Dependency Injection / IoC

[tobeycodes]

The scaffold currently has a pattern of Modules and a way to initialize these modules. These are useful but they do not allow for dependency injection which makes it harder to write easily testable code.

I think we should replace this in favour of a container and dependency injection. There are several popular packages to do this or we could maintain our own

https://github.com/silexphp/Pimple
https://github.com/PHP-DI/PHP-DI

[darylldoyle]

Thanks, @tobeycodes. I've added this to the Internal Tools working group agenda to be discussed. If you have any additional context/information that you think would be useful for those reviewing this, I'd greatly appreciate it if you could add it.

[tobeycodes]

@darylldoyle I don't have too much context to add but I can perhaps help with an example of what I mean

class Bitly extends Module
  // CANT DO THIS WITH MODULES
  public function __construct(
    private BitlyAPI $bitlyAPI,
  ) {}

  public function add_hooks() {
    add_action('save_post' [$this, 'add_bitly_short_url_on_save']);
  }

  public function add_bitly_short_url_on_save(WP_Post $post) {
     // CANT DO THIS WITH MODULES
    $this->bitlyAPI

    // NEED TO DO THIS OR PUT THE API CODE IN THIS CLASS AND CODE IS TIGHTLY COUPLED
    $bitlyApi = new BitlyAPI();
  }
}

By not using depedency injection we are making our code less testable and tighly coupling our WP actions/filters with generic PHP code. It makes it harder to refactor and replace any code in the future