Add a stop or abort method

Right now the only way I have found to stop a file form uploading is to call busboy._parser.parser._ignore(). It would be great if you exposed some sort of abort method.

Use case: you want to do some validation on the image, but as soon as the image is not valid, stop uploading the image and return the error to the client. If you’re uploading a 1 gig image and you can figure out 1/4 of the way through parsing it that it’s the wrong width then it’s much better to stop then as opposed to making the user wait until finish event is called.

Example pseudoish code of I’d like to do:

if (self.req.method === 'POST') {
    var busboy = this.busboy = new Busboy({
        headers: self.req.headers
    });

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

            if(IMAGE IS THE WRONG WIDTH) {
                busboy.abort();
            }

            if(IMAGE IS THE WRONG DPI) {
                busboy.abort();
            }

            if(IMAGE IS THE WRONG SOMETHING ELSE) {
                busboy.abort();
            }

        });
    });

    busboy.on('aborted', function() {
        // DO SOMETHING HERE ... maybe return error to the client
    });
}

[Kikketer]

@mscdex So this is what I have:

    var busboy = new Busboy({
      headers: req.headers,
      limits: {
        files: 1,
        fileSize: 1024
      }
    });
    var saveTo = path.join(__dirname, '../teamPhotos', req.params.id + '.jpg');

    busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {
      file.on('limit', function() {
        console.log('limit reached!');
        req.unpipe(busboy);
        res.status(500).end('Limit Reached');  // Not doing anything...
      });
      file.pipe(fs.createWriteStream(saveTo));
    });
    busboy.on('finish', function() {
       res.writeHead(200, {'Connection': 'close'});
       res.end();
    });

    // This doesn't work without piping here, but also always returns 200
    return req.pipe(busboy);

Also I was wrong, 200 isn’t returned. It’s just sitting in pending (never returning). Is there a nice way to end the pipe with the exception? .end() ?

Ok so dur… it was just my status bit I had incorrect:

req.unpipe(busboy);
res.writeHead(500, {'Connection': 'close'});
res.end('Limit Reached');

Thanks

[mscdex]

A better solution though to avoid processing unnecessary data might be to do something like:

self.req.unpipe(busboy);
// `Connection: close` is important here, to ensure the socket is closed after
// we write our response.
self.res.writeHead(400, { 'Connection': 'close' });
self.res.end();