Today I committed the final changes to a large chunk of CruiseControl.NET work that I’m rather proud of, namely removing all Web Forms code from the Dashboard Web App.
‘What??’ you may cry. ‘You’ve stopped using ASP.NET??’ No, I’ve just stopped using Web Forms. Web Forms are those
.aspx files you write and their code behinds. They’re also the things that use server controls, view state and other such components that make up most of .NET web apps. I’m still using the ASP.NET runtime in the form of an IHttpHandler. This is a much more lightweight way of developing web apps, similar to Java’s Servlets.
So why have I done this and thrown away the incredibally rich
System.Web.UI namespace? Well for a number of reasons, but chiefly because of testability and simplicity.
Web Forms are hard things to unit test. Basically you can’t. This is because of how closely tied all Page implementations are into the ASP.NET framework. To introduce testability you have to keep your code-behinds very thin, but once you’ve got a few controls on your page this is tricky. Also, any logic that you put in the
.aspx file itself is even harder to test, and this includes any templates, grid setup or whatever.
ASP.NET Web Forms also seem to be incredibally complex to me. The Page class alone is a pretty big beast, with all those events going on under the hood. And don’t even start me on Data Grids and Data Binding. Easy to setup something up in a prototype, yes, but simple to maintain? I’m not convinced. Fundamentally, web apps should be simple. You have a request with a bunch of parameters and you produce a response which is (to most intents and purposes) a string. Now I know that Web Forms are supposed to introduce a new model above all this stuff, but I don’t think the abstraction works particularly well once you get beyond a prototype.
So anyway, I decided to try and get rid of using Web Forms. I’ve evolved a new web framework, based a little bit on WebWork. It has an ultra simple front-controller and is based on decorated actions. Views are just html strings, but I’m using NVelocity to generate them. I’m using an IHttpHandler to process requests, and at the moment I’m overriding the
.aspx extension to be handled by my custom handler, not the Web Forms handler.
Will this be any use outside of CruiseControl.NET? I’m not sure – I might just be going off on one. But that said a good number of my Java-developing colleagues in ThoughtWorks have migrated from using Struts to WebWork, for similar to reasons to why I’ve moved away from Web Forms. Is any of my code re-usable? I think so, indeed I hope to spin off the web framework as a separate open source project, but the point is it is possible to write perfectly decent web applications in .NET without using Web Forms.
Finally, I’d like to give significant kudos to Joe Walnes. He wrote some of WebWork, and badgered me to think about using it as a basis of a new web framework for .NET. He also introduced to me the ideas of using IHttpHandler’s as the entry point for such a custom framework and of overriding
.aspx handling to avoid reconfiguring IIS.