一、补坑总结提前说明
我的项目有一个前台MVC项目门户站点(用户登录信息存储在cookie)，和后台vue项目（用户登录信息存储在localstorage）站点，2个站点分属不同的端口，那就是跨域了。之前我已经实现过了某个站点登录后，可以直接进入对方站点实现自动登录，也就是单点登录的效果，现在我要实现单点退出登录的效果，其实按理说原理跟登录是差不多的。参考之前写的单点登录跳转文章外部链接跳转到vue项目传递参数实现单点登录_吹牛不交税的博客-CSDN博客

但是我碰到了巨坑，折腾了我一天，大致总结如下：
http://localhost:9990//loginout?from=portal  昨天一直用的这个链接去跳转后台退出登录，但是到了后台之后，有个
const router = createRouter({
  history: myhistory, //createWebHistory(process.env.BASE_URL),
  routes
})
这里总是会人为的给链接路由换成/home。    然后我早上上厕所的时候想了一下之前登录成功跳转的链接，他是带了参了#/home/ 和参数过去，登录跳转可以，那我就把登录跳转的#/home/  放到前面，后面再加loginout和参数，变成下面这样，
http://localhost:9990/#/home/loginout?dXNlck5hbWU9dW5kZWZpbmVkJnVzZXJfSWQ9dW5kZWZpbmVkJmltZz11bmRlZmluZWQmdG9rZW49dW5kZWZpbmVk&from=portal
 他就不会直接把路由替换成 /home了，原因是啥我也不知道  ，createRouter 是vue内部函数，我昨天调试了很久都没调试出所以然。 
这策略就是变成了，我打不过他我就顺从他。

二、vue项目退出登录后跳转门户mvc项目的退出登录地址。

我的vue项目，原始退出登录的代码他就是一个函数调用store.commit('clearUserInfo', ''); 清除用户信息在前端的缓存，然后通过跳转跟路径"/"让系统自动判断重新跳转到登录路由就完事了。
那我现在想要在执行完跳转的时候还要跳转到别的站点链接，我就得单独做一个loginout的路由页面。

1、 loginout.vue路由文件代码，我开始尝试了想动态生成iframe，通过iframe的src属性执行外部链接，但是失败了，但是里面关于生成iframe的代码我没有删除，关于跳转最重要的几句就是下面的这几行。myhostname变量是站点根域名或者IP，http.portalUrl是端口（配置的门户站点端口），from=houtai用来告诉门户，是从后台跳转过去的请求，而且这里也有判断是否从门户跳转过来的链接（from=portal），如果是门户跳转过来的链接，就不能再跳转回去了，那就成了多次循环跳转了。

 let myhostname = location.hostname;
    let portal_loginout = "http://" + myhostname + ":" + http.portalUrl + "index/loginout?from=houtai";    
    if (location.href.indexOf("from=portal") < 0) {    
      location.href = portal_loginout;
    }

<template>
  <div id="divdom" ref="divdom">
    <!-- <iframe id="myframe"></iframe> -->
  </div>
</template>

<script>
import loading from "@/components/basic/RouterLoading";
import VolMenu from "@/components/basic/VolElementMenu.vue";
import Message from "./index/Message.vue";
import MessageConfig from "./index/MessageConfig.js";

import {
  defineComponent,
  reactive,
  ref,
  watch,
  onMounted,
  getCurrentInstance,
} from "vue";
import { useRouter, useRoute } from "vue-router";
import store from "../store/index";
import http from "@/../src/api/http.js";
import { HttpResponse } from "@microsoft/signalr";
import base64 from 'js-base64';
const jsBase64 = require('js-base64').Base64; //js-base64 加密

export default defineComponent({
  components: {

  },

  data() {
    return {

      //  contextMenuVisible: false, // 右键关闭显/隐
    };
  },
  setup(props, context) {
    store.commit('clearUserInfo', '');
    const loading = ref(false);
    const codeImgSrc = ref('');
    const userInfo = reactive({
      userName: '',
      password: '',
      verificationCode: '',
      UUID: undefined
    });
    let appContext = getCurrentInstance().appContext;
    let $message = appContext.config.globalProperties.$message;
    let router = useRouter();
    $message.success('退出成功,正在跳转!');

    return {
      loading,
      codeImgSrc,
      userInfo,
    };
  },
  /**
   * 挂载钩子函数
   */
  mounted() {
    // alert("111");
    // debugger;
    let myhostname = location.hostname;
    let portal_loginout = "http://" + myhostname + ":" + http.portalUrl + "index/loginout?from=houtai";
    // alert(portal_loginout);
    let mydom = this.$refs.divdom;       
    if (location.href.indexOf("from=portal") < 0) {
      // this.createIframe(mydom, portal_loginout, null);
      location.href = portal_loginout;
    }
  },

  methods: {

    /**
    * 动态创建iframe
    * @param dom 创建iframe的容器，即在dom中创建iframe。dom能够是div、span或者其它标签。
    * @param src iframe中打开的网页路径
    * @param onload iframe载入完后触发该事件。能够为空
    * @return 返回创建的iframe对象
    * */
    createIframe(dom, src, onload) {
      //在document中创建iframe
      var iframe = document.createElement("iframe");
      //设置iframe的样式
      iframe.style.width = "100%";
      iframe.style.height = "100%";
      iframe.style.margin = "0";
      iframe.style.padding = "0";
      iframe.style.overflow = "hidden";
      iframe.style.border = "none";
      //绑定iframe的onload事件,处理事件的兼容问题
      if (onload && Object.prototype.toString.call(onload) === "[object Function]") {
        if (iframe.attachEvent) {
          iframe.attachEvent("onload", onload);
        }
        else if (iframe.addEventListener) {
          iframe.addEventListener("load", onload);
        }
        else {
          iframe.onload = onload;
        }
      }
      iframe.src = src;
      //把iframe载入到dom以下
      dom.appendChild(iframe);
      return iframe;
    },


  },
  created() {

  },
  /**
   * 销毁钩子函数
   */
  destroyed() {
    $this = null;
    clearInterval($interval);
  },
});
</script>

2、 router/index.js 路由配置文件中，增加一个路由

{

    path: '/loginout',

    name: 'loginout',

    component: () => import('@/views/Loginout.vue'),

    redirect: '/loginout',

    meta: {

      anonymous: true

    }

  },

 这个文件下面还有一个位置router.beforeEach 的时候要增加以下判断  

if(to.fullPath.indexOf("loginout")>0)

  {  

    return next();   

  }

3、在退出登录按钮执行的代码位置，加一行代码跳转到loginout路由

 三、门户MVC项目退出登录，然后跳转到后台vue项目的路由

1、退出登录按钮位置的代码

2、loginout路由的后端代码没有写什么东西，就将config配置的后端跳转路由啥的读取存到ViewBag。

ViewBag.adminUrl = _adminUrl;
            ViewBag.portapiurl = _portapiurl;
            return View();

3、loginout.cshtml 文件代码   

重点代码段：

 var cookietokenvalue = $.cookie('portalusertoken');
        var cookieusername = $.cookie('portalusername');
        var portaluserid = $.cookie('portaluserid');
        var portalimg = $.cookie('portalimg'); 
        var portapiurl = $.cookie('_portapiurl');

        var adminUrl = getCookie('_adminUrl');
        adminUrl = $("#hid_adminurl").val() ;

        var myurlhouzhui = "/loginout?" + Base64.encode("userName=" + encodeURI(cookieusername) + "&user_Id=" + portaluserid + "&img=" + portalimg + "&token=" + cookietokenvalue)+"&from=portal";
        if (adminUrl != undefined && adminUrl != null && adminUrl != "null" && adminUrl != "" && location.href.indexOf("&from=houtai") < 0) {
            var myhostname = location.hostname;
            var myadmin_arr = adminUrl.split("%2F");
            var portal_loginout = "http://" + myhostname + ":" + adminUrl + myurlhouzhui;   //"/loginout?from=portal"
            //alert(portal_loginout);
            //var mydom = $("#divdom");
            //var mydom = document.querySelector("divdom");
            //this.createIframe(mydom, portal_loginout, null);
            debugger;
            window.location.href = portal_loginout;
            //window.open(portal_loginout);
        }

@*
    For more information on enabling MVC for empty projects, visit https://go.microsoft.com/fwlink/?LinkID=397860
*@
@{
    Layout = "_Layout.cshtml";
}

<html lang="zh-CN">

<head>

    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta property="og:title" content="Digital Marketplace Template" />
    <meta property="og:type" content="website" />
    <meta property="og:url" content="" />
    <meta property="og:image" content="" />

    <link rel="stylesheet" href="~/portal/assets/css/preloader.css" />
    <script src="~/portal/assets/js/preloader.js"></script>


    <link rel="stylesheet" href="~/portal/assets/css/vendor/bootstrap.min.css" />
    <link rel="stylesheet" href="~/portal/assets/css/vendor/nice-select.css" />
    <link rel="stylesheet" href="~/portal/assets/css/vendor/magnific-popup.css" />
    <link rel="stylesheet" href="~/portal/assets/css/vendor/slick.css" />
    <link rel="stylesheet" href="~/portal/assets/css/vendor/aos.css" />
    <link rel="stylesheet" href="~/portal/assets/css/style.css" />
    <title>造价师服务平台</title>

    <script src="~/portal/assets/js/vendor/jquery.min.js"></script>
    <script src="~/portal/assets/js/vendor/jquery.nice-select.min.js"></script>
    <script src="~/portal/assets/js/jquery.cookie.min.js"></script>

    <script src="~/Scripts/My97DatePicker/WdatePicker.js"></script>
    <script src="~/js/js-base64-3.7.5/package/base64.js"></script>

</head>
<body> 
    <div id="divdom" ref="divdom">
        <!-- <iframe id="myframe"></iframe> -->
    </div>

    <input type="hidden" id="hid_adminurl" value="@ViewBag.adminUrl" />
    <input type="hidden" id="hid_portapiurl" value="@ViewBag.portapiurl" />

    <script>
        /**
        * 动态创建iframe
        * param dom 创建iframe的容器，即在dom中创建iframe。dom能够是div、span或者其它标签。
        * param src iframe中打开的网页路径
        * param onload iframe载入完后触发该事件。能够为空
        * return 返回创建的iframe对象
        * */
        function createIframe(dom, src, onload) {
            //在document中创建iframe
            var iframe = document.createElement("iframe");
            //设置iframe的样式
            iframe.style.width = "100%";
            iframe.style.height = "100%";
            iframe.style.margin = "0";
            iframe.style.padding = "0";
            iframe.style.overflow = "hidden";
            iframe.style.border = "none";
            //绑定iframe的onload事件,处理事件的兼容问题
            if (onload && Object.prototype.toString.call(onload) === "[object Function]") {
                if (iframe.attachEvent) {
                    iframe.attachEvent("onload", onload);
                }
                else if (iframe.addEventListener) {
                    iframe.addEventListener("load", onload);
                }
                else {
                    iframe.onload = onload;
                }
            }
            iframe.src = src;
            //把iframe载入到dom以下
            dom.appendChild(iframe);
            return iframe;
        }
         
        /**
        *设置 cookie 值的函数,创建一个函数用于存储访问者的名字
        *cname:名称，必须字母
        *cvalue：值
        *exdays：过期时间（天）
        * */
        var setCookie = function (cname, cvalue, exdays) {
            var d = new Date();
            d.setTime(d.getTime() + (exdays * 24 * 60 * 60 * 1000));
            var expires = "expires=" + d.toGMTString();
            document.cookie = cname + "=" + cvalue + "; " + expires + ";path=/";
        };
         

        //获取 cookie 值的函数,创建一个函数用户返回指定 cookie 的值
        //cname:名称，你之前设置的名称
        var getCookie = function (cname) {
            var name = cname + "=";
            var ca = document.cookie.split(';');
            for (var i = 0; i < ca.length; i++) {
                var c = ca[i].trim();
                if (c.indexOf(name) == 0) return c.substring(name.length, c.length);
            }
            return null;
        };

       

        
        $.ajax({
            type: "get",
            url: "/index/tologinout",
            async: false,
            success: function (res) {
                debugger;
                $.cookie("portalusertoken", null, { path: '/', expires: -1 }); //删除hello
                $.cookie("portalusername", null, { path: '/', expires: -1 }); //删除hello
                $.cookie("portaluserid", null, { path: '/', expires: 10 }); //删除hello
                $.cookie("portalimg", null, { path: '/', expires: 10 }); //删除hello
                //重新指向首页
                var myhostname = location.hostname;
                var port = window.location.port;
                var myindexurl = "http://" + myhostname + ":" + port + "/index/index";
                location.href = myindexurl;
            }
        });
        $.cookie("portalusertoken", null, { path: '/', expires: -1 }); //删除hello
        $.cookie("portalusername", null, { path: '/', expires: -1 }); //删除hello
        $.cookie("portaluserid", null, { path: '/', expires: -1 }); //删除hello
        $.cookie("portalimg", null, { path: '/', expires: -1 }); //删除hello
        //重新指向首页
        //var myhostname = location.hostname;
        //var port = window.location.port;
        //var myindexurl = "http://" + myhostname + ":" + port + "/index/index";
        //location.href = myindexurl;

        var cookietokenvalue = $.cookie('portalusertoken');
        var cookieusername = $.cookie('portalusername');
        var portaluserid = $.cookie('portaluserid');
        var portalimg = $.cookie('portalimg'); 
        var portapiurl = $.cookie('_portapiurl');

        var adminUrl = getCookie('_adminUrl');
        adminUrl = $("#hid_adminurl").val() ;

        var myurlhouzhui = "/loginout?" + Base64.encode("userName=" + encodeURI(cookieusername) + "&user_Id=" + portaluserid + "&img=" + portalimg + "&token=" + cookietokenvalue)+"&from=portal";
        if (adminUrl != undefined && adminUrl != null && adminUrl != "null" && adminUrl != "" && location.href.indexOf("&from=houtai") < 0) {
            var myhostname = location.hostname;
            var myadmin_arr = adminUrl.split("%2F");
            var portal_loginout = "http://" + myhostname + ":" + adminUrl + myurlhouzhui;   //"/loginout?from=portal"
            //alert(portal_loginout);
            //var mydom = $("#divdom");
            //var mydom = document.querySelector("divdom");
            //this.createIframe(mydom, portal_loginout, null);
            debugger;
            window.location.href = portal_loginout;
            //window.open(portal_loginout);
        }

    </script>
</body>


</html>