rubyで日本語のメール送信

gistfile1.rb

require "nkf"
require "net/smtp"

def sendmail(host, port, from, to, subject, body)
  body = <<EOT
From: #{from}
To: #{to.to_a.join(",")}
Subject: =?ISO-2022-JP?B?#{NKF.nkf("-jMB", subject)}?=
Date: #{Time::now.strftime("%a, %d %b %Y %X %z")}
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-2022-JP
Content-Transfer-Encoding: 7bit

#{NKF.nkf("-jm0", body)}
EOT

  Net::SMTP.start(host, port) do |smtp|
    smtp.send_mail body, from, to
  end
end