.NET Core 基于Websocket的在线聊天室实现

//客户端请求
GET / HTTP/1.1
Upgrade: websocket
Connection: Upgrade
Host: example.com
Origin: http://example.com
Sec-WebSocket-Key: sN9cRrP/n9NdMgdcy2VJFQ==
Sec-WebSocket-Version: 13

//服务端响应
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: fFBooB7FAkLlXgRSz0BT3v4hq5s=
Sec-WebSocket-Location: ws://example.com/

 public async Task Invoke(HttpContext context)
 {
  if (context.Request.Path == "/ws")
  {
  if (context.WebSockets.IsWebSocketRequest)
  {
   WebSocket webSocket = await context.WebSockets.AcceptWebSocketAsync();
   string clientId = Guid.NewGuid().ToString(); ;
   var wsClient = new WebsocketClient
   {
   Id = clientId,
   WebSocket = webSocket
   };
   try
   {
   await Handle(wsClient);
   }
   catch (Exception ex)
   {
   _logger.LogError(ex, "Echo websocket client {0} err .", clientId);
   await context.Response.WriteAsync("closed");
   }
  }
  else
  {
   context.Response.StatusCode = 404;
  }
  }
  else
  {
  await _next(context);
  }
 }

 private async Task Handle(WebsocketClient webSocket)
 {
  WebsocketClientCollection.Add(webSocket);
  _logger.LogInformation($"Websocket client added.");
  
  WebSocketReceiveResult result = null;
  do
  {
  var buffer = new byte[1024 * 1];
  result = await webSocket.WebSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
  if (result.MessageType == WebSocketMessageType.Text && !result.CloseStatus.HasValue)
  {
   var msgString = Encoding.UTF8.GetString(buffer);
   _logger.LogInformation($"Websocket client ReceiveAsync message {msgString}.");
   var message = JsonConvert.DeserializeObject<Message>(msgString);
   message.SendClientId = webSocket.Id;
   MessageRoute(message);
  }
  }
  while (!result.CloseStatus.HasValue);
  WebsocketClientCollection.Remove(webSocket);
  _logger.LogInformation($"Websocket client closed.");
 }

private void MessageRoute(Message message)
 {
  var client = WebsocketClientCollection.Get(message.SendClientId);
  switch (message.action)
  {
  case "join":
   client.RoomNo = message.msg;
   client.SendMessageAsync($"{message.nick} join room {client.RoomNo} success .");
   _logger.LogInformation($"Websocket client {message.SendClientId} join room {client.RoomNo}.");
   break;
  case "send_to_room":
   if (string.IsNullOrEmpty(client.RoomNo))
   {
   break;
   }
   var clients = WebsocketClientCollection.GetRoomClients(client.RoomNo);
   clients.ForEach(c =>
   {
   c.SendMessageAsync(message.nick + " : " + message.msg);
   });
   _logger.LogInformation($"Websocket client {message.SendClientId} send message {message.msg} to room {client.RoomNo}");

   break;
  case "leave":
   var roomNo = client.RoomNo;
   client.RoomNo = "";
   client.SendMessageAsync($"{message.nick} leave room {roomNo} success .");
   _logger.LogInformation($"Websocket client {message.SendClientId} leave room {roomNo}");
   break;
  default:
   break;
  }
 }

 public class WebsocketClientCollection
 {
 private static List<WebsocketClient> _clients = new List<WebsocketClient>();

 public static void Add(WebsocketClient client)
 {
  _clients.Add(client);
 }

 public static void Remove(WebsocketClient client)
 {
  _clients.Remove(client);
 }

 public static WebsocketClient Get(string clientId)
 {
  var client = _clients.FirstOrDefault(c=>c.Id == clientId);

  return client;
 }

 public static List<WebsocketClient> GetRoomClients(string roomNo)
 {
  var client = _clients.Where(c => c.RoomNo == roomNo);
  return client.ToList();
 }
 }

 app.UseWebSockets(new WebSocketOptions
  {
  KeepAliveInterval = TimeSpan.FromSeconds(60),
  ReceiveBufferSize = 1* 1024
  });
 app.UseMiddleware<WebsocketHandlerMiddleware>();

<div style="margin-bottom:5px;">
 room no: <input type="text" id="txtRoomNo" value="8888"/> <button id="btnJoin">join room</button> <button id="btnLeave">leave room</button>
</div>
<div style="margin-bottom:5px;">
 nick name: <input type="text" id="txtNickName" value="batman" /> 
</div>
<div style="height:300px;width:600px">
 <textarea style="height:100%;width:100%" id="msgList"></textarea>
 <div style="text-align: right">
 <input type="text" id="txtMsg" value="" /> <button id="btnSend">send</button>
 </div>
</div>

var server = 'ws://localhost:5000'; //如果开启了https则这里是wss

var WEB_SOCKET = new WebSocket(server + '/ws');

WEB_SOCKET.onopen = function (evt) {
 console.log('Connection open ...');
 $('#msgList').val('websocket connection opened .');
};

WEB_SOCKET.onmessage = function (evt) {
 console.log('Received Message: ' + evt.data);
 if (evt.data) {
 var content = $('#msgList').val();
 content = content + '\r\n' + evt.data;

 $('#msgList').val(content);
 }
};

WEB_SOCKET.onclose = function (evt) {
 console.log('Connection closed.');
};

$('#btnJoin').on('click', function () {
 var roomNo = $('#txtRoomNo').val();
 var nick = $('#txtNickName').val();
 if (roomNo) {
 var msg = {
  action: 'join',
  msg: roomNo,
  nick: nick
 };
 WEB_SOCKET.send(JSON.stringify(msg));
 }
});

$('#btnSend').on('click', function () {
 var message = $('#txtMsg').val();
 var nick = $('#txtNickName').val();
 if (message) {
 WEB_SOCKET.send(JSON.stringify({
  action: 'send_to_room',
  msg: message,
  nick: nick
 }));
 }
});

$('#btnLeave').on('click', function () {
 var nick = $('#txtNickName').val();
 var msg = {
 action: 'leave',
 msg: '',
 nick: nick
 };
 WEB_SOCKET.send(JSON.stringify(msg));
});