onSuccess

def onSuccess(unitFuture: Future[Unit]): Directive0
def onSuccess(simpleTypeFuture: Future[T]): Directive1[T]
def onSuccess(hlistFuture: Future[T_0 :: ... T_i ... :: HNil]): Directive[T_0 :: ... T_i ... :: HNil]

Description

Evaluates its parameter of type Future[T]CompletionStage<T>, and once it has been completed successfully, extracts its result as a value of type T and passes it to the inner route.

If the future fails its failure throwable is bubbled up to the nearest ExceptionHandlerExceptionHandler.

To handle the Failure case manually as well, use onComplete, instead.

Example

Scala

copysourceval route =
  concat(
    path("success") {
      onSuccess(Future { "Ok" }) { extraction =>
        complete(extraction)
      }
    },
    path("failure") {
      onSuccess(Future.failed[String](TestException)) { extraction =>
        complete(extraction)
      }
    }
  )

// tests:
Get("/success") ~> route ~> check {
  responseAs[String] shouldEqual "Ok"
}

Get("/failure") ~> Route.seal(route) ~> check {
  status shouldEqual InternalServerError
  responseAs[String] shouldEqual "Unsuccessful future!"
}

Java

copysourceimport static akka.http.javadsl.server.Directives.complete;
import static akka.http.javadsl.server.Directives.onSuccess;
import static akka.http.javadsl.server.Directives.path;

final Route route = path("success", () ->
        onSuccess(CompletableFuture.supplyAsync(() -> "Ok"),
                extraction -> complete(extraction)
        )
).orElse(path("failure", () ->
        onSuccess(CompletableFuture.supplyAsync(() -> {
                    throw new RuntimeException();
                }),
                extraction -> complete("never reaches here"))
));

testRoute(route).run(HttpRequest.GET("/success"))
        .assertEntity("Ok");

testRoute(route).run(HttpRequest.GET("/failure"))
        .assertStatusCode(StatusCodes.InternalServerError())
        .assertEntity("There was an internal server error.");