set_header in MY_Controller codeigniter 3 not working - codeigniter

Question

I have extending ci_controller like this on application/core
class MY_Controller extends CI_Controller {
public function __construct() {
parent::__construct();
$this->output->set_header("Cache-Control: no-store, no-cache, must-revalidate, no-transform, max-age=0, post-check=0, pre-check=0");
$this->output->set_header("Pragma: no-cache");
}
}
class Public_Controller extends MY_Controller {
public $layout = 'layout';
}
class Surveyor_Controller extends MY_Controller {
public $layout = 'surveyor/template/layout';
public function __construct() {
parent::__construct();
$login_status = $this->session->userdata('login_status');
$group = $this->session->userdata('group');
if (($login_status !== true) && ($group !== 3)) {
redirect(base_url());
}
// Pastikan hanya "operator" yang boleh mengakses.
if ($group !== '3') {
$this->session->set_flashdata('error', 'Anda tidak berhak mengakses halaman ini!');
redirect(base_url());
}
}
}
My question is, back arrow page is still working
So, in application/controller : i made a new class like this :
class C_surveyor extends Surveyor_Controller {
public $data = array(
'halaman' => 'home',
'main_view' => 'surveyor/v_home'
);
public function __construct() {
parent::__construct();
$this->load->helper('form');
$this->load->model('m_surveyor');
}
public function index() {
$this->load->view($this->layout, $this->data);
}
Just say user has on index, and clik arrow back so get login page. Header not working. When user click right arraow, it still get index page.
Where am I missing ?
Any solution it so appreciated

Answer 1

Try adding this code instead of that 2 lines,
$this->output->set_header("HTTP/1.0 200 OK");
$this->output->set_header("HTTP/1.1 200 OK");
$this->output->set_header('Last-Modified: '.gmdate('D, d M Y H:i:s', $last_update).' GMT');
$this->output->set_header("Cache-Control: no-store, no-cache, must-revalidate");
$this->output->set_header("Cache-Control: post-check=0, pre-check=0");
$this->output->set_header("Pragma: no-cache");
Refer This