progressive_image_loading-8.x-1.x-dev/src/Plugin/Filter/RevertProgressiveImageLoadingFilter.php

<?php

namespace Drupal\progressive_image_loading\Plugin\Filter;

use Drupal\Component\Utility\Html as HtmlUtility;
use Drupal\filter\FilterProcessResult;
use Drupal\filter\Plugin\FilterBase;

/**
 * Provides a filter to revert the progressive image loading changes.
 *
 * @Filter(
 *   id = "progressive_image_loading_revert",
 *   title = @Translation("Revert Progressive Image Loading changes"),
 *   type = Drupal\filter\Plugin\FilterInterface::TYPE_TRANSFORM_REVERSIBLE
 * )
 */
class RevertProgressiveImageLoadingFilter extends FilterBase {

  /**
   * {@inheritdoc}
   */
  public function process($text, $langcode) {
    $result = new FilterProcessResult($text);

    $dom = HtmlUtility::load($text);
    $xpath = new \DOMXPath($dom);

    $images = $xpath->query('//img');
    if ($images->length) {
      /** @var \DOMElement[] $images */
      foreach ($images as $image) {
        if ($image->hasAttribute('data-srcset')) {
          $image->setAttribute('srcset', $image->getAttribute('data-srcset'));
          $image->removeAttribute('data-srcset');
        }
        elseif ($image->hasAttribute('data-src')) {
          $image->setAttribute('src', $image->getAttribute('data-src'));
          $image->removeAttribute('data-src');
        }
      }
    }

    $backgrounds = $xpath->query('//*[@data-background-image]');
    if ($backgrounds->length) {
      /** @var \DOMElement[] $backgrounds */
      foreach ($backgrounds as $background) {
        $url = $background->getAttribute('data-background-image');
        $style = 'background-image: url("' . $url . '")' . $background->getAttribute('style');
        $background->setAttribute('style', $style);

        foreach ($background->attributes as $name => $attribute) {
          if (strpos($name, 'data-background-image') !== FALSE) {
            $background->removeAttribute($name);
          }
        }
      }
    }

    $iframes = $xpath->query('//iframe');
    if ($iframes->length) {
      /** @var \DOMElement[] $iframes */
      foreach ($iframes as $iframe) {
        if ($iframe->hasAttribute('data-src')) {
          $iframe->setAttribute('src', $image->getAttribute('data-src'));
          $iframe->removeAttribute('data-src');
        }
      }
    }

    if ($images->length || $backgrounds->length || $iframes->length) {
      $result->setProcessedText(HtmlUtility::serialize($dom));
    }

    return $result;
  }

}