Local Tasks Deriver for Facebook Widgets

FacebookWidgetsLocalTasks.php

<?php
/**
 * @file
 * Contains \Drupal\facebook_widgets\Plugin\Derivative\DynamicLocalTasks.
 */

namespace Drupal\facebook_widgets\Plugin\Derivative;

use Drupal\Component\Plugin\Derivative\DeriverBase;
use Drupal\Core\Menu\LocalTaskManager;
use Drupal\Core\Plugin\Discovery\ContainerDeriverInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Class DynamicLocalTasks
 *
 * @package Drupal\example\Plugin\Derivative
 */
class FacebookWidgetsLocalTasks extends DeriverBase implements ContainerDeriverInterface {

  /**
   * The base plugin ID.
   *
   * @var string
   */
  private $basePluginId;

  /**
   * The local task manager
   *
   * @var array
   */
  private $localTasks = array();

  private $called = false;

  public function __construct($basePluginId, LocalTaskManager $localTaskManager) {
    $this->basePluginId = $basePluginId;
    $this->localTasks = $localTaskManager->getDefinitions();
  }

  /**
   * {@inheritdoc}
   */
  public function getDerivativeDefinitions($base_plugin_definition) {
    // Implement dynamic logic to provide values for the same keys as in example.links.task.yml.
    $this->derivatives['facebook_widgets.list'] = $base_plugin_definition;

    $tasksList = $this->localTasks;

    foreach($tasksList as $task) {
      if($task['parent_id'] == 'facebook_widgets.list') {
        $this->derivatives['facebook_widgets.list']['route_name'] = 'facebook_comments.settings';
      	break;
      }
    }

    return $this->derivatives;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, $base_plugin_id) {
    return new static(
      $base_plugin_id,
      $container->get('plugin.manager.menu.local_task')
    );
  }

}