simple example to read email addresses from excel and send notifications to each email address

simple_notificaiton_system.rb

require 'rubygems'
require 'net/smtp'
require 'roo'

def load_receivers
  receivers = []

  excel_file = Roo::Excel.new(ENV['EXCEL'])
  2.upto(excel_file.last_row).each do |row|
    # Assume that the name is in the second column, and email is in the third column.
    # e.g. ['martin91', '[email protected]']
    receivers.push [excel_file.cell(row, 2), excel_file.cell(row, 3)]
  end

  receivers
end

def send_email(receiver_name, receiver_email)
  message = <<-END_OF_MESSAGE
From: Martin Hong <[email protected]>
To: #{receiver_name} <#{receiver_email}>
Subject: Subject Here
Date: #{Time.now}

Dear#{receiver_name},
    
    xxxxx messages here xxxxx

Best Regards,
Martin
  END_OF_MESSAGE

  smtp = Net::SMTP.new 'smtp.gmail.com', 587
  smtp.enable_starttls

  smtp.start('gmail.com', '[email protected]', ENV['PASSWORD'], :plain) do |smtp|
    smtp.send_message message, '[email protected]', receiver_email
  end
end

def send_notifications
  receivers = load_receivers

  receivers.each do |receiver|
    name, email = *receiver

    puts "Sending email to #{name}: #{email}..."
    send_email(name, email)
    puts "Email is sent to #{name}!"
  end
end

send_notifications