book.module

<?php

/**
 * @file
 * Allows users to create and organize related content in an outline.
 */

use Drupal\book\BookManager;
use Drupal\book\BookManagerInterface;
use Drupal\Component\Utility\String;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Render\Element;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\node\NodeInterface;
use Drupal\node\NodeTypeInterface;
use Drupal\Core\Language\LanguageInterface;
use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
use Drupal\Core\Template\Attribute;

/**
 * Implements hook_help().
 */
function book_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.book':
      $output = '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Book module is used for creating structured, multi-page content, such as site resource guides, manuals, and wikis. It allows you to create content that has chapters, sections, subsections, or any similarly-tiered structure. For more information, see the <a href="!book">online documentation for the Book module</a>.', array('!book' => 'https://drupal.org/documentation/modules/book')) . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('Adding and managing book content') . '</dt>';
      $output .= '<dd>' . t('You can assign separate permissions for <em>creating new books</em> as well as <em>creating</em>, <em>editing</em> and <em>deleting</em> book content. Users with the <em>Administer book outlines</em> permission can add <em>any</em> type of content to a book by selecting the appropriate book outline while editing the content. They can also view a list of all books, and edit and rearrange section titles on the <a href="!admin-book">Book administration page</a>.', array('!admin-book' => \Drupal::url('book.admin'))) . '</dd>';
      $output .= '<dt>' . t('Book navigation') . '</dt>';
      $output .= '<dd>' . t("Book pages have a default book-specific navigation block. This navigation block contains links that lead to the previous and next pages in the book, and to the level above the current page in the book's structure. This block can be enabled on the <a href='!admin-block'>Blocks administration page</a>. For book pages to show up in the book navigation, they must be added to a book outline.", array('!admin-block' => \Drupal::url('block.admin_display'))) . '</dd>';
      $output .= '<dt>' . t('Collaboration') . '</dt>';
      $output .= '<dd>' . t('Books can be created collaboratively, as they allow users with appropriate permissions to add pages into existing books, and add those pages to a custom table of contents.') . '</dd>';
      $output .= '<dt>' . t('Printing books') . '</dt>';
      $output .= '<dd>' . t("Users with the <em>View printer-friendly books</em> permission can select the <em>printer-friendly version</em> link visible at the bottom of a book page's content to generate a printer-friendly display of the page and all of its subsections.") . '</dd>';
      $output .= '</dl>';
      return $output;

    case 'book.admin':
      return '<p>' . t('The book module offers a means to organize a collection of related content pages, collectively known as a book. When viewed, this content automatically displays links to adjacent book pages, providing a simple navigation system for creating and reviewing structured content.') . '</p>';

    case 'book.outline':
      return '<p>' . t('The outline feature allows you to include pages in the <a href="!book">Book hierarchy</a>, as well as move them within the hierarchy or to <a href="!book-admin">reorder an entire book</a>.', array('!book' => \Drupal::url('book.render'), '!book-admin' => \Drupal::url('book.admin'))) . '</p>';
  }
}

/**
 * Implements hook_theme().
 */
function book_theme() {
  return array(
    'book_navigation' => array(
      'variables' => array('book_link' => NULL),
      'template' => 'book-navigation',
    ),
    'book_tree' => array(
      'render element' => 'tree',
      'template' => 'book-tree',
    ),
    'book_link' => array(
      'render element' => 'element',
    ),
    'book_export_html' => array(
      'variables' => array('title' => NULL, 'contents' => NULL, 'depth' => NULL),
      'template' => 'book-export-html',
    ),
    'book_admin_table' => array(
      'render element' => 'form',
      'file' => 'book.admin.inc',
    ),
    'book_all_books_block' => array(
      'render element' => 'book_menus',
      'template' => 'book-all-books-block',
    ),
    'book_node_export_html' => array(
      'variables' => array('node' => NULL, 'children' => NULL),
      'template' => 'book-node-export-html',
    ),
  );
}

/**
 * Implements hook_permission().
 */
function book_permission() {
  return array(
    'administer book outlines' => array(
      'title' => t('Administer book outlines'),
    ),
    'create new books' => array(
      'title' => t('Create new books'),
    ),
    'add content to books' => array(
      'title' => t('Add content and child pages to books'),
    ),
    'access printer-friendly version' => array(
      'title' => t('View printer-friendly books'),
      'description' => t('View a book page and all of its sub-pages as a single document for ease of printing. Can be performance heavy.'),
    ),
  );
}

/**
 * Implements hook_entity_type_build().
 */
function book_entity_type_build(array &$entity_types) {
  /** @var $entity_types \Drupal\Core\Entity\EntityTypeInterface[] */
  $entity_types['node']
    ->setFormClass('book_outline', 'Drupal\book\Form\BookOutlineForm')
    ->setLinkTemplate('book-outline-form', 'book.outline')
    ->setLinkTemplate('book-remove-form', 'book.remove');
}

/**
 * Implements hook_node_links_alter().
 */
function book_node_links_alter(array &$node_links, NodeInterface $node, array &$context) {
  if ($context['view_mode'] != 'rss') {
    $account = \Drupal::currentUser();

    if (isset($node->book['depth'])) {
      if ($context['view_mode'] == 'full' && node_is_page($node)) {
        $child_type = \Drupal::config('book.settings')->get('child_type');
        $access_control_handler = \Drupal::entityManager()->getAccessControlHandler('node');
        if (($account->hasPermission('add content to books') || $account->hasPermission('administer book outlines')) && $access_control_handler->createAccess($child_type) && $node->isPublished() && $node->book['depth'] < BookManager::BOOK_MAX_DEPTH) {
          $links['book_add_child'] = array(
            'title' => t('Add child page'),
            'href' => 'node/add/' . $child_type,
            'query' => array('parent' => $node->id()),
          );
        }

        if ($account->hasPermission('access printer-friendly version')) {
          $links['book_printer'] = array(
            'title' => t('Printer-friendly version'),
            'href' => 'book/export/html/' . $node->id(),
            'attributes' => array('title' => t('Show a printer-friendly version of this book page and its sub-pages.'))
          );
        }
      }
    }

    if (!empty($links)) {
      $node_links['book'] = array(
        '#theme' => 'links__node__book',
        '#links' => $links,
        '#attributes' => array('class' => array('links', 'inline')),
      );
    }
  }
}

/**
 * Implements hook_form_BASE_FORM_ID_alter() for node_form().
 *
 * Adds the book form element to the node form.
 *
 * @see book_pick_book_nojs_submit()
 */
function book_form_node_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  $node = $form_state['controller']->getEntity();
  $account = \Drupal::currentUser();
  $access = $account->hasPermission('administer book outlines');
  if (!$access) {
    if ($account->hasPermission('add content to books') && ((!empty($node->book['bid']) && !$node->isNew()) || book_type_is_allowed($node->getType()))) {
      // Already in the book hierarchy, or this node type is allowed.
      $access = TRUE;
    }
  }

  if ($access) {
    $collapsed = !($node->isNew() && !empty($node->book['pid']));
    $form = \Drupal::service('book.manager')->addFormElements($form, $form_state, $node, $account, $collapsed);
    // Since the "Book" dropdown can't trigger a form submission when
    // JavaScript is disabled, add a submit button to do that. book.admin.css hides
    // this button when JavaScript is enabled.
    $form['book']['pick-book'] = array(
      '#type' => 'submit',
      '#value' => t('Change book (update list of parents)'),
      '#submit' => array('book_pick_book_nojs_submit'),
      '#weight' => 20,
      '#attached' => array(
        'css' => array(drupal_get_path('module', 'book') . '/css/book.admin.css'),
      ),
    );
    $form['#entity_builders'][] = 'book_node_builder';
  }
}

/**
 * Entity form builder to add the book information to the node.
 *
 * @todo: Remove this in favor of an entity field.
 */
function book_node_builder($entity_type, NodeInterface $entity, &$form, FormStateInterface $form_state) {
  $entity->book = $form_state->getValue('book');

  // Always save a revision for non-administrators.
  if (!empty($entity->book['bid']) && !\Drupal::currentUser()->hasPermission('administer nodes')) {
    $entity->setNewRevision();
  }
}

/**
 * Form submission handler for node_form().
 *
 * This handler is run when JavaScript is disabled. It triggers the form to
 * rebuild so that the "Parent item" options are changed to reflect the newly
 * selected book. When JavaScript is enabled, the submit button that triggers
 * this handler is hidden, and the "Book" dropdown directly triggers the
 * book_form_update() Ajax callback instead.
 *
 * @see book_form_update()
 * @see book_form_node_form_alter()
 */
function book_pick_book_nojs_submit($form, FormStateInterface $form_state) {
  $node = $form_state['controller']->getEntity();
  $node->book = $form_state->getValue('book');
  $form_state['rebuild'] = TRUE;
}

/**
 * Renders a new parent page select element when the book selection changes.
 *
 * This function is called via Ajax when the selected book is changed on a node
 * or book outline form.
 *
 * @return
 *   The rendered parent page select element.
 */
function book_form_update($form, FormStateInterface $form_state) {
  return $form['book']['pid'];
}

/**
 * Implements hook_ENTITY_TYPE_load() for node entities.
 */
function book_node_load($nodes) {
  /** @var \Drupal\book\BookManagerInterface $book_manager */
  $book_manager = \Drupal::service('book.manager');
  $links = $book_manager->loadBookLinks(array_keys($nodes), FALSE);
  foreach ($links as $record) {
    $nodes[$record['nid']]->book = $record;
    $nodes[$record['nid']]->book['link_path'] = 'node/' . $record['nid'];
    $nodes[$record['nid']]->book['link_title'] = $nodes[$record['nid']]->label();
  }
}

/**
 * Implements hook_ENTITY_TYPE_view() for node entities.
 */
function book_node_view(array &$build, EntityInterface $node, EntityViewDisplayInterface $display, $view_mode) {
  if ($view_mode == 'full') {
    if (!empty($node->book['bid']) && empty($node->in_preview)) {
      $book_navigation = array( '#theme' => 'book_navigation', '#book_link' => $node->book);
      $build['book_navigation'] = array(
        '#markup' => drupal_render($book_navigation),
        '#weight' => 100,
        '#attached' => array(
          'css' => array(
            drupal_get_path('module', 'book') . '/css/book.theme.css',
          ),
        ),
      );
    }
  }
}

/**
 * Implements hook_ENTITY_TYPE_presave() for node entities.
 */
function book_node_presave(EntityInterface $node) {
  // Make sure a new node gets a new menu link.
  if ($node->isNew()) {
    $node->book['nid'] = NULL;
  }
}

/**
 * Implements hook_ENTITY_TYPE_insert() for node entities.
 */
function book_node_insert(EntityInterface $node) {
  /** @var \Drupal\book\BookManagerInterface $book_manager */
  $book_manager = \Drupal::service('book.manager');
  $book_manager->updateOutline($node);
}

/**
 * Implements hook_ENTITY_TYPE_update() for node entities.
 */
function book_node_update(EntityInterface $node) {
  /** @var \Drupal\book\BookManagerInterface $book_manager */
  $book_manager = \Drupal::service('book.manager');
  $book_manager->updateOutline($node);
}

/**
 * Implements hook_ENTITY_TYPE_predelete() for node entities.
 */
function book_node_predelete(EntityInterface $node) {
  if (!empty($node->book['bid'])) {
    /** @var \Drupal\book\BookManagerInterface $book_manager */
    $book_manager = \Drupal::service('book.manager');
    $book_manager->deleteFromBook($node->book['nid']);
  }
}

/**
 * Implements hook_node_prepare_form().
 */
function book_node_prepare_form(NodeInterface $node, $operation, FormStateInterface $form_state) {
  /** @var \Drupal\book\BookManagerInterface $book_manager */
  $book_manager = \Drupal::service('book.manager');

  // Prepare defaults for the add/edit form.
  $account = \Drupal::currentUser();
  if (empty($node->book) && ($account->hasPermission('add content to books') || $account->hasPermission('administer book outlines'))) {
    $node->book = array();

    $query = \Drupal::request()->query;
    if ($node->isNew() && !is_null($query->get('parent')) && is_numeric($query->get('parent'))) {
      // Handle "Add child page" links:
      $parent = $book_manager->loadBookLink($query->get('parent'), TRUE);

      if ($parent && $parent['access']) {
        $node->book['bid'] = $parent['bid'];
        $node->book['pid'] = $parent['nid'];
      }
    }
    // Set defaults.
    $node_ref = !$node->isNew() ? $node->id() : 'new';
    $node->book += $book_manager->getLinkDefaults($node_ref);
  }
  else {
    if (isset($node->book['bid']) && !isset($node->book['original_bid'])) {
      $node->book['original_bid'] = $node->book['bid'];
    }
  }
  // Find the depth limit for the parent select.
  if (isset($node->book['bid']) && !isset($node->book['parent_depth_limit'])) {
    $node->book['parent_depth_limit'] = $book_manager->getParentDepthLimit($node->book);
  }
}

/**
 * Implements hook_form_FORM_ID_alter() for node_delete_confirm().
 *
 * Alters the confirm form for a single node deletion.
 *
 * @see node_delete_confirm()
 */
function book_form_node_delete_confirm_alter(&$form, FormStateInterface $form_state) {
  $node = node_load($form['nid']['#value']);

  if (isset($node->book) && $node->book['has_children']) {
    $form['book_warning'] = array(
      '#markup' => '<p>' . t('%title is part of a book outline, and has associated child pages. If you proceed with deletion, the child pages will be relocated automatically.', array('%title' => $node->label())) . '</p>',
      '#weight' => -10,
    );
  }
}

/**
 * Prepares variables for book listing block templates.
 *
 * Default template: book-all-books-block.html.twig.
 *
 * All non-renderable elements are removed so that the template has full access
 * to the structured data but can also simply iterate over all elements and
 * render them (as in the default template).
 *
 * @param array $variables
 *   An associative array containing the following key:
 *   - book_menus: An associative array containing renderable menu links for all
 *     book menus.
 */
function template_preprocess_book_all_books_block(&$variables) {
  // Remove all non-renderable elements.
  $elements = $variables['book_menus'];
  $variables['book_menus'] = array();
  foreach (Element::children($elements) as $index) {
    $variables['book_menus'][] = array(
      'id' => $index,
      'menu' => $elements[$index],
      'title' => $elements[$index]['#book_title'],
    );
  }
}

/**
 * Prepares variables for book navigation templates.
 *
 * Default template: book-navigation.html.twig.
 *
 * @param array $variables
 *   An associative array containing the following key:
 *   - book_link: An associative array of book link properties.
 *     Properties used: bid, link_title, depth, pid, nid.
 */
function template_preprocess_book_navigation(&$variables) {
  $book_link = $variables['book_link'];

  // Provide extra variables for themers. Not needed by default.
  $variables['book_id'] = $book_link['bid'];
  $variables['book_title'] = String::checkPlain($book_link['link_title']);
  $variables['book_url'] = \Drupal::url('entity.node.canonical', array('node' => $book_link['bid']));
  $variables['current_depth'] = $book_link['depth'];
  $variables['tree'] = '';

  /** @var \Drupal\book\BookOutline $book_outline */
  $book_outline = \Drupal::service('book.outline');

  if ($book_link['nid']) {
    $variables['tree'] = $book_outline->childrenLinks($book_link);

    $build = array();

    if ($prev = $book_outline->prevLink($book_link)) {
      $prev_href = \Drupal::url('entity.node.canonical', array('node' => $prev['nid']));
      $build['#attached']['drupal_add_html_head_link'][][] = array(
        'rel' => 'prev',
        'href' => $prev_href,
      );
      $variables['prev_url'] = $prev_href;
      $variables['prev_title'] = String::checkPlain($prev['title']);
    }

    /** @var \Drupal\book\BookManagerInterface $book_manager */
    $book_manager = \Drupal::service('book.manager');
    if ($book_link['pid'] && $parent = $book_manager->loadBookLink($book_link['pid'])) {
      $parent_href = \Drupal::url('entity.node.canonical', array('node' => $book_link['pid']));
      $build['#attached']['drupal_add_html_head_link'][][] = array(
        'rel' => 'up',
        'href' => $parent_href,
      );
      $variables['parent_url'] = $parent_href;
      $variables['parent_title'] = String::checkPlain($parent['title']);
    }

    if ($next = $book_outline->nextLink($book_link)) {
      $next_href = \Drupal::url('entity.node.canonical', array('node' => $next['nid']));
      $build['#attached']['drupal_add_html_head_link'][][] = array(
        'rel' => 'next',
        'href' => $next_href,
      );
      $variables['next_url'] = $next_href;
      $variables['next_title'] = String::checkPlain($next['title']);
    }
  }

  if (!empty($build)) {
    drupal_render($build);
  }

  $variables['has_links'] = FALSE;
  // Link variables to filter for values and set state of the flag variable.
  $links = array('prev_url', 'prev_title', 'parent_url', 'parent_title', 'next_url', 'next_title');
  foreach ($links as $link) {
    if (isset($variables[$link])) {
      // Flag when there is a value.
      $variables['has_links'] = TRUE;
    }
    else {
      // Set empty to prevent notices.
      $variables[$link] = '';
    }
  }
}

/**
 * Prepares variables for book export templates.
 *
 * Default template: book-export-html.html.twig.
 *
 * @param array $variables
 *   An associative array containing:
 *   - title: The title of the book.
 *   - contents: Output of each book page.
 *   - depth: The max depth of the book.
 */
function template_preprocess_book_export_html(&$variables) {
  global $base_url;
  $language_interface = \Drupal::languageManager()->getCurrentLanguage();

  $variables['title'] = String::checkPlain($variables['title']);
  $variables['base_url'] = $base_url;
  $variables['language'] = $language_interface;
  $variables['language_rtl'] = ($language_interface->direction == LanguageInterface::DIRECTION_RTL);
  $variables['head'] = drupal_get_html_head();

  // HTML element attributes.
  $attributes = array();
  $attributes['lang'] = $language_interface->id;
  $attributes['dir'] = $language_interface->direction ? 'rtl' : 'ltr';
  $variables['html_attributes'] = new Attribute($attributes);
}

/**
 * Prepares variables for single node export templates.
 *
 * Default template: book-node-export-html.html.twig.
 *
 * @param array $variables
 *   An associative array containing the following keys:
 *   - node: The node that will be output.
 *   - children: All the rendered child nodes within the current node. Defaults
 *     to an empty string.
 */
function template_preprocess_book_node_export_html(&$variables) {
  $variables['depth'] = $variables['node']->book['depth'];
  $variables['title'] = String::checkPlain($variables['node']->label());
  $variables['content'] = $variables['node']->rendered;
}

/**
 * Implements template_preprocess_HOOK() for theme_book_tree().
 */
function template_preprocess_book_tree(&$variables) {
  $variables['tree'] = $variables['tree']['#children'];
}

/**
 * Returns HTML for a book link and subtree.
 *
 * @param array $variables
 *   An associative array containing:
 *   - element: Structured array data for a book link.
 *
 * @ingroup themeable
 */
function theme_book_link(array $variables) {
  $element = $variables['element'];
  $sub_menu = '';

  if ($element['#below']) {
    $sub_menu = drupal_render($element['#below']);
  }
  $element['#localized_options']['set_active_class'] = TRUE;
  $output = l($element['#title'], $element['#href'], $element['#localized_options']);
  return '<li' . new Attribute($element['#attributes']) . '>' . $output . $sub_menu . "</li>\n";
}

/**
 * Determines if a given node type is in the list of types allowed for books.
 *
 * @param string $type
 *   A node type.
 *
 * @return bool
 *   A Boolean TRUE if the node type can be included in books; otherwise, FALSE.
 */
function book_type_is_allowed($type) {
  return in_array($type, \Drupal::config('book.settings')->get('allowed_types'));
}

/**
 * Implements hook_ENTITY_TYPE_update() for node_type entities.
 *
 * Updates book.settings configuration object if the machine-readable name of a
 * node type is changed.
 */
function book_node_type_update(NodeTypeInterface $type) {
  if ($type->getOriginalId() != $type->id()) {
    $config = \Drupal::config('book.settings');
    // Update the list of node types that are allowed to be added to books.
    $allowed_types = $config->get('allowed_types');
    $old_key = array_search($type->getOriginalId(), $allowed_types);

    if ($old_key !== FALSE) {
      $allowed_types[$old_key] = $type->id();
      // Ensure that the allowed_types array is sorted consistently.
      // @see BookSettingsForm::submitForm()
      sort($allowed_types);
      $config->set('allowed_types', $allowed_types);
    }

    // Update the setting for the "Add child page" link.
    if ($config->get('child_type') == $type->getOriginalId()) {
      $config->set('child_type', $type->id());
    }
    $config->save();
  }
}