Claim today's Wellington Advent Calendar treat

advent.rb

# Fill in the following parameters:
params = { 
  'name_first' =>     '',
  'name_last' =>      '',
  'email' =>          '',
  'region' =>         'Wellington City'
}

# NOTE: You need to have the `nokogiri` gem installed
#
# Add the following to your crontab to get each treat automatically emailed to you
# at 1 AM each day:
#
# 0 1 * * * ruby advent.rb

require 'date'
require 'json'
require 'nokogiri'
require 'open-uri'

exit unless Date.today.month == 12

url = 'http://advent.wellingtonnz.com'
doc = Nokogiri.HTML(open(url))
inline = doc.xpath('//script[not(@src)]').map(&:text)
data = inline.map{ |js| js[/window\.data = (\[.+?\]);/,1] }.compact[0]
json = JSON.parse(data)
params['terms'] = 1 
params['sign_up'] = 0 
params['offer'] = json[Time.now.mday-1]['id']
Net::HTTP.post_form(URI.parse("#{url}/redeem"), params)