sample.js

exports.bufferOrderFile = function (req) {
  const d = exports.createDeferred()

  var name
  const data = []

  // Capture errors but intentially resolve to undefined
  const captureErAndRes = er => { log.err(er); d.resolve() }

  try {
    const busboy = new Busboy({
      headers: req.headers,
      limits: {
        fields: 0,        // No fields will be parsed
        files: 1,         // Any file after the first will be drained
        fileSize: 1000000 // 1 MB upload limit
      }
    })

    busboy.once('file', (field, rstream, filename) => {
      name = filename
      rstream.on('data', buffer => data.push(buffer))
      rstream.once('error', captureErAndRes)
    })

    busboy.once('error', captureErAndRes)
    busboy.once('finish', _ => d.resolve({ name, buffer: Buffer.concat(data) }))

    req.pipe(busboy)
  }
  catch (er) { captureErAndRes(er) }

  return d.promise
}