Sending GMail from a Standalone Ruby Script

As part of my rails application, I need to send emails from a stand alone ruby script. For example, the back end of my rails application is a (currently) small postgres database. The easiest way to back it up is to send a database dump to myself via gmail.

There are several tutorials on how to send gmail directly from a rails app. Presented here is a method for doing it from a standalone script. This method assumes rails is installed, but the script itself runs outside of any rails application. In my case in the wee hours of the morning as a cron job.

Usage of this script would be something like:

require 'send_gmail'
hsh={:to=>'name@domain.com', :subject=>'subject', :body=>'body'}
SendGMail.send_gmail(hsh)

The script can also handle attachments, albeit in an unusual way. Instead of giving it a file, you give it the data directly, along with a filename, mime_type, and transfer encoding:

raw_attachment={:mime_type=>'application/x-gzip', :body=>make_body, :transfer_encoding=>'base64', :filename=>'backup.tar.gz' }
hsh[:raw_attachment]=raw_attachment

It should be easy enough to modify the script to handle files as attachments directly, but I didn't have such a need.

Here is the complete listing. My thanks to Stephun Chu, as most of this is cribbed from his aforementioned post.

Edit: Fixed syntax error - Thanks Nolan!  

send_gmail.rb


#!/usr/bin/env ruby
require 'rubygems'
gem 'actionmailer'
require 'action_mailer'
require 'openssl'
require 'net/smtp'

module SendGMail

@user_name='username@domain.com'
@domain='domain.com'
@password='password'


def SendGMail.send_gmail(hsh)

raw_attachments=hsh.fetch(:raw_attachements, [])
if hsh.has_key?(:raw_attachment)
 raw_attachments.push(hsh[:raw_attachment])
end

mail=TMail::Mail.new
mail.to=hsh[:to]
mail.date=Time.now
mail.from=@user_name
mail.subject=hsh[:subject]

main=mail
main=TMail::Mail.new
main.body = hsh[:body]
puts main.body
main.set_content_type('text/plain', nil, 'charset'=>'utf-8')
mail.parts.push(main)

for raw_attachment in raw_attachments
 part = TMail::Mail.new
 transfer_encoding=raw_attachment[:transfer_encoding]
 body=raw_attachment[:body]
 case (transfer_encoding || "").downcase
   when "base64" then
     part.body = TMail::Base64.folding_encode(body)
   when "quoted-printable"
     part.body = [body].pack("M*")
   else
     part.body = body
 end
    
 part.transfer_encoding = transfer_encoding
 part.set_content_type(raw_attachment[:mime_type], nil, 'name' => raw_attachment[:filename])
 part.set_content_disposition("attachment", "filename"=>raw_attachment[:filename])
 mail.parts.push(part)
end

mail.set_content_type('multipart', 'mixed') 
ActionMailer::Base.deliver(mail)

end

ActionMailer::Base.smtp_settings = {
:address => 'smtp.gmail.com',
:domain => @domain,
:authentication => :plain,
:port => 587,
:user_name => @user_name,
:password => @password
}

Net::SMTP.class_eval do
private
def do_start(helodomain, user, secret, authtype)
 raise IOError, 'SMTP session already started' if @started
 check_auth_args user, secret, authtype if user or secret

 sock = timeout(@open_timeout) { TCPSocket.open(@address, @port) }
 @socket = Net::InternetMessageIO.new(sock)
 @socket.read_timeout = 60 #@read_timeout
 @socket.debug_output = STDERR #@debug_output

 check_response(critical { recv_response() })
 do_helo(helodomain)

 raise 'openssl library not installed' unless defined?(OpenSSL)
 starttls
 ssl = OpenSSL::SSL::SSLSocket.new(sock)
 ssl.sync_close = true
 ssl.connect
 @socket = Net::InternetMessageIO.new(ssl)
 @socket.read_timeout = 60 #@read_timeout
 @socket.debug_output = STDERR #@debug_output
 do_helo(helodomain)

 authenticate user, secret, authtype if user
 @started = true
ensure
 unless @started
   # authentication failed, cancel connection.
     @socket.close if not @started and @socket and not @socket.closed?
   @socket = nil
 end
end

def do_helo(helodomain)
  begin
   if @esmtp
     ehlo helodomain
   else
     helo helodomain
   end
 rescue Net::ProtocolError
   if @esmtp
     @esmtp = false
     @error_occured = false
     retry
   end
   raise
 end
end

def starttls
 getok('STARTTLS')
end

def quit
 begin
   getok('QUIT')
 rescue EOFError, OpenSSL::SSL::SSLError
 end
end
end
end