Random image name image upload MVC 4

Question

I am looking to generate a random name for the image that I upload in my MVC 4 Web App.

My Controller:

[HttpPost]
[ValidateAntiForgeryToken]
[ValidateInput(false)]
public ActionResult Create(Article article, HttpPostedFileBase file)
{
    if (ModelState.IsValid)
    {
        if (file != null && file.ContentLength > 0)
        {
            // extract only the filename
            var fileName = System.IO.Path.GetFileName(file.FileName);
            // store the file inside ~/App_Data/uploads folder
            var path = System.IO.Path.Combine(Server.MapPath("~/UploadedImages/Articles"), fileName);
            file.SaveAs(path);
            article.ArticleImage = file.FileName;
            ViewBag.Path = String.Format("~/UploadedImages/Events", fileName);
        }
        db.Articles.Add(article);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    ViewBag.SportID = new SelectList(db.Sports, "SportID", "Name", article.SportID);
    return View(article);
}

I have tried using GetRandomFileName method but with no luck. Not sure if this is the right way to do it.

Thanks in advance!

Answer 1

The simplest way is probably to use Guid.NewGuid() as the file name. It's pseudo random enough for most purposes and unique enough to have very low chances of creating a Guid that was created before.
You will need to extract the file extension from the original file name using Path's GetExtension method, and for that very low chances mentioned earlier, I would suggest writing a method like this:

string GenerateFileName(string TergetPath, HttpPostedFileBase file)
{
    string ReturnValue;
    string extension = Path.GetExtension(file.FileName);
    string FileName = Guid.NewGuid().ToString();
    ReturnValue = FileName + extension;
    if(!File.Exists(Path.Combine(TergetPath, ReturnValue)) 
    {
        return ReturnValue;
    }
    // This part creates a recursive pattern to ensure that you will not overwrite an existing file
    return GenerateFileName(TergetPath, file); 
}

Then you can call it from your existing code like this:

var DirectoryPath = Server.MapPath("~/UploadedImages/Articles");
var path = GenerateFileName(DirectoryPath, file);

Answer 2

You can use Guid.NewGuid() for generating random names, However here is an extension method that I use in my projects:

public static string UploadFile(HttpPostedFileBase file)
        {
            if (file != null)
            {
                var fileName = Path.GetFileName(file.FileName);
                var rondom = Guid.NewGuid() + fileName;
                var path = Path.Combine(HttpContext.Current.Server.MapPath("~/Content/Files/"), rondom);
                if (!Directory.Exists(HttpContext.Current.Server.MapPath("~/Content/Files/")))
                {
                    Directory.CreateDirectory(HttpContext.Current.Server.MapPath("~/Content/Files/"));
                }
                file.SaveAs(path);

                return rondom;
            }
            return "nofile.png";
        }