Add internationalization to a Rails project

readme.md

Here described is my approach to add multiple languages to a Ruby on Rails project.

You have to edit:

• routes file
• the application controller
• the view

_locale_navbar_item.html.haml

%li.dropdown
  %a.dropdown-toggle{"data-toggle" => "dropdown", :href => "#"}
    = t(".#{I18n.locale}")
    %b.caret
  %ul.dropdown-menu
    - (I18n.available_locales.map(&:to_s)-[I18n.locale.to_s]).each do |loc|
      %li= link_to t(".#{loc}"), locale: loc

application_controller.rb

class ApplicationController < ActionController::Base
  before_action :set_locale

  ...

  def current_user_locale
    current_account.user.locale
  rescue
    I18n.default_locale
  end

  def set_locale
    loc = params[:locale]
    loc = nil if !I18n.available_locales.map(&:to_s).include?(loc)
    if current_account # user is logged in
      if loc && loc!=current_user_locale
        current_user.update_attribute(:locale, loc)
        I18n.locale = loc || I18n.default_locale
      else
        I18n.locale = loc || current_user_locale || I18n.default_locale
      end
    else
      I18n.locale = loc || I18n.default_locale
    end
  end

  def default_url_options(options={})
    { locale: I18n.locale }.merge options
  end
end

routes.rb

Gino::Application.routes.draw do

  scope "(:locale)", locale: /en|it/ do
    resources :groups
    resources :users do
      member do
        get :invite
      end
    end
    devise_scope :account do
      root to: "devise/sessions#new"
      get '/accounts/sign_out' => 'devise/sessions#destroy'
      get '/accounts/edit'     => 'devise/registrations#edit',   :as => 'edit_account_registration'
      put '/accounts'          => 'devise/registrations#update', :as => 'account_registration'
    end
    devise_for :accounts

  ...


end