spring gateway 截取response 长度缺失

网上找到一段获取修改response的代码：https://blog.csdn.net/tianyaleixiaowu/article/details/83618037

代码如下：

import org.reactivestreams.Publisher;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
 
import java.nio.charset.Charset;
 
/**
 * @author wuweifeng wrote on 2018/10/31.
 */
@Component
public class WrapperResponseGlobalFilter implements GlobalFilter, Ordered {
    @Override
    public int getOrder() {
        // -1 is response write filter, must be called before that
        return -2;
    }
 
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpResponse originalResponse = exchange.getResponse();
        DataBufferFactory bufferFactory = originalResponse.bufferFactory();
        ServerHttpResponseDecorator decoratedResponse = new ServerHttpResponseDecorator(originalResponse) {
            @Override
            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
                if (body instanceof Flux) {
                    Flux<? extends DataBuffer> fluxBody = (Flux<? extends DataBuffer>) body;
                    return super.writeWith(fluxBody.map(dataBuffer -> {
                        // probably should reuse buffers
                        byte[] content = new byte[dataBuffer.readableByteCount()];
                        dataBuffer.read(content);
                        //释放掉内存
                        DataBufferUtils.release(dataBuffer);
                        String s = new String(content, Charset.forName("UTF-8"));
                        //TODO，s就是response的值，想修改、查看就随意而为了
                        byte[] uppedContent = new String(content, Charset.forName("UTF-8")).getBytes();
                        return bufferFactory.wrap(uppedContent);
                    }));
                }
                // if body is not a flux. never got there.
                return super.writeWith(body);
            }
        };
        // replace response with decorator
        return chain.filter(exchange.mutate().response(decoratedResponse).build());
    }
}

实践后发现，在多次测试或者压力测试时，会间歇性出现问题。

问题在这里

  public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
                if (body instanceof Flux) {
                    Flux<? extends DataBuffer> fluxBody = (Flux<? extends DataBuffer>) body;
                    return super.writeWith(fluxBody.map(dataBuffer -> {
                        // probably should reuse buffers
                        byte[] content = new byte[dataBuffer.readableByteCount()];

这段代码中，重写了response的构造方法，将body映射为需要的byte[]以便于后面操作

但是这里的dataBuffer经常取到的长度低于实际长度，丢失了内容。

还没找到内容，先换一种方法实现，待续...