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來(lái)源：juejin.cn/post/7004756545741258765
前言
本文記錄一下我是如何使用Gateway搭建網(wǎng)關(guān)服務(wù)及實(shí)現(xiàn)動(dòng)態(tài)路由的，幫助大家學(xué)習(xí)如何快速搭建一個(gè)網(wǎng)關(guān)服務(wù)，了解路由相關(guān)配置，鑒權(quán)的流程及業(yè)務(wù)處理，有興趣的一定看到最后，非常適合沒(méi)接觸過(guò)網(wǎng)關(guān)服務(wù)的同學(xué)當(dāng)作入門教程。
搭建服務(wù)
框架
SpringBoot 2.1
<parent>
???<groupId>org.springframework.bootgroupId>
???<artifactId>spring-boot-starter-parentartifactId>
???<version>2.1.0.RELEASEversion>
parent>
Spring-cloud-gateway-core
<dependency>
???<groupId>org.springframework.cloudgroupId>
???<artifactId>spring-cloud-gateway-coreartifactId>
dependency>
common-lang3
<dependency>
???<groupId>org.apache.commonsgroupId>
???<artifactId>commons-lang3artifactId>
dependency>
路由配置
網(wǎng)關(guān)作為請(qǐng)求統(tǒng)一入口，路由就相當(dāng)于是每個(gè)業(yè)務(wù)系統(tǒng)的入口，通過(guò)路由規(guī)則則可以匹配到對(duì)應(yīng)微服務(wù)的入口，將請(qǐng)求命中到對(duì)應(yīng)的業(yè)務(wù)系統(tǒng)中。
server:
??port:?8080

spring:
??cloud:
????gateway:
??????enabled:?true
??????routes:
??????-?id:?demo-server
????????uri:?http://localhost:8081
????????predicates:
????????-?Path=/demo-server/**
????????filters:
??????????-?StripPrefix=?1
routes
解讀配置
現(xiàn)在有一個(gè)服務(wù)demo-server部署在本機(jī)，地址和端口為127.0.0.1:8081，所以路由配置uri為http://localhost:8081
使用網(wǎng)關(guān)服務(wù)路由到此服務(wù)，predicates -Path=/demo-server/**,網(wǎng)關(guān)服務(wù)的端口為8080，啟動(dòng)網(wǎng)關(guān)服務(wù)，訪問(wèn)localhost:8080/demo-server,路由斷言就會(huì)將請(qǐng)求路由到demo-server
直接訪問(wèn)demo-server的接口localhost:8081/api/test,通過(guò)網(wǎng)關(guān)的訪問(wèn)地址則為localhost:8080/demo-server/api/test,predicates配置將請(qǐng)求斷言到此路由，filters-StripPrefix=1代表將地址中/后的第一個(gè)截取，所以demo-server就截取掉了
使用gateway通過(guò)配置文件即可完成路由的配置，非常方便，我們只要充分的了解配置項(xiàng)的含義及規(guī)則就可以了;但是這些配置如果要修改則需要重啟服務(wù)，重啟網(wǎng)關(guān)服務(wù)會(huì)導(dǎo)致整個(gè)系統(tǒng)不可用，這一點(diǎn)是無(wú)法接受的，下面介紹如何通過(guò)Nacos實(shí)現(xiàn)動(dòng)態(tài)路由
動(dòng)態(tài)路由
使用nacos結(jié)合gateway-server實(shí)現(xiàn)動(dòng)態(tài)路由，我們需要先部署一個(gè)nacos服務(wù)，可以使用docker部署或下載源碼在本地啟動(dòng),具體操作可以參考官方文檔即可。另外搜索公眾號(hào)互聯(lián)網(wǎng)架構(gòu)師后臺(tái)回復(fù)“2T”，獲取一份驚喜禮包。
Nacos配置
groupId: 使用網(wǎng)關(guān)服務(wù)名稱即可
dataId: routes
配置格式：json
[{
??????"id":?"xxx-server",
??????"order":?1,?#優(yōu)先級(jí)
??????"predicates":?[{?#路由斷言
??????????"args":?{
??????????????"pattern":?"/xxx-server/**"
??????????},
??????????"name":?"Path"
??????}],
??????"filters":[{?#過(guò)濾規(guī)則
??????????"args":?{
??????????????"parts":?0?#k8s服務(wù)內(nèi)部訪問(wèn)容器為http://xxx-server/xxx-server的話,配置0即可
??????????},
??????????"name":?"StripPrefix"?#截取的開(kāi)始索引
??????}],
??????"uri":?"http://localhost:8080/xxx-server"?#目標(biāo)地址
??}]
json格式配置項(xiàng)與yaml中對(duì)應(yīng)，需要了解配置在json中的寫法
比對(duì)一下json配置與yaml配置
{
????"id":"demo-server",
????"predicates":[
????????{
????????????"args":{
????????????????"pattern":"/demo-server/**"
????????????},
????????????"name":"Path"
????????}
????],
????"filters":[
????????{
????????????"args":{
????????????????"parts":1
????????????},
????????????"name":"StripPrefix"
????????}
????],
????"uri":"http://localhost:8081"
}
spring:
??cloud:
????gateway:
??????enabled:?true
??????routes:
??????-?id:?demo-server
????????uri:?http://localhost:8081
????????predicates:
????????-?Path=/demo-server/**
????????filters:
??????????-?StripPrefix=?1
代碼實(shí)現(xiàn)
Nacos實(shí)現(xiàn)動(dòng)態(tài)路由的方式核心就是通過(guò)Nacos配置監(jiān)聽(tīng)，配置發(fā)生改變后執(zhí)行網(wǎng)關(guān)相關(guān)api創(chuàng)建路由
@Component
public?class?NacosDynamicRouteService?implements?ApplicationEventPublisherAware?{

????private?static?final?Logger?LOGGER?=?LoggerFactory.getLogger(NacosDynamicRouteService.class);

????@Autowired
????private?RouteDefinitionWriter?routeDefinitionWriter;

????private?ApplicationEventPublisher?applicationEventPublisher;

????/**?路由id?*/
????private?static?List?routeIds?=?Lists.newArrayList();

????/**
?????*?監(jiān)聽(tīng)nacos路由配置，動(dòng)態(tài)改變路由
?????*?@param?configInfo
?????*/
????@NacosConfigListener(dataId?=?"routes",?groupId?=?"gateway-server")
????public?void?routeConfigListener(String?configInfo)?{
????????clearRoute();
????????try?{
????????????List?gatewayRouteDefinitions?=?JSON.parseArray(configInfo,?RouteDefinition.class);
????????????for?(RouteDefinition?routeDefinition?:?gatewayRouteDefinitions)?{
????????????????addRoute(routeDefinition);
????????????}
????????????publish();
????????????LOGGER.info("Dynamic?Routing?Publish?Success");
????????}?catch?(Exception?e)?{
????????????LOGGER.error(e.getMessage(),?e);
????????}
????????
????}


????/**
?????*?清空路由
?????*/
????private?void?clearRoute()?{
????????for?(String?id?:?routeIds)?{
????????????routeDefinitionWriter.delete(Mono.just(id)).subscribe();
????????}
????????routeIds.clear();
????}

????@Override
????public?void?setApplicationEventPublisher(ApplicationEventPublisher?applicationEventPublisher)?{
????????this.applicationEventPublisher?=?applicationEventPublisher;
????}

????/**
?????*?添加路由
?????*?
?????*?@param?definition
?????*/
????private?void?addRoute(RouteDefinition?definition)?{
????????try?{
????????????routeDefinitionWriter.save(Mono.just(definition)).subscribe();
????????????routeIds.add(definition.getId());
????????}?catch?(Exception?e)?{
????????????LOGGER.error(e.getMessage(),?e);
????????}
????}

????/**
?????*?發(fā)布路由、使路由生效
?????*/
????private?void?publish()?{
????????this.applicationEventPublisher.publishEvent(new?RefreshRoutesEvent(this.routeDefinitionWriter));
????}
}
過(guò)濾器
gateway提供GlobalFilter及Ordered兩個(gè)接口用來(lái)定義過(guò)濾器，我們自定義過(guò)濾器只需要實(shí)現(xiàn)這個(gè)兩個(gè)接口即可
GlobalFilter filter()?實(shí)現(xiàn)過(guò)濾器業(yè)務(wù)
Ordered getOrder()?定義過(guò)濾器執(zhí)行順序
通常一個(gè)網(wǎng)關(guān)服務(wù)的過(guò)濾主要包含 鑒權(quán)（是否登錄、是否黑名單、是否免登錄接口...） 限流（ip限流等等）功能，我們今天簡(jiǎn)單介紹鑒權(quán)過(guò)濾器的流程實(shí)現(xiàn)
鑒權(quán)過(guò)濾器
需要實(shí)現(xiàn)鑒權(quán)過(guò)濾器，我們先得了解登錄及鑒權(quán)流程，如下圖所示
由圖可知，我們鑒權(quán)過(guò)濾核心就是驗(yàn)證token是否有效，所以我們網(wǎng)關(guān)服務(wù)需要與業(yè)務(wù)系統(tǒng)在同一個(gè)redis庫(kù)，先給網(wǎng)關(guān)添加redis依賴及配置
<dependency>
????<groupId>org.springframework.bootgroupId>
????<artifactId>spring-boot-starter-data-redis-reactiveartifactId>
dependency>
spring:
??redis:
????host:?redis-server
????port:?6379
????password:
????database:?0
代碼實(shí)現(xiàn)
定義過(guò)濾器AuthFilter
獲取請(qǐng)求對(duì)象 從請(qǐng)求頭或參數(shù)或cookie中獲取token(支持多種方式傳token對(duì)于客戶端更加友好，比如部分web下載請(qǐng)求會(huì)新建一個(gè)頁(yè)面，在請(qǐng)求頭中傳token處理起來(lái)比較麻煩)。另外搜索公眾號(hào)互聯(lián)網(wǎng)架構(gòu)師后臺(tái)回復(fù)“Spring”，獲取一份驚喜禮包。
沒(méi)有token,返回401
有token，查詢r(jià)edis是否有效
無(wú)效則返回401，有效則完成驗(yàn)證放行
重置token過(guò)期時(shí)間、添加內(nèi)部請(qǐng)求頭信息方便業(yè)務(wù)系統(tǒng)權(quán)限處理
@Component
public?class?AuthFilter?implements?GlobalFilter,?Ordered?{

????@Autowired
????private?RedisTemplate?redisTemplate;

????private?static?final?String?TOKEN_HEADER_KEY?=?"auth_token";

????@Override
????public?Mono?filter(ServerWebExchange?exchange,?GatewayFilterChain?chain)?{
????????//?1.獲取請(qǐng)求對(duì)象
????????ServerHttpRequest?request?=?exchange.getRequest();
????????//?2.獲取token
????????String?token?=?getToken(request);
????????ServerHttpResponse?response?=?exchange.getResponse();
????????if?(StringUtils.isBlank(token))?{
????????????//?3.token為空?返回401
????????????response.setStatusCode(HttpStatus.UNAUTHORIZED);
????????????return?response.setComplete();
????????}
????????//?4.驗(yàn)證token是否有效
????????String?userId?=?getUserIdByToken(token);
????????if?(StringUtils.isBlank(userId))?{
????????????//?5.token無(wú)效?返回401
????????????response.setStatusCode(HttpStatus.UNAUTHORIZED);
????????????return?response.setComplete();
????????}
????????//?token有效，后續(xù)業(yè)務(wù)處理
????????//?從寫請(qǐng)求頭，方便業(yè)務(wù)系統(tǒng)從請(qǐng)求頭獲取用戶id進(jìn)行權(quán)限相關(guān)處理
????????ServerHttpRequest.Builder?builder?=?exchange.getRequest().mutate();
????????request?=?builder.header("user_id",?userId).build();
????????//?延長(zhǎng)緩存過(guò)期時(shí)間-token緩存用戶如果一直在操作就會(huì)一直重置過(guò)期
????????//?這樣避免用戶操作過(guò)程中突然過(guò)期影響業(yè)務(wù)操作及體驗(yàn)，只有用戶操作間隔時(shí)間大于緩存過(guò)期時(shí)間才會(huì)過(guò)期
????????resetTokenExpirationTime(token,?userId);
????????//?完成驗(yàn)證
????????return?chain.filter(exchange);
????}


????@Override
????public?int?getOrder()?{
????????//?優(yōu)先級(jí)?越小越優(yōu)先
????????return?0;
????}

????/**
?????*?從redis中獲取用戶id
?????*?在登錄操作時(shí)候?登陸成功會(huì)生成一個(gè)token,?redis得key為auth_token:token?值為用戶id
?????*
?????*?@param?token
?????*?@return
?????*/
????private?String?getUserIdByToken(String?token)?{
????????String?redisKey?=?String.join(":",?"auth_token",?token);
????????return?redisTemplate.opsForValue().get(redisKey);
????}

????/**
?????*?重置token過(guò)期時(shí)間
?????*
?????*?@param?token
?????*?@param?userId
?????*/
????private?void?resetTokenExpirationTime(String?token,?String?userId)?{
????????String?redisKey?=?String.join(":",?"auth_token",?token);
????????redisTemplate.opsForValue().set(redisKey,?userId,?2,?TimeUnit.HOURS);
????}


????/**
?????*?獲取token
?????*
?????*?@param?request
?????*?@return
?????*/
????private?static?String?getToken(ServerHttpRequest?request)?{
????????HttpHeaders?headers?=?request.getHeaders();
????????//?從請(qǐng)求頭獲取token
????????String?token?=?headers.getFirst(TOKEN_HEADER_KEY);
????????if?(StringUtils.isBlank(token))?{
????????????//?請(qǐng)求頭無(wú)token則從url獲取token
????????????token?=?request.getQueryParams().getFirst(TOKEN_HEADER_KEY);
????????}
????????if?(StringUtils.isBlank(token))?{
????????????//?請(qǐng)求頭和url都沒(méi)有token則從cookies獲取
????????????HttpCookie?cookie?=?request.getCookies().getFirst(TOKEN_HEADER_KEY);
????????????if?(cookie?!=?null)?{
????????????????token?=?cookie.getValue();
????????????}
????????}
????????return?token;
????}
}
總結(jié)
Gateway通過(guò)配置項(xiàng)可以實(shí)現(xiàn)路由功能，整合Nacos及配置監(jiān)聽(tīng)可以實(shí)現(xiàn)動(dòng)態(tài)路由，實(shí)現(xiàn)GlobalFilter, Ordered兩個(gè)接口可以快速實(shí)現(xiàn)一個(gè)過(guò)濾器，文中也詳細(xì)的介紹了登錄后的請(qǐng)求鑒權(quán)流程，如果有不清楚地方可以評(píng)論區(qū)見(jiàn)咯。


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