Node/Express JS "Cannot read property 'username' of undefined"

Question

在您将此标记为重复之前，请理解 none 我看过的答案与我的代码足够相关，可以解决问题。我正在尝试修复用于将文件从 Internet 上传到家庭服务器的 Web 应用程序中的错误。我目前正在研究基本的用户身份验证系统。当我尝试在主页上提交登录表单时，我被重定向到一个错误页面，其中一部分显示 "Cannot read property 'username' of undefined"。此消息也出现在控制台中。发生了什么事，我该如何解决？该错误将我引导至家庭控制器的第 8 行，"username = req.body.username"。 App.js

var LocalStrategy = require('passport-local').Strategy;
var flash = require("connect-flash");
var passport = require("passport");
var session = require("express-session");
var expressValidator = require("express-validator");
var mongoose = require("mongoose");
var path = require('path');
var express = require('express');
var cookieParser = require('cookie-parser');
var app = express();
var bodyParser = require('body-parser');
var ejs = require('ejs');
var routes = require('./server/routes');   
routes(app);
app.set('port', process.env.PORT || 3000);
app.use(bodyParser.urlencoded({extended: false}));
app.use(bodyParser.json());
app.use(express.static(path.join(__dirname, 'public')));
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');
app.use(cookieParser());
mongoose.connect("mongodb://localhost:27017/users");
app.listen(app.get('port'), function(){
  console.log("server started");
});
var db = mongoose.connection;
app.use(session({
  secret: 'yVVma9ga',
  saveUninitialized: true,
  resave: true
}));
app.use(passport.initialize());
app.use(passport.session());
app.use(expressValidator({
  errorFormatter: function(param, msg, value) {
      var namespace = param.split('.')
      , root    = namespace.shift()
      , formParam = root;

    while(namespace.length) {
      formParam += '[' + namespace.shift() + ']';
    }
    return {
      param : formParam,
      msg   : msg,
      value : value
    };
  }
}));
app.use(flash());
app.use(function(req,res,next) {
  res.locals.success_msg = req.flash('success_msg');
  res.locals.error_msg = req.flash('error_msg');
  res.locals.error = req.flash("error");
  next();
});

/server/routes.js

var express = require("express");
var home = require('../controllers/home');
var client = require('../controllers/client');
module.exports = function(app) {
    var router = express.Router();
    app.use('/', router);
    router.get('/', home.index);
    router.get('/client', client.home);
    router.post('/', home.login);
}

controllers/home.js

module.exports = {
    index: function(req, res){
        res.render("home");
    },
    login: function(req, res){
        var username = req.body.username;
        var password = req.body.password;
        req.checkBody('username', 'Username is required').notEmpty();
        req.checkBody('password', 'Password is required').notEmpty();
        var errors = req.validationErrors();
        if(errors){
            console.log("YES");
        }else{
            console.log("NO");
        };       
    }
}

/views/home.ejs（部分只是基本 html）

<% include partials/header %>
<p>Welcome to your personal server!</p>
<p>Login!</p>
<form method="post" action = "/">
<input placeholder="Username" type="text" name="username">
<input placeholder="Password" type="password" name="password">
<input type="submit" value="Submit">
</form>
<% include partials/footer %>

Answer 1

我敢打赌，您对路由的调用发生在 app.use 调用 bodyparser 之前。尝试将您的路线移到它们下方。

改变

var routes = require('./server/routes');   
routes(app);
//...
app.use(bodyParser.urlencoded({extended: false}));
app.use(bodyParser.json());

至

var routes = require('./server/routes');
//...
app.use(bodyParser.urlencoded({extended: false}));
app.use(bodyParser.json());
//...
routes(app);

Answer 2

var routes = require('./server/routes');

app.use(bodyParser.urlencoded({extended: false}));
app.use(bodyParser.json());
 //...
routes(app);

一切都应该在路线内。否则，您将遇到 undefined 错误。

Node/Express JS "Cannot read property 'username' of undefined"

Node/Express JS "Cannot read property 'username' of undefined"

node.js

express

login

passport.js

express-validator