^^&&^^

Edit File: class-IXR-server.php

<?php

/**
 * IXR_Server
 *
 * @package IXR
 * @since 1.5.0
 */
class IXR_Server
{
    var $data;
    var $callbacks = array();
    var $message;
    var $capabilities;

/**
	 * PHP5 constructor.
	 */
    function __construct( $callbacks = false, $data = false, $wait = false )
    {
        $this->setCapabilities();
        if ($callbacks) {
            $this->callbacks = $callbacks;
        }
        $this->setCallbacks();
        if (!$wait) {
            $this->serve($data);
        }
    }

/**
	 * PHP4 constructor.
	 */
	public function IXR_Server( $callbacks = false, $data = false, $wait = false ) {
		self::__construct( $callbacks, $data, $wait );
	}

function serve($data = false)
    {
        if (!$data) {
            if (isset($_SERVER['REQUEST_METHOD']) && $_SERVER['REQUEST_METHOD'] !== 'POST') {
                if ( function_exists( 'status_header' ) ) {
                    status_header( 405 ); // WP #20986
                    header( 'Allow: POST' );
                }
                header('Content-Type: text/plain'); // merged from WP #9093
                die('XML-RPC server accepts POST requests only.');
            }

$data = file_get_contents('php://input');
        }
        $this->message = new IXR_Message($data);
        if (!$this->message->parse()) {
            $this->error(-32700, 'parse error. not well formed');
        }
        if ($this->message->messageType != 'methodCall') {
            $this->error(-32600, 'server error. invalid xml-rpc. not conforming to spec. Request must be a methodCall');
        }
        $result = $this->call($this->message->methodName, $this->message->params);

// Is the result an error?
        if (is_a($result, 'IXR_Error')) {
            $this->error($result);
        }

// Encode the result
        $r = new IXR_Value($result);
        $resultxml = $r->getXml();

// Create the XML
        $xml = <<<EOD
<methodResponse>
  <params>
    <param>
      <value>
      $resultxml
      </value>
    </param>
  </params>
</methodResponse>

EOD;
      // Send it
      $this->output($xml);
    }

function call($methodname, $args)
    {
        if (!$this->hasMethod($methodname)) {
            return new IXR_Error(-32601, 'server error. requested method '.$methodname.' does not exist.');
        }
        $method = $this->callbacks[$methodname];

// Perform the callback and send the response
        if (count($args) == 1) {
            // If only one parameter just send that instead of the whole array
            $args = $args[0];
        }

// Are we dealing with a function or a method?
        if (is_string($method) && substr($method, 0, 5) == 'this:') {
            // It's a class method - check it exists
            $method = substr($method, 5);
            if (!method_exists($this, $method)) {
                return new IXR_Error(-32601, 'server error. requested class method "'.$method.'" does not exist.');
            }

//Call the method
            $result = $this->$method($args);
        } else {
            // It's a function - does it exist?
            if (is_array($method)) {
                if (!is_callable(array($method[0], $method[1]))) {
                    return new IXR_Error(-32601, 'server error. requested object method "'.$method[1].'" does not exist.');
                }
            } else if (!function_exists($method)) {
                return new IXR_Error(-32601, 'server error. requested function "'.$method.'" does not exist.');
            }

// Call the function
            $result = call_user_func($method, $args);
        }
        return $result;
    }

function error($error, $message = false)
    {
        // Accepts either an error object or an error code and message
        if ($message && !is_object($error)) {
            $error = new IXR_Error($error, $message);
        }

$this->output($error->getXml());
    }

function output($xml)
    {
        $charset = function_exists('get_option') ? get_option('blog_charset') : '';
        if ($charset)
            $xml = '<?xml version="1.0" encoding="'.$charset.'"?>'."\n".$xml;
        else
            $xml = '<?xml version="1.0"?>'."\n".$xml;
        $length = strlen($xml);
        header('Connection: close');
        if ($charset)
            header('Content-Type: text/xml; charset='.$charset);
        else
            header('Content-Type: text/xml');
        header('Date: '.gmdate('r'));
        echo $xml;
        exit;
    }

function hasMethod($method)
    {
        return in_array($method, array_keys($this->callbacks));
    }

function setCapabilities()
    {
        // Initialises capabilities array
        $this->capabilities = array(
            'xmlrpc' => array(
                'specUrl' => 'http://www.xmlrpc.com/spec',
                'specVersion' => 1
        ),
            'faults_interop' => array(
                'specUrl' => 'http://xmlrpc-epi.sourceforge.net/specs/rfc.fault_codes.php',
                'specVersion' => 20010516
        ),
            'system.multicall' => array(
                'specUrl' => 'http://www.xmlrpc.com/discuss/msgReader$1208',
                'specVersion' => 1
        ),
        );
    }

function getCapabilities($args)
    {
        return $this->capabilities;
    }

function setCallbacks()
    {
        $this->callbacks['system.getCapabilities'] = 'this:getCapabilities';
        $this->callbacks['system.listMethods'] = 'this:listMethods';
        $this->callbacks['system.multicall'] = 'this:multiCall';
    }

function listMethods($args)
    {
        // Returns a list of methods - uses array_reverse to ensure user defined
        // methods are listed before server defined methods
        return array_reverse(array_keys($this->callbacks));
    }