Club Drupal

<?php

/**

 * @file

 * Enables users to authenticate via a Central Authentication Service (CAS)

 * Cas will currently work if the auto registration is turned on and will

 * create user accounts automatically.

 */

define('CAS_NO_LINK', 0);

define('CAS_ADD_LINK', 1);

define('CAS_MAKE_DEFAULT', 2);

define('CAS_REDIRECT', 3);

define('CAS_LOGIN_INVITE_DEFAULT', 'Log in using CAS');

define('CAS_LOGIN_DRUPAL_INVITE_DEFAULT', 'Cancel CAS login');

define('CAS_LOGIN_REDIR_MESSAGE', 'You will be redirected to the secure CAS login page.');

define('CAS_EXCLUDE', 'services/*');

// Frequency of CAS Gateway checking.

define('CAS_CHECK_NEVER', -2);

define('CAS_CHECK_ONCE', -1);

define('CAS_CHECK_ALWAYS', 0);

/**

 * Implements hook_init().

 *

 * Traps a page load to see if authentication is required.

 */

function cas_init() {

  global $user;

  if (module_exists('cas_test') && arg(0) == 'cas_test') {

    // We are destined for a page handled by the cas_test module, so do not

    // do any processing here. Necessary for CAS gateway tests.

    return;

  }

  elseif (defined('MAINTENANCE_MODE') && MAINTENANCE_MODE === 'install') {

    // Do nothing on profile install.

    return;

  }

  // Process a single-sign out request.

  _cas_single_sign_out_check();

  // If a user is not logged in, consider using CAS authentication.

  if (!$user->uid) {

    $force_authentication = _cas_force_login();

    $check_authentication = _cas_allow_check_for_login();

    $request_type = $_SERVER['REQUEST_METHOD'];

    $perform_login_check = $force_authentication || ($check_authentication && ($request_type == 'GET'));

    if ($perform_login_check) {

      cas_login_check($force_authentication);

    }

  }

}

/**

 * Checks to see if the user needs to be logged in.

 *

 * @param $force_authentication

 *   If TRUE, require that the user be authenticated with the CAS server

 *   before proceeding. Otherwise, check with the CAS server to see if the

 *   user is already logged in.

 */

function cas_login_check($force_authentication = TRUE) {

  global $user;

  if ($user->uid) {

    //Don't Login  because we already are

    return;

  }

  if (!cas_phpcas_load()) {

    // No need to print a message, as the user will already see the failed

    // include_once calls.

    return;

  }

  // Start a drupal session

  drupal_session_start();

  _cas_single_sign_out_save_ticket();  // We use this later for CAS 3 logoutRequests

  // Initialize phpCAS if possible, otherwise just back out.

  if (cas_phpcas_init() === FALSE) {

    return;

  }

  // We're going to try phpCAS auth test

  if ($force_authentication) {

    try {

      phpCAS::forceAuthentication();

    }

    catch (CAS_AuthenticationException $e) {

      drupal_set_message(t('Error authenticating with CAS. Please try again or contact your website administrator if the problem persists.'), 'error');

      watchdog_exception('cas', $e);

      // We have to redirect the user somewhere else because the CAS exception

      // will have written error details directly to stdout, and we don't want

      // to show anything like that to the user.

      // This bring users to the homepage or to the page set in destination

      // param.

      drupal_goto('');

    }

  }

  else {

    $logged_in = phpCAS::checkAuthentication();

    // We're done cause we're not logged in.

    if (!$logged_in) {

      return;

    }

  }

  // Build the cas_user object and allow modules to alter it.

  $cas_user = array(

    'name' => phpCAS::getUser(),

    'login' => TRUE,

    'register' => variable_get('cas_user_register', TRUE),

    'attributes' => cas_phpcas_attributes(),

  );

  drupal_alter('cas_user', $cas_user);

  // Bail out if a module denied login access for this user or unset the user

  // name.

  if (empty($cas_user['login']) || empty($cas_user['name'])) {

    // Only set a warning if we forced login.

    if ($force_authentication) {

      drupal_set_message(t('The user account %name is not available on this site.', array('%name' => $cas_user['name'])), 'error');

    }

    return;

  }

  // Proceed with the login process, using the altered CAS username.

  $cas_name = $cas_user['name'];

  // blocked user check

  $blocked = FALSE;

  if (_cas_external_user_is_blocked($cas_name)) {

      $blocked = 'The username %cas_name has been blocked.';

  }

  // @todo The D7 equivalent here must have been renamed.

  // elseif (drupal_is_denied('user', $cas_name)) {

  //   // denied by access controls

  //   return 'The name %cas_name is a reserved username.';

  // }

  if ($blocked) {

    // Only display error messages only if the user intended to log in.

    if ($force_authentication) {

      watchdog('cas', $blocked, array('%cas_name' => $cas_name), WATCHDOG_WARNING);

      drupal_set_message(t($blocked, array('%cas_name' => $cas_name)), 'error');

    }

    return;

  }

  $account = cas_user_load_by_name($cas_name);

  // Automatic user registration.

  if (!$account && $cas_user['register']) {

    // No account could be found and auto registration is enabled, so attempt

    // to register a new user.

    $account = cas_user_register($cas_name);

    if (!$account) {

      // The account could not be created, set a message.

      if ($force_authentication) {

        drupal_set_message(t('A new account could not be created for %cas_name. The username is already in use on this site.', array('%cas_name' => $cas_name)), 'error');

      }

      return;

    }

  }

  // final check to make sure we have a good user

  if ($account && $account->uid > 0) {

    // Save the altered CAS name for future use.

    $_SESSION['cas_name'] = $cas_name;

    $cas_first_login = !$account->login;

    // Save single sign out information

    if (!empty($_SESSION['cas_ticket'])) {

      _cas_single_sign_out_save_token($account);

    }

    // Populate $edit with some basic properties.

    $edit['cas_user'] = $cas_user;

    $edit['roles'] = $account->roles + cas_roles();

    if (module_exists('persistent_login') && !empty($_SESSION['cas_remember'])) {

      $edit['values']['persistent_login'] = 1;

    }

    // Allow other modules to make their own custom changes.

    cas_user_module_invoke('presave', $edit, $account);

    // Save the user account and log the user in.

    $user = user_save($account, $edit);

    user_login_finalize($edit);

    drupal_set_message(t(variable_get('cas_login_message', 'Logged in via CAS as %cas_username.'), array('%cas_username' => format_username($user))));

    if (!empty($edit['persistent_login'])) {

      drupal_set_message(t('You will remain logged in on this computer even after you close your browser.'));

    }

    _cas_redirect_after_login($cas_first_login);

  }

  else {

    $user = drupal_anonymous_user();

    unset($_SESSION['phpCAS']);

    // Only display error messages only if the user intended to log in.

    if ($force_authentication) {

      drupal_set_message(t('No account found for %cas_name.', array('%cas_name' => $cas_name)), 'error');

    }

  }

}

/**

 * Loads the phpCAS library.

 *

 * @param $path

 *   Attempt to load phpCAS using this path. If omitted, phpCAS will be loaded

 *   using Libraries API or the configured value.

 *

 * @return

 *   The phpCAS version if the phpCAS was successfully loaded, FALSE otherwise.

 */

function cas_phpcas_load($path = NULL) {

  if (!isset($path)) {

    if (module_exists('libraries')) {

      $path = libraries_get_path('CAS');

    }

    else {

      $path = variable_get('cas_library_dir', 'CAS');

    }

  }

  // Build the name of the file to load.

  if ($path != '') {

    $path = rtrim($path, '/') . '/';

  }

  $filename = $path . 'CAS.php';

  include_once($filename);

  if (!defined('PHPCAS_VERSION') || !class_exists('phpCAS')) {

    // The file could not be loaded successfully.

    return FALSE;

  }

  return PHPCAS_VERSION;

}

/**

 * Initialize phpCAS.

 *

 * Will load phpCAS if necessary.

 */

function cas_phpcas_init() {

  if (!defined('PHPCAS_VERSION') || !class_exists('phpCAS')) {

    cas_phpcas_load();

  }

  $initialized = &drupal_static(__FUNCTION__, FALSE);

  if ($initialized) {

    // phpCAS cannot be initialized twice. If you need to force this function

    // to run again, call drupal_static_reset('cas_phpcas_init') first.

    return;

  }

  $initialized = TRUE;

  // Variable set

  $server_version    = (string)variable_get('cas_version', '3.0');

  $server_cas_server = (string)variable_get('cas_server', '');

  $server_port       = (int)variable_get('cas_port', '443');

  $server_uri        = (string)variable_get('cas_uri', '');

  $cas_cert          = (string)variable_get('cas_cert', '');

  $debug_file        = (string)variable_get('cas_debugfile', '');

  // Back out if there's no configured CAS server hostname. This is the

  // minimum required configuration to initialize phpCAS.

  if (empty($server_cas_server)) {

    watchdog('cas', 'Unable to initialize phpCAS because no CAS server hostname has been configured.', array(), WATCHDOG_ERROR);

    return FALSE;

  }

  if ($debug_file != '') {

    phpCAS::setDebug($debug_file);

  }

  $start_session = (boolean)FALSE;

  if (variable_get('cas_proxy', 0)) {

    phpCAS::proxy($server_version, $server_cas_server, $server_port, $server_uri, $start_session);

    $cas_pgt_storage_path = variable_get('cas_pgtpath', '');

    if ($cas_pgt_storage_path != '') {

      if (version_compare(PHPCAS_VERSION, '1.3', '>=')) {

        phpCAS::setPGTStorageFile($cas_pgt_storage_path);

      }

      else {

        $cas_pgt_format = variable_get('cas_pgtformat', 'plain');

        phpCAS::setPGTStorageFile($cas_pgt_format, $cas_pgt_storage_path);

      }

    }

  }

  else {

    phpCAS::client($server_version, $server_cas_server, $server_port, $server_uri, $start_session);

  }

  //Add CAS proxy lists allowed

  $proxy_list = variable_get('cas_proxy_list', '');

  if ($proxy_list) {

    $proxy_list = explode("\n", $proxy_list);

    phpCAS::allowProxyChain(new CAS_ProxyChain($proxy_list));

  }

  // force CAS authentication

  if ($cas_cert = variable_get('cas_cert', '')) {

    phpCAS::setCasServerCACert($cas_cert);

  }

  else {

    phpCAS::setNoCasServerValidation();

  }

  phpCAS::setFixedServiceURL(url(current_path(), array('query' => drupal_get_query_parameters(), 'absolute' => TRUE)));

  phpCAS::setCacheTimesForAuthRecheck((int) variable_get('cas_check_frequency', CAS_CHECK_NEVER));

  // Allow other modules to call phpCAS routines. We do not call

  // drupal_alter() since there are no parameters to pass.

  module_invoke_all('cas_phpcas_alter');

}

/**

 * Implements hook_permission().

 */

function cas_permission() {

  return array(

    'administer cas' => array(

      'title' => t('Administer CAS'),

      'description' => t('Configure CAS server, default CAS user roles, login/logout redirection, and other settings.'),

      'restrict access' => TRUE,

    )

  );

}

/**

 * Implements hook_help().

 */

function cas_help($section) {

  switch ($section) {

    case 'admin/help#cas':

      return t("Allows users to authenticate via a Central Authentication Service.");

  }

}

/**

 * Implements hook_menu().

 */

function cas_menu() {

  global $user;

  $items = array();

  //cas_login_check();

  $items['admin/config/people/cas'] = array(

    'title' => 'CAS settings',

    'description' => 'Configure central authentication services',

    'page callback' => 'drupal_get_form',

    'page arguments' => array('cas_admin_settings'),

    'access arguments' => array('administer cas'),

    'type' => MENU_NORMAL_ITEM,

    'file' => 'cas.admin.inc',

  );

  $items['admin/config/people/cas/settings'] = array(

    'title' => 'CAS',

    'type' => MENU_DEFAULT_LOCAL_TASK,

    'weight' => -10,

  );

  $items['admin/people/cas/create'] = array(

    'title' => 'Add CAS user(s)',

    'page callback' => 'drupal_get_form',

    'page arguments' => array('cas_add_user_form'),

    'access arguments' => array('administer users'),

    'type' => MENU_LOCAL_ACTION,

    'file' => 'cas.user.inc',

    'tab_parent' => 'admin/people',

    'weight' => 1,

  );

  $items['user/%user/cas'] = array(

    'title' => 'CAS',

    'page callback' => 'cas_user_identities',

    'page arguments' => array(1),

    'access arguments' => array('administer users'),

    'type' => MENU_LOCAL_TASK,

    'file' => 'cas.pages.inc',

    'tab_parent' => 'user/%/edit',

    'weight' => 1,

  );

  $items['user/%user/cas/delete'] = array(

    'title' => 'Delete CAS username',

    'page callback' => 'drupal_get_form',

    'page arguments' => array('cas_user_delete_form', 1),

    'access arguments' => array('administer users'),

    'file' => 'cas.pages.inc',

  );

  $items['cas'] = array(

    'path' => 'cas',

    'title' => 'CAS Login',

    'page callback' => 'cas_login_page',

    'access callback' => 'user_is_anonymous',

    'type' => MENU_SUGGESTED_ITEM,

  );

  $items['caslogout'] = array(

    'title' => 'CAS Logout',

    'page callback' => 'cas_logout',

    'access callback' => 'cas_user_is_logged_in',

    'type' => MENU_SUGGESTED_ITEM,

  );

  return $items;

}

/**

 * Implements hook_cron().

 */

function cas_cron() {

  // Clear old single logout session mapping data.

  $max_days = (int) variable_get('cas_single_logout_session_lifetime', 25);

  $seconds_in_day = 86400;

  $seconds = $max_days * $seconds_in_day;

  if ($seconds > 0) {

    db_delete('cas_login_data')

      ->condition('created', time() - $seconds, '<=')

      ->execute();

  }

}

function cas_user_is_logged_in() {

  return user_is_logged_in() || !empty($_SESSION['phpCAS']['user']);

}

/**

 * Implements hook_menu_site_status_alter().

 */

function cas_menu_site_status_alter(&$menu_site_status, $path) {

  if (user_is_logged_in() && strtolower($path) == 'cas') {

    // If user is logged in, redirect to '<front>' instead of giving 403.

    drupal_goto('');

  }

}

/**

 * Implements hook_menu_link_alter().

 *

 * Flag this link as needing alter at display time.

 * @see cas_translated_menu_link_alter()

 */

function cas_menu_link_alter(&$item) {

  $link_path = strtolower($item['link_path']);

  if ($link_path == 'cas' || $link_path == 'caslogout') {

    $item['options']['alter'] = TRUE;

  }

}

/**

 * Implements hook_translated_menu_item_alter().

 *

 * Append dynamic query 'destination' to CAS menu links.

 */

function cas_translated_menu_link_alter(&$item) {

  $href = strtolower($item['href']);

  $append_destination = $href == 'cas' || ($href == 'caslogout' && !variable_get('cas_logout_destination', ''));

  if ($append_destination) {

    // Don't overwrite existing query params that may exist in the menu link.

    if (isset($item['localized_options']['query'])) {

      $menu_link_query_params = array_merge(drupal_get_destination(), $item['localized_options']['query']);

    }

    else {

      $menu_link_query_params = drupal_get_destination();

    }

    $item['localized_options']['query'] = $menu_link_query_params;

  }

}

/**

 * Implements hook_user_operations().

 */

function cas_user_operations($form = array(), $form_state = array()) {

  $operations['cas_create'] = array(

    'label' => t('Create CAS username'),

    'callback' => 'cas_user_operations_create_username',

  );

  $operations['cas_remove'] = array(

    'label' => t('Remove CAS usernames'),

    'callback' => 'cas_user_operations_remove_usernames',

  );

  return $operations;

}

/**

 * Callback function to assign a CAS username to the account.

 *

 * @param $uids

 *   An array of user ids. For each account, a CAS username is created with

 *   the same name as the Drupal username.

 *

 * @see cas_user_operations()

 */

function cas_user_operations_create_username($uids) {

  $accounts = user_load_multiple($uids);

  foreach ($accounts as $account) {

    $count = db_select('cas_user', 'c')

      ->condition('cas_name', $account->name)

      ->condition('uid', $account->uid, '<>')

      ->countQuery()->execute()->fetchfield();

    if ($count) {

      drupal_set_message(t('CAS username %username already in use.', array('%username' => $account->name)), 'error');

      continue;

    }

    db_merge('cas_user')

      ->key(array('cas_name' => $account->name))

      ->fields(array('uid' => $account->uid))

      ->execute();

  }

}

/**

 * Callback function to remove CAS usernames from the account.

 *

 * @param $uids

 *   An array of user ids. For each account, all CAS usernames are removed.

 *

 * @see cas_user_operations()

 */

function cas_user_operations_remove_usernames($uids) {

  db_delete('cas_user')

    ->condition('uid', $uids, 'IN')

    ->execute();

}

/**

 * Implements hook_admin_paths().

 */

function cas_admin_paths() {

  $paths = array(

    'user/*/cas' => TRUE,

    'user/*/cas/delete/*' => TRUE,

  );

  return $paths;

}

/**

 * Implements hook_user_load().

 *

 * Adds an associative array 'cas_names' to each user. The array keys are

 * unique authentication mapping ids, with CAS usernames as the values.

 */

function cas_user_load($users) {

  foreach (array_keys($users) as $uid) {

    $users[$uid]->cas_names = array();

  }

  $result = db_query('SELECT aid, uid, cas_name FROM {cas_user} WHERE uid IN (:uids)', array(':uids' => array_keys($users)));

  foreach ($result as $record) {

    $users[$record->uid]->cas_names[$record->aid] = $record->cas_name;

  }

  foreach (array_keys($users) as $uid) {

    $users[$uid]->cas_name = reset($users[$uid]->cas_names);

  }

}

/**

 * Implements hook_user_insert().

 *

 * When a user is created, record their CAS username if provided.

 */

function cas_user_insert(&$edit, $account, $category) {

  if (!empty($edit['cas_name'])) {

    db_insert('cas_user')

      ->fields(array(

        'cas_name' => $edit['cas_name'],

        'uid' => $account->uid,

      ))

      ->execute();

  }

  // Update $account to reflect changes.

  $users = array($account->uid => $account);

  cas_user_load($users);

}

/**

 * Implements hook_user_update().

 *

 * When a user is updated, change their CAS username if provided.

 */

function cas_user_update(&$edit, $account, $category) {

  if (!array_key_exists('cas_name', $edit)) {

    // If the cas_name key is not provided, there is nothing to do.

    return;

  }

  $cas_name = $edit['cas_name'];

  // See if the user currently has any CAS names.

  reset($account->cas_names);

  if ($aid = key($account->cas_names)) {

    // The user already has CAS username(s) set.

    if (empty($cas_name)) {

      // Remove a CAS username.

      db_delete('cas_user')

        ->condition('uid', $account->uid)

        ->condition('aid', $aid)

        ->execute();

    }

    else {

      // Change a CAS username.

      if ($cas_name != $account->cas_names[$aid]) {

        db_update('cas_user')

          ->fields(array('cas_name' => $cas_name))

          ->condition('uid', $account->uid)

          ->condition('aid', $aid)

          ->execute();

      }

    }

  }

  else {

    // No current CAS usernames.

    if (!empty($cas_name)) {

      // Add a CAS username.

      db_insert('cas_user')

        ->fields(array(

          'uid' => $account->uid,

          'cas_name' => $cas_name,

        ))

        ->execute();

    }

  }

  // Update $account to reflect changes.

  $users = array($account->uid => $account);

  cas_user_load($users);

}

/**

 * Implement hook_user_delete().

 *

 * When a CAS user is deleted, we need to clean up the entry in {cas_user}.

 */

function cas_user_delete($account) {

  db_delete('cas_user')

    ->condition('uid', $account->uid)

    ->execute();

}

/**

 * Fetch a user object by CAS name.

 *

 * @param $cas_name

 *   The name of the CAS user.

 * @param $alter

 *   If TRUE, run the CAS username through hook_cas_user_alter() before

 *   loading the account.

 * @param $reset

 *   TRUE to reset the internal cache and load from the database; FALSE

 *   (default) to load from the internal cache, if set.

 *

 * @return

 *   A fully-loaded $user object upon successful user load or FALSE if user

 *   cannot be loaded.

 */

function cas_user_load_by_name($cas_name, $alter = FALSE, $reset = FALSE) {

  if ($alter) {

    $cas_user = array(

      'name' => $cas_name,

      'login' => TRUE,

      'register' => FALSE,

    );

    drupal_alter('cas_user', $cas_user);

    $cas_name = $cas_user['name'];

  }

  $uid = db_select('cas_user')->fields('cas_user', array('uid'))->condition('cas_name', db_like($cas_name), 'LIKE')->range(0, 1)->execute()->fetchField();

  if ($uid) {

    return user_load($uid, $reset);

  }

  return FALSE;

}

/**

 * This is the page callback for the /cas page, which is used only to

 * trigger a forced CAS authentication.

 *

 * In almost all cases, the user will have been redirected before even

 * hitting this page (see hook_init implementation). But as a stop gap

 * just redirect to the homepage.

 */

function cas_login_page() {

  drupal_goto('');

}

/**

 * Logs a user out of Drupal and then out of CAS.

 *

 * This function does not return, but instead immediately redirects the user

 * to the CAS server to complete the CAS logout process.

 *

 * Other modules intending to call this from their implementation of

 * hook_user_logout() will need to pass $invoke_hook = FALSE to avoid an

 * infinite recursion. WARNING: since this function does not return, any

 * later implementations of hook_user_logout() will not run. You may wish to

 * adjust the hook execution order using hook_module_implements_alter().

 *

 * @param $invoke_hook

 *   If TRUE, invoke hook_user_logout() and save a watchdog message indicating

 *   that the user has logged out.

 */

function cas_logout($invoke_hook = TRUE) {

  global $user;

  // Build the logout URL.

  cas_phpcas_init();

  if (isset($_GET['destination']) && !url_is_external($_GET['destination'])) {

    // Add destination override so that a destination can be specified on the

    // logout link, e.g., caslogout?destination=http://foo.bar.com/foobar. We do

    // not allow absolute URLs to be passed via $_GET, as this can be an attack

    // vector.

    $destination = $_GET['destination'];

  }

  else {

    $destination = variable_get('cas_logout_destination', '');

  }

  //Make it an absolute url.  This will also convert <front> to the front page.

  if ($destination) {

    $destination_url = url($destination, array('absolute' => TRUE));

    $options = array(

      'service' => $destination_url,

      'url' => $destination_url,

    );

  }

  else {

    $options = array();

  }

  // Mimic user_logout().

  if ($invoke_hook) {

    watchdog('user', 'Session closed for %name.', array('%name' => format_username($user)));

    module_invoke_all('user_logout', $user);

  }

  // phpCAS automatically calls session_destroy().

  phpCAS::logout($options);

}

/**

 * Implements hook_block_info().

 */

function cas_block_info() {

  $blocks['login']['info'] = t('CAS login');

  // Not worth caching.

  $blocks['login']['cache'] = DRUPAL_NO_CACHE;

  return $blocks;

}

/**

 * Implements hook_block_view().

 */

function cas_block_view($delta = '') {

  global $user;

  $block = array();

  switch ($delta) {

    case 'login':

      // For usability's sake, avoid showing two login forms on one page.

      if (!$user->uid && !(arg(0) == 'user' && !is_numeric(arg(1)))) {

        $block['subject'] = t('User login');

        $block['content'] = drupal_get_form('cas_login_block');

      }

      return $block;

  }

}

/**

 * Login form for the CAS login block.

 */

function cas_login_block($form) {

  $form['#action'] = url('cas', array('query' => drupal_get_destination()));

  $form['#id'] = 'cas-login-form';

  $form['cas_login_redirection_message'] = array(

    '#type' => 'item',

    '#markup' => t(variable_get('cas_login_redir_message', CAS_LOGIN_REDIR_MESSAGE)),

    '#weight' => -1,

  );

  $form['actions'] = array('#type' => 'actions');

  $form['actions']['submit'] = array(

    '#type' => 'submit',

    '#value' => t(variable_get('cas_login_invite', CAS_LOGIN_INVITE_DEFAULT)),

  );

  return $form;

}

/**

 * Determine if we should automatically check if the user is authenticated.

 *

 * This implements part of the CAS gateway feature.

 * @see phpCAS::checkAuthentication()

 *

 * @return

 *   TRUE if we should query the CAS server to see if the user is already

 *   authenticated, FALSE otherwise.

 */

function _cas_allow_check_for_login() {

  // Do not process in maintenance mode.

  if (variable_get('maintenance_mode', 0)) {

    return FALSE;

  }

  if (variable_get('cas_check_frequency', CAS_CHECK_NEVER) == CAS_CHECK_NEVER) {

    // The user has disabled the feature.

    return FALSE;

  }

  // Check to see if we've got a search bot.

  if (isset($_SERVER['HTTP_USER_AGENT'])) {

    $crawlers = array(

      'Google',

      'msnbot',

      'Rambler',

      'Yahoo',

      'AbachoBOT',

      'accoona',

      'AcoiRobot',

      'ASPSeek',

      'CrocCrawler',

      'Dumbot',

      'FAST-WebCrawler',

      'GeonaBot',

      'Gigabot',

      'Lycos',

      'MSRBOT',

      'Scooter',

      'AltaVista',

      'IDBot',

      'eStyle',

      'Scrubby',

      'gsa-crawler',

      );

    // Return on the first find.

    foreach ($crawlers as $c) {

      if (stripos($_SERVER['HTTP_USER_AGENT'], $c) !== FALSE) {

        return FALSE;

      }

    }

  }

  // Do not force login for XMLRPC, Cron, or Drush.

  if (stristr($_SERVER['SCRIPT_FILENAME'], 'xmlrpc.php')) {

    return FALSE;

  }

  if (stristr($_SERVER['SCRIPT_FILENAME'], 'cron.php')) {

    return FALSE;

  }

  if (stristr($_SERVER['SCRIPT_FILENAME'], 'drush')) {

    return FALSE;

  }

  if (!empty($_SERVER['argv'][0]) && stristr($_SERVER['argv'][0], 'drush')) {

    return FALSE;

  }

  // Test against exclude pages.

  if ($pages = variable_get('cas_exclude', CAS_EXCLUDE)) {

    $path = drupal_get_path_alias($_GET['q']);

    if (drupal_match_path($path, $pages)) {

      return FALSE;

    }

  }

  return TRUE;

}

/**

 * Determine if we should require the user be authenticated.

 *

 * @return

 *   TRUE if we should require the user be authenticated, FALSE otherwise.

 */

function _cas_force_login() {

  // The 'cas' page is a shortcut to force authentication.

  if (strtolower(arg(0)) == 'cas') {

    return TRUE;

  }

  // Do not process in maintenance mode.

  if (variable_get('maintenance_mode', 0)) {

    return FALSE;

  }

  // Do not force login for XMLRPC, Cron, or Drush.

  if (stristr($_SERVER['SCRIPT_FILENAME'], 'xmlrpc.php')) {

    return FALSE;

  }

  if (stristr($_SERVER['SCRIPT_FILENAME'], 'cron.php')) {

    return FALSE;

  }

  if (function_exists('drush_verify_cli') && drush_verify_cli()) {

    return FALSE;

  }

  // Excluded page do not need login.

  if ($pages = variable_get('cas_exclude', CAS_EXCLUDE)) {

    $path = drupal_get_path_alias($_GET['q']);

    if (drupal_match_path($path, $pages)) {

      return FALSE;

    }

  }

  // Set the default behavior.

  $force_login = variable_get('cas_access', 0);

  // If we match the specified paths, reverse the behavior.

  if ($pages = variable_get('cas_pages', '')) {

    $path = drupal_get_path_alias($_GET['q']);

    if (drupal_match_path($path, $pages)) {

      $force_login = !$force_login;

    }

  }

  return $force_login;

}

/**

 * Implements hook_form_alter().

 *

 * Overrides specific from settings based on user policy.

 */

function cas_form_alter(&$form, &$form_state, $form_id) {

  // Special handling of the user login page when the CAS login form is set to

  // redirect.

  if ($form_id == 'user_login' && variable_get('cas_login_form', CAS_NO_LINK) == CAS_REDIRECT) {

    drupal_goto('cas');

  }

  switch ($form_id) {

    case 'user_login':

    case 'user_login_block':

      if (variable_get('cas_login_form', CAS_NO_LINK) != CAS_NO_LINK) {

        $form['#attached']['css'][] = drupal_get_path('module', 'cas') . '/cas.css';

        $form['#attached']['js'][] = drupal_get_path('module', 'cas') . '/cas.js';

        if (!empty($form_state['input']['cas_identifier'])) {

          $form['name']['#required'] = FALSE;

          $form['pass']['#required'] = FALSE;

          unset($form['#validate']);

          $form['#submit'] = array('cas_login_submit');

        }

        $items = array();

        $items[] = array(

          'data' => l(t(variable_get('cas_login_invite', CAS_LOGIN_INVITE_DEFAULT)), '#'),

          'class' => array('cas-link'),

        );

        $items[] = array(

          'data' => l(t(variable_get('cas_login_drupal_invite', CAS_LOGIN_DRUPAL_INVITE_DEFAULT)), '#'),

          'class' => array('uncas-link'),

        );

        $form['cas_links'] = array(

          '#theme' => 'item_list',

          '#items' => $items,

          '#attributes' => array('class' => array('cas-links')),

          '#weight' => 101,

        );

        $form['links']['#weight'] = 2;

        $form['cas_login_redirection_message'] = array(

          '#type' => 'item',

          '#markup' => t(variable_get('cas_login_redir_message', CAS_LOGIN_REDIR_MESSAGE)),

          '#weight' => -1,

        );

        $form['cas_identifier'] = array(

          '#type' => 'checkbox',

          '#title' => t(variable_get('cas_login_invite', CAS_LOGIN_INVITE_DEFAULT)),

          '#default_value' => variable_get('cas_login_form', CAS_NO_LINK) == CAS_MAKE_DEFAULT,

          '#weight' => -1,

          '#description' => t(variable_get('cas_login_redir_message', CAS_LOGIN_REDIR_MESSAGE)),

        );

        $form['cas.return_to'] = array('#type' => 'hidden', '#value' => user_login_destination());

      }

      break;

    case 'user_profile_form':

      $account = $form['#user'];

      if (user_access('administer users')) {

        // The user is an administrator, so add fields to allow changing the

        // CAS username(s) associated with the account.

        $cas_names = $account->cas_names;

        $aids = array_keys($cas_names);

        $element = array(

          '#type' => 'textfield',

          '#title' => t('CAS username'),

          '#default_value' => array_shift($cas_names),

          '#cas_user_aid' => array_shift($aids),

          '#description' => t('<a href="@url">Create, edit or delete</a> additional CAS usernames associated with this account.', array('@url' => url('user/' . $account->uid . '/cas'))),

          '#element_validate' => array('_cas_name_element_validate'),

          '#weight' => -9,

        );

        // See if any additional CAS usernames exist.

        if (!empty($cas_names)) {

          $element['#description'] .= ' <br />' . t('Other CAS usernames: %cas_names.', array('%cas_names' => implode(', ', $cas_names)));

        }

        $form['account']['cas_name'] = $element;

      }

      elseif (cas_is_external_user($account)) {

        // The user is not an administrator, so selectively remove the e-mail

        // and password fields.

        if (variable_get('cas_hide_email', 0)) {

          $form['account']['mail']['#access'] = FALSE;

        }

        if (variable_get('cas_hide_password', 0)) {

          $form['account']['pass']['#access'] = FALSE;

        }

      }

      if (cas_is_external_user($account) && variable_get('cas_hide_password', 0)) {

        // Also remove requirement to validate your current password before

        // changing your e-mail address.

        $form['account']['current_pass']['#access'] = FALSE;

        $form['account']['current_pass_required_values']['#access'] = FALSE;

        $form['account']['current_pass_required_values']['#value'] = array();

        $form['#validate'] = array_diff($form['#validate'], array('user_validate_current_pass'));

      }

      break;

    case 'user_pass':

      if (!user_access('administer users') && variable_get('cas_changePasswordURL', '') != '') {

        drupal_goto(variable_get('cas_changePasswordURL', ''));

      }

      break;

    case 'user_register_form':

      if (user_access('administer users')) {

        $form['account']['cas_name'] = array(

          '#type' => 'textfield',

          '#title' => t('CAS username'),

          '#default_value' => '',

          '#description' => t('If necessary, additional CAS usernames can be added after the account is created.'),

          '#element_validate' => array('_cas_name_element_validate'),

          '#weight' => -9,

        );

      }

      elseif (variable_get('cas_registerURL', '') != '') {

        drupal_goto(variable_get('cas_registerURL', ''));

      }

      break;

    case 'user_admin_account':

      // Insert the CAS username into the second column.

      _cas_array_insert($form['accounts']['#header'], 1, array(

        'cas' => array(

          'data' => 'CAS usernames',

        ),

      ));

      foreach ($form['accounts']['#options'] as $uid => &$row) {

        $cas_usernames = db_query('SELECT cas_name FROM {cas_user} WHERE uid = :uid', array(':uid' => $uid))->fetchCol();

        $row['cas'] = theme('item_list', array('items' => $cas_usernames));

      }

      break;

  }

}

/**

 * Form element 'cas_name' validator.

 *

 * If the element is displaying an existing {cas_user} entry, set

 * #cas_user_aid to the corresponding authmap id to avoid spurious

 * validation errors.

 */

function _cas_name_element_validate($element, &$form_state) {

  if (empty($element['#value'])) {

    // Nothing to validate if the name is empty.

    return;

  }

  $query = db_select('cas_user')

    ->fields('cas_user', array('uid'))

    ->condition('cas_name', $element['#value']);

  // If set, we ignore entries with a specified authmap id. This is used on

  // the user/%user/edit page to not throw validation errors when we do not

  // change the CAS username.

  if (isset($element['#cas_user_aid'])) {

    $query->condition('aid', $element['#cas_user_aid'], '<>');

  }

  $uid = $query->execute()->fetchField();

  if ($uid !== FALSE) {

    // Another user is using this CAS username.

    form_set_error('cas_name', t('The CAS username is <a href="@edit-user-url">already in use</a> on this site.', array('@edit-user-url' => url('user/' . $uid . '/edit'))));

  }

}

/**

 * Login form _validate hook

 */

function cas_login_submit(&$form, &$form_state) {

  if (!empty($form_state['values']['persistent_login'])) {

    $_SESSION['cas_remember'] = 1;

  }

  // Force redirection.

  unset($_GET['destination']);

  drupal_goto('cas', array('query' => $form_state['values']['cas.return_to']));

}

function _cas_single_sign_out_check() {

  if (isset($_POST["logoutRequest"])) {

    $cas_logout_request_xml_string = utf8_encode(urldecode($_POST["logoutRequest"]));

    $cas_logout_request_xml = new SimpleXMLElement($cas_logout_request_xml_string);

    if (is_object($cas_logout_request_xml)) {

      $namespaces = $cas_logout_request_xml->getNameSpaces();

      $xsearch = 'SessionIndex';

      if (isset($namespaces['samlp'])) {

        $cas_session_indexes = $cas_logout_request_xml->children($namespaces['samlp'])->SessionIndex;

      }

      else {

        $cas_session_indexes = $cas_logout_request_xml->xpath($xsearch);

      }

      if ($cas_session_indexes) {

        $cas_session_index = (string)$cas_session_indexes[0];

        // Log them out now.

        // first lets find out who we want to log off

        $hashed_ticket = hash('sha256', $cas_session_index);

        $record = db_query_range("SELECT cld.uid, u.name FROM {users} u JOIN {cas_login_data} cld ON u.uid = cld.uid WHERE cld.cas_session_id = :ticket", 0, 1, array(':ticket' => $hashed_ticket))->fetchObject();

        if ($record) {

          watchdog('user', 'Session closed for %name by CAS logout request.', array('%name' => $record->name));

          //remove all entry for user id in cas_login_data

          db_delete('cas_login_data')

            ->condition('uid', $record->uid)

            ->execute();

          // remove their session

          db_delete('sessions')

            ->condition('uid', $record->uid)

            ->execute();

        }

      }

    }

    // This request is done, so just exit.

    exit();

  }

}

/**

 * Return the current CAS username.

 */

function cas_current_user() {

  return isset($_SESSION['cas_name']) ? $_SESSION['cas_name'] : FALSE;

}

/**

 * Determine whether the specified user is an "external" CAS user.

 * When settings are set to use drupal as the user repository, then this

 * function will always return true.

 *

 * @param $account

 *   The user object for the user to query. If omitted, the current user is

 *   used.

 *

 * @return

 *   TRUE if the user is logged in via CAS.

 */

function cas_is_external_user($account = NULL) {

  if (!isset($account)) {

    $account = $GLOBALS['user'];

  }

  return in_array(cas_current_user(), $account->cas_names);

}

function _cas_single_sign_out_save_token($user) {

  // Ok lets save the CAS service ticket to DB so

  // we can handle CAS logoutRequests when they come

  if ($user->uid && $user->uid > 0 && !empty($_SESSION['cas_ticket'])) {

    $hashed_ticket = hash('sha256', $_SESSION['cas_ticket']);

    db_merge('cas_login_data')

      ->key(array('cas_session_id' => $hashed_ticket))

      ->fields(array(

        'cas_session_id' => $hashed_ticket,

        'uid' => $user->uid,

        'created' => time(),

      ))

      ->execute();

    unset($_SESSION['cas_ticket']);

  }

}

/**

 * Make sure that we persist ticket because of redirects performed by CAS.

 *

 */

function _cas_single_sign_out_save_ticket() {

  if (isset($_GET['ticket'])) {

    $_SESSION['cas_ticket'] = $_GET['ticket'];

  }

}

/**

 * Determine whether a CAS user is blocked.

 *

 * @param $cas_name

 *   The CAS username.

 *

 * @return

 *   Boolean TRUE if the user is blocked, FALSE if the user is active.

 */

function _cas_external_user_is_blocked($cas_name) {

  return db_query("SELECT name FROM {users} u JOIN {cas_user} c ON u.uid = c.uid WHERE u.status = 0 AND c.cas_name = :cas_name", array(':cas_name' => $cas_name))->fetchField();

}

/**

 * Invokes hook_cas_user_TYPE() in every module.

 *

 * We cannot use module_invoke() because the arguments need to be passed by

 * reference.

 */

function cas_user_module_invoke($type, &$edit, $account) {

  foreach (module_implements('cas_user_' . $type) as $module) {

    $function = $module . '_cas_user_' . $type;

    $function($edit, $account);

  }

}

/**

 * Roles which should be granted to all CAS users.

 *

 * @return

 *   An associative array with the role id as the key and the role name as value.

 */

function cas_roles() {

  $cas_roles = &drupal_static(__FUNCTION__);

  if (!isset($cas_roles)) {

    $cas_roles = array_intersect_key(user_roles(), array_filter(variable_get('cas_auto_assigned_role', array(DRUPAL_AUTHENTICATED_RID => TRUE))));

  }

  return $cas_roles;

}

/**

 * Register a CAS user with some default values.

 *

 * @param $cas_name

 *   The name of the CAS user.

 * @param $options

 *   An associative array of options, with the following elements:

 *    - 'edit': An array of fields and values for the new user. If omitted,

 *      reasonable defaults are used.

 *    - 'invoke_cas_user_presave': Defaults to FALSE. Whether or not to invoke

 *      hook_cas_user_presave() on the newly created account.

 *

 * @return

 *   The user object of the created user, or FALSE if the user cannot be

 *   created.

 */

function cas_user_register($cas_name, $options = array()) {

  // Add some reasonable defaults if they have not yet been provided.

  $edit = isset($options['edit']) ? $options['edit'] : array();

  $edit += array(

    'name' => $cas_name,

    'pass' => user_password(),

    'init' => $cas_name,

    'mail' => variable_get('cas_domain', '') ? $cas_name . '@' . variable_get('cas_domain', '') : '',

    'status' => 1,

    'roles' => array(),

  );

  $edit['roles'] += cas_roles();

  $edit['cas_name'] = $cas_name;

  // See if the user name is already taken.

  if ((bool) db_select('users')->fields('users', array('name'))->condition('name', db_like($edit['name']), 'LIKE')->range(0, 1)->execute()->fetchField()) {

    return FALSE;

  }

  // Create the user account.

  $account = user_save(drupal_anonymous_user(), $edit);

  watchdog("user", 'new user: %n (CAS)', array('%n' => format_username($account)), WATCHDOG_NOTICE, l(t("edit user"), "user/edit/$account->uid"));

  if (!empty($options['invoke_cas_user_presave'])) {

    // Populate $edit with some basic properties.

    $edit = array(

      'cas_user' => array(

        'name' => $cas_name,

      ),

    );

    // Allow other modules to make their own custom changes.

    cas_user_module_invoke('presave', $edit, $account);

    // Clean up extra variables before saving.

    unset($edit['cas_user']);

    $account = user_save($account, $edit);

  }

  // Reload to ensure that we have a fully populated user object.

  return user_load($account->uid);

}

/**

 * Get the CAS attributes of the current CAS user.

 *

 * Ensures that phpCAS is properly initialized before getting the attributes.

 * @see phpCAS::getAttributes()

 *

 * @param $cas_name

 *   If provided, ensure that the currently logged in CAS user matches this

 *   CAS username.

 *

 * @return

 *   An associative array of CAS attributes.

 */

function cas_phpcas_attributes($cas_name = NULL) {

  if (isset($cas_name) && $cas_name != cas_current_user()) {

    // Attributes cannot be extracted for other users, since they are

    // stored in the session variable.

    return array();

  }

  cas_phpcas_init();

  if (phpCAS::isAuthenticated()) {

    if (method_exists('phpCAS', 'getAttributes')) {

      return phpCAS::getAttributes();

    }

  }

  return array();

}

/**

 * Insert an array into the specified position of another array.

 *

 * Preserves keys in associative arrays.

 * @see http://www.php.net/manual/en/function.array-splice.php#56794

 */

function _cas_array_insert(&$array, $position, $insert_array) {

  $first_array = array_splice($array, 0, $position);

  $array = array_merge($first_array, $insert_array, $array);

}

/**

 * Implements hook_views_api().

 */

function cas_views_api() {

  return array(

    'api' => 3,

    'path' => drupal_get_path('module', 'cas') . '/includes/views',

  );

}

/**

 * Redirect a user after they have logged into the website through CAS

 *

 * @param $cas_first_login - TRUE if this is the first time the CAS user

 * logged into the site

 */

function _cas_redirect_after_login($cas_first_login) {

  // When users first log in, we may want to redirect them to a special page if specified

  if ($cas_first_login && variable_get('cas_first_login_destination', '')) {

    $destination = variable_get('cas_first_login_destination', '');

    drupal_goto($destination);

  }

  else {

    // If logged in through forced authentication ('/cas'), then redirect user to the

    // homepage, or to wherever the current "destination" parameter points.

    if (strtolower(current_path()) == 'cas') {

      drupal_goto('');

    }

    // If logged in through gateway feature, then just reload the current path

    // and preserve any query string args that were set

    else {

      drupal_goto(current_path(), array('query' => drupal_get_query_parameters()));

    }

  }

}