shib_logout.php

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<?php
/*
        +-----------------------------------------------------------------------------+
        | ILIAS open source                                                           |
        +-----------------------------------------------------------------------------+
        | Copyright (c) 1998-2001 ILIAS open source, University of Cologne            |
        |                                                                             |
        | This program 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 2              |
        | of the License, or (at your option) any later version.                      |
        |                                                                             |
        | This program 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 this program; if not, write to the Free Software                 |
        | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. |
        +-----------------------------------------------------------------------------+
*/

// Just for debugging the WSDL part
ini_set("soap.wsdl_cache_enabled", "0"); // disabling WSDL cache

// Requirements:
// PHP 5 with SOAP support (should be available in default deployment)


// Front channel logout

// Note: Generally the back-channel logout should be used once the Shibboleth
//       Identity Provider supports Single Log Out!
//       Front-channel logout is not of much use.

if (
                isset($_GET['return'])
                && isset($_GET['action'])
                && $_GET['action'] == 'logout'
   ){
        
        // Load all the IILIAS stuff
        require_once "include/inc.header.php";
        
        global $ilAuth;
        
        // Logout out user from application
        // Destroy application session/cookie etc
        $ilAuth->logout();
        
        // Finally, send user to the return URL
        ilUtil::redirect($_GET['return']);
}

// Back channel logout //

// Note: This is the preferred logout channel because it also allows
//       administrative logout. However, it requires your application to be
//       adapated in the sense that the user's Shibboleth session ID must be
//       stored in the application's session data.
//       See function LogoutNotification below

elseif (!empty($HTTP_RAW_POST_DATA)) {
        
        // Load ILIAS libraries and initialise ILIAS in non-web context
        require_once("Services/Init/classes/class.ilInitialisation.php");
        $ilInit = new ilInitialisation();
        $GLOBALS['ilInit'] =& $ilInit;
        $ilInit->initILIAS('soap');
        
        // Set SOAP header
        $server = new SoapServer('https://'.$_SERVER['HTTP_HOST'].$_SERVER['PHP_SELF'].'/LogoutNotification.wsdl');
        $server->addFunction("LogoutNotification");
        $server->handle();
}

// Return WSDL

// Note: This is needed for the PHP SoapServer class.
//       Since I'm not a web service guru it might be that the code below is not
//       absolutely correct but at least it seems to to its job properly when it
//       comes to Shibboleth logout

else {

        header('Content-Type: text/xml');

        echo <<<WSDL
<?xml version ="1.0" encoding ="UTF-8" ?>
<definitions name="LogoutNotification"
  targetNamespace="urn:mace:shibboleth:2.0:sp:notify"
  xmlns:notify="urn:mace:shibboleth:2.0:sp:notify"
  xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
  xmlns="http://schemas.xmlsoap.org/wsdl/">

        <types>
           <schema targetNamespace="urn:mace:shibboleth:2.0:sp:notify"
                   xmlns="http://www.w3.org/2000/10/XMLSchema"
                   xmlns:notify="urn:mace:shibboleth:2.0:sp:notify">

                        <simpleType name="string">
                                <restriction base="string">
                                        <minLength value="1"/>
                                </restriction>
                        </simpleType>

                        <element name="OK" type="notify:OKType"/>
                        <complexType name="OKType">
                                <sequence/>
                        </complexType>

                </schema>
        </types>

        <message name="getLogoutNotificationRequest">
                <part name="SessionID" type="notify:string" />
        </message>

        <message name="getLogoutNotificationResponse" >
                <part name="OK"/>
        </message>

        <portType name="LogoutNotificationPortType">
                <operation name="LogoutNotification">
                        <input message="getLogoutNotificationRequest"/>
                        <output message="getLogoutNotificationResponse"/>
                </operation>
        </portType>

        <binding name="LogoutNotificationBinding" type="notify:LogoutNotificationPortType">
                <soap:binding style="rpc" transport="http://schemas.xmlsoap.org/soap/http"/>
                <operation name="LogoutNotification">
                        <soap:operation soapAction="urn:xmethods-logout-notification#LogoutNotification"/>
                </operation>
        </binding>

        <service name="LogoutNotificationService">
                  <port name="LogoutNotificationPort" binding="notify:LogoutNotificationBinding">
                        <soap:address location="https://{$_SERVER['HTTP_HOST']}{$_SERVER['PHP_SELF']}"/>
                  </port>
        </service>
</definitions>
WSDL;
        exit;

}

/******************************************************************************/
function LogoutNotification($SessionID){

        // Delete session of user using $SessionID to locate the user's session file
        // on the file system or in the database
        // Then delete this entry or record to clear the session
        // However, for that to work it is essential that the user's Shibboleth
        // SessionID is stored in the user session data!
        
        global $ilDB;
        
        $q = "SELECT session_id, data FROM usr_session WHERE expires > 'NOW()'";
        $r = $ilDB->query($q);
        
        while($session_entry = $r->fetchRow(DB_FETCHMODE_ASSOC)){
                
                $user_session = unserializesession($session_entry['data']);
                
                // Look for session with matching Shibboleth session id 
                // and then delete this ilias session
                foreach($user_session as $user_session_entry){
                        if ( 
                                   is_array($user_session_entry) 
                                && array_key_exists('shibboleth_session_id', $user_session_entry)
                                && $user_session_entry['shibboleth_session_id'] == $SessionID){
                                
                                // Delete this session entry
                                if (db_session_destroy($session_entry['session_id']) !== true){
                                        return new SoapFault('LogoutError', 'Could not delete session entry in database.');
                                }
                        }
                }
        }
        
        // If no SoapFault is returned, all is fine
}

/******************************************************************************/
// Deserializes session data and returns it in a hash array of arrays
function unserializesession( $serialized_string ){
        $variables = array( );
        $a = preg_split( "/(\w+)\|/", $serialized_string, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE );
        for( $i = 0; $i < count( $a ); $i = $i+2 ) {
                $variables[$a[$i]] = unserialize( $a[$i+1] );
        }
        return( $variables );
}

?>