How to fetch parent child hierarchy using django rest-framework - django

Question

I am new to Django rest-framework. I am writing an API to fetch details in a parent-child hierarchy. Following is my code;
models.py
class ConfigAttributes(models.Model):
attr_set_name = models.CharField(max_length=32)
product_type = models.CharField(max_length=32)
class ProductInfo(models.Model):
config_attr = models.ForeignKey(ConfigAttributes, on_delete=models.CASCADE)
product_name = models.CharField(max_length=32)
class AttributeDetails(models.Model):
product_info = models.ForeignKey(ProductInfo, on_delete=models.CASCADE)
attribute_name = models.CharField(max_length=32)
serializers.py
class ConfigAttributesSerializer(serializers.ModelSerializer):
class Meta:
model = ConfigAttributes
fields = ['id', 'attr_set_name', 'product_type']
class ProductInfoSerializer(serializers.ModelSerializer):
class Meta:
model = ProductInfo
fields = ['id', 'product_name', 'config_attr_id']
class AttributeDetailsSerializer(serializers.ModelSerializer):
class Meta:
model = AttributeDetails
fields = ['id', 'attribute_name', 'product_info_id']
views.py
class ConfigAttributesViewSet(viewsets.ModelViewSet):
queryset = ConfigAttributes.objects.all()
serializer_class = ConfigAttributesSerializer
class ProductInfoViewSet(viewsets.ModelViewSet):
queryset = ProductInfo.objects.all()
serializer_class = ProductInfoSerializer
class AttributeDetailsViewSet(viewsets.ModelViewSet):
queryset = AttributeDetails.objects.all()
serializer_class = AttributeDetailsSerializer
and app/urls.py
router = routers.DefaultRouter()
router.register('config', ConfigAttributesViewSet)
router.register('product', ProductInfoViewSet)
router.register('attr', AttributeDetailsViewSet)
urlpatterns = [
path('', include(router.urls)),
]
When I call the API, my required hierarchy and output is;
[
{
"attr_set_name" : "abc",
"product_type" : "efg",
"product_info" : {
"product_name" : "hij",
"attribute_details" : {
"attribute_name" : "klm"
}
}
}
]
What are the changes need to done in the files to get the above output in hierarchy (I am using Postman to check my APIs). Thank you for the help.

Answer 1

You can nest your serializers. To match your general API hierarchy this is as close as you can get. Unfortunately, the relationship fields will be lists.
class AttributeDetailsSerializer(serializers.ModelSerializer):
class Meta:
model = AttributeDetails
fields = ['id', 'attribute_name', 'product_info_id']
class ProductInfoSerializer(serializers.ModelSerializer):
attribute_details = AttributeDetailsSerializer(many=True)
class Meta:
model = ProductInfo
fields = ['id', 'product_name', 'config_attr_id', 'attribute_details']
class ConfigAttributesSerializer(serializers.ModelSerializer):
product_infos = ProductInfoSerializer(many=True)
class Meta:
model = ConfigAttributes
fields = ['id', 'attr_set_name', 'product_type', 'product_infos']
You can get the specific parent elements if you start with the AttributeDetails instance though:
class ConfigAttributesSerializer(serializers.ModelSerializer):
class Meta:
model = ConfigAttributes
fields = ['id', 'attr_set_name', 'product_type',]
class ProductInfoSerializer(serializers.ModelSerializer):
config_attribute = ConfigAttributesSerializer(many=False)
class Meta:
model = ProductInfo
fields = ['id', 'product_name', 'config_attr_id', 'config_attribute']
class AttributeDetailsSerializer(serializers.ModelSerializer):
product_info = ProductInfoSerializer(many=False)
class Meta:
model = AttributeDetails
fields = ['id', 'attribute_name', 'product_info_id', 'product_info']