/// <summary>
        ///
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        public ActionResult Download(string id)
        {
            var book = db.Books.Find(new Guid(id));

            if (book == null)
            {
                return(new HttpNotFoundResult());
            }
            var extName = OpdsHelper.GetExtensionName(book.MimeType);

            return(new RangeFileResult(Request, HostingEnvironment.MapPath("~/App_Data/Uploaded/") + id + extName, book.Name + extName, book.MimeType));
        }
        public void GetExtensionNameTest()
        {
            var ext = OpdsHelper.GetExtensionName("text/plain");

            Assert.AreEqual(".txt", ext);
        }