Connecting to a remote MySQL database from Stackblitz Node.js project - mysql

I have a Node.js Stackblitz project that I am trying to connect to a remote MySQL database. It is not possible to have a MySQL database within Stackblitz, hence trying the remote approach. However I get "Error: connect ETIMEDOUT" whenever I attempt a connection. Any help or pointers much appreciated.
I am using the code below. The remote database is accessible with the credentials I am using and returning data when used outside of Stackblitz. Is remote database access not possible with Stackblitz or am I missing something?
const express = require('express');
const mysql = require('mysql2/promise');
const app = express();
const port = 3010;
const path = require('path');
app.use(express.static('static'));
app.get('/', async function (req, res) {
try {
// create connection
const connection = await mysql.createConnection({
host: process.env.DB_HOST,
port: process.env.DB_PORT,
database: process.env.DB_DATABASE,
user: process.env.DB_USER,
password: process.env.DB_PASSWORD,
});
// query database
const [rows, fields] = await connection.execute('SELECT * FROM `user`');
res.send({
rows,
fields,
});
} catch (err) {
console.log('err:', err);
}
});
app.listen(port, () => {
console.log(`Example app listening at http://localhost:${port}`);
});

For anyone looking for an explanation.
Currently a mysql database cannot reside in StackBlitz. Additionally, neither can it connect to an external mysql database on its own either.
You therefore required a backend API outside of StackBlitz to make the database calls, negating the reason for building the backend on StackBlitz in the first place (IMO). Therefore, the suggested setup currently would be a localhost backend API accessed from a frontend in StackBlitz via an ngrok secure address.
StackBlitz are working on getting basic server requests running in the future. So, watch this space.
I hope this answer helps save others time.

Related

Is it possible to use express.js to build rest api in frontend?

the plan is to build the web app with react.js and also build the backend using express.js specfically using rest api to connec to mySQL database....the problem is
for authentication, my supervisor doesnt want me to store password anywhere, instead he suggested me to build an authentication using the usename and password that we use to connect to mySQL database. For example, when i try to make a connection with mysqlCreateConnection method, theres a section where i have to fill out the ip address and username and password. the problem is if i do this, when the user logs out, the connection between backend and database will disconnect......
is it possible to use mySQL createconnection in the front end? so whenever the user logs in it will connect to the database directly from the frontend? once the connection is created, then use backend rest api? if this works i assume the rest api has to be hosted with the same url as the frontend, since we made the connection to mySQL database in the frontend.......but again if we do this, doesnt it defeat the purpose of backend? meaning anyone can login to the frontend and change whatever they want to the backend?
so the result will be like
within the frontend. user logs in using mySQL workbench username and password, then that username and password is going to fill out the mysql createconnection method(this method is written in the frontend). which will then try to connect to the database.
user logs in successfull
user fills out a form about a product and clicks on submit and this data is send to our rest api, and mySQL database adds the data in.
here are examples of router-token and router-session within the app if you are at express.js.
db.js
const mysql = require("mysql2")
const config = require("../../config/config.json").DB
module.exports = mysql.createPool({
host: config.host,
user: config.username,
password: config.password,
database: config.database,
waitForConnections: true,
connectionLimit: 100,
queueLimit: 0,
multipleStatements: true
})
db.fun.js
const db = require("./db").promise()
let query = async(sql, data) => {
try {
let d = await db.query(sql, data);
return d[0];
} catch (err) {
console.log(`EDB: ./app/database/db.fun.js 8rows \n${err}`);
return { err: 1, errdata: err };
}
}
module.exports = {
query: query
}
import query
(async function(){
const { query } = require("../database/db.fun");
let user = await query("SELECT * FROM users",[]);
console.log(user)
})();

How to connect to my remote MySQL database from my Heroku NodeJS app?

I have a NodeJs backend hosted on Heroku. I am trying to connect to my remote MySQL database that is hosted under my Hostwinds plan. When I tried to connect to the DB in my local environment it worked perfectly, but when I deployed my app to Heroku I get an error saying Error: ER_ACCESS_DENIED_ERROR: Access denied for user 'myUserName'#'someRandomIP' (using password: YES).
I have added my Heroku URL to my remote access pannel in cPanel, but that didn't give the user access. I have also tried to add the someRandomIP to the remote access pannel in cPanel, but the weird thing about that IP is that is changes on every deploy/re-deploy. I am positive that my connection string is correct, but just in case: mysql://username:password#ipOfHost/dbName.
Here is my serverside code:
const express = require("express");
const app = express();
const cors = require("cors");
const mysql = require("MySQL");
const { resolve } = require("path");
const stripe = require("stripe")(process.env.STRIPE_PRIVATE_API_KEY);
// enable CORS
app.use(cors({
origin: 'http://localhost:3000'
}))
// form connection object
var connection = mysql.createConnection(process.env.DATABASE_URL);
// connect to the database
connection.connect(function(err) {
if (err) throw err;
console.log("You are connected to the database");
})
app.listen(4242, () => console.log('Node server listening on oneline-backend.herokuapp.com'));
Here is a link to the full error in the Heroku Console: https://i.imgur.com/QXfEVCW.png
Any help would be appreciated! This has caused quite a bit of trouble.

Managing database connections in Node.js, best practices?

I'm building an Node application which will query simple and more complex (multiple joins) queries. I'm looking for suggestions on how I should manage the mySQL connections.
I have the following elements:
server.js : Express
router1.js (fictive name) : Express Router middleware
router2.js (fictive name) : Express Router middleware
//this is router1
router.get('/', function (req, res){
connection.connect(function(Err){...});
connection.query('SELECT* FROM table WHERE id = "blah"', function(err,results,fields){
console.log(results);
});
...
connection.end();
})
Should I connect to mysql everytime '/router1/' is requested, like in this example, or it's better to leave one connection open one at start up? As: connection.connect(); outside of: router.get('/',function(req,res){
...
}); ?
I am using mysql2 for this, it is basicly mysql but with promises. If you use mysql you can also do this.
Create a seperate file called connection.js or something.
const mysql = require('mysql2');
const connection = mysql.createPool({
host: "localhost",
user: "",
password: "",
database: ""
// here you can set connection limits and so on
});
module.exports = connection;
Then it is probaly better you create some models and call these from within your controllers, within your router.get('/', (req, res) => {here});
A model would look like this:
const connection = require('../util/connection');
async function getAll() {
const sql = "SELECT * FROM tableName";
const [rows] = await connection.promise().query(sql);
return rows;
}
exports.getAll = getAll;
You can do this with or without promises, it doesn't matter.
Your connection to the pool is automatically released when the query is finished.
Then you should call getAll from your router or app.
I hope this helped, sorry if not.
Connection pooling is how it should be done. Opening a new connection for every request slows down the application and it can sooner or later become a bottleneck, as node does not automatically closes the connections unlike PHP. Thus connection pool ensures that a fixed number of connections are always available and it handles the closing of unnecessary connections as and when required.
This is how I start my express app using Sequelize. For Mongoose, it is more or less simlar except the library API.
const sequelize = new Sequelize('database', 'username', 'password', {
host: 'localhost',
dialect: 'mysql',
pool: {
max: 5,
min: 0,
acquire: 30000,
idle: 10000
}
});
sequelize.authenticate()
.then(
// On successfull connection, open a port
// and listen to requests. This is where the application
// starts listening to requests.
() => {
const server = http.createServer(app);
server.listen(port);
},
)
.catch(err => {
console.error('Unable to connect to the database:', err);
console.error('Cancelling app server launch');
});
The app is started only after a database connection has been established. This ensures that the server won't be active without any database connection. Connection pool will keep the connections open by default, and use a connection out of the pool for all queries.
If you use createPool mysql will manage opening and closing connections and you will have better performance. It doesn't matter if you use mysql or mysql2 or sequlize. use a separate file for createPool and export it. You can use it everywhere. Don't use classes and just do it functionally for better performance in nodejs.
> npm install mysql
mysql is a great module which makes working with MySQL very easy and it provides all the capabilities you might need.
Once you have mysql installed, all you have to do to connect to your database is
var mysql = require('mysql')
var conn = mysql.createConnection({
host: 'localhost',
user: 'username',
password: 'password',
database: 'database'
})
conn.connect(function(err) {
if (err) throw err
console.log('connected')
})
Now you are ready to begin writing and reading from your database.

while using MySql, express, angular, nodejs, will the ports be different for express and node

While looking into express + node + mysql, tutorials suggest to start express server by using node server.js (here server.js contains logic to connect to mysql db), which calls upon app.listen() and angular+node tutorials start node server using npm start.
Are they different and I have to start both?
In case, yes, do I need to use diff ports?
In case, no, how to call upon mysql db? Please give some reference or elaborate.
server.js is as follows:
var express = require("express");
var mysql = require("mysql");
var app = express();
var connection = mysql.createConnection({
host : "localhost",
user : "userid",
password : "password",
database : "sakila"
});
connection.connect(function(error){
if(error) {
console.log("Problem with MySQL"+error);
} else {
console.log("Connected with Database");
}
});
app.use(express.static(__dirname + '/bower_components/angular'));
app.get('/app/#/actors_load',function(req,res){
connection.query("SELECT * from actor",function(err,rows){
if(err) {
console.log("Problem with MySQL"+err);
} else {
res.end(JSON.stringify(rows));
}
});
});
app.listen(8000,function(){
console.log("It's Started on PORT 8000");
});
My phonecatapp has following routers:
phonecatApp.config(['$routeProvider',
function($routeProvider) {
$routeProvider.
when('/phones', {
templateUrl: 'partials/phone-list.html',
controller: 'PhoneListCtrl'
}).
when('/phones/:phoneId', {
templateUrl: 'partials/phone-detail.html',
controller: 'PhoneDetailCtrl'
}).
when('/actors_load', {
templateUrl: 'partials/actors.html',
controller: 'ActorsCtrl'
}).
otherwise({
redirectTo: '/phones'
});
}]);
and controller looks like this:
phonecatControllers.controller('ActorsCtrl',function($scope, $http, $interval){
load_names();
console.log("ActorsCtrl");
/*
$interval(function(){
load_names();
},300);
*/
function load_names(){
$http.get('http://localhost:8000/actors_load').success(function(data){
console.log("kdfhg"+data);
$scope.actors=data;
});
};
});
the partials of html has a link to populate the db data as:
<div>actors</div>
npm install doesn't start a server. It is a command to install packages.
In this particular example the createServer function will accept connection on port 8000. it's taken from node.js docs.
https.createServer(options, function (req, res) {
res.writeHead(200);
res.end("hello world\n");
}).listen(8000);
As soon as the above code is executed the server is ON. express is a framework for node.js. express creates server on the top of node.js so the express configuration (along with port number) will be executed by node.js. Specified port of express server will run an instance of node.js server, that's the end of the story
To connect to mysql you can use one of the mysql packages for node e.g.:
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'localhost',
user : '< MySQL username >',
password : '< MySQL password >',
database : '<your database name>'
});
connection.connect();
In above case you are using localhost as a adress of your database.
You can find plethora of mysql packages on npm site: https://www.npmjs.com/search?q=mysql
You may also use mysql.createClient for costumised connection:
var client = mysql.createClient({
user: '??',
password: '??',
port: 8889
});
Note: remember to require your packages otherwise they just simply won't work.
After doing trial and error, I found that srever.js is on server side, angular part of the project is on client side. from angular part, only way to recieve data is using REST API. This role of providing REST API will be facilitated by server.js and hence shall be run on diff port. It means I had to call npm start as well as node server.js. Then I was facing CORS issue, which I resolved by providing
app.use(function(req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header ("Access-Control-Allow-Credentials", true);
res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
res.header('Access-Control-Allow-Methods', 'POST, GET, PUT, DELETE, OPTIONS');
next();
});
in server.js. NOte that to see the effect of this code, you need to start the two servers. This was really a pain point for me. I spent whole day trying various combinations in various places to resolve CORS issue. It seemed not to be working. For some reasons, I stopped the servers and restarted, it was working. After few trials, I realized that even after removing above code, it was working. So, I stopped servers again and this time it was not working, that is how I realized it.
One more thing that I was mingling the two thinking them as one project having client and server side. Any newbie, please understand that client side accesses server side as REST API, so develop them as separate module/project. Do not develop as single module/project.

Connection to Mysql from NodeJS on Heroku server

ANy idea how can I connect from NodeJs to the Mysql ClearDB on Heroku?
I was able to connect to the ClearDB Mysql runing on Heroku from Navicat, I even created a table called t_users. But I'm having problems connecting from NodeJs from Heroku.
This is my code, it is very simple: everything works find until it tries to connect to MySQL
web.js:
var express = require("express");
var app = express();
app.use(express.logger());
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'us-cdbr-east-04.cleardb.com',
user : '',
password : '',
database : ''
});
connection.connect();
app.get('/', function(request, response) {
response.send('Hello World!!!! HOLA MUNDOOOOO!!!');
connection.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
if (err) throw err;
response.send('The solution is: ', rows[0].solution);
});
});
var port = process.env.PORT || 5000;
app.listen(port, function() {
console.log("Listening on " + port);
});
This is what I got when I run on the command line: Heroku config
C:\wamp\www\Nodejs_MySql_Heroku>heroku config
=== frozen-wave-8356 Config Vars
CLEARDB_DATABASE_URL: mysql://b32fa719432e40:87de815a#us-cdbr-east-04.cleardb.com/heroku_28437b49d76cc53?reconnect=true
PATH: bin:node_modules/.bin:/usr/local/bin:/usr/bin:/bin
This is the LOG:
http://d.pr/i/cExL
ANy idea how can I connect from NodeJs to the Mysql ClearDB on Heroku?
Thanks
Try this. Hope this will help you
mysql://b32fa719432e40:87de815a#us-cdbr-east-04.cleardb.com/heroku_28437b49d76cc53?reconnect=true
var connection = mysql.createConnection({
host : 'us-cdbr-east-04.cleardb.com',
user : 'b32fa719432e40',
password : '87de815a',
database : 'heroku_28437b49d76cc53'
});
Use this details and connect it in mySQL work bench, and import your localhost db
The base code was ok, I missed some NodeJS code.
I did a video explaining how to connect to MySqlusing NodeJS on a Heroku server, take a look:
http://www.youtube.com/watch?v=2OGHdii_42s
This is the code in case you want to see:
https://github.com/mescalito/MySql-NodeJS-Heroku
createConnections accepts config as well as connectionString.
export function createConnection(connectionUri: string | ConnectionConfig): Connection;
So below solution would work.
var connection = mysql.createConnection('mysql://b32fa719432e40:87de815a#us-cdbr-east-04.cleardb.com/heroku_28437b49d76cc53?reconnect=true);
or you can set the connection url in environment variable DATABASE_URL
var connection = mysql.createConnection(process.env.DATABASE_URL);
One should need to use pool connection for database connection to handle better mysql conncurrent request as follows
var pool = mysql.createPool({
connectionLimit : 100,
host : 'us-cdbr-iron-east-05.cleardb.net',
user : 'b5837b0f1d3d06',
password : '9d9ae3d5',
database : 'heroku_db89e2842543609',
debug : 'false'
});
It just because pool maintain the connection.release() on its own , so you do not have to bother where you should need to release the connection.
On the other hand you should need to provide user, password and database name as i mentioned in my code.
When u get provisioned from heroku then you get a cleardb database name.
on clicking clear db database button you will find username and password.
and to get database url you have to run the following commands in terminal as follows;
heroku login
heroku app -all (it shows the app list name )
heroku config --app appname (it will provide the database url).
Rest you would need to worry, just add all dependency into your package.json before pushing to heroku master.
After then you will have no problem on deploying nodejs application to heroku server.
Looking at the log timestamps, it seems like your connections are timing out. Either create a wrapper for 'getConnection' that checks the connection health and re-establishes if necessary, or try to use the mysql Connection Pool feature, which can do that for you.