在之前任务用户登录成功后，完成手动文件上传过程（可以借助UI框架），文件上传过程需进行token验证，验证token有效才能完成文件上传，实现前后端代码，并提交核心代码代码块

前端代码：

<template>
  <div>
    <input type="file" @change="handleFileUpload">
  </div>
</template>

<script>
import axios from 'axios'

export default {
  methods: {
    async handleFileUpload(event) {
      const file = event.target.files[0]
      const token = localStorage.getItem('token')
      const formData = new FormData()
      formData.append('file', file)
      try {
        const response = await axios.post('http://example.com/upload', formData, {
          headers: {
            Authorization: `Bearer ${token}`
          }
        })
        console.log(response.data)
      } catch (error) {
        console.error(error)
      }
    }
  }
}
</script>

后端代码：

const express = require('express')
const multer = require('multer')
const jwt = require('jsonwebtoken')
const app = express()

const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, 'uploads')
  },
  filename: function (req, file, cb) {
    cb(null, file.fieldname + '-' + Date.now())
  }
})

const upload = multer({ storage: storage })

app.post('/upload', verifyToken, upload.single('file'), (req, res, next) => {
  res.json({ message: 'File uploaded successfully' })
})

function verifyToken(req, res, next) {
  const token = req.headers.authorization.split(' ')[1]
  if (!token) {
    return res.status(401).send('Unauthorized request')
  }
  try {
    const decodedToken = jwt.verify(token, 'secret')
    req.userData = decodedToken
    next()
  } catch (error) {
    return res.status(401).send('Unauthorized request')
  }
}

app.listen(3000, () => {
  console.log('Server started on port 3000')
})

核心代码：

前端代码中的`Authorization`头部是用于携带token的，后端代码中的`verifyToken`函数用于验证token是否有效。

headers: {
  Authorization: `Bearer ${token}`
}

function verifyToken(req, res, next) {
  const token = req.headers.authorization.split(' ')[1]
  if (!token) {
    return res.status(401).send('Unauthorized request')
  }
  try {
    const decodedToken = jwt.verify(token, 'secret')
    req.userData = decodedToken
    next()
  } catch (error) {
    return res.status(401).send('Unauthorized request')
  }
}