Use session data in Hook in CodeIgniter 2.1.0

Question

I am using CodeIgniter with version 2.1.0. I want to use Hooks for login authentication. That means I want in every controller check the session data if loggedin or not. So I want to use hooks. I do the following code for doing that:

In config file

$config['enable_hooks'] = TRUE;

In file hooks.php

$hook['post_controller_constructor'][] = array(
                               'class'    => 'SessionData',
                               'function' => 'initializeData',
                               'filename' => 'loginHelper.php',
                               'filepath' => 'hooks',
                               'params'   => array()
                               );

In file loginHelper.php

class SessionData{
    var $CI;

    function __construct(){
        $this->CI =& get_instance();
    }

    function initializeData() {

        // This function will run after the constructor for the controller is ran
        // Set any initial values here
        if (!$this->session->userdata('username')) { // This is line 13
            redirect('login');
        }
    }
}

But it throws the following error:

A PHP Error was encountered

Severity: Notice

Message: Undefined property: SessionData::$session

Filename: hooks/loginHelper.php

Line Number: 13

How can I solve this?

Answer 1

"Called very early during system execution. Only the benchmark and hooks class have been loaded at this point..."

You should load all libraries and models manually that you use inside Hook:

if (!isset($this->CI->session))
{
    $this->CI->load->library('session');
}

And use $this->CI->session->userdata() instead of $this->session->userdata().