Multilingual Rails Application

In rails application, I want to make it multilingual. We need to define YAML language files for all required languages and tell the Rails application which language it should currently use.

Rails I18n.locale saves the current language and can be read by the application.

Steps for language translation

Lets we use German and English language here for translation .

1. Add language.yml in config/locales

In /config/locales/en.yml

  en:
    hello: "Hello World"

In /config/locales/de.yml

  hi:
    hello: "hallo Welt"

2. Configuration changes

In rails application the default locale is :en for English. Add in config/application.rb

  config.i18n.load_path += Dir[Rails.root.join('config', 'locales', '**', '*.{rb,yml}')]

3. Setting and Passing the Locale

Setting a selected locale as current language is easy. You can set the locale in the ApplicationController using before_filter

  before_filter :set_locale

  def set_locale
    I18n.locale = params[:locale] if params[:locale].present?
  end

4. Adding Translations

Then we insert the links for the navigation in the app/views/layouts/application.html.erb:

  <p>
    <%= link_to_unless I18n.locale == :en, "English", locale: :en %>
    |
    <%= link_to_unless I18n.locale == :de, "Deutsch", locale: :de %>
  </p>

The I18n API’s translate method is used to translate the text into current language.

So, change the view to display translated text. Use I18n API’s #t helper to translated string as

e.g in posts#index

<h1><%=t :hello %></h1>

Now, when you run posts#index the heading will display translated string for hello as per language. You can test translation by switching languages.

5. Organization of Locale Files

Putting translations for all parts of an application in one file per locale could be hard to manage.so we can store these files in a hierarchy as follows.

|-defaults
|---de.rb
|---en.rb
|-models
|---post
|-----de.rb
|-----en.rb
|-views
|---defaults
|-----de.rb
|-----en.rb
|---posts
|-----de.rb
|-----en.rb