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($sessionIdHash)
    {
        global $DIC;

        $ilDB = $DIC['ilDB'];
        $lng = $DIC['lng'];
        $ilClientIniFile = $DIC['ilClientIniFile'];

        $GLOBALS['DIC']->logger()->auth()->debug('Session reminder call for session id hash: ' . $sessionIdHash);

        // disable session writing and extension of expiration time
        ilSession::enableWebAccessWithoutSession(true);

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

        $res = $ilDB->queryF(
            '
                SELECT expires, user_id, data
                FROM usr_session
                WHERE MD5(session_id) = %s
            ',
            ['text'],
            [$sessionIdHash]
        );
        
        $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);
        }

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

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

        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'), ilDatePresentation::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;
    }
}