Easy Zip Compression in Ruby

I needed a quick way of exporting data as zlib from a controller in Rails, so I came up with this:

def export
  send_data compress_string(Document.find_all.to_xml), :filename => 'backup.xml.gz'
end

def compress_string(data)
  gz = Zlib::GzipWriter.new(StringIO.new(''))
  gz.write data
  gz.close.string
rescue
  gz.close
  raise
end

Another way would be to use tempfiles with Tempfile — I wanted to benchmark and profile using files compared to StringIO, but that’ll be an exercise for another day.

This could also work nicely with Minitar.