玩 2.2 EssentialAction 与期货

Question

我正在尝试实现类似于此示例的身份验证机制：

    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，在我的情况下，我将随机令牌值映射到存储在 Mongodb 中的服务器端的会话。目标是能够让用户随意终止他的所有其他会话。

但是，我从 ReactiveMongo 获得的数据将被包装在 Future 中。

我想要这样的东西：

    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 可以做到这一点吗？

Answer 1

Iteratee.flatten 来自 Future[Iteratee[A, E]] => Iteratee[A, E]，所以你可以这样做：

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 作为 invokeBlock 方法返回 Future[SimpleResult] 以便您可以将您的未来平面映射到对底层块的调用

有点像

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()
    }        
}

}

AuthenticatedRequest 是包装会话对象的请求类型