CODEWITHSUNDEEP
rubydirectorycompressionzlib
6ft Dan
6ft Dan

Reputation: 2445

Compress a complete directory in Ruby with zlib?

This is the code I'm trying.

require 'zlib'
Dir.glob('*.*').each do |file|
  Zlib::GzipWriter.open('output.gz') do |gz|
    gz.mtime = File.mtime(file)
    gz.orig_name = File.basename(file)
    gz.write IO.binread(file)
  end
end

I've tried different variations of this. There doesn't seem to be a howto for "multiple files" online. I keep ending up with the first file name in the ouput.gz, and I think it may have the content of the last file from the directory (not sure). But that's besides the point. I just want to put each file as separate entities in a compressed file. The more cross platform compatible it is the better.

Upvotes: 1

Views: 3082

Answers (2)

6ft Dan
6ft Dan

Reputation: 2445

This answer is taken from http://old.thoughtsincomputation.com/posts/tar-and-a-few-feathers-in-ruby who took it from the RubyGems library.

require 'rubygems'
require 'rubygems/package'
require 'zlib'
require 'fileutils'

module Util
  module Tar
    # Creates a tar file in memory recursively
    # from the given path.
    #
    # Returns a StringIO whose underlying String
    # is the contents of the tar file.
    def tar(path)
      tarfile = StringIO.new("")
      Gem::Package::TarWriter.new(tarfile) do |tar|
        Dir[File.join(path, "**/*")].each do |file|
          mode = File.stat(file).mode
          relative_file = file.sub /^#{Regexp::escape path}\/?/, ''

          if File.directory?(file)
            tar.mkdir relative_file, mode
          else
            tar.add_file relative_file, mode do |tf|
              File.open(file, "rb") { |f| tf.write f.read }
            end
          end
        end
      end

      tarfile.rewind
      tarfile
    end

    # gzips the underlying string in the given StringIO,
    # returning a new StringIO representing the 
    # compressed file.
    def gzip(tarfile)
      gz = StringIO.new("")
      z = Zlib::GzipWriter.new(gz)
      z.write tarfile.string
      z.close # this is necessary!

      # z was closed to write the gzip footer, so
      # now we need a new StringIO
      StringIO.new gz.string
    end

    # un-gzips the given IO, returning the
    # decompressed version as a StringIO
    def ungzip(tarfile)
      z = Zlib::GzipReader.new(tarfile)
      unzipped = StringIO.new(z.read)
      z.close
      unzipped
    end

    # untars the given IO into the specified
    # directory
    def untar(io, destination)
      Gem::Package::TarReader.new io do |tar|
        tar.each do |tarfile|
          destination_file = File.join destination, tarfile.full_name

          if tarfile.directory?
            FileUtils.mkdir_p destination_file
          else
            destination_directory = File.dirname(destination_file)
            FileUtils.mkdir_p destination_directory unless File.directory?(destination_directory)
            File.open destination_file, "wb" do |f|
              f.print tarfile.read
            end
          end
        end
      end
    end
  end
end


### Usage Example: ###
#
# include Util::Tar
# 
# io = tar("./Desktop")   # io is a TAR of files
# gz = gzip(io)           # gz is a TGZ
# 
# io = ungzip(gz)         # io is a TAR
# untar(io, "./untarred") # files are untarred
#

Upvotes: 3

Mark Adler
Mark Adler

Reputation: 112617

First off, that will keep overwriting output.gz, leaving it containing only the last file compressed.

Second, the gzip format does not hold multiple files. It only holds one. You need to use the .tar.gz or .zip format. .zip is more "cross platform compatible". Take a look at rubyzip.

Upvotes: 2

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