Drf Filtering Django Filter

ViewSet Integration

from django_filters.rest_framework import DjangoFilterBackend
from rest_framework import viewsets, filters

class FirmwareViewSet(viewsets.ModelViewSet):
    queryset = Firmware.objects.select_related("brand").all()
    serializer_class = FirmwareSerializer
    filter_backends = [DjangoFilterBackend, filters.SearchFilter, filters.OrderingFilter]
    filterset_class = FirmwareFilter
    search_fields = ["name", "version"]
    ordering_fields = ["created_at", "file_size"]

Shorthand (Without FilterSet Class)

class BrandViewSet(viewsets.ReadOnlyModelViewSet):
    queryset = Brand.objects.all()
    serializer_class = BrandSerializer
    filter_backends = [DjangoFilterBackend]
    filterset_fields = {
        "name": ["exact", "icontains"],
        "country": ["exact"],
        "is_active": ["exact"],
    }

Boolean Filter

class DeviceFilter(django_filters.FilterSet):
    is_trusted = django_filters.BooleanFilter(field_name="trust_score", method="filter_trusted")

    class Meta:
        model = Device
        fields = ["is_trusted"]

    def filter_trusted(self, queryset, name, value):
        if value:
            return queryset.filter(trust_score__gte=80)
        return queryset.filter(trust_score__lt=80)

Multiple Value Filter (IN Lookup)

class FirmwareFilter(django_filters.FilterSet):
    brand_id = django_filters.BaseInFilter(
        field_name="brand_id", lookup_expr="in"
    )
    # Usage: ?brand_id=1,2,3

    class Meta:
        model = Firmware
        fields = ["brand_id"]

Date Range Filter

class AuditLogFilter(django_filters.FilterSet):
    date_from = django_filters.DateFilter(field_name="created_at", lookup_expr="gte")
    date_to = django_filters.DateFilter(field_name="created_at", lookup_expr="lte")

    class Meta:
        model = AuditLog
        fields = ["date_from", "date_to", "action"]

Request URL Examples

GET /api/v1/firmwares/?brand=samsung&status=active
GET /api/v1/firmwares/?min_size=1000000&created_after=2025-01-01
GET /api/v1/firmwares/?brand_id=1,2,3
GET /api/v1/audit/?date_from=2025-06-01&date_to=2025-06-30&action=login

Anti-Patterns

• filterset_fields = "__all__" — exposes internal fields to filtering
• Missing DjangoFilterBackend in filter_backends → filters silently ignored
• Filtering on non-indexed columns for large tables → slow queries
• Complex filter logic in ViewSet instead of FilterSet → scattered code

Quality Gate

& .\.venv\Scripts\python.exe -m ruff check . --fix
& .\.venv\Scripts\python.exe -m ruff format .
& .\.venv\Scripts\python.exe manage.py check --settings=app.settings_dev

References

• Skill: drf-filtering-search — SearchFilter patterns
• Skill: drf-filtering-ordering — OrderingFilter patterns