Infinite loop when using cookieless session ID on Azure

public string GetSessionID(HttpContext context)
{
    var id = HttpContext.Current.Items["AspCookielessSession"] as string;
    // Azure web site does not support header "AspFilterSessionId", so we cannot get context.Items["AspCookielessSession"]
    // for azure web site use, Headers["X-Original-URL"] format: /(S(xxx))/default.aspx
    var originalUrl = HttpContext.Current.Request.Headers["X-Original-URL"];
    if (!string.IsNullOrEmpty(originalUrl))
    {
        var match = Regex.Match(HttpContext.Current.Request.Headers["X-Original-URL"], @"/\(S\((\w+)\)\)");
        if (match.Success)
        {
            id = match.Groups[1].Value;
        }
    }

    return id;
}