Bubbles up the given error through the route structure where it is dealt with by the closest handleExceptions directive and its ExceptionHandler.


def failWith(error: Throwable): StandardRoute 


failWith explicitly raises an exception that gets bubbled up through the route structure to be picked up by the nearest handleExceptions directive. If no handleExceptions is present above the respective location in the route structure The runRoute Wrapper will handle the exception and translate it into a corresponding HttpResponse using the in-scope ExceptionHandler (see also the Exception Handling chapter).

There is one notable special case: If the given exception is a RejectionError exception it is not bubbled up, but rather the wrapped exception is unpacked and “executed”. This allows the “tunneling” of a rejection via an exception.


val route =
  path("foo") {
    failWith(new RequestProcessingException(StatusCodes.BandwidthLimitExceeded))

Get("/foo") ~> sealRoute(route) ~> check {
  status === StatusCodes.BandwidthLimitExceeded
  responseAs[String] === "Bandwidth limit has been exceeded."