Spree language switch

_lang_choice.html.erb

<%
# app/views/spree/shared/_lang_choice.html.erb
# Deface + I18n.with_locale do not play well together, implementing it manually
saved_locale = I18n.locale
I18n.locale = I18n.locale == :fr ? :en : :fr
%>
<li class="lang-swich"><%= lang_switch_url %></li>
<% I18n.locale = saved_locale %>

base_help_decorator.rb

# app/helpers/spree/base_help_decorator.rb
Spree::BaseHelper.module_eval do
  def lang_switch_url
    url = if params[:controller] == 'spree/products' && params[:action] == 'show'
            { :id => @product.permalink }
          elsif params[:controller] == 'spree/taxons' && params[:action] == 'show'
            { :id => @taxon.permalink }
          else
            { }
          end
    link_to I18n.t("layout.#{I18n.locale}"), url
  end
end

lang_menu.rb

# app/overrides/lang_menu.rb
Deface::Override.new(:virtual_path  => "spree/layouts/spree_application",
                     :insert_bottom => "#nav-bar",
                     :partial       => "spree/shared/lang_choice",
                     :name          => "lang_menu")

Thanks for sharing! Successfully integrated on a Spree 1.2.0 project.

Used the Deface DSL in place of Deface::Override:

# overrides/spree/shared/_nav_bar/lang_menu.html.erb.deface
<!-- insert_bottom "#nav-bar" -->
<%= render "spree/shared/lang_choice" %>