Pipe in-to and out-of exiftool - no IO latency. Will add to a fork of mini_exiftool gem.

exiftool_stream

command = "exiftool -a -m -json -"
puts command.inspect

origin = Deckchair::Tempobject.new()
result = Deckchair::Tempobject.new()
origin.write File.read('./test.pdf')

IO.popen(command, 'rb+') do |pipe|
  pipe.puts origin.reread
  pipe.close_write
  
  while part = pipe.read(1024)
    result << part
  end
end


j = JSON.parse( result.reread )