StackableController + Slick + PlayFramework で暗黙的にDBSession使いまわすのやつメモ

gistfile1.scala

trait SlickDBSessionElement extends StackableController {
  self: Controller =>

  import play.api.db.slick
  type Session = slick.Session

  case object DBSessionKey extends RequestAttributeKey[Session]

  override def proceed[A](req: RequestWithAttributes[A])(f: RequestWithAttributes[A] => Result): Result = {
    val session:Session = play.api.db.slick.DB.createSession()
    super.proceed(req.set(DBSessionKey, session))(f)
  }

  override def cleanupOnSucceeded[A](req: RequestWithAttributes[A]): Unit = {
    try {
      req.get(DBSessionKey).map(_.close())
    } finally {
      super.cleanupOnSucceeded(req)
    }
  }

  override def cleanupOnFailed[A](req: RequestWithAttributes[A], e: Exception): Unit = {
    try {
      req.get(DBSessionKey).map(_.close())
    } finally {
      super.cleanupOnFailed(req, e)
    }
  }

  implicit def dbSession(implicit req: RequestWithAttributes[_]): Session = req.get(DBSessionKey).get

  def withTransaction[T](f: => T)(implicit req: RequestWithAttributes[_]): T = {
    slick.DB("master").withTransaction(f)
  }
}