Ktor 拦截器中的状态答案

【问题标题】：State in Ktor InterceptersKtor 拦截器中的状态
【发布时间】：2018-10-15 09:35:49
【问题描述】：

我正在按照此帮助页面上的说明进行操作：https://ktor.io/advanced/pipeline/route.html

他们举了这个例子：

fun Route.routeTimeout(time: Long, unit: TimeUnit = TimeUnit.SECONDS, callback: Route.() -> Unit): Route {
    // With createChild, we create a child node for this received Route  
    val routeWithTimeout = this.createChild(object : RouteSelector(1.0) {
        override fun evaluate(context: RoutingResolveContext, segmentIndex: Int): RouteSelectorEvaluation =
            RouteSelectorEvaluation.Constant
    })

    // Intercepts calls from this route at the features step
    routeWithTimeout.intercept(ApplicationCallPipeline.Features) {
        withTimeout(time, unit) {
            proceed() // With proceed we can define code to be executed before and after the call
        }
    }

    // Configure this route with the block provided by the user
    callback(routeWithTimeout)

    return routeWithTimeout
}

我想修改它，以便它可以保持状态。例如，每个下一个调用者都会获得更大的超时。我在哪里放置我的状态？

【问题讨论】：

标签： kotlin ktor

【解决方案1】：

您可以将状态保持在周围的闭包中。我通过增加超时来扩展您的示例：

fun Route.routeTimeout(time: Long, unit: TimeUnit = TimeUnit.SECONDS, callback: Route.() -> Unit): Route {
    // With createChild, we create a child node for this received Route
    val routeWithTimeout = this.createChild(object : RouteSelector(1.0) {
        override fun evaluate(context: RoutingResolveContext, segmentIndex: Int): RouteSelectorEvaluation =
            RouteSelectorEvaluation.Constant
    })

    // state
    var newTime = time

    // Intercepts calls from this route at the features step
    routeWithTimeout.intercept(ApplicationCallPipeline.Features) {
        try{
            withTimeout(newTime, unit) {
                proceed() // With proceed we can define code to be executed before and after the call
            }
        } catch (e: TimeoutCancellationException) {
            // change the state
            newTime*=2
            throw e
        }
    }

    // Configure this route with the block provided by the user
    callback(routeWithTimeout)

    return routeWithTimeout
}

【讨论】：