Description

The Locale filter extracts segments matching /:locale from the beginning of the recognized path and exposes the page parameter as params. When a path is generated the filter adds the segments to the path accordingly if the page parameter is passed to the url helper.

incoming url: /de/products
filtered url: /products
params:       params[:locale] = 'de'

You can install the filter like this:

# in config/routes.rb
Rails.application.routes.draw do
  filter :locale
end

To make your named_route helpers or url_for add the locale segments you can use:

products_path(:locale => 'de')
url_for(:products, :locale => 'de'))