StudentPortal - appCache example 2

using System;
using System.Collections.Generic;
using System.Web.Caching;
using System.Web.Mvc;
using StudentPortal.Repository;

namespace StudentPortal.Controllers
{
    public class HomeController : Controller
    {
        private BooksRepository _booksRepository = new BooksRepository();

        public ActionResult Index()
        {
            if (HttpContext.Cache["allBooks"] == null)
            {
                HttpContext.Cache.Insert("allBooks", _booksRepository.GetAll(), null,
                    DateTime.Now.AddHours(1), Cache.NoSlidingExpiration, CacheItemPriority.Default, null);
            }

            IEnumerable<Book> allBooks = HttpContext.Cache["allBooks"] as IEnumerable<Book>;
            return View(allBooks);
        }

        public ActionResult About()
        {
            ViewBag.SessionValue = Session["test"] != null ? Session["test"].ToString() : "Session is empty";

            return View();
        }

        public ActionResult Contact()
        {
            ViewBag.Message = "Your contact page.";

            return View();
        }

        [Authorize]
        public ActionResult MyPage()
        {
            var currentUser = User.Identity.Name;
            Session["test"] = "Session contains data for user " + currentUser;

            ViewBag.UserName = currentUser;
            if (HttpContext.Cache[currentUser] == null)
            {
                HttpContext.Cache.Insert(currentUser, _booksRepository.GetBooksForUser(currentUser), null,
                    DateTime.Now.AddHours(1), Cache.NoSlidingExpiration, CacheItemPriority.Default, null);
            }

            ViewBag.BooksRead = HttpContext.Cache[currentUser] as IEnumerable<Book>;

            return View();
        }
    }
}