iwarshak / powermta

This is an extension to Ruby's net/smtp library that lets you take advantage
of PowerMTA's (port25.com) native mailmerge feature. 

If you are doing any kind of mass mailing and you want the message to be unique 
to each user, and not one email with 50000000 people bcc'ed on it, this 
extension is for you.

I extracted this library from schoolsout.com, which literally sends hundreds of thousands of 
time-sensitive emails a day.

Example usage:

require 'pmta_extension'

users = User.find(:all)

email_text =<<-EOF 
From: "your friendly social network" <support@nosebook.com>
To: [*to]
Subject: Howdy [firstname]

Dear [firstname],

Did you know that you have [friend_count] friends? You must be one popular [gender]!!!

Sincerely,
Your friends at NoseBook
EOF

addresses = []
users.each do |user|
  addresses << {:address => user.email, 
                :variables => {"firstname" => user.firstname, "friend_count" => user.friends.size, "gender" => 
                user.gender == "m" ? 'dude' : 'gal'}}
end

Net::SMTP.start('your.powermta.mailserver.com', 25) do |smtp|
  smtp.send_merge_message(email_text, 'support@nosebook.com', true, addresses)
end

That's it. Now instead of having to compose and send User.size custom emails
(which can take forever), you can send 1 mailmerge message to the PowerMTA server
(the mail server) and have it do all of the merging for you. 

Feel free to email me with any questions. Ian Warshak <iwarshak@stripey.net>