一、前序工作

因为我是用template来开发的；所以简单了做了几个页面测试
在开始之前简单说一下vue-element-admin 的路由
它的路由有两种： 一种是通用页面路由constantRoutes；还有一种是动态路由 asyncRoutes
通用路由是可以直接挂载在页面的；不需要权限判断；我们要解决的是动态路由挂载

注意文件夹位置：src/router/index.js
添加asyncRoutes

export const asyncRoutes = [
  {
    path: '/permission',
    component: Layout,
    redirect: '/permission/test1',
    alwaysShow: true, // will always show the root menu
    name: 'Permission',
    meta: {
      title: 'Permission',
      icon: 'lock',
      roles: ['admin', 'editor'] // you can set roles in root nav
    },
    children: [
      {
        path: 'test1',
        component: () => import('@/views/permission/test1'),
        name: 'Test1',
        meta: {
          title: 'Permission test1',
          roles: ['admin'] // or you can only set roles in sub nav
        }
      },
      {
        path: 'test2',
        component: () => import('@/views/permission/test2'),
        name: 'Test2',
        meta: {
          title: 'Permission test2',
          roles: ['admin'] // or you can only set roles in sub nav
        }
      },
      {
        path: 'test3',
        component: () => import('@/views/permission/test3'),
        name: 'Test3',
        meta: {
          title: 'Permission test3'
          // if do not set roles, means: this page does not require permission
        }
      }
    ]

  },
  // 404 page must be placed at the end !!!
  { path: '*', redirect: '/404', hidden: true }
]

二、根据权限动态加载路由

1.挂载前的验证

注意路径：src/permission.js

router.beforeEach(async(to, from, next) => {
  // start progress bar
  NProgress.start()

  // set page title
  document.title = getPageTitle(to.meta.title)

  // determine whether the user has logged in
  const hasToken = getToken()

  // 判断是否存在token,没有就重新登陆
  if (hasToken) {
    if (to.path === '/login') {
      // if is logged in, redirect to the home page
      next({ path: '/' })
      NProgress.done()
    } else {
      // determine whether the user has obtained his permission roles through getInfo
      const hasRoles = store.getters.roles && store.getters.roles.length > 0//这里指的是src/store/getters.js的roles
      console.log(hasRoles)
      //判断是否已经有roles了
      if (hasRoles) {
        next()
      } else {
        try {
          // get user info
          // note: roles must be a object array! such as: ['admin'] or ,['developer','editor']
          //获取roles
          const { roles } = await store.dispatch('user/getInfo')//第一步

          // generate accessible routes map based on roles
          //获取通过权限验证的路由
          const accessRoutes = await store.dispatch('permission/generateRoutes', roles)//第二步
          //更新加载路由
          router.options.routes = store.getters.permission_routes//第三步
          // dynamically add accessible routes
          router.addRoutes(accessRoutes)
          console.log(store)
          // hack method to ensure that addRoutes is complete
          // set the replace: true, so the navigation will not leave a history record
          next({ ...to, replace: true })
        } catch (error) {
          // remove token and go to login page to re-login
          await store.dispatch('user/resetToken')
          Message.error(error || 'Has Error')
          next(`/login?redirect=${to.path}`)
          NProgress.done()
        }
      }
    }
     } else {
    /* has no token*/

    if (whiteList.indexOf(to.path) !== -1) {
      // in the free login whitelist, go directly
      next()
    } else {
      // other pages that do not have permission to access are redirected to the login page.
      next(`/login?redirect=${to.path}`)
      NProgress.done()
    }
  }
})

这里分了核心三步，第一步获取用户个人信息（角色）；第二部筛选用户可以看见的路由；第三步更新加载路由

2.保存一些相关信息

注意路径：src/store/modules/user.js
注意roles和SET_ROLES是必须的

const getDefaultState = () => {
  return {
    token: getToken(),
    name: '',
    avatar: '',
    introduction: '',
    roles: []
  }
}

const state = getDefaultState()

const mutations = {
  RESET_STATE: (state) => {
    Object.assign(state, getDefaultState())
  },
  SET_TOKEN: (state, token) => {
    state.token = token
  },
  SET_INTRODUCTION: (state, introduction) => {
    state.introduction = introduction
  },
  SET_NAME: (state, name) => {
    state.name = name
  },
  SET_AVATAR: (state, avatar) => {
    state.avatar = avatar
  },
  SET_ROLES: (state, roles) => {
    state.roles = roles
  }
}

3.获取用户角色

注意路径：src/store/modules/user.js

  // get user info
  getInfo({ commit, state }) {
    return new Promise((resolve, reject) => {
      //我这里用的是post请求获取个人信息
      getInfo({ token: state.token }).then(response => {
        //注意这个data,有一些初学者或者粗心的人会被这里卡一下这里涉及到es6的解构函数；
        const { data } = response
		
        if (!data) {
          reject('Verification failed, please Login again.')
        }
		//返回的info最少需要包含以下内容（角色，名称，头像，简介）个人需求
		//大家可以只返回roles就行了
        const { roles, name, avatar, introduction } = data
        
        if (!roles || roles.length <= 0) {
          reject('getInfo: roles must be a non-null array!')
        }
        console.log(roles)
		//存起来
        commit('SET_ROLES', roles)
        commit('SET_NAME', name)
        commit('SET_AVATAR', avatar)
        commit('SET_INTRODUCTION', introduction)
        resolve(data)
      }).catch(error => {
        reject(error)
      })
    })
  },

注意路径：src/store/getters.js

4.筛选路由

注意路径：src/store/modules/permission.js
直接把vue-element-admin的这个页面复制下来就好了

import { asyncRoutes, constantRoutes } from '@/router'

/**
 * Use meta.role to determine if the current user has permission
 * @param roles
 * @param route
 */
//匹配权限
function hasPermission(roles, route) {
  if (route.meta && route.meta.roles) {
    return roles.some(role => route.meta.roles.includes(role))
  } else {
    return true
  }
}

/**
 * Filter asynchronous routing tables by recursion
 * @param routes asyncRoutes
 * @param roles
 */
export function filterAsyncRoutes(routes, roles) {
  const res = []

  routes.forEach(route => {
    const tmp = { ...route }
    if (hasPermission(roles, tmp)) {
      if (tmp.children) {
        tmp.children = filterAsyncRoutes(tmp.children, roles)
      }
      res.push(tmp)
    }
  })

  return res
}

const state = {
  routes: [],
  addRoutes: []
}

const mutations = {
  SET_ROUTES: (state, routes) => {
    state.addRoutes = routes
    state.routes = constantRoutes.concat(routes) // 将过滤后的路由和constantRoutes存起来
  }
}

//筛选
const actions = {
  generateRoutes({ commit }, roles) {
    return new Promise(resolve => {
      let accessedRoutes
      //路由是否有admin,有直接全部显示
      if (roles.includes('admin')) {
        accessedRoutes = asyncRoutes || []
      } else {
        //过滤路由
        accessedRoutes = filterAsyncRoutes(asyncRoutes, roles)
        //accessedRoutes这个就是当前角色可见的动态路由
      }
      commit('SET_ROUTES', accessedRoutes)
      resolve(accessedRoutes)
    })
  }
}

export default {
  namespaced: true,
  state,
  mutations,
  actions
}

5最后的加载

这就是之前的第三步

 router.options.routes = store.getters.permission_routes

很多人直接用router.addRoutes(accessRoutes)发现无法更新路由，但是路由是被定义了的；后面看文档，是因为Router的路由并不是响应式的，所以只能读取到初始路由。然后要在router.addRoutes(accessRoutes),加上那句话就可以了
或者参考一下大佬的加载方法
手摸手，带你用vue撸后台 系列二(登录权限篇)

6效果截图

三、遇到的bug

1.data functions should return an object:

这个问题是返回的内容格式不对；报错的地方是 src/permission.js

2.动态路由显示不成功的原因

1.有可能是没有更新出来；就如同我的2.5小结，Router的路由并不是响应式的，所以只能读取到初始路由；所以显示不出来
2. 这个路由必须放在最后{ path: '*', redirect: '/404', hidden: true }，因为path:’*’ 代表所有路由；如果放在前面会卡住后面的路由，导致显示失败

四、结尾

因为是本人的实践所得；如果有什么错误或者不足指出之处请指出，我会立马改正
参考了大佬的文章
手摸手，带你用vue撸后台 系列二(登录权限篇)