I use Nagios at work and at home, but WebInject:

http://www.webinject.org/
http://sourceforge.net/projects/webinject/
https://github.com/sni/Webinject

might contain what you're looking for.

Troy Johnson 

---
Ok, before I go write one myself, does anyone know of a simple website uptime
monitoring tool? Yeah, I can use Nagios but that's waaayyy overdone and
waaaaayyy overcomplicated.
All I need is something I can give a list of websites (or URLs), have it do an
HTTP connection to, possibly look for a string in the resulting webpage and let
me know "Hey that worked" or "Hey I got a HTTP/200 but that string wasn't
there" or "Hey it won't even talk on port 80". Be nice if it can represent the
output as HTML and allow to setup some email alerts, but producing a nice
processable text result would be enough.
---