DRF create method in viewset or in serializer

Question

What is the difference between customizing the "create" method in DRF viewset or customizing it in the serializer? I understand the serializer is responsible to deserialize the data, i.e. the way the data is presented in the POST query; however, I can also create objects in related fields in the serializer.

#views.py
def create(self, request):
    pass

#serializer.py
def create(self, validated_data):
    return Model.objects.create(**validated_data)

When should I customize views/create vs. serializer/create?

Answer 1

create method from viewset

This method handles the POST request logic in the view, which by default does:

• instantiate the serializer with whatever data comes as payload in the request
• executed the is_valid method on the serializer
• perform the actual create by calling .save() method on serializer
• returns the view Response with serialized data and 201 status

You don't really need to override the create method on viewset, if is something that you need to send to the serializer from the view itself you can override perform_create which by default does serializer.save(). Eg. if you want to send the user from the request you can do:

    def perform_create(self, serializer):
        # here you will send `created_by` in the `validated_data` 
        serializer.save(created_by=self.request.user)

Note: Behind the scene save method will execute the create method on serializer with the validated_data

create method from serializer

This method just creates the actual model instance using the validated_data. You may override this method in case you need to create related objects, like the following:

   def create(self, validated_data):
        items_data = validated_data.pop('items')

        # similar to Parent.objects.create(**validated_data)
        parent = super().create(**validated_data)

        for item_data in items_data:
            Item.objects.create(parent=parent, **item_data)
        return parent

So here you are sending a payload with data regarding the Parent object but also a list of items with their representation, so now the create method will create also the Items and link them with the Parent instance.

To summarize this:

• in viewset the create method handles request-response flow
• in serializer the create method handles model instance creation using validated data.