How to Generate Zip File Without Saving to the Disk with Ruby

How can I generate zip file without saving to the disk with Ruby?

I had a similar problem which I solved using the rubyzip gem and the stringio object.
It turns out that rubyzip provides a method that returns a stringio object: ZipOutputStream.write_buffer.

You can create the zip file structure as you like using put_next_entry and write and once you are finished you can rewind the stringio and read the binary data using sysread.

See the following simple example (works for rubyzip 0.9.X)

require 'zip/zip'
stringio = Zip::OutputStream.write_buffer do |zio|
  zio.put_next_entry("test.txt")
  zio.write "Hello world!"
end
stringio.rewind
binary_data = stringio.sysread

Tested on jruby 1.6.5.1 (ruby-1.9.2-p136) (2011-12-27 1bf37c2) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_29) [Windows Server 2008-amd64-java])

The following example works for rubyzip >= 1.0.0

require 'rubygems'    
require 'zip'
stringio = Zip::OutputStream.write_buffer do |zio|
  zio.put_next_entry("test.txt")
  zio.write "Hello world!"
end
binary_data = stringio.string

Tested on jruby 1.7.22 (1.9.3p551) 2015-08-20 c28f492 on OpenJDK 64-Bit Server VM 1.7.0_79-b14 +jit [linux-amd64] and rubyzip gem 1.1.7

Create zip archive without save archiving file to disk in Ruby

Found!

string_io = Zip::OutputStream.write_buffer do |zos|
  zos.put_next_entry(file_name)
  zos.write dictionary.join(', ')
end
# Rewind 
string_io.rewind
# Write simply to file in bin mode
IO.write("#{file_name}.zip", string_io.sysread)

How can I create a zip file without temporary files in ruby?

See the answer at "How can I generate zip file without saving to the disk with Ruby?"

I adapted your example to demonstrate it works.

require 'zip/zip'

zipname = 'test.zip'
File.delete(zipname) if File.exists?(zipname) #delete previous version

stringio = Zip::ZipOutputStream::write_buffer do |zio|
  1.upto(5) do |i| #Just some testfiles with content
    zio.put_next_entry("test#{i}.txt") #Filename
    zio.write("Testcontent %08i" % i)  #generated content
    sleep 1 #sleep some time to see the temporary files
  end
end
stringio.rewind #reposition buffer pointer to the beginning
File.new("test.zip","wb").write(stringio.sysread) #write buffer to zipfile

Rubyzip download attachments without creating the archive

This is the right syntax that made my code work 100% fine:

# Download zip file of all submission
  def download
    @submissions = Submission.all

    archiveFolder = Rails.root.join('tmp/archive.zip') #Location to save the zip

    # Delte .zip folder if it's already there
    FileUtils.rm_rf(archiveFolder)

    # Open the zipfile
    Zip::ZipFile.open(archiveFolder, Zip::ZipFile::CREATE) do |zipfile|
      @submissions.each do |filename|
        zipfile.add(filename.file_file_name, 'public/files/submissions/files/' + filename.id.to_s + '/original/' + filename.file_file_name)
      end
    end

    # Send the archive as an attachment
    send_file(archiveFolder, :type => 'application/zip', :filename => '2016 Submissions.zip', :disposition => 'attachment')
  end

rubyzip: open zip, modify it temporary, send to client

in the end i did it like this:

require 'zip'
zip_stream = Zip::OutputStream.write_buffer do |new_zip|

 existing_zip = Zip::File.open('existing.zip')
 existing_zip.entries.each do |e|
   new_zip.put_next_entry(e.name)
   new_zip.write e.get_input_stream.read
 end

 new_zip.put_next_entry 'new_file'
 new_zip.print "text"
end

Rubyzip: Export zip file directly to S3 without writing tmpfile to disk?

I think I just found the answer to my question.

It's Zip::ZipOutputStream.write_buffer. I'll check this out and update this answer when I get it working.

Update

It does work. My code is like this now:

compressed_filestream = Zip::ZipOutputStream.write_buffer do |zos|
  some_file_list.each do |file|
    zos.put_next_entry(file.some_title)
    zos.print IO.read(file.path)
  end
end # Outputs zipfile as StringIO

s3 = Aws::S3.new(S3_KEY, S3_SECRET)
bucket = Aws::S3::Bucket.create(s3, S3_BUCKET)

compressed_filestream.rewind
bucket.put("#{BUCKET_PATH}/archive.zip", compressed_filestream.read, {}, 'authenticated-read')

The write_buffer returns a StringIO and needs to rewind the stream first before reading it. Now I don't need to create and delete the tmpfile.

I'm just wondering now if write_buffer would be more memory extensive or heavier than open? Or is it the other way around?

Processing Zip files in Ruby

Hi I'm using rubyzip library. You can do something like this:

Zip::ZipFile.foreach(file) do |entry|
    istream = entry.get_input_stream
    data = istream.read
    #...
end

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