I'm fetching links from a webpage via LWP, LWP::UserAgent, and HTML::LinkExtor, and I've run into something I can't figure out.

How do I avoid fetching "duplicate" links, which are actually fragments at the end of a valid page in my queue? Is there a way to tell that the following three links are the same page, minus the fragment?

   http://www.foo.bar/index.html
   http://www.foo.bar/index.html#foo
   http://www.foo.bar/index.html#bar
[download]

I pass these into my @links array, and remove the dupes with the following:

   my @pri = grep {!$seen{$_} ++} @links;
[download]

The problem is that the "uniqueness" is on a stringification level, not at the URI level, so fragments which differ make the URL seen as unique. I'd much rather prefer not to fetch the same page 20 times for a link which appears once, with 20 fragments on it.

Should I split on the '#' there, and fetch everything to the left of it?

What if someone decides to put the '#' in a query string? Is that possible?