Rack-like middleware for Play actions

gistfile1.scala

object Middleware {

  def stack[A](middlewares: Middleware[A]*) = {
    middlewares.toSeq.reduceLeft[Action[A]] { (result, middleware)
      middleware(result)
    }
  }

}

trait Middleware[A] {

  def apply(action: Action[A]): Action[A]

}

object Logger[A] extends Middleware[A] {

  def apply(action: Action[A]) = Action.async(action.parser) { request =>
    Logger.info("Logging this, like, right now.")
    action(request)
  }

}

object Timer[A] extends Middleware[A] {

  def apply(action: Action[A]) = Action.async(action.parser) { request =>
    val start = System.currentTimeMillis
    val result = action(request)
    val duration = System.currentTimeMillis - start
    result.withHeaders("X-Request-Time" -> duration)
  }

}

Middleware.stack(
  Logger,
  Timer
)