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Tom Marien

Passionate .NET Developer, Team Leader, living in Belgium

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There are many blog posts on how to manage the lifetime of ISession in a web application. Mainly because only ISessionFactory is thread-safe, which is a good thing because your ISession instance acts as a unit of work. For a web application the advised solution is to use the session-per-request pattern.

Even myself created one in the golden years, I’ve even posted it SourceForge a decade ago, but I’ve seem to have lost the link over the years. Coincidence, maybe?

I tend to include a container in my projects, why not let your container manage this for you? It knows about lifetime/lifestyle’s, so why reinventing the wheel again?


First we create a builder around the Configuration class, because i personally hate to put everything in an Xml file and I don’t believe my database of choice is going to change in the middle of my project. This is not a needed step, but it includes some goodies

using NHibernate.Cfg;
using NHibernate.Dialect;
using NHibernate.Driver;
using NHibernate.Mapping.ByCode;
using NHibernate.Tool.hbm2ddl;
namespace Nebula.Data
    public class NHibernateConfigurationBuilder
        private string connectionStringName;

        public NHibernateConfigurationBuilder()
            connectionStringName = "Nebula";

        public NHibernateConfigurationBuilder UsingNamedConnectionString(
            string connectionStringName)
            this.connectionStringName = connectionStringName;
            return this;

        public Configuration Build()
            var configuration = new Configuration();

            // initialize database configuration
            configuration.DataBaseIntegration(cfg =>
                cfg.ConnectionStringName = connectionStringName;
                cfg.KeywordsAutoImport = Hbm2DDLKeyWords.AutoQuote;

            // initialize mappers
            var mapper = new ModelMapper();

            // Auto Quote all table and column names
            return configuration;

The Installer

Wrap all registrations up in an installer and inject session anywhere you want

using Castle.MicroKernel.Registration;
using Castle.MicroKernel.SubSystems.Configuration;
using Castle.Windsor;
using NHibernate;
using Nebula.Data;
namespace Nebula.Bootstrapper.Installers
    public class NHibernateInstaller : IWindsorInstaller
        public void Install(IWindsorContainer container, IConfigurationStore store)
            ISessionFactory sessionfactory = new NHibernateConfigurationBuilder()


                    .UsingFactory<ISessionFactory, ISession>(
                        factory => factory.OpenSession())

For the registration of ISessionFactory i could have used a factory method, but that would delay any possible configuration mismatches until the first time a sessionfactory/session is needed.

If you have a usecase for IStatelessSession, append this to the installer and you are good to go:

             .UsingFactory<ISessionFactory, IStatelessSession>(
                    factory => factory.OpenStatelessSession())

Side note

The same mechanics can also be used to manage the lifetime of Entity framework’s objectcontext! Even if you are in a wcf context, just change the lifestyle of your session accordingly (see wcf facility).