【SpringCloud学习】Spring Cloud Gateway获取response的值(Greenwich版)

发布日期: 2019-07-21

文章字数: 493

阅读时长: 2 分

阅读次数:

SpringCloudGateway获取、修改客户端请求Request的参数，我们在上一篇已经讲过了。那么网关发起请求后，微服务返回回来的response的值，还是要经过网关才发给客户端的。很多时候，我们希望能看到响应的值，或者修改它，其实很简单

一定要切记接口必须返回标准的json格式不能用string字符串的json格式这样会无法修改的

import com.alibaba.fastjson.JSONObject;
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 ciwei
 */
@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"));
                        JSONObject jsonObject = JSONObject.parseObject(s);
                        jsonObject.put("name" ,"修改name了好不好的呀额");
                        //TODO，s就是response的值，修改、查看都可以
//                        byte[] uppedContent = new String(content, Charset.forName("UTF-8")).getBytes();
                        byte[] uppedContent = jsonObject.toJSONString().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());
    }

}