Multiple session objects

Sometimes you may want to have several session objects. For example, in group chat one session object tracks data which is about the chat and other session tracks user-specific data:

protected

# Default `#session` tracks user-specific data.
def session_key
  "#{bot.username}:#{from['id']}" if from
end

# It defines one more session object.
# This one will hold same data for all updates in group chat.
def chat_session
  @_chat_session ||= self.class.build_session(chat && "#{bot.username}:#{chat['id']}")
end

# Note that you need to save it yourself, like it done in Session module:
def process_action(*)
  super
ensure
  chat_session.commit if @_chat_session
end