玩光滑和异步-这是比赛条件吗? [英] Play slick and Async - is it a race condition?

问题描述

阅读

Reading Play-Slick DBAction code, I thought that this code might contain a race condition:

object DBAction{
  // snip

  def apply(r: (RequestWithDbSession) => Result)(implicit app:Application) = {
    Action { implicit request => 
      AsyncResult {
        DB.withSession{ s:scala.slick.session.Session =>
          Future(r( RequestWithDbSession(request,s) ))(executionContext)
      }
    }
  }
}

函数r在withSession返回Future [Result]并称为session.close()之后，将在以后的时间运行.这段代码中是否存在竞争条件?

The function r runs at a future time, after withSession has returned a Future[Result], and called session.close(). Is there a race condition in this code?

推荐答案

我不确定这是否称为竞争条件.但是在我看来，您似乎错了，这是正确的.将来执行代码时，该会话可能不再有效.

I am not sure if that is called a race condition. However to me it seems that you are correct that something is wrong here. The session might no longer be valid when the future executes the code.

最好在将来取消执行并请求数据库会话:

It would be better to invert the execution and request a database session from within the future:

Async {
  Future {
    DB.withSession{ s:scala.slick.session.Session =>
      r( RequestWithDbSession(request, s) )
    }
  }
}

这篇关于玩光滑和异步-这是比赛条件吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！