While developing myDrumPad, I came across an interesting problem for my in-app purchase support. The app allows users to download additional packs of sounds (referred to as “sound packs” in the app) that they can use to tap out songs and rhythms. The sound packs themselves were a collection of CAF-encoded uncompressed PCM audio files, with a single configuration file describing the labels and arrangement of the sound files on the drum pad’s grid of buttons.
I wanted to be able to add additional sound packs without issuing a new release of the app, but since the information describing the sound packs is largely static, I didn’t want to have to worry about maintaining a dynamic server for the app to continue functioning. I wanted it to largely be “fire and forget”.
What I came up with is, I think, a best of both worlds. The app functions without needing me to maintain a server, but I can still dynamically add additional resources to the app instantly. Read on to find out more.