+
+
+def load_format_dispatcher(api_name: str, project_dir: Optional[Path]) -> FormatDispatcher:
+ """ Load the dispatcher for the given API.
+
+ The function first tries to find a module api/<api_name>/format.py
+ in the project directory. This file must export a single variable
+ `dispatcher`.
+
+ If the function does not exist, the default formatter is loaded.
+ """
+ if project_dir is not None:
+ priv_module = project_dir / 'api' / api_name / 'format.py'
+ if priv_module.is_file():
+ spec = importlib.util.spec_from_file_location(f'api.{api_name},format',
+ str(priv_module))
+ if spec:
+ module = importlib.util.module_from_spec(spec)
+ # Do not add to global modules because there is no standard
+ # module name that Python can resolve.
+ assert spec.loader is not None
+ spec.loader.exec_module(module)
+
+ return cast(FormatDispatcher, module.dispatch)
+
+ return cast(FormatDispatcher,
+ importlib.import_module(f'nominatim_api.{api_name}.format').dispatch)