I'm using DRF for a simple API, and I was wondering if there's a way to achieve this behavior:
- I've got two models similar to the following:
class Table(models.Model):
name = models.CharField(max_length=100)
...
class Column(models.Model):
original_name = models.CharField(max_length=100)
name = models.CharField(max_length=100, blank=True, null=True)
...
table = models.ForeignKey(Table, on_delete=models.CASCADE, related_name="columns")
- And their serializers as follows:
class ColumnSerializer(serializers.HyperlinkedModelSerializer):
table = serializers.HyperlinkedRelatedField(
read_only=True, view_name="table-detail"
)
class Meta:
model = Column
fields = ["url", "name", "table"]
class TableSerializer(serializers.HyperlinkedModelSerializer):
dataset = serializers.HyperlinkedRelatedField(
read_only=True, view_name="dataset-detail"
)
tags = serializers.SlugRelatedField(
many=True, slug_field="name", queryset=Tag.objects.all()
)
columns = ColumnSerializer(many=True, read_only=True)
class Meta:
model = Table
fields = [
"url",
"name",
...
"columns",
]
- This returns me an output similar to
{
...
"results": [
{
"url": "http://0.0.0.0:8001/api/tables/1/",
"name": "some-name",
"columns": [
{
"url": "http://0.0.0.0:8001/api/columns/1/",
"name": "id",
"table": "http://0.0.0.0:8001/api/tables/1/"
},
...
}
which is totally fine. But what I'd really want to do is, if a Column
has name=None
, it's filtered out from every API ViewSet. I've managed to do it on the ColumnViewSet
by doing queryset = queryset.filter(name__isnull=False)
, but I can't do it for the TableViewSet
or others that might show a Column
list.
I've tried tinkering with the ColumnSerializer
, but the best I could get from it was to show null
s on the Column
list.
I wonder if there's a way of hiding those.
EDIT 1: Adding my ViewSets
class TableViewSet(viewsets.ModelViewSet):
serializer_class = TableSerializer
def get_queryset(self):
queryset = Table.objects.all().order_by("name")
# some query_params filtering
return queryset
class ColumnViewSet(viewsets.ModelViewSet):
serializer_class = ColumnSerializer
def get_queryset(self):
queryset = Column.objects.all().order_by("id")
queryset = queryset.filter(name__isnull=False)
# some query_params filtering
return queryset
CodePudding user response:
You can work with a Prefetch
object [Django-doc] to filter the related object collection, so:
from django.db.models import Prefetch
class TableViewSet(viewsets.ModelViewSet):
serializer_class = TableSerializer
def get_queryset(self):
queryset = Table.objects.prefetch_related(
Prefetch('columns', Column.objects.filter(name__isnull=False))
).order_by('name')
# some query_params filtering
return queryset