TIL #1: Multi-domain Translations with Rails and Gettext

Photo of Marcin Szmigiel

Marcin Szmigiel

Dec 7, 2017 • 4 min read

Welcome to brand new series of content where we will share short tips and pieces of knowledge.

This time Ruby on Rails!

Recently I was working on separating gettext translations in our project into separate domains. It's very useful in cases when some strings should be translated differently in different contexts. I will explain shortly how to use multiple domains for Gettext translations in your Rails app. Enjoy!

- Rails app

- grosser/fast_gettext - it's one of the commonly used alternatives for I18n.

By default, gettext is using single default domain. To have more than one domain we will need to overwrite gettext:setup task using our app configuration. Here are some examples which can show you how you can achieve that:

# config/application.rb
# Add configuration constant with list of translation domains you need

module MyApp
  class Application < Rails::Application
    TEXT_DOMAINS = %w(app frontend new_design).freeze

# lib/tasks/gettext.rake

# Remove the provided gettext setup task

# Use your custom translation repositories list
namespace :gettext do
  task :setup => [:environment] do
    FastGettext.translation_repositories.each_key do |domain|
      GetText::Tools::Task.define do |task|
        task.package_name = domain
        task.package_version = "1.0.0"
        task.domain = domain
        task.po_base_directory = locale_path
        task.mo_base_directory = locale_path
        task.files = files_to_translate
        task.enable_description = false
        task.msgmerge_options = gettext_msgmerge_options
        task.msgcat_options = gettext_msgcat_options
        task.xgettext_options = gettext_xgettext_options

# config/initializers/locale.rb
# Add gettext domain's based on constant from your app configuration

MyApp::Application::TEXT_DOMAINS.each do |domain|
  FastGettext.add_text_domain domain,
                              path: File.join(Rails.root, "locale"),
                              type: :po,
                              ignore_fuzzy: true,
                              report_warning: true
FastGettext.default_text_domain = "app"

Now rails gettext:setup and rails gettext:find should create files called app.pot, frontend.pot and new_design.pot. Every call of domain-based translation method (e.g. d_("new_design", "Some string from new design goes here")) will be translated based on the values in the domain pot file. Voila, problem solved!

TIL, or Today I Learned, is where our developers share the best tech stuff they found every day. You can find smart solutions for some issues, useful advices and anything which will make your developer life easier.

Photo by Patrick Tomasso on Unsplash

Photo of Marcin Szmigiel

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Marcin Szmigiel

Marcin has a mix of scientific and humanistic mind, that’s why he chose to study Human-Computer...
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