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春季-有效的路由


十字路口的骑士Victor Vasnetsov；fatcatart.com


哈Ha！这里简要介绍了GitHub的一个有趣的错误。有关回放，请参见spring-flux-callstack项目。


不久前，我注意到由于应用程序错误，堆栈跟踪有时会很长。并在其中重复了相同的行多次（堆栈在切割下跟踪自身）：


at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
at reactor.core.publisher.Operators.complete(Operators.java:135)
at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
at reactor.core.publisher.Mono.subscribe(Mono.java:4110)

, Project Reactor, Router Function WebFlux.


, , . .


at org.springframework.web.reactive.function.server.CoRouterFunctionDsl$asHandlerFunction$1$1.invokeSuspend(CoRouterFunctionDsl.kt:599)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
    at kotlinx.coroutines.DispatchedContinuationKt.resumeCancellableWith(DispatchedContinuation.kt:313)
    at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable(Cancellable.kt:26)
    at kotlinx.coroutines.CoroutineStart.invoke(CoroutineStart.kt:109)
    at kotlinx.coroutines.AbstractCoroutine.start(AbstractCoroutine.kt:158)
    at kotlinx.coroutines.reactor.MonoKt$monoInternal$1.accept(Mono.kt:55)
    at kotlinx.coroutines.reactor.MonoKt$monoInternal$1.accept(Mono.kt)
    at reactor.core.publisher.MonoCreate.subscribe(MonoCreate.java:57)
    at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
    at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:150)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:76)
    at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:274)
    at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:851)
    at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114)
    at reactor.core.publisher.FluxPeek$PeekSubscriber.onNext(FluxPeek.java:192)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:67)
    at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2267)
    at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2075)
    at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:1949)
    at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:54)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:78)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:75)
    at reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:136)
    at reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:136)
    at reactor.core.publisher.Operators.complete(Operators.java:135)
    at reactor.core.publisher.MonoEmpty.subscribe(MonoEmpty.java:45)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:441)
    at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onSubscribe(FluxConcatMap.java:211)
    at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:161)
    at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:86)
    at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
    at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:52)
    at reactor.core.publisher.Mono.subscribe(Mono.java:4110)
    at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:172)
    at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56)
    at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:55)
    at reactor.netty.http.server.HttpServerHandle.onStateChange(HttpServerHandle.java:64)
    at reactor.netty.tcp.TcpServerBind$ChildObserver.onStateChange(TcpServerBind.java:228)
    at reactor.netty.http.server.HttpServerOperations.onInboundNext(HttpServerOperations.java:465)
    at reactor.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:90)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
    at reactor.netty.http.server.HttpTrafficHandler.channelRead(HttpTrafficHandler.java:170)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
    at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:436)
    at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:321)
    at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:295)
    at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:251)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
    at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
    at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
    at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
    at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
    at io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:792)
    at io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe$1.run(AbstractEpollChannel.java:387)
    at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
    at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
    at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:384)
    at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
    at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.base/java.lang.Thread.run(Thread.java:834)

Router Function


, Router Function. API, Spring Framework v5, :


@Bean
open fun httpEndpoints(): RouterFunction<ServerResponse> {
    return coRouter {
        GET("/api/users") {
            ServerResponse
                    .ok()
                    .bodyValueAndAwait("Ok !!!!")
        }
        GET("/api/developers") {
            ServerResponse
                    .badRequest()
                    .bodyValueAndAwait("Not ok (((")
        }
    }
}

GET suspend (ServerRequest) -> ServerResponse, ServerRequest ServerResponse. . , - , ( ):


@Bean
open fun httpEndpoints(): RouterFunction<ServerResponse> {
    //   -    
    val urlToMethod: Map<String, RequestProcessor> = createRequestProcessors()
    return coRouter {
        urlToMethod.forEach { url, processor -> // forEach   
            GET("/$url") {
                processor.createResponse(it)
            }
        }
    }
}

, API , ( ). , .


Router Function?


RouterFunction , :


@FunctionalInterface
public interface RouterFunction<T extends ServerResponse> {
    Mono<HandlerFunction<T>> route(ServerRequest request);

    default RouterFunction<T> and(RouterFunction<T> other) {
        return new RouterFunctions.SameComposedRouterFunction<>(this, other);
    }

    default RouterFunction<?> andOther(RouterFunction<?> other) {
        return new RouterFunctions.DifferentComposedRouterFunction(this, other);
    }

    default RouterFunction<T> andRoute(RequestPredicate predicate, HandlerFunction<T> handlerFunction) {
        return and(RouterFunctions.route(predicate, handlerFunction));
    }

    default RouterFunction<T> andNest(RequestPredicate predicate, RouterFunction<T> routerFunction) {
        return and(RouterFunctions.nest(predicate, routerFunction));
    }

    default <S extends ServerResponse> RouterFunction<S> filter(HandlerFilterFunction<T, S> filterFunction) {
        return new RouterFunctions.FilteredRouterFunction<>(this, filterFunction);
    }

    default void accept(RouterFunctions.Visitor visitor) {
        visitor.unknown(this);
    }
}

, url. , :


  2. ( )
  3. , Mono.empty(), " url ".

, , . -, , URL (.. ). , , ( GET, ), ( , , ..).


:


@Bean
open fun httpEndpoints(): RouterFunction<ServerResponse> {
    //   -    
    val urlToMethod: Map<String, RequestProcessor> = createRequestProcessors()
    return coRouter {
        urlToMethod.forEach { url, processor -> // forEach   
            GET("/$url") {
                processor.createResponse(it)
            }
        }
    }
}

, , GET RouterFunction. , URL ( ), . , . , N, O(N*M*K), M — , K — RouterFunction ( , , , , switch Java ). , ( ), .


, (, -, ), . , , web . , , O(min(M, N)), N — , M — , .


?


1: pattern. , /[static-prefix]/[suffix], static-prefix , :


GET("/static-prefix/{suffix}"), 
      req -> ok().body(
          execute(
              req.pathVariable("suffix")
          )
        )

. switch , (, Java/Kotlin/Scala switch , , ).


2: . :


public RouterFunction<ServerResponse> productSearch(ProductService ps) {
    return route().nest(
        RequestPredicates.path("/product"), 
        builder -> { //       
                builder.GET("/name/{name}", req -> ok().body(ps.findByName(req.pathVariable("name"))));
            }
        ).build();
}

...


: - , . , . , .


如您所见，由于抽象和可扩展性的思想，您不应该依赖Spring团队会神奇地加快处理速度这一事实。最好只是简化配置。

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