Auto-updater + node-webkit

I'm looking a solution to automatically download an update to the latest version of game via in-app as node-webkit.

I won't deliver the new version of game as package to make the users download again... constantly.

Isn't possible to implement auto-updater?

I tought it's not possible to do with offline cache file.

I made this thing where it checks for updates, and notifies the Player if there is an update, but I cant get it to download.