I'm trying to learn the limitations of CGI's using cookies and hidden fields through the use of CGI::Session. My main goal is to create a CGI that will call itself through multiple invocations of a form, getting further along each time. I'm having incredible difficulty with the main project, so I've created this simple script to test what I do (and don't) understand about session state.

This script simply asks for the user's name and age. It should loop each time the user submits, incrementing $age by one each time. Could someone please explain to me why this doesn't work past the 2nd invocation?

-fuzzyping

#!/usr/bin/perl

use strict;
use CGI;
use CGI::Session::DB_File;

my $title = "Test Hidden Fields";

my $cgi = CGI->new;
my $sid = $cgi->cookie('session_id') || undef;
my $Session = new CGI::Session::DB_File($sid, {FileName=>'/var/www/cgi
+-bin/nobody/sessions.db', LockDirectory=>'/var/www/cgi-bin/nobody'});
if ($sid) { $Session->load_param($cgi) }
$sid ||=$Session->id;
my $cookie = $cgi->cookie(-name=>'session_id', -value=>$sid, -expires=
+>"+5m");

print $cgi->header(
        -cookie=>$cookie,
        -start_html=>$title);
print "<center>",
        $cgi->h1($title),
        "</center>";

if ($cgi->param('name')) {
        $Session->param(-name=>'name', -value=>$cgi->param('name'));
        $Session->param(-name=>'age', -value=>$cgi->param('age'));
        $Session->save_param($cgi);
        &add_age;
} elsif ($cgi->param('test')) {
        &add_age;
} else {
        print $cgi->start_form,
                "Name: ",
                $cgi->textfield('name'),
                "Age: ",
                $cgi->textfield('age'),
                $cgi->p,
                $cgi->submit('Next'), " ",
                $cgi->defaults("Clear"),
                $cgi->end_form;
}

print $cgi->end_html;

sub add_age {
        my $age = $Session->param('age');
        ++$age;
        print $Session->param('name'), "\'s new age is $age";
        $Session->param(-name=>'age', -value=>$age);
        $Session->save_param($cgi);
        print $cgi->start_form,
                $cgi->hidden(-name=>'test', -value=>'test'),
                $cgi->submit('Next'),
                $cgi->end_form;
}
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