SpringCloud gateway How to Modify Returned Data
- 2021-10-15 10:43:02
- OfStack
Version description
开源软件 | 版本 |
---|---|
springboot | 2.1.6.RELEASE |
jdk | 11.0.3 |
gradle
springboot 2.1 and lombok are mainly introduced
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
Define the route and filter test-route route. When Path is/users, go to the link http://127.0.0.1: 8123/users configured in uri. Use UnionResult to filter
spring:
cloud:
gateway:
enabled: true
routes:
- id: test-route
uri: http://127.0.0.1:8123/users
predicates:
- Path=/users
filters:
- UnionResult
filter
The name of filter configured in yaml, plus "GatewayFilterFactory", is the corresponding filter Java class
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 The original data type can be specified as a specific data type, which I specify here as Object, Is to deal with multiple data types.
// Of course, it supports multi-interface to return multi-data type system 1 Modify, yaml Configuration in, path,uri Need to make relevant adjustments
// outClass Target data type
// rewriteFunction Content rewriting method
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
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 Modify the returned response body
Problem description:
Modify the returned response body in gateway and add the following code in the global Filter:
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;
}
}
Set up a response decorator (custom) via. response (decorator), and the following is the concrete implementation of the decorator:
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 Response decorator (reconstruct response body)
*/
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);// Release memory
String bodyStr = new String(content, Charset.forName("UTF-8")); // Modify the response body
bodyStr = modifyBody(bodyStr); getDelegate().getHeaders().setContentLength(bodyStr.getBytes().length);
return bufferFactory().wrap(bodyStr.getBytes());
}));
}
return super.writeWith(body);
} // You can override this function
private String modifyBody(String jsonStr){
JSONObject json = new JSONObject(jsonStr);
//TODO... Modify the response body
return json.toString();
}
}