spring cloud gateway

spring cloud gateway - 日志

实现日志

前提：spring cloud gateway是基于webflux的项目，所以不能像使用spring mvc一样直接获取request body。

参考博客：

SpringCloud Gateway获取post请求体(request body)
获取SpringCloud gateway 响应的response的值，可以查看、修改

下面会讲述两种获取request body的方式（对应不同的版本）

第一种：重新构造再转发

如果我们在spring cloud gateway 封装之前读取了一次request body，比如打印request body日志，在下游获取数据的时候会出现错误：[spring cloud] [error] java.lang.IllegalStateException: Only one connection receive subscriber allowed. 因为request body只能读取一次，它是属于消费类型的。

实现思路为：

首先读取原请求的数据，然后构造一个新的请求，将原请求的数据封装到新的请求中，然后再转发出去。

这种方法在spring-boot-starter-parent 2.0.6.RELEASE + Spring Cloud Finchley.SR2 body 中生效

但是在spring-boot-starter-parent 2.1.0.RELEASE + Spring Cloud Greenwich.M3 body 中不生效，总是为空

重写的拦截方法filter

@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {Route gatewayUrl = exchange.getRequiredAttribute(ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR);URI uri = gatewayUrl.getUri();ServerHttpRequest request = (ServerHttpRequest)exchange.getRequest();String URIPath = request.getURI().toString();String path = request.getPath().value();String method = request.getMethodValue();String instance = uri.getAuthority();HttpHeaders header = request.getHeaders();//缓存读取的request body信息AtomicReference<String> bodyRef = new AtomicReference<>();Flux<DataBuffer> fluxBody = exchange.getRequest().getBody();fluxBody.subscribe(buffer -> {CharBuffer charBuffer = StandardCharsets.UTF_8.decode(buffer.asByteBuffer());DataBufferUtils.release(buffer);bodyRef.set(charBuffer.toString());});String bodyStr = bodyRef.get();//获取request bodylog.info("请求体参数：{}",bodyStr);       //封装新的requestDataBuffer bodyDataBuffer = stringBuffer(bodyStr);Flux<DataBuffer> bodyFlux = Flux.just(bodyDataBuffer);request = new ServerHttpRequestDecorator(request){@Overridepublic Flux<DataBuffer> getBody() {return bodyFlux;}}; return chain.filter(exchange.mutate().request(request).build());
}

缓存body的方法

protected 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;
}

第二种：获取缓存里面的body

这种方式就是解决在spring-boot-starter-parent 2.1.0.RELEASE + Spring Cloud Greenwich.M3 body 中不生效，总是为空的问题

实现思路：

在filter中通过cachedRequestBodyObject缓存字段获取request body信息，这种解决，一不会带来重复读取问题，二不会带来requestbody取不全问题。三在低版本的Spring Cloud Finchley.SR2也可以运行。

路由配置：

在配置中添加Predicate方法readBody（Object.class,requestBody -> true）

@Bean
public RouteLocator routeLocatorPermission(RouteLocatorBuilder builder) {return builder.routes().route(PERMISSION_ROUTE_ID,r -> r.path(PERMISSION_ROUTE_PATH).and().readBody(Object.class,requestBody -> true).filters(f -> f.stripPrefix(3).hystrix(config -> config.setName("hystrixName").setFallbackUri("forward:/fallback")).requestRateLimiter(config -> config.setKeyResolver(ipKeyResolver).setRateLimiter(myRedisRateLimiter)).filter(oauthFilter)).uri("lb://BOSS-BES-PERMISSION")).build();
}

配置日志拦截

可以通过Object requestBody = exchange.getAttribute("cachedRequestBodyObject")直接获取body

@Component
public class GatewayRequestLogFilter implements GlobalFilter, Ordered {private static Logger logger = LoggerFactory.getLogger(GatewayRequestLogFilter.class);@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {ServerHttpRequest request = exchange.getRequest();logger.info("path: " + request.getPath());logger.info("address: " + request.getRemoteAddress());logger.info("method: " + request.getMethodValue());logger.info("URI: " + request.getURI());logger.info("Headers: " + request.getHeaders());Object requestBody = exchange.getAttribute("cachedRequestBodyObject");logger.info("body: "+ requestBody);return chain.filter(exchange);}@Overridepublic int getOrder() {return Ordered.HIGHEST_PRECEDENCE;}
}

注意事项：

如果是get请求，get请求使用readBody会报错

如果是post请求，Content-Type是application/x-www-form-urlencoded，readbody为 String.class

如果是post请求，Content-Type是application/json,readbody为 Object.class

最后附上响应拦截记录日志代码：

@Component
public class GatewayResponseLogFilter implements GlobalFilter, Ordered {private static Logger logger = LoggerFactory.getLogger(GatewayResponseLogFilter.class);@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {ServerHttpResponse originalResponse = exchange.getResponse();DataBufferFactory bufferFactory = originalResponse.bufferFactory();ServerHttpResponseDecorator decoratedResponse = new ServerHttpResponseDecorator(originalResponse) {@Override@SuppressWarnings("unchecked")public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {if (body instanceof Flux) {Flux<? extends DataBuffer> fluxBody = (Flux<? extends DataBuffer>) body;return super.writeWith(fluxBody.map(dataBuffer -> {byte[] content = new byte[dataBuffer.readableByteCount()];dataBuffer.read(content);DataBufferUtils.release(dataBuffer);String result = new String(content, Charset.forName("UTF-8"));logger.info("response body: " + result);byte[] uppedContent = new String(content, Charset.forName("UTF-8")).getBytes();return bufferFactory.wrap(uppedContent);}));}return super.writeWith(body);}};return chain.filter(exchange.mutate().response(decoratedResponse).build());}@Overridepublic int getOrder() {return -2;}
}