RIA Services: How can I create custom authentication?

Question

I am working with the Silverlight RIA Services and I want to create custom authentication. This appears to be the only thing that has virtually no documentation (I\'ve read

Answer 1

If you create a "Silverlight Business Application" you'll see how the template implements authentication. (Or just go here and download the template sample project.)

To simplify, here's the process I used:

First, I create a domain service (FooService) that derives from LinqToEntitiesDomainService where FooContext is my entity model. In it I add all the CRUD operations to access my custom DB table and return user profiles.

Next, create a concrete User class on the serverside by deriving from UserBase:

using System.Web.Ria;
using System.Web.Ria.ApplicationServices;

public class User : UserBase
{}

Finally, derive a class from AuthenticationBase and implement the following four methods:

[EnableClientAccess]
public class AuthenticationService : AuthenticationBase
{
    private FooService _service = new FooService();

    protected override bool ValidateUser(string username, string password)
    {
        // Code here that tests only if the password is valid for the given
        // username using your custom DB calls via the domain service you
        // implemented above
    }

    protected override User GetAuthenticatedUser(IPrincipal pricipal)
    {
        // principal.Identity.Name will be the username for the user
        // you're trying to authenticate. Here's one way to implement
        // this:
        User user = null;
        if (this._service.DoesUserExist(principal.Identity.Name)) // DoesUserExist() is a call
                                                                  // added in my domain service
        {
            // UserProfile is an entity in my DB
            UserProfile profile = this._service.GetUserProfile(principal.Identity.Name);
            user.Name = profile.UserName;
            user.AuthenticationType = principal.Identity.AuthenticationType;
        }
        return user;
    }

    public override void Initialize(DomainServiceContext context)
    {
        this._service.Initialize(context);
        base.Initialize(context);
    }

    protected override void Dispose(bool disposing)
    {
        if (disposing)
            this._service.Dispose();
        base.Dispose(disposing);
    }
}