RouteTranslator is a gem to allow you to manage the translations of your app routes with a simple dictionary format.

It started as a fork of the awesome translate_routes plugin by Raúl Murciano.

Right now it works with Rails 5.x and Rails 6.x

1. If you have this routes.rb file originally:

   Rails.application.routes.draw do
     namespace :admin do
       resources :cars
     end
   
     resources :cars
   end

   The output of rake routes.rb would be:

       admin_cars GET    /admin/cars(.:format)          admin/cars#index
                  POST   /admin/cars(.:format)          admin/cars#create
    new_admin_car GET    /admin/cars/new(.:format)      admin/cars#new
   edit_admin_car GET    /admin/cars/:id/edit(.:format) admin/cars#edit
        admin_car GET    /admin/cars/:id(.:format)      admin/cars#show
                  PUT    /admin/cars/:id(.:format)      admin/cars#update
                  DELETE /admin/cars/:id(.:format)      admin/cars#destroy
             cars GET    /cars(.:format)                cars#index
                  POST   /cars(.:format)                cars#create
          new_car GET    /cars/new(.:format)            cars#new
         edit_car GET    /cars/:id/edit(.:format)       cars#edit
              car GET    /cars/:id(.:format)            cars#show
                  PUT    /cars/:id(.:format)            cars#update
                  DELETE /cars/:id(.:format)            cars#destroy
   

2. Add the gem to your Gemfile:

   gem 'route_translator'

   And execute bundle install

3. Wrap the groups of routes that you want to translate inside a localized block:

   Rails.application.routes.draw do
     namespace :admin do
       resources :cars
     end
   
     localized do
       resources :cars
   
       get 'pricing', to: 'home#pricing', as: :pricing
     end
   end

   And add the translations to your locale files, for example:

   es:
     routes:
       cars: coches
       new: nuevo
       pricing: precios
   fr:
     routes:
       cars: voitures
       new: nouveau
       pricing: prix

4. Your routes are translated! Here's the output of your rake routes now:

           Prefix Verb   URI Pattern                     Controller#Action
       admin_cars GET    /admin/cars(.:format)           admin/cars#index
                  POST   /admin/cars(.:format)           admin/cars#create
    new_admin_car GET    /admin/cars/new(.:format)       admin/cars#new
   edit_admin_car GET    /admin/cars/:id/edit(.:format)  admin/cars#edit
        admin_car GET    /admin/cars/:id(.:format)       admin/cars#show
                  PATCH  /admin/cars/:id(.:format)       admin/cars#update
                  PUT    /admin/cars/:id(.:format)       admin/cars#update
                  DELETE /admin/cars/:id(.:format)       admin/cars#destroy
          cars_fr GET    /fr/voitures(.:format)          cars#index {:locale=>"fr"}
          cars_es GET    /es/coches(.:format)            cars#index {:locale=>"es"}
          cars_en GET    /cars(.:format)                 cars#index {:locale=>"en"}
                  POST   /fr/voitures(.:format)          cars#create {:locale=>"fr"}
                  POST   /es/coches(.:format)            cars#create {:locale=>"es"}
                  POST   /cars(.:format)                 cars#create {:locale=>"en"}
       new_car_fr GET    /fr/voitures/nouveau(.:format)  cars#new {:locale=>"fr"}
       new_car_es GET    /es/coches/nuevo(.:format)      cars#new {:locale=>"es"}
       new_car_en GET    /cars/new(.:format)             cars#new {:locale=>"en"}
      edit_car_fr GET    /fr/voitures/:id/edit(.:format) cars#edit {:locale=>"fr"}
      edit_car_es GET    /es/coches/:id/edit(.:format)   cars#edit {:locale=>"es"}
      edit_car_en GET    /cars/:id/edit(.:format)        cars#edit {:locale=>"en"}
           car_fr GET    /fr/voitures/:id(.:format)      cars#show {:locale=>"fr"}
           car_es GET    /es/coches/:id(.:format)        cars#show {:locale=>"es"}
           car_en GET    /cars/:id(.:format)             cars#show {:locale=>"en"}
                  PATCH  /fr/voitures/:id(.:format)      cars#update {:locale=>"fr"}
                  PATCH  /es/coches/:id(.:format)        cars#update {:locale=>"es"}
                  PATCH  /cars/:id(.:format)             cars#update {:locale=>"en"}
                  PUT    /fr/voitures/:id(.:format)      cars#update {:locale=>"fr"}
                  PUT    /es/coches/:id(.:format)        cars#update {:locale=>"es"}
                  PUT    /cars/:id(.:format)             cars#update {:locale=>"en"}
                  DELETE /fr/voitures/:id(.:format)      cars#destroy {:locale=>"fr"}
                  DELETE /es/coches/:id(.:format)        cars#destroy {:locale=>"es"}
                  DELETE /cars/:id(.:format)             cars#destroy {:locale=>"en"}
       pricing_fr GET    /fr/prix(.:format)              home#pricing {:locale=>"fr"}
       pricing_es GET    /es/precios(.:format)           home#pricing {:locale=>"es"}
       pricing_en GET    /pricing(.:format)              home#pricing {:locale=>"en"}
   

   Note that only the routes inside a localized block are translated.

   In :development environment, I18n is configured by default to not use fallback language. When a translation is missing, it uses the translation key last segment as fallback (cars and new in this example).

   In :production environment, you should either set config.i18n.fallbacks = false or set up translations for your routes in every languages.

5. If you want to set I18n.locale from the url parameter locale, add the following line in your ApplicationController or in the controllers that have translated content:

   around_action :set_locale_from_url

   Note: you might be tempted to use before_action instead of around_action: just don't. That could lead to thread-related issues.

To change the language and reload the appropriate route while staying on the same page, use the following code snippet:

link_to url_for(locale: 'es'), hreflang: 'es', rel: 'alternate'

Although locales are stored by Rails as a symbol (:es), when linking to a page in a different locale you need to use a string ('es'). Otherwise, instead of a namespaced route (/es/my-route) you will get a parameterized route (/my-route?locale=es).

If the page contains a localized slug, the above snippet does not work and a custom implementation is neede.

More information at Generating translated URLs

You can translate a namespace route by either its name or path option:

1. Wrap the namespaces that you want to translate inside a localized block:

   Rails.application.routes.draw do
     localized do
       namespace :admin do
         resources :cars, only: :index
       end
   
       namespace :sold_cars, path: :sold do
         resources :cars, only: :index
       end
     end
   end

   And add the translations to your locale files, for example:

   es:
     routes:
       admin: administrador
       cars: coches
       new: nuevo
       pricing: precios
       sold: vendidos
   fr:
     routes:
       admin: administrateur
       cars: voitures
       new: nouveau
       pricing: prix
       sold: vendues

2. Your namespaces are translated! Here's the output of your rake routes now:

              Prefix Verb URI Pattern                           Controller#Action
       admin_cars_fr GET  /fr/administrateur/voitures(.:format) admin/cars#index {:locale=>"fr"}
       admin_cars_es GET  /es/administrador/coches(.:format)    admin/cars#index {:locale=>"es"}
       admin_cars_en GET  /admin/cars(.:format)                 admin/cars#index {:locale=>"en"}
   sold_cars_cars_fr GET  /fr/vendues/voitures(.:format)        sold_cars/cars#index {:locale=>"fr"}
   sold_cars_cars_es GET  /es/vendidos/coches(.:format)         sold_cars/cars#index {:locale=>"es"}
   sold_cars_cars_en GET  /sold/cars(.:format)                  sold_cars/cars#index {:locale=>"en"}
   

At the moment inflections are not supported, but you can use the following workaround:

localized do
  resources :categories, path_names: { new: 'new_category' }
end

en:
  routes:
    category: category
    new_category: new

es:
  routes:
    category: categoria
    new_category: nueva

          Prefix Verb   URI Pattern                       Controller#Action
   categories_es GET    /es/categorias(.:format)          categories#index {:locale=>"es"}
   categories_en GET    /categories(.:format)             categories#index {:locale=>"en"}
                 POST   /es/categorias(.:format)          categories#create {:locale=>"es"}
                 POST   /categories(.:format)             categories#create {:locale=>"en"}
 new_category_es GET    /es/categorias/nueva(.:format)    categories#new {:locale=>"es"}
 new_category_en GET    /categories/new(.:format)         categories#new {:locale=>"en"}
edit_category_es GET    /es/categorias/:id/edit(.:format) categories#edit {:locale=>"es"}
edit_category_en GET    /categories/:id/edit(.:format)    categories#edit {:locale=>"en"}
     category_es GET    /es/categorias/:id(.:format)      categories#show {:locale=>"es"}
     category_en GET    /categories/:id(.:format)         categories#show {:locale=>"en"}
                 PATCH  /es/categorias/:id(.:format)      categories#update {:locale=>"es"}
                 PATCH  /categories/:id(.:format)         categories#update {:locale=>"en"}
                 PUT    /es/categorias/:id(.:format)      categories#update {:locale=>"es"}
                 PUT    /categories/:id(.:format)         categories#update {:locale=>"en"}
                 DELETE /es/categorias/:id(.:format)      categories#destroy {:locale=>"es"}
                 DELETE /categories/:id(.:format)         categories#destroy {:locale=>"en"}

You can configure RouteTranslator via an initializer or using the different environment config files.

RouteTranslator.config do |config|
  config.force_locale = true
  config.locale_param_key = :my_locale
end

If you have an application serving requests from more than one domain, you might want to set I18n.locale dynamically based on which domain the request is coming from.

The host_locales option is a hash mapping hosts to locales, with full wildcard support to allow matching multiple domains/subdomains/tlds. Host matching is case insensitive.

When a request hits your app from a domain matching one of the wild-card matchers defined in host_locales, the locale will be set to the specified locale. Unless you specified the force_locale configuration option to true, that locale will be hidden from routes (acting like a dynamic hide_locale option).

Here are a few examples of possible mappings:

RouteTranslator.config.host_locales =
  {                                # Matches:
    '*.es'                 => :es, # TLD:         ['domain.es', 'subdomain.domain.es', 'www.long.string.of.subdomains.es'] etc.
    'ru.wikipedia.*'       => :ru, # Subdomain:   ['ru.wikipedia.org', 'ru.wikipedia.net', 'ru.wikipedia.com'] etc.
    '*.subdomain.domain.*' => :ru, # Mixture:     ['subdomain.domain.org', 'www.subdomain.domain.net'] etc.
    'news.bbc.co.uk'       => :en, # Exact match: ['news.bbc.co.uk'] only
  }

In the case of a host matching more than once, the order in which the matchers are defined will be taken into account, like so:

RouteTranslator.config.host_locales = { 'russia.*' => :ru, '*.com'    => :en } # 'russia.com' will have locale :ru
RouteTranslator.config.host_locales = { '*.com'    => :en, 'russia.*' => :ru } # 'russia.com' will have locale :en

If host_locales option is set, the following options will be forced (even if you set to true):

@config.force_locale                        = false
@config.generate_unlocalized_routes         = false
@config.generate_unnamed_unlocalized_routes = false
@config.hide_locale                         = false

This is to avoid odd behaviour brought about by route conflicts and because host_locales forces and hides the host-locale dynamically.

NOTE: locale from parameters has priority over the one from hosts.

If you have routes that (partially) share names in one locale, but must be translated differently in another locale, for example:

get 'people/favourites', to: 'people/products#favourites'
get 'favourites',        to: 'products#favourites'

Then it is possible to provide different translations for common parts of those routes by scoping translations by a controller's namespace:

es:
  routes:
    favourites: favoritos
    controllers:
      people:
        products:
          favourites: fans

Routes will be translated as in:

people_products_favourites_es GET  /people/products/fans(.:format)       people/products#favourites {:locale=>"es"}
       products_favourites_es GET  /products/favoritos(.:format)         products#favourites {:locale=>"es"}

The gem will lookup translations under controllers scope first and then lookup translations under routes scope.

If you need complex routing as /:country/:locale/path/to/some/pages, you can specify the position of your locale parameter in the following way:

scope ':country/:locale' do
  localized do
    root to: 'content#homepage'
  end
end

Testing your controllers with routes-translator is easy, just add a locale parameter as String for your localized routes. Otherwise, an ActionController::UrlGenerationError will raise.

describe 'GET index' do
  it 'should respond with success' do
    # Remember to pass the locale param as String
    get :index, locale: 'fr'

    expect(response).to be_success
  end
end

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