Question

我正在使用akka-http websocket客户端连接websocket服务器以及发送和检索消息。

object WebSocketClientFlow {
def main(args: Array[String]) = {
implicit val system = ActorSystem()
implicit val materializer = ActorMaterializer()
import system.dispatcher

// Future[Done] is the materialized value of Sink.foreach,
// emitted when the stream completes
val incoming: Sink[Message, Future[Done]] =
  Sink.foreach[Message] {
    case message: TextMessage.Strict =>
      println(message.text)
  }

// send this as a message over the WebSocket
val outgoing = Source.single(TextMessage("hello world!"))

// flow to use (note: not re-usable!)
val webSocketFlow = Http().webSocketClientFlow(WebSocketRequest("ws://echo.websocket.org"))

// the materialized value is a tuple with
// upgradeResponse is a Future[WebSocketUpgradeResponse] that
// completes or fails when the connection succeeds or fails
// and closed is a Future[Done] with the stream completion from the incoming sink
val (upgradeResponse, closed) =
  outgoing
    .viaMat(webSocketFlow)(Keep.right) // keep the materialized Future[WebSocketUpgradeResponse]
    .toMat(incoming)(Keep.both) // also keep the Future[Done]
    .run()

// just like a regular http request we can access response status which is available via upgrade.response.status
// status code 101 (Switching Protocols) indicates that server support WebSockets
val connected = upgradeResponse.flatMap { upgrade =>
  if (upgrade.response.status == StatusCodes.SwitchingProtocols) {
    Future.successful(Done)
  } else {
    throw new RuntimeException(s"Connection failed: ${upgrade.response.status}")
  }
}

// in a real application you would not side effect here
connected.onComplete(println)
closed.foreach(_ => println("closed"))
}
}

akka-http文档中提到了此示例。

使用此示例，我只能向请求发送一条消息。如何在同一请求上发送和检索多条消息？

Answer 1

您需要查看文档的半封闭套接字部分。

http://doc.akka.io/docs/akka/2.4.10/scala/http/client-side/websocket-support.html#Half-Closed_WebSockets

基本上，将Source.maybe打到您的传出流（通常是订阅消息），它会阻止套接字关闭。

使用Akka-Http无法使用相同的websocket连接发送多条消息

1 个答案: