什么是跨域
        简单来说就是违背了浏览器的同源策略，指协议，域名，端口都要相同，其中有一个不同都会产生跨域。

RoYi-Cloud如何解决跨域
配置方式：
                通过在gateway的nacos中的gateway.yml添加以下配置

spring:
  cloud:
    gateway:
      globalcors:
        corsConfigurations:
          '[/**]':
            allowedOriginPatterns: "*"
            allowed-methods: "*"
            allowed-headers: "*"
            allow-credentials: true
            exposedHeaders: "Content-Disposition,Content-Type,Cache-Control"
代码方式：                
                在gateway项目中新增CorsConfig.java

package com.ruoyi.gateway.config;
 
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
 * 
 * @author ruoyi
 */
@Configuration
public class CorsConfig
{
    /**
     * 这里为支持的请求头，如果有自定义的header字段请自己添加
     */
    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);
        };
    }
}
Nginx反向代理方式：
location /api {
    add_header Access-Control-Allow-Origin http://localhost:3000 always;
    add_header Access-Control-Allow-Headers "Accept,Accept-Encoding,Accept-Language,Connection,Content-Length,Content-Type,Host,Origin,Referer,User-Agent";
    add_header Access-Control-Allow-Methods "GET, POST, PUT, OPTIONS";
    add_header Access-Control-Allow-Credentials true;
    if ($request_method = 'OPTIONS') {
        return 200;
    }
    proxy_cookie_domain ~\.?duck.com $host;
    proxy_pass https://duck.com;
}
参数解析
allowedOriginPatterns: 放行域名，可以多个，用","分割

allowed-methods: 放行请求方式，可以多个，例如

"GET", "HEAD", "POST", "PUT", "DELETE", "OPTIONS", "PATCH"
allowed-headers: 放行头部信息

allow-credentials: 是否发送Cookie信息

exposedHeaders: 暴露哪些头部信息（因为跨域访问默认不能获取全部头部信息）
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版权声明：本文为CSDN博主「小黄鸭技术」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/weixin_40579395/article/details/128017427