我正在開發一個 Node.js Express 和 MongoDB 網路應用程式。
實際上，我正在嘗試使用 MVC 功能。但是，在我將更新功能添加到模型之后，我的代碼出現了問題。
實際上，當我嘗試更新帖子時，我的應用程式崩潰了，并且收到以下錯誤訊息：
TypeError: C:\Users\DELL\Desktop\node-com4muz-database-mvc\views\admin\posts-list.ejs:19
17| <ol id="posts-list">
18| <% for (const post of posts) { %>
>> 19| <li><%- include('includes/post-item', { post: post }) %></li>
20| <% } %>
21| </ol>
22| <% } %>
C:\Users\DELL\Desktop\node-com4muz-database-mvc\views\admin\includes\post-item.ejs:3
1| <article >
2| <h2><%= post.title %></h2>
>> 3| <p >Rédigé par <%= post.author.name %></p>
4| <p><%= post.summary %></p>
5| <div >
6| <form action="/blog/<%= post._id %>/delete" method="POST">
Cannot read properties of undefined (reading 'name')
at eval ("C:\\Users\\DELL\\Desktop\\node-com4muz-database-mvc\\views\\admin\\includes\\post-item.ejs":15:38)
at post-item (C:\Users\DELL\Desktop\node-com4muz-database-mvc\node_modules\ejs\lib\ejs.js:703:17)
at include (C:\Users\DELL\Desktop\node-com4muz-database-mvc\node_modules\ejs\lib\ejs.js:701:39)
at eval ("C:\\Users\\DELL\\Desktop\\node-com4muz-database-mvc\\views\\admin\\posts-list.ejs":29:17)
at posts-list (C:\Users\DELL\Desktop\node-com4muz-database-mvc\node_modules\ejs\lib\ejs.js:703:17)
at tryHandleCache (C:\Users\DELL\Desktop\node-com4muz-database-mvc\node_modules\ejs\lib\ejs.js:274:36)
at View.exports.renderFile [as engine] (C:\Users\DELL\Desktop\node-com4muz-database-mvc\node_modules\ejs\lib\ejs.js:491:10)
at View.render (C:\Users\DELL\Desktop\node-com4muz-database-mvc\node_modules\express\lib\view.js:135:8)
at tryRender (C:\Users\DELL\Desktop\node-com4muz-database-mvc\node_modules\express\lib\application.js:657:10)
at Function.render (C:\Users\DELL\Desktop\node-com4muz-database-mvc\node_modules\express\lib\application.js:609:3) {
path: 'C:\\Users\\DELL\\Desktop\\node-com4muz-database-mvc\\views\\admin\\posts-list.ejs'
}
實際上，在我更改模型檔案（見下文）和路由檔案（見下文）中的代碼之前，更新功能運行良好。
這就是為什么我認為我們應該在將更新功能添加到模型之前和之后比較這兩種代碼以找出問題所在的原因。
這是我在將更新功能添加到模型之前的代碼：
路線\管理\博客.js：
const express = require('express');
const mongodb = require('mongodb');
const multer = require('multer');
const storageConfig = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, 'public/admin/images');
},
filename: function (req, file, cb) {
cb(null, Date.now() '-' file.originalname);
}
});
const db = require('../../data/database');
const Post = require('../../models/post');
const ObjectId = mongodb.ObjectId;
const upload = multer({ storage: storageConfig });
const router = express.Router();
router.get('/posts', async function (req, res) {
const posts = await db
.getDb()
.collection('posts')
.find({})
.project({ title: 1, summary: 1, 'author.name': 1 })
.toArray();
res.render('posts-list', { posts: posts });
});
router.get('/new-post', async function (req, res) {
const authors = await db.getDb().collection('authors').find().toArray();
res.render('create-post', { authors: authors });
});
router.post('/new-post', upload.single('image'), async function (req, res) {
const uploadedImageFile = req.file;
const authorId = new ObjectId(req.body.author);
const author = await db
.getDb()
.collection('authors')
.findOne({ _id: authorId });
const enteredTitle = req.body.title;
const enteredSummary = req.body.summary;
const enteredContent = req.body.content;
const date = new Date();
const selectedAuthor = {
author: {
id: authorId,
name: author.name,
email: author.email
}
};
const selectedImage = uploadedImageFile.path;
const post = new Post(
enteredTitle,
enteredSummary,
enteredContent,
date,
selectedAuthor.author,
selectedImage
);
await post.save();
res.redirect('/posts');
});
router.get('/blog/:id/edit', async function (req, res) {
const postId = req.params.id;
const post = await db
.getDb()
.collection('posts')
.findOne(
{ _id: new ObjectId(postId) },
{ title: 1, summary: 1, content: 1 }
);
if (!post) {
return res.status(404).render('404');
}
res.render('update-post', { post: post });
});
router.post('/blog/:id/edit', async function (req, res) {
const postId = new ObjectId(req.params.id);
const result = await db
.getDb()
.collection('posts')
.updateOne(
{ _id: postId },
{
$set: {
title: req.body.title,
summary: req.body.summary,
content: req.body.content
// date: new Date()
}
}
);
res.redirect('/posts');
});
router.post('/blog/:id/delete', async function (req, res) {
const postId = new ObjectId(req.params.id);
const result = await db
.getDb()
.collection('posts')
.deleteOne({ _id: postId });
res.redirect('/posts');
});
router.get('/admin', async function (req, res) {
if (!res.locals.isAuth) {
// if (!req.session.user)
return res.status(401).render('401');
}
if (!res.locals.isAdmin) {
return res.status(403).render('403');
}
res.render('admin');
});
module.exports = router;
模型\post.js：
const db = require('../data/database');
class Post {
constructor(title, summary, content, date, author, image, id) {
this.title = title;
this.summary = summary;
this.content = content;
this.date = date;
this.author = author;
this.image = image;
this.id = id; // may be undefined
}
async save() {
const newPost = {
title: this.title,
summary: this.summary,
content: this.content,
date: this.date,
author: this.author,
imagePath: this.image
};
const result = await db.getDb().collection('posts').insertOne(newPost);
// console.log(result);
return result;
}
}
module.exports = Post;
這是向模型添加更新功能后的代碼：
路線\管理\博客.js：
const express = require('express');
const mongodb = require('mongodb');
const multer = require('multer');
const storageConfig = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, 'public/admin/images');
},
filename: function (req, file, cb) {
cb(null, Date.now() '-' file.originalname);
}
});
const db = require('../../data/database');
const Post = require('../../models/post');
const ObjectId = mongodb.ObjectId;
const upload = multer({ storage: storageConfig });
const router = express.Router();
router.get('/posts', async function (req, res) {
const posts = await db
.getDb()
.collection('posts')
.find({})
.project({ title: 1, summary: 1, content: 1, 'author.name': 1 })
.toArray();
res.render('posts-list', { posts: posts });
});
router.get('/new-post', async function (req, res) {
const authors = await db.getDb().collection('authors').find().toArray();
res.render('create-post', { authors: authors });
});
router.post('/new-post', upload.single('image'), async function (req, res) {
const uploadedImageFile = req.file;
const authorId = new ObjectId(req.body.author);
const author = await db
.getDb()
.collection('authors')
.findOne({ _id: authorId });
const enteredTitle = req.body.title;
const enteredSummary = req.body.summary;
const enteredContent = req.body.content;
const date = new Date();
const selectedAuthor = {
author: {
id: authorId,
name: author.name,
email: author.email
}
};
const selectedImage = uploadedImageFile.path;
const post = new Post(
enteredTitle,
enteredSummary,
enteredContent,
date,
selectedAuthor.author,
selectedImage
);
await post.save();
res.redirect('/posts');
});
router.get('/blog/:id/edit', async function (req, res) {
const postId = req.params.id;
const post = await db
.getDb()
.collection('posts')
.findOne(
{ _id: new ObjectId(postId) },
{ title: 1, summary: 1, content: 1 }
);
if (!post) {
return res.status(404).render('404');
}
res.render('update-post', { post: post });
});
router.post('/blog/:id/edit', async function (req, res) {
const enteredTitle = req.body.title;
const enteredSummary = req.body.summary;
const enteredContent = req.body.content;
const post = new Post(
enteredTitle,
enteredSummary,
enteredContent,
req.params.id
);
await post.save();
res.redirect('/posts');
});
router.post('/blog/:id/delete', async function (req, res) {
const postId = new ObjectId(req.params.id);
const result = await db
.getDb()
.collection('posts')
.deleteOne({ _id: postId });
res.redirect('/posts');
});
router.get('/admin', async function (req, res) {
if (!res.locals.isAuth) {
// if (!req.session.user)
return res.status(401).render('401');
}
if (!res.locals.isAdmin) {
return res.status(403).render('403');
}
res.render('admin');
});
module.exports = router;
模型\post.js：
const mongodb = require('mongodb');
const db = require('../data/database');
const ObjectId = mongodb.ObjectId;
class Post {
constructor(title, summary, content, date, author, image, id) {
this.title = title;
this.summary = summary;
this.content = content;
this.date = date;
this.author = author;
this.image = image;
if (id) {
this.id = new ObjectId(id);
}
}
async save() {
let result;
if (this.id) {
result = await db
.getDb()
.collection('posts')
.updateOne(
{ _id: postId },
{
$set: {
title: this.id,
summary: this.summary,
content: this.content
}
}
);
} else {
result = await db.getDb().collection('posts').insertOne({
title: this.title,
summary: this.summary,
content: this.content,
date: this.date,
author: this.author,
imagePath: this.image
});
}
return result;
}
}
module.exports = Post;
uj5u.com熱心網友回復：
id在路由下創建post物件時，您將錯誤的引數傳遞給/blog/:id/edit它，它不會被拾取，因此它會保存帖子，而不是更新它，從而使其他屬性未定義。
試試這個，在 之前傳遞 3 個未定義的引數，它作為路由id下的最后一個引數傳遞：/blog/:id/edit
const post = new Post(
enteredTitle,
enteredSummary,
enteredContent,
...[,,,], // pass 3 undefined arguments
req.params.id
);
await post.save();
轉載請註明出處，本文鏈接：https://www.uj5u.com/caozuo/536453.html
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