nodejs在学习使用jade模板、express框架及与mongodb数据库进行交互，做一个用户验证网站时遇到问题？

网站能够正常连接数据库，各项配置应该均正确，但是在注册用户时无法保存至数据库并出现了如下问题，不太明白哪里undefined了。

E:\code\user-auth-example\node_modules\mongodb\lib\utils.js:98    process.nextTick(function() { throw err; });                                  ^TypeError: Cannot read property 'email' of undefined    at E:\code\user-auth-example\server.js:38:34    at E:\code\user-auth-example\node_modules\mongodb\lib\collection.js:525:5    at E:\code\user-auth-example\node_modules\mongodb\lib\collection.js:703:5    at handleCallback (E:\code\user-auth-example\node_modules\mongodb\lib\utils.js:95:56)    at executeCommands (E:\code\user-auth-example\node_modules\mongodb\lib\bulk\ordered.js:398:12)    at resultHandler (E:\code\user-auth-example\node_modules\mongodb\lib\bulk\ordered.js:425:5)    at E:\code\user-auth-example\node_modules\mongodb-core\lib\connection\pool.js:455:18    at _combinedTickCallback (internal/process/next_tick.js:67:7)    at process._tickCallback (internal/process/next_tick.js:98:9)    

然后下面是代码，比较多，package.json, express按照书上的方法用的是旧版本:

{    "name":"user-auth-example",    "version":"0.0.1",    "dependencies":{        "express":"2.5.8",        "mongodb":"2.2.24",        "jade":"0.31.2"    }}

server.js:

var express=require('express'),Db = require('mongodb').Db,Server = require('mongodb').Serverapp=express.createServer();var db = new Db('test01', new Server('localhost', 27017));db.open(function(err,client){    if(err)        throw err;    console.log('\033[96m  + \033[39m connected to mongodb');    app.users=db.collection('users');    app.listen(3000,function(){        console.log('\033[96m  + \033[39m app listening on *:3000');    });});app.use(express.bodyParser());app.use(express.cookieParser());app.use(express.session({secret:'my secret'}));app.set('view engine','jade');app.set('view options',{layout:false});app.get('/',function(req,res){    res.render('index',{authenticated:false});});app.get('/login/:signupEmail?', function (req, res) {  res.render('login', { signupEmail: req.params.signupEmail });});app.get('/signup',function(req,res){    res.render('signup');});app.post('/signup', function (req, res, next) {  app.users.insert(req.body.user, {safe:true}, function(err,doc) {    if (err) return next(err);    res.redirect('/login/'+doc[0].email);  });});

四个放在当前目录下views文件夹的jade，laydout.jade:

doctype 5html  head    title MongoDB example  body    h1 My first MongoDB app    hr    block body

index.jade:

include layoutblock bodyif (authenticated)  p Welcome back, #{me.name}  a(href="/logout") Logoutelse  p Welcome new visitor!  ul    li: a(href="/login") Login    li: a(href="/signup") Signup

login.jade:

include layoutblock bodyif (signupEmail)  p Congratulations on signingup! Please login below.form(action="/login", method="POST")  fieldset    legend Log in    p      label Email      input(name="user[email]", type="text", value=signupEmail)    p      label Password      input(name="user[password]", type="password")    p      button Submit    p      a(href="/") Go back

signup.jade:

include layoutblock bodyform(action="/signup", method="POST")  fieldset    legend Sign up    p      label First      input(name="user[first]", type="text")    p      label Last      input(name="user[last]", type="text")    p      label Email      input(name="user[email]", type="text")    p      label Password      input(name="user[password]", type="password")    p      button Submit    p      a(href="/") Go back      

最后吐槽一下Smashing Node.js这本书，真的太多错误了。然后若有大神能够回答此问题真的感激不敬！