One Controller is Sometimes Bound Twice with Ninject
- by Dusda
I have the following NinjectModule, where we bind our repositories and business objects:
/// <summary>
/// Used by Ninject to bind interface contracts to concrete types.
/// </summary>
public class ServiceModule : NinjectModule
{
/// <summary>
/// Loads this instance.
/// </summary>
public override void Load()
{
//bindings here.
//Bind<IMyInterface>().To<MyImplementation>();
Bind<IUserRepository>().To<SqlUserRepository>();
Bind<IHomeRepository>().To<SqlHomeRepository>();
Bind<IPhotoRepository>().To<SqlPhotoRepository>();
//and so on
//business objects
Bind<IUser>().To<Data.User>();
Bind<IHome>().To<Data.Home>();
Bind<IPhoto>().To<Data.Photo>();
//and so on
}
}
And here are the relevant overrides from our Global.asax, where we inherit from NinjectHttpApplication in order to integrate it with Asp.Net Mvc (The module lies in a separate dll called Thing.Web.Configuration):
protected override void OnApplicationStarted()
{
base.OnApplicationStarted();
//routes and areas
AreaRegistration.RegisterAllAreas();
RegisterRoutes(RouteTable.Routes);
//Initializes a singleton that must reference this HttpApplication class,
//in order to provide the Ninject Kernel to the rest of Thing.Web. This
//is necessary because there are a few instances (currently Membership)
//that require manual dependency injection.
NinjectKernel.Instance = new NinjectKernel(this);
//view model factory.
NinjectKernel.Instance.Kernel.Bind<IModelFactory>().To<MasterModelFactory>();
}
protected override NinjectControllerFactory CreateControllerFactory()
{
return base.CreateControllerFactory();
}
protected override Ninject.IKernel CreateKernel()
{
var kernel = new StandardKernel();
kernel.Load("Thing.Web.Configuration.dll");
return kernel;
}
Now, everything works great, with one exception: For some reason, sometimes Ninject will bind the PhotoController twice. This leads to an ActivationException, because Ninject can't discern which PhotoController I want. This causes all requests for thumbnails and other user images on the site to fail.
Here is the PhotoController in it's entirety:
public class PhotoController : Controller
{
public PhotoController()
{
}
public ActionResult Index(string id)
{
var dir = Server.MapPath("~/" + ConfigurationManager.AppSettings["UserPhotos"]);
var path = Path.Combine(dir, id);
return base.File(path, "image/jpeg");
}
}
Every controller works in exactly the same way, but for some reason the PhotoController gets double-bound. Even then, it only happens occasionally (either when re-building the solution, or on staging/production when the app pool kicks in). Once this happens, it continues to happen until I redeploy without changing anything.
So...what's up with that?
