![](http://img.szonline.cn/2022/1118/20221118104248143.jpg)
有時(shí)候,我們需要對(duì)所有微服務(wù)跨域請(qǐng)求進(jìn)行處理.
(資料圖)
跨域的說明:
哪些場(chǎng)景是跨域:不同的系統(tǒng)進(jìn)行AJAX的請(qǐng)求的時(shí)候?qū)儆诳缬虻摹?跨域的請(qǐng)求一般是不被允許的。
1.www.jd.com---->www.taobao.com 跨域
2.localhost:8001 —>localhost:8002 跨域
3.www.jd.com:80—>www.jd.com:81 跨域
4.https —>http 跨域。
域名相同,端口相同,協(xié)議相同 就不是跨域。
解決跨域的問題的解決方案:CORS的協(xié)議 (高版本的瀏覽器至少 IE10 google)在服務(wù)端進(jìn)行注解配置(相當(dāng)配置了CORS的配置項(xiàng))springmvc的注解 @CrossOrigin通過在網(wǎng)關(guān)(spring cloud gateway)進(jìn)行統(tǒng)一的配置通過在網(wǎng)關(guān)(nginx里面進(jìn)行配置CORS)JSONP的方式(了解) 利用JS的漏洞的實(shí)現(xiàn)跨域,而且只支持GET請(qǐng)求 不支持其他的請(qǐng)求。解決方式涉及到圖如下:
通過@CrossOrigin()注解實(shí)現(xiàn)
如果都需要跨域處理,該方式需要在每一個(gè)Controller類上配置。
另外我們一般在SpringCloudGateway網(wǎng)關(guān)配置
spring: cloud: gateway: globalcors: corsConfigurations: "[/**]": allowedOriginPatterns: "*" allowed-methods: "*" allowed-headers: "*" allow-credentials: true exposedHeaders: "Content-Disposition,Content-Type,Cache-Control"
如果不想配置到y(tǒng)ml也可以代碼寫在網(wǎng)關(guān)模塊中
import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.http.HttpHeaders;import org.springframework.http.HttpMethod;import org.springframework.http.HttpStatus;import org.springframework.http.server.reactive.ServerHttpRequest;import org.springframework.http.server.reactive.ServerHttpResponse;import org.springframework.web.cors.reactive.CorsUtils;import org.springframework.web.server.ServerWebExchange;import org.springframework.web.server.WebFilter;import org.springframework.web.server.WebFilterChain;import reactor.core.publisher.Mono;/** * 跨域配置 */@Configurationpublic class CorsConfig{ /** * 這里為支持的請(qǐng)求頭,如果有自定義的header字段請(qǐng)自己添加 */ private static final String ALLOWED_HEADERS = "X-Requested-With, Content-Type, Authorization, credential, X-XSRF-TOKEN, token, Admin-Token, App-Token"; private static final String ALLOWED_METHODS = "GET,POST,PUT,DELETE,OPTIONS,HEAD"; private static final String ALLOWED_ORIGIN = "*"; private static final String ALLOWED_EXPOSE = "*"; private static final String MAX_AGE = "18000L"; @Bean public WebFilter corsFilter() { return (ServerWebExchange ctx, WebFilterChain chain) -> { ServerHttpRequest request = ctx.getRequest(); if (CorsUtils.isCorsRequest(request)) { ServerHttpResponse response = ctx.getResponse(); HttpHeaders headers = response.getHeaders(); headers.add("Access-Control-Allow-Headers", ALLOWED_HEADERS); headers.add("Access-Control-Allow-Methods", ALLOWED_METHODS); headers.add("Access-Control-Allow-Origin", ALLOWED_ORIGIN); headers.add("Access-Control-Expose-Headers", ALLOWED_EXPOSE); headers.add("Access-Control-Max-Age", MAX_AGE); headers.add("Access-Control-Allow-Credentials", "true"); if (request.getMethod() == HttpMethod.OPTIONS) { response.setStatusCode(HttpStatus.OK); return Mono.empty(); } } return chain.filter(ctx); }; }}
前端頁(yè)面通過不同域名或IP訪問SpringCloud Gateway,那么,此時(shí)直連微服務(wù)和網(wǎng)關(guān)的跨域問題都解決了,是不是很完美?
No~ 問題來了,前端仍然會(huì)報(bào)錯(cuò):“不允許有多個(gè)’Access-Control-Allow-Origin’ CORS頭”。
問題:Vary 和 Access-Control-Allow-Origin 兩個(gè)頭重復(fù)了兩次,其中瀏覽器對(duì)后者有唯一性限制!
解決方式之一:手動(dòng)寫一個(gè) CorsResponseHeaderFilter 的 GlobalFilter 去修改Response中的頭。
import org.springframework.cloud.gateway.filter.GatewayFilterChain;import org.springframework.cloud.gateway.filter.GlobalFilter;import org.springframework.cloud.gateway.filter.NettyWriteResponseFilter;import org.springframework.core.Ordered;import org.springframework.http.HttpHeaders;import org.springframework.stereotype.Component;import org.springframework.web.server.ServerWebExchange;import reactor.core.publisher.Mono;import java.util.ArrayList;import java.util.List;import java.util.stream.Collectors;@Componentpublic class CorsResponseHeaderFilter implements GlobalFilter, Ordered { private static final String ANY = "*"; @Override public int getOrder() { // 指定此過濾器位于NettyWriteResponseFilter之后 // 即待處理完響應(yīng)體后接著處理響應(yīng)頭 return NettyWriteResponseFilter.WRITE_RESPONSE_FILTER_ORDER + 1; } @Override @SuppressWarnings("serial") public Monofilter(ServerWebExchange exchange, GatewayFilterChain chain) { return chain.filter(exchange).then(Mono.fromRunnable(() -> { exchange.getResponse().getHeaders().entrySet().stream() .filter(kv -> (kv.getValue() != null && kv.getValue().size() > 1)) .filter(kv -> (kv.getKey().equals(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN) || kv.getKey().equals(HttpHeaders.ACCESS_CONTROL_ALLOW_CREDENTIALS) || kv.getKey().equals(HttpHeaders.VARY))) .forEach(kv -> { // Vary只需要去重即可 if(kv.getKey().equals(HttpHeaders.VARY)) kv.setValue(kv.getValue().stream().distinct().collect(Collectors.toList())); else{ List value = new ArrayList<>(); if(kv.getValue().contains(ANY)){ //如果包含*,則取* value.add(ANY); kv.setValue(value); }else{ value.add(kv.getValue().get(0)); // 否則默認(rèn)取第一個(gè) kv.setValue(value); } } }); })); }}
基于SpringCloudGateway網(wǎng)關(guān)配置完成。