You'll want to modify your check_url function so that it accepts a URL or a list of URLs as an argument; then you're not depending on a global variable.

You may also want to take the error-handling and error-invocation out of the subroutine (since it sounds like you're moving the subroutine into a library of some sort) and let your application code deal with the error.

Personally, I'd change the subroutine to accept a list of valid referrers and a URL to check, then return either 1 for a good url or 0 (or undef) for a bad URL.

Something like this: 

    sub check_url {
        local $_ = shift;
        my $valid_referrers = shift;

        my $valid = join '|', @$valid_referrers;
        return /$valid/ ? 1 : 0;
    }

[download]
You can use this something like this: 
    my @referrers =
       ('http://www.foo.com/',
        'http://www.bar.com/');

    my @urls_to_check = 
       ('http://www.baz.com/bar/',
        'http://www.foo.com/bar/');

    for my $url (@urls_to_check) {
        print $url, ": ", check_url($url, \@referrers), "\n";
    }

[download]

In reply to Re: how to use require function with @referer URLs by btrott
in thread How do I make my script behave differently based on the referring URL? 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.