Using Sailsjs Skipper file uploading with Flowjs

Question

I'm trying to use skipper and flowjs with ng-flow together for big file uploading.

Based on sample for Nodejs located in flowjs repository, I've created my sails controller and service to handle file uploads. When I uploading a small file it's works fine, but if I try to upload bigger file (e.g. video of 200 Mb) I'm receiving errors (listed below) and array req.file('file')._files is empty. Intersting fact that it happening only few times during uploading. For example, if flowjs cut the file for 150 chunks, in sails console these errors will appear only 3-5 times. So, almost all chunks will uploaded to the server, but a few are lost and in result file is corrupted.

verbose: Unable to expose body parameter `flowChunkNumber` in streaming upload! Client tried to send a text parameter (flowChunkNumber) after one or more files had already been sent. Make sure you always send text params first, then your files.

These errors appears for all flowjs parameters.

I know about that text parameters must be sent first for correct work with skipper. And in chrome network console I've checked that flowjs sends this data in a correct order.

Any suggestions?

Controller method

upload: function (req, res) {
  flow.post(req, function (status, filename, original_filename, identifier) {
    sails.log.debug('Flow: POST', status, original_filename, identifier);
    res.status(status).send();
  });
}

Service post method

$.post = function(req, callback)  {

var fields = req.body;
var file = req.file($.fileParameterName);
if (!file || !file._files.length) {
  console.log('no file', req);
  file.upload(function() {});
}
var stream = file._files[0].stream;

var chunkNumber = fields.flowChunkNumber;
var chunkSize = fields.flowChunkSize;
var totalSize = fields.flowTotalSize;
var identifier = cleanIdentifier(fields.flowIdentifier);
var filename = fields.flowFilename;

if (file._files.length === 0 || !stream.byteCount)
{
  callback('invalid_flow_request', null, null, null);
  return;
}

var original_filename = stream.filename;
var validation = validateRequest(chunkNumber, chunkSize, totalSize, identifier, filename, stream.byteCount);
if (validation == 'valid')
{

  var chunkFilename = getChunkFilename(chunkNumber, identifier);

  // Save the chunk by skipper file upload api
  file.upload({saveAs:chunkFilename},function(err, uploadedFiles){
    // Do we have all the chunks?
    var currentTestChunk = 1;
    var numberOfChunks = Math.max(Math.floor(totalSize / (chunkSize * 1.0)), 1);
    var testChunkExists = function()
    {
      fs.exists(getChunkFilename(currentTestChunk, identifier), function(exists)
      {
        if (exists)
        {
          currentTestChunk++;
          if (currentTestChunk > numberOfChunks)
          {
            callback('done', filename, original_filename, identifier);
          } else {
            // Recursion
            testChunkExists();
          }
        } else {
          callback('partly_done', filename, original_filename, identifier);
        }
      });
    };
    testChunkExists();
  });
} else {
  callback(validation, filename, original_filename, identifier);
}};

Edit

Found solution to set flowjs property maxChunkRetries: 5, because by default it's 0. On the server side, if req.file('file')._files is empty I'm throwing not permanent(in context of flowjs) error.

So, it's solves my problem, but question why it behave like this is still open. Sample code for flowjs and Nodejs uses connect-multiparty and has no any additional error handling code, so it's most likely skipper bodyparser bug.