How to add annotate data in django-rest-framework queryset responses

Question

I am generating aggregates for each item in a QuerySet:

def get_queryset(self):
    from django.db.models import Count
    queryset = Book.objects.annotate(Count('authors'))
    return queryset

But I am not getting the count in the JSON response.

thank you in advance

Answer 1

Hello @kartik,

The queryset returned from get_queryset provides the list of things that will go through the serializer, which controls how the objects will be represented. Try adding an additional field in your Book serializer, like:

author_count = serializers.IntegerField(
    source='author_set.count', 
    read_only=True
)

Hope this helps!!