TypeError：无法读取未定义的属性“插入用户名”

Question

当我尝试提交由 new.ejs 文件创建的登录表单时，我被重定向到有错误的页面，其中部分内容显示

无法读取未定义的属性“插入用户名”

此消息也会出现在控制台中。发生了什么，我该如何解决？

这是我的 idex.js

const express = require('express');
const app = express();
const routes = require('./routes');
const path = require('path');

const fileUpload = require('express-fileupload');
const bodyParser = require('body-parser');

const session = require('express-session');
const auth = require('./routes/auth');
const {
  con,
  sessionStore
} = require('./config/db');
const fs = require('fs');

require('dotenv').config({
  path: path.join(__dirname, '.env')
});
const port = process.env.PORT || 3000;



// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({
  extended: false
}));
// parse application/json
app.use(bodyParser.json());

//static files 
app.use(express.static('public'))
app.use('/css' , express.static(__dirname + 'public/css'))
app.use('/imgs' , express.static(__dirname + 'public/imgs'))

var sess = {
    secret: 'keyboard cat',
    store: sessionStore,
    cookie: {
      httpOnly: false,
    },
    resave: false,
    saveUninitialized: false
  }
  
  app.use(session(sess));
  app.use(fileUpload());
//set views
app.set('view engine' , 'ejs');
app.set('views', path.join(__dirname, 'views'));


app.use(require('connect-flash')());
app.use((req, res, next) => {
  res.locals.messages = require('express-messages')(req, res);
  next();
});
app.get('/', (req,res) =>{
    res.render('index22')
});
app.get('/login', (req, res) => {
    res.render('login');
   });

   let s;

const loginRequired = (req, res, next) => {
    if (req.session.username) {
    s = req.session;
    next();
    } else {
    res.redirect('/auth/login');
    }
};
app.get('/new', loginRequired, routes.new);//call for main index page
app.post('/', loginRequired, routes.new);//call for signup post 
app.get('/show/:username', loginRequired, routes.show);

routes.js

const {
   con,
   sessionStore
 } = require('./config/db');
exports.new = function(req, res){
    message = '';
   if(req.method == "POST"){
      const post  = req.body;
      const username= post.username;
      const title= post.title;
      const state= post.state;
      const category= post.category;
      const description= post.description;
 
      if (!req.files)
                return res.status(400).send('No files were uploaded.');
 
        const file = req.files.uploaded_image;
        const img_name=file.name;
 
         if(file.mimetype == "image/jpeg" ||file.mimetype == "image/png"||file.mimetype == "image/gif" ){
                                 
              file.mv('public/imgs/uploads/'+file.name, function(err) {
                             
                  if (err)
 
                    return res.status(500).send(err);
                        var sql = "INSERT INTO `nt_data`(`username`,`title`,`state`,`category`, `images` ,`description`) VALUES ('" + username + "','" + title + "','" + state + "','" + category + "','" + img_name + "','" + description + "')";
 
                            var query = con.query(sql, function(err, result) {
                                 res.redirect('show/'+result.insertUsername);
                            });
                       });
          } else {
            message = "This format is not allowed , please upload file with '.png','.gif','.jpg'";
            res.render('new.ejs',{message: message});
          }
   } else {
      res.render('new');
   }
 
};

exports.show = function(req, res){
    let message = '';
    var username = req.params.username;
    const sql="SELECT * FROM `nt_data` WHERE `username`='"+username+"'"; 
    con.query(sql, function(err, result){
      if(result.length <= 0)
      message = "show not found!";
      
      res.render('show.ejs',{data:result, message: message});
   });
};

Answer 1

您只能从SELECT 查询中获得结果，而不是INSERT、UPDATE 或DELETE。只需使用 username 变量中的用户名进行重定向。

另外，为查询中的变量数据使用占位符。

var sql = "INSERT INTO `nt_data`(`username`,`title`,`state`,`category`, `images` ,`description`) VALUES ?";
var query = con.query(sql, [username, title, state, category, img_name, description], function(err) {
  if (!err) {
    res.redirect('show/' + username);
  }
});