Tag: code

ClickBank Instant Notification Service in Perl

ClickBank is generous to provide code examples for many implementations of their Instant Notification Service, but… they don’t include Perl for some reason.

Here’s my Perl implementation.

use CGI;
use Digest::SHA1 qw(sha1_hex);
use Encode;

$q = new CGI;

sub ipnVerification() {
  my $secretkey = 'YOUR SECRET KEY';
  my $pop = "";

  foreach $field (sort($q->param))
  {
   unless ($field eq "cverify") {
      $pop .=  $q->param($field) . "|";
    }
  }
  $pop .= $secretkey;
  my $calcedVerify = sha1_hex(encode("utf8", $pop));
  $calcedVerify = uc(substr($calcedVerify,0,8));
  return ($calcedVerify eq $q->param("cverify"));
}

Enjoy!