ASP.NET MVC Routing Via Method Attributes

Question

In the StackOverflow Podcast #54, Jeff mentions they register their URL routes in the StackOverflow codebase via an attribute above the method that handles the route. Sounds like a good concept (with the caveat that Phil Haack brought up regarding route priorities).

Could someone provide some sample to to make this happen?

Also, any "best practices" for using this style of routing?

Answer 1

This post is just to extend DSO's answer.

While converting my routes to attributes, I needed to handle the ActionName attribute. So in GetRouteParamsFromAttribute:

ActionNameAttribute anAttr = methodInfo.GetCustomAttributes(typeof(ActionNameAttribute), false)
    .Cast<ActionNameAttribute>()
    .SingleOrDefault();

// Add to list of routes.
routeParams.Add(new MapRouteParams()
{
    RouteName = routeAttrib.Name,
    Path = routeAttrib.Path,
    ControllerName = controllerName,
    ActionName = (anAttr != null ? anAttr.Name : methodInfo.Name),
    Order = routeAttrib.Order,
    Constraints = GetConstraints(methodInfo),
    Defaults = GetDefaults(methodInfo),
});

Also I found the naming of the route not suitable. The name is built dynamically with controllerName.RouteName. But my route names are const strings in the controller class and I use those const to also call Url.RouteUrl. That's why I really need the route name in the attribute to be the actual name of the route.

Another thing that I will do is to convert the default and constraint attributes to AttributeTargets.Parameter so that I can stick them to params.

Answer 2

1. Download RiaLibrary.Web.dll and reference it in your ASP.NET MVC website project

2. Decoreate controller methods with the [Url] Attributes:

public SiteController : Controller
{
    [Url("")]
    public ActionResult Home()
    {
        return View();
    }

    [Url("about")]
    public ActionResult AboutUs()
    {
        return View();
    }

    [Url("store/{?category}")]
    public ActionResult Products(string category = null)
    {
        return View();
    }
}

BTW, '?' sign in '{?category}' parameter means that it's optional. You won't need to specify this explicitly in route defaults, which is equals to this:

routes.MapRoute("Store", "store/{category}",
new { controller = "Store", action = "Home", category = UrlParameter.Optional });

3. Update Global.asax.cs file

public class MvcApplication : System.Web.HttpApplication
{
    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

        routes.MapRoutes(); // This do the trick
    }

    protected void Application_Start()
    {
        RegisterRoutes(RouteTable.Routes);
    }
}

How to set defaults and constraints? Example:

public SiteController : Controller
{
    [Url("admin/articles/edit/{id}", Constraints = @"id=\d+")]
    public ActionResult ArticlesEdit(int id)
    {
        return View();
    }

    [Url("articles/{category}/{date}_{title}", Constraints =
         "date=(19|20)\d\d-(0[1-9]|1[012])-(0[1-9]|[12][0-9]|3[01])")]
    public ActionResult Article(string category, DateTime date, string title)
    {
        return View();
    }
}

How to set ordering? Example:

[Url("forums/{?category}", Order = 2)]
public ActionResult Threads(string category)
{
    return View();
}

[Url("forums/new", Order = 1)]
public ActionResult NewThread()
{
    return View();
}

Answer 3

I've combined these two approaches into a Frankensteinian version for anybody who wants it. (I liked the optional param notation, but also thought they should be separate attributes from default/constraints rather than all mixed into one).

http://github.com/djMax/AlienForce/tree/master/Utilities/Web/

Answer 4

I needed to get the ITCloud routing working in asp.net mvc 2 using an AsyncController -- to do so, just edit the RouteUtility.cs class in the source and recompile. You have to strip off the "Completed" from the action name on line 98

// Add to list of routes.
routeParams.Add(new MapRouteParams()
{
    RouteName = String.IsNullOrEmpty(routeAttrib.Name) ? null : routeAttrib.Name,
    Path = routeAttrib.Path,
    ControllerName = controllerName,
    ActionName = methodInfo.Name.Replace("Completed", ""),
    Order = routeAttrib.Order,
    Constraints = GetConstraints(methodInfo),
    Defaults = GetDefaults(methodInfo),
    ControllerNamespace = controllerClass.Namespace,
});

Then, in the AsyncController, decorate the XXXXCompleted ActionResult with the familiar UrlRoute and UrlRouteParameterDefault attributes:

[UrlRoute(Path = "ActionName/{title}")]
[UrlRouteParameterDefault(Name = "title", Value = "latest-post")]
public ActionResult ActionNameCompleted(string title)
{
    ...
}

Hope that helps someone with the same issue.