node.js - TypeError : Object # has no method 'flash' error in node. js 即使在安装 connect-flash 之后

Question

作为初学者，我正在尝试使用 node.js 并尝试运行登录/身份验证，但卡住了。然后我使用 npm 下载了 connect-flash 中间件，这就是我的 server.js 的样子:

var express = require('express'),
    passport = require('passport'),
    util = require('util'),
    LocalStrategy = require('passport-local').Strategy,
    wines = require('./routes/wines');

var users = [
    { id: 1, username: 'bob', password: 'secret', email: 'bob@example.com' }
  , { id: 2, username: 'joe', password: 'birthday', email: 'joe@example.com' }
];

function findById(id, fn) {
  var idx = id - 1;
  if (users[idx]) {
    fn(null, users[idx]);
  } else {
    fn(new Error('User ' + id + ' does not exist'));
  }
}

function findByUsername(username, fn) {
  for (var i = 0, len = users.length; i < len; i++) {
    var user = users[i];
    if (user.username === username) {
      return fn(null, user);
    }
  }
  return fn(null, null);
}

// Passport session setup.
//   To support persistent login sessions, Passport needs to be able to
//   serialize users into and deserialize users out of the session.  Typically,
//   this will be as simple as storing the user ID when serializing, and finding
//   the user by ID when deserializing.
passport.serializeUser(function(user, done) {
  done(null, user.id);
});

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



// Use the LocalStrategy within Passport.
//   Strategies in passport require a `verify` function, which accept
//   credentials (in this case, a username and password), and invoke a callback
//   with a user object.  In the real world, this would query a database;
//   however, in this example we are using a baked-in set of users.
passport.use(new LocalStrategy(
  function(username, password, done) {
    // asynchronous verification, for effect...
    process.nextTick(function () {

      // Find the user by username.  If there is no user with the given
      // username, or the password is not correct, set the user to `false` to
      // indicate failure and set a flash message.  Otherwise, return the
      // authenticated `user`.
      findByUsername(username, function(err, user) {
        if (err) { return done(err); }
        if (!user) { return done(null, false, { message: 'Unknown user ' + username }); }
        if (user.password != password) { return done(null, false, { message: 'Invalid password' }); }
        return done(null, user);
      })
    });
  }
));


var flash = require('connect-flash');
var express = require("express");
var app = express();


app.get('/', function(req, res){
  res.render('index', { user: req.user });
});

app.get('/flash', function(req, res){
  req.flash('info', 'Flash is back!')
  res.redirect('/');
});

app.get('/account', ensureAuthenticated, function(req, res){
  res.render('account', { user: req.user });
});

app.get('/login', function(req, res){
  res.render('login', { user: req.user, message: "Hello!"});
});



// configure Express
app.configure(function() {
  app.set('views', __dirname + '/views');
  app.set('view engine', 'ejs');
  app.use(express.logger());
  app.use(express.cookieParser());
  app.use(express.bodyParser());
  app.use(express.methodOverride());
  app.use(express.session({ secret: 'keyboard cat' }));
  // Initialize Passport!  Also use passport.session() middleware, to support
  // persistent login sessions (recommended).
  app.use(passport.initialize());
  app.use(passport.session());
  app.use(app.router);
  app.use(express.cookieParser('keyboard cat'));
  app.use(express.session({ cookie: { maxAge: 60000 }}));
  app.use(flash());

});

// POST /login
//   Use passport.authenticate() as route middleware to authenticate the
//   request.  If authentication fails, the user will be redirected back to the
//   login page.  Otherwise, the primary route function function will be called,
//   which, in this example, will redirect the user to the home page.
//
//   curl -v -d "username=bob&password=secret" http://127.0.0.1:3000/login
app.post('/login', 
  passport.authenticate('local', { failureRedirect: '/login', failureFlash: true }),
  function(req, res) {
    res.redirect('/');
  });


app.get('/logout', function(req, res){
  req.logout();
  res.redirect('/');
});

app.listen(3000);


// Simple route middleware to ensure user is authenticated.
//   Use this route middleware on any resource that needs to be protected.  If
//   the request is authenticated (typically via a persistent login session),
//   the request will proceed.  Otherwise, the user will be redirected to the
//   login page.
function ensureAuthenticated(req, res, next) {
  if (req.isAuthenticated()) { return next(); }
  res.redirect('/login')
}
app.get('/wines', wines.findAll);
app.get('/wines/:id', wines.findById);


console.log('Listening on port 3000...');

为什么我仍然会收到该错误？如何解决？

Answer 1

将所有app[METHOD] 中间件移动到所有app.use 中间件之后