SpringCloud gateway request的body验证或修改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
————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 */@Componentpublic 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(); } }; }}
SpringCloud Gateway获取post请求体(request body)不完整解决方案
Spring Cloud Gateway做为网关服务，通过gateway进行请求转发，在请求到达后端服务前我们可以通过filter进行一些预处理如：请求的合法性，商户验证等。
如我们在请求体中添加商户ID（merId）和商户KEY（merkey），通过此来验证请求的合法性。但是如果我们请求内容太长如转为base64的文件存储请求。此时我们在filter获取body内容就会被截取(太长的 Body 会被截断)。目前网上也没有好的解决方式。
springboot及Cloud版本如下；
这里提供一种解决方式，相关代码如下：
1.Requestfilter
我们采用Gateway网关的Gobalfilter，建立我们的第一个过滤器过滤所有请求。
1).通过Spring 5 的 WebFlux我们使用bodyToMono方法把响应内容转换成类 String的对象，最终得到的结果是 Mono对象
2).bodyToMono方法我们可以拿到完整的body内容，并返回String。
3).我们生成唯一的token（通过UUID），并将token放入请求的header中。
4).将获取到的完整body内容，存放到redis中。
@Componentpublic class RequestFilter implements GlobalFilter, Ordered {@Autowiredprivate RedisClientTemplate redisClientTemplate;@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {DefaultServerRequest req = new DefaultServerRequest( exchange );String token = UUID.randomUUID().toString();//向headers中放入token信息ServerHttpRequest serverHttpRequest =exchange.getRequest().mutate().header("token", token).build();//将现在的request变成change对象ServerWebExchange build = exchange.mutate().request( serverHttpRequest ).build();return req.bodyToMono( String.class ).map( str -> {redisClientTemplate.setObjex( "microservice:gateway:".concat( token ), 180, str );MySlf4j.textInfo( "请求参数:{0}", str );return str;} ).then( chain.filter( build ) );}@Overridepublic int getOrder() {return 0;}}
2.MerchantAuthFilter
建立商户认证过滤器，相关代码如下：
1).获取存储在headers中的token。
2).通过token获取我们存储在redis中的body内容(WebFlux 中不能使用阻塞的操作，目前想到的是通过这种方式实现)。
3).获取到完整的body内容后我们就可以进行相应的商户认证操作。
4).认证通过，将信息重新写入，不通过则返回异常信息。
@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {/** 验证商户是否有权限访问 */ServerHttpRequest serverHttpRequest = exchange.getRequest();String token = serverHttpRequest.getHeaders().get( "token" ).get( 0 ); String bodyStr = (String) redisClientTemplate.getObj("microservice:gateway:".concat(token));BaseReqVo baseReqVo = JsonUtil.fromJson( bodyStr, BaseReqVo.class );try {// 商户认证BaseRespVo<?> baseRespVo = merchantAuthService.checkMerchantAuth( baseReqVo );if (MicroserviceConstantParamUtils.RESULT_CODE_SUCC.equals( baseRespVo.getCode() )) { // 若验证成功，将信息重新写入避免request信息消费后后续无法从request获取信息的问题 URI uri = serverHttpRequest.getURI(); ServerHttpRequest request = serverHttpRequest.mutate().uri(uri).build(); DataBuffer bodyDataBuffer = stringBuffer(bodyStr); Flux<DataBuffer> bodyFlux = Flux.just(bodyDataBuffer); request = new ServerHttpRequestDecorator(request) { @Override public Flux<DataBuffer> getBody() { return bodyFlux; } };// 封装request，传给下一级 return chain.filter(exchange.mutate().request(request).build());} else {// 若验证不成功，返回提示信息return gatewayResponse( baseRespVo.getCode(), baseRespVo.getMessage(), exchange );}} catch (MicroserviceServiceException ex) {// 若验证不成功，返回提示信息MySlf4j.textError( "商户访问权限验证异常，异常代码:{0},异常信息:{1}, 异常{2}", ex.getCode(), ex.getMessage(), ex );return gatewayResponse( ex.getCode(), ex.getMessage(), exchange );} catch (Exception ex) {MySlf4j.textError( "商户访问权限验证服务异常:{0}", LogUtil.ExceptionToString( ex ) );return gatewayResponse( MicroserviceException.ERR_100000, "系统异常", exchange );} finally {redisClientTemplate.del( "microservice:gateway:".concat( token ) );}}/**数据流处理方法*/private DataBuffer stringBuffer(String value) {byte[] bytes = value.getBytes( StandardCharsets.UTF_8 );NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory( ByteBufAllocator.DEFAULT );DataBuffer buffer = nettyDataBufferFactory.allocateBuffer( bytes.length );buffer.write( bytes );return buffer;}/**网关请求响应*/private Mono<Void> gatewayResponse(String code, String message, ServerWebExchange exchange) {// 若验证不成功，返回提示信息ServerHttpResponse response = exchange.getResponse();BaseRespVo<T> baseRespVo = ResponseUtils.responseMsg( code, message, null );byte[] bits = JsonUtil.toJson( baseRespVo ).getBytes( StandardCharsets.UTF_8 );DataBuffer buffer = response.bufferFactory().wrap( bits );response.setStatusCode( HttpStatus.UNAUTHORIZED );// 指定编码，否则在浏览器中会中文乱码response.getHeaders().add( "Content-Type", "text/plain;charset=UTF-8" );return response.writeWith( Mono.just( buffer ) );}@Overridepublic int getOrder() {return 1;}
另外我们还可以通过GlobalFilter实现请求过滤，OAUTH授权，相关代码如下：
请求方式验证过滤器（RequestAuthFilter）：
@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) { ServerHttpRequest serverHttpRequest = exchange.getRequest(); String method = serverHttpRequest.getMethodValue(); if (!"POST".equals(method)) { ServerHttpResponse response = exchange.getResponse(); BaseRespVo<T> baseRespVo = ResponseUtils.responseMsg(MicroserviceException.ERR_100008, "非法请求", null); byte[] bits = JsonUtil.toJson(baseRespVo).getBytes(StandardCharsets.UTF_8); DataBuffer buffer = response.bufferFactory().wrap(bits); response.setStatusCode(HttpStatus.UNAUTHORIZED); //指定编码，否则在浏览器中会中文乱码 response.getHeaders().add("Content-Type", "text/plain;charset=UTF-8"); return response.writeWith(Mono.just(buffer)); } return chain.filter(exchange); }
OAUTH授权过滤器（OAuthSignatureFilter）：
/**授权访问用户名*/@Value("${spring.security.user.name}")private String securityUserName;/**授权访问密码*/@Value("${spring.security.user.password}")private String securityUserPassword;@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) { /**oauth授权*/ String auth = securityUserName.concat(":").concat(securityUserPassword); String encodedAuth = new sun.misc.BASE64Encoder().encode(auth.getBytes(Charset.forName("US-ASCII"))); String authHeader = "Basic " + encodedAuth; //向headers中放授权信息 ServerHttpRequest serverHttpRequest = exchange.getRequest().mutate().header("Authorization", authHeader) .build(); //将现在的request变成change对象 ServerWebExchange build = exchange.mutate().request(serverHttpRequest).build(); return chain.filter(build);}
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。
理想的路总是为有信心的人预备着
