Symfony Twig Templating Engine with Codeigniter 3

My_Controller.php

<?php

use Twig\Environment;
use Twig\Loader\FilesystemLoader;
use Twig\TwigFunction;


/**
* Create My_controller.php file in the application/core folder
* please change the subclass_prefix in application/config/config.php from MY to My
* or if you want as it is please name this file and class with MY_Controller.
*
*
*/
class My_Controller extends CI_Controller {

    protected $loader;
    protected $twig;
    protected $view_path = APPPATH . "views";
    protected $cache_path = APPPATH . "cache";
    protected $CI;

    public function __construct() {
        parent::__construct();
        $this->loader = new FilesystemLoader( $this->view_path );
        $this->twig = new Environment( $this->loader, [
            'template_ext' => 'twig',
            'debug' => true
        ] );
        $this->registerFunctions();
        $this->CI = &get_instance();
    }

    /**
     * render the template
     *
     * @param string $file
     * @param array $data
     * @return void
     */
    public function render( $file, $data = [] ) {
        if ( empty( $data ) ) {
            echo $this->twig->render( $file );
        } else {
            echo $this->twig->render( $file, $data );
        }
    }

    /**
     * get all the loaded files
     *
     * @return array
     */
    public function getLoadedHelperFiles() {
        $ci_helpers = array_filter( array_map( function ( $file ) {
            return stripos( $file, "_helper.php" ) !== false ?
            basename( $file, ".php" ) : false;
        }, get_included_files() ) );
        return $ci_helpers;
    }

    /**
     * get the all the helper functions from the loaded files
     *
     * @return array
     */
    public function getHelpers() {
        $core_helpers_path = FCPATH . "system/helpers/";
        $helpers = APPPATH . "helpers/";
        $files = $this->getLoadedHelperFiles();
        $helper_functions = [];
        foreach ( $files as $file ) {
            $system_file = $core_helpers_path . $file . ".php";
            $user_file = $helpers . $file . ".php";
            if ( file_exists( $system_file ) ) {
                $functions = $this->functions_in_file( $system_file );
                $helper_functions = array_merge( $helper_functions, $functions );
            }
            if ( file_exists( $user_file ) ) {
                $functions = $this->functions_in_file( $user_file );
                $helper_functions = array_merge( $helper_functions, $functions );
            }
        }
        return $helper_functions;
    }

    /**
     * gather functions from the php file
     *
     * @param string $file
     * @param boolean $sort
     * @return array
     */
    public function functions_in_file( $file, $sort = FALSE ) {
        $file = join( "\n", file( $file ) );
        preg_match_all( '/function\s+(\w+)/', $file, $m );
        $functions = $m[1];
        if ( $sort ) {
            asort( $functions );
        }
        return $functions;
    }

    /**
     * Register helpers functions to the twig
     *
     * @return void
     */
    public function registerFunctions() {
        foreach ( $this->getHelpers() as $helper ) {
            try {
                $this->twig->addFunction( new TwigFunction( $helper, $helper ) );
            } catch ( \Exception$e ) {
                continue;
            }
        }
    }

    /**
     * @param array $array
     * @return mixed
     */
    public function JSONResponse(array $array)
    {
        return $this->output
                    ->set_content_type('application/json')
                    ->set_output(json_encode($array));
    }


    public function ajax()
    {
        return 'XMLHttpRequest' === $this->input->get_request_header('X-Requested-With');
    }

}

Welcome.php

<?php


/**
* In your controller extends you controller class with My_controller or MY_Controller
* in the application/views directory rename welcome_message.php to welcome_message.twig 
*
*/
class Welcome extends My_Controller{

  
  public function index(){
    $this->render("welcome_message", [
      "message" => "Welcome to Codeigniter 3 with Twig <3"
    ]);
  }
  
  

}

welcome_message.twig

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Welcome</title>
</head>
<body>
  <h1>{{ message }}</h1>
</body>
</html>