Welcome to yet another overview, this time it’s on the new I18n features in Rails 2.2 which you can install by typing gem install rails -s http://gems.rubyonrails.org -v 2.2.0.
Any mention of the t method in this guide are also spots where you can use translate too, they are just aliased methods (t is aliased to translate), it’s just much easier (for me) to type t than it is to type translate. Please excuse my laziness.
I’ve begun adding in the translation calls for rboard in my personal branch on GitHub and today I would like to show you how I’ve done it.
Firstly I have added these two lines to my config/environment.rb:
config/environment.rb
I18n.load_path = Dir.glob("#{RAILS_ROOT}/locales/*.rb")
I18n.default_locale = "en-AU"
This tells rails to load the translation files (aka locale files) from the locales directory in the root of my rails app, and they are in a ruby format. Alternatively you could load yaml files. this also tells it to set the default locale as “en-AU”, which will load locales/en-AU.rb by default.
My (incomplete) translation file looks like this: locales/en-AU.rb
{
:'en-AU' => {
:forum_heading => "Forum",
:topics_heading => "Topics",
:posts_heading => "Posts",
:last_post_heading => "Last Post",
:no_forums => "There are no forums.",
:administrator_should_create_forum => "Maybe an administrator should create one.",
:you_should_create_forum => "Maybe you should create a forum.",
:forum_statistics => "Forum Statistics",
:posts_per_topic => "Posts per topic",
:recent_users => "Users on in the last 15 minutes",
:registered_users => "Registered Users",
:home => "Home",
:edit_profile => "Edit Profile",
:member_list => "Member List",
:search => "Search",
:new_message => "new message",
:logout => "Logout",
:time_now => "The time is now",
:viewing_forum => "Viewing forum",
:new_topic => "New Topic",
:moderation_heading => "Moderation",
:topic_heading => "Topic",
:replies_heading => "Replies",
:views_heading => "Views",
:author_heading => "Author",
:ago => "ago",
:by => "by"
}
}
When I have a string I want translated in my app I will simply call stuff like t(:author_heading) and Rails will look up the correct translation for it, which in this case is just “Author”.
Now if I had another translation file, say locales/es.rb and I had Spanish users on rboard they could select a locale from their profile page and that would store it as a string on their user record. To translate this, we can use a before_filter on the application controller:
app/controllers/application.rb
class ApplicationController < ActionController::Base
before_filter :set_locale
def set_locale
I18n.locale = current_user.locale if logged_in?
end
end
This will set the locale to whatever the user has set, providing that they are logged in.
Interpolation
If you wish to insert a value into a translation you can use interpolation. To do this you can specify the t method call like this:
in a i18n-friendly file somewhere
<%= t(:welcome, :user => current_user.login) %>
And then in your locales file specify this:
locales/en-AU.rb
:welcome => "welcome !"
And the output of the translation will now be “welcome Ryan!” or whatever the user login was.
Counting
If you have a translation such as :x_new_messages in your translation file and you want the output of this translation to be correctly pluralized you can pass the count option to this:
In any t method supporting files
<%= t(:x_new_messages, :count => current_user.messages.size) %>
The x_ prefix to our translation is not important, it’s just there to show us that this translation may return different results depending on the count that is passed to it.
Then in your translation file you can do:
locales/en-AU.rb
:x_new_messages => {:zero => 'No new messages', :one => 'One new message', :other => '9 new messages'}
And depending on the value of count it will return one of those three outcomes.
Forcing a Locale
If you want to force a locale on a single translation you can do this by specifying the :locale</option> to the t method call like so:
<%= t(:english, :locale => "en-AU") %>
And this will always show the en-AU translation of the english key in the en-AU.rb locale file.
Alternative Translations
If one of your translations does not match like:
<%= t(:norsk) %>
You can have I18n fall back to any number of other translations:
<%= t(:norsk, :default => [:norwegian, :up_north, :northwards, "norway"]) %>
I18n will attempt to get a default translation from the options specified and will select the first one. If all translations failed then the string version, “norway” will be outputted.
Retrieving Multiple Translations
To get multiple translations back at the same time you can specify an array as the first argument to the t method.
<%= t(:forums, :topics) %>
Assuming you have correct translations for forums and topics you will get the translated versions returned in an array. Assuming you don’t have the correct translations for forums OR topics you will get back a string version of whatever translation is missing, possibly wrapped in a <span class=’translation_missing’></span>.
Further translation files can be found at Sven Fuch’s Github Repository