Ruby script to parse mail and send to Slack using slacktee

mailbridge.rb

#!/usr/bin/env ruby
slacktee = '/usr/local/bin/slacktee.sh'
require 'mail'
require 'syslog'
require 'shellwords'
shortfields = ['to', 'from']
longfields = ['subject', 'date']
slackargs = "-p -a"
mail = Mail.new(STDIN.read)
mail.header.fields.to_a.each do |h|
    if longfields.include? h.name.downcase
        slackargs = "#{slackargs} -e #{h.name.shellescape} #{h.value.shellescape} "
    elsif shortfields.include? h.name.downcase
        slackargs = "#{slackargs} -s #{h.name.shellescape} #{h.value.shellescape} "
    end
end
output = %x( echo #{mail.decoded.shellescape} | #{slacktee} #{slackargs} )
Syslog.open("mailbridge", Syslog::LOG_CONS, Syslog::LOG_MAIL)
unless $?.success?
    Syslog.log(Syslog::LOG_ERR, "Error sending mail to slack: #{output}")
    exit 1
else
    Syslog.log(Syslog::LOG_INFO, "Mail to #{mail.to} sent to Slack")
end