[WordPress] Organizing Subscribers, WordPress Types, and Views

00-acme-meta-box-subscriber.php

<?php

class AcmeMetaBoxSubscriber extends AbstractSubscriber
{
    public function __construct(string $hook)
    {
        parent::__construct($hook);
    }

    public function load()
    {
        (new AcmeMetaBox())->render();
    }
}

01-acme-meta-box.php

<?php

class AcmeMetaBox extends AbstractMetaBox
{
    public function render()
    {
        add_meta_box(
            'acme-data',
            'Acme Data',
            [$this, 'display'],
            $this->postType,
            'normal',
            'high'
        );
    }

    public function display()
    {
        include_once plugin_dir_path(__FILE__).'Views/acme-data.php';
    }
}

02-acme-data.php

<div class="acme-data-metabox">
  <?php echo __('Acme Data', 'acme-meta-box'); ?>
  <p class="description">
    This is the content of the metabox.
  </p>
</div>

03-plugin.php

<?php

class Plugin
{
    private $registry;
  
    public function __construct(Registry $registry)
    {
        $this->registry = $registry;
    }

    public function start()
    {
        array_map(function ($subscriber) {
            add_action($subscriber->getHook(), [$subscriber, 'load']);
        }, $this->registry->getRegisteredSubscribers());
    }
}

04-bootstrap.php

<?php

// Setup a filter so we can retrieve the registry throughout the plugin.
$registry = new Registry();
add_filter('acmeApiRegistry', function () use ($registry) {
    return $registry;
});

// Register all of our objects with a basic registry.
$registry->add('acmeMetaBoxSubscriber', new AcmeMetaBoxSubscriber('add_meta_boxes'));

$plugin = new Plugin($registry);
$plugin->start();