gistfile1.js

var http = require('http');
var express = require('express');
var app = express();

app.get('/my-form', function (req, res, next) {
  var form_data = req.flash('form_data');
  res.locals.form_data = form_data;
  
  var validation_errors = req.flash('validation_errors');
  res.locals.validation_errors = validation_errors;
  
  res.render('my-form');
});

app.post('/my-form/create', function (req, res, next) {

  if (validation_fails) {
    req.flash('form_data', req.body);
    req.flash('validation_errors', [ 'error 1', 'error 2'])
    return res.redirect('back');
  }

  db.save(req.body);
  res.redirect('/success');

});

http.createServer(app).listen(3000);