Saturday, February 02, 2013

Ruby and Rails and all that stuff

At the suggestion of a recruiter, I'm learning Ruby on Rails this weekend. I was active on the comp.lang.python mailing list when Matz came around talking about Ruby. It seemed like a good thing, but I mostly ignored Ruby for years because it seemed to be solving problems that I already had solutions for with Python. Likewise, Rails seemed to retread the same ground already covered by Django.

Motivated to take another look because of the wild popularity of Rails, I see there's something in Ruby that deserves attention, which is blocks (anonymous closures, or what Lispers would call lambda expressions). They function as closures, and any language that makes a closure a first-class object is a good language. There are a ton of good Ruby tutorials. I myself am partial to Ruby in Twenty Minutes. There are also a good Rails tutorial (and I'm sure there are several others). Another notable thing in the Ruby community is RDoc, an unusually good documentation tool.

I'll be installing Ruby and Rails on an Ubuntu 12.04 machine. I don't like how old the packages are in the official Ubuntu repository, so I'll install from Ruby websites instead. The first thing to do is install RVM with these two commands:
$ curl -L | bash -s stable --ruby
$ source /home/wware/.rvm/scripts/rvm
Later I reversed my decision about the official repositories, when I discovered I could install "ruby1.9.3". What RVM offers is an ability to run multiple Ruby environments on the same machine, like Python's virtualenv.

So now Ruby is installed and you can type "irb" to begin an interactive Ruby session. Next install Rails, and some additional things you'll need soon:
$ gem install -V rails
$ sudo apt-get install libsqlite3-dev nodejs nodejs-dev
Now you can jump to step 3.2 of the Rails tutorial and you should be good to go. Or you can go to the Github repository (README) which I cloned from the folks, and that's where I'm going to be tinkering for a while.

When debugging Rails controller code, you'll want to uncomment "gem debugger" in Gemfile, insert "debugger" into your code, and then reload the page in your browser, and it will stop the development server and put you into an interactive shell with all the variables available in mid-process. You'll also have GDB commands like "step", "next", "continue", and breakpoints.

When you're ready to deploy, consider Heroku, a Rails hosting service that lets you use one virtual machine for free. I've deployed my Zombie Twitter app there, and after a few initial bumps, things have gone pretty smoothly.

Here's a custom search for Ruby and Rails: