How to use RavenDB queries in Data Layer or Classes?

Question

I have setup RavenDB embedded in my MVC application. I follower all the tutorials to make the RavenController and I can query the Session in the controller.

Now I would really like to break away from mixing data in the controller and create a Data layer so that I can do some Business logic which will help me create complex View Models.

How do I query the Session in a plain class file? I can't seem to find any info on how to do this.

Answer 1

Dependency Injection is great for this. You move aside the creation of the necessary services and let the container manage the lifecycle of the components, including scoping IDocumentSession to one instance per HTTP request.

As an example, using Autofac (you'd need both the Autofac and Autofac.Mvc5 packages) you could have a class in your App_Start folder like this, and then call AutofacConfig.Configure() from your Global.asax:

public static class AutofacConfig
{
    public static IContainer Container { get; private set; }

    public static void Configure()
    {
        var builder = new ContainerBuilder();
        var thisAssembly = Assembly.GetExecutingAssembly();

        // Register our controllers with the container
        builder.RegisterControllers(thisAssembly).PropertiesAutowired(PropertyWiringOptions.PreserveSetValues);

        // Provide injections of the HTTP abstractions (HttpContextBase, etc.)
        builder.RegisterModule(new AutofacWebTypesModule());

        // Create and register the Raven IDocumentStore
        builder.Register(c =>
        {
            var store = new DocumentStore {ConnectionStringName = "RavenDB"};
            store.Initialize();

            Raven.Client.Indexes.IndexCreation.CreateIndexes(typeof (MvcApplication).Assembly, store);

            return store;
        })
            .As<IDocumentStore>()
            .SingleInstance();

        // Provide injection of Raven IDocumentSession
        builder.Register(c => c.Resolve<IDocumentStore>().OpenSession())
            .InstancePerRequest();

        Container = builder.Build();
        DependencyResolver.SetResolver(new AutofacDependencyResolver(Container));
    }
}

Then, when you need an IDocumentSession some place outside of a controller:

// Business logic, or other class that injection is not provided for.
var session = AutofacConfig.Container.Resolve<IDocumentSession>();

Also include autofac otherwise you will get an error saying "does not contain definition Resolve ..."

using Autofac;

You can do similar things with most other DI container libraries; the API is just slightly different.