drupal/includes/session.inc

369 lines
11 KiB
PHP

<?php
// $Id$
/**
* @file
* User session handling functions.
*
* The user-level session storage handlers:
* - _sess_open()
* - _sess_close()
* - _sess_read()
* - _sess_write()
* - _sess_destroy_sid()
* - _sess_gc()
* are assigned by session_set_save_handler() in bootstrap.inc and are called
* automatically by PHP. These functions should not be called directly. Session
* data should instead be accessed via the $_SESSION superglobal.
*/
/**
* Session handler assigned by session_set_save_handler().
*
* This function is used to handle any initialization, such as file paths or
* database connections, that is needed before accessing session data. Drupal
* does not need to initialize anything in this function.
*
* This function should not be called directly.
*
* @return
* This function will always return TRUE.
*/
function _sess_open() {
return TRUE;
}
/**
* Session handler assigned by session_set_save_handler().
*
* This function is used to close the current session. Because Drupal stores
* session data in the database immediately on write, this function does
* not need to do anything.
*
* This function should not be called directly.
*
* @return
* This function will always return TRUE.
*/
function _sess_close() {
return TRUE;
}
/**
* Session handler assigned by session_set_save_handler().
*
* This function will be called by PHP to retrieve the current user's
* session data, which is stored in the database. It also loads the
* current user's appropriate roles into the user object.
*
* This function should not be called directly. Session data should
* instead be accessed via the $_SESSION superglobal.
*
* @param $key
* Session ID.
* @return
* Either an array of the session data, or an empty string, if no data
* was found or the user is anonymous.
*/
function _sess_read($key) {
global $user;
// Write and Close handlers are called after destructing objects
// since PHP 5.0.5.
// Thus destructors can use sessions but session handler can't use objects.
// So we are moving session closure before destructing objects.
register_shutdown_function('session_write_close');
// Handle the case of first time visitors and clients that don't store
// cookies (eg. web crawlers).
if (!isset($_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_query("SELECT u.*, s.* FROM {users} u INNER JOIN {sessions} s ON u.uid = s.uid WHERE s.sid = :sid", array(':sid' => $key))->fetchObject();
// We found the client's session record and they are an authenticated user.
if ($user && $user->uid > 0) {
// 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';
$user->roles += db_query("SELECT r.rid, r.name FROM {role} r INNER JOIN {users_roles} ur ON ur.rid = r.rid WHERE ur.uid = :uid", array(':uid' => $user->uid))->fetchAllKeyed(0, 1);
}
// We didn't find the client's record (session has expired), or they
// are an anonymous user.
else {
$session = isset($user->session) ? $user->session : '';
$user = drupal_anonymous_user($session);
}
return $user->session;
}
/**
* Session handler assigned by session_set_save_handler().
*
* This function will be called by PHP to store the current user's
* session, which Drupal saves to the database.
*
* This function should not be called directly. Session data should
* instead be accessed via the $_SESSION superglobal.
*
* @param $key
* Session ID.
* @param $value
* Serialized array of the session data.
* @return
* This function will always return TRUE.
*/
function _sess_write($key, $value) {
global $user;
// If saving of session data is disabled, or if a new empty anonymous session
// has been started, do nothing. This keeps anonymous users, including
// crawlers, out of the session table, unless they actually have something
// stored in $_SESSION.
if (!drupal_save_session() || empty($user) || (empty($user->uid) && empty($_COOKIE[session_name()]) && empty($value))) {
return TRUE;
}
db_merge('sessions')
->key(array('sid' => $key))
->fields(array(
'uid' => $user->uid,
'cache' => isset($user->cache) ? $user->cache : 0,
'hostname' => ip_address(),
'session' => $value,
'timestamp' => REQUEST_TIME,
))
->execute();
// Last access time is updated no more frequently than once every 180 seconds.
// This reduces contention in the users table.
if ($user->uid && REQUEST_TIME - $user->access > variable_get('session_write_interval', 180)) {
db_update('users')
->fields(array(
'access' => REQUEST_TIME
))
->condition('uid', $user->uid)
->execute();
}
return TRUE;
}
/**
* Initialize the session handler, starting a session if needed.
*/
function drupal_session_initialize() {
global $user;
session_set_save_handler('_sess_open', '_sess_close', '_sess_read', '_sess_write', '_sess_destroy_sid', '_sess_gc');
if (isset($_COOKIE[session_name()])) {
// If a session cookie exists, initialize the session. Otherwise the
// session is only started on demand in drupal_session_commit(), making
// anonymous users not use a session cookie unless something is stored in
// $_SESSION. This allows HTTP proxies to cache anonymous pageviews.
drupal_session_start();
if (!empty($user->uid) || !empty($_SESSION)) {
drupal_page_is_cacheable(FALSE);
}
}
else {
// Set a session identifier for this request. This is necessary because
// we lazyly start sessions at the end of this request, and some
// processes (like drupal_get_token()) needs to know the future
// session ID in advance.
$user = drupal_anonymous_user();
session_id(md5(uniqid('', TRUE)));
}
}
/**
* Forcefully start a session, preserving already set session data.
*/
function drupal_session_start() {
if (!drupal_session_started()) {
// Save current session data before starting it, as PHP will destroy it.
$session_data = isset($_SESSION) ? $_SESSION : NULL;
session_start();
drupal_session_started(TRUE);
// Restore session data.
if (!empty($session_data)) {
$_SESSION += $session_data;
}
}
}
/**
* Commit the current session, if necessary.
*
* If an anonymous user already have an empty session, destroy it.
*/
function drupal_session_commit() {
global $user;
if (empty($user->uid) && empty($_SESSION)) {
if (drupal_session_started()) {
// Destroy empty anonymous sessions.
session_destroy();
}
}
else {
if (!drupal_session_started()) {
drupal_session_start();
}
// Write the session data.
session_write_close();
}
}
/**
* Return whether a session has been started.
*/
function drupal_session_started($set = NULL) {
static $session_started = FALSE;
if (isset($set)) {
$session_started = $set;
}
return $session_started && session_id();
}
/**
* Called when an anonymous user becomes authenticated or vice-versa.
*/
function drupal_session_regenerate() {
global $user;
// Set the session cookie "httponly" flag to reduce the risk of session
// stealing via XSS.
extract(session_get_cookie_params());
session_set_cookie_params($lifetime, $path, $domain, $secure, TRUE);
if (drupal_session_started()) {
$old_session_id = session_id();
session_regenerate_id();
}
else {
// Start the session when it doesn't exist yet.
// Preserve the logged in user, as it will be reset to anonymous
// by _sess_read.
$account = $user;
drupal_session_start();
$user = $account;
}
if (isset($old_session_id)) {
db_update('sessions')
->fields(array(
'sid' => session_id()
))
->condition('sid', $old_session_id)
->execute();
}
}
/**
* Counts how many users are active on the site.
*
* Counts how many users have sessions which have been active since the
* specified time. Can count either anonymous sessions or
* authenticated sessions.
*
* @param int $timestamp.
* A Unix timestamp. Users who have been active since this time will be
* counted. The default is 0, which counts all existing sessions.
* @param boolean $anonymous
* TRUE counts only anonymous users.
* FALSE counts only authenticated users.
* @return int
* The number of users with sessions.
*/
function drupal_session_count($timestamp = 0, $anonymous = TRUE) {
$query = db_select('sessions');
$query->addExpression('COUNT(sid)', 'count');
$query->condition('timestamp', $timestamp, '>=');
$query->condition('uid', 0, $anonymous ? '=' : '>');
return $query->execute()->fetchField();
}
/**
* Session handler assigned by session_set_save_handler().
*
* Cleanup a specific session.
*
* @param string $sid
* Session ID.
*/
function _sess_destroy_sid($sid) {
db_delete('sessions')
->condition('sid', $sid)
->execute();
// Unset cookie.
extract(session_get_cookie_params());
setcookie(session_name(), '', time() - 3600, $path, $domain, $secure, $httponly);
}
/**
* End a specific user's session(s).
*
* @param string $uid
* User ID.
*/
function drupal_session_destroy_uid($uid) {
db_delete('sessions')
->condition('uid', $uid)
->execute();
}
/**
* Session handler assigned by session_set_save_handler().
*
* Cleanup stalled sessions.
*
* @param int $lifetime
* The value of session.gc_maxlifetime, passed by PHP.
* Sessions not updated for more than $lifetime seconds will be removed.
*/
function _sess_gc($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_delete('sessions')
->condition('timestamp', REQUEST_TIME - $lifetime, '<')
->execute();
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 $status
* Disables writing of session data when FALSE, (re-)enables
* writing when TRUE.
* @return
* FALSE if writing session data has been disabled. Otherwise, TRUE.
*/
function drupal_save_session($status = NULL) {
$save_session = &drupal_static(__FUNCTION__, TRUE);
if (isset($status)) {
$save_session = $status;
}
return $save_session;
}