How to expire fragment cache when locale changes?

Question

I'm trying to use fragment cache to cache the footer and navigation bar on a Ruby on Rails Site that uses I18n. The problem is, changing the language then shows you the footer and navigation bar in the wrong language. How do you go about expiring fragment cache when locale changes?

Answer 1

Rather than expiring the fragment cache, you should make the locale part of the cache key, i.e. something like

cache :locale => I18n.locale, ... do
  ...
end

This way different users can see different language versions of the footer/navigation bar but all will see cached versions.

Answer 2

When caching a fragment in Rails 3, this did the trick for me:

- cache([object, locale: I18n.locale]) do

Answer 3

I use to have this helper, so I don't need to explicitly pass the locale to each cache call:

# frozen_string_literal: true
module CacheHelper
  # Always using current I18n.locale to cache things.
  def cache(name = {}, options = {}, &block)
    name_with_locale = [name].flatten << I18n.locale.to_s
    super(name_with_locale, options, &block)
  end
end