玩2.2 EssentialAction與期貨

Question

我正在嘗試實現類似於此示例的身份驗證機制：

    def HasToken(action: String => EssentialAction): EssentialAction = EssentialAction { requestHeader =>
      val maybeToken = requestHeader.headers.get("X-SECRET-TOKEN")
      maybeToken map { token =>
        action(token)(requestHeader) // apply requestHeader to EssentialAction produces the Iteratee[Array[Byte], SimpleResult]
      } getOrElse {
        Done(Unauthorized("401 No Security Token\n")) // 'Done' means the Iteratee has completed its computations
      }
    }

但是，就我而言，我正在將隨機令牌值映射到存儲在Mongodb中的服務器端的會話。 目的是使用戶可以隨意終止所有其他會話。

但是，我將從ReactiveMongo獲得的數據包裝在Future中。

我想要這樣的東西：

    def HasToken(action: String => EssentialAction): EssentialAction = EssentialAction { requestHeader =>
      val maybeToken = requestHeader.headers.get("session")
      maybeToken map { token =>
        //This returns a future..
        Session.find(session).map { result => 
          result match
            case Some(session) => action(session)(requestHeader)
            case None => Done(Unauthorized())
        }
      } getOrElse {
        Done(Unauthorized("401 No Security Token\n")) // 'Done' means the Iteratee has completed its computations
      }
    }

EssentialAction是否可能？

Answer 1

Iteratee.flatten來自Future[Iteratee[A, E]] => Iteratee[A, E]因此您可以這樣操作：

def HasToken(action: String => EssentialAction): EssentialAction = EssentialAction { requestHeader =>
   val maybeToken = requestHeader.headers.get("session")

   val futureIteratee: Future[Iteratee[Array[Byte], SimpleResult]] = maybeToken map { token =>
     //This returns a future..
     Session.find(token).map {
       case Some(session) => action(session)(requestHeader)
       case None => Done[Array[Byte], SimpleResult](Unauthorized("Invalid token"))
     }
   } getOrElse {
     Future.successful(Done[Array[Byte], SimpleResult](Unauthorized("401 No Security Token\n")))
   }

   Iteratee.flatten(futureIteratee)
}

Answer 2

您可以使用ActionBuilder作為invokeBlock方法返回Future [SimpleResult]，以便可以將Future映射到對基礎塊的調用中

就像是

object Authenticated extends ActionBuilder[AuthenticatedRequest] {
  def invokeBlock[A](request: Request[A], block: (AuthenticatedRequest[A]) => Future[SimpleResult]) = {
    Session.find(session).map { result => 
      result match
        case Some(session) => block(new AuthenticatedRequest(session))
        case None => Unauthorized()
    }        
}

}

其中AuthenticatedRequest是包裝會話對象的請求類型