Scala-Play-Slick-Demo/app/controllers/HomeController.scala

package controllers

import javax.inject.{Inject, Singleton}

import com.example.user.UserDAO
import play.api.mvc._

import scala.concurrent.ExecutionContext
import com.example.user.CarDAO
import com.example.services.LibraryService
import play.api.libs.json.Json

@Singleton
class HomeController @Inject() (userDAO: UserDAO, carDAO: CarDAO, libraryService: LibraryService, cc: ControllerComponents)
                               (implicit ec: ExecutionContext)
  extends AbstractController(cc) {

  def index = Action.async { implicit request =>
    userDAO.all.map { users =>
      Ok(views.html.index(users))
    }
  }

  def cars = Action.async { implicit request =>
    carDAO.all.map { cars =>
      Ok(views.html.cars(cars))
    }
  }

  def book = Action.async{
    // libraryService.findBookById(1).map(e => Ok(Json.toJson(e)))
    // libraryService.insertBookAndAuthor(Book("new book"), Author(2, "Some retard"))

    for {
      maybeBook <- libraryService.findBookById(1)
    } yield (Ok(Json.toJson(maybeBook)))
  }

}