Question

I have a service class UserService that gets an instance of IDocumentStore injected using AutoFac. This is working fine but now I’m looking at code like this:

public void Create(User user)
{
    using (var session = Store.OpenSession())
    {
        session.Store(user);
        session.SaveChanges();
    }
} 

Every action that writes to the db uses this same structure:

using (var session = Store.OpenSession())
{
    dosomething...
    session.SaveChanges();
}

What is the best way to eliminate this repetitive code?

Answer 1

The easiest way is implementing OnActionExecuting and OnActionExecuted on a base controller and use it.

let’s imagine you create your RavenController like this:

public class RavenController : Controller
{
    public IDocumentSession Session { get; set; }
    protected IDocumentStore _documentStore;

    public RavenController(IDocumentStore documentStore)
    {
        _documentStore = documentStore;
    }

    protected override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        Session = _documentStore.OpenSession();
        base.OnActionExecuting(filterContext);
    }

    protected override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        using (Session)
        {
            if (Session != null && filterContext.Exception == null)
            {
                Session.SaveChanges();
            }
        }
        base.OnActionExecuted(filterContext);
    }
}

then all you need to do in your own controllers is inherit from RavenController like this:

public class HomeController : RavenController
{
    public HomeController(IDocumentStore store)
        : base(store)
    {

    }

    public ActionResult CreateUser(UserModel model)
    {
        if (ModelState.IsValid)
        { 
            User user = Session.Load<User>(model.email);
            if (user == null) { 
                // no user found, let's create it
                Session.Store(model);
            }
            else {
                ModelState.AddModelError("", "That email already exists.");
            }
        }
        return View(model);
    }
}

---

Interesting enough, I have found a blog post showing exactly this technique …

it does explain way more that what I did. I hope it helps you better

Building an ASP.NET MVC app using RavenDB as a Backing Store