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Drupal example source code file (session.inc)

This example Drupal source code file (session.inc) is included in the DevDaily.com "Drupal Source Code Warehouse" project. The intent of this project is to help you "Learn Drupal by Example".

PHP - Drupal tags/keywords

array, database, function, php, return, session, sessions, sid, sql, time, uid, user, where

The session.inc Drupal example source code

// $Id: session.inc,v 2010/03/04 00:15:28 goba Exp $

 * @file
 * User session handling functions.

function sess_open($save_path, $session_name) {
  return TRUE;

function sess_close() {
  return TRUE;

function sess_read($key) {
  global $user;

  // Write and Close handlers are called after destructing objects since PHP 5.0.5
  // Thus destructors can use sessions but session handler can't use objects.
  // So we are moving session closure before destructing objects.

  // Handle the case of first time visitors and clients that don't store cookies (eg. web crawlers).
  if (!isset($_COOKIE[session_name()])) {
    $user = drupal_anonymous_user();
    return '';

  // Otherwise, if the session is still active, we have a record of the client's session in the database.
  $user = db_fetch_object(db_query("SELECT u.*, s.* FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.sid = '%s'", $key));

  // We found the client's session record and they are an authenticated,
  // active user.
  if ($user && $user->uid > 0 && $user->status == 1) {
    // This is done to unserialize the data member of $user
    $user = drupal_unpack($user);

    // Add roles element to $user
    $user->roles = array();
    $user->roles[DRUPAL_AUTHENTICATED_RID] = 'authenticated user';
    $result = db_query("SELECT r.rid, r.name FROM {role} r INNER JOIN {users_roles} ur ON ur.rid = r.rid WHERE ur.uid = %d", $user->uid);
    while ($role = db_fetch_object($result)) {
      $user->roles[$role->rid] = $role->name;
  // We didn't find the client's record (session has expired), or they are
  // blocked, or they are an anonymous user.
  else {
    $session = isset($user->session) ? $user->session : '';
    $user = drupal_anonymous_user($session);

  return $user->session;

function sess_write($key, $value) {
  global $user;

  // If saving of session data is disabled or if the client doesn't have a session,
  // and one isn't being created ($value), do nothing. This keeps crawlers out of
  // the session table. This reduces memory and server load, and gives more useful
  // statistics. We can't eliminate anonymous session table rows without breaking
  // the throttle module and the "Who's Online" block.
  if (!session_save_session() || ($user->uid == 0 && empty($_COOKIE[session_name()]) && empty($value))) {
    return TRUE;

  db_query("UPDATE {sessions} SET uid = %d, cache = %d, hostname = '%s', session = '%s', timestamp = %d WHERE sid = '%s'", $user->uid, isset($user->cache) ? $user->cache : '', ip_address(), $value, time(), $key);
  if (db_affected_rows()) {
    // Last access time is updated no more frequently than once every 180 seconds.
    // This reduces contention in the users table.
    if ($user->uid && time() - $user->access > variable_get('session_write_interval', 180)) {
      db_query("UPDATE {users} SET access = %d WHERE uid = %d", time(), $user->uid);
  else {
    // If this query fails, another parallel request probably got here first.
    // In that case, any session data generated in this request is discarded.
    @db_query("INSERT INTO {sessions} (sid, uid, cache, hostname, session, timestamp) VALUES ('%s', %d, %d, '%s', '%s', %d)", $key, $user->uid, isset($user->cache) ? $user->cache : '', ip_address(), $value, time());

  return TRUE;

 * Called when an anonymous user becomes authenticated or vice-versa.
function sess_regenerate() {
  $old_session_id = session_id();

  // We code around http://bugs.php.net/bug.php?id=32802 by destroying
  // the session cookie by setting expiration in the past (a negative
  // value).  This issue only arises in PHP versions before 4.4.0,
  // regardless of the Drupal configuration.
  // TODO: remove this when we require at least PHP 4.4.0
  if (isset($_COOKIE[session_name()])) {
    setcookie(session_name(), '', time() - 42000, '/');


  db_query("UPDATE {sessions} SET sid = '%s' WHERE sid = '%s'", session_id(), $old_session_id);

 * Counts how many users have sessions. Can count either anonymous sessions or authenticated sessions.
 * @param int $timestamp
 *   A Unix timestamp representing a point of time in the past.
 *   The default is 0, which counts all existing sessions.
 * @param boolean $anonymous
 *   TRUE counts only anonymous users.
 *   FALSE counts only authenticated users.
 * @return  int
 *   The number of users with sessions.
function sess_count($timestamp = 0, $anonymous = true) {
  $query = $anonymous ? ' AND uid = 0' : ' AND uid > 0';
  return db_result(db_query('SELECT COUNT(sid) AS count FROM {sessions} WHERE timestamp >= %d'. $query, $timestamp));

 * Called by PHP session handling with the PHP session ID to end a user's session.
 * @param  string $sid
 *   the session id
function sess_destroy_sid($sid) {
  db_query("DELETE FROM {sessions} WHERE sid = '%s'", $sid);

 * End a specific user's session
 * @param  string $uid
 *   the user id
function sess_destroy_uid($uid) {
  db_query('DELETE FROM {sessions} WHERE uid = %d', $uid);

function sess_gc($lifetime) {
  // Be sure to adjust 'php_value session.gc_maxlifetime' to a large enough
  // value. For example, if you want user sessions to stay in your database
  // for three weeks before deleting them, you need to set gc_maxlifetime
  // to '1814400'. At that value, only after a user doesn't log in after
  // three weeks (1814400 seconds) will his/her session be removed.
  db_query("DELETE FROM {sessions} WHERE timestamp < %d", time() - $lifetime);

  return TRUE;

 * Determine whether to save session data of the current request.
 * This function allows the caller to temporarily disable writing of session data,
 * should the request end while performing potentially dangerous operations, such as
 * manipulating the global $user object.  See http://drupal.org/node/218104 for usage
 * @param $status
 *   Disables writing of session data when FALSE, (re-)enables writing when TRUE.
 * @return
 *   FALSE if writing session data has been disabled. Otherwise, TRUE.
function session_save_session($status = NULL) {
  static $save_session = TRUE;
  if (isset($status)) {
    $save_session = $status;
  return ($save_session);

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