Django Rest Framework - create objects passed as a list attribute of nested object

Question

Xzibit jokes aside, here's my model: ``` from django.db import models class ProjectProfitAndLoss(models.Model): pass class Component(models.Model): profit_and_loss = models.ForeignKey(ProjectProfitAndLoss, related_name='components') name = models.CharField(max_length=250) class ComponentProductionVolume(models.Model): component = models.ForeignKey(Component, related_name='volumes') offset = models.IntegerField() volume = models.DecimalField(max_digits=16, decimal_places=4) ``` Serializers: ``` from rest_framework import serializers class ComponentProductionVolumeSerializer(serializers.ModelSerializer): class Meta: model = ComponentProductionVolume class ComponentSerializer(serializers.ModelSerializer): volumes = ComponentProductionVolumeSerializer(many=True, allow_add_remove=True) class Meta: model = Component class ProjectProfitAndLossSerializer(serializers.ModelSerializer): components = ComponentSerializer(many=True, allow_add_remove=True) class Meta: model = ProjectProfitAndLoss ``…

Accepted Answer

DRF currently (version 2.3.13) has no built-in functionality to create nested relations. However, it is quite straight-forward to accomplish this by overriding `create` in a `ListCreateView`:

```
class ComponentList(generics.ListCreateAPIView):
    model = Component
    serializer_class = ComponentSerializer

def create(self, request, *args, **kwargs):
        data = request.DATA

# note transaction.atomic was introduced in Django 1.6
            with transaction.atomic():
                component = Component(
                    profit_and_loss=data['component_comments'],
                    name=data['name']
                )
                component.clean()
                component.save()

for volume in data['volumes']:
                    ComponentProductionVolume.objects.create(
                        component=component,
                        offset=volume['offset'],
                        volume=volume['volume']
                    )

serializer = ComponentSerializer(component)
        headers = self.get_success_headers(serializer.data)

return Response(serializer.data, status=status.HTTP_201_CREATED,
                        headers=headers)
```

Note

The above code uses `transaction.atomic` which was introduced in Django 1.6. It comes in handy in this case as it rolls back changes if something goes awry. See the Django documentation about transactions for more info:

https://docs.djangoproject.com/en/dev/topics/db/transactions/

Also, this example creates one `Component` instance, but creating several can be accomplished by either modifying the client to send one Component POST request at a time or modifying the above code.

Hope this helps!

Django Rest Framework - create objects passed as a list attribute of nested object

Solution

Problem