Monitor squid proxy performance (throughput)

[bondbig]

Hello everyone!
I've zabbix 1.6 and several monitored servers, two of them are Squid Proxy (2.4 Stable7). I want to run some task (each 5 min, for ex), which immitates user activity (maybe a GET request) on proxy and measures server throughput.
How can i implement such a check?

[richlv]

web monitoring would be ideal for this task... if only it supported custom http proxies for individual checks