aws_cf_invalidate.rake

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

desc "Invalidate files from cloudfront distribution"
task :files, :filenames do |task, args|
  
  CONFIG = YAML.load_file(File.join(RAILS_ROOT, 'config', 'amazon_s3.yml'))[RAILS_ENV]
     
  s3_access = CONFIG['access_key_id']
  s3_secret = CONFIG['secret_access_key']
  cf_distribution = CONFIG['s3_assets_distribution_id']

  puts "Distribution id... #{cf_distribution}"
  
  paths = nil
  
  paths = '<Path>/' + args[:filenames].split(" ").join('</Path><Path>/') + '</Path>'

  date = Time.now.utc
  date = date.strftime("%a, %d %b %Y %H:%M:%S %Z")
  digest = HMAC::SHA1.new(s3_secret)
  digest << date

  puts "Parsing url..."
  uri = URI.parse('https://cloudfront.amazonaws.com/2010-08-01/distribution/' + cf_distribution + '/invalidation')
  
  puts "Posting to cloudfront... #{uri}"
  if paths != nil
    req = Net::HTTP::Post.new(uri.path)
  else
    req = Net::HTTP::Get.new(uri.path)
  end

  req.initialize_http_header({
    'x-amz-date' => date,
    'Content-Type' => 'text/xml',
    'Authorization' => "AWS %s:%s" % [s3_access, Base64.encode64(digest.digest)]
  })

  if paths != nil
    req.body = "<InvalidationBatch>" + paths + "<CallerReference>ref_#{Time.now.utc.to_i}</CallerReference></InvalidationBatch>"
  end

  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.code
  puts res.body
  
end