CodeIgniter 3 PSR-4 Autoloader for Application

2.0.0 2019-07-13 17:24 UTC

This package is auto-updated.

Last update: 2023-03-06 14:28:02 UTC



CodeIgniter PSR-4 Autoload

CodeIgniter 3 PSR-4 Autoloader for Application

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This PSR-4 extension is collected into yidas/codeigniter-pack which is a complete solution for Codeigniter framework.


  • PSR-4 Namespace support as Yii2 & Laravel elegant patterns like

  • Easy way to use Interface, Trait, Abstract and Extending Class

  • Whole Codeigniter application directory structure support



By default, all PSR-4 namespace with app prefix in Codeigniter would relates to application directory.

  • The class /application/libraries/MemberService.php could be called by:
new \app\libraries\MemberService;
  • The class /application/services/Process.php with static run() method could be called by:
  • Enable to extend or implement classes with standard way:
class Blog_model extends app\models\BaseModel {}
class Blog extends app\components\BaseController {}
class Car implements app\contracts\CarInterface {}


This library requires the following:

  • PHP 5.3.0+
  • CodeIgniter 3.0.0+


Run Composer in your Codeigniter project under the folder \application:

composer require yidas/codeigniter-psr4-autoload

Check Codeigniter application/config/config.php:

$config['composer_autoload'] = TRUE;

You could customize the vendor path into $config['composer_autoload']


After installation, the namespace prefix app is used for the current Codeigniter application directory.

Static Class

Create a hepler with PSR-4 namespace with a new helpers folder under application directory, for eaxmple \application\helpers\:

namespace app\helpers;

class ArrayHelper
    public static function indexBy($input) {}

Then call it in Controller action:

use app\helpers\ArrayHelper;

Extending Class

Create a class with PSR-4 namespace under application directory, for eaxmple application/model/BaseModel.php:

namespace app\models;

class BaseModel extends \CI_Model {}

Then define a class to extend above class, for eaxmple application/model/My_model.php:


class My_model extends app\models\BaseModel {}

In this case, Codeigniter My_model could not use PSR-4 namespace.


Create a interface with a new interface folder under application directory, for eaxmple application/interface/CarInterface.php:

namespace app\interfaces;

interface CarInterface {}

Then apply the interface to a class, for eaxmple application/libraries/Car.php:

namespace app\libraries;

class Car implements \app\interfaces\CarInterface {}

In this case, the Car lib could be called by using new \app\libraries\Car;.


Create a trait under application directory, for eaxmple application/libraries/LogTrait.php:

namespace app\components;

trait LogTrait {}

Then inject the trait into a class, for eaxmple application/controller/Blog.php:

class Blog extends CI_Controller
    use \app\components\LogTrait;


Create an abstract under application directory, for eaxmple application/libraries/BaseController.php:

namespace app\components;

abstract class BaseController extends \CI_Controller {}

Then define a class to extend above abstract class, for eaxmple application/libraries/BaseController.php:

class Blog extends app\components\BaseController {}


Codeigniter Loader is a good practice for loading one time instantiated component just like Yii2 Application Components, but it's lacking of Class mapping, which makes inconvenience to load classes including interfaces, traits, abstracts or extending classes.

Thus, You could defind classes with PSR-4 Namespace while these classes are not component kind, even Helpers which you may want use static method and customized class name.


Namespace Class No Longer Support CI_Loader

The called class need to define namespace to support PSR-4 Autoload only, which means it would not support Built-in CI_Loader anymore.