One of the old ways noxiousnet made money was allowing players to upload custom sound files with a chat text trigger for a small fee.
This was eventually reworked due to download sizes becoming too big. It was later replaced with a system that dynamically downloaded the files from the web during the game, and cached them in your data folder.
This repo is the old sound uploading and approval system, hastily written in terrible PHP code circa 2012, way before I remade the entire noxiousnet site in Node.js
It's probably best you don't directly copy paste the code but it's there for anyone curious.