ClientEventsWebSocket.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Waher.Content;
using Waher.Events;
using Waher.Networking.HTTP;
using Waher.Networking.HTTP.WebSockets;
using Waher.Security;
 
namespace Waher.IoTGateway
{
    public class ClientEventsWebSocket : WebSocketListener
    {
        private static readonly string serverId = Hashes.BinaryToString(Gateway.NextBytes(32));
 
        public ClientEventsWebSocket()
            : base("/ClientEventsWS", true, 10 * 1024 * 1024, 10 * 1024 * 1024, "ls")
        {
            this.Accept += this.ClientEventsWebSocket_Accept;
            this.Connected += this.ClientEventsWebSocket_Connected;
        }
 
        public override Task GET(HttpRequest Request, HttpResponse Response)
        {
            SetTransparentCorsHeaders(this, Request, Response);
            return base.GET(Request, Response);
        }
 
        private Task ClientEventsWebSocket_Connected(object Sender, WebSocketEventArgs e)
        {
            e.Socket.Closed += this.Socket_Closed;
            e.Socket.Disposed += this.Socket_Disposed;
            e.Socket.TextReceived += this.Socket_TextReceived;
        
            return Task.CompletedTask;
        }
 
        private async Task Socket_TextReceived(object Sender, WebSocketTextEventArgs e)
        {
            if (JSON.Parse(e.Payload) is Dictionary<string, object> Obj &&
                Obj.TryGetValue("cmd", out object Value) && Value is string Command)
            {
                switch (Command)
                {
                    case "Register":
                        if (Obj.TryGetValue("tabId", out object O1) && O1 is string TabID &&
                            Obj.TryGetValue("location", out object O2) && O2 is string Location)
                        {
                            e.Socket.Tag = new Info()
                            {
                                Location = Location,
                                TabID = TabID
                            };
 
                            try
                            {
                                await ClientEvents.RegisterWebSocket(e.Socket, Location, TabID);
                            }
                            catch (Exception ex)
                            {
                                Log.Exception(ex);
                            }
 
                            await ClientEvents.PushEvent(new string[] { TabID }, "CheckServerInstance", serverId, false);
                        }
                        break;
 
                    case "Unregister":
                        await this.Close(e.Socket);
                        break;
 
                    case "Ping":
                        if (e.Socket.Tag is Info Info)
                            ClientEvents.Ping(Info.TabID);
                        break;
                }
            }
        }
 
        private class Info
        {
            public string Location;
            public string TabID;
        }
 
        private async Task Socket_Disposed(object Sender, EventArgs e)
        {
            if (Sender is WebSocket WebSocket)
                await this.Close(WebSocket);
        }
 
        private Task Socket_Closed(object Sender, WebSocketClosedEventArgs e)
        {
            return this.Close(e.Socket);
        }
 
        private async Task Close(WebSocket Socket)
        {
            if (Socket.Tag is Info Info)
            {
                await ClientEvents.UnregisterWebSocket(Socket, Info.Location, Info.TabID);
                Socket.Tag = null;
            }
        }
 
        private Task ClientEventsWebSocket_Accept(object Sender, WebSocketEventArgs e)
        {
            // Cross-domain use allowed.
            //
            //HttpFieldCookie Cookie;
            //
            //if ((Cookie = e.Socket.HttpRequest.Header.Cookie) is null ||
            //  string.IsNullOrEmpty(Cookie[HttpResource.HttpSessionID]))
            //{
            //  throw new ForbiddenException("HTTP Session required.");
            //}
 
            return Task.CompletedTask;
        }
 
        public override bool HandlesSubPaths
        {
            get
            {
                return false;
            }
        }
    }
}