#!/usr/local/bin/perl -w
# cgi-s-cookie.pl -- Zustandserhaltung mit Cookies.

use strict;
use CGI qw(:standard);
use CGI::Cookie;

my $state      = retrieve_state();
my $nextstate  = compute_next_state($state);
my $saveaction = save_state($nextstate);

# Tue etwas abhaengig von $state:
print header(-cookie => $saveaction),
    start_html('State with Cookies'),
    "Current state: ", $state, p,
    "If you call me again, I'll increment it for you",
    end_html;

use constant INITSTATE => 1;
use constant STATENAME => 'mystate';
sub retrieve_state {
    my $state = cookie(-name => STATENAME) || INITSTATE;
    return $state;
}

sub compute_next_state {
    my $current_state = shift;
    return $current_state + 1;
}

sub save_state {
    my $newstate = shift;
    my $cookie   = new CGI::Cookie(-name     => STATENAME,
                   -value    => $newstate,
                       -expires  => '+5m');
    return $cookie;
}