DIY file encryption

lib_crypt.js

#!/opt/node/bin/node
// ~/bin/lib_crypt.js

const fs    = require('fs')
const spawn = require('child_process').spawn

const SUCCESS = 0

function in_out_file(direction, base_file_name) {
  const file_arr = [base_file_name + '.enc', base_file_name + '.txt']
  return (direction == 'en') ? file_arr.reverse() : file_arr
}

function crypt_args(direction, base_file_name) {
  let [in_file, out_file] = in_out_file(direction, base_file_name)
  const base_opts = ['enc', '-aes-256-cbc', '-in', in_file, '-out', out_file]
  const extra = (direction == 'en') ? ['-salt'] : ['-d']
  return base_opts.concat(extra)
}

function crypt(direction, base_file_name) {
	const command = spawn('/usr/bin/openssl', crypt_args(direction, base_file_name))
  const [in_file, out_file] = in_out_file(direction, base_file_name) 
  command.stdin.pipe(process.stdin);
  command.stdout.pipe(process.stdout);
  command.stderr.pipe(process.stderr);
  command.on('exit', function (code) {
    if (code == SUCCESS) {
      fs.unlinkSync(in_file)
      spawn('/bin/chmod', ['600', out_file])
    }
  });
}

module.exports = crypt