closes #768

cate/webapi/geojson.py

@@ -266,6 +266,7 @@ def write_feature_collection(feature_collection: Union[fiona.Collection, Iterabl
     io.flush()
 
     num_features_written = 0
+    feature_index = 0
     for feature in feature_collection:
         feature_ok = _transform_feature(feature,
                                         max_num_display_geometry_points,
@@ -277,10 +278,16 @@ def write_feature_collection(feature_collection: Union[fiona.Collection, Iterabl
                 io.flush()
             if res_id is not None:
                 feature['_resId'] = res_id
+            feature['_idx'] = feature_index
+            if 'id' not in feature:
+                feature['id'] = feature_index
             # Note: io.write(json.dumps(feature)) is 3x faster than json.dump(feature, fp=io)
-            io.write(json.dumps(feature))
+            json_text = json.dumps(feature)
+            io.write(json_text)
             num_features_written += 1
 
+        feature_index += 1
+
     io.write('\n]}\n')
     io.flush()
 
@@ -291,9 +298,9 @@ def write_feature(feature: Feature,
                   io,
                   crs=None,
                   res_id: int = None,
+                  feature_index: int = -1,
                   max_num_display_geometry_points: int = 100,
                   conservation_ratio: float = 1.0):
-
     source_prj = target_prj = None
     if crs:
         source_prj = pyproj.Proj(crs)
@@ -306,11 +313,17 @@ def write_feature(feature: Feature,
     if feature_ok:
         if res_id is not None:
             feature['_resId'] = res_id
+        feature['_idx'] = feature_index
+        if 'id' not in feature:
+            feature['id'] = feature_index
         # Note: io.write(json.dumps(feature)) is 3x faster than json.dump(feature, fp=io)
-        io.write(json.dumps(feature))
+        json_text = json.dumps(feature, cls=SeriesJSONEncoder)
+        io.write(json_text)
         io.flush()
 
 
+
+
 def _transform_feature(feature: Feature,
                        max_num_display_geometry_points: int,
                        conservation_ratio: float,
@@ -517,3 +530,16 @@ def _update_point(self, point):
             self._push(new_point)
             return new_point
         return point
+
+
+class SeriesJSONEncoder(json.JSONEncoder):
+    def default(self, obj):
+        if hasattr(obj, 'dtype'):
+            if np.issubdtype(obj.dtype, np.integer):
+                return int(obj)
+            elif np.issubdtype(obj.dtype, np.floating):
+                return float(obj)
+            else:
+                return str(obj)
+
+        return json.JSONEncoder.default(self, obj)

cate/webapi/rest.py

@@ -369,16 +369,13 @@ def get(self, base_dir, res_id, feature_index):
             elif isinstance(resource, gpd.GeoDataFrame):
                 if not self._check_feature_index(feature_index, len(resource)):
                     return
-                # TODO (nf,mz): review & test following code,
-                # it is inspired by geopandas.GeoDataFrame.iterfeatures() impl.
-                row = resource[feature_index]
+                row = resource.iloc[feature_index]
                 geometry = None
                 properties = row.to_dict()
                 if 'geometry' in properties:
                     geometry = row['geometry'].__geo_interface__
                     del properties['geometry']
                 feature = {
-                    'id': str(row.index),
                     'type': 'Feature',
                     'properties': properties,
                     'geometry': geometry
@@ -398,15 +395,18 @@ def get(self, base_dir, res_id, feature_index):
                 conservation_ratio = _level_to_conservation_ratio(level, _NUM_GEOM_SIMP_LEVELS)
 
                 def job():
-                    write_feature(feature,
-                                  self,
-                                  crs=crs,
-                                  res_id=res_id,
-                                  conservation_ratio=conservation_ratio)
+                    try:
+                        write_feature(feature,
+                                      self,
+                                      crs=crs,
+                                      res_id=res_id,
+                                      feature_index=feature_index,
+                                      conservation_ratio=conservation_ratio)
+                    except BaseException as e:
+                        self.write_status_error(exc_info=sys.exc_info())
                     self.finish()
                     if TRACE_PERF:
                         print('ResFeatureHandler: streaming done at ', datetime.datetime.now())
-                    self.finish()
 
                 yield [THREAD_POOL.submit(job)]
         except Exception:

test/webapi/test_geojson.py

@@ -123,10 +123,10 @@ class Collection(list):
                          '{"type": "FeatureCollection", "features": [\n'
                          '{"type": "Feature", "geometry": {"type": "Polygon", '
                          '"coordinates": [[[12.0, 53.0], [13.0, 54.0], [13.0, 56.0], [12.0, 53.0]]]}, '
-                         '"properties": {"id": "1", "a": 3, "b": true}},\n'
+                         '"properties": {"id": "1", "a": 3, "b": true}, "_idx": 0, "id": 0},\n'
                          '{"type": "Feature", "geometry": {"type": "Polygon", '
                          '"coordinates": [[[12.0, 73.0], [13.0, 74.0], [13.0, 76.0], [12.0, 73.0]]]}, '
-                         '"properties": {"id": "2", "a": 9, "b": false}}\n'
+                         '"properties": {"id": "2", "a": 9, "b": false}, "_idx": 1, "id": 1}\n'
                          ']}\n')
 
     def test_polygon_with_simp(self):
@@ -163,10 +163,10 @@ class Collection(list):
                          '{"type": "FeatureCollection", "features": [\n'
                          '{"type": "Feature", "geometry": {"type": "Polygon", '
                          '"coordinates": [[[12.0, 53.0], [13.0, 54.0], [13.0, 56.0], [12.0, 53.0]]]}, '
-                         '"properties": {"id": "1", "a": 3, "b": true}, "_simp": 1},\n'
+                         '"properties": {"id": "1", "a": 3, "b": true}, "_simp": 1, "_idx": 0, "id": 0},\n'
                          '{"type": "Feature", "geometry": {"type": "Polygon", '
                          '"coordinates": [[[12.0, 73.0], [13.0, 74.0], [13.0, 76.0], [12.0, 73.0]]]}, '
-                         '"properties": {"id": "2", "a": 9, "b": false}, "_simp": 1}\n'
+                         '"properties": {"id": "2", "a": 9, "b": false}, "_simp": 1, "_idx": 1, "id": 1}\n'
                          ']}\n')
 
     def test_countries_with_simp(self):