Vue3组合式API实战：构建高效可复用的用户认证模块

引言：为什么选择组合式API

在Vue3中，组合式API(Composition API)彻底改变了我们组织和复用代码的方式。与Options API相比，它提供了更灵活的逻辑组织和更好的类型推断支持。本文将带你通过构建一个完整的用户认证模块，深入理解组合式API的强大之处。

项目初始化与基础配置

首先创建一个新的Vue3项目并安装必要依赖：

npm init vue@latest vue-auth-demo
cd vue-auth-demo
npm install axios vue-router pinia

我们将使用Pinia作为状态管理库，axios处理HTTP请求，vue-router管理路由。

核心：创建useAuth组合式函数

在src/composables目录下创建useAuth.js：

import { ref } from 'vue'
import axios from 'axios'
import { useRouter } from 'vue-router'
import { defineStore } from 'pinia'

export const useAuthStore = defineStore('auth', {
  state: () => ({
    user: null,
    token: localStorage.getItem('token') || null
  }),
  // ...
})

export default function useAuth() {
  const router = useRouter()
  const authStore = useAuthStore()
  const isLoading = ref(false)
  const error = ref(null)

  const login = async (credentials) => {
    try {
      isLoading.value = true
      const response = await axios.post('/api/auth/login', credentials)
      authStore.token = response.data.token
      authStore.user = response.data.user
      localStorage.setItem('token', response.data.token)
      router.push('/dashboard')
    } catch (err) {
      error.value = err.response?.data?.message || '登录失败'
    } finally {
      isLoading.value = false
    }
  }

  const logout = () => {
    authStore.token = null
    authStore.user = null
    localStorage.removeItem('token')
    router.push('/login')
  }

  return {
    login,
    logout,
    isLoading,
    error,
    user: computed(() => authStore.user),
    isAuthenticated: computed(() => !!authStore.token)
  }
}

这个组合式函数封装了所有认证相关的逻辑，包括登录、登出、用户状态管理等。

路由守卫实现

在src/router/index.js中配置路由守卫：

import { createRouter, createWebHistory } from 'vue-router'
import { useAuthStore } from '@/composables/useAuth'

const routes = [
  {
    path: '/dashboard',
    component: () => import('@/views/Dashboard.vue'),
    meta: { requiresAuth: true }
  },
  // 其他路由...
]

const router = createRouter({
  history: createWebHistory(),
  routes
})

router.beforeEach((to) => {
  const authStore = useAuthStore()
  if (to.meta.requiresAuth && !authStore.token) {
    return '/login'
  }
})

export default router

在组件中使用

登录组件示例Login.vue：

<script setup>
import { ref } from 'vue'
import useAuth from '@/composables/useAuth'

const { login, isLoading, error } = useAuth()
const credentials = ref({
  email: '',
  password: ''
})
</script>

<template>
  <form @submit.prevent="login(credentials)">
    <div v-if="error" class="error">{{ error }}</div>
    <input v-model="credentials.email" type="email" placeholder="邮箱">
    <input v-model="credentials.password" type="password" placeholder="密码">
    <button :disabled="isLoading">
      {{ isLoading ? '登录中...' : '登录' }}
    </button>
  </form>
</template>

高级技巧：刷新令牌处理

扩展useAuth函数，添加自动刷新令牌逻辑：

// 在useAuth.js中添加
const refreshToken = async () => {
  try {
    const response = await axios.post('/api/auth/refresh', null, {
      headers: {
        Authorization: `Bearer ${authStore.token}`
      }
    })
    authStore.token = response.data.token
    localStorage.setItem('token', response.data.token)
    return true
  } catch {
    logout()
    return false
  }
}

// 添加axios拦截器
axios.interceptors.response.use(
  response => response,
  async error => {
    const originalRequest = error.config
    if (error.response?.status === 401 && !originalRequest._retry) {
      originalRequest._retry = true
      const refreshed = await refreshToken()
      if (refreshed) {
        originalRequest.headers.Authorization = `Bearer ${authStore.token}`
        return axios(originalRequest)
      }
    }
    return Promise.reject(error)
  }
)