Spring Reactive应用程序上的请求/响应正文的副本？

我正在研究访问HTTP请求和响应正文的最佳方法，以便在Spring反应性应用程序中进行跟踪。

对于以前的版本，我们利用Servlet筛选器和Servlet请求包装器来使用传入请求的输入流，并保留它的副本以用于跟踪的异步处理(我们将它们发送到Elasticearch)。

但是对于一个Spring Reactive应用程序(使用WebFlux)，我想知道在请求被解码之前访问它们的最合适的方式是什么。有什么想法吗？

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解决方案

事实证明，这可以使用提供的修饰符分别实现：ServerWebExchangeDecorator、ServerHttpRequestDecorator和ServerHttpResponseDecorator。

下面是一个示例请求修饰符，它在请求的默认订阅者读取内容时累积DataBuffer内容：

@Slf4j
public class CachingServerHttpRequestDecorator extends ServerHttpRequestDecorator {

    @Getter
    private final OffsetDateTime timestamp = OffsetDateTime.now();
    private final StringBuilder cachedBody = new StringBuilder();

    CachingServerHttpRequestDecorator(ServerHttpRequest delegate) {
        super(delegate);
    }

    @Override
    public Flux<DataBuffer> getBody() {
        return super.getBody().doOnNext(this::cache);
    }

    @SneakyThrows
    private void cache(DataBuffer buffer) {
        cachedBody.append(UTF_8.decode(buffer.asByteBuffer())
         .toString());
    }

    public String getCachedBody() {
        return cachedBody.toString();
    }

只需确保在修饰WebFilter传递的ServerWebExchange时，也重写getRequest()以返回请求修饰符：

public final class PartnerServerWebExchangeDecorator extends ServerWebExchangeDecorator {

    private final ServerHttpRequestDecorator requestDecorator;
    private final ServerHttpResponseDecorator responseDecorator;

    public PartnerServerWebExchangeDecorator(ServerWebExchange delegate) {
        super(delegate);
        this.requestDecorator = new PartnerServerHttpRequestDecorator(delegate.getRequest());
        this.responseDecorator = new PartnerServerHttpResponseDecorator(delegate.getResponse());
    }

    @Override
    public ServerHttpRequest getRequest() {
        return requestDecorator;
    }

    @Override
    public ServerHttpResponse getResponse() {
        return responseDecorator;
    }

}

在过滤器上：

@Component
public class TracingFilter implements WebFilter {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
        return chain.filter(new PartnerServerWebExchangeDecorator(exchange));
    }
}

可以这样使用的函数(注意静态导入的函数)：

@Bean
public HttpHandler myRoute(MyHandler handler) {
    final RouterFunction<ServerResponse> routerFunction =
        route(POST("/myResource"), handler::persistNotification);
    return webHandler(toWebHandler(routerFunction))
        .filter(new TracingFilter())
        .build();
}