Any update on this?
I have roughly 120+ items to download and clicking links one by one is not really acceptable nor appropriate.
If you want an example of how this is done right, have a look at DriveThruRPG and their downloader. You configure it with your creds, open it up and then just check the items you want to syncronise with your local storage. Job done, the app does the rest.
While not a standard web dev's job, it's not actually all that hard to build.