playing with websockets using akka-http / published by https://github.com/dacr/code-examples-manager #50673e88-dcb8-4a43-8c40-46d82d30ae50/3588e65805b4fe702465e07bbf898924ed3b1138

akka-http-client-websocket-hello-world.sc

// summary : playing with websockets using akka-http
// keywords : scala, actors, akka, http-client, client, json, json4s, websocket, helloworld
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : 50673e88-dcb8-4a43-8c40-46d82d30ae50
// created-on : 2021-02-05T18:06:03Z
// managed-by : https://github.com/dacr/code-examples-manager
// execution : scala ammonite script (http://ammonite.io/) - run as follow 'amm scriptname.sc'

import $ivy.`com.typesafe.akka::akka-http:10.2.4`
import $ivy.`com.typesafe.akka::akka-stream-typed:2.6.13`
import akka.Done
import akka.http.scaladsl._
import akka.http.scaladsl.model.StatusCodes
import akka.http.scaladsl.model.ws.{Message, TextMessage, WebSocketRequest}
import akka.stream.scaladsl.{Keep, Sink, Source}

import scala.concurrent._
import scala.concurrent.duration._


object TestThat {
  implicit val system = akka.actor.ActorSystem("MySystem")
  implicit val executionContext = system.dispatcher

  //val outgoing = Source.single(TextMessage("hello world!"))
  val outgoing = Source.fromIterator( () =>
    List(
      "Hello world :)",
      "What's your name ?",
      "Shut up your face !"
    ).to(Iterator).map(s => TextMessage(s))
  )

  val incoming: Sink[Message, Future[Done]] =
    Sink.foreach[Message] {
      case message: TextMessage.Strict => println(message.text)
      case _ =>
    }

  val uri = s"ws://echo.websocket.org"
  val flow = Http().webSocketClientFlow(WebSocketRequest(uri = uri))

  val (upgradedResponse, closed) =
    outgoing
      .viaMat(flow)(Keep.right)
      .toMat(incoming)(Keep.both)
      .run()

  val connected = upgradedResponse.flatMap { upgrade =>
    if (upgrade.response.status == StatusCodes.SwitchingProtocols) {
      Future.successful(Done)
    } else {
      throw new RuntimeException(s"Connection failed: ${upgrade.response.status}")
    }
  }

  // Do not exit before the future has completed ;)
  def andWait():Unit = Await.ready(closed, 10.seconds)

}

TestThat.andWait()