SpringCloud gateway如何修改返回数据

版本说明

开源软件	版本
springboot	2.1.6.RELEASE
jdk	11.0.3

gradle

主要引入了springboot 2.1,lombok

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									plugins {

									    id 'org.springframework.boot' version '2.1.6.RELEASE'

									    id 'java'

									    id "io.freefair.lombok" version "3.6.6"

									}apply plugin: 'io.spring.dependency-management'group = 'cn.buddie.demo'

									version = '0.0.1-SNAPSHOT'

									sourceCompatibility = '11'repositories {

									    mavenCentral()

									}ext {

									    set('springCloudVersion', "Greenwich.SR2")

									}dependencies {

									    implementation 'org.springframework.cloud:spring-cloud-starter-gateway'

									    compile 'org.projectlombok:lombok:1.18.8'

									    testImplementation 'org.springframework.boot:spring-boot-starter-test'

									}dependencyManagement {

									    imports {

									        mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"

									    }

									}

yaml

定义路由及过滤器 test-route路由，当Path为/users时，转到uri中配置的链接http://127.0.0.1:8123/users中。使用UnionResult来过滤

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									spring:

									  cloud:

									    gateway:

									      enabled: true

									      routes:

									      - id: test-route

									        uri: http://127.0.0.1:8123/users

									        predicates:

									        - Path=/users

									        filters:

									        - UnionResult

filter

yaml中配置的filter名字，加“GatewayFilterFactory”,就是对应的过滤器Java类

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									package cn.buddie.demo.springcloudgateway.filter;import cn.buddie.demo.springcloudgateway.model.UnionResult;

									import org.springframework.cloud.gateway.filter.GatewayFilter;

									import org.springframework.cloud.gateway.filter.factory.rewrite.ModifyResponseBodyGatewayFilterFactory;

									import org.springframework.cloud.gateway.filter.factory.rewrite.RewriteFunction;

									import org.springframework.stereotype.Component;

									import reactor.core.publisher.Mono;/**

									 * description

									 *

									 * @author buddie.wei

									 * @date 2019/7/20

									 */

									@Component

									public class UnionResultGatewayFilterFactory extends ModifyResponseBodyGatewayFilterFactory {

									    @Override

									    public GatewayFilter apply(Config config) {

									        return new ModifyResponseGatewayFilter(this.getConfig());

									    }

									    private Config getConfig() {

									        Config cf = new Config();

									        // Config.setRewriteFunction(Class<T> inClass, Class<R> outClass, RewriteFunction<T, R> rewriteFunction)

									        // inClass 原数据类型，可以指定为具体数据类型，我这里指定为Object,是为了处理多种数据类型。

									        //                      当然支持多接口返回多数据类型的统一修改，yaml中的配置，path,uri需要做相关调整

									        // outClass 目标数据类型

									        // rewriteFunction 内容重写方法

									        cf.setRewriteFunction(Object.class, UnionResult.class, getRewriteFunction());

									        return cf;

									    }    private RewriteFunction<Object, UnionResult> getRewriteFunction() {

									        return (exchange, resp) -> Mono.just(UnionResult.builder().requestId(exchange.getRequest().getHeaders().getFirst("cn-buddie.demo.requestId")).result(resp).build());

									    }

									}

model

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									package cn.buddie.demo.springcloudgateway.model;import lombok.Builder;

									import lombok.Getter;

									import lombok.Setter;/**

									 * description

									 *

									 * @author buddie.wei

									 * @date 2019/7/20

									 */

									@Getter

									@Setter

									@Builder

									public class UnionResult {

									    private String requestId;

									    private Object result;

									}

SpringCloud gateway修改返回的响应体

问题描述：

在gateway中修改返回的响应体，在全局Filter中添加如下代码：

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									import org.springframework.core.Ordered;

									import org.springframework.cloud.gateway.filter.GlobalFilter;

									import org.springframework.cloud.gateway.filter.GatewayFilterChain;

									import org.springframework.stereotype.Component;

									import org.springframework.web.server.ServerWebExchange;

									import reactor.core.publisher.Mono;@Component

									public class RequestGlobalFilter implements GlobalFilter, Ordered {

									 //...

									 @Override

									 public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {

									  //...

									  ResponseDecorator decorator = new ResponseDecorator(exchange.getResponse());

									  return chain.filter(exchange.mutate().response(decorator).build());

									 } @Override

									 public int getOrder() {

									  return -1000;

									 }

									}

通过.response(decorator)设置一个响应装饰器（自定义），以下是装饰器具体实现：

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									import cn.hutool.json.JSONObject;

									import org.reactivestreams.Publisher;

									import org.springframework.core.io.buffer.DataBuffer;

									import org.springframework.core.io.buffer.DataBufferFactory;

									import org.springframework.core.io.buffer.DataBufferUtils;

									import org.springframework.core.io.buffer.DefaultDataBufferFactory;

									import org.springframework.http.server.reactive.ServerHttpResponse;

									import org.springframework.http.server.reactive.ServerHttpResponseDecorator;

									import reactor.core.publisher.Flux;

									import reactor.core.publisher.Mono;

									import java.nio.charset.Charset;/**

									 * @author visy.wang

									 * @desc 响应装饰器（重构响应体）

									 */

									public class ResponseDecorator extends ServerHttpResponseDecorator{

									 public ResponseDecorator(ServerHttpResponse delegate){

									  super(delegate);

									 } @Override

									 @SuppressWarnings(value = "unchecked")

									 public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {  if(body instanceof Flux) {

									   Flux<DataBuffer> fluxBody = (Flux<DataBuffer>) body;   return super.writeWith(fluxBody.buffer().map(dataBuffers -> {

									    DataBufferFactory dataBufferFactory = new DefaultDataBufferFactory();

									    DataBuffer join = dataBufferFactory.join(dataBuffers);    byte[] content = new byte[join.readableByteCount()];

									    join.read(content);

									    DataBufferUtils.release(join);// 释放掉内存

									    String bodyStr = new String(content, Charset.forName("UTF-8"));                //修改响应体

									    bodyStr = modifyBody(bodyStr);    getDelegate().getHeaders().setContentLength(bodyStr.getBytes().length);

									    return bufferFactory().wrap(bodyStr.getBytes());

									   }));

									  }

									  return super.writeWith(body);

									 }    //重写这个函数即可

									 private String modifyBody(String jsonStr){

									  JSONObject json = new JSONObject(jsonStr);

									        //TODO...修改响应体

									  return json.toString();

									 }

									}