[fix] Deserialize id_field #272

When serializing a model, the value of its `id_field` is written in the `id` attribute
of the GeoJSON feature.

This behaviour is however not mirrored by the deserialization logic: deserializing a
model through GeoFeatureModelSerializer ignores the `id` field set in the given GeoJSON
feature.

This commit solves this issue by mirroring the serialization logic:
- When deserializing a model, the `id` attribute of the GeoJSON feature is written as the
`id_field` of the django model.

Fixes #272

Signed-off-by: Stephane Restani <stephane.restani@picterra.ch>

rest_framework_gis/serializers.py

@@ -214,6 +214,9 @@ def unformat_geojson(self, feature):
         if 'geometry' in feature:
             attrs[self.Meta.geo_field] = feature['geometry']
 
+        if self.Meta.id_field and 'id' in feature:
+            attrs[self.Meta.id_field] = feature['id']
+
         if self.Meta.bbox_geo_field and 'bbox' in feature:
             attrs[self.Meta.bbox_geo_field] = Polygon.from_bbox(feature['bbox'])
 

tests/django_restframework_gis_tests/serializers.py

@@ -107,6 +107,17 @@ class Meta:
         fields = ('name',)
 
 
+class LocationGeoFeatureWritableIdSerializer(LocationGeoFeatureSerializer):
+    """ default id attribute  """
+
+    class Meta:
+        model = Location
+        geo_field = 'geometry'
+        fields = ('id', 'name', 'timestamp')
+
+    id = serializers.CharField()
+
+
 class LocatedFileGeoFeatureSerializer(gis_serializers.GeoFeatureModelSerializer):
     """ located file geo serializer  """
 

tests/django_restframework_gis_tests/tests.py

@@ -329,6 +329,22 @@ def test_geojson_false_id_attribute_slug(self):
         with self.assertRaises(KeyError):
             response.data['id']
 
+    def test_post_geojson_id_attribute(self):
+        self.assertEqual(Location.objects.count(), 0)
+        data = {
+            "type": "Feature",
+            "id": "42",
+            "properties": {"name": "point"},
+            "geometry": {"type": "Point", "coordinates": [10.1, 10.1]},
+        }
+        url = reverse('api_geojson_location_writable_id_list')
+        response = self.client.post(
+            url, data=json.dumps(data), content_type='application/json',
+        )
+        self.assertEqual(response.status_code, 201)
+        self.assertEqual(Location.objects.count(), 1)
+        self.assertEqual(Location.objects.first().id, 42)
+
     def test_geojson_no_id_attribute_slug(self):
         location = Location.objects.create(
             name='noid test', geometry='POINT (10.1 10.1)'

tests/django_restframework_gis_tests/urls.py

@@ -7,6 +7,11 @@
     path('<int:pk>', views.location_details, name='api_location_details'),
     # geojson
     path('geojson/', views.geojson_location_list, name='api_geojson_location_list'),
+    path(
+        'geojson_writable_id/',
+        views.geojson_location_writable_id_list,
+        name='api_geojson_location_writable_id_list',
+    ),
     path(
         'geojson/<int:pk>/',
         views.geojson_location_details,

tests/django_restframework_gis_tests/views.py

@@ -21,6 +21,7 @@
     LocationGeoFeatureNoIdSerializer,
     LocationGeoFeatureSerializer,
     LocationGeoFeatureSlugSerializer,
+    LocationGeoFeatureWritableIdSerializer,
     LocationGeoSerializer,
     NoneGeoFeatureMethodSerializer,
     PaginatedLocationGeoSerializer,
@@ -57,6 +58,16 @@ class GeojsonLocationList(generics.ListCreateAPIView):
 geojson_location_list = GeojsonLocationList.as_view()
 
 
+class GeojsonLocationWritableIdList(generics.ListCreateAPIView):
+    model = Location
+    serializer_class = LocationGeoFeatureWritableIdSerializer
+    queryset = Location.objects.all()
+    pagination_class = GeoJsonPagination
+
+
+geojson_location_writable_id_list = GeojsonLocationWritableIdList.as_view()
+
+
 class GeojsonLocationContainedInBBoxList(generics.ListAPIView):
     model = Location
     serializer_class = LocationGeoFeatureSerializer