Hi Ashish,
Mojito uses express underneath. "req.files" contain information about the files uploaded. There are few articles/blog posts that go into the details. One of them is http://www.hacksparrow.com/handle-file-uploads-in-express-node-js.html
From Mojito, within a controller, you can get access to req.files like this:
index: function(ac) {
var req = ac.http.getRequest();
var files = req.files;
... your code to copy over the files...
}
Hope that helps!
- Raj