How to autoload codeigniter4 library once and access it every where in Controller, Model, View like in CI3

Question

In CI3 we make custom library and auto-load it in config/autoload.php then we able to use it everywhere in controller,model,view by simple $this->rules->status() where Rules is library in application/library folder

But unable to do the same thing in CI 4, is there any alternate available for this

Answer 1

If you want to load your own library you have to rely on namespaces and create a new object whenever you want to use this lib. Also be sure to check app/Config/Autoload.php file so your custom lib is known by the autoloader.
Since codeigniter 3 superobject has been removed you can't access it everywhere whenever you want. However you can load it into a view, a controller and a model and make your views, controllers and models extending it.

For example a lib named FooLib which is in app/Librairies will be :

namespace App\Libraries;  

  class FooLib {

    public function __construct() {
      // your constructor
    }

    // ...
    
   }

And if you want to call it in a Controller :

namespace App\Controllers;

use App\Libraries\FooLib;
use CodeIgniter\Controller;

class FooController extends Controller {

    protected $lib;

    public function __construct() {
        $this->lib = new FooLib();
    }
}

And make sure to add it to the autoloader in app/Config/Autoload.php by modifing$psr4 variable if your lib folder is outside of the app folder.

$psr4 = [
            'App'         => APPPATH,                // To ensure filters, etc still found,
            APP_NAMESPACE => APPPATH,                // For custom namespace
            'Config'      => APPPATH . 'Config',
            'Libraries'   => APPPATH . 'Libraries'   // Your custom librairies
        ];