public function createWSDL($force=false)
	{
	    $filename = $this->wsdl_path;
	    if (!file_exists($filename) || $force) {
	        $dir = dirname($filename);
	        if (!file_exists($dir)) {
	            $res = mkdir($dir, '0755', true);
	            if (!$res) {
	                echo 'create dir failure:' . $dir;
	                exit;
	            }
	        }
	        
	        $str = $this->getWSDL();
	        if (!$len = file_put_contents($filename, $str)) {
	            return false;
	        }
	    }
	    
	    return $this->wsdl_url;
	}