Use Unity to resolve current NHibernate session for injection into Repositories - asp.net-mvc

Question

I have a multi-project MVC 5 solution, where NHibernate repositories are declared in a Core.Data class library, but my session management is in the Wen API Core.Api project. It creates and destroys a session per request:
public override void OnActionExecuting(HttpActionContext actionContext)
{
// start a session
var session = SessionFactory.OpenSession();
CurrentSessionContext.Bind(session);
session.BeginTransaction();
}
public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
{
// commit the current session
var session = SessionFactory.GetCurrentSession();
var transaction = session.Transaction;
if (transaction != null && transaction.IsActive)
{
transaction.Commit();
}
session = CurrentSessionContext.Unbind(SessionFactory);
session.Close();
}
Now when I instantiate a repository in a controller action,I would like this particular session to be injected into the repository. How can I achieve this? I can do a BaseRepository<T>: IRepository<T>, with a constructor that finds the session, but I would really much rather like it injected. How can I achieve this?

Answer 1

This is a snippet from how we do it.
public class UnityConfig
{
private static readonly Lazy<IUnityContainer> _container = new Lazy<IUnityContainer>(() =>
{
var container = new UnityContainer();
RegisterTypes(container);
return container;
});
//easy access to the container from anywhere in the application
public static T Resolve<T>()
{
//uses the Resolve<T> extension method
return GetConfiguredContainer().Resolve<T>();
}
private static void Register(IUnityContainer container)
{
container.RegisterType<IRepository, Repository>(
new InjectionConstructor(new ResolvedParameter<ISession>()));
container.RegisterType<ISession>(new PerRequestLifetimeManager(),
new InjectionFactory(c =>
c.Resolve<ISessionFactory>().OpenSession()
));
container
.RegisterType<ISessionFactory>(
new ContainerControlledLifetimeManager(),
new InjectionFactory(c =>
{
var v =
Fluently.Configure()
.Database(MsSqlConfiguration.MsSql2008
.ConnectionString(d => d.FromConnectionStringWithKey("web.config.connection.string.key"))
.ShowSql()
.Dialect<CustomOcMsSqlDialect>())
.Mappings(m => m.FluentMappings.AddFromAssemblyOf<IRepository>()
.Conventions.AddFromAssemblyOf<IRepository>())
.BuildSessionFactory();
return v;
})
);
}
}
public interface IRepository
{
}
public class Repository : IRepository
{
private readonly ISession _session;
public Repository(ISession session)
{
_session = session;
}
}
public class SomeController : Controller
{
public ActionResult SomeAction()
{
var repo = UnityConfig.Resolve<IRepository>();
var dbEntity = repo.Load(123);
return View("SomeView");
}
}
We wire up the repository, the session and the session-factory through unity. The factory is set to ContainerControlled(unity singleton). The session is set to PerRequest, so we get a new session for each request. And the repository uses the regular lifetime-manager so we get a new one for each resolve.
This way you can ask unity for a repository and get the same session throughout the entire request. It will also dispose the session automatically at the end of the request. But I'm sure you could hook into the ApplicationEndRequest event and do some housecleaning as well if you wanted.
Hope this helps!