DatasetDirectoryHandlerFunction
class DatasetDirectoryHandlerFunction(gateways: DatasetQueryGateways, exceptionHandler: RequestExceptionHandler) : HandlerFunction<ServerResponse>
GET /dataset: the datasets this instance serves, by name, as of the request (dataset platform design §4.4). Who may see the directory, and each dataset, is the gateway's path rules' to decide; the directory adds no access model.