How do I get an instance of IAppBuilder elsewhere

Question

I need to build an Owin middle-ware object but not from within the Startup class. I need to build it from within anywhere else in my code, so I need a reference to the AppBuilder instance of the application. Is there a way to get that from anywhere else?

Answer 1

You could simply inject AppBuilder itself to OwinContext. But since Owin context only supports IDisposable object, wrap it in IDisposable object and register it.

public class AppBuilderProvider : IDisposable
{
    private IAppBuilder _app;
    public AppBuilderProvider(IAppBuilder app)
    {
        _app = app;
    }
    public IAppBuilder Get() { return _app; }
    public void Dispose(){}
}

public class Startup
{
    // the startup method
    public void Configure(IAppBuilder app)
    {
        app.CreatePerOwinContext(() => new AppBuilderProvider(app));
        // another context registrations
    }
}

So in everywhere of your code you have access IAppBuilder object.

public class FooController : Controller
{
    public ActionResult BarAction()
    {
        var app = HttpContext.GetOwinContext().Get<AppBuilderProvider>().Get();
        // rest of your code.        
    }
}