MVC

Couple of changes released today, one to Meerkat.Security and the other to Meerkat.Caching.

The first was to introduce handling for grant/deny of actions for unauthenticated users. I’d missed this use case before as to date, the project was just used in a corporate Windows environment and so everyone was authenticated by the time we saw them.

As I’m now working on a project using Azure B2C Active Directory we are now back to the point where users need to authenticate, so you want to filter the actions they can see/perform before and after they authenticate, e.g. you want to allow unauthenticated users access to Home.Index and error pages but probably not much more, and as the principle of the project was to centralize the security checking, we need a way to allow unauthenticated users without using AllowAnonymous on the controller action.

I was working on the design of a small site where we have public display of information in one format and a set of administrative screens that allow authorised users to create and edit the information.

“I know”, I thought, “this is a perfect case for MVC Areas” – and boy was I wrong! I should have realised that the problems had started when all the routing started playing up..

I’ve been using the MvcContrib.TestHelper class for a while now to get rather nice fluent testing of the routes in my MVC applications.

A typical test class would look like this

public class CategoryRoutesFixture : RoutesFixture
{
    private const int categoryId = 34;

    private static string BaseUrl
    {
        get { return "~/admin/Category"; }
    }

    [Test]
    public void Index()
    {
        BaseUrl.ShouldMapTo<CategoryController>(x => x.Index());
    }

    [Test]
    public void Create()
    {
        (BaseUrl + "/create").ShouldMapTo<CategoryController>(x => x.Create());
    }

    [Test]
    public void Show()
    {
        (BaseUrl + "/" + categoryId).ShouldMapTo<CategoryController>(x => x.Show(categoryId));
    }

    [Test]
    public void Edit()
    {
        (BaseUrl + string.Format("/{0}/edit", categoryId)).ShouldMapTo<CategoryController>(x => x.Edit(categoryId));
    }
}

The base class just takes care of initialising the routes collection from the MvcApplication.

Sometimes doing very basic things can be quite tricky in new technologies; case in point presenting a DropDownList (a ComboBox to those, including me, with a VB background) using the new EditorForModel syntax in ASP.NET MVC 2.

I had a little class in my MVP framework called IdLabel which as the name implied just held an Id and a Label so that I wasn’t forced to have a separate display and edit model for every trivial case, so I wanted to do the same sort of thing when writing my shiny new MVC apps. There’s a class called SelectListItem which fits the bill, but unfortunately a decision late in the MVC 2 Beta meant that by default, the object display/edit templates will not process anything other than basic types.

I’m trying to write some templates for MVC 2 and one of the most useful things I’ve found is being able to step into the source code and see how it is actually interpreting what you’ve written.

It’s easy enough to acquire the source, but what you might not have done before is set up a symbol server. A symbol server is a location that the Windows and Visual Studio debugging tools can use to obtain pdb files, so that you can debug almost anything, including drivers and the operating system!