Added plugin for contextual filter for selecting 2 second level in bo…

…ok, used DI in Book Title block

modules/quanthub_book/src/Plugin/Block/QuanthubBookTitle.php

@@ -5,8 +5,8 @@
 use Drupal\Core\Block\BlockBase;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\Core\Routing\RouteMatchInterface;
-use Drupal\node\Entity\Node;
 use Drupal\node\NodeInterface;
+use Drupal\node\NodeStorageInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -19,6 +19,13 @@
  */
 class QuanthubBookTitle extends BlockBase implements ContainerFactoryPluginInterface {
 
+  /**
+   * The node storage controller.
+   *
+   * @var \Drupal\node\NodeStorageInterface
+   */
+  protected $nodeStorage;
+
   /**
    * The route match service.
    *
@@ -34,32 +41,34 @@ public static function create(ContainerInterface $container, array $configuratio
       $configuration,
       $plugin_id,
       $plugin_definition,
+      $container->get('entity_type.manager')->getStorage('node'),
       $container->get('current_route_match')
     );
   }
 
   /**
    * {@inheritdoc}
    */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, RouteMatchInterface $currentRouteMatch) {
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, NodeStorageInterface $node_storage, RouteMatchInterface $currentRouteMatch) {
     parent::__construct($configuration, $plugin_id, $plugin_definition);
     $this->currentRouteMatch = $currentRouteMatch;
+    $this->nodeStorage = $node_storage;
   }
 
   /**
    * {@inheritdoc}
    */
   public function build() {
     $node = $this->currentRouteMatch->getParameter('node');
+    $build = [];
 
     if ($node instanceof NodeInterface && $node->getType() == 'book' && !empty($node->book['bid'])) {
-      $book_main_node = Node::load($node->book['bid']);
+      $this->nodeStorage->load($node->book['bid']);
+      $build['quanthub_book_title'] = [
+        '#markup' => '<h1 class="quanthub_book_title display-3 xs:header-2 page-title mb-6">' . $book_main_node->getTitle() . '</h1>',
+      ];
     }
 
-    $build['quanthub_book_title'] = [
-      '#markup' => '<h1 class="quanthub_book_title display-3 xs:header-2 page-title mb-6">' . $book_main_node->getTitle() . '</h1>',
-    ];
-
     return $build;
   }
 

modules/quanthub_book/src/Plugin/views/argument_default/BookSecondLevelActive.php

@@ -0,0 +1,74 @@
+<?php
+
+namespace Drupal\quanthub_book\Plugin\views\argument_default;
+
+use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\node\NodeStorageInterface;
+use Drupal\node\Plugin\views\argument_default\Node;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Default argument plugin to get the current node's second level active page.
+ *
+ * @ViewsArgumentDefault(
+ *   id = "book_second_level_active",
+ *   title = @Translation("Book Second level active")
+ * )
+ */
+class BookSecondLevelActive extends Node {
+
+  /**
+   * The node storage controller.
+   *
+   * @var \Drupal\node\NodeStorageInterface
+   */
+  protected $nodeStorage;
+
+  /**
+   * Constructs a BookSecondLevelActive object.
+   *
+   * @param array $configuration
+   *   A configuration array containing information about the plugin instance.
+   * @param string $plugin_id
+   *   The plugin_id for the plugin instance.
+   * @param array $plugin_definition
+   *   The plugin implementation definition.
+   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
+   *   The route match.
+   * @param \Drupal\node\NodeStorageInterface $node_storage
+   *   The node storage controller.
+   */
+  public function __construct(array $configuration, $plugin_id, array $plugin_definition, RouteMatchInterface $route_match, NodeStorageInterface $node_storage) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition, $route_match);
+    $this->nodeStorage = $node_storage;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
+    return new static(
+      $configuration,
+      $plugin_id,
+      $plugin_definition,
+      $container->get('current_route_match'),
+      $container->get('entity_type.manager')->getStorage('node')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getArgument() {
+    // Use the argument_default_node plugin to get the nid argument.
+    $nid = parent::getArgument();
+    if (!empty($nid)) {
+      $node = $this->nodeStorage->load($nid);
+      // Get second level active book page.
+      if (isset($node->book['p2']) && $node->book['p2'] > 0) {
+        return $node->book['p2'];
+      }
+    }
+  }
+
+}