Express.js
01. Getting start
## ------------------| One Rule to Rule Them All
npx express-generator -f --git
## ------------------| Create package.json
npm init -f
## ------------------| Install dependencies
### Install app directory and save it in the dependencies list
npm install express cors nodemon dotenv
### Install temporarily and not add it to the dependencies list
npm install express cors nodemon dotenv --no-save
## ------------------| Changes on package.json
"scripts": {
"start": "nodemon src/app.js"
}
## ------------------| Create .gitignore file
/node_modules
.env
/.pnp
.pnp.js
/coverage
/build
.DS_Store
.env.local
.env.development.local
.env.test.local
.env.production.local
npm-debug.log*
yarn-debug.log*
yarn-error.log* app.js
const express = require('express')
const cors = require('cors')
const app = express()
const port = 3000
// Loads environment variables from a .env file [to use process.env.NAME]
require('dotenv').config()
// Middlewares [app.use(<a function>);]
app.use(cors());
// Register Routes
app.get('/api/v1/test', (req, res) => {
res.send('Hello h4rithd.com')
})
app.listen(port, () => {
console.log(`App listening on port ${port}`)
})02. Register Routes
## ------------------| For GET Request
### [text/html]
app.get('/api/v1/test', (req, res) => {
res.send('Hello h4rithd.com')
})
### [application/json]
app.get('/api/v1/json', (req, res) => {
res.json({
message: "Hello h4rithd.com"
})
})
## ------------------| For POST Request
app.post('/api/v1/test', (req, res) => {
res.send('Hello h4rithd.com')
})
## ------------------| For PUT Request
app.put('/api/v1/test', (req, res) => {
res.send('Hello h4rithd.com')
})
## ------------------| For POST Request
app.post('/api/v1/test', (req, res) => {
res.send('Hello h4rithd.com')
})03. Database Management
03.1 MongoDB
Getting started
## ------------------| Install dependencies
npm init -y
npm install mongoose express nodemonConnect to database
const mongoose = require('mongoose');
mongoose.connect('mongodb//<username>:<password>@localhost/my_database').then(() => {
app.listen(port, () => {
console.log(`App listening on port ${port}`)
})
});Insert data to database [Basic]
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const Item = new Schema({
item: String,
});
mongoose.model("Item", Item);
app.post('/items', async (req, res) => {
const item = req.body;
const ItemModel = mongoose.model("Item");
const myItem = new ItemModel(item);
const createdItem = await myItem.save(); // Save data to database
console.log(createdItem);
res.send('Hello h4rithd.com');
})Insert data to database [Structured]
## ------------------| src/app.js
const mongoose = require('mongoose');
const express = require('express')
const cors = require('cors')
const app = express()
const port = 3000
require('./models/item');
app.use(cors());
app.use(express.json())
app.post('/items', require("./route/insertItem"));
mongoose.connect('mongodb//<username>:<password>@localhost/my_database').then(() => {
app.listen(port, () => {
console.log(`App listening on port ${port}`)
})
});
## ------------------| ./src/models/item.js
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const Item = new Schema({
item: {
type: String,
require: true
},
});
mongoose.model("Item", Item);
## ------------------| ./route/insertItem.js
const mongoose = require('mongoose');
module.exports = async (req, res) => {
const item = req.body;
const ItemModel = mongoose.model("Item");
const myItem = new ItemModel(item);
const createdItem = await myItem.save(); // Save data to database
console.log(createdItem);
res.send('Hello h4rithd.com');
};03.2 SQLiteDB
Getting started
npm init -y
npm install express sqlite3 body-parser bcryptjs jsonwebtoken nodemon
## ------------------| Changes on package.json
"scripts": {
"start": "nodemon src/app.js"
}Create app.js
const express = require('express');
const sqlite3 = require('sqlite3').verbose();
const bodyParser = require('body-parser');
const bcrypt = require('bcryptjs');
const jwt = require('jsonwebtoken');
const app = express();
app.use(bodyParser.json());
const db = new sqlite3.Database('./database.db');
// Create tables if they don't exist
db.serialize(() => {
db.run(`CREATE TABLE IF NOT EXISTS users (
id INTEGER PRIMARY KEY AUTOINCREMENT,
username TEXT UNIQUE,
email TEXT,
password TEXT,
name TEXT,
isAdmin INTEGER
)`);
db.run(`CREATE TABLE IF NOT EXISTS messages (
id INTEGER PRIMARY KEY AUTOINCREMENT,
username TEXT,
message TEXT,
date TEXT
)`);
});
// JWT Secret
const JWT_SECRET = "your_secret_key";
// Register route
app.post('/api/v1/register', (req, res) => {
const { username, email, password, name, isAdmin } = req.body;
// Hash password
const hashedPassword = bcrypt.hashSync(password, 10);
db.run(`INSERT INTO users (username, email, password, name, isAdmin) VALUES (?, ?, ?, ?, ?)`,
[username, email, hashedPassword, name, isAdmin ? 1 : 0],
function (err) {
if (err) {
return res.status(400).json({ error: err.message });
}
res.json({ message: "User registered successfully" });
}
);
});
// Login route
app.post('/api/v1/login', (req, res) => {
const { username, password } = req.body;
db.get(`SELECT * FROM users WHERE username = ?`, [username], (err, user) => {
if (err) return res.status(500).json({ error: err.message });
if (!user) return res.status(400).json({ error: "User not found" });
// Compare password
if (!bcrypt.compareSync(password, user.password)) {
return res.status(400).json({ error: "Invalid password" });
}
// Generate JWT token
const token = jwt.sign({ id: user.id, username: user.username, isAdmin: user.isAdmin }, JWT_SECRET);
res.json({ token });
});
});
// Middleware to authenticate JWT token
const authenticateJWT = (req, res, next) => {
const token = req.headers.authorization;
if (!token) return res.status(403).json({ error: "Token missing" });
jwt.verify(token, JWT_SECRET, (err, user) => {
if (err) return res.status(403).json({ error: "Invalid token" });
req.user = user;
next();
});
};
// Send message route
app.post('/api/v1/sendMessage', authenticateJWT, (req, res) => {
const { message } = req.body;
const username = req.user.username;
const date = new Date().toISOString();
db.run(`INSERT INTO messages (username, message, date) VALUES (?, ?, ?)`,
[username, message, date],
function (err) {
if (err) return res.status(500).json({ error: err.message });
res.json({ message: "Message sent successfully" });
}
);
});
// Update user route (Admin only)
app.put('/api/v1/updateUser', authenticateJWT, (req, res) => {
if (!req.user.isAdmin) return res.status(403).json({ error: "Only admin can update user" });
const { id, username, email, name, isAdmin } = req.body;
db.run(`UPDATE users SET username = ?, email = ?, name = ?, isAdmin = ? WHERE id = ?`,
[username, email, name, isAdmin ? 1 : 0, id],
function (err) {
if (err) return res.status(500).json({ error: err.message });
if (this.changes === 0) return res.status(400).json({ error: "User not found" });
res.json({ message: "User updated successfully" });
}
);
});
// Start server
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
console.log(`Server running on port ${PORT}`);
});
04. Deploying
Process Manager (PM2)
npm install -g pm2
pm2 start app.js --name "myapp" --watch
pm2 save ## save the configuration for restart persistence
pm2 startup ## set up PM2 to start on boot
pm2 list ## list all
pm2 logs "myapp" ## display logs
pm2 restart ## restartFor DEV env
## ------------------| Specify which files or directories to watch (pm2.config.js)
module.exports = {
apps: [
{
name: 'app',
script: './app.js',
watch: true,
ignore_watch: ['node_modules', 'logs']
}
]
};
## pm2 start pm2.config.jsFor PROD env
## ------------------| Set environment variables (pm2.config.js)
module.exports = {
apps: [
{
name: 'app',
script: './app.js',
env: {
NODE_ENV: 'development',
PORT: 3000
},
env_production: {
NODE_ENV: 'production',
PORT: 80
}
}
]
};
## pm2 start pm2.config.js --env production
## pm2 startupLast updated
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