Customizing Generators in Rails 3

January 13, 2010

As you probably already know, Rails 3 is just around the corner. There are some pretty nice features being added and one of them is the ability to customize the way the generators work. I personally prefer Haml over ERB, RSpec over Test::Unit and Factory Girl over Fixtures. So let's see how we can configure a Rails 3 app to do that.

First, follow Yehuda's instructions on how to create a Rails 3 app. Next, you have to tell Rails that you want to use Haml, RSpec and Factory Girl. First, add this somewhere in the Gemfile:

gem "haml"

only :test do
  gem "rspec"
  gem "rspec-rails"
  gem "factory_girl"

Then, re-run the bundler and initialize the Haml plugin:

$ gem bundle
$ bin/haml --rails .

Finally, you have to install the custom generators for the frameworks that you want to use. I found a repo on github that already had RSpec, so I forked it and added Haml and Factory Girl. Clone the repo into the lib/generators directory of your app:

$ git clone git:// lib/generators

Now, in the config/application.rb file in your app, near the bottom there is a section related to config.generators. Put this in that section:

config.generators do |g|
  g.template_engine :haml
  g.test_framework :rspec, :fixture => true, :views => false
  g.fixture_replacement :factory_girl, :dir => "spec/factories"

Here is where we reap the benefits of the modularity in Rails 3. What this says is that we want to use Haml as the template enging, we want to use RSpec as the test framework and we want to generate fixtures with our generated specs, but we don't want to generate view specs and that instead of fixtures, we actually want to use factory girl and we want the factories to be put into spec/factories. Whew! So does this all work?

$ script/generate rspec:install
$ script/generate scaffold person name:string dob:date age:integer male:boolean bio:text

At this point you should see that Rails has generated what we want, which is scaffolding that uses Haml for the views, RSpec for the tests and Factory Girl for the fixtures. Run the migrations, start the server and open the browser http://localhost:3000/people to see your scaffolding in action.

Now if you try to actually run rake spec, you'll get an error, at least I do. I'm not sure that RSpec 1.X is going to ever work with Rails 3. I think the intent is for RSpec 2 to be compatible with Rails 3, so keep an eye out for that.

Posted in Technology | Tags FactoryGirl, RSpec, Rails, HAML | 2 Comments