Compressing File Uploaded From Multer using Nodejs Zlib

Question

I am trying to compress an uploaded file using nodejs zlib.The compression works but trying to uncompress it throws an error.I created a compress route which is a post request to upload the file to be compressed:

app.post('/compress', upload.single('file'), (req, res) => {
  try {
    var streamInstance = new stream.Readable();
    const destination = createWriteStream(`compressed/${req.file.originalname}.gz`);
    const source = streamInstance.push(Buffer.from(JSON.stringify(req.file)))
    res.json(source)
    streamInstance.push(null);
    pipeline(source, gzip, destination, (err, file) => {
      if (err) {
        console.log(err)
        return res.json('An error occurred:', err);
      } else {
        console.log({
          file: file
        })
        return res.json(file)

      }
    })
  } catch (err) {
    console.log(err)
    res.json(err)
  }
})

This add the compressed file in the compressed directory but trying to uncompress it throws an error.

Is there another method i could use in compressing this file using zlib?

Answer 1

Multer gives the ability to use the memoryStorage method.So you can get the actual buffer of that file.With that you can use this:

var storage = multer.memoryStorage()
var upload = multer({
  storage: storage
})

app.post('/compress', upload.single('file'), async (req, res) => {
  try {
    const destination = `compressed/${req.file.originalname}.gz`;
    await zlib.gzip(req.file.buffer, async (err, response) => {
      if (err) {
        return res.status(500).json({error:err})
      } else {
        await fs.appendFile(path.join(__dirname,destination), response, (err, data) => {
          if (err) {
            return res.status(500).json({error:err})
          } else {
            res.download(path.join(__dirname,destination),`${req.file.originalname}.gz`);
          }
        })
      }
    })
  } catch (err) {
    console.log(err)
    res.json(err)
  }
})