auth.php

<?php namespace App\Filters;

use CodeIgniter\HTTP\RequestInterface;
use CodeIgniter\HTTP\ResponseInterface;
use CodeIgniter\Filters\FilterInterface;

class Auth implements FilterInterface
{
    public function before(RequestInterface $request, $arguments = null)
    {
        // Do something here
        if(!session()->has('isLoggedIn'))
        {
        	return redirect()->to(site_url('auth/login'));
        }
    }

    //--------------------------------------------------------------------

    public function after(RequestInterface $request, ResponseInterface $response, $arguments = null)
    {
        // Do something here
    }
 }