Abstractions and Models aren’t Infallible

Last week I made a comment on Twitter as a little reminder to myself (link) that you have to occasionally challenge and even change the basic abstractions and domain model of your application.  I was working to extend the new FubuMVC.Authentication project so that we could use Windows and form based authentication on the same application at work.  The core of FubuMVC.Authentication was harvested from Josh and I’s previous project that had much simpler requirements.  I tried for far too long to push the new square shaped functionality through the existing round-holed model.  Once I took a step back and laid out the requirements and how functionality did and did not vary from Windows to form based to Twitter/Facebook/OAuth authentication, the basic abstractions changed quite a bit and I finally got some stuff done that had me stuck.

In the same week, we started to do some detailed analysis for a new user story that everybody thought could be tricky.  Once we got the business partners to give us concrete scenarios of the problems we faced, my team realized that we flat out have to change the core of our Domain Model and the relationships between entities to avoid turning our code into the kind of thing that makes me snarky on Twitter.  In this case it’s not a terrible thing because it won’t break the existing end to end acceptance tests or even much about the user interaction design.

I think we’re going to be just fine with both the authentication and the Domain Model, but for the hat trick last week, I griped on Twitter about a silly little API usability problem with an OSS tool that we use and had just upgraded.  I’ve spent a quite bit of time looking through this OSS tool’s codebase because we interact with its internals extensively in another FubuMVC related project.  Without getting too detailed, I think that the way this OSS project models its problem domain internally makes the code more complicated and certainly harder to use for us than it could be if the basic abstractions were changed to another design.  In this case, I’m familiar with the project’s history and it’s easy to see how its internal model probably worked very well with the initial, relatively simple use cases from the first release.  This project is very successful by any standards (even the fact that people gripe about it so frequently in my twitter feed is a testament to how used the tool really is), but they still have to be paying an opportunity cost in building out their newer features.

Re-thinking previously made decisions isn’t an obvious move in most cases, but it’s still something you’re going to have to do as a software developer.


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