Ruby script interacting with the Amazon AWS CloudFront invalidation

amazon_cloudfront_invalidation.rb

require 'rubygems'
require 'hmac-sha1'
require 'net/https'
require 'base64'

AWS_KEY = '...'
AWS_SECRET = '...'
CLOUDFRONT_DISTRIBUTION_ID = '...'

date = Time.now.utc
date = date.strftime("%a, %d %b %Y %H:%M:%S %Z")
digest = HMAC::SHA1.new(AWS_SECRET)
digest << date

uri = URI.parse("https://cloudfront.amazonaws.com/2010-08-01/distribution/%s/invalidation" % [CLOUDFRONT_DISTRIBUTION_ID])

req = Net::HTTP::Post.new(uri.path)
req.initialize_http_header({
  'x-amz-date' => date,
  'Content-Type' => 'text/xml',
  'Authorization' => "AWS %s:%s" % [AWS_KEY, Base64.encode64(digest.digest)]
})
req.body = %|<InvalidationBatch><Path>PATH_TO_EXPIRE</Path><CallerReference>SOMETHING_SPECIAL_#{Time.now.utc.to_i}</CallerReference></InvalidationBatch>|

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true
http.verify_mode = OpenSSL::SSL::VERIFY_NONE
res = http.request(req)

puts res.inspect
puts res.body
puts res.code