How can I confirm a path is internal?

Question

In my theme's theme file I'm using preprocess_node to create variables for a node based on the section of my site its in, and that's figured out by checking the path's alias.

So for example a path like: /events/this_is_my_node

It'll see that this node is in the events section of the site and the variables provided to the twig template facilitate theming the node page based on the section it's in.

Everything works great if the node and the node that's the section's landing page have their aliases generated, but if they don't, I get an error like:

UnexpectedValueException: External URLs do not have internal route parameters. in Drupal\Core\Url->getRouteParameters() (line 583 of core/lib/Drupal/Core/Url.php).

So basically I'm trying to figure out a conditional I can use so that I'm only getting Route parameters from a path it recognizes as being internal and should something go wrong and a path alias isn't set I don't get a WSOD.

I've tried using UrlHelper::isExternal but that doesn't seem to help as it just seems to look at the path structure to determine if its external or not vs actually check the page.

This is my code:

function THEME_preprocess_node(&$variables) {
  $route_name = \Drupal::routeMatch()->getRouteName();
  $variables['#cache']['contexts'][] = 'route.name.is_layout_builder_ui';
  $internal_path = \Drupal::service('path.current')->getPath();
  $current_path = \Drupal::service('path_alias.manager')->getAliasByPath($internal_path);
  $variables['current_path'] = $current_path;
  $variables['internal_path'] = $internal_path;
  $int_exp = explode("/", $current_path);
  $alias = \Drupal::service('path_alias.manager')->getPathByAlias($int_exp[1]);
  $is_layout = false;
  if ($route_name ) {
    $node = $variables['node'];
    // check if layout builder is active
    if (isset($int_exp[3])) {
      if ($int_exp[3] == 'layout' or $int_exp[1] == 'layout_builder')
      {
        $is_layout = true;
      }
    }

    if (isset($internal_path) && !$is_layout) {
      $params = Url::fromUri("internal:/" . $alias)->getRouteParameters();
      $entity_type = key($params);
      if (isset($entity_type)) {
        $node = \Drupal::entityTypeManager()->getStorage($entity_type)->load($params[$entity_type]);
        $variables['section_nid'] = $node->nid->value;
        $variables['is_site_section'] = false;
        if ($node->type->target_id == 'sections') {
          $variables['is_site_section'] = true;
          $variables['current_section'] = $node->field_section_machine_name->value;
          $variables['current_section_title'] = $node->title->value;
        }
      }
    }

  }
}

Answer 1

You should not check for internal. An url like internal:/robots.txt is internal, but it is no route and has no route parameters.

So before you do Url::getRouteParameters() you should check for Url::isRouted()