ruby - Adding a directory to the load path in Rails?

Question

As of Rails 2.3, what's the right way to add a directory to the load path so that it hooks into Rails' auto-reloading mechanisms?

The specific example I'm thinking of is I have a class that has several sub-classes using STI and I thought it would be a good idea to put them in a sub-directory rather than clutter the top-level. So I would have something like:

#app/models/widget.rb
class Widget < ActiveRecord::Base
   add_to_load_path File.join(File.dirname(__FILE__), "widgets")
end

#app/models/widgets/bar_widget.rb
class BarWidget < Widget
end

#app/models/widgets/foo_widget.rb
class FooWidget < Widget
end

It's the add_to_load_path method that I'm looking for.

Answer 1

In the current version of Rails (3.2.8), this has been changed in the application.rb file.

The code is currently commented out as:

  # Custom directories with classes and modules you want to be autoloadable.
  # config.autoload_paths += %W(#{config.root}/extras)

Will need to update the autoload_paths value. Attempting to modify the the former load_paths variable causes this error.

/configuration.rb:85:in `method_missing': undefined method `load_paths' for #<Rails::Application::Configuration:0xac670b4> (NoMethodError)

for an example, for each path to add to autoload_paths config, add a line similar to the following:

config.autoload_paths += %W(#{config.root}/app/validators)

---

config.autoload_paths accepts an array of paths from which Rails will autoload constants. Default is all directories under app.

http://guides.rubyonrails.org/configuring.html

---

From commentor (hakunin) below:

If the directory is under app/, you don't need to add it anywhere, it should just work by default (definitely in 3.2.12). Rails has eager_load_paths that acts as autoload_paths in development, and eager load in production. All app/* directories are automatically added there.