How to check if a localization exists? - ruby-on-rails

Question

I am creating a little website which is currently being translated into different languages. I use Rails' out-of-the-box translation: l18n. To change the localization, a parameter called locale must be given, e.g.: http://localhost:3000/?locale=nl.
In ApplicationController this parameter is saved into a session variable and used as localization. How can I check if the locale actually exists? Are there any built in functions, or do I need to add an exists: "true" to every localization file to check it?

Answer 1

Rails will default to "en" as the default locale in case if a locale doesn't exist. So to be nasty if I pass http://localhost:3000/?locale=de and that translation doesn't exist, 'en' will be used.
Have a look here http://guides.rubyonrails.org/i18n.html , especially the section "2.3 Setting and Passing the Locale"
#config/initializers/available_locales.rb
# Get loaded locales conveniently
module I18n
class << self
def available_locales; backend.available_locales; end
end
module Backend
class Simple
def available_locales; translations.keys.collect { |l| l.to_s }.sort; end
end
end
end
# You need to "force-initialize" loaded locales
I18n.backend.send(:init_translations)
AVAILABLE_LOCALES = I18n.backend.available_locales
RAILS_DEFAULT_LOGGER.debug "* Loaded locales: #{AVAILABLE_LOCALES.inspect}"
You can then wrap the constant for easy access in ApplicationController:
class ApplicationController < ActionController::Base
def available_locales; AVAILABLE_LOCALES; end
end
You can implement it like this in your ApplicationController:
before_filter :set_locale
def set_locale
I18n.locale = extract_locale_from_params
end
def extract_locale_from_params
parsed_locale = params[:locale]
(available_locales.include? parsed_locale) ? parsed_locale : nil
end
HTH