Introduction

Air is the dependency injection factory for litphp

Installation

composer require litphp/air

Concept of DI and air

You may read this page from PHP-DI for basic concept of dependency injection.

The two main class of air is Factory and Container, former is the DI factory, and the latter is container serving for DI factory. We devide them to two separate class, so Container can focus on container logic itself, a.k.a. highly customizable key-value storage, while Factory focus on the complex and tricky part in DI: autowiring.

Dynamic entries in Container need to implement RecipeInterface (and called Recipe), and recipe can be decorated by RecipeDocarators. This is also how Container call Factory to create DI products: built-in recipes like AutowireRecipe or InstanceRecipe calling Factory to produce.

A little taste

$container = new Container();
$container->set('foo', 'bar'); // write entry directly
assert($container->get('foo') === 'bar');

$container->define('baz', new AliasRecipe('foo')); 
// or ->define('baz', Container::alias('foo'))

assert($container->get('foo') === 'bar'); // use alias recipe to create alias for entry

class A {}
class B {
  public $a;
  public function __construct(A $a) {
    $this->a = $a;
  }
}

$b = Factory::of($container)->produce(B::class);
assert($b instanceof B);
assert($b->a instanceof A);