Akka-Http-Post.scala

trait RestService {
 
  implicit val userFormat = jsonFormat2(User)
  val userImpl: UserImpl

  val route =
    post {
      path("adduser") {
        entity(as[User]) { user =>
          val saved: Future[Done] = userImpl.addUser(user)
          onComplete(saved) { _ =>
            complete("user added")
          }
        }
      }
    } 
 
}

class RestServiceImpl extends RestService {
  val userImpl = UserImpl
}