Similar to all my TileCache setups, I treat caching as a secondary task, outside of TileCache’s domain. Because most data is updated at regular intervals, it is far easier for the server admins to configure the caching than it would be to bake that functionality into TileCache.

During testing, such caching would inappropriate, because the tiles that were there would have been changing regularly, and I didn’t want to have to clear my browser cache every time I made a small change in the code.

I’m still not convinced that my code is at all right — once I am, I’ll change the demo to live on the main TileCache server that MetaCarta hosts — so until that happens, I’m not adding caching headers because it makes my life more difficult, rather than for any other reason.