.validated_data['user']
        token, created = Token.objects.get_or_create(user=user)
        return Response({'token': token.key})


obtain_auth_token = ObtainAuthToken.as_view()

from rest_framework.views import APIView
from rest_framework import parsers
from rest_framework import renderers
from rest_framework.response import Response
from rest_framework.authtoken.models import Token
from rest_framework.authtoken.serializers import AuthTokenSerializer


class ObtainAuthToken(APIView):
    throttle_classes = ()
    permission_classes = ()
    parser_classes = (parsers.FormParser, parsers.MultiPartParser, parsers.JSONParser,)
    renderer_classes = (renderers.JSONRenderer,)
    serializer_class = AuthTokenSerializer

    def post(self, request):
        serializer = self.serializer_class(data=request.data)
        serializer.is_valid(raise_exception=True)
        user = serializer.validated_data['user']
        token, created = Token.objects.get_or_create(user=user)
        return Response({'token': token.key})


obtain_auth_token = ObtainAuthToken.as_view()

Set serializer_class on ObtainAuthToken view
Set serializer_class on ObtainAuthToken view
