Akka HTTP WebSocket example using high-level routing DSL

HighLevelWebSocketSample.scala

package com.tutorial.sample

import akka.http.scaladsl.model.ws.{Message, TextMessage}
import akka.http.scaladsl.server.Directives
import akka.stream.scaladsl.{Flow, Source}

trait HighLevelWebSocketSample extends Directives {

  def route =
    path("chat") {
      parameter('name) { name ⇒
        handleWebSocketMessages(broadcast(name))
      }
    }

  def broadcast(name: String): Flow[Message, Message, Any] = {
    Flow[Message].mapConcat {
      case tm: TextMessage =>
        TextMessage(Source.single(name + "::") ++ tm.textStream) :: Nil
    }
  }

}

import akka.http.scaladsl.testkit.{ScalatestRouteTest, WSProbe}
import org.scalatest.{Matchers, WordSpec}

class HighLevelWebSocketSampleTest extends WordSpec with Matchers with ScalatestRouteTest with HighLevelWebSocketSample{

  "Websocket" should {
    "be able to pull and push message" in {
      val wsClient = WSProbe()
      WS("/chat?name=Chris", wsClient.flow) ~> route ~>
        check {
          isWebSocketUpgrade shouldEqual true

          wsClient.sendMessage("How are you?")
          wsClient.expectMessage("Chris::How are you?")
        }
    }
  }
}