Autoloading

Autoloading is a concept in PHP where you specific a directory or directories to load classes from. This is much more beneficial than using require or include to load classes. It is also a requirement for using Composer packages.

By default any Flight class is autoloaded for your automatically thanks to composer. However, if you want to autoload your own classes, you can use the Flight::path() method to specify a directory to load classes from.

Using an autoloader can help simplify your code in a significant way. Instead of having files start with a myriad of include or require statements at the top to capture all classes that are used in that file, you can instead dynamically call your classes and they will be included automatically.

Let's assume we have a directory tree like the following:

# Example path
/home/user/project/my-flight-project/
├── app
│   ├── cache
│   ├── config
│   ├── controllers - contains the controllers for this project
│   ├── translations
│   ├── UTILS - contains classes for just this application (this is all caps on purpose for an example later)
│   └── views
└── public
    └── css
    └── js
    └── index.php

You may have noticed that this is the same file structure as this documentation site.

You can specify each directory to load from like this:

/**
 * public/index.php
 */

// Add a path to the autoloader
Flight::path(__DIR__.'/../app/controllers/');
Flight::path(__DIR__.'/../app/utils/');

/**
 * app/controllers/MyController.php
 */

// no namespacing required

// All autoloaded classes are recommended to be Pascal Case (each word capitalized, no spaces)
class MyController {

    public function index() {
        // do something
    }
}

If you do have namespaces, it actually becomes very easy to implement this. You should use the Flight::path() method to specify the root directory (not the document root or public/ folder) of your application.

/**
 * public/index.php
 */

// Add a path to the autoloader
Flight::path(__DIR__.'/../');

Now this is what your controller might look like. Look at the example below, but pay attention to the comments for important information.

/**
 * app/controllers/MyController.php
 */

// namespaces are required
// namespaces are the same as the directory structure
// namespaces must follow the same case as the directory structure
// namespaces and directories cannot have any underscores (unless Loader::setV2ClassLoading(false) is set)
namespace app\controllers;

// All autoloaded classes are recommended to be Pascal Case (each word capitalized, no spaces)
// As of 3.7.2, you can use Pascal_Snake_Case for your class names by running Loader::setV2ClassLoading(false);
class MyController {

    public function index() {
        // do something
    }
}

And if you wanted to autoload a class in your utils directory, you would do basically the same thing:

/**
 * app/UTILS/ArrayHelperUtil.php
 */

// namespace must match the directory structure and case (note the UTILS directory is all caps
//     like in the file tree above)
namespace app\UTILS;

class ArrayHelperUtil {

    public function changeArrayCase(array $array) {
        // do something
    }
}

As of 3.7.2, you can use Pascal_Snake_Case for your class names by running Loader::setV2ClassLoading(false);. This will allow you to use underscores in your class names. This is not recommended, but it is available for those who need it.

use flight\core\Loader;

/**
 * public/index.php
 */

// Add a path to the autoloader
Flight::path(__DIR__.'/../app/controllers/');
Flight::path(__DIR__.'/../app/utils/');
Loader::setV2ClassLoading(false);

/**
 * app/controllers/My_Controller.php
 */

// no namespacing required

class My_Controller {

    public function index() {
        // do something
    }
}

• Routing - How to map routes to controllers and render views.
• Why a Framework? - Understanding the benefits of using a framework like Flight.

• If you can't seem to figure out why your namespaced classes aren't being found, remember to use Flight::path() to the root directory in your project, not your app/ or src/ directory or equivalent.

Class Not Found (autoloading not working)

There could be a couple reasons for this one not happening. Below are some examples but make sure you also check out the autoloading section.

Incorrect File Name

The most common is that the class name doesn't match the file name.

If you have a class named MyClass then the file should be named MyClass.php. If you have a class named MyClass and the file is named myclass.php then the autoloader won't be able to find it.

Incorrect Namespace

If you are using namespaces, then the namespace should match the directory structure.

// ...code...

// if your MyController is in the app/controllers directory and it's namespaced
// this will not work.
Flight::route('/hello', 'MyController->hello');

// you'll need to pick one of these options
Flight::route('/hello', 'app\controllers\MyController->hello');
// or if you have a use statement up top

use app\controllers\MyController;

Flight::route('/hello', [ MyController::class, 'hello' ]);
// also can be written
Flight::route('/hello', MyController::class.'->hello');
// also...
Flight::route('/hello', [ 'app\controllers\MyController', 'hello' ]);

path() not defined

In the skeleton app, this is defined inside the config.php file, but in order for your classes to be found, you need to make sure that the path() method is defined (probably to the root of your directory) before you try to use it.

// Add a path to the autoloader
Flight::path(__DIR__.'/../');

• v3.7.2 - You can use Pascal_Snake_Case for your class names by running Loader::setV2ClassLoading(false);
• v2.0 - Autoload functionality added.