update_slicehost_dns.rb

# 
#  update_slicehost_dns.rb
#  Updates the A record of a domain to your
#  current IP address
#  
#  Created by Caius Durling on 2009-07-30.
#  Copyright 2009 Caius Durling.
# 
# MIT Licence

# Change these to your details
my_api_key = "blahblahblah"
domain = "example.com."

# Ignore all this unless you're interested
require "rubygems"
require "activeresource"
require "open-uri"

SITE = "https://#{my_api_key}@api.slicehost.com"

class Zone < ActiveResource::Base
  self.site = SITE
  
  def records
    Record.find(:all, :params => {:zone_id => self.id})
  end
end

class Record < ActiveResource::Base
  self.site = SITE
end

# Find the domain, then the A record for said domain
zone = Zone.find(:first, :params => {:origin => domain})
exit(1) if zone.nil?
a_record = zone.records.select {|r| r.record_type = "A" }.first
exit(2) if a_record.nil?
# Then the current IP address
dns_ip = a_record.data

# Grab the current IP from akamai
live_ip = open("http://whatismyip.akamai.com/").read

# Check if the IP has changed
if live_ip != dns_ip
  # We need to update it!
  a_record.data = live_ip
  a_record.save
  puts "Updated A record from '#{dns_ip}' to '#{live_ip}'"
else
  puts "No update needed"
end