AdvisoriesConfigSubscriber.php

<?php

namespace Drupal\system\EventSubscriber;

use Drupal\Core\Config\ConfigCrudEvent;
use Drupal\Core\Config\ConfigEvents;
use Drupal\system\SecurityAdvisories\SecurityAdvisoriesFetcher;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Defines a config subscriber for changes to 'system.advisories'.
 */
class AdvisoriesConfigSubscriber implements EventSubscriberInterface {
    
    /**
     * The security advisory fetcher service.
     *
     * @var \Drupal\system\SecurityAdvisories\SecurityAdvisoriesFetcher
     */
    protected $securityAdvisoriesFetcher;
    
    /**
     * Constructs a new ConfigSubscriber object.
     *
     * @param \Drupal\system\SecurityAdvisories\SecurityAdvisoriesFetcher $security_advisories_fetcher
     *   The security advisory fetcher service.
     */
    public function __construct(SecurityAdvisoriesFetcher $security_advisories_fetcher) {
        $this->securityAdvisoriesFetcher = $security_advisories_fetcher;
    }
    
    /**
     * Deletes the stored response from the security advisories feed, if needed.
     *
     * The stored response will only be deleted if the 'interval_hours' config
     * setting is reduced from the previous value.
     *
     * @param \Drupal\Core\Config\ConfigCrudEvent $event
     *   The configuration event.
     */
    public function onConfigSave(ConfigCrudEvent $event) : void {
        $saved_config = $event->getConfig();
        if ($saved_config->getName() === 'system.advisories' && $event->isChanged('interval_hours')) {
            $original_interval = $saved_config->getOriginal('interval_hours');
            if ($original_interval && $saved_config->get('interval_hours') < $original_interval) {
                // If the new interval is less than the original interval, delete the
                // stored results.
                $this->securityAdvisoriesFetcher
                    ->deleteStoredResponse();
            }
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() : array {
        $events[ConfigEvents::SAVE][] = [
            'onConfigSave',
        ];
        return $events;
    }

}