09-09-2012, 09:03 AM
Oh, I don't think you will have to at all. No matter what, when a map starts or you connect, the server tells your client about two things basically: the map's file name and the url where you can download it. The client checks if it has that filename loaded, and if it doesn't it checks the dlcache, and if it's not there it downloads the map with the provided url. (I'm probably simplifying it a little.) PK3s and files in your data directory are loaded on start so you don't have to worry about them being redownloaded.