Send back the raw HTTP request (for elastic beanstalk, use node 6.2.2)

echo.js

require('http')
.createServer((req, res) => {
  let body = []
  req
  .on('data', chunk => body.push(chunk))
  .on('end', () => res.end(
    req.rawHeaders
    .filter((el, i) => i % 2 === 0)
    .reduce(
      (a, key, i) => a.concat(`${key}: ${req.rawHeaders[i * 2 + 1]}`),
      [`${req.method} ${req.url} HTTP/${req.httpVersion}`]
    )
    .concat(['', Buffer.concat(body).toString()])
    .join('\r\n')
  ))
})
.listen(8081)