A ruby script that acts like DynDns for your own domain (via DreamHost)

dyn-dns-dreamhost.rb

require 'open-uri'
require 'rubygems'
require 'json'

# Change these settings
hostname = 'home.hostname.com' # the hostname you use to connect to home ip
apikey = 'your-dreamhost-api-key' # a dreamhost api key that has access to all dns functions

storedIP = ''
print 'Getting current external ip: '
ip = open('http://checkip.dyndns.com'){ |f| /([1-9]{1,3}\.){3}[0-9]{1,3}/.match(f.read)[0].to_a[0] }
puts ip
print 'Getting stored ip from dreamhost for ' + hostname + ': '
dns = open( 'https://api.dreamhost.com/?key=' + apikey + 
            '&cmd=dns-list_records&format=json&unique_id=' + Time.now.to_f.to_s,
            'UserAgent' => 'RubyWget').read
result = JSON.parse(dns)

result['data'].each do |d|

  if d['record'] == hostname
    storedIP = d['value']
  end

end

puts storedIP

if ip != storedIP
  puts  'IP addresses do not match, changing Dreamhost ip for ' + hostname + ' from ' + storedIP + 
        ' to ' + ip + '.'
  dns = open( 'https://api.dreamhost.com/?key=' + apikey + 
              '&cmd=dns-remove_record&record=' + hostname + '&type=a&value=' + storedIP + 
              '&unique_id=' + Time.now.to_f.to_s,'UserAgent' => 'RubyWget').read
  print 'Removing current DNS entry: ' 
  puts dns
  dns = open( 'https://api.dreamhost.com/?key=' + apikey + 
              '&cmd=dns-add_record&record=' + hostname + '&type=a&value=' + ip + 
              '&unique_id=' + Time.now.to_f.to_s,'UserAgent' => 'RubyWget').read
  print 'Adding new DNS entry: ' 
  puts dns
else
  puts 'IPs addresses match. No need to DNS'
end