class.ilSessionReminderCheck.php

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<?php
/* Copyright (c) 1998-2012 ILIAS open source, Extended GPL, see docs/LICENSE */

class ilSessionReminderCheck
{
        public function getJsonResponse($sessionId)
        {
                global $ilDB, $ilUser, $lng, $ilClientIniFile;

                include_once 'Services/JSON/classes/class.ilJsonUtil.php';

                $response = array('remind' => false);

                $res  = $ilDB->queryF('
                        SELECT expires, user_id, data
                        FROM usr_session
                        WHERE session_id = %s',
                        array('text'),
                        array($sessionId)
                );
                
                $num = $ilDB->numRows($res);

                if($num > 1)
                {
                        $response['message'] = 'The determined session data is not unique.';
                        return ilJsonUtil::encode($response);
                }

                if($num == 0)
                {
                        $response['message'] = 'ILIAS could not determine the session data.';
                        return ilJsonUtil::encode($response);
                }

                $data = $ilDB->fetchAssoc($res);
                if(!$this->isAuthenticatedUsrSession($data))
                {
                        $response['message'] = 'ILIAS could not fetch the session data or the corresponding user is no more authenticated.';
                        return ilJsonUtil::encode($response);
                }

                $session  = ilUtil::unserializeSession($data['data']);
                $idletime = null;
                foreach((array)$session as $key => $entry)
                {
                        if(strpos($key, '_auth__') === 0)
                        {
                                $idletime = $entry['idle'];
                                break;
                        }
                }

                if(null === $idletime)
                {
                        $response['message'] = 'ILIAS could not determine the idle time from the session data.';
                        return ilJsonUtil::encode($response);
                }

                $expiretime = $idletime + ilSession::getIdleValue();
                if($this->isSessionAlreadyExpired($expiretime))
                {
                        $response['message'] = 'The session is already expired. The client should have received a remind command before.';
                        return ilJsonUtil::encode($response);
                }

                $ilUser = ilObjectFactory::getInstanceByObjId($data['user_id']);

                include_once './Services/Authentication/classes/class.ilSessionReminder.php';
                $remind_time = $expiretime - max(ilSessionReminder::MIN_LEAD_TIME, (float)$ilUser->getPref('session_reminder_lead_time')) * 60;
                if($remind_time > time())
                {
                        // session will expire in <lead_time> minutes
                        $response['message'] = 'Lead time not reached, yet. Current time: ' . date('Y-m-d H:i:s', time()) . ', Reminder time: ' . date('Y-m-d H:i:s', $remind_time);
                        return ilJsonUtil::encode($response);
                }

                $dateTime = new ilDateTime($expiretime, IL_CAL_UNIX);
                switch($ilUser->getTimeFormat())
                {
                        case ilCalendarSettings::TIME_FORMAT_12:
                                $formatted_expiration_time = $dateTime->get(IL_CAL_FKT_DATE, 'g:ia', $ilUser->getTimeZone());
                                break;

                        case ilCalendarSettings::TIME_FORMAT_24:
                        default:
                                $formatted_expiration_time = $dateTime->get(IL_CAL_FKT_DATE, 'H:i', $ilUser->getTimeZone());
                                break;
                }

                $response = array(
                        'extend_url'               => './ilias.php?baseClass=ilPersonalDesktopGUI',
                        'txt'                      => str_replace("\\n", '%0A', sprintf($lng->txt('session_reminder_alert'), ilFormat::_secondsToString($expiretime - time()), $formatted_expiration_time, $ilClientIniFile->readVariable('client', 'name') . ' | ' . ilUtil::_getHttpPath())),
                        'remind'                   => true
                );

                return ilJsonUtil::encode($response);
        }

        protected function isSessionAlreadyExpired($expiretime)
        {
                return $expiretime < time();
        }

        protected function isAuthenticatedUsrSession($data)
        {
                return is_array($data) && isset($data['user_id']) && $data['user_id'] > 0 && $data['user_id'] != ANONYMOUS_USER_ID;
        }
}