Custom user in ASP.NET MVC 2

Question

Hi,

I'm trying to implement a custom user object in ASP.NET MVC 2. I've seen a solution where you can do some magic in Global.asax to turn Controller.User into another type, say CustomUser. But Controller.User is still an IPrincipal, which means I have to cast it to CustomUser every time I want to use it, and I don't like that at all.

Would it be considered wrong, or bad practice, to have a a base controller with a GetUser() method, where GetUser() calls a user repository, and uses Controller.User to fetch our own custom user object?

What I'm trying to do is just add a couple of properties to the user object.

Answer 1

Would it be considered wrong, or bad practice, to have a a base controller with a GetUser() method, where GetUser() calls a user repository, and uses Controller.User to fetch our own custom user object?

I don't think so. This is the way I do it. ;)

Answer 2

That is the way to do it, however you would want to minimise the amount you need to cast the user object as to minimise violation of the Liskov Substitution Principle: http://en.wikipedia.org/wiki/Solid_%28object-oriented_design%29

Rather than casting it every time, is there not something you can bury away in an ActionFilter?

Answer 3

Here's what I would do:

In global.asax.cs

protected void Application_PostAuthorizeRequest()
{
    if (HttpContext.Current.User != null && HttpContext.Current.User.Identity != null && !string.IsNullOrEmpty(HttpContext.Current.User.Identity.Name))
    {
        HttpContext.Current.Items["User"] = userRepo.FetchByUsername(HttpContext.Current.User.Identity.Name);
    }
}

public static CustomUser CurrentUser
{
    get
    {
        return HttpContext.Current.Items["User"] as CustomUser;
    }
}

then you have a handy static with the current user in it. This is a dirty but effective way to do it.

Of course, really I would add the user into my IOC container and inject it into my controllers via an IOC enabled ControllerFactory. This is the 'correct' thing to do.

Whatever you do, don't use a base class! Using a static is probably more maintainable in the long run than creating an enormous base class with all the 'handy' things you need to get hold of.