Heroku, CloudFlare, Devise, Trackable

user.rb

# NOTE: need to override Devise's Trackable `update_tracked_fields` when using CloudFlare & Heroku.
def update_tracked_fields(request)
  super

  # NOTE: need to pull the first IP out of a list of IPs since Heroku
  # will append CloudFlare's IP.
  old_current = self.current_sign_in_ip
  new_current = if request.headers["X-Forwarded-For"].present?
    request.headers["X-Forwarded-For"][/[0-9\.]+/]
  else
    request.remote_ip
  end
  
  self.last_sign_in_ip     = old_current || new_current
  self.current_sign_in_ip  = new_current
end