Need to clean up your old sessions?

I picked up on the idea of using a shell ActiveRecord class to sweep old sessions by someone on the mailing list a long time ago. I simply tweaked the idea to accept flexible time parameters.

class Session < ActiveRecord::Base

  # time_ago examples: 
  #   30m => 30 minutes
  #   1h  => 1 hour
  #   3d  => 3 days
  def self.sweep(time_ago = nil)
    time = case time_ago
      when /^(\d+)m$/ then Time.now.utc - $1.to_i.minute
      when /^(\d+)h$/ then Time.now.utc - $1.to_i.hour
      when /^(\d+)d$/ then Time.now.utc - $1.to_i.day
      else Time.now.utc - 1.hour
    end
    self.delete_all "updated_on < '#{time.to_s(:db)}'"
  end

end

Now just schedule with cron...

$ crontab -e

    # Delete old session after 3 hours of no use. Run every 15 minutes.
    */15 * * * * /usr/local/bin/ruby /var/www/apps/cool_app/current/script/runner -e production "Session.sweep('3h')"