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?

In reply to Avoid "duplicate" fetching with LWP by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.