postoffice-1.0.x-dev/extensions/postoffice_image/src/EventSubscriber/ImageAdjustmentSubscriber.php

<?php

namespace Drupal\postoffice_image\EventSubscriber;

use Drupal\Component\Utility\Html;
use Drupal\file\Entity\File;
use Drupal\image\Entity\ImageStyle;
use Drupal\image\ImageStyleInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\RequestStack;
use Symfony\Component\Mailer\Event\MessageEvent;
use Symfony\Component\Mime\Email;

/**
 * Applies image adjustments defined by field formatter third party settings.
 *
 * Runs with priority -50 (after Symfony MessageListener which is responsible
 * for body rendering).
 */
class ImageAdjustmentSubscriber implements EventSubscriberInterface {

  /**
   * Constructs new message subscriber for email image adjustments.
   */
  public function __construct(protected RequestStack $requestStack) {
  }

  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents(): array {
    $events = [];
    $events[MessageEvent::class] = ['onMessage', -50];
    return $events;
  }

  /**
   * Embeds images supplied by image field formatter.
   */
  public function onMessage(MessageEvent $event): void {
    $message = $event->getMessage();
    if (
      $message instanceof Email &&
      $message->getHtmlBody() && (
        strpos($message->getHtmlBody(), 'data-postoffice-image-embed-target-id') !== FALSE ||
        strpos($message->getHtmlBody(), 'data-postoffice-image-transform-urls') !== FALSE
      )
    ) {
      $dom = Html::load($message->getHtmlBody());
      $xpath = new \DOMXpath($dom);
      foreach ($xpath->query("//img[@data-postoffice-image-embed-target-id]") as $node) {
        $fileId = $node->getAttribute('data-postoffice-image-embed-target-id');
        $style = $node->getAttribute('data-postoffice-image-embed-style-name');

        $file = File::load($fileId);
        if ($file) {
          $uri = $file->getFileUri();
          if (!empty($style)) {
            $styleEntity = ImageStyle::load($style);
            $uri = $styleEntity ? $this->generateStyle($uri, $styleEntity) : NULL;
          }
          if (!empty($uri)) {
            $cid = \urlencode(\basename($uri));
            $message->embedFromPath($uri, $cid);
            $node->setAttribute('src', 'cid:' . $cid);
          }
        }
      }
      foreach ($xpath->query("//img[@data-postoffice-image-transform-urls and starts-with(@src, '/') and not(starts-with(@src, '//'))]") as $node) {
        $url = $this->getSchemeAndHttpHost() . $node->getAttribute('src');
        $node->setAttribute('src', $url);
      }
      $message->html(Html::serialize($dom));
    }
  }

  /**
   * Generates derivative and return URI for given image / style.
   */
  protected function generateStyle($imageUri, ImageStyleInterface $style): ?string {
    $derivativeUri = $style->buildUri($imageUri);

    if (!file_exists($derivativeUri)) {
      $style->createDerivative($imageUri, $derivativeUri);
    }

    return file_exists($derivativeUri) ? $derivativeUri : NULL;
  }

  /**
   * Returns scheme and HTTP host.
   */
  protected function getSchemeAndHttpHost(): string {
    $request = $this->requestStack->getCurrentRequest();
    return $request->getSchemeAndHttpHost();
  }

}