Lucky Middleware

example.js

var app = require('express')();
var luck = require('./luck-filter');
var prettyLucky = luck(0.6);
var reallyQuiteLucky = luck(0.9);

app.use('/blog', prettyLucky);
//bad luck is contagious; only allow luckiest of all users to contact you
app.use('/contact', prettyLucky);

luck-filter.js

/**
 * @param float 0-1 minimum luck threshold (higher = more lucky)
 *        default: .5
 */
module.exports = function(threshold){
  threshold = threshold || 0.5;
  return function luckyUsersOnly(req, res, next){
    if(Math.random() < threshold){
      res.status(403).send('Not Authorized (Unlucky User)');
    }
    else{
      next();
    }
  }
}