Is possible to find the "original" route while executing code from a widget?

I'm on D9.

I've a node edit form with a media field using the media library widget.

When a new media is added I'd need to run some custom code to replace one token, of the media path location, depending on the value of the node itself.

However, the route available with \Drupal::routeMatch() is media_library.ui and there is no node object available

I suppose this is correct, as the code is execute during the request "inside the media library widget".

Thus, i'm trying to find if is possibile somehow to get the "main\original" request from in that moment and the relative node object or if it is impossible. In the latter case, do you have idea if that objective is somehow possible?

To alter a widget form, Drupal invokes these hooks.

• hook_field_widget_complete_form_alter(&$field_widget_complete_form, \Drupal\Core\Form\FormStateInterface $form_state, $context) to alter the complete widget form
• hook_field_widget_single_element_form_alter(array &$element, \Drupal\Core\Form\FormStateInterface $form_state, array $context) to alter a single widget element

In both the cases, you can get the node to which the field using the Media library widget is attached using with code similar to the following one.

if ($context['widget']->getPluginId() == 'media_library_widget') {
  $field_definition = $context['items']->getFieldDefinition();
  if ($field_definition->getTargetEntityTypeId() == 'node') {
    $node = $context['items']->getEntity();
    // Use $node.
  }
}

If you are instead trying to alter the value of a token when it's used for that widget, that isn't possible, since the hook to alter the tokens (hook_tokens_alter()) only knows for which entity type the token is requested ($context['type']) and for which entity object ($context['data'][$context['type']]).

Here is my code which does a similar job - extracting the node from the entity browser parameters (However I am not sure which media path location are you going to change).

/**
 * Implements hook_form_BASE_FORM_ID_alter().
 */
function my_module_form_entity_browser_media_entity_browser_modal_form_alter(&$form, FormStateInterface $form_state) {
  // @todo Move that code to ClassResolver.
  /** @var \Drupal\entity_browser\Form\EntityBrowserForm $form_object */
  $form_object = $form_state->getFormObject();
  $eb = $form_object->getEntityBrowser();
  $eb_params = $eb->getAdditionalWidgetParameters();
  if (!isset($eb_params["path_parts"][1]) || !isset($eb_params["path_parts"][2])) {
    return;
  }

  if (!is_numeric($eb_params["path_parts"][2])) {
    return;
  }

  $params = [];
  try {
    $params = Url::fromUserInput(implode('/', $eb_params["path_parts"]))->getRouteParameters();
  }
  catch (Exception $exception) {
    Drupal::messenger()->addError($exception->getMessage());
  }

  $node = NULL;
  if (isset($params['node'])) {
    $node = Node::load($params['node']);
  }

  $group = NULL;
  if (isset($params['group'])) {
    $group = Group::load($params['group']);
  }

  if (empty($node) && empty($group)) {
    return;
  }

  $labels = [];
  $group_links = [];
  $group_urls = [];
  $gids = [];
  $gid = NULL;
  $form['#attributes']['data-parent_node'] = NULL;

  switch (!$node ? 'group' : 'node') {
    case 'group':
      $gid = $group->id();
      break;
    case 'node':
      $group_contents = GroupContent::loadByEntity($node);
      foreach ($group_contents as $group_content) {
        $group = $group_content->getGroup();
        $gids[] = $group->id();
        $labels[] = $group->label();
        $group_urls[] = $group->toUrl()->toString();
        $group_links[] = $group->toLink($group->label())->toString();
      }

      $form['#attributes']['data-parent_node'] = $node->id();

      $gid = reset($gids);
      break;
  }

  $form['#attributes']['data-parent_group_names'] = json_encode($labels);
  $form['#attributes']['data-parent_group_urls'] = json_encode($group_urls);
  $form['#attributes']['data-parent_group_links'] = json_encode($group_links);
  $form['#attributes']['data-parent_group_ids'] = json_encode($gids);
  $form['#attributes']['data-parent_group_id'] = $gid;
}