Files
moodle/lib/classes/session/handler.php

315 lines
9.8 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/>.
namespace core\session;
use core\clock;
use core\di;
use stdClass;
/**
* Session handler base.
*
* @package core
* @copyright 2013 Petr Skoda {@link http://skodak.org}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class handler {
/** @var boolean $requireswritelock does the session need and/or have a lock? */
protected $requireswritelock = false;
/**
* Start the session.
* @return bool success
*/
public function start() {
return session_start();
}
/**
* Write the session and release lock. If the session was not intentionally opened
* with a write lock, then we will abort the session instead if able.
*/
public function write_close() {
if ($this->requires_write_lock()) {
session_write_close();
$this->requireswritelock = false;
} else {
$this->abort();
}
}
/**
* Release lock on the session without writing it.
* May not be possible in older versions of PHP. If so, session may be written anyway
* so that any locks are released.
*/
public function abort() {
session_abort();
$this->requireswritelock = false;
}
/**
* This is called after init() and before start() to indicate whether the session
* opened should be writable or not. This is intentionally captured even if your
* handler doesn't support non-locking sessions, so that behavior (upon session close)
* matches closely between handlers.
* @param bool $requireswritelock true if needs to be open for writing
*/
public function set_requires_write_lock($requireswritelock) {
$this->requireswritelock = $requireswritelock;
}
/**
* Returns all session records.
*
* @return \Iterator
*/
public function get_all_sessions(): \Iterator {
global $DB;
$rs = $DB->get_recordset('sessions');
foreach ($rs as $row) {
yield $row;
}
$rs->close();
}
/**
* Returns a single session record for this session id.
*
* @param string $sid
* @return stdClass
*/
public function get_session_by_sid(string $sid): stdClass {
global $DB;
return $DB->get_record('sessions', ['sid' => $sid]) ?: new stdClass();
}
/**
* Returns all the session records for this user id.
*
* @param int $userid
* @return array
*/
public function get_sessions_by_userid(int $userid): array {
global $DB;
return $DB->get_records('sessions', ['userid' => $userid]);
}
/**
* Insert new empty session record.
*
* @param int $userid
* @return stdClass the new record
*/
public function add_session(int $userid): stdClass {
global $DB;
$record = new stdClass();
$record->state = 0;
$record->sid = session_id();
$record->sessdata = null;
$record->userid = $userid;
$record->timecreated = $record->timemodified = di::get(clock::class)->time();
$record->firstip = $record->lastip = getremoteaddr();
$record->id = $DB->insert_record('sessions', $record);
return $record;
}
/**
* Update a session record.
*
* @param stdClass $record
* @return bool
*/
public function update_session(stdClass $record): bool {
global $DB;
if (!isset($record->id) && isset($record->sid)) {
$record->id = $DB->get_field('sessions', 'id', ['sid' => $record->sid]);
}
return $DB->update_record('sessions', $record);
}
/**
* Destroy a specific session and delete this session record for this session id.
*
* @param string $id session id
* @return bool
*/
public function destroy(string $id): bool {
global $DB;
return $DB->delete_records('sessions', ['sid' => $id]);
}
/**
* Destroy all sessions, and delete all the session data.
*
* @return bool
*/
public function destroy_all(): bool {
global $DB;
return $DB->delete_records('sessions');
}
/**
* Clean up expired sessions.
*
* @param int $purgebefore Sessions that have not updated for the last purgebefore timestamp will be removed.
* @param int $userid
*/
protected function destroy_expired_user_sessions(int $purgebefore, int $userid): void {
$sessions = $this->get_sessions_by_userid($userid);
foreach ($sessions as $session) {
if ($session->timemodified < $purgebefore) {
$this->destroy($session->sid);
}
}
}
/**
* Clean up all expired sessions.
*
* @param int $purgebefore
*/
protected function destroy_all_expired_sessions(int $purgebefore): void {
global $DB, $CFG;
$authsequence = get_enabled_auth_plugins();
$authsequence = array_flip($authsequence);
unset($authsequence['nologin']); // No login means user cannot login.
$authsequence = array_flip($authsequence);
$authplugins = [];
foreach ($authsequence as $authname) {
$authplugins[$authname] = get_auth_plugin($authname);
}
$sql = "SELECT u.*, s.sid, s.timecreated AS s_timecreated, s.timemodified AS s_timemodified
FROM {user} u
JOIN {sessions} s ON s.userid = u.id
WHERE s.timemodified < :purgebefore AND u.id <> :guestid";
$params = ['purgebefore' => $purgebefore, 'guestid' => $CFG->siteguest];
$rs = $DB->get_recordset_sql($sql, $params);
foreach ($rs as $user) {
foreach ($authplugins as $authplugin) {
if ($authplugin->ignore_timeout_hook($user, $user->sid, $user->s_timecreated, $user->s_timemodified)) {
continue 2;
}
}
$this->destroy($user->sid);
}
$rs->close();
}
/**
* Destroy all sessions for a given plugin.
* Typically used when a plugin is disabled or uninstalled, so all sessions (users) for that plugin are logged out.
*
* @param string $pluginname Auth plugin name.
*/
public function destroy_by_auth_plugin(string $pluginname): void {
global $DB;
$rs = $DB->get_recordset('user', ['auth' => $pluginname], 'id ASC', 'id');
foreach ($rs as $user) {
$sessions = $this->get_sessions_by_userid($user->id);
foreach ($sessions as $session) {
$this->destroy($session->sid);
}
}
$rs->close();
}
// phpcs:disable moodle.NamingConventions.ValidVariableName.VariableNameUnderscore
/**
* Periodic timed-out session cleanup.
*
* @param int $max_lifetime Sessions that have not updated for the last max_lifetime seconds will be removed.
* @return int|false Number of deleted sessions or false if an error occurred.
*/
public function gc(int $max_lifetime = 0): int|false {
global $CFG;
// This may take a long time.
\core_php_time_limit::raise();
if ($max_lifetime === 0) {
$max_lifetime = (int) $CFG->sessiontimeout;
}
try {
// Calculate the timestamp before which sessions are considered expired.
$purgebefore = di::get(clock::class)->time() - $max_lifetime;
// Delete expired sessions for guest user account.
$this->destroy_expired_user_sessions($purgebefore, $CFG->siteguest);
// Delete expired sessions for userid = 0 (not logged in), better kill them asap to release memory.
$this->destroy_expired_user_sessions($purgebefore, 0);
// Clean up expired sessions for real users only.
$this->destroy_all_expired_sessions($purgebefore);
// Cleanup leftovers from the first browser access because it may set multiple cookies and then use only one.
$purgebefore = di::get(clock::class)->time() - (60 * 3);
$sessions = $this->get_sessions_by_userid(0);
foreach ($sessions as $session) {
if ($session->timemodified == $session->timecreated && $session->timemodified < $purgebefore) {
$this->destroy($session->sid);
}
}
} catch (\Exception $ex) {
debugging('Error gc-ing sessions: '.$ex->getMessage(), DEBUG_NORMAL, $ex->getTrace());
}
return 0;
}
// phpcs:enable
/**
* Has this session been opened with a writelock? Your handler should call this during
* start() if you support read-only sessions.
* @return bool true if session is intended to have a write lock.
*/
public function requires_write_lock() {
return $this->requireswritelock;
}
/**
* Init session handler.
*/
abstract public function init();
/**
* Check the backend contains data for this session id.
*
* Note: this is intended to be called from manager::session_exists() only.
*
* @param string $sid
* @return bool true if session found.
*/
abstract public function session_exists($sid);
}