shib_logout.php

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

// 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";

        // Logout out user from application
        // Destroy application session/cookie etc
        $GLOBALS['DIC']['ilAuthSession']->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)) {

        include_once "Services/Context/classes/class.ilContext.php";
        ilContext::init(ilContext::CONTEXT_SOAP);

        // Load ILIAS libraries and initialise ILIAS in non-web context
        require_once("Services/Init/classes/class.ilInitialisation.php");
        ilInitialisation::initILIAS();

        // Set SOAP header
        $server = new SoapServer('https://' . $_SERVER['HTTP_HOST'] . $_SERVER['SCRIPT_NAME'] . '/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');

        $url = filter_var("https://{$_SERVER['HTTP_HOST']}/shib_logout.php", FILTER_SANITIZE_URL);

        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="{$url}"/>
                  </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(ilDBConstants::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 (ilSession::_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);
}

?>