clean django api in serilizer - django-rest-framework

Question

i write a django api i would like to know if reminder field changed then the Appointment model object save current user.
i used this link
See object changes in post_save in django rest framework
and write this code
class AppointmentBackOfficeViewSet(mixins.ListModelMixin,
mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.CreateModelMixin,
viewsets.GenericViewSet):
model = Appointment
read_serializer_class = AppointmentSerializer
write_serializer_class = AppointmentCreateSerializer
reminder_change = False
def perform_update(self, serializer):
if 'reminder' in serializer.validated_data:
self.reminder_change = True
serializer.save()
def update(self, request, *args, **kwargs):
super(AppointmentBackOfficeViewSet, self).update(request, *args, **kwargs)
instance = self.get_object()
instance.user = request.user
if self.reminder_change:
instance.reminder_user = request.user
instance.save()
res = self.write_serializer_class(instance).data
return Response(res)
class AppointmentCreateSerializer(serializers.ModelSerializer):
class Meta:
model = Appointment
exclude = ['created_time', 'modified_time']
is there a way to write this code clearer than this :
dont use self.reminder_change class field is there better way?
may be move this lines to serializer??(in serializer dont access to request.user)

Answer 1

Removed unecessary fields and update method:
class AppointmentBackOfficeViewSet(mixins.ListModelMixin,
mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.CreateModelMixin,
viewsets.GenericViewSet):
model = Appointment
read_serializer_class = AppointmentSerializer
write_serializer_class = AppointmentCreateSerializer
def perform_update(self, serializer):
# Here you can set attributes directly to the serializer update method
# It's like setting attribute directly to the updating model
# Check that reminder has been changed
reminder = serializer.validated_data.get('reminder')
if reminder and reminder != instance.reminder: # Reminder is different
serializer.save(user=self.request.user,
reminder_user=self.request.user)
else:
serializer.save(user=self.request.user)
This solution will work depending on what type of reminder field is.
If it's String or Integer it will be ok. Problem is that if it's object. Viewset will raise error because serializer reminder field would be integer but instance.reminder would be instance of the reminder object so keep this in mind.