Multiple levels in MVC custom routing

Question

I am trying to build my own little cms. I created an abstract pageBase class that is inherited by Static, Reviews, Articles, News. Each having there own controller methods.

My problem is that I need to allow the admin to define his own custom path levels. E.g. news\local\mynewdog or Articles\events\conventions\mycon. So I would like a way to pass an array of strings and also set the custom routing.

Answer 1

You can make CMS-style routes seamlessly with a custom RouteBase subclass.

public class PageInfo
{
    // VirtualPath should not have a leading slash
    // example: events/conventions/mycon
    public string VirtualPath { get; set; }
    public Guid Id { get; set; }
}

public class CustomPageRoute
    : RouteBase
{
    private object synclock = new object();

    public override RouteData GetRouteData(HttpContextBase httpContext)
    {
        RouteData result = null;

        // Trim the leading slash
        var path = httpContext.Request.Path.Substring(1);

        // Get the page that matches.
        var page = GetPageList(httpContext)
            .Where(x => x.VirtualPath.Equals(path))
            .FirstOrDefault();

        if (page != null)
        {
            result = new RouteData(this, new MvcRouteHandler());

            // Optional - make query string values into route values.
            this.AddQueryStringParametersToRouteData(result, httpContext);

            // TODO: You might want to use the page object (from the database) to
            // get both the controller and action, and possibly even an area.
            // Alternatively, you could create a route for each table and hard-code
            // this information.
            result.Values["controller"] = "CustomPage";
            result.Values["action"] = "Details";

            // This will be the primary key of the database row.
            // It might be an integer or a GUID.
            result.Values["id"] = page.Id;
        }

        // IMPORTANT: Always return null if there is no match.
        // This tells .NET routing to check the next route that is registered.
        return result;
    }

    public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)
    {
        VirtualPathData result = null;

        PageInfo page = null;

        // Get all of the pages from the cache.
        var pages = GetPageList(requestContext.HttpContext);

        if (TryFindMatch(pages, values, out page))
        {
            if (!string.IsNullOrEmpty(page.VirtualPath))
            {
                result = new VirtualPathData(this, page.VirtualPath);
            }
        }

        // IMPORTANT: Always return null if there is no match.
        // This tells .NET routing to check the next route that is registered.
        return result;
    }

    private bool TryFindMatch(IEnumerable<PageInfo> pages, RouteValueDictionary values, out PageInfo page)
    {
        page = null;
        Guid id = Guid.Empty;

        // This example uses a GUID for an id. If it cannot be parsed,
        // we just skip it.
        if (!Guid.TryParse(Convert.ToString(values["id"]), out id))
        {
            return false;
        }

        var controller = Convert.ToString(values["controller"]);
        var action = Convert.ToString(values["action"]);

        // The logic here should be the inverse of the logic in 
        // GetRouteData(). So, we match the same controller, action, and id.
        // If we had additional route values there, we would take them all 
        // into consideration during this step.
        if (action == "Details" && controller == "CustomPage")
        {
            page = pages
                .Where(x => x.Id.Equals(id))
                .FirstOrDefault();
            if (page != null)
            {
                return true;
            }
        }
        return false;
    }

    private void AddQueryStringParametersToRouteData(RouteData routeData, HttpContextBase httpContext)
    {
        var queryString = httpContext.Request.QueryString;
        if (queryString.Keys.Count > 0)
        {
            foreach (var key in queryString.AllKeys)
            {
                routeData.Values[key] = queryString[key];
            }
        }
    }

    private IEnumerable<PageInfo> GetPageList(HttpContextBase httpContext)
    {
        string key = "__CustomPageList";
        var pages = httpContext.Cache[key];
        if (pages == null)
        {
            lock(synclock)
            {
                pages = httpContext.Cache[key];
                if (pages == null)
                {
                    // TODO: Retrieve the list of PageInfo objects from the database here.
                    pages = new List<PageInfo>()
                    {
                        new PageInfo() 
                        { 
                            Id = new Guid("cfea37e8-657a-43ff-b73c-5df191bad7c9"), 
                            VirtualPath = "somecategory/somesubcategory/content1" 
                        },
                        new PageInfo() 
                        { 
                            Id = new Guid("9a19078b-2d7e-4fc6-ae1d-3e76f8be46e5"), 
                            VirtualPath = "somecategory/somesubcategory/content2" 
                        },
                        new PageInfo() 
                        { 
                            Id = new Guid("31d4ea88-aff3-452d-b1c0-fa5e139dcce5"), 
                            VirtualPath = "somecategory/somesubcategory/content3" 
                        }
                    };

                    httpContext.Cache.Insert(
                        key: key, 
                        value: pages, 
                        dependencies: null, 
                        absoluteExpiration: System.Web.Caching.Cache.NoAbsoluteExpiration, 
                        slidingExpiration: TimeSpan.FromMinutes(15), 
                        priority: System.Web.Caching.CacheItemPriority.NotRemovable, 
                        onRemoveCallback: null);
                }
            }
        }

        return (IEnumerable<PageInfo>)pages;
    }
}

You can register the route with MVC like this.

routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

// Case sensitive lowercase URLs are faster. 
// If you want to use case insensitive URLs, you need to
// adjust the matching code in the `Equals` method of the CustomPageRoute.
routes.LowercaseUrls = true;

routes.Add(
    name: "CustomPage", 
    item: new CustomPageRoute());

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

The above assumes you have a CustomPageController with a Details action method.

public class CustomPageController : Controller
{
    public ActionResult Details(Guid id)
    {
        // Do something with id

        return View();
    }
}

You can change the route if you want it to go to a different controller action (or even make them constructor parameters).