Gmail All Mail periodic deletion

gamdelete.rb

#!/usr/bin/env ruby
# Delete files from Gmail All Mail folder
# Needs proper Gmail account configuration
#
# ----------------------------------------------------------------------------
# "THE BEER-WARE LICENSE" (commit 34973274ccef6ab4dfaaf86599792fa9c3fe4689):
# <pablo@propus.com.br> wrote this file. As long as you retain this notice you
# can do whatever you want with this stuff. If we meet some day, and you think
# this stuff is worth it, you can buy me a beer in return Pablo Lorenzzoni
# ----------------------------------------------------------------------------

require 'net/imap'
require 'date'

USERNAME='user@example.com'
PASSWORD='hackme'
MAIL_SERVER='imap.gmail.com'
SOURCE_MAILBOX='[Gmail]/All Mail' 

imap = Net::IMAP.new(MAIL_SERVER, 993, usessl = true, certs = nil, verify = false)
imap.login(USERNAME, PASSWORD)
imap.select(SOURCE_MAILBOX)

date = (Time.now - (6 * 30 * 24 * 60 * 60)).to_datetime             # 6 months ago

to_delete_ary = imap.search(["BEFORE", Net::IMAP.format_date(date)])

puts "#{to_delete_ary.length} messages to delete since #{date}"

imap.store(to_delete_ary, "+FLAGS", [:Deleted])
imap.expunge

puts "done"

imap.logout
imap.disconnect