Cache Control Directives Demystified

Many years ago, HTTP 1.1 introduced specialized Cache Control directives to control the behavior of browser caches and proxy caches. These were a refinement over the HTTP 1.0 headers that programmers were using to control the behavior of caches. Though these directives are several years old, we still see them being used incorrectly. In this article, we explain the meaning and relevance of the most important cache control directives.