[RAILS] If you want to make a zip file with Ruby, it's rubyzip.


I had to create a lot of zip files for a certain task, but I was saved by encountering this gem. This article introduces four ways to work with zip files using ruby.

Ruby version

Ruby 2.4 or higher

install gem

Add to Gemfile


gem 'rubyzip'

Run the following command in the terminal


bundle install

Use properly for 4 purposes

1. Create a zip file

Zip::OutputStream.open('example.zip') do |zos|
  zos.puts 'hoge hoge'

  zos.puts 'hoge again'

Use a string or the data read from the file as an argument to the puts method. The contents of the generated zip file have the following structure.

- first_file.txt
- second_file.txt

The contents of each file are as follows.


hoge hoge


hoge again

2. Read the zip file

The files in the zip file are set one after another by the get_next_entry method.

Zip::InputStream.open('example.zip') do |zis|
  entry = zis.get_next_entry
  print "First line of '#{entry.name} (#{entry.size} bytes):  "
  puts "'#{zis.gets.chomp}'"
  entry = zis.get_next_entry
  print "First line of '#{entry.name} (#{entry.size} bytes):  "
  puts "'#{zis.gets.chomp}'"

If you read the ʻexample.zip` generated in ** 1 **, you will see the following.


First line of 'first_file.txt (10 bytes):  hoge hoge
First line of 'second_file.txt (11 bytes):  hoge again

3. Read the zip file directory

Use the get_input_stream (entry) method to get the ʻInputStream` for each entry.

zf = Zip::File.new('example.zip')
zf.each_with_index do |entry, index|
  puts "entry #{index} is #{entry.name}, size = #{entry.size}, compressed size = #{entry.compressed_size}"

This source code displays the compressed files ʻindex, name, size, compressed_size` in a zip file.

If you read the ʻexample.zip` generated in ** 1 **, you will see the following.


entry 0 is first_file.txt, size = 10, compressed size = 10
entry 1 is second_file.txt, size = 11, compressed size = 13

4. Modify the zip file

Modify the zip file directly

Add the file indicated by path with ʻadd (entry, path) Rename withrename (entry, new_name)`

Modify the file generated by ** 1 **

Zip::File.open('example.zip') do |zip_file|
  zip_file.add('third_file.txt', 'third_file.txt')
  zip_file.rename('first_file.txt', 'first_file_rename.txt')
  zip_file.add('fourth_file.txt', 'fourth_file.txt')

The following files are additionally prepared.


hoge third


hogehoge fourth

I will try it. Get information using ** 3 **


entry 0 is second_file.txt, size = 11, compressed size = 13
entry 1 is third_file.txt, size = 10, compressed size = 12
entry 2 is first_file_rename.txt, size = 10, compressed size = 10
entry 3 is fourth_file.txt, size = 14, compressed size = 14

The generated zip file has been modified to have the following structure:

- second_file_txt
- third_file.txt
- first_file_rename.txt
- fourth_file.txt


In this article, I have introduced four ways to work with zip files. There are other useful methods in rubyzip, so it is recommended to take a look.



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