HTTP Services With WCF 4 and Windsor

Although a bit old, I found the following article, Vanilla Yet Composable HTTP Services With WCF 4 and Windsor, extremely helpful.

The article shows how to easily create services, and have their dependencies automatically resolved by the Windsor container, with minimal changes.

Windsor: Loading installers from the execution folder

When using Windsor, it is necessary to load the various IWindowsInstallers into the container. One standard way of doing this is using a code similar to the below:

container.Install(FromAssembly.InDirectory(new AssemblyFilter(".")));

The above code will load all the installed that are located in the execution folder.

However, in certain cases, when your code is running in different contexts, such as under IIS, you need to be a bit more explicit about things. You need to tell Windsor to load assemblies from the folder where you are running, and not from some run-time "copy" or cache folder.

For that, you can use the following class:

public class ExecutingAssemblyFilter : AssemblyFilter
{
    public ExecutingAssemblyFilter()
        : base(new FileInfo(new Uri(Assembly.GetExecutingAssembly).CodeBase).LocalPath).Directory.ToString())
    { }
 }

This class inherits from AssemblyFilter, and automatically provides the correct path. It should be used like this:

container.Install(FromAssembly.InDirectory(new ExecutingAssemblyFilter()));

Windsor Factories and Obfuscation

I love Windsor - it's simplicity yet versatility amazes me every time I use it.

In my last project, I've used it, along with the TypedFactoryFacility in order to "late-resolve" some objects. The resolved object required some parameters to be passed to the CTOR - nothing too complex - you just create an annonymous type with properties that match the names of the parameters, and Windsor handles the matching and passes the values. Piece of cake.

Everything worked perfectly fine for a while. That is, until we started to test our release setups. Our testing team started to complain that the UI is not updated when they click the various buttons.
After some digging, I figured that objects are not being created in the Business Logic layer that uses Windsor, which are then reflected in the UI.

It took me almost a day to figure things out - in our release setups, our code is obfuscated. The anonymous type mentioned earlier is compiler-generated, and then obfuscated. Since it's a private class, it's properties are renamed, which result in Windsor not being able to match properties to parameters.

Once that was clear, the solution was simple - I replaced the anonymous type with a regular class, and marked it as Serializable, which notifies the obfuscation not to touch it.

After that, things went back to work - the class was not obfuscated, which means that the properties where not renamed. That in turn meant that Windsor was able to match properties to parameters, and the factory was able to resolve the objects.