Implement changing the language

lib/open_fest/app/controllers/open_fest/application_controller.rb

@@ -3,5 +3,16 @@ module OpenFest
     include ::CurrentConferenceAssigning
 
     before_filter :require_current_conference!
+    before_filter :set_locale
+
+    def set_locale
+      if params[:locale]
+        I18n.locale = params[:locale]
+      end
+    end
+
+    def default_url_options(options = {})
+      options.merge(locale: params[:locale])
+    end
   end
 end

lib/open_fest/app/views/open_fest/shared/_nav.slim

@@ -21,5 +21,11 @@ nav
           li
             = link_to t(:logout), destroy_user_session_path, method: :delete
         li
-          a href="#" hreflang="en"
+          - if I18n.locale == :bg
+            = link_to url_for(request.query_parameters.merge(locale: 'en')), hreflang: 'en' do
               img src="data:image/png;base64,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" title="English" alt="English"
+          - elsif I18n.locale == :en
+            = link_to url_for(request.query_parameters.merge(locale: 'bg')), hreflang: 'bg' do
+              img src="data:image/png;base64,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" title="Български" alt="Български"
+          - else
+            = I18n.locale.inspect

lib/open_fest/config/routes.rb

@@ -1,8 +1,10 @@
 OpenFest::Engine.routes.draw do
   root to: 'events#index'
 
+  scope '(/:locale)' do
     devise_for :users, module: 'open_fest/users'
 
     resource :personal_profile, path: 'profile'
     resources :events
+  end
 end