Websocket sample implementation.

# all generated directories

wwwroot/

!wwwroot/ws.html

Attributes/

Authentication/

Converters/

//

// ARF - Augmented Reality Framework (ETSI ISG ARF)

//

// Copyright 2024 ETSI

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

//

// Last change: June 2024

//

using System;

using System.Text;

using System.Collections.Generic;

using System.Linq;

using System.Threading;

using System.Threading.Tasks;

using System.Net.WebSockets;

using Microsoft.AspNetCore.Authorization;

using Microsoft.AspNetCore.Mvc;

using Microsoft.AspNetCore.Http;

using Swashbuckle.AspNetCore.Annotations;

using Swashbuckle.AspNetCore.SwaggerGen;

#pragma warning disable CS1591 // Fehlendes XML-Kommentar fr ffentlich sichtbaren Typ oder Element

namespace ETSI.ARF.OpenAPI.WorldStorage.Services

{

    //

    // ETSI-ARF World Analysis WebSocket implementation

    // see also: https://learn.microsoft.com/de-de/aspnet/core/fundamentals/websockets?view=aspnetcore-5.0

    //

    public class WebSocketController : ControllerBase

    {

        [HttpGet("/ws")]

        public async Task Get()

        {

            if (HttpContext.WebSockets.IsWebSocketRequest)

            {

                using var webSocket = await HttpContext.WebSockets.AcceptWebSocketAsync();

                if (webSocket.State == WebSocketState.Open)

                {

                    // Response an OK message

                    await SendText(webSocket, "Hello, here is the ARF World Analysis services!");

                }

                await Echo(HttpContext, webSocket);

            }

            else

            {

                await HttpContext.Response.WriteAsync("ETSI-ARF World Analysis: Not a valid WebSocket request.");

                HttpContext.Response.StatusCode = StatusCodes.Status400BadRequest;

            }

        }

        //

        // Send a line of text

        //

        private async Task SendText(WebSocket webSocket, string text)

        {

            // Response an OK message

            var message = text;

            var bytes = Encoding.UTF8.GetBytes(message);

            var arraySegment = new ArraySegment<byte>(bytes, 0, bytes.Length);

            await webSocket.SendAsync(arraySegment, WebSocketMessageType.Text, true, CancellationToken.None);

        }

        //

        // Send the time all seconds

        //

        private async Task SendTime(WebSocket webSocket)

        {

            while (true)

            {

                var message = "Hello, my time is: " + DateTime.Now.ToLocalTime();

                var bytes = Encoding.UTF8.GetBytes(message);

                var arraySegment = new ArraySegment<byte>(bytes, 0, bytes.Length);

                if (webSocket.State == WebSocketState.Open)

                {

                    await webSocket.SendAsync(arraySegment, WebSocketMessageType.Text, true, CancellationToken.None);

                }

                else if (webSocket.State == WebSocketState.Closed || webSocket.State == WebSocketState.Aborted)

                {

                    break;

                }

                Thread.Sleep(1000);

            }

        }

        //

        // Echo incoming messages

        //

        private async Task Echo(HttpContext context, WebSocket webSocket)

        {

            var buffer = new byte[1024 * 4];

            // get the first data block

            WebSocketReceiveResult result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);

            while (!result.CloseStatus.HasValue)

            {

                // test

                await SendText(webSocket, "Thanks, I got this message:");

                // echo the message back to the client

                await webSocket.SendAsync(new ArraySegment<byte>(buffer, 0, result.Count), result.MessageType, result.EndOfMessage, CancellationToken.None);

                // get the next block

                result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);

            }

            await webSocket.CloseAsync(result.CloseStatus.Value, result.CloseStatusDescription, CancellationToken.None);

        }

    }

}

#pragma warning restore CS1591 // Fehlendes XML-Kommentar fr ffentlich sichtbaren Typ oder Element

                app.UseHsts();

            }

            // ETSI-ARF Websocket implementation

            var webSocketOptions = new WebSocketOptions()

            {

                KeepAliveInterval = TimeSpan.FromSeconds(120),

            };

            //webSocketOptions.AllowedOrigins.Add("https://etsi.hhi.fraunhofer.de");

            //webSocketOptions.AllowedOrigins.Add("https://www.client.com");

            app.UseWebSockets();

            app.UseHttpsRedirection();

            app.UseDefaultFiles();

            app.UseStaticFiles();