Sorting by distance filter for django-restframework-gis. MIT license.

filters.py

# -*- coding: utf-8 -*-

"""
This is an extension to django-restframework-gis that extends on
DistanceToPointFilter and adds sorting by distance.

It is also possible to add a extra distance field to the returned queryset by
adding the flag distance_filter_add_distance = True to the DRF View.
"""

from rest_framework_gis.filters import DistanceToPointFilter


class OrderedDistanceToPointFilter(DistanceToPointFilter):
    def filter_queryset(self, request, queryset, view):
        """
        Add sorting by distance, in addition to DinstanceToPointerFilter filter
        """
        if not request.query_params.get(self.point_param, None):
            return queryset

        point = self.get_filter_point(request)

        queryset = super(OrderedDistanceToPointFilter, self)\
            .filter_queryset(request, queryset, view)

        queryset = queryset.distance(point)
        queryset = queryset.order_by('%s' % 'distance')

        add_distance = getattr(view, 'distance_filter_add_distance', False)
        if add_distance:
            queryset = self.apply_distance_field(request, queryset, view)

        return queryset

    def apply_distance_field(self, request, queryset, view):
        """
        Adds distance info (in meters) to queryset
        """

        for item in queryset:
            item.distance = item.distance.m

        return queryset