DRF How to perform additional operations on an instance - django

Question

Which of the given ways of writing additional logic is technically correct? The example includes changing the status of the document. After a quick reserach of similar questions, I understand that there are 3 possibilities described below. However, no answer describes which solution is used during daily practicals, and the examples from the documentation do not dispel doubts. Please help.
Providing custom data to the serializer and the standard model serializer:
class PZSaveAPIView(APIView):
#transaction.atomic
def patch(self, request, pk, format=None):
document = get_object_or_404(PZ, pk=pk)
print(request.data)
serializer = PZModelSerializer(
document, data={'status': 'E'}, partial=True)
if serializer.is_valid():
serializer.save()
return Response(serializer.data)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
After the object is serialized, change the status:
class PZSaveAPIView(APIView):
#transaction.atomic
def patch(self, request, pk, format=None):
document = get_object_or_404(PZ, pk=pk)
serializer = PZModelSerializer(
document, data=request.data, partial=True)
if serializer.is_valid():
pz = serializer.save()
pz.status = 'S'
pz.save()
return Response(serializer.data)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
Contain the logic in the serializer, and the view stays basic:
class PZUpdateSerializer(serializers.ModelSerializer):
class Meta:
model = PZ
fields = '__all__'
def update(self, instance, validated_data):
instance.status = 'S'
instance.save()
return instance
Is it even necessary to use a serializer in such cases? Example:
class PZSaveAPIView(APIView):
def patch(self, pk):
document = get_object_or_404(PZ, pk=pk)
document.set_status_saved()
document.save()
return Response('Document saved')

Answer 1

If there is a need to validate data and return those data to the front end, the serializer is definitely required. So, whether to use a serializer or not depends upon the case, it's okay not to use a serializer if it is not in need.
And about whether to put logic on views or serializer, Django books recommend thick serializer and thin views. And Django rest framework itself provides update and create methods in ModelSerializer which mean it prefers the logic to update and create inside serializer and views to just return response.