Express example using busboy stream to GridFS

Busboy_gridfs.js

var uploader = function(req, res) {

  var busboy = new Busboy({ headers: req.headers });
  busboy.on('file', function(fieldname, stream, filename, encoding, contentType) {

    var pStream = pauseStream(); // use pause stream to have time to open the GridStore
    stream.pipe(pStream.pause());

    console.log('POST ' + req.originalUrl + ' File: '+ filename + ' Field: ' + fieldname);
    cntProcessingFiles++;

    new GridStore(db, null, filename , 'w', {content_type:contentType}).open(function(err, gridFile) {
      if(err) console.log(err);

      gridFile.on('close', function() {
        gridFile.close(function(err, data) {
            cntProcessingFiles--;
            // do something with the gridfile
          });
        });
      });

      pStream.pipe(gridFile);
      pStream.resume();
    });
  });

  // form error (ie fileupload-cancel)
  busboy.on('error', function(err) {
    console.error(err);
    res.send(500, 'ERROR', err);
  });


 // all uploades finished
 function end() {
   // wait until all files are finished
   if(cntProcessingFiles > 0) {
     setTimeout(end, 200);
     return;
   }

   if(res.finished) return;

	res.send('all done');

 }
 busboy.on('end', end);

 // start parsing the HTTP-POST upload
 req.pipe(busboy);
};


app.post('/upload', uploader);

@tk2, this should be defined like this:

var pauseStream = require('pause-stream');

Please don't forget to install this module first, or put this package as a dependency in your package.json file.

;)