} else { // the version that holds ratings in-memory
    res.writeHead(200, {'Content-type': 'application/json'})
    res.end(JSON.stringify(putLocalReviews(productId, ratings)))
  }
})

dispatcher.onGet(/^\/ratings\/[0-9]*/, function (req, res) {
  var productIdStr = req.url.split('/').pop()
  var productId = parseInt(productIdStr)