Convert MultiPolygon to FeatureCollection when downloading vector layer results

Author: stephanerestani-picterra

src/picterra/base_client.py

@@ -6,10 +6,12 @@
 import sys
 import time
 from collections.abc import Callable
+
 if sys.version_info >= (3, 8):
     from typing import Literal, TypedDict
 else:
     from typing_extensions import Literal, TypedDict
+
 from typing import Any, Generic, Iterator, TypeVar
 from urllib.parse import urlencode, urljoin
 
@@ -74,6 +76,19 @@ def _upload_file_to_blobstore(upload_url: str, filename: str):
         raise APIError(resp.text)
 
 
+def multipolygon_to_feature_collection(mp):
+    return {
+        "type": "FeatureCollection",
+        "features": [{
+            "type": "Feature",
+            "properties": {},
+            "geometry": {
+                "type": "Polygon",
+                "coordinates": p
+            }
+        } for p in mp]
+    }
+
 T = TypeVar("T")
 
 

src/picterra/detector_platform_client.py

@@ -12,10 +12,12 @@
 import sys
 import tempfile
 import warnings
+
 if sys.version_info >= (3, 8):
     from typing import Literal
 else:
     from typing_extensions import Literal
+
 from typing import Any
 
 import requests
@@ -26,6 +28,7 @@
     FeatureCollection,
     _download_to_file,
     _upload_file_to_blobstore,
+    multipolygon_to_feature_collection,
 )
 
 logger = logging.getLogger()
@@ -836,13 +839,19 @@ def download_vector_layer_to_file(self, vector_layer_id: str, filename: str):
 
         Args:
             vector_layer_id: The id of the vector layer to download
-            filename: existing file to save the vector layer in
+            filename: existing file to save the vector layer in, as a feature collection
         """
         resp = self.sess.post(self._full_url("vector_layers/%s/download/" % vector_layer_id))
         if not resp.ok:
             raise APIError(resp.text)
         op = self._wait_until_operation_completes(resp.json())
-        _download_to_file(op["results"]["download_url"], filename)
+        # The operation results is a multipolygon that we convert to a feature collection
+        with tempfile.NamedTemporaryFile() as tmp:
+            _download_to_file(op["results"]["download_url"], tmp.name)
+            with open(tmp.name) as f:
+                mp = json.load(f)
+        with open(filename, "wt") as out_f:
+            json.dump(multipolygon_to_feature_collection(mp), out_f)
 
     def list_raster_markers(
         self,

tests/test_client.py

@@ -7,6 +7,7 @@
 import responses
 from requests.exceptions import ConnectionError
 
+from picterra.base_client import multipolygon_to_feature_collection
 from picterra.detector_platform_client import DetectorPlatformClient
 from tests.utils import (
     OP_RESP,
@@ -399,7 +400,7 @@ def add_mock_vector_layer_download_responses(layer_id, num_features):
         url,
         body=json.dumps(mp),
     )
-    return mp
+    return multipolygon_to_feature_collection(mp)
 
 
 def make_geojson_multipolygon(npolygons=1):
@@ -999,11 +1000,11 @@ def test_download_vector_layer_to_file(monkeypatch):
     client = _client(monkeypatch)
     with tempfile.NamedTemporaryFile() as fp:
         client.download_vector_layer_to_file("foobar", fp.name)
-        mp = json.load(fp)
+        fc = json.load(fp)
         assert (
-            mp["type"] == "MultiPolygon"
+            fc["type"] == "FeatureCollection"
         )
-        assert mp == expected_content and len(mp["coordinates"]) == 2
+        assert fc == expected_content and len(fc["features"]) == 2
     assert len(responses.calls) == 3 # POST /download, GET /operations, GET url