WebSocket router class

ws-router.ts

import * as crypto from 'node:crypto'
import { IncomingMessage } from 'node:http'
import { Duplex } from "node:stream";
import { AppConfig } from '../app-config.js'
import { WebSocketOpcode, WebSocketFrame } from './ws-frame.js';
import { WebSocketMessage } from '../../common/ws-message.js';
import { WebSocketAPI } from './ws-api.js';

export class WebSocketRouter {

    private ws_clients: { [id: string]: Duplex } = {}

    constructor() { }

    public on_upgrade(req: IncomingMessage, socket: Duplex, head: Buffer) {

        try {
            if (req.headers['upgrade'] != 'websocket') return

            let key: string = req.headers['sec-websocket-key']
            let hash: crypto.Hash = crypto.createHash('sha1')
            let accept: string = key + AppConfig.ws_rfc_guid
            let accept_hash: string = hash.update(accept, 'binary').digest('base64')

            let headers = [
                'HTTP/1.1 101 Switching Protocols',
                'Upgrade: websocket',
                'Connection: Upgrade',
                'Sec-WebSocket-Accept: ' + accept_hash
            ]

            this.ws_clients[key] = socket
            socket.on('data', this.on_data.bind(this, key))
            socket.write(headers.concat('\r\n').join('\r\n'))
        }
        catch(e) { console.log(e) }        
    }

    private on_data(id: string, data: Buffer) {

        try {
            let final: boolean = Boolean(data[0] >>> 7)
            let opcode: number = (data[0] & 0b00001111)

            switch (opcode) {

                case WebSocketOpcode.TEXT:
                    return this.parse_message(id, WebSocketFrame.parse(data))

                default:
                case WebSocketOpcode.CLOSE:
                    this.ws_clients[id].destroy()
                    return delete this.ws_clients[id]                
            }
        }
        catch (e) { console.log(e) }
    }

    private parse_message(id: string, message: Buffer) {

        try {
            let msg = WebSocketMessage.parse(message.toString())
            WebSocketAPI.handle(msg).then(((response: WebSocketMessage) => this.send_message(id, response)).bind(this))
        }
        catch(e) { console.log(e) }
    }

    public send_message(id: string, data: object) {

        try { this.ws_clients[id].write(WebSocketFrame.build(data)) }
        catch(e) { console.log(e) }
    }
}