Tales from the Evil Empire

I’m learning Node currently, after years of doing ASP.NET MVC, and a bit of Python on a couple of projects. There are lots of habits to shake off, and there are things that I miss (such as ASP’s outstanding model binding), but there is also a very liberating power in JavaScript, that lets you do things in a much more straightforward and even cleaner way than you would otherwise. There’s a lot less ceremony, and you can focus on what counts. One thing that keeps astonishing me is how I can make my Node modules work together without coupling them.

Building WebAPI controllers in Orchard is fairly simple: just inherit from System.Web.Http.ApiController. You’ll then be able to inject dependencies exactly in the same way that you would anywhere in Orchard. WebAPI is designed so that the default behavior is that a controller represents a category of resources, such as a product, an article, etc. There’s a bunch of conventions in place so that just naming the methods on the controllers is enough to wire them up. If this REST-like behavior is what you’re after, that’s great, just apply the conventions and you’re good to go. If you need to stray from that model, and implement something closer to what you’d do with a regular MVC controller, you’ll need to do a little more work.

A preferred way of creating a JavaScript object from a JSON file is to use the require function. Require will take care of the file’s encoding, and will cache the results so reading the same file a second time will not hit the file system. Testing such code can seem challenging, however.

While there are a couple of really good Node.js IDEs (I use WebStorm), developing for Node on Windows is challenging. The platform is clearly built for Unix-type systems, and Windows support is a lagging afterthought. If your dev machine is running Windows, and you want to develop for Node, you’ll need to be aware of a number of things.

There’s a number of differences between regular MVC controllers and WebAPI controllers that make the latter much more suitable to building APIs: they are REST-centric, they can negotiate the format of the answer, etc. Implementing WebAPI controllers in Orchard is really simple. First, you need a route, and that will be the subject of this post.

Whenever you need to get the URL of a ASP.NET MVC action, you should use Url.Action (where URL is an instance of UrlHelper), and never hard-code the URL. This way, the URL is dynamically constructed from the available information in the Url.Action parameters and in the route table. If the route is changed, the results of the Url.Action call will change accordingly, and everything will continue to work. The same principles, of course, apply to WebAPI actions.

There are rare cases where you’ll want to be able to inject instances of classes that don’t implement IDependency. One example of this can be found in MvcModule in Orchard.Framework, which also provides a good example of how to do it. The idea is to derive from Module, and override the Load method to register factories for the types you want to expose:

MiniProfiler is a wonderful module. It’s especially good at showing you the select n+1 problems in your Orchard applications. For some reason that is not entirely clear to me, however, it is only active on the front-end. If you have to debug a performance issue in the dashboard, you’re out of luck. Fortunately, the limitation is entirely arbitrary, easy to find, and easy to remove.