echos.scala

package example

import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.model.HttpEntity.Chunked
import akka.http.scaladsl.model.{ ContentTypes, HttpRequest, HttpResponse }
import akka.http.scaladsl.server.Directives
import akka.stream.ActorMaterializer
import akka.stream.scaladsl.{ Flow, Tcp }
import akka.util.ByteString

object Example extends App with Directives {

  implicit val sys = ActorSystem()
  implicit val mat = ActorMaterializer()

  // simple TCP echo:
  val echo = Flow[ByteString]
  Tcp().bindAndHandle(echo, "127.0.0.1", 8080)
  // types:
  // echo: Flow[ByteString, ByteString, Unit]


  // low-level Http echo:
  val text = ContentTypes.`text/plain`

  val httpEcho = Flow[HttpRequest].map(r ⇒ HttpResponse(entity = Chunked.fromData(text, r.entity.dataBytes)))
  Http().bindAndHandle(httpEcho, "127.0.0.1", 8081)
  // types:
  // httpEcho: Flow[HttpRequest, HttpResponse, Unit]
  // r.entity.dataBytes: Source[ByteString, Unit]


  // simple Http echo:
  val route = extractRequest { r ⇒
    complete(HttpResponse(entity = Chunked.fromData(text, r.entity.dataBytes)))
  } 
  Http().bindAndHandle(route, "127.0.0.1", 8082)

  readLine()
  sys.shutdown()
  sys.awaitTermination()
}