Ruby script to delete multiple objects from Amazon S3 (via new Multi-Object Delete operation api)

s3_multi_object_delete.rb

require 'happening'

# Example:
# EM.run do
#   items = Happening::S3::ItemCollection.new 'bucket', ['key1', 'key2', ...], :aws_access_key_id => 'Your-ID', :aws_secret_access_key => 'secret'
#   items.delete
# end
module Happening

  #Monkey patch
  class AWS
    protected
    alias old_canonical_request_description canonical_request_description

    def canonical_request_description(method, path, headers = {}, expires = nil)
      description = old_canonical_request_description(method, path, headers, expires)
      description << '?delete'  if path[/[&?]delete($|&|=)/]
      description
    end
  end

  module S3
    #Monkey patch
    class Request
      protected
      def validate
      end
    end

    class ItemCollection < Item
      MULTIPLE_DELETE_LIMIT = 1000

      def initialize(bucket, keys, options = {})
        super bucket, "NO_USE", options
        @keys = keys
      end
      
      def path(with_bucket=true)
        with_bucket ? "/#{bucket}/?delete" : "/?delete"
      end

      def delete request_options = {}, &blk
        i = 0
        while i < @keys.size
          keys = @keys.slice(i, MULTIPLE_DELETE_LIMIT)
          data = "<Delete><Quiet>true</Quiet><Object><Key>" + keys.join("</Key></Object><Object><Key>") + "</Key></Object></Delete>"
          md5 = Base64.encode64(Digest::MD5.digest(data)).strip

          headers = aws.sign("POST", path, {"Content-MD5" => md5})
          request_options[:on_success] = blk if blk          
          request_options.update(:headers => headers, :data => data)
          Happening::S3::Request.new(:post, url, {:ssl => options[:ssl]}.update(request_options)).execute
          i += MULTIPLE_DELETE_LIMIT
        end
      end
    end
  end
end

if $0 == __FILE__
  if ARGV.length <= 3
    puts "Usage:"
    puts "s3_multi_object_delete.rb bucket s3id s3key key1 key2..."
    exit
  end
 
  keys = ARGV
  bucket = keys[0]
  s3id = keys[1]
  s3key = keys[2]
  keys.shift(3)

  EM.run do
    on_error = Proc.new {|response| puts "An error occured: #{response.response}"; EM.stop }
    items = Happening::S3::ItemCollection.new bucket, keys, :aws_access_key_id => s3id, :aws_secret_access_key => s3key, :protocol => 'http'
    items.delete(:on_error => on_error) do |response|
      puts "Deleted!"
      EM.stop
    end
  end
end