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;

        static function _getData($a_session_id)
        {
                if(!$a_session_id) {
                        return NULL;
                }
                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);
        
                return $rec["data"];
        }
        
        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;
                }

                $now = time();

                // prepare session data
                $fields = array(
                        "user_id" => array("integer", (int) $_SESSION["AccountId"]),
                        "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))
                {
                        $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);
                        
                        $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
                if(rand(0, 50) == 2)
                {
                        // get time _before_ destroying expired sessions                
                        self::_destroyExpiredSessions();        
                    ilSessionStatistics::aggretateRaw($now);
                }
                
                return true;
        }



        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;
        }

        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;
        }

        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;
        }

        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;
        }
        
        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() + ini_get('session.gc_maxlifetime');
                }
                else if( $ilSetting->get('session_handling_type', self::SESSION_HANDLING_FIXED) == self::SESSION_HANDLING_LOAD_DEPENDENT )
                {
                        // load dependent session settings
                        return time() + (int) ($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');
                }
                else if( $ilSetting->get('session_handling_type', self::SESSION_HANDLING_FIXED) ==  self::SESSION_HANDLING_LOAD_DEPENDENT )
                {
                        // load dependent session settings
                        return (int) ($ilSetting->get('session_max_idle', ilSessionControl::DEFAULT_MAX_IDLE) * 60);
                }
        }
        
        public static function getSessionExpireValue()
        {
                return self::getIdleValue(true);
        }
        
        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;
        }
        
        static function set($a_var, $a_val)
        {
                $_SESSION[$a_var] = $a_val;
        }
        
        static function get($a_var)
        {
                return $_SESSION[$a_var];
        }
        
        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;
        }
}

?>