Autofac Getting the current identity

Question

I have a Service and virtually every method requires the current user to execute. Before I started using autofac I basically created a public property like this:

private IOrderProvider _orderProvider;

public IOrderProvider OrderProvider => _orderProvider ?? (_orderProvider = new OrderProvider((ClaimsIdentity)User.Identity));

Because this was a public property on the controller, it would have access to the User. Now using autofac I register my Service in the StartupConfig. Naturally I don't have access to the User there.

Is there a way to inject the current user into the OrderProvider constructor, or another way to get at it?

Answer 1

The user principal can be accessed through the HttpContext.Current.User. How ever tightly coupling code to HttpContext is frowned upon as it is not very unit test friendly. so create a service that exposes what you want.

using System.Security.Principal;
public interface IPrincipalProvider
{
    IPrincipal User { get; }
}

An implementation in production can look like this.

using System.Security.Principal;    
public class DefaultPrincipalProvider : IPrincipalProvider
{
    public IPrincipal User
    {
        get
        {
            return HttpContext.Current.User;
        }
    }
} 

With that done update the dependent class to use the abstraction

public class OrderProvider : IOrderProvider
{
    private readonly ClaimsIdentity identity;
    public OrderProvider(IPrincipalProvider provider) {
        identity = (ClaimsIdentity)provider.User.Identity;
    }
}

and then register the provider on startup as usual

//...other code removed for brevity

builder.RegisterType<DefaultPrincipalProvider>().As<IPrincipalProvider>();
builder.RegisterType<OrderProvider>().As<IOrderProvider>();

//...other code removed for brevity

The service should get everything injected

public class Service {
    private readonly IOrderProvider _orderProvider;

    public Service(IOrderProvider orderProvider) {
        _orderProvider = orderProvider;
    }

    public IOrderProvider OrderProvider => _orderProvider;
}