Hello,
I have not seen the situation, when HTTP server was caching uploaded file, and next uploads the same file didn't write the old version. What exactly you mean when say "cache system"? Often, proxy servers don't accept HTTP headers for example "Cache-Control: no-cache", and client received cached results, brouser also can show cached pages, while you don't clear the cache. But, caching at uploading files I didn't see.
Please, send me more detailed specification of this project.
Thanks