Return different serializer after create() in CreateAPIView in Django REST Framework

Question

I'm using Django 2.2 and Django REST Framework.

I have to serializers for the same model.

class OrderListSerializer(serializers.ModelSerializer):
    plan = PlanBaseSerializer(read_only=True, many=False)

    class Meta:
        model = Order
        fields = [
            'id', 'name', 'plan', 'pricing',
            'created', 'completed',
        ]


class OrderCreateSerializer(serializers.ModelSerializer):
    plan_pricing = serializers.IntegerField(required=True, write_only=True)

    class Meta:
        model = Order
        fields = [
            'plan_pricing'
        ]

    def create(self, validated_data):
        plan_pricing_ = validated_data.pop('plan_pricing', None)
        try:
            plan_pricing = PlanPricing.objects.get(pk=plan_pricing_)
        except PlanPricing.DoesNotExists:
            raise ValidationError('Plan pricing not available')

        validated_data['plan'] = plan_pricing.plan
        validated_data['amount'] = plan_pricing.price

        return super().create(validated_data)

OrderListSerializer serializer is used for listing orders or order detail view and OrderCreateSerializer is used for creating a new order instance.

The view is

class CreateOrderView(generics.CreateAPIView):
    serializer_class = OrderCreateSerializer

    def perform_create(self, serializer):
        serializer.save(user=self.request.user)

This is working fine as the order object is creating as expected. But the returned value contains no data.

I want to use OrderListSerializer to render saved order details after creating the order.

How to change the serializer class after creating the object?

Also, I have to trigger a signal after the object has been successfully created. What is the best place to trigger a signal?

Answer 1

Change CreateOrderView as below,

class CreateOrderView(generics.CreateAPIView):
    serializer_class = OrderCreateSerializer

    def perform_create(self, serializer):
        return serializer.save(user=self.request.user)

    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        instance = self.perform_create(serializer)
        instance_serializer = OrderListSerializer(instance)
        return Response(instance_serializer.data)

serializer.save() returns the instance that just created or updated. So we use that istance to pass to the OrderListSerializer and returning the corresponding response.