HTTP & HTTPS servers in nodejs

1. The Core Architecture: Request-Response Cycle A web server is a process that listens for incoming network requests and returns a response. In Node.js, this is handled by the Event Loop , allowing the server to handle multiple connections efficiently. Request ( req ): An object containing data about the incoming call (URL, headers, body). Response ( res ): An object used to send data back to the client (Status codes, HTML, JSON). 2. Protocol Comparison: HTTP vs. HTTPS HyperText Transfer Protocol (HTTP) Port: Default is 80. Security: Data is sent in "Plain Text." If a hacker intercepts the packet, they can read everything (passwords, credit card info). Use Case: Local development and internal testing. HTTP Secure (HTTPS) Port: Default is 443. Mechanism: Uses TLS (Transport Layer Security) to encrypt data. Handshake: Before data is sent, the client and server perform a "handshake" to agree on encryption keys. 3. How HTTPS Encryption Works HTTPS relies on Public Key Infrastructure (PKI) . The server provides a Public Key (Certificate) to the client, while keeping a Private Key secret. Client Hello: Client requests a secure session. Server Certificate: Server sends its certificate (public key). Authentication: Client verifies the certificate with a Certificate Authority (CA). Key Exchange: A unique symmetric session key is created for that specific session. 4. Implementation Guide Building the HTTP Server The http module is built-in. It is used to create a listener on a specific port. const http = require('http'); const server = http.createServer((req, res) => {     // Setting the HTTP Header     res.writeHead(200, {'Content-Type': 'application/json'});          // Sending the body     res.end(JSON.stringify({ message: "Success" })); }); server.listen(8080); Transitioning to HTTPS To move to HTTPS, the server requires two files: Private Key ( .key ): Kept on the server; never shared. Certificate ( .cert or .pem ): Shared with the browser to prove identity. const https = require('https'); const fs = require('fs'); const options = {     key: fs.readFileSync('server.key'),     cert: fs.readFileSync('server.cert') }; https.createServer(options, (req, res) => {     res.end('Secure Connection Established'); }).listen(443); .