Mongodb和Gridfs文件下载

Question

I'm building an application that allows the user to upload and download files. The issue i'm currently having is that I can retrieve the file from my MongoDB database and download it locally through my machine, but I can't get it to download through the browser.

So far I have tried doing it like this

const conn = mongoose.createConnection(process.env.URL, {
    useNewUrlParser: true,
    useUnifiedTopology: true
})

const bucket = new GridFSBucket(conn, {bucketName: 'uploads'});


router.get('/download', (req, res) => {

    const files = bucket.openDownloadStreamByName('3987a162969935378c4f8cbe5d95bb46.svg').pipe(fs.createWriteStream('./3987a162969935378c4f8cbe5d95bb46.svg'))
    res.end()
})

Answer 1

I do not think the issue is with mongoDB or Gridfs its how you are dealing with the file stream. If you want the file to be downloaded once the user calls /GET /download you need to
use - res.download(file); eg

 const conn = mongoose.createConnection(process.env.URL, { useNewUrlParser: true, useUnifiedTopology: true }) const bucket = new GridFSBucket(conn, { bucketName: 'uploads' }); router.get('/download', (req, res) => { const files = bucket.openDownloadStreamByName('3987a162969935378c4f8cbe5d95bb46.svg').pipe(fs.createWriteStream('./3987a162969935378c4f8cbe5d95bb46.svg')) res.download(files) })

Good Luck! Also visit this Download a file from NodeJS Server using Express

Answer 2

If we want to send file directly to client without writing to disk, use this:

backend

router.get('/download', (req, res) => {
  res.set('Content-disposition', `attachment; filename="your_file_name.svg"`);
  res.set('Content-Type', 'image/svg+xml');
  bucket.openDownloadStreamByName('your_file_name.svg').pipe(res);
})

frontend

fetch('http://localhost:8000/download')
      .then(res => res.blob())
      .then(data => {
        saveAs(data, 'your_file_name.svg');
      })