public async Task<IActionResult> Search(string q = "", int p = 1)
{
if (string.IsNullOrWhiteSpace(q)) Redirect("/");
var data = new PostData(Db);
var model = await data.SearchAsync(q, p);
if (model == null) Redirect("/");
ViewBag.PageCount = data.PageCount;
ViewBag.PageNo = p;
ViewBag.PagingUrl = $"/Search?q={q}&p={{p}}";
return View("Index", model);
}