spring cloud gateway跨域问题

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1、在和axios联调鉴权的时候发现，在增加自定义header的时候会出现跨域问题

image.png

2、因为是跨域请求，前端会首先发送一个options的嗅探请求，一次真正的请求
所以会出现两个403

3、网关之前设置的是全局filter

package net.youqu.micro.service.filter;

import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
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.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

/**
 * description: 跨域访问
 *
 * @author wangpeng
 * @date 2018/09/25
 */
@Component
public class CrossOriginFilter implements GlobalFilter, Ordered {
    private static final String ALL = "*";
    private static final String MAX_AGE = "18000L";


    @Override
    public Mono<Void> filter(ServerWebExchange serverWebExchange, GatewayFilterChain gatewayFilterChain) {
        ServerHttpRequest request = serverWebExchange.getRequest();
//        if (!CorsUtils.isCorsRequest(request)) {
//            return gatewayFilterChain.filter(serverWebExchange);
//        }
        ServerHttpResponse response = serverWebExchange.getResponse();
        HttpHeaders headers = response.getHeaders();
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN, "*");
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_METHODS, "POST, GET, PUT, OPTIONS, DELETE, PATCH");
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_CREDENTIALS, "true");
        headers.add(HttpHeaders.ACCESS_CONTROL_ALLOW_HEADERS, "*");
        headers.add(HttpHeaders.ACCESS_CONTROL_EXPOSE_HEADERS, ALL);
        headers.add(HttpHeaders.ACCESS_CONTROL_MAX_AGE, MAX_AGE);
        if (request.getMethod() == HttpMethod.OPTIONS) {
            response.setStatusCode(HttpStatus.OK);
            return Mono.empty();
        }
        return gatewayFilterChain.filter(serverWebExchange);
    }

    @Override
    public int getOrder() {
        return -300;
    }
}

然而并没有什么卵用，这个是百度出来的配置，看起来没问题，但在前端请求的时候根本就没有进入到这里，就直接拒绝了。
之后又想了下是否是容器层给拒绝了，由于gateway确实用的人比较少，百度了半天都是互相抄的文章，半天有用的没有，只能采用老的办法了，去github上gateway的项目里问作者了。

image.png

结果发现根源在Webflux上边，由于gateway使用的是webflux，而不是springmvc，需要覆盖掉webflux默认的CORS处理配置，通过注册新的CorsWebFilter Bean来解决跨域问题

package net.youqu.micro.service.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.reactive.CorsWebFilter;
import org.springframework.web.cors.reactive.UrlBasedCorsConfigurationSource;
import org.springframework.web.util.pattern.PathPatternParser;

/**
 * description:
 *
 * @author wangpeng
 * @date 2019/01/02
 */
@Configuration
public class CorsConfig {
    @Bean
    public CorsWebFilter corsFilter() {
        CorsConfiguration config = new CorsConfiguration();
        config.addAllowedMethod("*");
        config.addAllowedOrigin("*");
        config.addAllowedHeader("*");

        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource(new PathPatternParser());
        source.registerCorsConfiguration("/**", config);

        return new CorsWebFilter(source);
    }
}

配置式:

spring:
  cloud:
    gateway:
      discovery:
      # 跨域
      globalcors:
        corsConfigurations:
          '[/**]':
            allowedHeaders: "*"
            allowedOrigins: "*"
            allowedMethods:
            - GET
              POST
              DELETE
              PUT
              OPTION

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