How to know when to send a 304 Not Modified response

Question

I\'m writing a resource handling method where I control access to various files, and I\'d like to be able to make use of the browser\'s cache. My question is two-fold:

Answer 1

regarding cache-control:

You shouldn't have to worry about the cache-control when serving out, other than setting it to a reasonable value. It's basically telling the browser and other downstream entities (such as a proxy) the maximum time that should elapse before timing out the cache.