recursiveCall

public function recursiveCall($url, $depth)
    {
        if(!$this->isValid($url,$depth)) {
           return;
        }
        $this->_seen[$url] = true;

        $request = new AsyncWebRequest($url);
        if($request->start()) {
            while($request->isRunning()) {
                usleep(100);
            }
            if($request->join()) {
                if($request->response) {
                    $links = $this->processLinks($request->response,$url,$depth);
                    foreach($links as $link) {
                        $this->recursiveCall($link, $depth-1);
                    }
                }
            }
        }
    }