CookieTempDataProvider for ASP.NET

CookieTempDataProvider.cs

/*
To use the provider, you must override this method in your controllers:
protected override ITempDataProvider CreateTempDataProvider()
*/

using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
using System.Web;
using System.Web.Mvc;

namespace AppHarbor.Web.Mvc
{
	public class CookieTempDataProvider : ITempDataProvider
	{
		private const string CookieName = "TempData";

		private readonly IFormatter _formatter;

		public CookieTempDataProvider()
		{
			_formatter = new BinaryFormatter();
		}

		public IDictionary<string, object> LoadTempData(ControllerContext controllerContext)
		{
			HttpCookie cookie = controllerContext.HttpContext.Request.Cookies[CookieName];
			if (cookie != null && !string.IsNullOrEmpty(cookie.Value))
			{
				byte[] bytes = Convert.FromBase64String(cookie.Value);
				using (var stream = new MemoryStream(bytes))
				{
					return _formatter.Deserialize(stream) as IDictionary<string, object>;
				}
			}

			return new Dictionary<string, object>();
		}

		public void SaveTempData(ControllerContext controllerContext, IDictionary<string, object> values)
		{
			var cookie = new HttpCookie(CookieName);
			cookie.HttpOnly = true;

			if (values.Count == 0)
			{
				cookie.Expires = DateTime.Now.AddDays(-1);
				cookie.Value = string.Empty;
				controllerContext.HttpContext.Response.Cookies.Set(cookie);

				return;
			}

			using (var stream = new MemoryStream())
			{
				_formatter.Serialize(stream, values);
				var bytes = stream.ToArray();

				cookie.Value = Convert.ToBase64String(bytes);
			}
			controllerContext.HttpContext.Response.Cookies.Add(cookie);
		}
	}
}