public async Task <IActionResult> OnPostDownload(Guid id) { var stream = await downloadService.GetFile(id); var details = reviewService.LoadAnimations().Single(x => x.Id == id); if (stream == null || stream.Length == 0) { ModelState.AddModelError("", "Sikertelen letöltés!"); return(OnGet()); } return(File(stream, "application/octet-stream", $"{details.Name}.caff")); }