The person who wrote this Spotify p2p software also wrote uTorrent, which was bought by the company bittorrent after they struggled to make a C++ client on their own. The original bittorrent implimentation was in python, but they re-skinned uTorrent as bittorrent and shipped both for a few years. https://en.wikipedia.org/wiki/Ludvig_Strigeus

https://www.csc.kth.se/~gkreitz/spotify/kreitz-spotify_kth11...

KTH link is better than scribd for downloading. though academic links are sometimes prone to link rot.