Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\help\Plugin\Block;
Chris@0: 
Chris@0: use Drupal\Core\Block\BlockBase;
Chris@0: use Drupal\Core\Cache\Cache;
Chris@0: use Drupal\Core\Extension\ModuleHandlerInterface;
Chris@0: use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
Chris@0: use Drupal\Core\Routing\RouteMatchInterface;
Chris@0: use Symfony\Component\DependencyInjection\ContainerInterface;
Chris@0: use Symfony\Component\HttpFoundation\Request;
Chris@0: 
Chris@0: /**
Chris@0:  * Provides a 'Help' block.
Chris@0:  *
Chris@0:  * @Block(
Chris@0:  *   id = "help_block",
Chris@14:  *   admin_label = @Translation("Help"),
Chris@14:  *   forms = {
Chris@14:  *     "settings_tray" = FALSE,
Chris@14:  *   },
Chris@0:  * )
Chris@0:  */
Chris@0: class HelpBlock extends BlockBase implements ContainerFactoryPluginInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * The module handler.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Extension\ModuleHandlerInterface
Chris@0:    */
Chris@0:   protected $moduleHandler;
Chris@0: 
Chris@0:   /**
Chris@0:    * The current request.
Chris@0:    *
Chris@0:    * @var \Symfony\Component\HttpFoundation\Request
Chris@0:    */
Chris@0:   protected $request;
Chris@0: 
Chris@0:   /**
Chris@0:    * The current route match.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Routing\RouteMatchInterface
Chris@0:    */
Chris@0:   protected $routeMatch;
Chris@0: 
Chris@0:   /**
Chris@0:    * Creates a HelpBlock instance.
Chris@0:    *
Chris@0:    * @param array $configuration
Chris@0:    *   A configuration array containing information about the plugin instance.
Chris@0:    * @param string $plugin_id
Chris@0:    *   The plugin_id for the plugin instance.
Chris@0:    * @param mixed $plugin_definition
Chris@0:    *   The plugin implementation definition.
Chris@0:    * @param \Symfony\Component\HttpFoundation\Request $request
Chris@0:    *   The current request.
Chris@0:    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
Chris@0:    *   The module handler.
Chris@0:    * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
Chris@0:    *   The current route match.
Chris@0:    */
Chris@0:   public function __construct(array $configuration, $plugin_id, $plugin_definition, Request $request, ModuleHandlerInterface $module_handler, RouteMatchInterface $route_match) {
Chris@0:     parent::__construct($configuration, $plugin_id, $plugin_definition);
Chris@0: 
Chris@0:     $this->request = $request;
Chris@0:     $this->moduleHandler = $module_handler;
Chris@0:     $this->routeMatch = $route_match;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
Chris@0:     return new static(
Chris@0:       $configuration,
Chris@0:       $plugin_id,
Chris@0:       $plugin_definition,
Chris@0:       $container->get('request_stack')->getCurrentRequest(),
Chris@0:       $container->get('module_handler'),
Chris@0:       $container->get('current_route_match')
Chris@0:     );
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function build() {
Chris@0:     // Do not show on a 403 or 404 page.
Chris@0:     if ($this->request->attributes->has('exception')) {
Chris@0:       return [];
Chris@0:     }
Chris@0: 
Chris@0:     $implementations = $this->moduleHandler->getImplementations('help');
Chris@0:     $build = [];
Chris@0:     $args = [
Chris@0:       $this->routeMatch->getRouteName(),
Chris@0:       $this->routeMatch,
Chris@0:     ];
Chris@0:     foreach ($implementations as $module) {
Chris@0:       // Don't add empty strings to $build array.
Chris@0:       if ($help = $this->moduleHandler->invoke($module, 'help', $args)) {
Chris@0:         // Convert strings to #markup render arrays so that they will XSS admin
Chris@0:         // filtered.
Chris@0:         $build[] = is_array($help) ? $help : ['#markup' => $help];
Chris@0:       }
Chris@0:     }
Chris@0:     return $build;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function getCacheContexts() {
Chris@0:     return Cache::mergeContexts(parent::getCacheContexts(), ['route']);
Chris@0:   }
Chris@0: 
Chris@0: }