#!/usr/bin/perl -T
#
# the main page.  /cgi-bin/main.pl
#
use strict;
use warnings;
use CGI;

my $q = new CGI;
my $cookie = $q->cookie( -name => 'session_id' )
    || set_and_test_cookie( $q );

# if you get here, you have a cookie
#  use cookie for whatever...

exit;

sub set_and_test_cookie {
  my $q = shift;
  my $server = $q->server_name;
  my $session_id = $ENV{UNIQUE_ID};  # change to taste
  my $cookie = $q->cookie(
    -name => 'session_id',
    -value => $session_id,
    -path => '/cgi-bin',
    -secure => 1,
  );
  print $q->redirect(
    -url => "https://$server/cgi-bin/cookie_test.pl",
    -cookie => $cookie,
  );
  exit;
}
#
# end main.pl
#

#!/usr/bin/perl -T
#
# check the cookie.  /cgi-bin/cookie_test.pl
#
use strict;
use warnings;
use CGI;

use constant SOURCE_CGI => "/cgi-bin/main.pl";

my $q = new CGI;
my $cookie = $q->cookie( -name => 'session_id' );

if ( defined $cookie ) {
  print $q->redirect( -url => SOURCE_CGI ); # ok, go back.
} else {
  print $q->header( -type => 'text/html' ),
    $q->start_html( "Cookies Disabled" ),
    $q->h1( "Cookies Disabled" ),
    $q->p( "Your browser is not accepting cookies.  You need them. Enable them and ", $q->a( { -href => SOURCE_CGI }, "Try Again" ), '.' ),
    $q->end_html;
}

# end cookie_test.pl