send update_cache_key a different way

src/c3nav/editor/api.py

@@ -320,10 +320,10 @@ class EditorViewSet(EditorViewSetMixin, ViewSet):
         else:
             raise ValidationError('No level or space specified.')
 
-        return Response({
-            'update_cache_key': update_cache_key,
-            'geometries': [self.conditional_geojson(obj, update_cache_key_match) for obj in results],
-        })
+        return Response(list(chain(
+            [('update_cache_key', update_cache_key)],
+            (self.conditional_geojson(obj, update_cache_key_match) for obj in results)
+        )))
 
     def conditional_geojson(self, obj, update_cache_key_match):
         if update_cache_key_match and not obj._affected_by_changeset:

src/c3nav/editor/static/editor/js/editor.js

@@ -698,9 +698,13 @@ editor = {
         $.getJSON(geometry_url, function(result) {
             var geometries = [], feature, new_cache = {}, feature_type, feature_id;
             // geometries cache logic
-            for (var i=0;i<result.geometries.length;i++) {
-                feature = result.geometries[i];
+            for (var i=0;i<result.length;i++) {
+                feature = result[i];
                 if (Array.isArray(feature)) {
+                    if (feature[0] === 'update_cache_key') {
+                        editor._last_geometry_update_cache_key = feature[1];
+                        continue;
+                    }
                     // load from cache
                     if (feature[0] in editor._last_geometry_cache) {
                         feature = editor._last_geometry_cache[feature[0]][feature[1]];
@@ -722,7 +726,6 @@ editor = {
                 geometries.push(feature);
             }
             editor._last_geometry_cache = new_cache;
-            editor._last_geometry_update_cache_key = result.update_cache_key;
 
             editor.map.removeLayer(editor._highlight_layer);
             editor._highlight_layer.clearLayers();