SpringCloud gateway request的body验证或修改

心已赠人 2022-02-27 20:08 316阅读 0赞

2019.11.05更新：

后续版本新增了以下过滤器

org.springframework.cloud.gateway.filter.headers.RemoveHopByHopHeadersFilter

默认会把以下头部移除（暂不了解这做法的目的）

- connection
    - keep-alive
    - te
    - transfer-encoding
    - trailer
    - proxy-authorization
    - proxy-authenticate
    - x-application-context
    - upgrade

从而导致下面我们重写getHeaders方法时添加的transfer-encoding头部移除，导致无法解析body。

解决办法：

在yml文件中配置自定义的头部移除列表

spring:
      cloud:
          filter:
            remove-hop-by-hop:
              headers:
                - connection
                - keep-alive
                - te
                - trailer
                - proxy-authorization
                - proxy-authenticate
                - x-application-context
                - upgrade

**源码可见链接，且可实现动态路由配置：**[https://github.com/SingleTigger/SpringCloudGateway-Nacos-Demo][https_github.com_SingleTigger_SpringCloudGateway-Nacos-Demo]

\--------------------------------------------原文----------------------------------------------------

往往业务中我们需要在网关对请求参数作修改操作（注意以下只针对带有body的请求），springcloud gateway中有提供一个

ModifyRequestBodyGatewayFilterFactory

的filter，看了一下它的实现，需要指定输入类型和输出类型，比较局限。

我就参考它自己实现了一个拦截器

注意：上传文件也带有请求body，需特殊处理。

以下是主要代码

import org.springframework.cloud.gateway.filter.GatewayFilter;
    import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
    import org.springframework.cloud.gateway.support.BodyInserterContext;
    import org.springframework.core.io.buffer.DataBuffer;
    import org.springframework.http.HttpHeaders;
    import org.springframework.http.codec.HttpMessageReader;
    import org.springframework.http.server.reactive.ServerHttpRequest;
    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.HandlerStrategies;
    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.List;
    import java.util.concurrent.atomic.AtomicReference;
    import java.util.function.BiFunction;
    
    /**
     * @author chenws
     * @date 2019/12/12 09:33:53
     */
    @Component
    public class CModifyRequestBodyGatewayFilterFactory extends AbstractGatewayFilterFactory {
    
        private final List<HttpMessageReader<?>> messageReaders;
    
        public CModifyRequestBodyGatewayFilterFactory() {
            this.messageReaders = HandlerStrategies.withDefaults().messageReaders();
        }
    
        @Override
        @SuppressWarnings("unchecked")
        public GatewayFilter apply(Object config) {
            return (exchange, chain) -> {
                ServerRequest serverRequest = ServerRequest.create(exchange,
                        this.messageReaders);
    
                Mono<String> modifiedBody = serverRequest.bodyToMono(String.class)
                        .flatMap(originalBody -> modifyBody()
                                .apply(exchange,Mono.just(originalBody)));
    
                BodyInserter bodyInserter = BodyInserters.fromPublisher(modifiedBody,
                        String.class);
                HttpHeaders headers = new HttpHeaders();
                headers.putAll(exchange.getRequest().getHeaders());
                headers.remove(HttpHeaders.CONTENT_LENGTH);
    
                CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange,
                        headers);
                return bodyInserter.insert(outputMessage, new BodyInserterContext())
                        .then(Mono.defer(() -> {
                            ServerHttpRequest decorator = decorate(exchange, headers,
                                    outputMessage);
                            return chain.filter(exchange.mutate().request(decorator).build());
                        }));
    
            };
        }
    
        /**
         * 修改body
         * @return apply 返回Mono<String>，数据是修改后的body
         */
        private BiFunction<ServerWebExchange,Mono<String>,Mono<String>> modifyBody(){
            return (exchange,json)-> {
                AtomicReference<String> result = new AtomicReference<>();
                json.subscribe(
                        value -> {
                            //value 即为请求body，在此处修改
                            result.set(value);
                            System.out.println(result.get());
                        },
                        Throwable::printStackTrace
                );
                return Mono.just(result.get());
            };
        }
    
        private ServerHttpRequestDecorator decorate(ServerWebExchange exchange, HttpHeaders headers,
                                            CachedBodyOutputMessage outputMessage) {
            return 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();
                }
            };
        }
    }

如需转载请标明出处：[https://blog.csdn.net/shuoshuo132][https_blog.csdn.net_shuoshuo132]

[https_github.com_SingleTigger_SpringCloudGateway-Nacos-Demo]: https://github.com/SingleTigger/SpringCloudGateway-Nacos-Demo
[https_blog.csdn.net_shuoshuo132]: https://blog.csdn.net/shuoshuo132