如何捕获从 Future[HttpResponse] scala 抛出的异常

Question

I am new to scala. I am using the HTTP-client of scala to hit another server. Where the response returned is Future[HttpResponse]. Here is something that I have:

pathPrefix("run") {
    post {
        entity(as[InputRequest]) { inputRequest =>
            complete {
               runService(inputRequest)
            }
        }
    }
}

def runService(inputRequest:InputRequest) : Future[HttpResponse] = {
    val pipeline: HttpRequest => Future[HttpResponse] = sendReceive  ~> unmarshal[HttpResponse]
    val response: Future[HttpResponse] = pipeline(Post("some-hostname", inputRequest)
    ~> addCredentials(BasicHttpCredentials("user", "pass"))

    response
}

So if something fails(like 500 internal server error) from response, How to catch its exception?

Answer 1

Couple of ways to do it:

Using rejection handler directive:

handleRejections(/*your custom rejection handler || default*/) {
  pathPrefix("run") {
  ...
}

Or recover Future :

response.recover {
  case t => // t is Throwable, do something with it
}

The return type of your function def runService(inputRequest:InputRequest) : Future[HttpResponse] will then change depending on what your recover evaluates to