Facebook Bot responds with code output

this script is a bot that will wait for anyone to mention you in a comment with language name and some code he want to execute and see the output, script will get the comment and parse it, then use an old script i have written before to execute scripts using eval.in website, gets the output and comment back to the same post with output, status code and a link to the code page on eval.in website.
you will need to create a facebook user, register it as a Developer, create a new application and get access token then modify the constants of the script (appid, appsecret) and then execute the script with access token as parameter and execute it again without parameter to make it listen to notifications, the script will work only on comments in groups, as i exclusively made it for egyptian geeks group, if you want you can remove the filter of notifications and it'll erspond to everyone, but that will be headache and my consume your application rate limit
the idea of this script is not mine, it is made before by other developers for IRC and Reddit, i created it for facebook :), have fun

Gist :

#!/usr/bin/env ruby
# Author : Emad Elsaid (https://github.com/blazeeboy)
# **Usage** : 
# 
# * `ruby evalin_comodor.rb <accesstoken>`
# this will get a long term access token from the short term one
# * `ruby evalin_comodor.rb`
# will start the script
require './evalin.rb' # https://github.com/blazeeboy/RubyScripts/blob/master/2014-3-30/evalin.rb
require 'koala' # gem install koala

# create a facebook app and get access token from here
# https://developers.facebook.com/tools/explorer
# scopes required : 
# public_profile, basic_info, publish_checkins, status_update, photo_upload, video_upload, create_note, share_item, publish_stream, manage_notifications, publish_actions, user_friends

APP_ID      = 'xxxxxxxxxxxxxxxx'
APP_SECRET  = 'xxxxxxxxxxxxxxxx'
NOTIFICATIONS_LIMIT = 100

if ARGV.size > 0
  oauth = Koala::Facebook::OAuth.new(APP_ID, APP_SECRET)
    new_access_info = oauth.exchange_access_token_info ARGV.first
    File.write 'token', new_access_info['access_token']
  puts 'New Access Token written'
  exit
end

# respond to comment with mention
def respond_to(graph, comment_id, post_id)

  comment = graph.get_object(comment_id)

  username = comment['from']['name']
  message = comment['message']
  puts "responding to : #{message}"

  # read comment parts languages and code
  groups = message.scan /#{$name}\s+([a-zA-Z+]+)(.+)/m
  return if groups.length != 1

  language = groups.first[0]
  code = groups.first[1].strip
  return unless output = evalin(code, language)

  # posting comment reply
  graph.put_object post_id, 'comments', {message: "#{username} \n#{output}"}

end

loop do
  begin
    # yes each time will read token
    # in case you started it then added access token
    # or refreshed it you won't need to restart it
    oauth_access_token = File.read('token')
    $graph = Koala::Facebook::API.new(oauth_access_token)

    # get your name
    $name = $graph.get_object('me')['name']

    # get notifications
    notifications = []
    page = $graph.get_connections('me','notifications')
    begin
      notifications += page
    end while page = page.next_page and notifications.length<=NOTIFICATIONS_LIMIT

    # 
    # Now lets head to parse and respond to them
    # 
    notifications.reverse_each do |n|
      begin
        if n['application'] and n['application']['name'] == 'Groups' and n['title'].include? 'mentioned you'

          ids = n['link'].scan /comment_id=([0-9]+)&/
          post_ids = n['link'].scan /permalink\/([0-9]+)\//
          if ids.size == 1 and post_ids.size == 1
            respond_to $graph, ids.first.first, post_ids.first.first 
          end

        end
      rescue 
        # ignore it
      end

      # mark notification as read
      $graph.put_object(n['id'],'', {unread: false})
    end
    puts "Notifications found : #{notifications.size}"

  # please rescue if something went wrong
  # thanks,
  rescue Exception => e
    puts "Error : #{e}"
  end

  # wait for 60 seconds and try again
  sleep 60
end