How can I have lowercase routes in ASP.NET MVC?

Question

With System.Web.Routing 4.5 you may implement this straightforward by setting LowercaseUrls property of RouteCollection:

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

        routes.LowercaseUrls = true;

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

Also assuming you are doing this for SEO reasons you want to redirect incoming urls to lowercase (as said in many of the links off this article).

protected void Application_BeginRequest(object sender, EventArgs e)
    {
        //You don't want to redirect on posts, or images/css/js
        bool isGet = HttpContext.Current.Request.RequestType.ToLowerInvariant().Contains("get");
        if (isGet && !HttpContext.Current.Request.Url.AbsolutePath.Contains("."))
        {
            //You don't want to modify URL encoded chars (ex.: %C3%8D that's code to Í accented I) to lowercase, than you need do decode the URL
            string urlLowercase = Request.Url.Scheme + "://" + HttpUtility.UrlDecode(HttpContext.Current.Request.Url.Authority + HttpContext.Current.Request.Url.AbsolutePath);
            //You want to consider accented chars in uppercase check
            if (Regex.IsMatch(urlLowercase, @"[A-Z]") || Regex.IsMatch(urlLowercase, @"[ÀÈÌÒÙÁÉÍÓÚÂÊÎÔÛÃÕÄËÏÖÜÝÑ]"))
            {
                //You don't want to change casing on query strings
                urlLowercase = urlLowercase.ToLower() + HttpContext.Current.Request.Url.Query;

                Response.Clear();
                Response.Status = "301 Moved Permanently";
                Response.AddHeader("Location", urlLowercase);
                Response.End();
            }
        }
    }

These two tutorials helped when I wanted to do the same thing and work well:

http://www.coderjournal.com/2008/03/force-mvc-route-url-lowercase/ http://goneale.com/2008/12/19/lowercase-route-urls-in-aspnet-mvc/

EDIT: For projects with areas, you need to modify the GetVirtualPath() method:

public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)
{
  var lowerCaseValues = new RouteValueDictionary();

  foreach (var v in values)
  {
    switch (v.Key.ToUpperInvariant())
    {
      case "ACTION":
      case "AREA":
      case "CONTROLLER":
        lowerCaseValues.Add(v.Key, ((string)v.Value).ToLowerInvariant());
        break;
      default:
        lowerCaseValues.Add(v.Key.ToLowerInvariant(), v.Value);
        break;
    }
  }
  return base.GetVirtualPath(requestContext, lowerCaseValues);
}

If you happened to use ASP.NET Core, you probably should have a look at this:

Add the following line to the ConfigureServices method of the Startup class.

services.AddRouting(options => options.LowercaseUrls = true);

If you are using the UrlHelper to generate the link, you can simply specify the name of the action and controller as lowercase:

itemDelete.NavigateUrl = Url.Action("delete", "photos", new { key = item.Key });

Results in: /media/photos/delete/64 (even though my controller and action are pascal case).

I found this at Nick Berardi’s Coder Journal, but it did not have information on how to implement the LowercaseRoute class. Hence reposting here with additional information.

First extend the Route class to LowercaseRoute

public class LowercaseRoute : Route
{
    public LowercaseRoute(string url, IRouteHandler routeHandler)
        : base(url, routeHandler) { }
    public LowercaseRoute(string url, RouteValueDictionary defaults, IRouteHandler routeHandler)
        : base(url, defaults, routeHandler) { }
    public LowercaseRoute(string url, RouteValueDictionary defaults, RouteValueDictionary constraints, IRouteHandler routeHandler)
        : base(url, defaults, constraints, routeHandler) { }
    public LowercaseRoute(string url, RouteValueDictionary defaults, RouteValueDictionary constraints, RouteValueDictionary dataTokens, IRouteHandler routeHandler) : base(url, defaults, constraints, dataTokens, routeHandler) { }
    public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)
    {
        VirtualPathData path = base.GetVirtualPath(requestContext, values);

        if (path != null)
            path.VirtualPath = path.VirtualPath.ToLowerInvariant();

        return path;
    }
}

Then modify the RegisterRoutes method of Global.asax.cs

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

    routes.Add(new LowercaseRoute("{controller}/{action}/{id}", 
        new RouteValueDictionary(new { controller = "Home", action = "Index", id = "" }), 
        new MvcRouteHandler()));

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

I would however like to know a way to use routes.MapRoute...