WC_Query::parse_request PHP Method

    public function parse_request()
    {
        global $wp;
        // Map query vars to their keys, or get them if endpoints are not supported
        foreach ($this->query_vars as $key => $var) {
            if (isset($_GET[$var])) {
                $wp->query_vars[$key] = $_GET[$var];
            } elseif (isset($wp->query_vars[$var])) {
                $wp->query_vars[$key] = $wp->query_vars[$var];
            }
        }
    }