Simple Localization in Rails 2.2

from http://almosteffortless.com/2008/07/21/simple-localization-in-rails-22/

I’ve been staying on the sidelines when it comes to localization in Rails for a while now, but I couldn’t help getting excited about the upcoming native support in Rails 2.2. So, with someguidance from the Rails i18n team, I decided to give things a try.

I’ve been extremely pleased with the results so far, but I’m all ears if anyone would like to offer suggestions on how to better achieve basic localization for a Rails app. Here’s where I’m at so far in a kind of how-to format. This is all plugin-free, using only what’s available in core. I expect that plugins will be coming out to add features and functionality, but you can accomplish quite a bit without any extras.

You can try to follow along, or just get the gist be reading through the steps. As noted in the comments, this is just a proof of concept, is not secure, and shouldn’t be used in production as-is.

1. Make a new Rails app and freeze edge:

 
~ $ rails i18n
~ $ cd i18n
~ $ rake rails:freeze:edge

2. Make a couple of translation stores (files) in lib/locale directory:

 
# lib/locale/en-US.rb
{ 'en-US' => {
  :hello_world => "Hello World",
  :hello_flash => "Hello Flash"
}}

# lib/locale/pirate.rb
{ 'pirate' => {
  :hello_world => "Ahoy World",
  :hello_flash => "Ahoy Flash"
}}

3. Set I18n.locale with a before_filter:

 
# app/controllers/application.rb
class ApplicationController < ActionController::Base

  before_filter :set_locale

  def set_locale
    locale = params[:locale] || 'en-US'
    I18n.locale = locale
    I18n.load_path += Dir[ File.join(RAILS_ROOT, 'lib', 'locale', '*.{rb,yml}') ]
  end

end

4. Make a controller and route to test things out, using symbols from your translation for user messages:

 
# config/routes.rb
ActionController::Routing::Routes.draw do |map|
  map.root :controller => 'home', :action => 'index'
end

# app/controllers/home_controller.rb
class HomeController < ApplicationController
  def index
    flash[:notice] = :hello_flash
  end
end

5. Create a view using symbols for user messages and use the “t” helper to translate:

 
# app/views/home/index.html.erb
<h1><%=t :hello_world %></h1>

<%=t flash[:notice] %>

<%= link_to 'en-US', root_path(:locale => 'en-US') %> or
<%= link_to 'pirate', root_path(:locale => 'pirate') %>

6. Fire up the old script/server and check it out:

 
~ $ script/server

I think that about covers it. Of course, this is a very simple example, but it should cover the basics well enough to get started. Please let me know if you have any ideas about how to simplify/improve this, and thanks again to the Rails i18n team for all of their work – everything looks great so far!

Update: You can use YAML to store translations now. Also, the I18n.populate and I18n.store_translations are no longer necessary (or available).

 
# lib/locale/pirate.yml
pirate:
  hello_world: Ahoy World
  hello_flash: Ahoy Flash

# app/controllers/application.rb
I18n.load_path += Dir[ File.join(RAILS_ROOT, 'lib', 'locale', '*.{rb,yml}') ]

Update: Rails 2.2 comes with simple i18n support fully baked in. This is great news because it makes adding internationalization support even easier. Check out the announcement on the Rails site for details, but the short version is that YAML files put into config/locales can be loaded up with a simple call to their file name. Here’s an example:

 
# config/locales/en.yml
en:
  hello_world: Hello World

# config/environment.rb
config.i18n.default_locale = :en

# app/views/home/index.html.erb
<h1><%=t :hello_world %></h1>