[beta] Add function to download a vector layer

Author: ao-picterra

setup.py

@@ -4,7 +4,7 @@
 
 setup(
     name="picterra",
-    version="1.1.0",
+    version="1.2.0",
     description="Picterra API client",
     package_dir={"": "src"},
     packages=find_packages("src"),

src/picterra/client.py

@@ -41,13 +41,11 @@ def request(self, *args, **kwargs):
 
 
 def _download_to_file(url, filename):
-    if not (os.path.exists(filename) and os.path.isfile(filename)):
-        raise ValueError("Invalid file: " + filename)
     # Given we do not use self.sess the timeout is disabled (requests default), and this
     # is good as file download can take a long time
     with requests.get(url, stream=True) as r:
         r.raise_for_status()
-        with open(filename, "wb") as f:
+        with open(filename, "wb+") as f:
             logger.debug("Downloading to file %s.." % filename)
             for chunk in r.iter_content(chunk_size=CHUNK_SIZE_BYTES):
                 if chunk:  # filter out keep-alive new chunks
@@ -943,6 +941,30 @@ def delete_vector_layer(self, vector_layer_id: UUID):
         if not resp.ok:
             raise APIError(resp.text)
 
+    def download_vector_layer_to_file(self, vector_layer_id: UUID, filename: str):
+        """
+        Downloads a vector layer
+
+        This a **beta** function, subject to change.
+
+        Args:
+            vector_layer_id: The id of the vector layer to download
+            filename: existing file to save the vector layer in
+        """
+        resp = self.sess.get(self._api_url("vector_layers/%s/" % vector_layer_id))
+        if not resp.ok:
+            raise APIError(resp.text)
+        urls = resp.json()["geojson_urls"]
+        final_fc = {"type": "FeatureCollection", "features": []}
+        for url in urls:
+            with tempfile.NamedTemporaryFile("w+") as f:
+                _download_to_file(url, f.name)
+                fc = json.load(f)
+                for feature in fc["features"]:
+                    final_fc["features"].append(feature)
+        with open(filename, "w") as fp:
+            json.dump(final_fc, fp)
+
     def list_raster_markers(self, raster_id):
         """
         This a **beta** function, subject to change.

tests/test_client.py

@@ -337,6 +337,40 @@ def add_mock_vector_layer_responses(upload_id, raster_id, name, color):
     )
 
 
+def add_mock_vector_layer_download_responses(layer_id, urls_num=1):
+    url = "vector_layers/%s/" % layer_id
+    data = {
+        "name": "layer%s" % layer_id,
+        "raster_id": "raster-id",
+        "count": 1,
+        "color": "#aa0000",
+        "id": layer_id,
+        "geojson_urls": [
+            "http://layer%s.geojson.example.com" % str(i) for i in range(urls_num)
+        ],
+    }
+    _add_api_response(url, json=data)
+    features = []
+    for i in range(urls_num):
+        url = "http://layer%s.geojson.example.com" % str(i)
+        temp_features = [
+            {
+                "type": "Feature",
+                "geometry": make_geojson_multipolygon(j + 1),
+                "properties": {},
+            }
+            for j in range(i + 1)
+        ]
+        for f in temp_features:
+            features.append(f)
+        responses.add(
+            responses.GET,
+            url,
+            body=json.dumps({"type": "FeatureCollection", "features": temp_features}),
+        )
+    return {"type": "FeatureCollection", "features": features}
+
+
 def make_geojson_multipolygon(npolygons=1):
     coords = []
     for i in range(npolygons):
@@ -872,6 +906,20 @@ def test_edit_vector_layer():
     assert len(responses.calls) == 1
 
 
+@responses.activate
+def test_download_vector_layer_to_file():
+    expected_content = add_mock_vector_layer_download_responses("foobar", 2)
+    client = _client()
+    with tempfile.NamedTemporaryFile() as fp:
+        client.download_vector_layer_to_file("foobar", fp.name)
+        fc = json.load(fp)
+        assert fc == expected_content and len(fc["features"]) == 3
+        assert (
+            fc["type"] == "FeatureCollection" and fc["features"][0]["type"] == "Feature"
+        )
+    assert len(responses.calls) == 3
+
+
 @responses.activate
 def test_list_raster_markers():
     client = _client()