Redirect to previous page, previous URL.

[eluser]8Lou[/eluser]
Hello folks,

I trying to redirect to previous page with codeigniter 2 and wont work with my code, any help plz?

Code:

function __construct() // se nao estiver logado, user sera redirecionado para pagina de login
{
session_start();
       parent::__construct();

                 if ( !isset($_SESSION['username']) ) {
            redirect('login');
   }


  if (isset($_SERVER['HTTP_REFERER']))
  {
  $this->session->set_userdata('previous_page', $_SERVER['HTTP_REFERER']);
  }
  else
  {
  $this->session->set_userdata('previous_page', base_url());
  }
}

Code:

function dosomething()
{
  $this->album_model->dellActPhotos();
  redirect($this->session->userdata('previous_page'));
}

when i use function 'dosomething' codeigniter redirect to base_url, whats wrong here?