TypeError：无法读取未定义的属性“查询”？

我正在尝试与Docker部署我的节点应用程序。这里是我的节点应用程序：

var express = require('express'); var path = require('path'); var mysql = require('mysql'); var app = express(); var bodyparser = require('body-parser'); var mongoose =require('mongoose'); app.use(express.static("./app")); var pool = mysql.createPool({ host: 'localhost', user: 'root', password: 'root', database: 'node_db' }); app.set('port',8080); app.set('views',path.join(__dirname,'views')); app.set('view engine','jade'); app.use(express.static(path.join(__dirname,'public'))); app.use(bodyparser.urlencoded({ extended: false })); app.get('/', function (req, res) { res.sendfile('app/index.html'); }); app.get('/getAllBlogs', function (req, res) { pool.getConnection(function (err, connection) { var sql = mysql.format("select * from blogs"); connection.query(sql, function (error, results, fields) { connection.release(); if (error) { res.send(error); } res.send(results); }); }); }); app.get('/getBlog/:id', function(req,res){ console.log(req.params.id); pool.getConnection(function (err, connection) { var sql = mysql.format("select * from blogs where id=?", [req.params.id]); connection.query(sql, function (error, results, fields) { connection.release(); if (error) { res.status(200).send(error); } res.send(results[0]) }); }); }); app.listen(app.get('port')); console.log('~~Server Runnign on port localhost:'+app.get('port')+'~~'); 

这是我的Docker文件：

 FROM node:boron # Create app directory RUN mkdir -p /home/sameera/Desktop/test/app WORKDIR /home/sameera/Desktop/test/app # Install app dependencies COPY package.json /home/sameera/Desktop/test/app RUN npm install # Bundle app source COPY . /home/sameera/Desktop/test/app EXPOSE 8080 CMD [ "npm", "start" ] 

docker文件build立成功，当我运行下面的命令它正常运行。

 docker run -p 49160:8080 img 

但是，当我尝试加载使用MySQL数据的页面时，它给出了一个错误：

  connection.query(sql, function (error, results, fields) { ^ TypeError: Cannot read property 'query' of undefined } 

我想这个问题是因为我不能连接到这个容器的MySQL，因为我没有安装或在docker文件中使用任何mysql相关的命令。当我删除所有我的SQL连接和相关的代码它不会给出任何错误和运行好，我正在使用Ubuntu 14.04

Answer 1

如果不需要池，则可以使用以下代码：

 var express = require('express'); var path = require('path'); var mysql = require('mysql'); var app = express(); var bodyparser = require('body-parser'); var mongoose = require('mongoose'); app.use(express.static("./app")); var pool = mysql.createConnection({ host: 'localhost', user: 'root', password: 'root', database: 'node_db' }); pool.connect(); app.set('port', 8080); app.set('views', path.join(__dirname, 'views')); app.set('view engine', 'jade'); app.use(express.static(path.join(__dirname, 'public'))); app.use(bodyparser.urlencoded({ extended: false })); app.get('/test', function (req, res) { var sql = mysql.format("SELECT * FROM users"); pool.query(sql, function (error, results, fields) { if (error) { res.send(error); } res.send(results); pool.end(); }); }); app.listen(app.get('port')); console.log('Server Runnign on port localhost:' + app.get('port')); 

结果会是这样的：

 [ { "id": 1, "firstName": "shubham", "lastName": "verma", "userName": "shubham", "email": "[e-mail]", "password": "25d55ad283aa400af464c76d713c07ad", "sessionId": "bdfb43ae-ee9e-4819-b35a-3cb254885023", "isLive": 1, "date": "2017-05-06T06:05:24.000Z" } ] 

但是，如果池是必要的，你想使用池，那么你应该尝试下面的代码：

 var express = require('express'); var path = require('path'); var mysql = require('mysql'); var app = express(); var bodyparser = require('body-parser'); var mongoose = require('mongoose'); app.use(express.static("./app")); var pool = mysql.createPool({ connectionLimit: 10, host: 'localhost', user: 'root', password: 'root', database: 'node_db' }); app.set('port', 8080); app.set('views', path.join(__dirname, 'views')); app.set('view engine', 'jade'); app.use(express.static(path.join(__dirname, 'public'))); app.use(bodyparser.urlencoded({ extended: false })); app.get('/test', function (req, res) { pool.getConnection(function (err, connection) { var sql = mysql.format("SELECT * FROM users"); connection.query(sql, function (error, results, fields) { if (error) { res.send(error); } res.send(results); connection.release(); }); }); }); app.listen(app.get('port')); console.log('Server Runnign on port localhost:' + app.get('port')); 

结果将会是这样的：

 [ { "id": 1, "firstName": "shubham", "lastName": "verma", "userName": "shubham", "email": "[e-mail]", "password": "25d55ad283aa400af464c76d713c07ad", "sessionId": "bdfb43ae-ee9e-4819-b35a-3cb254885023", "isLive": 1, "date": "2017-05-06T06:05:24.000Z" } ] 

Answer 2

您正在使用池来连接到MySQL和查询连接。

使用池查询：

 var mysql = require('mysql'); var pool = mysql.createPool({ connectionLimit : 10, host : 'example.org', user : 'bob', password : 'secret', database : 'my_db' }); pool.query('SELECT 1 + 1 AS solution', function (error, results, fields) { if (error) throw error; console.log('The solution is: ', results[0].solution); });