mod_rest_cache is an extension module to the Apache 2 web server. Its purpose is to provide a mechanism to store content in a local disk cache that has been retrieved from another web server (or 2nd tier), and to provide a REST-like HTTP interface to remove specific items from that cache.
The module relies on mod_rewrite to control the decision making process over whether to retrieve content from the local cache or from the 2nd tier, and relies on mod_proxy to perform the task of retrieving content from the 2nd tier when necessary.