TcpServerOneResponseThenComplete.scala

import akka.actor.ActorSystem
import akka.stream.scaladsl.Flow
import akka.stream.scaladsl.Tcp
import akka.util.ByteString

object TcpServerOneResponseThenComplete {

  def main(args: Array[String]): Unit = {
    implicit val system = ActorSystem()
    import akka.stream.scaladsl.Framing

    val framing = Framing.delimiter(ByteString("\n"), 1024)

    Tcp().bind("127.0.0.1", 9999).runForeach { incomingConnection =>
      incomingConnection.handleWith(Flow[ByteString]
        .via(framing)
      .prefixAndTail(1)
      .map { case (Seq(firstFrame), rest) =>
        println(s"Request: ${firstFrame.utf8String}")
        rest.run()
        ByteString("Response\n")
      }.take(1))
    }

  }

}