Drupal Route with parameter

DisplayNode.php

<?php
//modules/custom/drupalbook/src/Controller/DisplayNode.php
 
namespace Drupal\drupalbook\Controller;
 
use Drupal\Core\Access\AccessResult;
use Drupal\node\NodeInterface;
 
/**
 * Provides route responses for the DrupalBook module.
 */
class DisplayNode {
 
  /**
   * Returns a simple page.
   *
   * @return array
   *   A simple renderable array.
   */
  public function content(NodeInterface $node) {
    $element = array(
      '#markup' => $node->body->value,
    );
    return $element;
  }
 
  /**
   * Checks access for this controller.
   */
  public function access(NodeInterface $node) {
    $user = \Drupal::currentUser();
    if ($node->getType() == 'article' && !in_array('authenticated', $user->getRoles())) {
      return AccessResult::forbidden();
    }
    return AccessResult::allowed();
  }
 
  /**
   * Returns a page title.
   */
  public function getTitle(NodeInterface $node) {
    return $node->getTitle();
  }
 
}

drupalbook.info.yml

name: DrupalBook
description: Custom module for learning Drupal
type: module
core: 8.x
core_version_requirement: ^8 || ^9
package: DrupalBook

drupalbook.routing.yml

drupalbook.display_node:
  path: '/display-node/{node}'
  defaults:
    _controller: '\Drupal\drupalbook\Controller\DisplayNode::content'
    _title_callback: '\Drupal\drupalbook\Controller\DisplayNode::getTitle'
  requirements:
    _custom_access: '\Drupal\drupalbook\Controller\DisplayNode::access'
  options:
    parameters:
      node:
        type: entity:node