spring cloud gateway如何獲取請求的真實地址

更新時間：2023年05月06日 09:06:28 作者：一只豬啊啊

這篇文章主要介紹了spring cloud gateway如何獲取請求的真實地址問題，具有很好的參考價值，希望對大家有所幫助。如有錯誤或未考慮完全的地方，望不吝賜教

spring cloud gateway獲取請求的真實地址

在使用spring cloud gateway的時候，路由一般配置為服務(wù)名

例如 lb://BASE-API-WEB/xxx/bbb 路徑，我們無從知道，他真正路由到什么地方去了。

經(jīng)過查看源碼我發(fā)現(xiàn)了，

org.springframework.cloud.gateway.filter.LoadBalancerClientFilter

這個filter中對lb請求進行了處理，轉(zhuǎn)換成真正的url地址。

核心方法如下

 public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
       //lb下的url
 URI url = (URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
        String schemePrefix = (String)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR);
        if (url == null || !"lb".equals(url.getScheme()) && !"lb".equals(schemePrefix)) {
            return chain.filter(exchange);
        } else {
            ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url);
            log.trace("LoadBalancerClientFilter url before: " + url);
            ServiceInstance instance = this.loadBalancer.choose(url.getHost());
            if (instance == null) {
                throw new NotFoundException("Unable to find instance for " + url.getHost());
            } else {
                URI uri = exchange.getRequest().getURI();
                String overrideScheme = null;
                if (schemePrefix != null) {
                    overrideScheme = url.getScheme();
                }
                //真實的url
                URI requestUrl = this.loadBalancer.reconstructURI(new LoadBalancerClientFilter.DelegatingServiceInstance(instance, overrideScheme), uri);
                log.trace("LoadBalancerClientFilter url chosen: " + requestUrl);
                exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl);
                return chain.filter(exchange);
            }
        }
    }

其實，spring cloud gateway 已經(jīng)打印了日志，但是默認(rèn)的他是trace級別的，我們常用的日志級別是info級別，所有他不會打印，這就導(dǎo)致了我們在日志中看不到真實的url地址

以下是解決辦法

1.在配置文件中設(shè)置org.springframework.cloud.gateway.filter.LoadBalancerClientFilter的日志級別

logging.level.org.springframework.cloud.gateway.filter.LoadBalancerClientFilter=TRACE

注意這里的配置一定要在

logging.level.org.springframework之后配置 不然會覆蓋

2.重寫LoadBalancerClientFilter 建立org.springframework.cloud.gateway.filter包將類重寫 spingboot默認(rèn)會從本項目中加載類，原先的類就被棄用了。

3.繼承LoadBalancerClientFilter 重寫filter方法，將日志級別改為info即可

  @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        URI url = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
        String schemePrefix = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR);
        if (url == null || !"lb".equals(url.getScheme()) && !"lb".equals(schemePrefix)) {
            return chain.filter(exchange);
        } else {
            ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url);
            ServiceInstance instance = this.loadBalancer.choose(url.getHost());
            if (instance == null) {
                throw new NotFoundException("Unable to find instance for " + url.getHost());
            } else {
                URI uri = exchange.getRequest().getURI();
                String overrideScheme = null;
                if (schemePrefix != null) {
                    overrideScheme = url.getScheme();
                }
                URI requestUrl = this.loadBalancer.reconstructURI(new LoadBalancerClientFilterBean.DelegatingServiceInstance(instance, overrideScheme), uri);
                logger.info("before url = {} , url chosen = {} " ,url, requestUrl);
                exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl);
                return chain.filter(exchange);
            }
        }
    }

最終效果如下：