public virtual IActionResult Qr(string u, int w = 200, int h = 200)
{
Response.Headers["Cache-Control"] = "max-age=315360000";
Response.Headers["Etag"] = DateTime.Now.ToString("yyyyMMddHHmmss");
Response.Headers["Date"] = DateTime.Now.ToString("r");
Response.Headers["Expires"] = DateTime.Now.AddYears(100).ToString("r");
var bytes = BarcodeHelper.CreateQrCode(System.Web.HttpUtility.UrlDecode(u), w, h);
return(File(bytes, "image/jpeg"));
}
