formidable form file upload

formidable-form-file-upload.js

var express = require('express');
var formidable = require('formidable');

var app = express.createServer();

var AppController = {};

// AppController is synonym for another file's module.exports
AppController.uploadFile = function(req, res, next) {
    var form = new formidable.IncomingForm();
    form.uploadDir = '/tmp';
    
    form.on('file', function(field, file) {
        var dst = path.join('uploads', req.user._id.toString());
        
        // here you can save to req.body some file specifics
        // such as dst file path and etc...
        // to be able to plug it into nex middleware and reuse
        
        // you can refactor this function to a constructor that returns a function
        // with specific upload basedir
        // or rather yet upload basedir callback

        fs.createReadStream(file.path)
        .pipe(fs.createWriteStream(dst))
        .on('error', next.bind(null))
        .on('finish', function() {
            // ... same as above
            // remove original file
            fs.unlink(file.path);
            next();
        });
    });

    form.on('field', function(field) {
        console.log([].slice.call(arguments));
    });

    form.on('error', next.bind(null);
    
    form.parse(req);
};

app.route('/upload')
    .post(AppController.uploadFile);

app.listen(3000);