//authentication middleware.
function auth(req, res, next) {
  console.log(req.headers);
  var authHeader = req.headers.authorization;
  if(!authHeader) {
    var err = new Error('You are not authenticated');
    res.setHeader("WWW-Authenticate", 'Basic');
    err.status = 401;
    next(err);
  }
  var auth = new Buffer(authHeader.split(' ')[1], 'base64').toString().split(':');
  var username = auth[0];
  var password = auth[1];

  if(username === 'admin' && password === 'password') {
    next();
  }
  else {
    var err = new Error('Incorrect username/password');
    res.setHeader("WWW-Authenticate", 'Basic');
    err.status = 401;
    next(err);
  }
};
app.use(auth);