从Actor返回实际结果而不是Promise/Future

Question

我正在尝试用Akka / Scala编写一个actor，调用HTTP REST API并将结果发送回调用actor。API 可能会返回结果的集合/向量，必须首先将其转换为内部供应商中性格式，以便将来可以更改供应商，而无需对代码进行太多更改。大多数代码都在工作，但我不知道如何解压缩并发送内部向量。

这是我拥有的代码，它向调用的Actor返回一个Promise。我想返回的是最终映射操作中创建的实际向量：

class RESTActor extends Actor with ActorLogging with JsonSupport {

  final implicit val materializer: ActorMaterializer = ActorMaterializer(ActorMaterializerSettings(context.system))
  val http = Http(context.system)

  import akka.pattern.pipe
  import context.dispatcher

  override def receive: Receive = {
    case query: String => {
      val requester = sender
      var uri = Uri(Settings.autoCompleteURL).withQuery(Query(Map("query" -> query)))

      sender! http
        .singleRequest(HttpRequest(HttpMethods.GET, uri = uri))
        .flatMap(response =>
          response.status match {
            case status if status.isSuccess() => Unmarshal(response.entity).to[VendorResponse].map(_.result.map(x => VendorNeutralResponse(x.id, x.field)))

            case _ => response.entity.toStrict(5.seconds).map { entity =>
              val body = entity.data.decodeString("UTF-8")
              log.warning(errorMessage(response, body))
              Left(errorMessage(response, body))
            }

          })
    }

  }

主叫演员：

pathPrefix("search") {
          get {
            parameter("query") { query =>
              {
                complete(restActor.ask(query)) //Doesn't work as the reply is a promise

              }
            }
          }
        }

如何在重启器中更改上述代码，以将实际结果发送回，而不是发送未来或promise？

编辑:根据我自己的研究和@micha和@cyrille-corpet的建议修改代码后，下面的代码工作了:

pathPrefix("search") {
          get {
            parameter("query") { query =>
              {
                onComplete(gisRouter.ask(query)) {
                  case Success(resp: Future[Vector[VendorNeutralResponse]]) => {
                    resp.map(println)
                    complete("ok")
                  }
                  case Failure(e) => complete(e.toString)
                }

              }
            }
          }
        }

看起来我还是能从我的演员那里得到一个< code >未来的回应。我如何让参与者用实际数据而不是< code >未来来回应？

Answer 1

你可以使用map来做它：

pathPrefix("search") {
  get {
    parameter("query") { query =>
      restActor.ask(query) map {
        case Success(resp) => ...
        case Failure(e) => ...
      }
    }
  }
}

编辑:目前你的演员回答未来。尝试重构它，使它返回未包装的值:

class RESTActor extends Actor with ActorLogging with JsonSupport {

  final implicit val materializer: ActorMaterializer = ActorMaterializer(ActorMaterializerSettings(context.system))
  val http = Http(context.system)

  import akka.pattern.pipe
  import context.dispatcher

  private def handleHttpResponse = {
    case status if status.isSuccess() => Unmarshal(response.entity).to[VendorResponse].map(_.result.map(x => VendorNeutralResponse(x.id, x.field)))

    case _ => response.entity.toStrict(5.seconds).map { entity =>
      val body = entity.data.decodeString("UTF-8")
      log.warning(errorMessage(response, body))
      Left(errorMessage(response, body))
    }

  }

  override def receive: Receive = {
    case query: String => {
      val requester = sender
      var uri = Uri(Settings.autoCompleteURL).withQuery(Query(Map("query" -> query)))

      http.singleRequest(HttpRequest(HttpMethods.GET, uri = uri)).flatMap(response =>
          response.status map handleHttpResponse ) pipeTo requester
    }

  }

Answer 2

您可以使用< code>onComplete函数，该函数将< code>Future[T]作为输入，并返回一个< code>Directive1[Try[T]]，因此您可以按如下方式使用:

pathPrefix("search") {
  get {
    parameter("query") { query =>
      onComplete(restActor.ask(query)) {
        case Success(resp) => ...
        case Failure(e) => ...
      }
    }
  }
}

编辑从您的actor返回的内容，您应该将< code>http.singleRequest的结果通过管道发送给发送方，而不是告诉它:

http.singleRequest(...).flatMap(...) pipeTo requester

这样，只有在未来得到解决后，才会进行实际的告诉（！）。