Nodejs Socket.io MySql – Role Based Access Control (RBAC)

Here is an example of how you could implement role-based access control (RBAC) using Node.js, socket.io, and MySQL:

const express = require('express');
const app = express();
const server = require('http').Server(app);
const io = require('socket.io')(server);
const mysql = require('mysql2');

const connection = mysql.createConnection({
  host: 'localhost',
  user: 'your_username',
  password: 'your_password',
  database: 'your_database'
});

io.on('connection', (socket) => {
  socket.on('authenticate', (data) => {
    const { username, password } = data;
    // Check if the username and password match a user in the database
    const query = `SELECT role FROM users WHERE username = ? AND password = ?`;
    connection.query(query, [username, password], (error, results) => {
      if (error) {
        console.error(error);
      } else {
        const role = results[0].role;
        // Store the user's role in the socket object for later use
        socket.role = role;
        // Emit an event to the client to let them know they are authenticated
        socket.emit('authenticated');
      }
    });
  });

  socket.on('restricted_event', () => {
    // Only allow users with the "admin" role to access this event
    if (socket.role === 'admin') {
      // Do something only an admin is allowed to do
      console.log('Admin action completed');
    } else {
      // Send an error message to the client if the user does not have the necessary role
      socket.emit('access_denied', 'You do not have permission to perform this action');
    }
  });
});

server.listen(3000, () => {
  console.log('Listening on port 3000');
});

This code sets up an HTTP server using express and socket.io, and connects to a MySQL database using the mysql2 library. When a client connects to the server, they can send an authenticate event with their username and password. The server will check the database to see if there is a matching user, and if there is, it will store the user’s role in the socket object for later use.

The server also sets up an event listener for a restricted_event, which is only accessible to users with the admin role. If a user with a different role tries to access this event, they will receive an access_denied event with an error message.