Griffin.MvcContrib – The plugin system


Griffin.MvcContrib is a contribution project for ASP.NET MVC3 which contains different features like extendable HTML Helpers (you can modify the HTML that the existing helpers generate), easy localization support and a quite fresh support for plugin development. The purpose of this article is to provide a step-by-step instruction on how you can develop plugins using Griffin.MvcContrib.

Using the code

The plugin support are based on the Area support which MVC3 got. If you haven’t used areas before, I suggest that you start by reading the following article.

Most basic approach.

This first sample is not really a plugin system but only showing how you can move your code to class libraries. The example will only contain one class library to avoid confusion.
Start by creating a new ASP.NET MVC3 project (of any kind) and a class library project. For convenience we would like to have support for Razor and all MVC3 wizards in our class library. It helps us add some basic files which are required to get everything working.
To get that support we need to modify the project file for the class library. Here is how:

1. Right-click on the class library project and choose unload project:

2. Right-click on the project file and select Edit project file

3. Add the following XML element on a new line below <ProjectGuid>


4. Save and close the project file.

5. Right-click and reload the project.

6. Add reference to “System.Web” and “System.Web.Mvc” (project settings)

You have now told Visual Studio that it should active the tooling and Razor 3 views. We can now add an area by just right-clicking on the project and select “Add Area”.

Do so and create an area with a name of your choosing. Create a controller (with an Index action) and a view for the index action. You now got your first external DLL for the MVC project.

Add a reference to the class library from the MVC3 project:

Congratulations. You now got your first “plugin” based solution. Hit F5 to run the project. I named my area “Ohh” and my controller “My” so I surf to “http://theHostNameAndPort/ohh/my” to visit my plugin controller.

Uh oh. We can visit the page alright. But the view cannot be found. It can be solved thanks to Griffin.MvcContrib. Let’s install the project in the MVC3 project:

Then open up global.asax and create a new method which maps the views:

protected void Application_Start()
protected void RegisterViews()
    var embeddedProvider = new EmbeddedViewFileProvider(HostingEnvironment.MapPath("~/"), new ExternalViewFixer());
    embeddedProvider.Add(new NamespaceMapping(typeof(Lib.Areas.Some.Controllers.MyController).Assembly, "BasicPlugins.Lib"));

The first line creates a new file provider which loads files from embedded resources. We tell it which path it should try to provide files for. The next line simply adds our class library assembly and tell which root namespace it has. To make this work, we also have to change our view to an embedded resource:

Everything should be set now. Hit F5 and visit the area controller again. You should see the view now.

You can also try to have a break point in the class library. Debugging should work just like it used to. There is still one “problem”. We can’t modify the views at runtime, we need to recompile the project each time we adjust a view. Fortunually for us, Griffin.MvcContrib can solve that too. Open the RegisterViews method in global.asax again. Let’s add a disk file provider. It should be added before the embedded provider since the first found file will be used.

var diskLocator = new DiskFileLocator();
diskLocator.Add("~/", Path.GetFullPath(Server.MapPath("~/") + @"..BasicPlugins.Lib"));
var viewProvider = new ViewFileProvider(diskLocator);

You can now edit the views at runtime.

Building a plugin system

The last part showed you how you can put Controllers, Models and Views in class libraries. It’s quite useful as long as you don’t want to develop features in a more loosely coupled and dynamic way. This section will suggest a structure which you can use when building plugins.

The following part expects you to have used inversion of control containers in the past. The container is used to provide the application extension points to all plugins. I prefer using a container which has a module system so that each plugin can take care of all it’s registrations itself. I’m using Autofac in this article and it’s Module extension.

Let’s place all code which is shared between the plugins and the MVC3 project in a seperate class library. You could also follow follow the Separated interface pattern and only define all interfaces in that project. Thus removing all direct dependencies between the plugins and the main application.

The last thing to remember is that the default route configuration doesn’t work very well if you have controllers with the same name in different areas. To overcome that you have to manually change all route mappings to include the namespace. Also remove the “_default” from the route name.

Modified registration:

public override void RegisterArea(AreaRegistrationContext context)
		new { action = "Index", id = UrlParameter.Optional },
		new[] { GetType().Namespace + ".Controllers" }

Create a new class library named something like “YourApp.PluginBase” and add our basic extension points:

public interface IRouteRegistrar
	void Register(RouteTable routes);

Used to register any custom routes.

public interface IMenuRegistrar
	void Register(IMenuWithChildren mainMenu);

Allows the plugins to register themselves in the main application menu.

We’ll just use those two extensions in this example. Feel free to add as many extensions as you like in your own project ;)

The structure

We’ll need to have some structure for the plugins so that the can easily be managed, both during development and in production. All plugins will therefore be placed in a sub directory called “Plugins”. Something like:


Add a new solution folder by right-clicking on the solution folder in the Solution Explorer. Do note that solution folders doesn’t exist on the disk and you’ll therefore have to manually append the folder to the location text box each time you add a new project in it.

Right-click on the Plugins folder in Solution Explorer and add a new project named “PluginName”. Don’t forget to append PluginsPlugin.Name to the location text box.

Since we this time don’t want to have any references to the plugins from the main application we have to manually copy them to the main application plugin folder. We use a post build event for that. Don’t forget to copy in all dependencies that your project has, since nothing handles that for you (the price of having no direct references from the MVC3 project to the plugins).

Complete structure:

Menu items

Keep in mind that you can not unload plugins and that they are available for all users. The easiest way to come around that is to display menu items only if the user has a role, which means that you should create one (or more) role(s) per plugin (if the plugin should not be available for all users). Griffin.MvcContrib contains a basic menu implementation which allows you to control if menu items are visible or not.

Sample code:

var item = new RouteMenuItem("mnuMyPluginIndex", "List messages", new { 
        controller = "Home", 
        action = "Index", 
        area = "Messages"});
item.Role = "MessageViewer";

You can later use menuItem.IsVisible when you generate the menu to determine if the item should be included or not.

Hello container

For this exercise we’ll use Autofac as the container. It contains a nifty module system which aids us in keeping the projects loosely coupled. Each plugin need to create a class which inherits from Autofac.Module and use that class to register all services which the plugin provides. Thanks to that we’ll just have to scan all plugin assemblies after any container modules and invoke them with our container.

public class ContainerModule : Module
	protected override void Load(ContainerBuilder builder)

The plugins are loaded from the main application using the following snippet:

var moduleType = typeof (IModule);
var modules = plugin.GetTypes().Where(moduleType.IsAssignableFrom);
foreach (var module in modules)
	var mod = (IModule) Activator.CreateInstance(module);

Views during development

Since we want to be able to modify views at runtime during development we have to tell ASP.NET MVC3 where it can find our plugin views. We do this by using GriffinVirtualPathProvider and a custom file locator which looks like this:

public class PluginFileLocator : IViewFileLocator
    public PluginFileLocator()
        _basePath = Path.GetFullPath(HostingEnvironment.MapPath("~") + @"..Plugins");

    public string GetFullPath(string uri)
        var fixedUri = uri;
        if (fixedUri.StartsWith("~"))
            fixedUri = VirtualPathUtility.ToAbsolute(uri);
        if (!fixedUri.StartsWith("/Areas", StringComparison.OrdinalIgnoreCase))
            return null;

        // extract area name:
        var pos = fixedUri.IndexOf('/', 7);
        if (pos == -1)
            return null;
        var areaName = fixedUri.Substring(7, pos - 7);

        var path = string.Format("{0}{1}\Plugin.{1}{2}", _basePath, areaName, fixedUri.Replace('/', '\'));
        return File.Exists(path) ? path : null;

It simply takes the requested uri and converts it using the naming standard I described above. Everything else is taken care of by Griffin.MvcContrib.

And interesting part is that the provider is only loaded during development thanks to nifty helper class in Griffin.MvcContrib:

if (VisualStudioHelper.IsInVisualStudio)

Loading the plugins

Ok. We’ve created some plugins (and their dependencies) which are copied to the bin folder with a post build event. We’ll therefore have to load them in some way. To do this we create a new class looking like this:

public class PluginService
    private static PluginFinder _finder;
    private readonly DiskFileLocator _diskFileLocator = new DiskFileLocator();
    private readonly EmbeddedViewFileProvider _embededProvider =
        new EmbeddedViewFileProvider(new ExternalViewFixer());
    private readonly PluginFileLocator _fileLocator = new PluginFileLocator();
    private readonly ViewFileProvider _diskFileProvider;

    public PluginService()
        _diskFileProvider = new ViewFileProvider(_fileLocator, new ExternalViewFixer());

        if (VisualStudioHelper.IsInVisualStudio)


    public static void PreScan()
        _finder = new PluginFinder("~/bin/");

    public void Startup(ContainerBuilder builder)
        foreach (var assembly in _finder.Assemblies)
            // Views handling
            _embededProvider.Add(new NamespaceMapping(assembly, Path.GetFileNameWithoutExtension(assembly.Location)));
                                 Path.GetFullPath(HostingEnvironment.MapPath("~/") + @"...." +

            //Autofac integration
            var moduleType = typeof (IModule);
            var modules = assembly.GetTypes().Where(moduleType.IsAssignableFrom);
            foreach (var module in modules)
                var mod = (IModule) Activator.CreateInstance(module);

    // invoke extension points
    public void Integrate(IContainer container)
        foreach (var registrar in container.Resolve<IEnumerable<IMenuRegistrar>>())

        foreach (var registrar in container.Resolve<IEnumerable<IRouteRegistrar>>())

The plugins are now loaded and the extension points have been passed to them.

Final touch

The last thing to change is global.asax:

protected void Application_Start()


    _pluginServicee = new PluginService();

private void RegisterContainer()
    var builder = new ContainerBuilder();
    _container = builder.Build();
    DependencyResolver.SetResolver(new AutofacDependencyResolver(_container));


The code for the samples are located in github and so is Griffin.MvcContrib. Griffin.MvcContrib can also be install from nuget.

griffin.editor: Added support for Google Prettify

I’ve just refactored the highlighting features of griffin.editor. You can now use your favorite highlighter by implementing the $.griffinEditorExtension.highlighter callback like this:

$.griffinEditorExtension.highlighter = function(inlineSelector, blockSelector) {
    $.each(blockSelector, funtion() {
        console.log('Code block to highlight: ' + $(this).html());

The default implementation looks for either highlight.js or Google Prettify.

I’ve also made a small change so that the inline code blocks aren’t highlighted per default. It makes the text more readable imho (and the programming language guessing in the highlights have too little code to guess on).

A javascript selection script

I wanted a lightweight and cross browser plugin to be able to handle selections in a text area (for my griffin.editor plugin). Didn’t find a suitable one despite asking at I created my own. It’s stand alone and only 2,6kb (uncompressed).


//jQuery is not required but supported.
var selection = new TextSelector($('#mytextarea'));
selection.replace('New text');

// you can change selection:,10); // select char 1 to 10

// get selection information
console.log("Start char: " + selection.get().start);

// check if anything is selected

// get the text
var text = selection.text();

Code at github

Introducing griffin.editor – a jQuery textarea plugin

I’ve tried to find a jQuery editor plugin which works out of the box without configuration. The WMD editor used by looked nice but I couldn’t find a version that I got running. My main issue with most editors was that I didn’t figure out how to configure custom image and link dialogs. I’ve therefore done my own.


  • Markdown (currently the only format supported)
  • Preview pane (see generated HTML live)
  • Syntax highlighting (live), using highlightjs or google prettify
  • Expanding textarea (which also goes back to original size on blur)
  • jQueryUI dialogs for links/images
  • Access keys (default browser modifier or CTRL if activated)
  • Plug & Play (just include additional scripts to activate features)

The basic setup looks like this:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "">
  <title>Editor demo</title>
  <script type="text/javascript" src="scripts/jquery-1.6.2.min.js"></script>
  <script type="text/javascript" src="scripts/jquery.markdown-0.2.js"></script>
  <script type="text/javascript" src="../Source/textselector.js"></script>
  <script type="text/javascript" src="../Source/jquery.griffin.editor.js"></script>
  <script type="text/javascript" src="../Source/jquery.griffin.editor.markdown.js"></script>
  <style type="text/css">
   .editor .area { width: 600px; height: 200px; }
   .editor .toolbar { padding: 0px;  }
<div class="editor">
	<div class="toolbar">
		<span class="button-h1" accesskey="1" title="Heading 1"><img src="../Source/images/h1.png" /></span>
		<span class="button-h2" accesskey="2" title="Heading 2"><img src="../Source/images/h2.png" /></span>
		<span class="button-h3" accesskey="3" title="Heading 3"><img src="../Source/images/h3.png" /></span>
		<span class="button-bold" accesskey="b" title="Bold text"><img src="../Source/images/bold.png" /></span>
		<span class="button-italic" accesskey="i" title="Italic text"><img src="../Source/images/italic.png" /></span>
		<span class="divider">&nbsp;</span>
		<span class="button-bullets" accesskey="l" title="Bullet List"><img src="../Source/images/bullets.png" /></span>
		<span class="button-numbers" accesskey="n" title="Ordered list"><img src="../Source/images/numbers.png" /></span>
		<span class="divider">&nbsp;</span>
		<span class="button-sourcecode" accesskey="k" title="Source code"><img src="../Source/images/source_code.png" /></span>
		<span class="button-quote" accesskey="q" title="Qoutation"><img src="../Source/images/document_quote.png" /></span>
		<span class="divider">&nbsp;</span>
		<span class="button-link" accesskey="l" title="Insert link"><img src="../Source/images/link.png" /></span>
		<span class="button-image" accesskey="p" title="Insert picture/image"><img src="../Source/images/picture.png" /></span>
	<textarea class="area">Hello world</textarea>
<script type="text/javascript">

All of that is required. (Just a simple copy/paste). The idea is that you should easily be able to customize it’s layout. The script generates the following layout:

Basic layout


The basic setup uses browser dialog boxes:

Dialog box

Not so sexy. Include jQueryUI and the integration script:

  <link rel="stylesheet" href="Styles/jquery-ui-1.8.16.custom.css">
  <script type="text/javascript" src="scripts/jquery-ui-1.8.16.custom.min.js"></script>
  <script type="text/javascript" src="../Source/jquery.griffin.editor.dialogs.jqueryui.js"></script>

.. to automatically reconfigure the plugin to use jQueryUI:

Using jQueryUI for dialogs

You can use your own dialogs by implementation the following function:

$.griffinEditorExtension.imageDialog = function(options)
    //options.title & options.url contains info specified in the editor

   // invoke when done
   options.success({ title: 'Some title', url: 'Some url';}) when you are done

Same goes for the link dialog.

Preview pane

The preview pane is automatically configured when you add a div with a special id:

<div class="editor" id="myeditor">
//all the editor code
<div id="myeditor-preview">

This allows you to place the preview pane wherever you like. The included demo scripts places the preview to the right:

Preview pane

You can also add support for syntax highlighting by including additional script & stylesheet:

  <script src=""></script>
  <link rel="stylesheet" href="">

The script inclusion will activate those features, no additional configuration is required.

Access keys

The default access key implementation uses the browser specific implementation. For instance Win+Chrome uses ALT+Key to activate it. Hence no additional information in the tooltip:

Default access keys

That can be changed by adding a hotkeys script:

  <script type="text/javascript" src="scripts/jquery.hotkeys.js"></script>

Which reconfigures the tooltips and allows you to use CTRL+key to access the toolbar features. The key is still controlled by the accesskey attribute on the toolbar icons.

Better hotkeys


The codez & all examples are available at github.

Generic repositories – A silly abstraction layer

This post is all about GENERIC repositories as in Repository, not about all types of repositories. Repositories are a great way to abstract away the data source. Doing so makes your code testable and flexible for future additions.

My recommendation is against generic repositories, since they don’t give you any additional value compared to regular repository classes. “Regular” repositories are usually written specifically for the requirements that your project have.

Let’s look at what generic repositories give you:

You can change OR/M implementation at any time.


  1. If you find yourself having switch OR/M during a project you have not done you homework before you started the project.
  2. The OR/M choice doesn’t matter since you have abstracted away the features of the chosen OR/M

imho you’ll stick with one OR/M during a project and switch for the next one (if you have to switch).

You have to write less code.

Here is a Generic repository (nhibernate implementation) from a SO question:

public interface IRepository<T> : IQueryable<T>
  void Add(T entity);
  T Get(Guid id);
  void Remove(T entity);

public class Repository<T> : IQueryable<T>
  private readonly ISession session;

  public Repository(ISession session)
    session = session;

  public Type ElementType
    get { return session.Query<T>().ElementType; }

  public Expression Expression
    get { return session.Query<T>().Expression; }

  public IQueryProvider Provider
    get { return session.Query<T>().Provider; } 

  public void Add(T entity)

  public T Get(Guid id)
    return session.Get<T>(id);

  IEnumerator IEnumerable.GetEnumerator()
    return this.GetEnumerator();

  public IEnumerator<T> GetEnumerator()
    return session.Query<T>().GetEnumerator();

  public void Remove(T entity)

Take a look at the methods. All they do is to call methods in nhibernate. You do not win anything by doing so. All you get is an abstraction layer that removes the good things with nhibernate/ef/whatever.

It’s better to create a proper base class and move all repeated (DRY) functionality into it (and therefore still be able to take advantage of the features in your favorite OR/M).


Did I miss something that a generic repository gives you? Please make a comment.

Repositories, Unit Of Work and ASP.NET MVC

There are a lot of posts discussing repository implementations, unit of work and ASP.NET MVC. This post is an attempt to give you and answer which addresses all three issues.


Do NOT create generic repositories. They look fine when you look at them. But as the application grow you’ll notice that you have to do some workarounds in them which will break open/closed principle.

It’s much better to create repositories that are specific for an entity and it’s aggregate since it’s much easier to show intent. And you’ll also only create methods that you really need, YAGNI.

Generic repositories also removes the whole idea with choosing an OR/M since you can’t use your favorite OR/Ms features.

Unit Of Work

Most OR/Ms available do already implement the UoW pattern. You simply just need to create an interface and make and adapter (google Adapter pattern) implementation for your OR/M.


    public interface IUnitOfWork : IDisposable
        void SaveChanges();

NHibernate sample implemenetation:

    public class NHibernateUnitOfWork : IUnitOfWork
        private readonly ITransaction _transaction;

        public NHibernateUnitOfWork(ISession session)
            if (session == null) throw new ArgumentNullException("session");
            _transaction = session.BeginTransaction();

        public void Dispose()
            if (!_transaction.WasCommitted)


        public void SaveChanges()


I prefer to use an attribute to handle transactions in MVC. It makes the action methods cleaner:

[HttpPost, Transactional]
public ActionResult Update(YourModel model)
    //your logic here

And the attribute implementation:

public class TransactionalAttribute : ActionFilterAttribute
    private IUnitOfWork _unitOfWork;

    public override void OnActionExecuting(ActionExecutingContext filterContext)
        _unitOfWork = DependencyResolver.Current.GetService<IUnitOfWork>();


    public override void OnActionExecuted(ActionExecutedContext filterContext)
        // let the container dispose/rollback the UoW.
        if (filterContext.Exception == null)


Localizing jQuery plugins

I’ve spent some time to figure out how to localize my jQuery plugins and I’ve just found out a way that works just fine. Disclaimer: I’m not 100% sure of how namespacing works in jQuery so this might not be the correct way.

I’m using the meta header accept-language to control which language to use. It allows me to select the language in my backend (using user settings or whatever) instead of just using the languages defined by the browser. An ASP.NET MVC3 header would look like this in the layout:

<meta name="accept-language" content="@System.Globalization.CultureInfo.CurrentCulture.Name" />

You should be able to do the same thing in PHP or whatever language you use.

Next thing to do is to add the localization structure to your plugin script file:

(function($) {
    $.yourPluginName = {
        texts: {
            title: 'Please wait, loading..'
        translations: []
    var methods = {
		// your methods here.

    $.fn.yourPluginName = function(method) {

        if (methods[method]) {
            return methods[method].apply(this,, 1));
        } else if (typeof method === 'object' || !method) {
            return methods.init.apply(this, arguments);
        } else {
            $.error('Method ' + method + ' does not exist on jQuery.yourPluginName');



That will make the plugin work if no languages are loaded. The translations will be loaded into the $.yourPluginName.translations array by another script.

We got one thing left to do before we can use the texts in your script. We need to load the correct language. Create another script called jquery.yourpluginnamne.localization.js and load it after$.yourPluginName.texts.anyTextName in your plugin to use the localized strings.

Get an unique session in each browser tab

I got a lot to do at work, hence the silence. I got a lot to blog about, but so little time ;/ I found an interesting question at stackoverflow which this answer is for (also to show you that the blog is not forgotten).

A user wanted to store browser tab specific data which can be a problem since most browsers shares a session between different tabs. The solution is to create a new route which generates a GUID and then
use that guid to fetch and store session information. Keep in mind that you need to routes: One that works for users which just surfed into the site, and one that loads an existing guid.

Here is the route class:

public class GuidRoute : Route
	private readonly bool _isGuidRoute;

	public GuidRoute(string uri, object defaults)
		: base(uri, new RouteValueDictionary(defaults), new MvcRouteHandler())
		_isGuidRoute = uri.Contains("guid");

		DataTokens = new RouteValueDictionary();

	public override RouteData GetRouteData(HttpContextBase httpContext)
		var routeData = base.GetRouteData(httpContext);
		if (routeData == null)
			return null;

		if (!routeData.Values.ContainsKey("guid") || routeData.Values["guid"].ToString() == "")
			routeData.Values["guid"] = Guid.NewGuid().ToString("N");

		return routeData;

	public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)
		return !_isGuidRoute ? null : base.GetVirtualPath(requestContext, values);

Replace the default route in global.asax with it:

	"Default", // Route name
	"{controller}/{action}/{id}", // URL with parameters
	new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults

routes.Add("Default", new GuidRoute(
	new { controller = "Home", action = "Index", guid = "", id = UrlParameter.Optional }));

routes.Add("GuidRoute", new GuidRoute(
	new { controller = "Home", action = "Index", guid = "", id = UrlParameter.Optional }));

And finally some extension methods to make life easier in the controllers:

public static class ControllerExtensionMethods
	public static string GetGuid(this Controller controller)
		return controller.RouteData.Values["guid"].ToString();

	public static void SetGuidSession(this Controller controller, string name, object value)
		controller.Session[controller.GetGuid() + "_" + name] = value;

	public static object GetGuidSession(this Controller controller, string name)
		return controller.Session[controller.GetGuid() + "_" + name];

One thing left though: Any browser bookmarks will use an old GUID. Should not be a problem in most cases (unless the user opens the bookmark in multiple tabs = sharing the session between the tabs). Same
thing goes for opening a link in a new tab = shared.

Introducing my logging library

I’ve just published the first version (consider it a beta) of my logging library to the official nuget server(s).

Why another library when there are existing ones as log4net and nlog? Because it should be easier to get started and you should still have the power to customize the logging if needed. Griffin.Logging do not have a configuration file, everything is configured through code.

Simple syntax

The easiest approach only requires one line to configure the framework:


You can swap the AddFile method to AddConsole if you would like.

Fluent syntax

Use the fluent syntax if you need more power:

var config = new FluentConfiguration()
	  .As.ConsoleLogger().Filter.OnLogLevelBetween(LogLevel.Info, LogLevel.Error)


public class MyClass
    ILogger logger = LogManager.GetLogger<MyClass>();

    public MyClass()
        // Built in formatting for cleaner syntax.
        logger.Info("Welcome {0}!.", user.Name);
    public void HideError()
            throw new InvalidOperationException("No no", new OutOfScopeException("Can't thing anymore"));
        catch (Exception err)
            // Log an exception. The inner exceptions are logged too (recursive)
            logger.Warning("Ooops, we got an exception.", ex);



Check the homepage for more information or just install the nuget package “griffin.logging“.