# Don't write unchanged sessions to store.                                 
# Brian Ellin - brian -at- janrain.com                                     

class CGI::Session::ActiveRecordStore::Session

  # Special version of @data which keeps a copy of the orig                
  # session data for comparison before save.                               
  def data
    @data ||= self.class.unmarshal(read_attribute(@@data_column_name)) || \
{}
    # keep a *deep* copy of the session data                               
    @data_copy ||= self.class.unmarshal(read_attribute(@@data_column_name)\
) || {}
    @data
  end

  # Has the session data changed?                                          
  def needs_saving?
    return false unless loaded?
    return @data != @data_copy
  end

end

class CGI::Session::ActiveRecordStore

  # Version of close that hooks in with sesion container's                 
  # needs_saving? method.                                                  
  def close
    if @session
      if @session.needs_saving?
        update
      end
      @session = nil
    end
  end
end