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In this tutorial, we'll walk through adding session management to a Node.js Express application and connecting it to both MongoDB and MySQL databases.
Before getting started, make sure you have the following installed:
- Node.js and npm
- MongoDB (if using MongoDB)
- MySQL (if using MySQL)
First, let's set up a basic Express application:
mkdir express-session-tutorial
cd express-session-tutorial
npm init -y
npm install express express-session
Create a server.js file with the following content:Copy code
const express = require('express');
const session = require('express-session');
const app = express();
const PORT = process.env.PORT || 3000;
app.use(session({
secret: 'your-secret-key',
resave: false,
saveUninitialized: true
}));
app.get('/', (req, res) => {
req.session.views = (req.session.views || 0) + 1;
res.send(`You have visited this page ${req.session.views} times.`);
});
app.listen(PORT, () => {
console.log(`Server is running on port ${PORT}`);
});
Now, run your server:
bash
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node server.js
Visit http://localhost:3000 in your browser. You should see the visit count increment each time you refresh.Step 2: Connect to MongoDB To connect to MongoDB, you'll need to install mongodb package:
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npm install mongodb
Now, modify server.js to connect to MongoDB:
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const express = require('express');
const session = require('express-session');
const { MongoClient } = require('mongodb');
const app = express();
const PORT = process.env.PORT || 3000;
const client = new MongoClient('mongodb://localhost:27017', { useUnifiedTopology: true });
app.use(session({
secret: 'your-secret-key',
resave: false,
saveUninitialized: true
}));
app.get('/', async (req, res) => {
try {
const db = client.db('test');
const counter = db.collection('counter');
const doc = await counter.findOneAndUpdate({}, { $inc: { count: 1 } }, { upsert: true });
res.send(`You have visited this page ${doc.value.count} times.`);
} catch (error) {
console.error(error);
res.status(500).send('Server Error');
}
});
client.connect().then(() => {
app.listen(PORT, () => {
console.log(`Server is running on port ${PORT}`);
});
});Step 3: Connect to MySQL To connect to MySQL, you'll need to install mysql package:
npm install mysql
Now, modify server.js to connect to MySQL:javascript Copy code
const express = require('express');
const session = require('express-session');
const mysql = require('mysql');
const app = express();
const PORT = process.env.PORT || 3000;
const connection = mysql.createConnection({
host: 'localhost',
user: 'your-username',
password: 'your-password',
database: 'your-database'
});
app.use(session({
secret: 'your-secret-key',
resave: false,
saveUninitialized: true
}));
app.get('/', (req, res) => {
connection.query('SELECT COUNT(*) AS count FROM visits', (error, results) => {
if (error) {
console.error(error);
return res.status(500).send('Server Error');
}
const count = results[0].count;
res.send(`You have visited this page ${count} times.`);
});
});
connection.connect((error) => {
if (error) {
console.error('Error connecting to MySQL:', error);
return;
}
console.log('Connected to MySQL');
app.listen(PORT, () => {
console.log(`Server is running on port ${PORT}`);
});
});npm install dotenvrequire('dotenv').config();
const dbHost = process.env.DB_HOST;
const dbUser = process.env.DB_USER;
const dbPassword = process.env.DB_PASSWORD;
const dbDatabase = process.env.DB_DATABASE;DB_HOST=localhost
DB_USER=myuser
DB_PASSWORD=mypassword
DB_DATABASE=mydatabase
# Ignore node_modules directory
node_modules/
# Ignore .env file
.env
# Ignore log files
*.logdocker
docker run --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:tag
docker run --name some-mongo -d mongo:tag
docker exec -it some-mongo bash
docker logs some-mongo
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