我正在关注Udemy教程。到目前为止，一切都运行良好，直到我将应用程序连接到mongodb。应用程序运行正常，连接到数据库，但当我访问表单页面时，应用程序崩溃并给我以下错误。
app.js文件
var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var mongoose = require('mongoose');
var appRoutes = require('./routes/app');
var app = express();
mongoose.connect('localhost:27017/node-angular2');
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'hbs');
// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: false}));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
app.use(function (req, res, next) {
res.setHeader('Access-Control-Allow-Origin', '*');
res.setHeader('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept');
res.setHeader('Access-Control-Allow-Methods', 'POST, GET, PATCH, DELETE, OPTIONS');
next();
});
app.use('/', appRoutes);
// catch 404 and forward to error handler
app.use(function (req, res, next) {
return res.render('index');
});
module.exports = app;
路由器/ app.js
var express = require('express');
var router = express.Router();
var User = require('../models/user');
router.get('/', function (req, res, next) {
User.findOne({}, function(err, doc) {
if (err) {
return res.send('Error!');
}
res.render('node', {email: doc.email});
});
});
router.post('/', function(req, res, next) {
var email = req.body.email;
var user = new User({
firstName: 'Max',
lastName: 'Schwarz',
password: 'super-secret',
email: this.email
});
user.save();
res.redirect('/');
});
module.exports = router;
错误记录
> node ./bin/www
events.js:160
throw er; // Unhandled 'error' event
^
TypeError: Cannot read property 'email' of null
at /Users/farooqkhan/Documents/Udemy/node-angular2/routes/app.js:11:39
at Query.<anonymous> (/Users/farooqkhan/Documents/Udemy/node-angular2/node_modules/mongoose/lib/model.js:3381:16)
at /Users/farooqkhan/Documents/Udemy/node-angular2/node_modules/kareem/index.js:259:21
at /Users/farooqkhan/Documents/Udemy/node-angular2/node_modules/kareem/index.js:127:16
at _combinedTickCallback (internal/process/next_tick.js:67:7)
at process._tickCallback (internal/process/next_tick.js:98:9)
npm ERR! Darwin 16.1.0
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "start"
npm ERR! node v6.9.1
npm ERR! npm v3.10.8
npm ERR! code ELIFECYCLE
npm ERR! udemy-nodejs-angular2@1.0.0 start: `node ./bin/www`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the udemy-nodejs-angular2@1.0.0 start script 'node ./bin/www'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the udemy-nodejs-angular2 package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! node ./bin/www
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs udemy-nodejs-angular2
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! npm owner ls udemy-nodejs-angular2
npm ERR! There is likely additional logging output above.
npm ERR! Please include the following file with any support request:
npm ERR! /Users/farooqkhan/Documents/Udemy/node-angular2/npm-debug.log
第二个例子。
然后我运行了一个mongodb IDE，我是从github那里得到的。它过去工作正常但现在当我访问主页时它也会出现以下错误：
> node app.js
(node:1054) fs: re-evaluating native module sources is not supported. If you are using the graceful-fs module, please update it to a more recent version.
adminMongo listening on host: http://0.0.0.0:1234
GET / 302 8.496 ms - 56
/Users/farooqkhan/Documents/mongoIDE/adminMongo/node_modules/mongodb/lib/mongo_client.js:237
throw err
^
TypeError: Cannot read property 'indexOf' of undefined
at module.exports (/Users/farooqkhan/Documents/mongoIDE/adminMongo/node_modules/parse-mongo-url/index.js:10:10)
at new Database (/Users/farooqkhan/Documents/mongoIDE/adminMongo/node_modules/mongojs/lib/database.js:43:20)
at module.exports (/Users/farooqkhan/Documents/mongoIDE/adminMongo/node_modules/mongojs/index.js:5:12)
at /Users/farooqkhan/Documents/mongoIDE/adminMongo/routes/index.js:58:22
at connectCallback (/Users/farooqkhan/Documents/mongoIDE/adminMongo/node_modules/mongodb/lib/mongo_client.js:315:5)
at /Users/farooqkhan/Documents/mongoIDE/adminMongo/node_modules/mongodb/lib/mongo_client.js:234:11
at _combinedTickCallback (internal/process/next_tick.js:67:7)
at process._tickCallback (internal/process/next_tick.js:98:9)
npm ERR! Darwin 16.1.0
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "start"
npm ERR! node v6.9.1
npm ERR! npm v3.10.8
npm ERR! code ELIFECYCLE
npm ERR! admin-mongo@0.0.3 start: `node app.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the admin-mongo@0.0.3 start script 'node app.js'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the admin-mongo package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! node app.js
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs admin-mongo
npm ERR! Or if that isn't available, you can get their info via:
npm ERR! npm owner ls admin-mongo
npm ERR! There is likely additional logging output above.
npm ERR! Please include the following file with any support request:
npm ERR! /Users/farooqkhan/Documents/mongoIDE/adminMongo/npm-debug.log
我不明白这里有什么不对。一切都习以为常，我不知道突然发生了什么。我甚至尝试重新安装MongoDB，但没有任何帮助。
答案 0 :(得分：0)
看起来这个集合没有数据，你能验证你的node-angular2模块是否有用户表并且有数据吗？
您可以通过第三方工具（如robomongo）或通过shell连接mongo命令来执行此操作。
同时你可以修改你的代码来做一些错误处理
var express = require('express');
var router = express.Router();
var User = require('../models/user');
router.get('/', function (req, res, next) {
User.findOne({}, function(err, doc) {
if (err) {
return res.send('Error!');
}
if(doc){
res.render('node', {email: doc.email});
}else{
res.render('node', {email: null});
}
});
});
router.post('/', function(req, res, next) {
var email = req.body.email;
var user = new User({
firstName: 'Max',
lastName: 'Schwarz',
password: 'super-secret',
email: email
});
user.save(function(err){
if(err){
console.log("couldn't save");
}
res.redirect('/');
});
});
module.exports = router;
正如您所看到的，我已经修改了您的帖子，并且在保存功能的回调中调用了重定向，这意味着它将仅在用户保存时重定向。
当调用res.json或res.redirect而未完成上一个操作时，以前的操作将被固有地取消。