Server.TransferRequest is completely unnecessary in MVC. This is an antiquated feature that was only necessary in ASP.NET because the request came directly to a page and there needed to be a way to transfer a request to another page. Modern versions of ASP.NET (including MVC) have a routing infrastructure that can be customized to route directly to the resource that is desired. There is no point of letting the request reach a controller only to transfer it to another controller when you can simply make the request go directly to the controller and action you want.
What's more is that since you are responding to the original request, there is no need to tuck anything into TempData or other storage just for the sake of routing the request to the right place. Instead, you arrive at the controller action with the original request intact. You also can be rest assured that Google will approve of this approach as it happens entirely on the server side.
While you can do quite a bit from both IRouteConstraint and IRouteHandler, the most powerful extension point for routing is the RouteBase subclass. This class can be extended to provide both incoming routes and outgoing URL generation, which makes it a one stop shop for everything having to do with the URL and the action that URL executes.
So, to follow your second example, to get from / to /home/7, you simply need a route that adds the appropriate route values.
public class RouteConfig
{
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
// Routes directy to `/home/7`
routes.MapRoute(
name: "Home7",
url: "",
defaults: new { controller = "Home", action = "Index", version = 7 }
);
routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
);
}
}
But going back to your original example where you have a random page, it is more complex because the route parameters cannot change at runtime. So, it could be done with a RouteBase subclass as follows.
public class RandomHomePageRoute : RouteBase
{
private Random random = new Random();
public override RouteData GetRouteData(HttpContextBase httpContext)
{
RouteData result = null;
// Only handle the home page route
if (httpContext.Request.Path == "/")
{
result = new RouteData(this, new MvcRouteHandler());
result.Values["controller"] = "Home";
result.Values["action"] = "Index";
result.Values["version"] = random.Next(10) + 1; // Picks a random number from 1 to 10
}
// If this isn't the home page route, this should return null
// which instructs routing to try the next route in the route table.
return result;
}
public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)
{
var controller = Convert.ToString(values["controller"]);
var action = Convert.ToString(values["action"]);
if (controller.Equals("Home", StringComparison.OrdinalIgnoreCase) &&
action.Equals("Index", StringComparison.OrdinalIgnoreCase))
{
// Route to the Home page URL
return new VirtualPathData(this, "");
}
return null;
}
}
Which can be registered in routing like:
public class RouteConfig
{
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
// Routes to /home/{version} where version is randomly from 1-10
routes.Add(new RandomHomePageRoute());
routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
);
}
}
Note in the above example, it might make sense to also store a cookie recording the home page version the user came in on so when they return they receive the same home page version.
Note also that using this approach you can customize routing to take query string parameters into consideration (it completely ignores them by default) and route to an appropriate controller action accordingly.
Additional Examples
