Fetching nested objects with Django REST framework - django

Question

I am attempting to fetch nested objects but not quite sure how to achieve this. My model is as shown:
class Brand(models.Model)
name = models.CharField(max_length=128)
class Size(models.Model)
name = models.CharField(max_length=128)
class Brand_Size(models.Model)
brand = models.ForeignKey(Brand)
size = models.ForeignKey(Size)
class Brand_Size_Location(models.Model)
location = models.ForeignKey(Location)
brand_size = models.ForeignKey(Brand_Size)
I filter objects in Brand_Size_Location by location which can occur 1..x. I want my serializer to output the results in terms of the model Brand (BrandSerializer). Since my resultset can be 1..x and furthermore the occurrence of Brand can be duplicates i would like to eliminate these aswell at the same time.

Answer 1

You should be able to do this fairly easily by including a serializer field in your BrandSerializer:
class BrandSerializer(serializers.ModelSerializer):
brand_sizes = BrandSizeSerializer(
source='brand_size_set',
read_only=True
)
class Meta:
model = Brand
fields = (
'id',
...add more fields you want here
'brand_sizes')
You can simlarly create the brand size serializer to nest the locations
Filtering on this relationship occurs in the view and will need a custom filter. Here's a basic example using a ListView:
class BrandFilter(django_filters.FilterSet):
location = django_filters.ModelMultipleChoiceFilter(
queryset=Brand_Size_Location.objects.all(),
name='brand_size__brand_size_location__location'
)
location_name = django_filters.CharFilter(
name='brand_size__brand_size_location__location__name'
)
class Meta:
model = Brand
fields = [
'location',
'location_name'
]
class BrandList(LoginRequiredMixin, generics.ListCreateAPIView):
model = Brand
serializer_class = BrandSerializer
filter_class = BrandFilter
You can then use query parameters to filter on the URL like:
http://somehost/api/brands/?location=42
which uses a PK to filter, or with the location name (assuming you have a name field in the Location model):
http://somehost/api/brands/?location_name=Atlantis