如何使用Node.js和Express实现Web应用程序中的文件上传

.
├── app.js
├── package.json
├── bin
│   └── www
├── package.json
├── public
│   ├── images
│   ├── javascripts
│   └── stylesheets
│       └── style.css
├── routes
│   ├── index.js
│   └── users.js
├── views
│   ├── error.pug
│   └── index.pug
│   └── layout.pug

npm install express-fileupload
npm install node-fetch@^2.6.6
npm install form-data

extends layout

block content
  h1= title
  p 欢迎来到#{title}

  <form action="/upload" method="POST" enctype="multipart/form-data">
    <input type="file" name="file" required>
    <button type="submit">上传</button>
  </form>

const express = require('express');
const fetch = require('node-fetch');
const fileUpload = require('express-fileupload');
const FormData = require('form-data'); 
const fs = require('fs');
const router = express.Router();

router.use(fileUpload({
  // 配置文件上传，最大文件大小为10MB
  limits: { fileSize: 10 * 1024 * 1024 },

  // 将上传的文件暂时存储到磁盘，而不是在内存中缓冲
  useTempFiles : true,
  tempFileDir : '/tmp/'
}));

router.post('/', async function(req, res, next) {
  if (!req.files || !req.files.file) {
    return res.status(422).send('未上传文件');
  }

  const uploadedFile = req.files.file;

  // 将文件的信息打印到控制台
  console.log(`文件名：${uploadedFile.name}`);
  console.log(`文件大小：${uploadedFile.size}`);
  console.log(`文件MD5哈希：${uploadedFile.md5}`);
  console.log(`文件Mime类型：${uploadedFile.mimetype}`);

  // 使用Verisys Antivirus API扫描文件中的恶意软件 - 相同的概念可以用于以不同的方式处理上传的文件
  try {
    // 将上传的文件附加到一个FormData实例
    var form = new FormData();
    form.append('file_name', uploadedFile.name);
    form.append('file', fs.createReadStream(uploadedFile.tempFilePath), uploadedFile.name);

    const headers = {
      'X-API-Key': '<YOUR API KEY HERE>',
      'Accept': '*/*'
    };

    // 将文件发送到Verisys Antivirus API
    const response = await fetch('https://eu1.api.av.ionxsolutions.com/v1/malware/scan/file', {
      method: "POST",
      body

: form,
      headers: headers
    });

    // 我们从API获取到了响应吗？
    if (response.ok) {
      const result = await response.json();

      // 文件包含病毒/恶意软件吗？
      if (result.status === 'clean') {
        return res.send('上传成功！');
      } else {
        return res.status(500).send('上传的文件包含恶意软件！');
      }
    } else {
      throw new Error('无法扫描文件：' + response.statusText);
    }
  } catch (error) {
    // 将错误转发给Express错误处理程序
    return next(error);
  } finally {
    // 删除上传的临时文件
    fs.rm(uploadedFile.tempFilePath, () => {});
  }
});

module.exports = router;

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');

var indexRouter = require('./routes/index');
var usersRouter = require('./routes/users');
var uploadRouter = require('./routes/upload');

var app = express();

// 设置视图引擎
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', indexRouter);
app.use('/users', usersRouter);
app.use('/upload', uploadRouter);

// 捕获404并转发到错误处理程序
app.use(function(req, res, next) {
  next(createError(404));
});

// 错误处理程序
app.use(function(err, req, res, next) {
  // 仅在开发环境提供错误信息
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // 渲染错误页面
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;