UrlAliasPolicy.cs

[AttributeUsage(AttributeTargets.Method)]
public class UrlAliasAttribute : Attribute
{
    public UrlAliasAttribute(params string[] urls)
    {
        Urls = urls;
    }

    public string[] Urls { get; private set; }
}

[ConfigurationType(ConfigurationType.ModifyRoutes)]
public class UrlAliasConvention : IConfigurationAction
{
    public void Configure(BehaviorGraph graph)
    {
        graph.Actions()
            .Where(x => x.Method.HasAttribute<UrlAliasAttribute>())
            .SelectMany(x => x.Method.GetAttribute<UrlAliasAttribute>().Urls.Select(y => new { Url = y, Action = x }))
            .OrderByDescending(x => x.Url).ToList()
            .ForEach(x =>
            {
                var chain = new BehaviorChain();
                var call = new ActionCall(x.Action.HandlerType, x.Action.Method);
                chain.AddToEnd(call);
                chain.Route = call.BuildRouteForPattern(x.Url);
                x.Action.ParentChain().Route.AllowedHttpMethods.ForEach(y => chain.Route.AddHttpMethodConstraint(y));
                graph.AddChain(chain);
            });
    }
}