Develop Reference

How to connect node.js to MySQL

I am trying to connect node.js to MySQL and failed. I have installed MySQL and relevant libraries. How do I resolve this error? Also, if I want to get data to react-native, how should I go about doing it?
const express = require('express');
const mysql = require('mysql');
const connection = mysql.createPool({
host : '*****',//aws db endpoint/MySQL hostname
user : 'administrator', // username of MySQL connection
password : '*****', //pw of MySQL db
database : 'database_3' // name of database to be used
});
const app = express();
app.get('/User', function (req, res) {
connection.getConnection(function (err, connection) {
connection.query('SELECT * FROM User', function (error, results, fields) {
if (error) throw error;
res.send(results)
});
});
});
// Starting our server.
app.listen(3306, () => {
console.log('Go to http://localhost:3306/User');
});
The error msg received :
events.js:174
throw er; // Unhandled 'error' event
^
Error: listen EADDRINUSE: address already in use :::3306
at Server.setupListenHandle [as _listen2] (net.js:1279:14)
at listenInCluster (net.js:1327:12)
at Server.listen (net.js:1414:7)
at Function.listen (C:\Users\Irvin\my-new-project\node_modules\express\lib\application.js:618:24)
at Object.<anonymous> (C:\Users\Irvin\my-new-project\route.js:39:5)
at Module._compile (internal/modules/cjs/loader.js:778:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
at Module.load (internal/modules/cjs/loader.js:653:32)
at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
at Function.Module._load (internal/modules/cjs/loader.js:585:3)
Emitted 'error' event at:
at emitErrorNT (net.js:1306:8)
at process._tickCallback (internal/process/next_tick.js:63:19)
at Function.Module.runMain (internal/modules/cjs/loader.js:834:11)
at startup (internal/bootstrap/node.js:283:19)
at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)

Error: listen EADDRINUSE: address already in use :::3306
This means that the port 3306 is already in use, try changing it to another port or stop the process running on that port.
// Lets change 3306 to 3307
app.listen(3307, () => {
console.log('Go to http://localhost:3307/User');
});
If you want to stop the process on this port here is how to do it on linux

3306 is the default mysql port. Don't use that port for a server if you already have mysql running.
Don't stop the process on that port otherwise mysql will stop running, unless you're running it in another port, which is not your case.
app.listen(3000, () => {
console.log('Go to http://localhost:3306/User');
});

Hi since you are running mysql, it runs on port 3306 by default. Since you are tryung to start your express app on the same port, you get this error. You need to start your express application on any other port.

Your nodeJs application is using same port with MySQL .
// Starting our server.
app.listen(3306, () => {
console.log('Go to http://localhost:3306/User');
});
That app.listen(3306) is your nodeJs application listening port,
your current MySQL listening port is also 3306 ，
so your nodeJs application throw an error
Error: listen EADDRINUSE: address already in use :::3306
Means the port 3306 is already in use .
You should change your nodeJs application listening port like 8080 or 8090,
For example :
const express = require('express');
const mysql = require('mysql');
const connection = mysql.createPool({
host : '*****',//aws db endpoint/MySQL hostname
user : 'administrator', // username of MySQL connection
password : '*****', //pw of MySQL db
database : 'database_3' // name of database to be used
});
const app = express();
app.get('/User', function (req, res) {
connection.getConnection(function (err, connection) {
connection.query('SELECT * FROM User', function (error, results, fields) {
if (error) throw error;
res.send(results)
});
});
});
// change this port to 8090
app.listen(8090, () => {
console.log('Go to http://localhost:3306/User');
});

Unexpected Token ILLEGAL on running node.js

I'm doing a programming course and I'm trying to run the command node server.js. However this is the result I get.
node server.js
/home/lalitp/webapp/imad-app/server.js:26
console.log(`IMAD course app listening on port ${port}!`);
^
SyntaxError: Unexpected token ILLEGAL
at Module._compile (module.js:439:25)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Function.Module.runMain (module.js:497:10)
at startup (node.js:119:16)
at node.js:902:3
This is the server.js file:
var express = require('express');
var morgan = require('morgan');
var path = require('path');
var app = express();
app.use(morgan('combined'));
app.get('/', function (req, res) {
res.sendFile(path.join(__dirname, 'ui', 'index.html'));
});
app.get('/ui/style.css', function (req, res) {
res.sendFile(path.join(__dirname, 'ui', 'style.css'));
});
app.get('/ui/madi.png', function (req, res) {
res.sendFile(path.join(__dirname, 'ui', 'madi.png'));
});
// Do not change port, otherwise your app won't run on IMAD servers
// Use 8080 only for local development if you already have apache running on 80
var port = 80;
app.listen(port, function () {
console.log(`IMAD course app listening on port ${port}!`);
});
Thanks for the help :)

You are probably using an older version of Node.js, which does not support the so-called back-tick quoted strings (surrounded by the ` character).
If you change
console.log(`IMAD course app listening on port ${port}!`);
to
console.log('IMAD course app listening on port ' + port + '!');
it should work.
The back-tick quoted strings are for interpolating variables, i.e. integrating a JavaScript expression into a string. This makes long strings with lots of variables easier to read than concatenating every single bit by using the + operator.

It seems that you're using ES5 and not ES6 so you cannot use ` token for a string :
console.log('IMAD course app listening on port ${port}!');

Object #<MongoClient> has no method 'open'

I've been trying to make a simple site with Node.js, Express.js, and MongoDB. I'm new to these technologies and have been having problem set up the database
Here is snippet of code in my index.js file:
var http = require('http'),
express = require('express'),
path = require('path'),
MongoClient = require('mongodb').MongoClient,
Server = require('mongodb').Server,
CollectionDriver = require('./collectionDriver').CollectionDriver;
var app = express();
app.set('port', process.env.PORT || 3000);
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
var mongoHost = 'localHost';
var mongoPort = 27017;
var collectionDriver;
var mongoClient = new MongoClient(new Server(mongoHost, mongoPort));
mongoClient.open(function(err, mongoClient) {
if (!mongoClient) {
console.error("Error! Exiting... Must start MongoDB first");
process.exit(1);
}
var db = mongoClient.db("MyDatabase");
collectionDriver = new CollectionDriver(db);
});
After I try to run node index.js in terminal, it says the following:
js-bson: Failed to load c++ bson extension, using pure JS version
/Users/username/dev/ga-final/index.js:31
mongoClient.open(function(err, mongoClient) { //C
^
TypeError: Object #<MongoClient> has no method 'open'
at Object.<anonymous> (/Users/username/dev/ga-final/index.js:31:13)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Function.Module.runMain (module.js:497:10)
at startup (node.js:119:16)
at node.js:906:3
What is wrong? Why can't I call open? Can you help me fix this? thanks!

This is happening may be because you are using new version of mongodb it is working fine after I use mongodb driver version 1.4.
npm install mongodb#1.4.x

Take a look at the mongodb docs. Your mongoClient object is not what you think it is, and that why there isn't an open() method available.
Make your example code look more like theirs:
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
// Connection URL
var url = 'mongodb://localhost:27017/myproject';
// Use connect method to connect to the Server
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
console.log("Connected correctly to server");
db.close();
});

Cannot get my file to display through Node.js

I'm having problems with my node server. I'm trying to gather data from my coffees.js file which is in a routes folder by linking it to my server.js file. Both my server.js file and routes folder containg the coffees.js file are in my nodeservers folder. When I run the server.js (which is probably the problem as I think it is coded wrong) I get the following error:
Server running at http-00000000-:8080/
Listening on port 8080...
events.js:72
throw er; // Unhandled 'error' event
^
Error: listen EADDRINUSE
at errnoException (net.js:904:11)
at Server._listen2 (net.js:1042:14)
at listen (net.js:1064:10)
at Server.listen (net.js:1138:5)
at Function.app.listen (/node_modules/express/lib/application.js:533:24)
at Object.<anonymous> (/home/ec2-user/nodeservers/simpleserver.js:19:5)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
[ec2-user#ip-10-74-151-139 nodeservers]$ ^C
[ec2-user#ip-10-74-151-139 nodeservers]$
My simpleserver.js file looks like this:
// Load the http module to create an http server.
var http = require('http');
// Configure our HTTP server to respond with Hello World to all requests.
var server = http.createServer(function (request, response) {
response.writeHead(200, {"Content-Type": "text/plain"});
response.end("Hello World\n");
});
// Listen on port 8000, IP defaults to 127.0.0.1
server.listen(8080);
// Put a friendly message on the terminal
console.log("Server running at http://127.0.0.1:8080/");
var express = require('express'),
coffees = require('./routes/coffees');
var app = express();
app.get('/coffees', coffees.findAll);
app.get('/coffees/:id', coffees.findById);
app.listen(8080);
console.log('Listening on port 8080...');
Anyone able to tell me whats wrong?

Remove either
server.listen(8080) or app.listen(8080).
I think you want to use express, so remove the first.

Express has no method configure error

I'm trying to get started with the MEAN stack. And I'm following this tutorial: link
I have made it until the Test Our Server section. Here
// modules =================================================
var express = require('express');
var app = express();
var mongoose= require('mongoose');
// configuration ===========================================
// config files
var db = require('./config/db');
var port = process.env.PORT || 8080; // set our port
mongoose.connect(db.url); // connect to our mongoDB database (uncomment after you enter in your own credentials in config/db.js)
app.configure(function() {
app.use(express.static(__dirname + '/public')); // set the static files location /public/img will be /img for users
app.use(express.logger('dev')); // log every request to the console
app.use(express.bodyParser()); // have the ability to pull information from html in POST
app.use(express.methodOverride()); // have the ability to simulate DELETE and PUT
});
// routes ==================================================
require('./app/routes')(app); // configure our routes
// start app ===============================================
app.listen(port); // startup our app at http://localhost:8080
console.log('Magic happens on port ' + port); // shoutout to the user
exports = module.exports = app; // expose app
When I run
nodemon server.js
I get this error
app.configure(function() {
^
TypeError: Object function (req, res, next) {
app.handle(req, res, next);
} has no method 'configure'
at Object.<anonymous> (C:\Users\Yuksel\Desktop\node\test\server.js:14:5)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Function.Module.runMain (module.js:497:10)
at startup (node.js:119:16)
at node.js:902:3
5 Mar 17:27:20 - [nodemon] app crashed - waiting for file changes before startin
g...
It simply says app has no method configure(I guess). But when I delete the configure part and run it again, it works.(This mean app has .listen method, so it is an express object.)
I have tried with both node and nodemon. And I couldn't figure it out. Thank you for your time.

Tom in his blog post new-features-node-express-4 provides examples of how to convert from using app.configure in express version 3.x to removing it in express version 4.0.
For convenience I added the code example below.
Version 3.x
// all environments
app.configure(function(){
app.set('title', 'Application Title');
})
// development only
app.configure('development', function(){
app.set('mongodb_uri', 'mongo://localhost/dev');
})
// production only
app.configure('production', function(){
app.set('mongodb_uri', 'mongo://localhost/prod');
})
Version 4.0
// all environments
app.set('title', 'Application Title');
// development only
if ('development' == app.get('env')) {
app.set('mongodb_uri', 'mongo://localhost/dev');
}
// production only
if ('production' == app.get('env')) {
app.set('mongodb_uri', 'mongo://localhost/prod');
}

The configure method has been removed from express as of version 4.0.0 (including 4.0.0-rc2). See the changelog at https://github.com/strongloop/express/blob/master/History.md#400--2014-04-09