private controller example

//application/core/PrivateController
<?php

class PrivateController extends BaseController {

    public $userSessionData = null;

    public function __construct() {
        parent::__construct();
        if (!$this->authorization->isLoggedIn()) {
            redirect('auth');
        }
        $this->load->library(['Breadcrumbs', 'form_validation', 'pagination']);
        $this->lang->init('cookies');
        $this->breadcrumbs->push('Dashboard', 'admin/dashboard');
        $this->template
                ->setTheme('backend')
                ->setTpl('base_tpl')
                ->addAssets([
                    'customCss' => ['vendor/bootstrap/css/bootstrap.min.css', 'vendor/metisMenu/metisMenu.min.css', 'vendor/font-awesome/css/font-awesome.min.css'],
                    'customJs' => ['vendor/jquery/jquery-2.1.1.min.js', 'vendor/bootstrap/js/bootstrap.min.js', 'vendor/metisMenu/metisMenu.min.js'],
                    'css' => ['sb-admin-2.min.css', 'style.css'],
                    'js' => ['sb-admin-2.js', 'script.js']
                ])
                ->setData([
                    'pageTitle' => 'Admin Panel'
                ])
                ->setBlocks([
                    'main' => $this->router->class . DIRECTORY_SEPARATOR . $this->router->method,
                    'header' => 'header',
                    'footer' => 'footer',
                    'top' => 'top',
                    'navigation' => 'navigation'
        ]);
    }

}

//application/controllers/admin/Php_logs

<?php

defined('BASEPATH') OR exit('No direct script access allowed');

class Php_logs extends PrivateController {

    public function __construct() {
    parent::__construct();
    $this->breadcrumbs->push('PHP logs', 'admin/php_logs');
    $this->template->setBlocks(['sub_nav' => 'php_logs/_sub_nav']);
    $this->load->model('PHPLogsModel');
    }

    public function index() {
    $data['logList'] = $this->PHPLogsModel->parseDirectory();
    $data['currentFile'] = $data['logList'] ? current($data['logList']) : null;
    if ($data['logList']) {
        $data['currentFile'] = current($data['logList']);
    }
    if ($this->uri->rsegment(3)) {
        $data['currentFile'] = $this->uri->rsegment(3);
    }
    if (!is_null($data['currentFile']) && !in_array($data['currentFile'], $data['logList'], true)) {
        show_404();
    }
    $data['logs'] = $this->PHPLogsModel->parseFile($data['currentFile']);
    $this->template->addAssets(['js' => ['php-logs.js']])->render($data);
    }

    public function delete() {
    $file = $this->uri->rsegment(3);
    if($file){
        $this->PHPLogsModel->deleteFile($file);
        $this->flashmessages->set("PHP logs file {$file} deleted", 'danger');
    }
    redirect('admin/php_logs');
    }

}