Petr Škoda d79d5ac276 MDL-31501 rework user session architecture
List of changes:
 * New OOP API using PHP namespace \core\session\.
 * All handlers now update the sessions table consistently.
 * Experimental DB session support in Oracle.
 * Full support for session file handler (filesystem locking required).
 * New option for alternative session directory.
 * Official memcached session handler support.
 * Workaround for memcached version with non-functional gc.
 * Improved security - forced session id regeneration.
 * Improved compatibility with recent PHP releases.
 * Fixed borked CSS during install in debug mode.
 * Switched to file based sessions in new installs.
 * DB session setting disappears if DB does not support sessions.
 * DB session setting disappears if session handler specified in config.php.
 * Fast purging of sessions used in request only.
 * No legacy distinction -  file, database and memcached support the same functionality.
 * Session handler name included in performance info.
 * Fixed user_loggedin and user_loggedout event triggering.
 * Other minor bugfixing and improvements.
 * Fixed database session segfault if MUC disposed before $DB.

Limitations:
 * Session access time is now updated right after session start.
 * Support for $CFG->sessionlockloggedinonly was removed.
 * First request does not update userid in sessions table.
 * The timeouts may break badly if server hosting forces PHP.ini session settings.
 * The session GC is a lot slower, we do not rely on external session timeouts.
 * There cannot be any hooks triggered at the session write time.
 * File and memcached handlers do not support session lock acquire timeouts.
 * Some low level PHP session functions can not be used directly in Moodle code.
2013-09-21 13:11:56 +02:00

121 lines
3.7 KiB
PHP

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* File based session handler.
*
* @package core
* @copyright 2013 Petr Skoda {@link http://skodak.org}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace core\session;
defined('MOODLE_INTERNAL') || die();
/**
* File based session handler.
*
* @package core
* @copyright 2013 Petr Skoda {@link http://skodak.org}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class file extends handler {
/** @var string session dir */
protected $sessiondir;
/**
* Create new instance of handler.
*/
public function __construct() {
global $CFG;
if (!empty($CFG->session_file_save_path)) {
$this->sessiondir = $CFG->session_file_save_path;
} else {
$this->sessiondir = "$CFG->dataroot/sessions";
}
}
/**
* Init session handler.
*/
public function init() {
if (preg_match('/^[0-9]+;/', $this->sessiondir)) {
throw new exception('sessionhandlerproblem', 'error', '', null, 'Multilevel session directories are not supported');
}
// Make sure session directory exists and is writable.
make_writable_directory($this->sessiondir, false);
if (!is_writable($this->sessiondir)) {
throw new exception('sessionhandlerproblem', 'error', '', null, 'Session directory is not writable');
}
// Need to disable debugging since disk_free_space()
// will fail on very large partitions (see MDL-19222).
$freespace = @disk_free_space($this->sessiondir);
if (!($freespace > 2048) and $freespace !== false) {
throw new exception('sessiondiskfull', 'error');
}
// NOTE: we cannot set any lock acquiring timeout here - bad luck.
ini_set('session.save_handler', 'files');
ini_set('session.save_path', $this->sessiondir);
}
/**
* Check for existing session with id $sid.
*
* Note: this verifies the storage backend only, not the actual session records.
*
* @param string $sid
* @return bool true if session found.
*/
public function session_exists($sid) {
$sid = clean_param($sid, PARAM_FILE);
if (!$sid) {
return false;
}
$sessionfile = "$this->sessiondir/sess_$sid";
return file_exists($sessionfile);
}
/**
* Kill all active sessions, the core sessions table is
* purged afterwards.
*/
public function kill_all_sessions() {
if (is_dir($this->sessiondir)) {
foreach (glob("$this->sessiondir/sess_*") as $filename) {
@unlink($filename);
}
}
}
/**
* Kill one session, the session record is removed afterwards.
* @param string $sid
*/
public function kill_session($sid) {
$sid = clean_param($sid, PARAM_FILE);
if (!$sid) {
return;
}
$sessionfile = "$this->sessiondir/sess_$sid";
if (file_exists($sessionfile)) {
@unlink($sessionfile);
}
}
}