修复shiro重定向引起的Response for preflight is invalid (redirect)的网络报错问题

最近集成shiro到项目中，遇到该一个报复Response for preflight is invalid (redirect)的问题。

1. shiro集成，配置无权限的路径

    @Bean(name = "shiroFilter")
    public ShiroFilterFactoryBean shiroFilterFactoryBean(DefaultWebSecurityManager securityManager) {
        ShiroFilterFactoryBean shiroFilterFactoryBean = new ShiroFilterFactoryBean();
        shiroFilterFactoryBean.setSecurityManager(securityManager);
        shiroFilterFactoryBean.setLoginUrl("/unauth");
        shiroFilterFactoryBean.setUnauthorizedUrl("/forbidden");
        Map<String, String> filterMap = InstanceUtil.newLinkedHashMap();
        for (String filter : filters.split("\\;")) {
            String[] keyValue = filter.split("\\=");
            filterMap.put(keyValue[0], keyValue[1]);
        }
        shiroFilterFactoryBean.setFilterChainDefinitionMap(filterMap);
        return shiroFilterFactoryBean;
    }

将登陆地址的url地址配置为/unauth

1. 将无权限的路径配置成返回json数据

   @RequestMapping(value = "/unauth")
    @ResponseBody
    public Object unauth() {
        return ErrorResponseData.newInstance(HttpCode.UNAUTHORIZED, "未登陆");
    }

1. 但在前端调用时，进行options预检时，报以下错误

Failed to load http://127.0.0.1:9080/getUserInfo: Response for preflight is invalid (redirect)
exception.js:32 Error: Network Error
    at createError (createError.js:16)
    at XMLHttpRequest.handleError (xhr.js:87)

经分析，报错原因是进行预检时，没有带上token，倒置会重定向到unauth路径中，所以进行调用时，会报如下错误。
解决办法是通过过滤器，如果判断请求为OPTIONS预检时，直接返回成功。 示例代码如下：

package com.starmark.core.shiro.advice;


import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.stereotype.Component;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
@ServletComponentScan
@WebFilter(urlPatterns = "/*",filterName = "shiroLoginFilter")
public class ShiroLoginFilter  implements Filter {

    private FilterConfig config = null;
    @Override
    public void init(FilterConfig config) throws ServletException {
        this.config = config;
    }
    @Override
    public void destroy() {
        this.config = null;
    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        // 允许哪些Origin发起跨域请求,nginx下正常
        // response.setHeader( "Access-Control-Allow-Origin", config.getInitParameter( "AccessControlAllowOrigin" ) );
        response.setHeader( "Access-Control-Allow-Origin", "*" );
        // 允许请求的方法
        response.setHeader( "Access-Control-Allow-Methods", "POST,GET,OPTIONS,DELETE,PUT" );
        // 多少秒内，不需要再发送预检验请求，可以缓存该结果
        response.setHeader( "Access-Control-Max-Age", "3600" );
        // 表明它允许跨域请求包含xxx头
        response.setHeader( "Access-Control-Allow-Headers", "x-auth-token,Origin,Access-Token,X-Requested-With,Content-Type, Accept" );
        //是否允许浏览器携带用户身份信息（cookie）
        response.setHeader( "Access-Control-Allow-Credentials", "true" );
        // response.setHeader( "Access-Control-Expose-Headers", "*" );
        if (request.getMethod().equals( "OPTIONS" )) {
            response.setStatus( 200 );
            return;
        }
        filterChain.doFilter( servletRequest, response );
    }


}

加入该过滤器后，解决了。