ALTV WebsocketSharp with LetsEncrypt SSL (https://github.com/sta/websocket-sharp)

1-AltVWsSharp.cs

using AltV.Net.Data;
using System;
using System.Collections.Generic;
using System.Net.Security;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;
using System.Threading;
using System.Threading.Tasks;
using WebSocketSharp;
using WebSocketSharp.Server;

public class WebSocketManager
{
    private static WebSocketServer _server;

    public void Run( )
    {
        // YourPort = any port you want to run the WS server on
        _server = new WebSocketServer( YourPort, true );
        
        // Example for LetsEncrypt SSL certificates on ubuntu
        // YourSslCertificate => /etc/letsencrypt/live/yourwebsite.com/cert.pem
        // YourSslKey => /etc/letsencrypt/live/yourwebsite.com/privkey.pem

        X509Certificate2 cert = X509Certificate2.CreateFromPemFile( YourSslCertificate, YourSslKey );

        _server.SslConfiguration.ServerCertificate = cert;
        _server.SslConfiguration.ClientCertificateRequired = false; // Not entirely sure if this is required
        _server.SslConfiguration.CheckCertificateRevocation = false; // Not entirely sure if this is required
        _server.SslConfiguration.EnabledSslProtocols = SslProtocols.Tls12; // This is definitely required

        // Not entirely sure if this is required.
        _server.SslConfiguration.ClientCertificateValidationCallback = (object sender, X509Certificate? certificate, X509Chain? chain, SslPolicyErrors sslPolicyErrors) =>
        {
            return true;
        };
        
        // Change this to the URL at which you want to host the websocket server, eg use "/ws" for example.com/ws
        _server.AddWebSocketService<WebSocketService>( "/" );
        _server.Start( );
        
        Console.WriteLine( "[MANAGER] WebSocket Server is listening: " + _server.IsListening );
    }
}

public class WebSocketService : WebSocketBehavior
{
    protected override void OnMessage( MessageEventArgs e )
    {
        Console.WriteLine( $"WS Message: { e.Data }" );
    }

    protected override void OnOpen( )
    {
        Console.WriteLine( $"Client connected!" );
    }

    protected override void OnClose( CloseEventArgs e )
    {
        Console.WriteLine( $"Client disconnected!" );
    }

    protected override void OnError( ErrorEventArgs e )
    {
        Console.WriteLine( e.Message );
    }
}



// In any other file(eg via DI, or server start method)
WebSocketManager ws = new WebSocketManager( ).Run( );

// For client-side use ALTV's built-in WebSocketClient, example below.

2-AltVWsClient.ts

import * as alt from 'alt-client';

// Specify URL and port here
const wsClient = new alt.WebSocketClient( "wss://YOUR_WS_URL:YOUR_WS_PORT" );
wsClient.autoReconnect = true; // auto reconnect if it disconnects for some reason

wsClient.on( "open", ( ) => {
    alt.log( "[WEBSOCKET] Connected!" );
} );

wsClient.on( "close", ( code, reason ) => {
    alt.log( `[WEBSOCKET] Disconnected: ${ code }, ${ reason }` );
} );

wsClient.on( "error", ( error ) => {
    alt.log( `[WEBSOCKET] Disconnected: ${ error }` );
} );

wsClient.on( "message", ( message ) => {
    alt.log( `[WEBSOCKET] message: ${ message }` );
} );

wsClient.start( );