I’m releasing a new open-source app today. It’s called the Relatedness Calculator. It’s a pretty simple app: what it does is take the name of a relative, written in plain English, and calculate the relatedness coefficient for that relative. It even accepts complex English descriptions, like “father’s half-brother’s granddaughter.” Plus, it draws a family tree, so that you can visualize the relationship. It’s pretty fun if you’re into genealogy!
Why did I write this app? Well, the inspiration actually came from a strange place: a message board. On this message board, a guy was wondering if anyone though it would be weird to date a distant relative of his. He said she was his grandma’s cousin’s daughter, and although that’s a pretty big distance in the family tree, he was worried about the social stigma if the two of them were to get married. Having a layman’s interest in genetics, I did the math for him and told him that he was only 1.5% related to her. And if he compared that to cousins (12.5%), which is kind of the borderline of acceptability for most cultures, he could see that it’s not really a big deal.
Doing the math for such a far-flung relation, though, was kind of tough. I had to go back and re-read some of Richard Dawkin’s excellent The Selfish Gene to brush up on the calculations. And then I wanted to make sure that my math was right, so I wrote some Java classes to help me out. Then I started writing unit tests. Then I started writing a parser, and… well, sometimes when you’re moderately autistic, as many programmers are, you start to get carried away. So I did, and that became a standalone Java library.
At this point I knew I wanted to make an app out of this project, because I thought it was neat enough to interest a lot of people (and not just those who want to date their relatives). I could have easily built an Android app out of it, but I’ve already written 8 Android apps, and anyway I didn’t think it was the right platform. Nobody’s going to download such a trivial app to their phone. Also, there didn’t seem to be any general-purpose relatedness calculators on the web, so I thought: why not make my own?
This is my first published webapp, so in many ways it’s kind of a “hello world” for me. I used Grails, because it seemed like a nice framework, and Groovy is close to Java. Astute Grails fans will notice that I didn’t even bother to change the default theming, but that’s typically what I do when I write apps. I don’t have a head for design, so even with my Android apps I’ve always just used the default theme. I prefer focusing on functionality over flash.
To deploy the app was a bit complicated. I hesitated between choosing Google App Engine and Amazon EC2, but in the end I decided to go with the latter, because as it turned out I needed full OS access in order to run Graphviz on the command line in a separate process, which I don’t believe is supported by GAE.
I registered for an Amazon EC2 Micro instance because it’s free for one year, so we’ll see how it holds up. Even though the app is pretty lightweight – no persistence, no heavy computation, most everything cached – I’ve already seen some significant slowdown. Since the server is free, though, I can’t really complain.
The biggest difference I find with developing webapps versus Android apps is just the barrier to entry. When it comes to costs, being an Android developer will only run you the $25 signup fee, and then after that Google takes care of the rest. For a webapp, though, I need to pay $10-15/year for the domain name, and then my micro EC2 instance (after the first free year) will cost at least $15/month, plus more if the app is popular. That’s pretty steep for hobby apps like mine, which don’t even bring in any money.
As for deployment, you also don’t need to know how to set up a LAMP stack on Android, or how to build a WAR file, or even how to use the command line. You just submit your app to Google using the web interface, and you’re done.
When it comes to Android, I think an undergrad, with one or two intro Java courses under their belt, could probably build a decent app just by reading the Android tutorials. Building a webapp, on the other hand, requires a lot of additional specialized knowledge. Having come from a server-side background, and having had to figure this stuff out myself by trial and error, I can definitely say that web development is not for the faint of heart. It’s a global standard, and the W3C has tried to please everybody, so much of it feels like a Frankenstein’s monster of barely compatible compromises, rather than a holistic framework built from the ground up, like what Google did with Android.
And yet, web development is so… satisfying. I love that I can build this app, and now anybody with a browser can just point themselves to my site and make use of my code. It even works on mobile! Just play around with the CSS a bit, and you can turn your webapp into a perfectly functional, cross-platform mobile application. I suppose these observations seem pretty banal to folks who have been doing web development for forever, but for me, it’s still kind of amazing.