README

WP_DICH offers a way to work with WordPress hooks smartly using a Dependency Injection Container, allowing lazy loading, making classes to be loaded only when required.

The Challenge

Let's suppose you simply want to call a method method_a() from a class Any_Class only when a specific WordPress hook is run. How would you do it? There are at least 3 ways that come to my mind:

1. 👎 Object Method Call

The problem here is you are initializing Any_Class() before it's necessary, as you only need the method on wp_footer hook.

class Any_Class{
	public function method_a(){}
}
$any_class = new Any_Class();
add_action( 'wp_footer', array( $any_class, 'method_a') );

1. 👎 Using Anonymous Functions

The disadvantage here is you're not able to remove the action with remove_action()

class Any_Class{
	public function method_a(){}
}
add_action( 'wp_footer', function(){
	$any_class = new Any_Class();
	$any_class->method_a();
});

1. 👎 Using Static Methods

With the Static Methods approach, at least your class is loaded at the proper time, but quite often, from a design standpoint, it's better to stick to non-static methods. You can't override them, they are more difficult to test and you end up having to design other things around it as static too.

class Any_Class{
	public static function method_a(){}
}
add_action( 'wp_footer', array('Any_Class', 'method_a') );

👌 The WP_DICH Solution

WP_DICH combines the advantage of the Object Method Call, using a non static method, with the benefits of loading the class only when it's required. Check how it's simple:

First you need to pass a Dependency Injection Container Interface to WP_DICH().

$dic  = new \Thanks_To_IT\WP_DICH\DIC();
$dich = new \Thanks_To_IT\WP_DICH\WP_DICH( $dic );

WP_DICH already offers a small Dependency Injection Container, thanks to Carl Alexander, but you can use any library you want, like thephpleague/container or php-di for example. You just have to implement a Psr\Container\ContainerInterface with 2 methods, get() and has()

Then you just have to setup your container as you like:

$dic['any_class_alias'] = function () {
	return new Any_Class();
};

Now if you create your hook using the class alias you've configured on the container as the first parameter of the array, instead of calling a static method, it will load your class only when wp_footer hook is run and then method_a will be called.

$dich->add_action( 'wp_footer', array( 'any_class_alias', 'method_a') );

WP_DICH hooks

You can use the WordPress hook functions you are used to, like:

• $dich->add_action
• $dich->add_filter
• $dich->remove_action
• $dich->remove_filter

Services

As we are using a Dependency Injection Container Library we may benefit from some interesting features, like services, allowing to instantiate your classes only once. Yes, no need to think about Singletons anymore.

$dic['any_class_alias'] = $dic->service( function () {
	return new Any_Class();
} );

Now everytime you call for 'any_class_alias' the same object will be returned instead of creating a new one every time.

Installation

Composer Add thanks-to-it/wp-dich to the require-dev or require section of your project's composer.json configuration file, and run 'composer install':

{
    "require": {
        "thanks-to-it/wp-dich":"dev-master"
    }
}