UserOnlineBlock.php

<?php

/**
 * @file
 * Contains \Drupal\user\Plugin\Block\UserOnlineBlock.
 */
namespace Drupal\user\Plugin\Block;

use Drupal\block\BlockBase;
use Drupal\Component\Annotation\Plugin;
use Drupal\Core\Annotation\Translation;

/**
 * Provides a "Who's online" block.
 *
 * @todo Move this block to the Statistics module and remove its dependency on
 *   {users}.access.
 *
 * @Plugin(
 *   id = "user_online_block",
 *   admin_label = @Translation("Who's online"),
 *   module = "user"
 * )
 */
class UserOnlineBlock extends BlockBase {

  /**
   * Overrides \Drupal\block\BlockBase::settings().
   */
  public function settings() {
    return array(
      'properties' => array(
        'administrative' => TRUE,
      ),
      'seconds_online' => 900,
      'max_list_count' => 10,
    );
  }

  /**
   * Overrides \Drupal\block\BlockBase::access().
   */
  public function access() {
    return user_access('access content');
  }

  /**
   * Overrides \Drupal\block\BlockBase::blockForm().
   */
  public function blockForm($form, &$form_state) {
    $period = drupal_map_assoc(array(
      30,
      60,
      120,
      180,
      300,
      600,
      900,
      1800,
      2700,
      3600,
      5400,
      7200,
      10800,
      21600,
      43200,
      86400,
    ), 'format_interval');
    $form['user_block_seconds_online'] = array(
      '#type' => 'select',
      '#title' => t('User activity'),
      '#default_value' => $this->configuration['seconds_online'],
      '#options' => $period,
      '#description' => t('A user is considered online for this long after they have last viewed a page.'),
    );
    $form['user_block_max_list_count'] = array(
      '#type' => 'select',
      '#title' => t('User list length'),
      '#default_value' => $this->configuration['max_list_count'],
      '#options' => drupal_map_assoc(array(
        0,
        5,
        10,
        15,
        20,
        25,
        30,
        40,
        50,
        75,
        100,
      )),
      '#description' => t('Maximum number of currently online users to display.'),
    );
    return $form;
  }

  /**
   * Overrides \Drupal\block\BlockBase::blockSubmit().
   */
  public function blockSubmit($form, &$form_state) {
    $this->configuration['seconds_online'] = $form_state['values']['user_block_seconds_online'];
    $this->configuration['max_list_count'] = $form_state['values']['user_block_max_list_count'];
  }

  /**
   * {@inheritdoc}
   */
  public function build() {

    // Count users active within the defined period.
    $interval = REQUEST_TIME - $this->configuration['seconds_online'];

    // Perform database queries to gather online user lists.
    $authenticated_count = db_query("SELECT COUNT(uid) FROM {users} WHERE access >= :timestamp", array(
      ':timestamp' => $interval,
    ))
      ->fetchField();
    $build = array(
      '#theme' => 'item_list__user__online',
      '#prefix' => '<p>' . format_plural($authenticated_count, 'There is currently 1 user online.', 'There are currently @count users online.') . '</p>',
    );

    // Display a list of currently online users.
    $max_users = $this->configuration['max_list_count'];
    if ($authenticated_count && $max_users) {
      $uids = db_query_range('SELECT uid FROM {users} WHERE access >= :interval AND uid > 0 ORDER BY access DESC', 0, $max_users, array(
        ':interval' => $interval,
      ))
        ->fetchCol();
      foreach (user_load_multiple($uids) as $account) {
        $build['#items'][] = theme('username', array(
          'account' => $account,
        ));
      }
    }
    return $build;
  }

}