codeigniter session issue - some session info not sticking

Question

I'm using codeigniter session library to hold data that is used in a series of 3 pages and I'm experiencing strange behavior. My session variables remain in tact but the values disapear. Even stranger: I'm trying to store a serialized array in my session data and the first item of the array ends up being stored in a different variable?

I've attached a link that starts at the first page in the series where it is possible to click to the next page. I've printed the user_session data at the top of both pages (the third page isn't set up yet).

http://playmatics.com/nypl/site/index.php/member_area/quest/accept_quest/12

Sessions work everywhere else, for example I'm using a session to store login data and that works fine.

I've attached my controller and view below

    //CONTROLLER:
    function accept_quest() {
        $assoc_quest_id = end($this->uri->segments);

        if(!isset($quest_id)) {
            redirect('member_area/quest');
            //SEND A MESSAGE: NO QUEST STARTED
        }

        $quest_rows = $this->quest_model->get_quest_with_images($assoc_quest_id);
        $quest = current($quest_rows);
        $images = $this->pull_out_images($quest_rows);

        //the data array is used both in the session, 
        //to pass values over to the next function in the quest chain
        //and in the template
        $data = array();
        $data['quest_id'] = $assoc_quest_id;
        $data['instruction_text'] = $quest->instructions;
        $data['quest_title'] = $quest->name;
        $data['quest_time_limit'] = $quest->time_limit;
        $data['points_awarded'] =  $quest->points_availible;
        $data['quest_images'] = serialize($images);

       //save data in a flash session to be used in the next function call in the quest chain: quest_action
       $this->session->set_userdata($data);
       print_r($this->session->all_userdata());


       //the following data aren't needed in the session so they are added to the data array after the session has been set
       $data['annotation_text'] = $quest->note;        
       $data['main_content'] = 'quests/quest_desc';
       $this->load->view('includes/template', $data);
}


function quest_action() {
    print_r($this->session->all_userdata());

    $quest_id = $this->session->userdata('quest_id');
    echo "the quest id is: $quest_id";
    if(!isset($quest_id)) {
        redirect('member_area/quest');
        //SEND A MESSAGE: NO QUEST STARTED
    }

    $data['quest_id'] = $quest_id;
    $data['quest_title'] = $this->session->userdata('quest_title');
    $data['quest_images'] = $this->session->userdata('images');
    $data['instruction_text'] = $this->session->userdata('instructions');
    $data['quest_time_limit'] = $this->session->userdata('quest_time_limit');

    $data['main_content'] = 'quests/quest_action';
    $this->load->view('includes/template', $data);                
}

//VIEW
   //quest_desc:
<h1><?= $quest_title ?></h1>
    <div id="quest_elements">
        <figure>
        <? foreach(unserialize($quest_images) as $image): ?>
            <img class="media" src="<?= $image ?>" alt="<?= $quest_title ?> image"/>
        <? endforeach; ?>
            <figcaption>annotation: <?= $annotation_text ?></figcaption>
        </figure>
        <?= anchor("member_area/quest/quest_action", "Start Quest", array('title' => 'start quest')); ?>
    </div><!-- end quest_elements -->


    //quest_action:
<h1><?= $quest_title ?></h1>
    <div id="quest_elements">
        <figure>
        <? foreach(unserialize($quest_images) as $image): ?>
            <img class="media" src="<?= $image ?>" alt="<?= $quest_title ?> image"/>
        <? endforeach; ?>
            <figcaption>instructions: <?= $instruction_text ?></figcaption>
        </figure>
    <div id="timer">
        <?= $quest_time_limit; ?>
    </div>
    <?= anchor("#start_timer", "Start Timer", array('title' => 'start quest timer')); ?>
</div>

Answer 1

If you are hitting the cookie size limit, I would suggest switching to CodeIgniter's native Database Sessions class. This enables you to store session information in a database, effectively removing the cookie size limitation, you are simply restricted to the size of the user_data field in the ci_sessions database.

Following the link above, the section on utilizing database sessions is near the bottom, providing you the proper DB schema and the config switch to database sessions.

Answer 2

As others have said, it is likely that you are hitting the 4k cookie limit of CI's session library. There are other alternative libraries available that use standard PHP sessions - http://codeigniter.com/wiki/PHPSession/ and http://codeigniter.com/wiki/Native_session/ for instance.