Changing content when user has logged in i.e. when session starts - php

Question

How do I change the content for a user when he logs in? I mean like enabling voting, changing "login" to "logout" etc.
What I think to do is to start the session when user logs in (I am preferring to start session only when user logs in, not all the time). Then add data to the session's cookie like-
//controller
$moredata = array(
'username' => $this->username,
'login' => TRUE
);
$this->session->set_userdata($modedata);
//redirect
Then in the other controller, where he has been redirected I check the following-
$login = $this->session->userdata('login');
if ($login==TRUE)
Depending on the 'if' condition I will pass a variable to the view, with the help of that variable I will forward only the div/sections which should be shown to a logged-in user.
The problem is, while performing the above comparison Codeigniter shows following error (remember I haven't added 'session' in autoload array yet)
Message: Undefined property: NameOfController::$session
And If I set following in the autoload file
$autoload['libraries'] = array('session');
then the "if ($login==TRUE)" comparison always shows FALSE.
What should I do?

Answer 1

If I were you, I'd place all your session checks in a base controller which all your other main controllers extend. This allows you to keep things DRY:
class BaseController extends CI_Controller {
public function __construct()
{
parent::__construct();
}
public function isLoggedIn()
{
// Will return true or false
return $this->session->userdata('login');
}
}
And in one of your functional controllers (the example below handles users):
class UserController extends BaseController {
public function __construct()
{
parent::__construct();
}
public function profile()
{
// Redirect if not logged in
if (!$this->isLoggedIn()) {
$this->redirect('some/other/page')
}
}
public function register()
{
// Show different HTML if not logged in
$data = array(
'isLoggedIn' => $this->isLoggedIn()
);
$this->load->view('register', $data);
}
}
The second method in UserController allows you to render different content in your view:
<? if ($isLoggedIn): ?>
<p>You're logged in!</p>
<? else: ?>
<p>Not logged in</p>
<? endif; ?>

Answer 2

On my last project we created a simple permissions helper that had functions to check for logged-in status and for privilege levels. Then we'd just call the helper's functions as needed from anywhere in the system. If the user is logged in and has privs for that content then they get the content - otherwise we'd redirect them to a registration or other error page. Since all of that logic is in the helper functions, we could wrap any permission-requiring code in a quick permissions call like if(is_logged_in()){code requiring login to access}.