DummyMimeTypeMapLoadedSubscriber.php

<?php

declare (strict_types=1);
namespace Drupal\file_test\EventSubscriber;

use Drupal\Core\File\Event\MimeTypeMapLoadedEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
// cspell:ignore garply tarz

/**
 * Modifies the MIME type map by adding dummy mappings.
 */
class DummyMimeTypeMapLoadedSubscriber implements EventSubscriberInterface {
    
    /**
     * {@inheritdoc}
     */
    public function onMimeTypeMapLoaded(MimeTypeMapLoadedEvent $event) : void {
        // Add new mappings.
        $event->map
            ->addMapping('made_up/file_test_1', 'file_test_1');
        $event->map
            ->addMapping('made_up/file_test_2', 'file_test_2');
        $event->map
            ->addMapping('made_up/file_test_2', 'file_test_3');
        $event->map
            ->addMapping('application/x-compress', 'z');
        $event->map
            ->addMapping('application/x-tarz', 'tar.z');
        $event->map
            ->addMapping('application/x-garply-waldo', 'garply.waldo');
        // Override existing mapping.
        $event->map
            ->addMapping('made_up/doc', 'doc');
    }
    
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() : array {
        return [
            MimeTypeMapLoadedEvent::class => 'onMimeTypeMapLoaded',
        ];
    }

}