Class not found for elFinder(Open-source file manager for web) in Codeigniter 4

1. You can remove the include_once lines in your elfinder_lib class.
2. Elfinder is not using PSR4 to name their classes so you cannot do so either. You should use class map.
app/Config/Autoload.php

PHP Code:

public $classmap = [
    'elFinderConnector' => APPPATH . 'ThirdParty/elfinder/elFinderConnector.class.php',
    // enumerate other elfinder classes
]; 


3. In your elfinder_lib class, when calling elFinderConnector you should qualify the call.

PHP Code:

<?php
namespace App\Libraries;

class Elfinder_lib 
{
  public function run($opts) {
        $connector = new \elFinderConnector(new \elFinder($opts));
        return $connector->run();
    }
} 


4. Alternative to #3, you can import them instead

PHP Code:

<?php
namespace App\Libraries;

use elFinderConnector;
use elFinder;

class Elfinder_lib 
{
  public function run($opts) {
        $connector = new elFinderConnector(new elFinder($opts));
        return $connector->run();
    }
}