Using I18n with Hanami

Last week I wrote about settings up Sikekiq in Hanami. Another gem I often use is I18n since it allows to localize strings and keep them separated from my code by using a dedicated file. This way my code don’t have any hard-coded string but rather uses something that looks like a keys / values store.

Setup

You first should add I18n dependency explicitly to your Gemfile even if it’s already a dependency of hanami-validation because of dry-validation which is used underneath. So add this to your Gemfile:

gem 'i18n'

I18n needs some setup to know where to find translations and the default locale to use. You can set this in an initializer file so it will be loaded on server start, let’s create config/initializers/locale.rb:

require 'i18n'

I18n.load_path = Dir[Hanami.root.join("config/locales/**/*.{yml,rb}")]
I18n.default_locale = 'en'
I18n.backend.load_translations

Initializers in config/initializers are not auto-loaded so you need to require it explicitly in config/environment.rb:

require_relative './initializers/locale.rb'

With this simple setup you’re ready to go with Hanami-wide translations.

You can create translations files in config/locales sub-directories, for example English translations would go in config/locales/en/app.yml.

You could go further by adding the ability to create application specific translations. To do this, you need to instruct each application of it by adding some code in the configure block of its application.rb file:

configure do
  I18n.load_path << Dir[root.join("config/locales/**/*.{yml,rb}")]
  I18n.backend.load_translations
end

Now your applications can host their own translations so you won’t pollute global translation files with application specific stuff.

Using translations

Let’s see how you can use this translations in your code. It’s as simple as using I18n.t method.

For example in a view you can do:

<%= I18n.t('title') %>

and it will search for a key like en.title where en is the current locale.

You could also scope your call to a given namespace:

<%= I18n.t('title', scope: 'users.show') %>

Easier soon

According to this Github issue, I18n support should be shipped along with Hanami starting from v0.9.0. We can hope that it will be nicely integrated and that it’ll provide useful helpers out of the box.