HttpServer.scala

package reactive5

import akka.actor.typed.ActorSystem
import akka.actor.typed.scaladsl.Behaviors
import akka.http.scaladsl.Http
import akka.http.scaladsl.model._
import akka.http.scaladsl.server.Directives._
import scala.io.StdIn
import com.typesafe.config.ConfigFactory

// see: https://doc.akka.io/docs/akka-http/current/routing-dsl/index.html#minimal-example
object HttpServer extends App {
  implicit val system =
    ActorSystem(Behaviors.empty[Any], "reactive5", ConfigFactory.empty())
  // needed for the future flatMap/onComplete in the end
  implicit val executionContext = system.executionContext

  val route =
    path("hello") {
      get {
        complete(
          HttpEntity(
            ContentTypes.`text/html(UTF-8)`,
            "<h1>Say hello to akka-http</h1>"
          )
        )
      }
    }

  val bindingFuture = Http().newServerAt("localhost", 8080).bind(route)

  println(
    s"Server now online. Please navigate to http://localhost:8080/hello\nPress RETURN to stop..."
  )
  StdIn.readLine() // let it run until user presses return
  bindingFuture
    .flatMap(_.unbind()) // trigger unbinding from the port
    .onComplete(_ => system.terminate()) // and shutdown when done
}