Re: Ideas for implementing download links that expire, via e-mails

That's overly complicated. Just include the timestamp the link expires on plus a hash code based on the timestamp, like follows:

use strict;
use warnings;

my ($url, $key, $exp, $hash, $link);
$url = 'http://www.domain.com/folder/page.html';
$key = 'm239VdSn';

$exp = time() + 60*60*24;
$hash = crypt(substr($exp,-8,8),$key);
$hash = substr($hash, 2);
$hash =~ s/[^a-zA-Z0-9]//g; $hash = uc($hash);

$link = "$url?$exp-$hash";
print $link;
[download]

Note that crypt only works on the first 8 characters of the given text, so you want to feed it the last 8 characters of the timestamp. The modifications to the resulting hash were to make the link look prettier.

EDIT: Added a line to remove the first two characters of the hash, which when using crypt, contain the salt.

Comment on Re: Ideas for implementing download links that expire, via e-mails Download Code

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Re^2: Ideas for implementing download links that expire, via e-mails by Fletch (Bishop) on Apr 22, 2005 at 14:49 UTC
`$hash =~ s/[^a-zA-Z0-9]//g;` [download] ITYM `$hash =~ y/a-zA-Z0-9//cd;` HTH. HAND. `$ perl -MBenchmark=cmpthese -le 'cmpthese( 500_000, { s => sub { $_ = +q{123#$%abc^&DEF}; s/[^a-zA-Z0-9]//g }, y => sub { $_ = q{123#$%abc^ +&DEF}; y/a-zA-Z0-9//cd; } } )' Rate s y s 174825/s -- -80% y 862069/s 393% --` [download]	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^2: Ideas for implementing download links that expire, via e-mails
by Fletch (Bishop) on Apr 22, 2005 at 14:49 UTC

$hash =~ s/[^a-zA-Z0-9]//g;
[download]

ITYM $hash =~ y/a-zA-Z0-9//cd; HTH. HAND.

$ perl -MBenchmark=cmpthese -le 'cmpthese( 500_000, { s => sub { $_ = 
+q{123#$%abc^&*DEF}; s/[^a-zA-Z0-9]//g }, y => sub { $_ = q{123#$%abc^
+&*DEF}; y/a-zA-Z0-9//cd; } } )'
      Rate    s    y
s 174825/s   -- -80%
y 862069/s 393%   --
[download]

[reply]
[d/l]
[select]