brainlet/api/v1/gateway/index.js

const User = require('../../../models/User');
const secret = require('../../../secret');
const config = require('../../../config');

const jwt = require('jsonwebtoken');
const siolib = require('socket.io')

class GatewayServer {
    constructor(httpServer) {
        this._io = siolib(httpServer);
        this._gateway = this._io.of('/gateway');
        this.eventSetup();
    }
}

GatewayServer.prototype.authDisconnect = function(socket, callback) {
    console.log('[E] [gateway] [handshake] User disconnected due to failed authentication');
    socket.isConnected = false;
    socket.disconnect();
    socket.disconnect(true);
    callback(new Error('ERR_GATEWAY_AUTH_FAIL'));
};

GatewayServer.prototype.eventSetup = function() {
    this._gateway.use((socket, callback) => {
        console.log('[*] [gateway] [handshake] User authentication attempt');
        socket.isConnected = false;

        setTimeout(() => {
            if (socket.isConnected) return;
            console.log('[*] [gateway] [handshake] User still not connected after timeout, removing...');
            socket.disconnect();
            socket.disconnect(true);
        }, config.gatewayStillNotConnectedTimeoutMS);

        // TODO: Maybe passing the token in the query is not the best idea?
        const token = socket.handshake.query.token;

        if (!token) return this.authDisconnect(socket, callback);

        jwt.verify(token, secret.jwtPrivateKey, {}, async (err, data) => {
            if (err) return this.authDisconnect(socket, callback);
            if (!data) return this.authDisconnect(socket, callback);
            if (!data.username) return this.authDisconnect(socket, callback);

            const user = await User.findByUsername(data.username);

            if (!user) return this.authDisconnect(socket, callback);

            let permissionLevel = config.roleMap[user.role];
            if (!permissionLevel) {
                permissionLevel = 0;
            }

            if (permissionLevel < config.roleMap.USER) return this.authDisconnect(socket, callback);

            socket.username = data.username;
            console.log(`[*] [gateway] [handshake] User ${data.username} has successfully authenticated`);
            return callback();
        });
    });

    this._gateway.on('connection', (socket) => {
        console.log(`[*] [gateway] [handshake] User ${socket.username} connected, sending hello and waiting for yoo...`);
        socket.emit('hello');
        socket.once('yoo', () => {
            console.log(`[*] [gateway] [handshake] Got yoo from ${socket.username}, connection is finally completed!`);
            socket.isConnected = true;

            socket.on('message', ({ categoryId, content }) => {
                // TODO: URGENT: Check if the category exists and if the user has access to it (access coming soon)
                socket.to(categoryId).emit('message', {
                    username: socket.username,
                    categoryId: categoryId,
                    content: content
                });
            });

            socket.on('subscribe', (categories) => {
                for (let v of categories) {
                    // TODO: URGENT: Check if the category exists and if the user has access to it (access coming soon)
                    socket.join(v);
                }    
            });
        });
    });
};

module.exports = GatewayServer;