介绍
Spring Cloud Gateway（以下简称 SCG）做为网关服务，是其他各服务对外中转站，通过 SCG 进行请求转发。
在请求到达真正的微服务之前，我们可以在这里做一些预处理，比如：来源合法性检测，权限校验，反爬虫之类…
因为业务需要，我们的服务的请求参数都是经过加密的。
之前是在各个微服务的拦截器里对来解密验证的，现在既然有了网关，自然而然想把这一步骤放到网关层来统一解决。
参考：https://windmt.com/2019/01/16/spring-cloud-19-spring-cloud-gateway-read-and-modify-request-body/
本文使用的版本：
- Spring Cloud: Greenwich.RELEASE
- Spring Boot: 2.1.3.RELEASE
如果了解的 GatewayFilterFactory 和 GatewayFilter 的关系的话，不用我说你就知道该怎么办了。不知道也没关系，我们把 ModifyRequestBodyGatewayFilterFactory 中红框部分 copy 出来，粘贴到我们之前创建的 ValidateFilter#filter 中
我们稍作修改，即可实现读取并修改 Request Body 的功能了（核心部分见上图黄色箭头处）
废话不多说 直接上代码
import com.alibaba.fastjson.JSONObject;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.cloud.gateway.support.BodyInserterContext;
import org.springframework.cloud.gateway.support.CachedBodyOutputMessage;
import org.springframework.cloud.gateway.support.DefaultServerRequest;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.stereotype.Component;
import org.springframework.web.reactive.function.BodyInserter;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Collectors;
@Component
public class ValidateFilter implements GlobalFilter, Ordered {
@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
ServerRequest serverRequest = new DefaultServerRequest(exchange);
// mediaType
MediaType mediaType = exchange.getRequest().getHeaders().getContentType();
Mono<JSONObject> modifiedBodyJson = null;
Mono<String> modifiedBodyString = null;
BodyInserter bodyInserter = null;
//JSON请求
if (MediaType.APPLICATION_JSON.isCompatibleWith(mediaType)) {
// read & modify body
modifiedBodyJson = serverRequest.bodyToMono(JSONObject.class)
.flatMap(body -> {
if (MediaType.APPLICATION_JSON.isCompatibleWith(mediaType)) {
//这边可以改变request body的值
System.out.println(body);
body.put("name" ,"重新赋值了");
return Mono.just(body);
}
return Mono.empty();
});
bodyInserter = BodyInserters.fromPublisher(modifiedBodyJson, JSONObject.class);
}
//form表单请求
if (MediaType.APPLICATION_FORM_URLENCODED.isCompatibleWith(mediaType)) {
// read & modify body
modifiedBodyString = serverRequest.bodyToMono(String.class)
.flatMap(body -> {
if (MediaType.APPLICATION_FORM_URLENCODED.isCompatibleWith(mediaType)) {
// origin body map
Map<String, Object> bodyMap = decodeBody(body);
// TODO decrypt & auth
// new body map
Map<String, Object> newBodyMap = new HashMap<>();
newBodyMap.put("name","重新设置呀");
return Mono.just(encodeBody(newBodyMap));
}
return Mono.empty();
});
bodyInserter = BodyInserters.fromPublisher(modifiedBodyString, String.class);
}
HttpHeaders headers = new HttpHeaders();
headers.putAll(exchange.getRequest().getHeaders());
// the new content type will be computed by bodyInserter
// and then set in the request decorator
headers.remove(HttpHeaders.CONTENT_LENGTH);
CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange, headers);
return bodyInserter.insert(outputMessage, new BodyInserterContext())
.then(Mono.defer(() -> {
ServerHttpRequestDecorator decorator = new ServerHttpRequestDecorator(
exchange.getRequest()) {
@Override
public HttpHeaders getHeaders() {
long contentLength = headers.getContentLength();
HttpHeaders httpHeaders = new HttpHeaders();
httpHeaders.putAll(super.getHeaders());
if (contentLength > 0) {
httpHeaders.setContentLength(contentLength);
} else {
httpHeaders.set(HttpHeaders.TRANSFER_ENCODING, "chunked");
}
return httpHeaders;
}
@Override
public Flux<DataBuffer> getBody() {
return outputMessage.getBody();
}
};
return chain.filter(exchange.mutate().request(decorator).build());
}));
}
@Override
public int getOrder() {
return 0;
}
private Map<String, Object> decodeBody(String body) {
return Arrays.stream(body.split("&"))
.map(s -> s.split("="))
.collect(Collectors.toMap(arr -> arr[0], arr -> arr[1]));
}
private String encodeBody(Map<String, Object> map) {
return map.entrySet().stream().map(e -> e.getKey() + "=" + e.getValue()).collect(Collectors.joining("&"));
}
}上述例子中实现了form表单和json请求参数的解析
配置代码：https://github.com/ciweigg2/spring-cloud-examples/tree/spring-cloud-nacos/spring-cloud-clientA
使用postman测试即可 太简单了不做解释了
2个测试接口：
请求参数：
{
"name":"123",
"id":"1"
}对了要先把路有规则配置好 gateway项目中设置
bootstrap.yml
spring:
cloud:
gateway:
routes:
- id: retry_test
uri: lb://eureka-client-a
predicates:
- Path=/hello/**demo：https://github.com/ciweigg2/spring-cloud-examples/tree/spring-cloud-nacos/spring-cloud-gateway
