Node + Express + Passport: req.user未定义

const express = require('express');
const passport = require('passport');
const LocalStrategy = require('passport-local').Strategy;

const app = express();

// 配置Passport使用本地策略
passport.use(new LocalStrategy(
  function(username, password, done) {
    // 这里应该是查找用户的逻辑
    User.findOne({ username: username }, function (err, user) {
      if (err) { return done(err); }
      if (!user) { return done(null, false); }
      if (!user.verifyPassword(password)) { return done(null, false); }
      return done(null, user);
    });
  }
));

// 序列化和反序列化用户
passport.serializeUser(function(user, done) {
  done(null, user.id);
});

passport.deserializeUser(function(id, done) {
  User.findById(id, function(err, user) {
    done(err, user);
  });
});

// 使用Passport中间件
app.use(passport.initialize());
app.use(passport.session());

// 路由示例
app.post('/login', 
  passport.authenticate('local', { failureRedirect: '/login' }),
  function(req, res) {
    res.redirect('/');
  });

app.get('/', function(req, res) {
  if (req.isAuthenticated()) {
    res.send('Hello ' + req.user.username);
  } else {
    res.send('Please login');
  }
});

const session = require('express-session');

// 配置Session中间件
app.use(session({
  secret: 'your_secret_key',
  resave: false,
  saveUninitialized: false
}));

// 先加载Passport中间件
app.use(passport.initialize());
app.use(passport.session());

// 然后定义路由
app.post('/login', passport.authenticate('local', { failureRedirect: '/login' }), function(req, res) {
  res.redirect('/');
});

app.post('/login', 
  passport.authenticate('local', { 
    failureRedirect: '/login', 
    failureFlash: true 
  }),
  function(req, res) {
    res.redirect('/');
  });