/***
 * Excerpted from "Test Drive ASP.NET MVC",
 * published by The Pragmatic Bookshelf.
 * Copyrights apply to this code. It may not be used to create training material, 
 * courses, books, articles, and the like. Contact us if you are in doubt.
 * We make no guarantees that this code is fit for any purpose. 
 * Visit http://www.pragmaticprogrammer.com/titles/jmasp for more book information.
***/

public class NHibernateSessionStorage
{
  private const string CURRENT_SESSION_KEY = 
    "nhibernate.current_session";

  public static ISession RetrieveSession()
  {
    HttpContext context = HttpContext.Current; 
    if (!context.Items.Contains(CURRENT_SESSION_KEY)) OpenCurrent();
    var session = context.Items[CURRENT_SESSION_KEY] as ISession;
    return session;
  }

  private static void OpenCurrent() 
  {
    ISession session = NHibernateConfiguration.CreateAndOpenSession();
    HttpContext context = HttpContext.Current;
    context.Items[CURRENT_SESSION_KEY] = session;
  }

  public static void DisposeCurrent()
  {
    if (!HttpContext.Current.Items.Contains(CURRENT_SESSION_KEY)) 
      return; 
    ISession session = RetrieveSession();
    if (session != null && session.IsOpen)
        session.Close();
    HttpContext context = HttpContext.Current;
    context.Items.Remove(CURRENT_SESSION_KEY);
  }
}
public class NHibernateSessionStorage
{
  //omit start of class...

  public static ITransaction Transaction
  {
    get { return RetrieveSession().Transaction;}
  }
}