onlyone.module in Allow a content type only once (Only One) 7

Allows to define if a content type must have more than one node in the site.

File

onlyone.module

<?php

/**
 * @file
 * Allows to define if a content type must have more than one node in the site.
 */
define('ONLYONE_FORMAT_INITIAL_DRUSH', ' (');
define('ONLYONE_FORMAT_FINAL_DRUSH', ')');
define('ONLYONE_FORMAT_INITIAL_ADMIN', ' <strong>(');
define('ONLYONE_FORMAT_FINAL_ADMIN', ') </strong>');

/**
 * Implements hook_help().
 */
function onlyone_help($path, $arg) {
  switch ($path) {

    // Main module help.
    case 'admin/help#onlyone':

      // The route onlyone/add exists or not?
      if (variable_get('onlyone_new_menu_entry')) {

        // Creating the link.
        $onlyone_add_page = t('<a href="@link">Add content (Only One)</a> page', array(
          '@link' => url('onlyone/add'),
        ));
      }
      else {

        // As the route doesn't exists we use a string.
        $onlyone_add_page = t('<em>Add content (Only One)</em> page (onlyone/add)');
      }

      // Array with routes to replace.
      $routes = array(
        '@settings-page' => url('admin/config/content/onlyone/settings'),
        '@content' => url('admin/content'),
        '!onlyone_add_page' => $onlyone_add_page,
        '@add-content' => url('node/add'),
      );
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The Allow a content type only once (Only One) module allows the creation of Only One content per language in the selected content types for this configuration.') . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('Configuring content types') . '</dt>';
      $output .= '<dd>' . t('To configure the content types to allow for Only One content per language, visit the <a href="@config-page">Only One</a> page, in the <em>Available content types for Only One</em> section and <em>check</em> the content types that should have Only One content per language. For this you need the <em>Administer Only One</em> permission.', array(
        '@config-page' => url('admin/config/content/onlyone'),
      )) . '</dd>';
      $output .= '<dt>' . t('Configuring module settings') . '</dt>';
      $output .= '<dd>' . t('To configure the module settings visit the <a href="@settings-page">Settings</a> page, if you want to have the configured content types in a new menu entry named <em>Add content (Only One)</em> you must check the option <em>Show configured content types in a new menu entry?</em>, the new menu link will be available in the <a href="@content">Content</a> page as an action link to the !onlyone_add_page, then the <a href="@add-content">Add content</a> page will show the not configured content types. For this you need the <em>Administer Only One</em> permission.', $routes) . '</dd>';
      $output .= '<dt>' . t('Creating content') . '</dt>';
      $output .= '<dd>' . t('Once you try to <a href="@add-content">Add content</a>, if the chosen content type is configured to have Only One content and it already has one content created in the actual language, you will be redirected to <em>edit</em> the content, otherwise, you will go to create a new onw.', array(
        '@add-content' => url('node/add'),
      )) . '</dd>';
      $output .= '</dl>';
      return $output;
  }
}

/**
 * Implements hook_admin_paths().
 */
function onlyone_admin_paths() {
  if (variable_get('node_admin_theme')) {
    $paths = array(
      'onlyone/add' => TRUE,
    );
    return $paths;
  }
}

/**
 * Implements hook_menu().
 */
function onlyone_menu() {
  $items['admin/config/content/onlyone'] = array(
    'title' => 'Only One',
    'description' => 'Configure the content types to allow for Only One node per language.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array(
      'config_content_types',
    ),
    'access arguments' => array(
      'administer onlyone',
    ),
    'type' => MENU_NORMAL_ITEM,
    'file' => 'onlyone.admin.inc',
  );
  $items['admin/config/content/onlyone/default'] = array(
    'title' => 'Only One',
    'description' => 'Configure the content types to allow for Only One node per language.',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => 2,
  );
  $items['admin/config/content/onlyone/settings'] = array(
    'title' => 'Settings',
    'description' => 'Only One Settings.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array(
      'onlyone_admin_settings',
    ),
    'access arguments' => array(
      'administer onlyone',
    ),
    'type' => MENU_LOCAL_TASK,
    'file' => 'onlyone.admin.inc',
    'weight' => 2,
  );
  if (variable_get('onlyone_new_menu_entry')) {
    $items['onlyone/add'] = array(
      'title' => 'Add content (Only One)',
      'page callback' => 'onlyone_add_page',
      'access callback' => '_node_add_access',
      'file' => 'onlyone.pages.inc',
      'menu_name' => 'management',
      'type' => MENU_NORMAL_ITEM,
      'weight' => -1,
    );
  }
  return $items;
}

/**
 * Implements hook_menu_link_alter().
 */
function onlyone_menu_link_alter(&$item) {
  if ($item['page callback'] == 'onlyone_add_page') {

    // Assigning /admin/content as parent.
    $item['plid'] = 9;
  }
}

/**
 * Implements hook_menu_local_tasks_alter().
 */
function onlyone_menu_local_tasks_alter(&$data, $router_item, $root_path) {

  // Add action link to 'onlyone/add' on 'admin/content' page.
  if (variable_get('onlyone_new_menu_entry') && $root_path == 'admin/content') {
    $item = menu_get_item('onlyone/add');
    if ($item['access']) {
      $data['actions']['output'][] = array(
        '#theme' => 'menu_local_action',
        '#link' => $item,
        '#weight' => -1,
      );
    }
  }
}

/**
 * Implements hook_theme_registry_alter().
 */
function onlyone_theme_registry_alter(&$theme_registry) {

  // This is necessary due to:
  // https://www.drupal.org/project/drupal/issues/2965718 and will change once
  // this issue will be solved.
  if (variable_get('onlyone_new_menu_entry')) {
    $theme_registry['node_add_list']['file'] = 'onlyone.pages.inc';
    $theme_registry['node_add_list']['theme path'] = drupal_get_path('module', 'onlyone');
    $theme_registry['node_add_list']['function'] = 'onlyone_node_add_list';
  }
}

/**
 * Implements hook_preprocess_HOOK() for block content add list templates.
 */
function onlyone_preprocess_node_add_list(&$variables) {

  // Getting the configured content types to have only one node.
  $onlyone_content_types = variable_get('onlyone_node_types');

  // Getting the current path.
  $current_path = current_path();

  // Getting variable to know if we should show the configured content type
  // in a new page.
  $onlyone_new_menu_entry = variable_get('onlyone_new_menu_entry');

  // Creating the message variable.
  if ($current_path == 'onlyone/add') {
    $variables['message'] = t('You have not configured any content type yet, go to the <a href="@config-content-types">Only One page</a> to configure the content types.', array(
      '@config-content-types' => url('admin/config/content/onlyone'),
    ));
  }
  else {
    if ($onlyone_new_menu_entry) {
      $variables['message'] = t('All the content types are configured to have Only One node. Go to the <a href="@add-onlyone-content-type">Add content (Only One)</a> page to create or edit content.', array(
        '@add-onlyone-content-type' => url('onlyone/add'),
      ));
    }
    else {
      $variables['message'] = t('You have not created any content types yet. Go to the <a href="@create-content">Add content type</a> page to create content types.', array(
        '@create-content' => url('admin/structure/types/add'),
      ));
    }
  }

  // Loading the helper functions file.
  module_load_include('inc', 'onlyone', 'onlyone.helpers');

  // Changing the title.
  foreach ($variables['content'] as $key => $element) {

    // Getting the content type name.
    $content_type = substr($element['href'], 9);

    // Checking if the content type is configured.
    if (in_array($content_type, $onlyone_content_types)) {

      // We need to modify the links?
      if (!($onlyone_new_menu_entry xor $current_path == 'onlyone/add')) {

        // Checking if exists nodes created for the content type.
        if (_onlyone_exists_nodes_content_type($content_type)) {

          // Getting the content type name.
          $content_type_name = $variables['content'][$key]['title'];

          // Assigning the new name.
          $variables['content'][$key]['title'] = t('@content_type_name (Edit)', array(
            '@content_type_name' => $content_type_name,
          ));
        }
        $original_description = empty($variables['content'][$key]['description']) ? '' : rtrim($variables['content'][$key]['description'], '.') . '.';
        $variables['content'][$key]['description'] = t('!description <strong>Only a single node can be created and edited</strong>.', array(
          '!description' => $original_description,
        ));
      }
      else {

        // We need to delete the links.
        unset($variables['content'][$key]);
      }
    }
  }
}

/**
 * Implements hook_form_BASE_FORM_ID_alter().
 */
function onlyone_form_node_form_alter(&$form, &$form_state, $form_id) {

  // Getting the configured content types to have only one node.
  $onlyone_content_types = variable_get('onlyone_node_types');

  // Getting the name of the node type.
  $content_type = $form['type']['#value'];

  // Getting the node.
  $node = $form_state['node'];

  // Verifying if the new node should by onlyone and if we are trying to create
  // a new node.
  if (isset($onlyone_content_types) && in_array($content_type, $onlyone_content_types, TRUE) && (!isset($node->nid) || isset($node->is_new))) {

    // Loading the helper functions file.
    module_load_include('inc', 'onlyone', 'onlyone.helpers');

    // If we have one node, then redirect to the edit page.
    $nid = _onlyone_exists_nodes_content_type($content_type);
    if ($nid) {
      drupal_goto('node/' . $nid . '/edit');
    }
  }
}

/**
 * Implements hook_permission().
 */
function onlyone_permission() {
  return array(
    'administer onlyone' => array(
      'title' => t('Administer Only One'),
      'description' => t('Allow access to configure the module settings.'),
    ),
  );
}

/**
 * Implements hook_node_type_delete().
 */
function onlyone_node_type_delete($info) {

  // Getting the content type machine name.
  $content_type = $info->type;

  // Loading the helper functions file.
  module_load_include('inc', 'onlyone', 'onlyone.helpers');

  // Deleting the value from the config.
  _onlyone_delete_content_type_config($content_type);
}

/**
 * Implements hook_node_insert().
 */
function onlyone_node_insert($node) {

  // Loading the helper functions file.
  module_load_include('inc', 'onlyone', 'onlyone.helpers');

  // Rebuild the menu if needed.
  _onlyone_rebuild_menu($node->type);
}

/**
 * Implements hook_node_delete().
 */
function onlyone_node_delete($node) {

  // Loading the helper functions file.
  module_load_include('inc', 'onlyone', 'onlyone.helpers');

  // As there are not hooks to be fired once a node is deleted from the database
  // a trick similar to the https://www.drupal.org/project/hook_post_action
  // module needs to be implement, similar to the answer described in
  // https://stackoverflow.com/a/46038871/3653989 .
  // Invoking the callback function AFTER the node is deleted.
  drupal_register_shutdown_function('_onlyone_rebuild_menu', $node);
}

/**
 * Implements hook_node_validate().
 */
function onlyone_node_validate($node, $form, &$form_state) {

  // Getting the configured content types.
  $onlyone_content_types = variable_get('onlyone_node_types');

  // If the content type is configured and the language is locked we need to
  // check if exits a node created in the node language. See:
  // https://www.drupal.org/project/onlyone/issues/2962186
  // https://www.drupal.org/project/onlyone/issues/2969293 .
  if (in_array($node->type, $onlyone_content_types)) {

    // Loading the helper functions file.
    module_load_include('inc', 'onlyone', 'onlyone.helpers');

    // If we have a node in the current language we should not insert a new
    // one.
    $nid = _onlyone_exists_nodes_content_type($node->type, $node->language);

    // If the existing node have the same id that the node that is being saved
    // then is the same node that is being updated.
    if ($nid && $nid != $node->nid) {
      $existing_node = node_load($nid);
      $values = array(
        '%content_type' => $node->type,
        '@href' => url(drupal_get_path_alias('node/' . $existing_node->nid)),
        '!title' => $existing_node->title,
        '%language' => t('Language neutral'),
      );

      // Setting the error in the language field.
      form_set_error('language', t("The content type %content_type is configured to have Only One node per language but the node <a href='@href'>!title</a> exists for the %language language.", $values));
    }
  }
}

Functions

Name	Description
onlyone_admin_paths	Implements hook_admin_paths().
onlyone_form_node_form_alter	Implements hook_form_BASE_FORM_ID_alter().
onlyone_help	Implements hook_help().
onlyone_menu	Implements hook_menu().
onlyone_menu_link_alter	Implements hook_menu_link_alter().
onlyone_menu_local_tasks_alter	Implements hook_menu_local_tasks_alter().
onlyone_node_delete	Implements hook_node_delete().
onlyone_node_insert	Implements hook_node_insert().
onlyone_node_type_delete	Implements hook_node_type_delete().
onlyone_node_validate	Implements hook_node_validate().
onlyone_permission	Implements hook_permission().
onlyone_preprocess_node_add_list	Implements hook_preprocess_HOOK() for block content add list templates.
onlyone_theme_registry_alter	Implements hook_theme_registry_alter().

Constants

Name	Description
ONLYONE_FORMAT_FINAL_ADMIN
ONLYONE_FORMAT_FINAL_DRUSH
ONLYONE_FORMAT_INITIAL_ADMIN
ONLYONE_FORMAT_INITIAL_DRUSH	@file Allows to define if a content type must have more than one node in the site.