Do case-insensitive ordering with django-filter

Question

Is it possible to do case-insensitive ordering by first_name with Django-rest-framework.

Here is the code:

import django_filter

class PersonFilter(django_filters.FilterSet):
    class Meta:
        model = Person
        fields = ('first_name_lower',)
        order_by = ('first_name_lower',)

class PersonViewSet(BaseModelViewSet):
    queryset = Person.objects.all()
    permission_classes = (permissions.IsAuthenticated,)
    filter_backends = (filters.DjangoFilterBackend,)
    filter_class = PersonFilter

Is there an easy way to do case-insensitive ordering with django-filter?

Here django-filter has docs for case-insensitive search, but nothing for ordering.

In the Django docs, the code is somewhat obtuse for this, which makes me wonder if it exists for django-filter or not. Here's the Django docs code snippet on how to do it with the Django ORM:

>>> from django.db.models.functions import Lower
>>> MyModel.objects.order_by(Lower('myfield'))

Answer 1

You might want to subclass the OrderingFilter and use it as your filter_backend so that you can reuse the code.

from rest_framework.filters import OrderingFilter
from django.db.models.functions import Lower

class CaseInsensitiveOrderingFilter(OrderingFilter):
    def filter_queryset(self, request, queryset, view):
        ordering = self.get_ordering(request, queryset, view)

        if ordering is not None:
            if ordering.startswith('-'):
                queryset = queryset.order_by(Lower(ordering[1:])).reverse()
            else:
                queryset = queryset.order_by(Lower(ordering))
        return queryset


class PersonViewSet(ModelViewSet):
    queryset = Person.objects.all()
    serializer_class = MySerializer
    permission_classes = (permissions.IsAuthenticated,)
    filter_backends = (CaseInsensitiveOrderingFilter,)