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

<?php

namespace Drupal\progressive_image_loading\Plugin\Filter;

use Drupal\Component\Utility\Html as HtmlUtility;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\filter\FilterProcessResult;
use Drupal\filter\Plugin\FilterBase;
use Drupal\progressive_image_loading\ProgressiveImageLoadingManagerInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Provides a filter to attach the libraries for this module.
 *
 * @Filter(
 *   id = "progressive_image_loading",
 *   title = @Translation("Progressive Image Loading"),
 *   description = @Translation("Loads progressively all the images and iframes."),
 *   type = Drupal\filter\Plugin\FilterInterface::TYPE_TRANSFORM_REVERSIBLE
 * )
 */
class ProgressiveImageLoadingFilter extends FilterBase implements ContainerFactoryPluginInterface {

  /**
   * The Progressive Image Loading manager.
   *
   * @var \Drupal\progressive_image_loading\ProgressiveImageLoadingManagerInterface
   */
  protected $manager;

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    $instance = new static($configuration, $plugin_id, $plugin_definition);

    $instance->setManager($container->get('progressive_image_loading.manager'));
    return $instance;
  }

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

    if (!$this->manager->currentPathIsExcluded()) {
      $dom = HtmlUtility::load($text);
      $xpath = new \DOMXPath($dom);

      $enabled = $xpath->query('//*[contains(@class, "progressive-image-loading")]')->length +
        $xpath->query('//*[@data-toggle-class]')->length;

      $images = $xpath->query('//img');
      if ($images->length) {
        /** @var \DOMElement[] $images */
        foreach ($images as $image) {
          $classes = $image->getAttribute('class');
          if (strpos($classes, 'progressive-image-loading-disabled') === FALSE) {
            $image->setAttribute('class', trim('progressive-image-loading ' . $classes));

            if ($image->hasAttribute('srcset')) {
              $image->setAttribute('data-srcset', $image->getAttribute('srcset'));
              $image->removeAttribute('srcset');
            }

            // Generate a LQIP image.
            $url = $image->getAttribute('src');
            $width = $image->getAttribute('width') ?? 1;
            $height = $image->getAttribute('height') ?? 1;
            $placeholder = $this->manager->createPlaceholder($url, $width, $height);

            // Only use this attribute if the placeholder is different.
            if ($url != $placeholder) {
              $image->setAttribute('data-src', $url);
            }
            $image->setAttribute('src', $placeholder);
            $enabled++;
          }
        }
      }

      $backgrounds = $xpath->query('//*[@data-background-image]');
      if ($backgrounds->length) {
        /** @var \DOMElement[] $backgrounds */
        foreach ($backgrounds as $background) {
          $classes = $background->getAttribute('class');
          if (strpos($classes, 'progressive-image-loading-disabled') === FALSE) {
            $background->setAttribute('class', trim('progressive-image-loading ' . $classes));

            // Generate a LQIP image.
            $url = $background->getAttribute('data-background-image');
            $placeholder = $this->manager->createPlaceholder($url);

            // Only use this attribute if the placeholder is different.
            if ($url != $placeholder) {
              $style = 'background-image: url("' . $placeholder . '")' . $background->getAttribute('style');
              $background->setAttribute('style', $style);
            }
            $enabled++;
          }
        }
      }

      $iframes = $xpath->query('//iframe');
      if ($iframes->length) {
        /** @var \DOMElement[] $iframes */
        foreach ($iframes as $iframe) {
          $classes = $iframe->getAttribute('class');
          if (strpos($classes, 'progressive-image-loading-disabled') === FALSE) {
            $iframe->setAttribute('class', trim('progressive-image-loading ' . $classes));
            $iframe->setAttribute('data-src', $iframe->getAttribute('src'));
            $iframe->removeAttribute('src');
            $enabled++;
          }
        }
      }

      if ($images->length || $backgrounds->length || $iframes->length) {
        $result->setProcessedText(HtmlUtility::serialize($dom));
      }
      if ($enabled) {
        $result->addAttachments([
          'library' => [
            'progressive_image_loading/library',
          ],
        ]);
      }
    }

    return $result;
  }

  /**
   * {@inheritdoc}
   */
  public function tips($long = FALSE) {
    return $this->t('
      <p>You can disable progressive image loading adding (<code>class="progressive-image-loading-disabled"</code>) to yours images or iframes.</p>
      <p>You can disable progressive image loading blur effect adding (<code>class="progressive-image-loading-disable-blur"</code>) to yours images or iframes.</p>
      <p>You can add progressive background image loading. Example: <code>&lt;div data-background-image=""&gt;&nbsp;&lt;/div&gt;</code></p>
    ');
  }

  /**
   * Sets the Progressive Image Loading manager for this filter.
   *
   * @param \Drupal\progressive_image_loading\ProgressiveImageLoadingManagerInterface $manager
   *   The Progressive Image Loading manager.
   *
   * @return $this
   */
  protected function setManager(ProgressiveImageLoadingManagerInterface $manager) {
    $this->manager = $manager;

    return $this;
  }

}