ASP.NET MVC: Routing custom slugs without affecting performance

Question

I would like to create custom slugs for pages in my CMS, so users can create their own SEO-urls (like Wordpress).

I used to do this in Ruby on Rails and PHP framewor

Answer 1

Even if your route registration code works as is, the problem will be that the routes are registered statically only on startup. What happens when a new post is added - would you have to restart the app pool?

You could register a route that contains the SEO slug part of your URL, and then use the slug in a lookup.

RouteConfig.cs

routes.MapRoute(
    name: "SeoSlugPageLookup",
    url: "Page/{slug}",
    defaults: new { controller = "Page", 
                    action = "SlugLookup",
                  });

PageController.cs

public ActionResult SlugLookup (string slug)
{
    // TODO: Check for null/empty slug here.

    int? id = GetPageId (slug);

    if (id != null) {    
        return View ("Show", new { id });
    }

    // TODO: The fallback should help the user by searching your site for the slug.
    throw new HttpException (404, "NotFound");
}

private int? GetPageId (string slug)
{
    int? id = GetPageIdFromCache (slug);

    if (id == null) {
        id = GetPageIdFromDatabase (slug);

        if (id != null) {
            SetPageIdInCache (slug, id);
        }
    }

    return id;
}

private int? GetPageIdFromCache (string slug)
{
    // There are many caching techniques for example:
    // http://msdn.microsoft.com/en-us/library/dd287191.aspx
    // http://alandjackson.wordpress.com/2012/04/17/key-based-cache-in-mvc3-5/
    // Depending on how advanced you want your CMS to be,
    // caching could be done in a service layer.
    return slugToPageIdCache.ContainsKey (slug) ? slugToPageIdCache [slug] : null;
}

private int? SetPageIdInCache (string slug, int id)
{
    return slugToPageIdCache.GetOrAdd (slug, id);
}

private int? GetPageIdFromDatabase (string slug)
{
    using (CMSContext db = new CMSContext()) {
        // Assumes unique slugs.
        Page page = db.Pages.Where (p => p.Slug == requestContext.Url).SingleOrDefault ();

        if (page != null) {
            return page.Id;
        }
    }

    return null;
}

public ActionResult Show (int id)
{
    // Your existing implementation.
}

(FYI: Code not compiled nor tested - haven't got my dev environment available right now. Treat it as pseudocode ;)

This implementation will have one search for the slug per server restart. You could also pre-populate the key-value slug-to-id cache at startup, so all existing page lookups will be cheap.

Answer 2

I've edited my answer to give a more complete answer to your questions:

Answer to Question 1:

Registering routes is initialized on startup. (Perhaps also when the Application Pool recycles, it's highly probable.) I also think there is nothing wrong with your approach since it is occuring only once. I do the same thing querying all supported languages from the database to register them as /TwoLetterISOLanguageName (/nl, /en, /de, etc.).

Answer to Question 2:

This should work passing a model: Put it before the Default route!

routes.MapRoute(
    name: "Contact",
    url: "contact/{action}",
    defaults: new { controller = "Contact", 
                    action = "Index",
                    MyModel = new MyModel { Name = "hello" } });

The ContactController:

public ActionResult Index(MyModel mymodel)
{
    return Content(mymodel.Name);
}

The Model:

public class MyModel
{
    public string Name { get; set; }
}