FilterUrlNormalizer

FilterUrlNormalizer.php

<?php

class FilterUrlNormalizer extends FilterBase {

  /**
   * {@inheritdoc}
   */
  public function process($text, $langcode) {
    $dom = Html::load($text);
    $metadata = new CacheableMetadata();
    /** @var \DOMElement $element */
    foreach ($dom->getElementsByTagName('a') as $element) {
      $link = $element->getAttribute('href');
      if (!$link || $link[0] === '#') {
        continue;
      }
      if (($url = \Drupal::pathValidator()->getUrlIfValidWithoutAccessCheck($link)) && $url->isRouted()) {
        $generated_url = $url->toString(TRUE);
        $metadata = $metadata->merge($generated_url);
        $element->setAttribute('href', $generated_url->getGeneratedUrl());
      }
    }
    $result = new FilterProcessResult(Html::serialize($dom));
    return $result->merge($metadata);
  }

}