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const express = require('express');
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const multer = require('multer');
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const path = require('path');
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const fs = require('fs');
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const fsPromises = fs.promises;
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const morgan = require('morgan');
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// 创建 Express 应用实例
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const app = express();
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const PORT = 3000; // 可以根据需要修改端口
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// 设置文件存储配置
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const storage = multer.diskStorage({
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destination: async (req, file, cb) => {
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const uploadDir = 'uploads/';
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try {
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// 检查 uploads 目录是否存在，如果不存在，则创建它
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await fsPromises.mkdir(uploadDir, { recursive: true });
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cb(null, uploadDir); // 指定文件上传目录
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} catch (error) {
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cb(error);
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}
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},
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filename: (req, file, cb) => {
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cb(null, Date.now() + path.extname(file.originalname));
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}
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});
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// 创建上传实例，设置文件大小和类型限制
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const upload = multer({
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storage,
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limits: { fileSize: 5 * 1024 * 1024 }, // 限制文件大小为5MB
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fileFilter: (req, file, cb) => {
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const filetypes = /jpeg|jpg|png|gif|pdf/; // 允许的文件类型
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const extname = filetypes.test(path.extname(file.originalname).toLowerCase());
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const mimetype = filetypes.test(file.mimetype);
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if (mimetype && extname) {
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return cb(null, true);
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}
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cb(new Error('只允许上传 JPEG, PNG, GIF 和 PDF 文件'));
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}
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});
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// 中间件用于解析 JSON 和 URL 编码的数据
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app.use(express.json());
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app.use(express.urlencoded({ extended: true }));
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app.use(morgan('combined')); // 记录请求日志
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// 设置静态文件服务以提供前端页面
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app.use(express.static(path.join(__dirname, 'public')));
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// 定义文件上传接口
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app.post('/api/upload', upload.single('file'), (req, res) => {
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if (!req.file) {
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return res.status(400).json({ message: '没有文件上传' });
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}
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res.status(200).json({ message: '文件上传成功', filename: req.file.filename });
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});
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// 错误处理
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app.use((err, req, res, next) => {
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if (err instanceof multer.MulterError) {
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return res.status(400).json({ message: err.message });
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} else if (err) {
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console.error(err.stack);
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return res.status(500).json({ message: '服务器内部错误' });
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}
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next();
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});
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// 启动服务器
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app.listen(PORT, () => {
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console.log(`Server is running on http://localhost:${PORT}`);
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}); |
