如何使用mongoose通过multer上传文件？

npm install mongoose multer

const mongoose = require('mongoose');
const multer = require('multer');

const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, 'uploads/') // 上传文件的存储路径
  },
  filename: function (req, file, cb) {
    cb(null, file.originalname) // 上传文件的文件名
  }
});

const upload = multer({ storage: storage });

const fileSchema = new mongoose.Schema({
  filename: String, // 文件名
  path: String, // 文件路径
  size: Number, // 文件大小
  mimetype: String // 文件类型
});

const File = mongoose.model('File', fileSchema);

app.post('/upload', upload.single('file'), async (req, res) => {
  try {
    // 从multer中获取上传的文件信息
    const { filename, path, size, mimetype } = req.file;

    // 创建一个新的文件记录
    const file = new File({
      filename,
      path,
      size,
      mimetype
    });

    // 将文件记录保存到数据库中
    await file.save();

    res.status(200).send('File uploaded successfully');
  } catch (error) {
    res.status(500).send('Error uploading file');
  }
});

mongoose.connect('mongodb://localhost/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true })
  .then(() => {
    app.listen(3000, () => {
      console.log('Server started on port 3000');
    });
  })
  .catch(err => console.log(err));