Proxy server with content filtering support?

Question

I'd like to run a proxy server in which I can manipulate the transmissions if needed. For a basic example, if the proxy client requests paypal.com I would want to deny the request entirely. For a more advanced example, if a client requests certain pages, I'd like to manipulate what is actually returned in terms of HTML (want to have some fun).

Does anyone know of any open source solutions that will either let me do this out of the box, or with as little coding as possible?

Answer 1

The open source project I know closest that what seems to what you want is Squid proxy plus DansGuardian. It will allow you to block pages based on page content, url filtering and other tricks. It uses plenty of resources though, be prepared.