class.ilSession.php

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<?php
/* Copyright (c) 1998-2009 ILIAS open source, Extended GPL, see docs/LICENSE */

require_once('Services/Authentication/classes/class.ilSessionControl.php');
require_once('Services/Authentication/classes/class.ilSessionStatistics.php');
require_once('Services/Authentication/classes/class.ilSessionIStorage.php');

class ilSession
{
    const SESSION_HANDLING_FIXED = 0;
    
    const SESSION_HANDLING_LOAD_DEPENDENT = 1;
    
    const SESSION_CLOSE_USER   = 1;  // manual logout
    const SESSION_CLOSE_EXPIRE = 2;  // has expired
    const SESSION_CLOSE_FIRST  = 3;  // kicked by session control (first abidencer)
    const SESSION_CLOSE_IDLE   = 4;  // kickey by session control (ilde time)
    const SESSION_CLOSE_LIMIT  = 5;  // kicked by session control (limit reached)
    const SESSION_CLOSE_LOGIN  = 6;  // anonymous => login
    const SESSION_CLOSE_PUBLIC = 7;  // => anonymous
    const SESSION_CLOSE_TIME   = 8;  // account time limit reached
    const SESSION_CLOSE_IP     = 9;  // wrong ip
    const SESSION_CLOSE_SIMUL  = 10; // simultaneous login
    const SESSION_CLOSE_INACTIVE = 11; // inactive account
    const SESSION_CLOSE_CAPTCHA  = 12; // invalid captcha
    
    private static $closing_context = null;

    protected static $enable_web_access_without_session = false;

    public static function _getData($a_session_id)
    {
        if (!$a_session_id) {
            // fix for php #70520
            return '';
        }
        global $ilDB;
        
        $q = "SELECT data FROM usr_session WHERE session_id = " .
            $ilDB->quote($a_session_id, "text");
        $set = $ilDB->query($q);
        $rec = $ilDB->fetchAssoc($set);
    
        // fix for php #70520
        return (string) $rec["data"];
    }
    
    public static function lookupExpireTime($a_session_id)
    {
        global $ilDB;
        
        $query = 'SELECT expires FROM usr_session WHERE session_id = ' .
            $ilDB->quote($a_session_id, 'text');
        $res = $ilDB->query($query);
        while ($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT)) {
            return (int) $row->expires;
        }
        return 0;
    }


    public static function _writeData($a_session_id, $a_data)
    {
        global $ilDB, $ilClientIniFile;
        
        if (self::isWebAccessWithoutSessionEnabled()) {
            // Prevent session data written for web access checker
            // when no cookie was sent (e.g. for pdf files linking others).
            // This would result in new session records for each request.
            return true;
        }

        if (!$a_session_id) {
            return true;
        }

        $now = time();

        // prepare session data
        $fields = array(
            "user_id" => array("integer", (int) $_SESSION['_authsession_user_id']),
            "expires" => array("integer", self::getExpireValue()),
            "data" => array("clob", $a_data),
            "ctime" => array("integer", $now),
            "type" => array("integer", (int) $_SESSION["SessionType"])
            );
        if ($ilClientIniFile->readVariable("session", "save_ip")) {
            $fields["remote_addr"] = array("text", $_SERVER["REMOTE_ADDR"]);
        }

        if (ilSession::_exists($a_session_id)) {
            // note that we do this only when inserting the new record
            // updating may get us other contexts for the same session, especially ilContextWAC, which we do not want
            if (class_exists("ilContext")) {
                if (ilContext::isSessionMainContext()) {
                    $fields["context"] = array("text", ilContext::getType());
                }
            }

            $ilDB->update(
                "usr_session",
                $fields,
                array("session_id" => array("text", $a_session_id))
            );
        } else {
            $fields["session_id"] = array("text", $a_session_id);
            $fields["createtime"] = array("integer", $now);

            // note that we do this only when inserting the new record
            // updating may get us other contexts for the same session, especially ilContextWAC, which we do not want
            if (class_exists("ilContext")) {
                $fields["context"] = array("text", ilContext::getType());
            }

            $ilDB->insert("usr_session", $fields);
        
            // check type against session control
            $type = $fields["type"][1];
            if (in_array($type, ilSessionControl::$session_types_controlled)) {
                ilSessionStatistics::createRawEntry(
                    $fields["session_id"][1],
                    $type,
                    $fields["createtime"][1],
                    $fields["user_id"][1]
                );
            }
        }
        
        // finally delete deprecated sessions
        $random = new \ilRandom();
        if ($random->int(0, 50) == 2) {
            // get time _before_ destroying expired sessions
            self::_destroyExpiredSessions();
            ilSessionStatistics::aggretateRaw($now);
        }
        
        return true;
    }



    public static function _exists($a_session_id)
    {
        if (!$a_session_id) {
            return false;
        }
        global $ilDB;

        $q = "SELECT 1 FROM usr_session WHERE session_id = " . $ilDB->quote($a_session_id, "text");
        $set = $ilDB->query($q);

        return $ilDB->numRows($set) > 0;
    }

    public static function _destroy($a_session_id, $a_closing_context = null, $a_expired_at = null)
    {
        global $ilDB;
        
        if (!$a_closing_context) {
            $a_closing_context = self::$closing_context;
        }
            
        ilSessionStatistics::closeRawEntry($a_session_id, $a_closing_context, $a_expired_at);
        
        
        if (!is_array($a_session_id)) {
            $q = "DELETE FROM usr_session WHERE session_id = " .
                $ilDB->quote($a_session_id, "text");
        } else {
            // array: id => timestamp - so we get rid of timestamps
            if ($a_expired_at) {
                $a_session_id = array_keys($a_session_id);
            }
            $q = "DELETE FROM usr_session WHERE " .
                $ilDB->in("session_id", $a_session_id, "", "text");
        }

        ilSessionIStorage::destroySession($a_session_id);

        $ilDB->manipulate($q);
        
        return true;
    }

    public static function _destroyByUserId($a_user_id)
    {
        global $ilDB;

        $q = "DELETE FROM usr_session WHERE user_id = " .
            $ilDB->quote($a_user_id, "integer");
        $ilDB->manipulate($q);
        
        return true;
    }

    public static function _destroyExpiredSessions()
    {
        global $ilDB;
                
        $q = "SELECT session_id,expires FROM usr_session WHERE expires < " .
            $ilDB->quote(time(), "integer");
        $res = $ilDB->query($q);
        $ids = array();
        while ($row = $ilDB->fetchAssoc($res)) {
            $ids[$row["session_id"]] = $row["expires"];
        }
        if (sizeof($ids)) {
            self::_destroy($ids, self::SESSION_CLOSE_EXPIRE, true);
        }
        
        return true;
    }
    
    public static function _duplicate($a_session_id)
    {
        global $ilDB;
    
        // Create new session id
        $new_session = $a_session_id;
        do {
            $new_session = md5($new_session);
            $q ="SELECT * FROM usr_session WHERE " .
                "session_id = " . $ilDB->quote($new_session, "text");
            $res = $ilDB->query($q);
        } while ($ilDB->fetchAssoc($res));
        
        $query = "SELECT * FROM usr_session " .
            "WHERE session_id = " . $ilDB->quote($a_session_id, "text");
        $res = $ilDB->query($query);

        while ($row = $ilDB->fetchObject($res)) {
            ilSession::_writeData($new_session, $row->data);
            return $new_session;
        }
        return false;
    }
    
    public static function getExpireValue($fixedMode = false)
    {
        global $ilSetting;
        
        if ($fixedMode || $ilSetting->get('session_handling_type', self::SESSION_HANDLING_FIXED) == self::SESSION_HANDLING_FIXED) {
            // fixed session
            return time() + self::getIdleValue($fixedMode);
        } elseif ($ilSetting->get('session_handling_type', self::SESSION_HANDLING_FIXED) == self::SESSION_HANDLING_LOAD_DEPENDENT) {
            // load dependent session settings
            return time() + (int) ($ilSetting->get('session_max_idle', ilSessionControl::DEFAULT_MAX_IDLE) * 60);
        }
    }

    public static function getIdleValue($fixedMode = false)
    {
        global $ilSetting, $ilClientIniFile;
        
        if ($fixedMode || $ilSetting->get('session_handling_type', self::SESSION_HANDLING_FIXED) ==  self::SESSION_HANDLING_FIXED) {
            // fixed session
            return $ilClientIniFile->readVariable('session', 'expire');
        } elseif ($ilSetting->get('session_handling_type', self::SESSION_HANDLING_FIXED) ==  self::SESSION_HANDLING_LOAD_DEPENDENT) {
            // load dependent session settings
            return (int) ($ilSetting->get('session_max_idle', ilSessionControl::DEFAULT_MAX_IDLE) * 60);
        }
    }
    
    public static function getSessionExpireValue()
    {
        return self::getIdleValue(true);
    }
    
    public static function _getUsersWithIp($a_ip)
    {
        global $ilDB;
        
        $query = "SELECT DISTINCT user_id FROM usr_session"
                . " WHERE remote_addr = " . $ilDB->quote($a_ip, "text")
                . " AND user_id > 0";
        $result = $ilDB->query($query);
        
        $users = array();
        while ($row = $ilDB->fetchObject($result)) {
            $users[] = $row->user_id;
        }
        return $users;
    }
    
    public static function set($a_var, $a_val)
    {
        $_SESSION[$a_var] = $a_val;
    }
    
    public static function get($a_var)
    {
        return $_SESSION[$a_var];
    }
    
    public static function clear($a_var)
    {
        unset($_SESSION[$a_var]);
    }
    
    public static function setClosingContext($a_context)
    {
        self::$closing_context = (int) $a_context;
    }
    
    public static function getClosingContext()
    {
        return self::$closing_context;
    }
    
    
        
    public static function isWebAccessWithoutSessionEnabled()
    {
        return (bool) self::$enable_web_access_without_session;
    }

    public static function enableWebAccessWithoutSession($enable_web_access_without_session)
    {
        self::$enable_web_access_without_session = (bool) $enable_web_access_without_session;
    }
}