asp.net mvc 3 - What kind of route would I need to provide vanity urls?

Question

I'd like to provide my users a vanity url, something like:

www.foo.com/sergio

What kind of route would I need to create?

Imagine I have the following controller and action, how can I map a vanity URL to that controller?

public ActionResult Profile(string username)
{
    var model = LoadProfile(username);
    return View(model);
}

---

Here is what I've tried and what happens:

Option A:

Every url is caught in this route, meaning every URL I type directs me towards the Account controller, instead of only foo.com/[USERNAME]. No good.

public static void RegisterRoutes(RouteCollection routes)
{
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

    routes.MapRoute(
        "Profile",
        "{username}",
        new { controller = "Account", action = "Profile", username = UrlParameter.Optional }
    );

    routes.MapRoute(
        "Default", // Route name
        "{controller}/{action}/{id}", // URL with parameters
        new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
    );
}

---

Option B:

Default routes work well, but when trying to visit a profile foo.com/[USERNAME] I get an HTTP 404 error.

public static void RegisterRoutes(RouteCollection routes)
{
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

    routes.MapRoute(
        "Default", // Route name
        "{controller}/{action}/{id}", // URL with parameters
        new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
    );

    routes.MapRoute(
        "DentistProfile",
        "{username}",
        new { controller = "Account", action = "Profile", username = UrlParameter.Optional }
    );
}

Answer 1

one solution could be using custom route constraint as,

public class VanityUrlContraint : IRouteConstraint
{
    private static readonly string[] Controllers =
        Assembly.GetExecutingAssembly().GetTypes().Where(x => typeof(IController).IsAssignableFrom(x))
            .Select(x => x.Name.ToLower().Replace("controller", "")).ToArray();

    public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values,
                      RouteDirection routeDirection)
    {
        return !Controllers.Contains(values[parameterName].ToString().ToLower());
    }
}

and use it as

    routes.MapRoute(
        name: "Profile",
        url: "{username}",
        defaults: new {controller = "Account", action = "Profile"},
        constraints: new { username = new VanityUrlContraint() }
    );

    routes.MapRoute(
        name: "Default",
        url: "{controller}/{action}/{id}",
        defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
    );

downside of this approach, profile view for usernames same as existing controller name will not work, like if there are usernames like "asset", "location", and "AssetController", "LocationController" exists in project, profile view for "asset", "location" will not work.

hope this helps.