get an php fatal error in codeigniter controller - php

Question

Here it is my code:
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class Login extends CI_Controller
{
public function __construct()
{
parent::__construct();
$this->load->database(); /* This function it's used to connect to database */
$this->load->model('User','user'); /* This call the model to retrieve data from db */
}
public function index()
{
if(!file_exists('application/views/_login.php'))
{
show_404();
}
$this->load->library('form_validation');
$this->form_validation->set_error_delimiters('<h4 style="text-align:center;">','</h4>');
$this->form_validation->set_rules('username','username','trim|required|xss_clean');
$this->form_validation->set_rules('password','password','trim|required|xss_clean|callback_pass_check');
if($this->form_validation->run() == FALSE)
{
$data['title'] = "User Access";
$data['author'] = "Salvatore Mazzarino";
$this->load->view('templates/_header',$data);
$this->load->view('_login',$data);
$this->load->view('templates/_footer',$data);
}
else
{
redirect('home', 'refresh');
}
}
public function pass_check($pass)
{
$result = $this->user->find_user($this->input->post('username'),$pass);
if($result == 1)
{
$session_array = array();
foreach ($result as $row)
{
$session_array = array('id'=> $row->id,'username'=> $row->username); /* Create a session passing user data */
$this->session->set_userdata('logged_in',$session_array);
}
return TRUE;
}
else
{
$this->form_validation->set_message('pass_check',"Invalid username or password!</br>Try again, please!");
return FALSE;
}
}
}
Here it is the line
$this->session->set_userdata('logged_in',$session_array);
that cause the error:
PHP Fatal error: Call to a member function set_userdata() on a non-object
Someone could say me the reason?

Answer 1

Make sure the session library is loaded.
You can add it in application/config/autoload.php to be loaded automatically.
http://ellislab.com/codeigniter/user_guide/libraries/sessions.html