Ruby でメールの受信

Ruby で imap サーバーからメールを受信する方法です。

imap_get.rb

#! /usr/bin/ruby
# -*- coding: utf-8 -*-
#
#   imap_get.rb
#
#                   Nov/27/2017
#
# ---------------------------------------------------------------------
require 'net/imap'
require 'kconv'

STDERR.puts "*** 開始 ***"
# imapのsslを有効にする
imap_usessl = true

imap_host = 'imap.mail.yahoo.co.jp'
imap_port = 993

# imapのユーザ名とパスワード
imap_user = 'xxxxxx'
imap_passwd = 'yyyyyy'

search_criterias = ['ALL']

# メールヘッダの件名(Subject)
subject_attr_name = 'BODY[HEADER.FIELDS (SUBJECT)]'
# メール本文
body_attr_name = 'BODY[TEXT]'

imap = Net::IMAP.new(imap_host, imap_port, imap_usessl)

imap.login(imap_user, imap_passwd)

imap.examine('INBOX')

imap.search(search_criterias).each do |msg_id|
    msg = imap.fetch(msg_id, [subject_attr_name, body_attr_name]).first

    subject = msg.attr[subject_attr_name].toutf8.strip
    body = msg.attr[body_attr_name].toutf8.strip

    envelope = imap.fetch(msg_id, "ENVELOPE")[0].attr["ENVELOPE"]
    puts "Name: #{envelope.from[0].name}"
    puts "From: #{envelope.from[0].mailbox}@#{envelope.from[0].host}"
    puts subject
    puts body
    puts
end

imap.logout

puts    "*** 終了 ***"
# ---------------------------------------------------------------------

次の環境で動作を確認しました。

$ uname -a
Linux iwata 5.4.0-42-generic #46-Ubuntu SMP Fri Jul 10 00:24:02 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

$ ruby --version
ruby 2.7.0p0 (2019-12-25 revision 647ee6f091) [x86_64-linux-gnu]