前言

在管理系统中最让人头疼的就是权限管理了，今天和大家一起讨论下在Vue技术栈中怎么实现简单实用用户的权限控制，权限控制一般分为路由、视图、接口等方面。首先学习一下vuerouter的的基础知识及如何配置路由

路由基础知识

<router-link :to="'home'">Home</router-link>

<router-link :to="{ path: 'home' }">Home</router-link>

<router-link :to="{ name: 'user', params: { userId: 123 }}">User</router-link>
等同于router.push()

当然除了to是必须配置的属性外，router-link还有一系列的属性让开发能够更加灵活的控制路由切换及样式上的优化，router-link会被渲染成<a href="home"></a>当然通过配置也可以修改渲染成其他html元素具体可以参考官方文档

  <keep-alive>
    <router-view></router-view>
  </keep-alive>

<router-view> 组件是一个 functional 组件，渲染路径匹配到的视图组件。<router-view> 渲染的组件还可以内嵌自己的 <router-view>，根据嵌套路径，渲染嵌套组件。

Router 实例方法

router.beforeEach((to, from, next) => {
  /* must call `next` */
})

router.beforeResolve((to, from, next) => {
  /* must call `next` */
})

router.afterEach((to, from) => {})
 
router.push()
router.replace()
router.go()
router.back()
router.forward()
router.addRoutes

VueRouter新版本添加了addRouter的方法，通过此方法可以在登录成功后搭配Vuex的动态生成符合用户权限的路由

路由表配置

import Vue from 'vue'
import Router from 'vue-router'

Vue.use(Router)
import Layout from '../views/layout/Layout'

export const constantRouterMap = [
  { path: '/login', component: () => import('@/views/login/index'), hidden: true },
  { path: '/404', component: () => import('@/views/404'), hidden: true },

  {
    path: '/',
    component: Layout,
    redirect: '/dashboard',
    name: 'Dashboard',
    hidden: true,
    children: [{
      path: 'dashboard',
      component: () => import('@/views/dashboard/index')
    }]
  }
]

export default new Router({
  // mode: 'history', //后端支持可开
  scrollBehavior: () => ({ y: 0 }),
  routes: constantRouterMap
})

export const asyncRouterMap = [
  {
    path: '/example',
    component: Layout,
    redirect: '/example/table',
    name: 'Example',
    meta: { title: '案例', roles: ['admin', 'editor', 'guest'] },
    children: [
      {
        path: 'table',
        name: 'Table',
        component: () => import('@/views/table/index'),
        meta: { title: '表格', roles: ['admin', 'editor'] }
      },
      {
        path: 'tree',
        name: 'Tree',
        component: () => import('@/views/tree/index'),
        meta: { title: '树形菜单', roles: ['admin', 'editor'] }
      }
    ]
  },

  {
    path: '/form',
    component: Layout,
    children: [
      {
        path: 'index',
        name: 'Form',
        component: () => import('@/views/form/index'),
        meta: { title: '表单', roles: ['admin'] }
      }
    ]
  },

  {
    path: '/nested',
    component: Layout,
    redirect: '/nested/menu1',
    name: 'Nested',
    meta: {
      title: '树形菜单',
      roles: ['admin']
    },
    children: [
      {
        path: 'menu1',
        component: () => import('@/views/nested/menu1/index'), // Parent router-view
        name: 'Menu1',
        meta: { title: '菜单1' },
        children: [
          {
            path: 'menu1-1',
            component: () => import('@/views/nested/menu1/menu1-1'),
            name: 'Menu1-1',
            meta: { title: '菜单1-1' }
          },
          {
            path: 'menu1-2',
            component: () => import('@/views/nested/menu1/menu1-2'),
            name: 'Menu1-2',
            meta: { title: '菜单1-2' },
            children: [
              {
                path: 'menu1-2-1',
                component: () => import('@/views/nested/menu1/menu1-2/menu1-2-1'),
                name: 'Menu1-2-1',
                meta: { title: '菜单1-2-1' }
              },
              {
                path: 'menu1-2-2',
                component: () => import('@/views/nested/menu1/menu1-2/menu1-2-2'),
                name: 'Menu1-2-2',
                meta: { title: '菜单1-2-2' }
              }
            ]
          },
          {
            path: 'menu1-3',
            component: () => import('@/views/nested/menu1/menu1-3'),
            name: 'Menu1-3',
            meta: { title: '菜单1-3' }
          }
        ]
      },
      {
        path: 'menu2',
        component: () => import('@/views/nested/menu2/index'),
        meta: { title: '菜单2' }
      }
    ]
  },

  { path: '*', redirect: '/404', hidden: true }
]

路由表动态生成

借助router.beforEach钩子函数、我们可以在每次跳转路由的时候实现用户的登录信息的获取、访问权限、和登录是否失效、是否是白名单等功能具体代码如下

import router from './router'
import store from './store'
import { Message } from 'element-ui'
import { getToken } from '@/utils/auth' // 验权

const whiteList = ['/login'] // 不重定向白名单
router.beforeEach((to, from, next) => {
  if (getToken()) {
    if (to.path === '/login') {
      next({ path: '/' })
    } else {
      if (store.getters.roles.length === 0) {
        store.dispatch('GetInfo').then(res => { // 拉取用户信息
          const roles = res.data.roles
          store.dispatch('GenerateRoutes', { roles }).then(() => { // 根据roles权限生成可访问的路由表
            router.addRoutes(store.getters.addRouters) // 动态添加可访问路由表
            next({ ...to, replace: true }) // hack方法 确保addRoutes已完成 ,set the replace: true so the navigation will not leave a history record
          })
        }).catch((err) => {
          store.dispatch('FedLogOut').then(() => {
            Message.error(err || 'Verification failed, please login again')
            next({ path: '/' })
          })
        })
      } else {
        next()
      }
    }
  } else {
    if (whiteList.indexOf(to.path) !== -1) {
      next()
    } else {
      next(`/login?redirect=${to.path}`) // 否则全部重定向到登录页
    }
  }
})

router.afterEach(() => {
})

import { asyncRouterMap, constantRouterMap } from '@/router'

/**
 * 通过meta.role判断是否与当前用户权限匹配
 * @param roles
 * @param route
 */
function hasPermission(roles, route) {
  if (route.meta && route.meta.roles) {
    return roles.some(role => route.meta.roles.includes(role))
  } else {
    return true
  }
}

/**
 * 递归过滤异步路由表，返回符合用户角色权限的路由表
 * @param routes asyncRouterMap
 * @param roles
 */
function filterAsyncRouter(routes, roles) {
  const res = []

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

  return res
}

const permission = {
  state: {
    routers: constantRouterMap,
    addRouters: []
  },
  mutations: {
    SET_ROUTERS: (state, routers) => {
      state.addRouters = routers
      state.routers = constantRouterMap.concat(routers)
    }
  },
  actions: {
    GenerateRoutes({ commit }, data) {
      return new Promise(resolve => {
        const { roles } = data
        let accessedRouters
        if (roles.includes('admin')) {
          accessedRouters = asyncRouterMap
        } else {
          accessedRouters = filterAsyncRouter(asyncRouterMap, roles)
        }
        commit('SET_ROUTERS', accessedRouters)
        resolve()
      })
    }
  }
}

export default permission

总结

今天主要是从角色方面来控制用户的权限， 基本可以满足大部分人的需求，当然不是万能的，如果某些项目要求权限的控制更加颗粒化，单凭角色是不可取的，可以实现只不过需要增加很多的角色和频繁的修改路由表的配置，大家业余时间可以自己去研究发现更好的办法。