Volta is a high performance, low resource URI rewriter for use with the
Squid caching proxy server (http://www.squid-cache.org) With it, you
can dynamically alter URI requests that pass through Squid based on
various criteria.

It uses a state machine to parse URIs and rules, and a constant
database to store and access those rules. It can then either perform
conditional rewrites internally, or by evaluating Lua scripts.