Forum: Rails I18n Automatic localized routes using routing filter and user session

I would like to add localization to my rails apps in the prefix form,
fx /:locale/my/other/path/segments

As I understand it, you currently have to do sth like the following

map.resources :books, :path_prefix => '/:locale'

and then something like:

book_url(book, :locale => :da)

But I don't want to have to rewrite all my generated urls!!!
I would like to have the locale stored in the user session (as
retrieved from the route, perhaps using Sven's routing filter) and
then auto insert the :locale options if it is present, so I don't have
to rewrite the urls.

filter
  - always store route :locale entry in session[:locale]

book_url(book)

# calls ActionDispatch:Routing.url_for
# which dispatches to
ActionController::PolymorphicRoutes.polymorphic_url

But I can't seem to find the :locale option from here either in rails
core or I18n.
Should I simply monkeypatch polymorphic_url and force-add the locale
options to my liking or is there a better way? I thought Rails 3 was
all about avoiding monkeypatches ;)

Proposed hack of a solution

def polymorphic_url
  ...
  # add default locale from session (retrieved from prefix on route
path)
  args << {:locale => session[:locale]} if session[:locale]
  __send__(named_route, *args)
end

Any better ideas or solutions?

As described on http://guides.rubyonrails.org/i18n.html, you can use
default_url_options for that:

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

2010/3/5 Kristian Mandrup <kmandrup@gmail.com>:

I just found this:

http://stackoverflow.com/questions/212425/creating-routes-with-an-optional-path-prefix

Which was very old, but at the end had a recent link to this:

http://www.artweb-design.de/2007/5/13/concise-localized-rails-url-helpers-solved-twice

Which at the end proposed this simple solution :)

  map.with_options(:path_prefix => ":locale") do |m|
    m.resources :posts
    m.resources :stories
  end

And you have to add before filter to application controller to define
locale, such as

before_filter :define_locale

def define_locale
  if params[:locale] == nil
    I18n.locale = 'en'
  else
    I18n.locale = params[:locale]
  end
end

Yeah, I think that could work !!!

This should be a standard feature of Rails 3 as I see it and
documented in the Rails 3 User Guide ;)
This is how I imagine most people would use localization.

BTW:
I have tried to port the translate_routes to Rails 3. See
http://github.com/kristianmandrup/translate_routes
I still need some help in understanding how to port the old route
segments to the new style, which also supports optional segments.
Please fork my branch and go from there :)