function ensureAuthenticated(req,res,next) {
  if (req.isAuthenticated()) { return next(); }
  res.redirect('/login')
}

app.get('/server',ensureAuthenticated,routes.server.get);
app.get('/login',routes.login.get);

或者像这样

app.all('*',function(req,next){
  if (req.path === '/' || req.path === '/login')
  next();
  else
  ensureAuthenticated(req,next);  
});