Rack::LocaleMemorable

Handle query params, cookie and HTTP_ACCEPT_LANGUAGE header to detect user-preffered locale, and remember it when necessary.

Since some libraries (e.g., Devise & Warden) or applications may handle i18n strings in rack-middleware layer, setting I18n.locale in Rails layer is not enough in such cases.

This gem sets I18n.locale in rack-middleware layer, so that you can let other rack-middlewares use proper I18n.locale.

Install the gem and add to the application's Gemfile by executing:

$ bundle add rack-locale_memorable

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install rack-locale_memorable

# in initializers/middlewares.rb etc.
Rails.application.configure do |config|
  config.middleware.use Rack::LocaleMemorable
end

By default, this gem handles locale variables in 3 places in the order below, and when explicit locale is specified (= when locale is specified via query params) in the request, remember it in cookie too.

1. params['locale'] as explicit locale
2. cookies['locale'] as remembered locale
3. headers['HTTP_ACCEPT_LANGUAGE'] as implicit locale

There are several customizable options listed below.

• params_key ('locale' by default)
• cookie_key ('locale' by default)
• cookie_options[:lifetime] (1.year by default)
• cookie_options[:domain] (nil by default)
• cookie_options[:path] (/ by default)
• cookie_options[:http_only] (true by default)
• cookie_options[:secure] (true by default)
• cookie_options[:same_site] (nil by default)

You can customize them like below

Rails.application.configure do |config|
  config.middleware.use(
    Rack::LocaleMemorable,
    params_key: 'ui_locale',
    cookie_key: 'ui_locale',
    cookie_options: {
      lifetime:  3.months,
      domain:    'example.com',
      path:      '/localized',
      http_only: false,
      secure:    Rails.env.production?,
      same_site  :none
    }
  )
end

NOTE: If you're using devise, set Rack::LocaleMemorable before Warden::Manager, otherwise you might see warden error messages in wrong locale.

Rails.application.configure do |config|
  config.middleware.insert_before Warden::Manager, Rack::LocaleMemorable
end

ref.) related issue in devise & warden

• heartcombo/devise#5247
• wardencommunity/warden#180

See rspec results.

% bundle exec rspec --format=documentation

Rack::LocaleMemorable
  with no locales
    behaves like handled_with_default_locale
      should use default locale
  channel priority
    when locale is specified
      via query
        when different locale is included
          in cookie
            behaves like handled_with_expected_locale
              should use expected locale
            behaves like remember_expected_locale
              should remember expected locale
          in header
            behaves like handled_with_expected_locale
              should use expected locale
            behaves like remember_expected_locale
              should remember expected locale
          in cookie & header
            behaves like handled_with_expected_locale
              should use expected locale
            behaves like remember_expected_locale
              should remember expected locale
      via cookie
        when different locale is included
          in header
            behaves like handled_with_expected_locale
              should use expected locale
            behaves like remember_no_locale
              should not remember any locale
              :

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/nov/rack-locale_memorable. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in the Rack::LocaleMemorable project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.