SvgExtractor.php

<?php

declare (strict_types=1);
namespace Drupal\Core\Theme\Plugin\IconExtractor;

use Drupal\Component\Render\FormattableMarkup;
use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\Core\Template\Attribute;
use Drupal\Core\Theme\Icon\Attribute\IconExtractor;
use Drupal\Core\Theme\Icon\IconDefinition;
use Drupal\Core\Theme\Icon\IconDefinitionInterface;
use Drupal\Core\Theme\Icon\IconExtractorWithFinder;
use Drupal\Core\Theme\Icon\IconPackExtractorForm;

/**
 * Plugin implementation of the icon_extractor.
 *
 * This extractor needs the file content, only local SVG are allowed to avoid
 * any security risk. For remote sources, `path` extractor must be used or
 * `svg_sprite` for remote sprite.
 *
 * @internal
 *   This API is experimental.
 */
class SvgExtractor extends IconExtractorWithFinder {
  
  /**
   * {@inheritdoc}
   */
  public function discoverIcons() : array {
    // Check is included in getFilesFromSources(), but we need to disallow
    // remote sources before.
    $this->checkRequiredConfigSources();
    $this->configuration['config']['sources'] = array_filter($this->configuration['config']['sources'], function ($source) {
      return empty(parse_url($source, PHP_URL_SCHEME));
    });
    if (empty($this->configuration['config']['sources'])) {
      return [];
    }
    $files = $this->getFilesFromSources();
    if (empty($files)) {
      return [];
    }
    $icons = [];
    foreach ($files as $file) {
      if (!isset($file['absolute_path']) || empty($file['absolute_path'])) {
        continue;
      }
      $id = IconDefinition::createIconId($this->configuration['id'], $file['icon_id']);
      $icons[$id] = [
        'absolute_path' => $file['absolute_path'],
        'source' => $file['source'],
        'group' => $file['group'] ?? NULL,
      ];
    }
    return $icons;
  }
  
  /**
   * {@inheritdoc}
   */
  public function loadIcon(array $icon_data) : ?IconDefinitionInterface {
    if (!isset($icon_data['icon_id']) || !isset($icon_data['source']) || !isset($icon_data['absolute_path'])) {
      return NULL;
    }
    if (!($svg_data = $this->extractSvg($icon_data['absolute_path']))) {
      return NULL;
    }
    return $this->createIcon($icon_data['icon_id'], $icon_data['source'], $icon_data['group'] ?? NULL, $svg_data);
  }
  
  /**
   * Extract svg values, simply exclude parent <svg>.
   *
   * @param string $source
   *   Local path or url to the svg file.
   *
   * @return array|null
   *   The SVG `content` as string and `viewbox` value if any.
   */
  private function extractSvg(string $source) : ?array {
    if (!($content = $this->iconFinder
      ->getFileContents($source))) {
      return NULL;
    }
    libxml_use_internal_errors(TRUE);
    if (!($svg = simplexml_load_string((string) $content))) {
      // @todo do we need to log a warning with the xml error?
      return NULL;
    }
    $return = [
      'content' => '',
      'attributes' => new Attribute(),
    ];
    foreach ($svg as $child) {
      $return['content'] .= $child->asXML();
    }
    if (empty($return['content'])) {
      return NULL;
    }
    // Content contain xml data and will be printed, we need to not escape it
    // for rendering.
    $return['content'] = new FormattableMarkup($return['content'], []);
    // Add svg attributes to be available in the template.
    foreach ($svg->attributes() as $name => $value) {
      $return['attributes']->setAttribute($name, (string) $value);
    }
    return $return;
  }

}