Spring响应式应用程序上的请求/响应正文的副本？

Question

我正在研究访问HTTP请求和响应主体的最佳方法,以便在Spring反应式应用程序中进行跟踪.

对于以前的版本,我们利用Servlet过滤器和Servlet请求包装器来使用传入请求的输入流并保存它的副本以进行跟踪的异步处理(我们将它们发送到Elasticsearch).

但是对于一个Spring响应式应用程序(使用webflux),我想知道在解码之前访问请求的最合适方式是什么.有什么想法吗？

Answer 1

原来,这可以通过提供可实现装饰:ServerWebExchangeDecorator,ServerHttpRequestDecorator和ServerHttpResponseDecorator分别.

这是一个示例请求装饰器,它将DataBuffer内容累积为请求的默认订阅者读取的内容:

@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();
    }

只需确保当你装饰ServerWebExchange传递的时候WebFilter,你也会覆盖getRequest()以返回请求装饰器:

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(注意静态导入的功能):

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