downgrading node.js permission after binding to port 80

server.js

var express = require('express');

var app = express.createServer();

app.set('view engine', 'jade');

app.set('port', parseInt(process.env.PORT || 5000, 10));

app.get('/', function(req, res) {
  res.render('index');
});

function showMessage() {
  console.log('Listening on port ' + app.set('port') + '...');
  if (app.set('port') == 80) {
    app.set('uid', process.env.NODE_UID || 'node');
  }
  process.setgid(app.set('uid'));
  process.setuid(app.set('uid'));
}

if (typeof process.env.ADDR !== 'undefined') {
  app.set('addr', process.env.ADDR);
  app.listen(app.set('port'), app.set('addr'), showMessage);
} else {
  app.listen(app.set('port'), showMessage);
}