Get my public IP and send me email if it changes

myip.rb

#!/usr/bin/env ruby
# Get my public IP, store it, and email me if it changes
# Run from cron

require 'rubygems'
require 'net/https'
require 'gmail'
require 'mime'

time = Time.new
STRFTIME = time.strftime("%Y-%m-%d %H:%M:%S")
OLDIPFILE = '/some/dir'

# Functions
def send_email
  puts "#{STRFTIME} - Sending email via Gmail..."
  recip = 'me@gmail.com'
  subject = 'Public IP Address Has Changed'
  gmail = Gmail.new('me@gmail.com', 'PASSWORD')
  gmail.deliver do
    to "#{recip}"
    subject "#{subject}"
    text_part do
      body "#{MYIP}"
    end
  end
  gmail.logout
end

def update_ipfile
  puts "#{STRFTIME} - Updating #{OLDIPFILE} with current IP..."
  File.open("#{OLDIPFILE}","w") do |f|  
    f.puts "#{MYIP}"
  end
end
# End Functions

# Get IP
begin
  url = URI.parse "http://icanhazip.com"
  MYIP = Net::HTTP.get_response(url).body
rescue
  puts "#{STRFTIME} - error: #{$!}"
  abort "#{STRFTIME} - Couldn't connect to icanhazip.com. Exiting."
else
  # if oldip doesn't exist or is different than current IP,
  # copy current to oldip and send mail
  begin
    oldip = File.read("#{OLDIPFILE}")
  rescue
    puts "#{STRFTIME} - Can't find #{OLDIPFILE}."
    update_ipfile
    send_email
  else
    # compare MYIP and oldip
    if "#{oldip}" != "#{MYIP}"
      puts "#{STRFTIME} - Old IP is not the same as new IP... sending email."
      send_email
      update_ipfile
    else
      puts "#{STRFTIME} - Old IP is the same as new IP... exiting."
    end 
  end
end