How Proxy Server Works With Node Js practical

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     // Require the 'net' module for TCP networking

 const net = require('net');
 
    // Define the target host and port
    const targetHost = 'localhost'; // Specify the hostname of the target server
    const targetPort = 80; // Specify the port of the target server

    // Create a TCP server
    const server = net.createServer((clientSocket) => {
        // Establish a connection to the target host
        const targetSocket = net.createConnection({ host: targetHost, port: targetPort }, () => {
            // When data is received from the target server, write it back to the client
            targetSocket.on("data", (data) => {
                clientSocket.write(data);
            });

            // When data is received from the client, write it to the target server
            clientSocket.on("data", (data) => {
                targetSocket.write(data);
            });
        });

        // Handle errors when connecting to the target server
        targetSocket.on('error', (err) => {
            console.error('Error connecting to target:', err);
            clientSocket.end();
        });

        // Handle errors related to the client socket
        clientSocket.on('error', (err) => {
            console.error('Client socket error:', err);
            targetSocket.end();
        });
    });

    // Start listening for incoming connections on the specified port
    const proxyPort = 3000; // Specify the port for the proxy server
    server.listen(proxyPort, () => {
        console.log(`Reverse proxy server is listening on port ${proxyPort}`);
    });



Another METHOD using pipe


const net = require('net');

// Define the target host and port
const targetHost = 'localhost';
const targetPort = 80;

// Create a TCP server
const server = net.createServer((clientSocket) => {
    // Establish a connection to the target host
    const targetSocket = net.createConnection({ host: targetHost, port: targetPort }, () => {
        // Pipe data from the client to the target
        clientSocket.pipe(targetSocket);
       
        // Pipe data from the target to the client
        targetSocket.pipe(clientSocket);
    });

    // Handle errors
    targetSocket.on('error', (err) => {
        console.error('Error connecting to target:', err);
        clientSocket.end();
    });

    clientSocket.on('error', (err) => {
        console.error('Client socket error:', err);
        targetSocket.end();
    });
});

// Start listening for incoming connections
const proxyPort = 3000;
server.listen(proxyPort, () => {
    console.log(`Reverse proxy server is listening on port ${proxyPort}`);
});


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