bot.rb

require 'http'
require 'json'
require 'eventmachine'
require 'faye/websocket'

response = HTTP.post("https://slack.com/api/rtm.start", params: { token: ENV['SLACK_API_TOKEN'] })
rc = JSON.parse(response.body)
url = rc['url']

EM.run do
  ws = Faye::WebSocket::Client.new(url)

  ws.on :open do
    p [:open]
  end

  ws.on :message do |event|
    data = JSON.parse(event.data)

    send_apology(ws, data, data['channel']) if data['text'] =~ /^[:](atsumori)[:]/
    send_apology(ws, data, data['item']['channel']) if data['reaction'] =~ /^(atsumori)/
  end

  ws.on :close do
    p [:close, event.code]
    ws = nil
    EM.stop
  end

  def send_apology(ws, data, channel)
    p [:message, data]
    ws.send({
      type: 'message',
      text: "失礼しました。熱盛と出てしまいました。",
      channel: channel
      }.to_json)
  end
end