I'd definitely use DB_File for this - zengargoyle's suggestion of Cache::FileCache is not bad either, but a DBM file probably beats it in this case. Something like 
use DB_File;
use constant PACKFMT => "LI";

sub exit_limit_enforced { print(<<"EOT"), exit }
Content-type: text/html

<html>
<head>
<title>Traffic control limit reached</title>
</head>
<body>
$_[0]<br />
Your IP: $ip<br />
Last visit: $time<br />
Number of Visits: $visits
</body></html>
EOT

tie my %limit, 'DB_File', './data/rsn_users.dbm';

my $ip = $ENV{REMOTE_ADDR};

my ($time, $visits) = exists $limit{$ip}
    ? unpack PACKFMT, $limit{$ip}
    : (time() - 21, 0);

$visits = 0 if $time < time() - 86400;

exit_limit_enforced("You reloaded too soon!")
    if $time > time() - 20;

exit_limit_enforced(
    "You are over the allowed number of visits per day!<br />"
    . "You may not visit again before" . localtime($time + 86400)
) if $visits > 15;

$limit{$ip} = pack PACKFMT, $time, $visits;

untie %limit;

[download]

Makeshifts last the longest.

In reply to Re: When does XML get to be too much? by Aristotle
in thread When does XML get to be too much? by newrisedesigns

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.