ContextualLinks.php

<?php

namespace Drupal\contextual\Element;

use Drupal\Component\Utility\Html;
use Drupal\Core\Render\Element\RenderElement;
use Drupal\Core\Url;

/**
 * Provides a contextual_links element.
 *
 * @RenderElement("contextual_links")
 */
class ContextualLinks extends RenderElement {
    
    /**
     * {@inheritdoc}
     */
    public function getInfo() {
        $class = get_class($this);
        return [
            '#pre_render' => [
                [
                    $class,
                    'preRenderLinks',
                ],
            ],
            '#theme' => 'links__contextual',
            '#links' => [],
            '#attributes' => [
                'class' => [
                    'contextual-links',
                ],
            ],
            '#attached' => [
                'library' => [
                    'contextual/drupal.contextual-links',
                ],
            ],
        ];
    }
    
    /**
     * Pre-render callback: Builds a renderable array for contextual links.
     *
     * @param array $element
     *   A renderable array containing a #contextual_links property, which is a
     *   keyed array. Each key is the name of the group of contextual links to
     *   render (based on the 'group' key in the *.links.contextual.yml files for
     *   all enabled modules). The value contains an associative array containing
     *   the following keys:
     *   - route_parameters: The route parameters passed to the url generator.
     *   - metadata: Any additional data needed in order to alter the link.
     *   @code
     *     array('#contextual_links' => array(
     *       'block' => array(
     *         'route_parameters' => array('block' => 'system.menu-tools'),
     *       ),
     *       'menu' => array(
     *         'route_parameters' => array('menu' => 'tools'),
     *       ),
     *     ))
     *   @endcode
     *
     * @return array
     *   A renderable array representing contextual links.
     */
    public static function preRenderLinks(array $element) {
        // Retrieve contextual menu links.
        $items = [];
        $contextual_links_manager = static::contextualLinkManager();
        foreach ($element['#contextual_links'] as $group => $args) {
            $args += [
                'route_parameters' => [],
                'metadata' => [],
            ];
            $items += $contextual_links_manager->getContextualLinksArrayByGroup($group, $args['route_parameters'], $args['metadata']);
        }
        // Transform contextual links into parameters suitable for links.html.twig.
        $links = [];
        foreach ($items as $class => $item) {
            $class = Html::getClass($class);
            $links[$class] = [
                'title' => $item['title'],
                'url' => Url::fromRoute(isset($item['route_name']) ? $item['route_name'] : '', isset($item['route_parameters']) ? $item['route_parameters'] : [], $item['localized_options']),
            ];
        }
        $element['#links'] = $links;
        // Allow modules to alter the renderable contextual links element.
        static::moduleHandler()->alter('contextual_links_view', $element, $items);
        // If there are no links, tell drupal_render() to abort rendering.
        if (empty($element['#links'])) {
            $element['#printed'] = TRUE;
        }
        return $element;
    }
    
    /**
     * Wraps the contextual link manager.
     *
     * @return \Drupal\Core\Menu\ContextualLinkManager
     */
    protected static function contextualLinkManager() {
        return \Drupal::service('plugin.manager.menu.contextual_link');
    }
    
    /**
     * Wraps the module handler.
     *
     * @return \Drupal\Core\Extension\ModuleHandlerInterface
     */
    protected static function moduleHandler() {
        return \Drupal::moduleHandler();
    }

}