Internal Server Error 500 on async upload asp mvc 5 - asp.net

Question

Just started using ASP.Net 4.5 and my API always returns Internal Server Error.
Upload API
public class UploadController : ApiController
{
public async Task<HttpResponseMessage> PostFile()
{
if (!Request.Content.IsMimeMultipartContent())
{
throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}
string root = HttpContext.Current.Server.MapPath("~/App_Data/uploads/");
var provider = new CustomMultipartFormDataStreamProvider(root);
try
{
await Request.Content.ReadAsMultipartAsync(provider);
return Request.CreateResponse(HttpStatusCode.OK);
}
catch (System.Exception e)
{
return Request.CreateErrorResponse(HttpStatusCode.InternalServerError, e);
}
}
}
My Controller
var message = new HttpRequestMessage();
var content = new MultipartFormDataContent();
message.Method = HttpMethod.Post;
message.Content = content;
message.RequestUri = new Uri("http://localhost:12345/api/upload/");
var client = new HttpClient();
client.SendAsync(message).ContinueWith(task =>
{
var result = task.Result.ReasonPhrase;
if (task.Result.IsSuccessStatusCode)
{
//do something
}
});
The files are saved in the location (/App_Data/uploads/) but why is the status code always 500?
Please enlighten me. Thanks

Answer 1

Here is part of working controller:
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<ActionResult> Create(Product product, HttpPostedFileBase file)
{
if (!ModelState.IsValid)
return PartialView("Create", product);
if (file != null)
{
var fileName = Path.GetFileName(file.FileName);
var guid = Guid.NewGuid().ToString();
var path = Path.Combine(Server.MapPath("~/Content/Uploads/ProductImages"), guid + fileName);
file.SaveAs(path);
string fl = path.Substring(path.LastIndexOf("\\"));
string[] split = fl.Split('\\');
string newpath = split[1];
string imagepath = "Content/Uploads/ProductImages/" + newpath;
using (MemoryStream ms = new MemoryStream())
{
file.InputStream.CopyTo(ms);
byte[] array = ms.GetBuffer();
}
var nId = Guid.NewGuid().ToString();
// Save record to database
product.Id = nId;
product.State = 1;
product.ImagePath = imagepath;
product.CreatedAt = DateTime.Now;
db.Products.Add(product);
await db.SaveChangesAsync();
TempData["message"] = "ProductCreated";
//return RedirectToAction("Index", product);
}
// after successfully uploading redirect the user
return Json(new { success = true });
}