请问WEBSOCKET如何获取域名后面的路径 ？

$ws = new Worker('Websocket://0.0.0.0:8181');
$ws->onConnect = function($connection)
{
    // websocket 握手时可以获得$_GET
    $connection->onWebSocketConnect = function($connection , $http_header)
    {
        var_dump($_GET);
    };
};