#Gocha#

<?php

// Implements logout for Shibboleth authenticated users according to:
// - https://spaces.internet2.edu/display/SHIB2/NativeSPLogoutInitiator
// - https://spaces.internet2.edu/display/SHIB2/NativeSPNotify

require_once("../../config.php");

require_once($CFG->dirroot."/auth/shibboleth/auth.php");

// Find out whether host supports https
$protocol = 'http://';
if ( isset($_SERVER['HTTPS']) && !empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on'){
    $protocol = 'https://';
}

// Front channel logout
if (
        isset($_GET['return'])
        && isset($_GET['action'])
        && $_GET['action'] == 'logout'
   ){

// Logout out user from application
    // E.g. destroy application session/cookie etc
    require_logout();

// Finally, send user to the return URL
    redirect($_GET['return']);
}

// Back channel logout
elseif (!empty($HTTP_RAW_POST_DATA)) {

// Requires PHP 5

// Set SOAP header
    $server = new SoapServer($protocol.$_SERVER['HTTP_HOST'].$_SERVER['PHP_SELF'].'/LogoutNotification.wsdl');

$server->addFunction("LogoutNotification");
    $server->handle();
}

// Return WSDL
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/">

<!--
This page either has to be called with the GET arguments 'action' and 'return' via
a redirect from the Shibboleth Service Provider logout handler (front-channel
logout) or via a SOAP request by a Shibboleth Service Provider (back-channel
logout).
Because neither of these two variants seems to be the case, the WSDL file for
the web service is returned.

For more information see:
- https://spaces.internet2.edu/display/SHIB2/NativeSPLogoutInitiator
- https://spaces.internet2.edu/display/SHIB2/NativeSPNotify
-->

</schema>
    </types>

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

}

/******************************************************************************/

function LogoutNotification($SessionID){

global $CFG, $SESSION, $DB;

// Delete session of user using $SessionID
    if(empty($CFG->dbsessions)) {

// File session
        $dir = $CFG->dataroot .'/sessions';
        if (is_dir($dir)) {
            if ($dh = opendir($dir)) {
                // Read all session files
                while (($file = readdir($dh)) !== false) {
                    // Check if it is a file
                    if (is_file($dir.'/'.$file)){
                        $session_key = preg_replace('/sess_/', '', $file);

// Read session file data
                        $data = file($dir.'/'.$file);
                        if (isset($data[0])){
                            $user_session = unserializesession($data[0]);

// Check if we have found session that shall be deleted
                            if (isset($user_session['SESSION']) && isset($user_session['SESSION']->shibboleth_session_id)){

// If there is a match, delete file
                                if ($user_session['SESSION']->shibboleth_session_id == $SessionID){
                                    // Delete session file
                                    if (!unlink($dir.'/'.$file)){
                                        return new SoapFault('LogoutError', 'Could not delete Moodle session file.');
                                    }
                                }
                            }
                        }
                    }
                }
                closedir($dh);
            }
        }
    } else {
        // DB Session
        //TODO: this needs to be rewritten to use new session stuff
        if (!empty($CFG->sessiontimeout)) {
            $ADODB_SESS_LIFE   = $CFG->sessiontimeout;
        }

if ($user_session_data = $DB->get_records_sql('SELECT sesskey, sessdata FROM {sessions2} WHERE expiry > NOW()')) {
            foreach ($user_session_data as $session_data) {

// Get user session
                $user_session = adodb_unserialize( urldecode($session_data->sessdata) );

if (isset($user_session['SESSION']) && isset($user_session['SESSION']->shibboleth_session_id)){

// If there is a match, delete file
                    if ($user_session['SESSION']->shibboleth_session_id == $SessionID){
                        // Delete this session entry
                        if (ADODB_Session::destroy($session_data->sesskey) !== true){
                            return new SoapFault('LogoutError', 'Could not delete Moodle session entry in database.');
                        }
                    }
                }
            }
        }
    }

// If now SoapFault was thrown the function will return OK as the SP assumes

}

/*****************************************************************************/

// Same function as in adodb, but cannot be used for file session for some reason...
function unserializesession($serialized_string) {
    $variables = array();
    $a = preg_split("/(\w+)\|/", $serialized_string, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE);
    $counta = count($a);
    for ($i = 0; $i < $counta; $i = $i+2) {
            $variables[$a[$i]] = unserialize($a[$i+1]);
    }
    return $variables;
}