You can, in fact, use LWP to load just the first part of the GET request, by using a content-callback handler that throws an exception, cutting off any further action. Quoting from perldoc LWP::UserAgent:

The request can be aborted by calling die() in the call- back routine. The die message will be available as the "X-Died" special response header field.

-- Randal L. Schwartz, Perl hacker