Raise an exception when trying to save camera snapshots to a not allowed path (#91869)

homeassistant/components/camera/__init__.py

@@ -56,6 +56,7 @@ from homeassistant.helpers.entity import Entity, EntityDescription
 from homeassistant.helpers.entity_component import EntityComponent
 from homeassistant.helpers.event import async_track_time_interval
 from homeassistant.helpers.network import get_url
+from homeassistant.helpers.template import Template
 from homeassistant.helpers.typing import ConfigType
 from homeassistant.loader import bind_hass
 
@@ -912,15 +913,16 @@ async def async_handle_snapshot_service(
 ) -> None:
     """Handle snapshot services calls."""
     hass = camera.hass
-    filename = service_call.data[ATTR_FILENAME]
+    filename: Template = service_call.data[ATTR_FILENAME]
     filename.hass = hass
 
     snapshot_file = filename.async_render(variables={ATTR_ENTITY_ID: camera})
 
     # check if we allow to access to that file
     if not hass.config.is_allowed_path(snapshot_file):
-        _LOGGER.error("Can't write %s, no access to path!", snapshot_file)
+        raise HomeAssistantError(
-        return
+            f"Cannot write `{snapshot_file}`, no access to path; `allowlist_external_dirs` may need to be adjusted in `configuration.yaml`"
+        )
 
     image = await camera.async_camera_image()
 

tests/components/camera/test_init.py

@@ -245,6 +245,26 @@ async def test_snapshot_service(hass: HomeAssistant, mock_camera) -> None:
         assert mock_write.mock_calls[0][1][0] == b"Test"
 
 
+async def test_snapshot_service_not_allowed_path(
+    hass: HomeAssistant, mock_camera
+) -> None:
+    """Test snapshot service with a not allowed path."""
+    mopen = mock_open()
+
+    with patch("homeassistant.components.camera.open", mopen, create=True), patch(
+        "homeassistant.components.camera.os.makedirs",
+    ), pytest.raises(HomeAssistantError, match="/test/snapshot.jpg"):
+        await hass.services.async_call(
+            camera.DOMAIN,
+            camera.SERVICE_SNAPSHOT,
+            {
+                ATTR_ENTITY_ID: "camera.demo_camera",
+                camera.ATTR_FILENAME: "/test/snapshot.jpg",
+            },
+            blocking=True,
+        )
+
+
 async def test_websocket_stream_no_source(
     hass: HomeAssistant, hass_ws_client: WebSocketGenerator, mock_camera, mock_stream
 ) -> None: