Update how the application configuration is read for LabThings 0.0.17

src/openflexure_microscope_server/things/__init__.py

@@ -7,9 +7,6 @@ with other Things and including them in the LabThings-FastAPI config file.
 import posixpath
 from typing import Optional, Self
 
-from starlette.routing import Mount
-from starlette.staticfiles import StaticFiles
-
 import labthings_fastapi as lt
 
 
@@ -20,7 +17,13 @@ class OFMThing(lt.Thing):
 
     def __enter__(self) -> Self:
         """Set the data directory when the Thing is entered."""
-        self._data_dir = get_data_directory_from_server(self)
+        # Note that the `application_config` was already validated when the
+        # server initialised.
+        application_config = self._thing_server_interface.application_config
+        if application_config is None:
+            raise ValueError("No application configuration was supplied.")
+        app_data_dir = application_config["data_folder"]
+        self._data_dir = posixpath.join(str(app_data_dir), self.path.strip("/"))
         return self
 
     @property
@@ -31,31 +34,3 @@ class OFMThing(lt.Thing):
                 "No data directory set. Has the LabThings server been started?"
             )
         return self._data_dir
-
-
-def get_data_directory_from_server(thing: lt.Thing) -> str:
-    """Get the data directory from the server.
-
-    :param thing: The Thing to get the data directory for.
-
-    :return: The data directory as a string:
-    :raise RuntimeError: If not able to get the data directory for any reason.
-    """
-    server = thing._thing_server_interface._server()
-    if server is None:
-        raise RuntimeError("No server found to communicate with.")
-    routes = server.app.routes
-    try:
-        route_paths = [route.path if hasattr(route, "path") else "" for route in routes]
-        data_index = route_paths.index("/data")
-    except ValueError as e:
-        raise RuntimeError("Could not find data directory") from e
-    mount = routes[data_index]
-    if not isinstance(mount, Mount):
-        raise RuntimeError("Data directory isn't a starlette.routing.Mount.")
-    if not isinstance(mount.app, StaticFiles):
-        raise RuntimeError("Data is not mounted as static files.")
-    app_data_dir = mount.app.directory
-    if app_data_dir is None:
-        raise RuntimeError("Data directory is not set.")
-    return posixpath.join(str(app_data_dir), thing.path.strip("/"))