Custom compression pipeline

Memory-Based Compression 

require 'cabriolet'
require 'stringio'

# Compress in memory without disk I/O
input_data = File.read('large_file.dat', mode: 'rb')
output_buffer = StringIO.new
output_buffer.set_encoding(Encoding::BINARY)

compressor = Cabriolet::CAB::Compressor.new(
  io: output_buffer,
  compression: :lzx
)

compressor.add_data('file.dat', input_data)
compressor.compress

# Get compressed data
cab_data = output_buffer.string
puts "Compressed #{input_data.size} to #{cab_data.size} bytes"

Custom I/O Handler 

require 'cabriolet'

class S3IOHandler < Cabriolet::System::IOHandler
  def initialize(bucket, key)
    @bucket = bucket
    @key = key
    @s3 = Aws::S3::Client.new
  end

  def read(offset, size)
    @s3.get_object(
      bucket: @bucket,
      key: @key,
      range: "bytes=#{offset}-#{offset + size - 1}"
    ).body.read
  end

  def size
    @s3.head_object(bucket: @bucket, key: @key).content_length
  end
end

# Use with Cabriolet
handler = S3IOHandler.new('my-bucket', 'archive.cab')
cabinet = Cabriolet::CAB::Parser.new.parse_io(handler)

Format Conversion Pipeline 

require 'cabriolet'
require 'zip'

# Convert CAB to ZIP
cab = Cabriolet::CAB::Parser.new.parse('archive.cab')

Zip::File.open('archive.zip', Zip::File::CREATE) do |zipfile|
  cab.files.each do |file|
    zipfile.get_output_stream(file.name) do |stream|
      stream.write(file.data)
    end
  end
end

puts "Converted CAB to ZIP"

See also