Add coordinate filter on the backend

- filters plants based on ecological region and soil order

backend/right_tree/api/filters.py

@@ -0,0 +1,28 @@
+import json
+
+from django.contrib.gis.geos import Point
+from django.db.models import Q
+
+from .models import EcologicalRegion, EcologicalDistrictLayer, SoilOrder
+
+
+def coordinate_filter(request, queryset):
+    coordinates = request.query_params.get('coordinates')
+
+    if coordinates is not None:
+        coordinates_json = json.loads(coordinates)
+        pnt = Point(coordinates_json["lng"],
+                    coordinates_json["lat"], srid=4326)
+        pnt.transform(2193)
+
+        filtered_regions = EcologicalRegion.objects.filter(
+            ecologicaldistrictlayer__geom__intersects=pnt).values_list('id', flat=True)
+        filtered_soil_orders = SoilOrder.objects.filter(
+            soillayer__geom__intersects=pnt).values_list('id', flat=True)
+
+        # Filter by ecological regions and soil orders
+        return queryset.filter(
+            Q(ecological_regions__in=filtered_regions) &
+            Q(soil_order__in=filtered_soil_orders))
+
+    return queryset

backend/right_tree/api/views.py

@@ -1,6 +1,7 @@
 from rest_framework import viewsets
 from right_tree.api.models import Plant
 from right_tree.api.serializers import PlantSerializer
+from .filters import coordinate_filter
 
 class PlantViewSet(viewsets.ModelViewSet):
     """
@@ -8,3 +9,13 @@ class PlantViewSet(viewsets.ModelViewSet):
     """
     queryset = Plant.objects.all()
     serializer_class = PlantSerializer
+
+    def get_queryset(self):
+        """ Filtering plant query set by query parameters in the URL.
+            (May want to eventually use django filters to break up the logic...)
+        """
+        queryset = Plant.objects.all()
+        queryset = coordinate_filter(self.request, queryset)
+
+        return queryset
+