Why my Django-Rest-Framework post method do not have the fields?

In the Django-Rest-Framework API, I can not use post for testing, I don't know why there is no the post fields.

My View:

class WHMCSPhysicalServerIPMIManagementAPIView(APIView):    serializer_class = WHMCSPhysicalServerIPMIManageSerializer    permission_classes = [IsAdminUser]    def post(self, request):"""        :param request:        action:        physical_server_name:        :return:"""        try:            physical_server_name = request.query_params.get('physical_server_name')            action = request.query_params.get('action')            if not physical_server_name or not action:                return Response(data="invalid request data", status=HTTP_400_BAD_REQUEST)            physical_server = PhysicalServer.objects.get(name=physical_server_name)            msg = ipmi_management_handler({'action': action, 'physical_server_id': physical_server.id})            return Response(data=msg, status=HTTP_200_OK)        except Exception as e:            return_data = "fail" if e.args == () else e.args[0]            return Response(data=return_data, status=HTTP_200_OK)

My serializers:

class WHMCSPhysicalServerIPMIManageSerializer(Serializer):    physical_server_name = serializers.IntegerField(write_only=True)      action = serializers.CharField(write_only=True)     whmcs_user_id = serializers.IntegerField(write_only=True)   

My url:

urlpatterns = [    url(r'^whmcs/physicalserver/ipmi_management/$', WHMCSPhysicalServerIPMIManagementAPIView.as_view(), name='whmcs-physicalserver-ipmi_management'),]