app.js

/**
 * Module dependencies.
 */

require.paths.unshift(__dirname + '/vendor/');

var express   = require('express'),
    keys      = require('keys'),
    fs        = require('fs'),
    formidable = require('formidable');
    var util = require('util');

var app = module.exports = express.createServer();
app.store = new keys.Memory();

// Configuration

app.configure(function( ){
  app.set('views', __dirname + '/views');
  app.set('view engine', 'jade');
  app.use(express.bodyParser());
  app.use(express.methodOverride());
  app.use(express.cookieParser());
  app.use(app.router);
  app.use(express.static(__dirname + '/public'));
});

app.configure('development', function( ){
  app.use(express.logger());
  app.use(express.errorHandler({ dumpExceptions: true, showStack: true }));
});

app.configure('production', function( ){
  app.use(express.logger());
  app.use(express.errorHandler());
});

// Routes

app.get('/', function( req, res ){
  res.render('new');
});

app.post('/songs', function( req, res ){
  res.render('create', {
    path:        req.body.song.path,
    description: req.body.song.description
  });
});

app.post('/upload', function( req, res ){
  uploadFile(req, res);
});

app.get('/uploads/:uid', function( req, res ){
  readSession(req, 'progress', function( err, buf ){
    if ( buf ) {
      res.writeHead(200, {'Content-Type': 'application/json'});
      res.write(JSON.stringify({ progress: buf.toString() }));
      res.end();
    } else {
      writeSession(req, 'progress', '0');
      readSession(req, 'progress', function( err, buf ){
        if ( buf ) {
          res.writeHead(200, {'Content-Type': 'application/json'});
          res.write(JSON.stringify({ progress: buf.toString() }));
          res.end();
        } else {
          res.send('Not Found', { 'Content-Type': 'text/plain' }, 404);
        }
      });
    }
  });
});

// Upload

function uploadFile( req, res ) {
        util.debug('this is a form request');

        //setup this form receiver
        var form = new formidable.IncomingForm();
        var bytesTotal  = req.headers['content-length'],
            bytesReceived = 0,
            fileName      = null,
            fileStream    = null;

        form.encoding = 'utf-8';
        form.keepExtensions = true; //keep extensions
        form.maxFieldsSize = 0.5 * 1024 * 1024; //max memory allocated of a field in bytes
        
        /*
        form.on('field', function(name, value) {
            util.debug('received field: ' + name + ' = ' + value);
        });

        form.on('fileBegin', function(name, file) {
            util.debug('fileBegin');
        });

        form.on('error', function(err) {
            util.debug('error: ' + err);
        });
        form.on('end', function() {
            util.debug('stream end.');
        });
        */

        //handle every part
        form.onPart = function(part) {
            var dirName = createUploadDirectory(req);
            fileName    = part.filename.split(/\\/).reverse()[0];
            fileName    = dirName + '/' + fileName;
            fileStream  = fs.createWriteStream(fileName);
            writeSession(req, 'path', fileName.replace('./public', ''));

            fileStream.addListener("error", function(err) {
              util.debug(err);
            });

            fileStream.addListener("drain", function() {
              req.resume();
            });

            //handle chunks of files
            part.on('data', function(chunk) {
                //util.debug('received / expected: ' + form.bytesReceived + ' / ' + form.bytesExpected + ' (after chunk, size: ' + chunk.length);
                req.pause();

                fileStream.write(chunk, 'binary');
                bytesReceived += chunk.length;

                var progress = Math.round( (bytesReceived / bytesTotal * 100) ).toString();
                writeSession(req, 'progress', progress);
            });

            //handle part end
            part.on('end', function() {
                util.debug('part end.');
                fileStream.end();
                req.resume();
                writeSession(req, 'progress', '100');
                uploadComplete(req, res);
            });
            //form.handlePart(part);
        };

        //start parsing this stream
        form.parse(req);
}

function createUploadDirectory( req ) {
  var uid      = req.param('uid'),
      dirName  = "./public/songs/" + uid;
  req.pause();
  fs.mkdir(dirName, '744', function( ) { req.resume(); });

  return dirName;
}

function writeSession( req, key, value ) {
  app.store.set(sessionKeyFor(req, key), value);
}

function readSession( req, key, fn ) {
  app.store.get(sessionKeyFor(req, key), fn);
}

function clearSession( req ) {
  app.store.clear();
}

function sessionKeyFor( req, key ) {
  var uid = req.param('uid');
  return 'uploads.' + uid + '.' + key;
}

function uploadComplete( req, res ) {
  readSession(req, 'path', function( err, buf ){
    res.render('uploaded', {
      layout: false,
      path:   buf.toString()
    });
  });
}

// Only listen on $ node app.js

if (!module.parent) {
  app.listen(3000);
  console.log("Express server listening on port %d", app.address().port);
}