Request closed and no one error event is emmited

I have a this sample

'use strict';

const express = require('express'),
  Busboy = require('busboy'),
  bodyParser = require('body-parser'),
  app = new express()
  ;

app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());

app.post('/upload', function (req, res, next) {

  const busboy = new Busboy({ headers: req.headers });

  busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {

    file.on('data', function(data) {
      console.log('File [' + fieldname + '] got ' + data.length + ' bytes');
    });

    file.on('close', function() {
      console.log('File [' + fieldname + '] Closed');
    });

    file.on('error', function() {
      console.log('File [' + fieldname + '] Errored');
    });

    file.on('end', function() {
      console.log('File [' + fieldname + '] Finished');
    });

    const fStream = require('fs').createWriteStream(require('path').join(__dirname, 'tmp'));

    fStream.on('finish', function () {
      console.log('File stream for [' + fieldname + '] Finished');
    });

    fStream.on('end', function () {
      console.log('File stream for [' + fieldname + '] End');
    });

    fStream.on('close', function () {
      console.log('File stream for [' + fieldname + '] Closed');
    });

    fStream.on('error', function () {
      console.log('File stream for [' + fieldname + '] Errored');
    });

    file.pipe(fStream);

  });

  req.on('close', function() {
    console.log('Request closed');
    res.send('Closed');
  });

  busboy.on('error', function() {
    console.log('Busboy error');
    res.send('Finished');
  });

  busboy.on('close', function() {
    console.log('Busboy close');
    res.send('Finished');
  });

  busboy.on('finish', function() {
    console.log('Request finished');
    res.send('Finished');
  });

  req.pipe(busboy);

});

app.listen(3000);

Whn I tried do this curl -F "image=@/tmp/test/big_file.jpg" --limit-rate 128k http://192.168.0.105:3000/upload and after a few seconds press Ctrl+C I had in console something like this

File [image] got 16384 bytes
File [image] got 16384 bytes
File [image] got 16384 bytes
File [image] got 16384 bytes
File [image] got 16384 bytes
File [image] got 16384 bytes
Request closed

And that’s all. No one error messages. How do I need to catch event where request is terminated from a client?

[mscdex]

@ValYouW I’m not sure it matters. The stream objects (both req and busboy) will just get GC’ed at some point anyway, so calling req.unpipe(busboy) on 'aborted' doesn’t really gain you much since nothing else will happen with req after it’s aborted.

[Muqito]

Correct me if I am wrong, but the file is just a ReadableStream; and a ReadableStream stops piping when it receives null.

If you received a file and the request is being closed you can just remove the output path of the WriteableStream. The readstream won’t emit an error since it’s just waiting for more data. There is no problem for a ReadableStream to wait 10 seconds or even longer before it receives data. Same with a WriteableStream.

If they can’t pipe to eachother they just buffer up in the memory until they can.

So an event on the request is the way to go. Don’t get me wrong; I completely understand why “this would be easier” for your codebase. But it has nothing to do with a ReadableStream error that the file actually is.

But if you want to track how much progress you have done and at what % you stopped the request; you can store expectedData from request headers like this:

let expectedData = req.headers['content-length'];

and in your file on data-event; you can track your fetched data by adding data.length to a fetchedData variable like this:

fetchedData += data.length;

If you want to know more about streams; I would suggest this handbook:

Substack’s stream handbook on github