Here is a small issue: https://github.com/claudiodangelis/qr-filetransfer/blob/mast...

I don't know if it is the barcode scanner app (I use the one from zxing, a very popular choice), or the Android implementation (LG, Android 7), but here is a description of what happens:

As soon as I scan the barcode, it is copied to the clipboard. Then something goes to check if the URL is working (the barcode app? android clipboard? not sure). Since you exit after the first request, my browser never gets the chance to download the file. If I remove the os.Exit(), I get it working (and then terminate qr-filetransfer via ctrl+c).

Anyhow, very nice work. Kudos!