DannyDouglass.com

Application Developer and Technology Enthusiast

What's Nu in the .NET World?

If you thought the word ”Nu” in the title of this blog post was misspelled, you are in for a treat.  And trust me, you are not the only one who made that grammatical assumption.

Nu is an open source tool built by Dru Sellers that aims at bringing Gems, one of Ruby’s most revered features, to the .NET world.  If you are not familiar with Gems I suggest you take a minute to read up on them.  I would venture a bet that you are already familiar with at least one gem – Ruby on Rails.  The following line of code is all that is required to install the Ruby on Rails gem (after installing the Ruby library of course):

gem install rails

Compare that to what is required to install ASP.NET MVC.  Despite having ASP.NET installed, I may need to download a separate installer for a specific version of Visual Studio.  Semantics aside, it is just plain more difficult. That is not to say installing ASP.NET MVC is overly complex, nor am I attempting to disrespect the ASP.NET MVC framework.  I’m actually a big fan of ASP.NET MVC. My intention is to show that the gem installation is just crazy simple and a piece of the programmatic puzzle missing in .NET development.  Many, including myself, are hoping that Nu proves to be the solution to this shortcoming.

This is not the first time someone has attempted to solve the “Missing Gem” (as I have decided to label it) mystery in the .NET world.  I recall my friend Troy Goode discussing this exact problem with Stephen Walther just prior to him joining Microsoft way back in early 2008.  Many others have tried to replace Ruby Gems in the .NET world, but none have been successful.  Dru Sellers decided to take a different approach and leverage the existing Ruby Gems tools and expand upon it to bring gems to .NET.  Brilliant.

Enough discussion about Nu – I will let the code speak for itself.  In the following example I will create a basic ASP.NET MVC 2 web application (.NET 4.0) and use the Nu package installer to hook in AutoFac, a .NET IoC container.  Do not be alarmed if you do not know what AutoFac or IoC are at this point.  Just understand that I have an external component that I would like to utilize in my project.  For a list of all the currently available Nu packages you can take a look at the Current .NET Nu Packages page on the Nu wiki.  Now let’s see the code!

Note: You must install Ruby as a prerequisite to using Nu since it leverages Ruby’s Gem tool.

The first step is to create a new ASP.NET MVC 2 application:

image)

Once the application is created I can quickly run it and see the screen that anyone who has read about or used ASP.NET MVC before is very familiar with:

image

Now that I have my project created I want to download the AutoFac library and bring it into my project.  Prior to Nu, I would do this by opening a browser, finding the AutoFac download page, download, possibly unzip the files, etc. Nu makes this much simpler.  First thing I want to do install Nu using the Ruby gem tool by simply executing the command gem install nu.

NuGemInstall

Once I have installed Nu, I can easily download the AutoFac gem by executing the command nu install autofac.

image

Note that by default Nu will install your gems local (in a new lib directory) to the folder where you execute the nu install #somegem# command.  Taking a look at my c:\projects\Nu_AspNetMvc2_Demo directory I can see that two folders were created: .nu and lib.  The lib folder will hold all of the gems I install in this directory from here on out, unless I override the default at a later time.  I will not go into further details, but my AutoFac dlls are now stored inside of my /lib/autofac package directory.You can take a look at the example’s source to see more about the package directory structure.

NuAutofacInstallFolders

Currently Nu is in its early stages and I am still required to add the DLLs to my project manually, but very soon this will not be the case.  A Nu for Visual Studio plugin is in the works that will simplify this step – take a look at this video preview to see it in action.  I imagine there will be other ways to accomplish this as well.  For now, I will simply add the required references as I would with any other library I downloaded to my Visual Studio Project:

ProjectReferences

Now all I need to do is follow these instructions to hookup AutoFac 2 in my global.asax.cs (code shown below) and I am good to go! Running my project shows me that same familiar MVC homepage, however this time my controller factory is running using the AutoFac controller factory (see line 33 below):

using System.Reflection;
using System.Web;
using System.Web.Mvc;
using System.Web.Routing;
using Autofac;
using Autofac.Integration.Web;
using Autofac.Integration.Web.Mvc;  
namespace Nu_AspNetMvc2_Demo
{
    public class MvcApplication : HttpApplication, IContainerProviderAccessor
    {
        private static IContainerProvider _containerProvider;  
        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");  
            routes.MapRoute(
                "Default", // Route name
                "{controller}/{action}/{id}", // URL with parameters
                new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
            );  
        }  
        protected void Application_Start()
        {
            var builder = new ContainerBuilder();
            builder.RegisterControllers(Assembly.GetExecutingAssembly());

            _containerProvider = new ContainerProvider(builder.Build());
            ControllerBuilder.Current.SetControllerFactory(new AutofacControllerFactory(ContainerProvider));  
            AreaRegistration.RegisterAllAreas();
            RegisterRoutes(RouteTable.Routes);
        }  
        public IContainerProvider ContainerProvider
        {
            get { return _containerProvider; }
        }
    }
}

As you can see there is a lot of power in using Nu.  There are many other areas I could have gone into further detail, but I wanted this to be a simple introduction to the power of Nu packages.  I plan on following up with additional posts to show other features of Nu and maybe even a post on creating your very own Gem.  In the meantime I want to include a few resources to help you learn more about Nu:

  1. Nu Wiki | http://nu.wikispot.org

  2. Nu Google Group | http://groups.google.com/group/nu-net

  3. The Power of Nu Video | http://www.youtube.com/watch?v=IvxAa4XURss&feature=youtu.be

Download this Example’s Source Code

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