How to reset the timezone after handling a request.

gistfile1.rb

  around_filter :set_time_zone

  def set_time_zone
    old_time_zone = Time.zone
    Time.zone = current_user.time_zone if logged_in?
    yield
  ensure
    Time.zone = old_time_zone
  end

Use around_filter instead of before_filter to set the time zone in a Rails action. That way the thread-local time zone will be reset on the way out of handling this request.

See my comment in http://railscasts.com/episodes/106-time-zones-in-rails-2-1

You might be tempted to combine the first two lines of set_time_zone into one line with the comma assignment syntax and add "if logged_in?" to the one line in the ensure clause. Don't do it. If you did that, the user's time zone would leak out to the next request when the user logs out.