Commit 79323857 authored by Steve Rude's avatar Steve Rude
Browse files

Initial Import of memcache sessions with database failover.

parent a88c06a9
<?php
// $Id$
/**
* @file
* User session handling functions.
*/
function sess_open($save_path, $session_name) {
return TRUE;
}
function sess_close() {
return TRUE;
}
function sess_read($key) {
global $user;
// Write and Close handlers are called after destructing objects since PHP 5.0.5
// Thus destructors can use sessions but session handler can't use objects.
// So we are moving session closure before destructing objects.
register_shutdown_function('session_write_close');
// Handle the case of first time visitors and clients that don't store cookies (eg. web crawlers).
if (!isset($_COOKIE[session_name()])) {
$user = drupal_anonymous_user();
return '';
}
// If user session is in memcache, use it, otherwise load from db.
$user = dmemcache_get($key, 'session');
if(!$user) {
$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'", $key));
}
if($user && $user->uid) {
if(!isset($user->roles)) {
$user = drupal_unpack($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;
}
}
} else {
$session = isset($user->session) ? $user->session : '';
$user = drupal_anonymous_user($session);
}
return $user->session;
}
function sess_write($key, $value) {
global $user;
// If the client doesn't have a session, and one isn't being created ($value), do nothing.
if(empty($_COOKIE[session_name()]) && empty($value)) {
return TRUE;
}
// If we have a session in memcache, lets keep track.
$in_memcache = dmemcache_get($key, 'session');
if(!$in_memcache) {
$result = db_query("SELECT sid FROM {sessions} WHERE sid = '%s'", $key);
$in_db = db_num_rows($result);
}
if(!$in_memcache) {
// Prepare the information to be saved
$info = new stdClass;
$info->sid = $key;
$info->uid = $user->uid;
$info->cache = $user->cache;
$info->hostname = $_SERVER["REMOTE_ADDR"];
$info->session = $value;
$info->timestamp = time();
$put_in_memcache = dmemcache_set($key, $info, ini_get('session.gc_maxlifetime'), 'session');
}
// First time the browser sends back the cookie, save to both db and memcache in case of memcache failure
if((!$in_db && !$in_memcache) && ($user->uid || $value || count($_COOKIE))) {
db_query("INSERT INTO {sessions} (sid, uid, cache, hostname, session, timestamp) VALUES ('%s', %d, %d, '%s', '%s', %d)", $key, $user->uid, $user->cache, $_SERVER["REMOTE_ADDR"], $value, time());
} else {
//TODO look at this again. Do we need to update memcache for any reason? on logout we'll just remove the memcache object
//For now, if memcache is running and the user object is there, why not ignore this for speed?
//db_query("UPDATE {sessions} SET uid = %d, cache = %d, hostname = '%s', session = '%s', timestamp = %d WHERE sid = '%s'", $user->uid, $user->cache, $_SERVER["REMOTE_ADDR"], $value, time(), $key);
// On memcache_set failure, we update the database
if(!$in_memcache && !$put_in_memcache) {
db_query("UPDATE {sessions} SET uid = %d, cache = %d, hostname = '%s', session = '%s', timestamp = %d WHERE sid = '%s'", $user->uid, $user->cache, $_SERVER["REMOTE_ADDR"], $value, time(), $key);
}
//Let's only update every 5 minutes for now.
/*
if(variable_get('session_access_update', 0) < time()) {
db_query("UPDATE {users} SET access = %d WHERE uid = %d", time(), $user->uid);
variable_set('session_access_update', time() + 300);
}
*/
}
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, '/');
}
session_regenerate_id();
$key = session_id();
// Grab the user's information that is cached with the anonymous key
$info = dmemcache_get($old_session_id, 'session');
if($info) {
// Update it.
$info->sid = $key;
// Store it with the new key.
dmemcache_set($key, $info, ini_get('session.gc_maxlifetime'), 'session');
// Clear the old data from the cache.
dmemcache_delete($old_session_id, 'session');
}
//Always keep the db synced with memcache in case of failure
db_query("UPDATE {sessions} SET sid = '%s' WHERE sid = '%s'", $key, $old_session_id);
}
/**
* Counts how many users have sessions. Can count either anonymous sessions, authenticated sessions, or both.
*
* @param int $timestamp
* A Unix timestamp representing a point of time in the past.
* The default is 0, which counts all existing sessions.
* @param int $anonymous
* TRUE counts only anonymous users.
* FALSE counts only authenticated users.
* Any other value will return the count of both authenticated and anonymous users.
* @return int
* The number of users with sessions.
*/
function sess_count($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) {
dmemcache_delete($sid, 'session');
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) {
dmemcache_delete($uid,'session');
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.
if(variable_get('session_gc_update', 0) < time()) {
db_query("DELETE FROM {sessions} WHERE timestamp < %d", time() - $lifetime);
variable_set('session_gc_update', time() + 300);
}
return TRUE;
}
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