Fixing WebSocketsTransport to handle exceptions correctly
Exceptions thrown when sending or receiving messages would leave the WebSockets transport in a half-closed state when one of the loops is closed but the other one is still running preventing from the Connection.Closed event to be fired. Fixes: #412
This commit is contained in:
Pawel Kadluczka
parent
fbf7e1fb72
commit
cb9f44ddf6
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@ -14,9 +14,9 @@ namespace Microsoft.AspNetCore.Sockets.Client
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{
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public class WebSocketsTransport : ITransport
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{
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private ClientWebSocket _webSocket = new ClientWebSocket();
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private readonly ClientWebSocket _webSocket = new ClientWebSocket();
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private IChannelConnection<SendMessage, Message> _application;
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private CancellationToken _cancellationToken = new CancellationToken();
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private readonly CancellationTokenSource _transportCts = new CancellationTokenSource();
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private readonly ILogger _logger;
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public WebSocketsTransport()
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@ -48,8 +48,8 @@ namespace Microsoft.AspNetCore.Sockets.Client
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_application = application;
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await Connect(url);
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var sendTask = SendMessages(url, _cancellationToken);
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var receiveTask = ReceiveMessages(url, _cancellationToken);
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var sendTask = SendMessages(url);
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var receiveTask = ReceiveMessages(url);
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// TODO: Handle TCP connection errors
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// https://github.com/SignalR/SignalR/blob/1fba14fa3437e24c204dfaf8a18db3fce8acad3c/src/Microsoft.AspNet.SignalR.Core/Owin/WebSockets/WebSocketHandler.cs#L248-L251
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@ -62,112 +62,131 @@ namespace Microsoft.AspNetCore.Sockets.Client
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}).Unwrap();
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}
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private async Task ReceiveMessages(Uri pollUrl, CancellationToken cancellationToken)
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private async Task ReceiveMessages(Uri pollUrl)
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{
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_logger.LogInformation("Starting receive loop");
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while (!cancellationToken.IsCancellationRequested)
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try
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{
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const int bufferSize = 4096;
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var totalBytes = 0;
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var incomingMessage = new List<ArraySegment<byte>>();
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WebSocketReceiveResult receiveResult;
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do
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while (!_transportCts.Token.IsCancellationRequested)
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{
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var buffer = new ArraySegment<byte>(new byte[bufferSize]);
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//Exceptions are handled above where the send and receive tasks are being run.
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receiveResult = await _webSocket.ReceiveAsync(buffer, cancellationToken);
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if (receiveResult.MessageType == WebSocketMessageType.Close)
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const int bufferSize = 4096;
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var totalBytes = 0;
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var incomingMessage = new List<ArraySegment<byte>>();
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WebSocketReceiveResult receiveResult;
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do
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{
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_logger.LogInformation("Websocket closed by the server. Close status {0}", receiveResult.CloseStatus);
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var buffer = new ArraySegment<byte>(new byte[bufferSize]);
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_application.Output.Complete();
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return;
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//Exceptions are handled above where the send and receive tasks are being run.
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receiveResult = await _webSocket.ReceiveAsync(buffer, _transportCts.Token);
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if (receiveResult.MessageType == WebSocketMessageType.Close)
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{
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_logger.LogInformation("Websocket closed by the server. Close status {0}", receiveResult.CloseStatus);
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_application.Output.Complete();
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return;
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}
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_logger.LogDebug("Message received. Type: {0}, size: {1}, EndOfMessage: {2}",
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receiveResult.MessageType.ToString(), receiveResult.Count, receiveResult.EndOfMessage);
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var truncBuffer = new ArraySegment<byte>(buffer.Array, 0, receiveResult.Count);
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incomingMessage.Add(truncBuffer);
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totalBytes += receiveResult.Count;
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} while (!receiveResult.EndOfMessage);
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//Making sure the message type is either text or binary
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Debug.Assert((receiveResult.MessageType == WebSocketMessageType.Binary || receiveResult.MessageType == WebSocketMessageType.Text), "Unexpected message type");
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Message message;
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var messageType = receiveResult.MessageType == WebSocketMessageType.Binary ? MessageType.Binary : MessageType.Text;
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if (incomingMessage.Count > 1)
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{
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var messageBuffer = new byte[totalBytes];
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var offset = 0;
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for (var i = 0; i < incomingMessage.Count; i++)
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{
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Buffer.BlockCopy(incomingMessage[i].Array, 0, messageBuffer, offset, incomingMessage[i].Count);
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offset += incomingMessage[i].Count;
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}
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message = new Message(messageBuffer, messageType, receiveResult.EndOfMessage);
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}
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else
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{
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var buffer = new byte[incomingMessage[0].Count];
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Buffer.BlockCopy(incomingMessage[0].Array, incomingMessage[0].Offset, buffer, 0, incomingMessage[0].Count);
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message = new Message(buffer, messageType, receiveResult.EndOfMessage);
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}
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_logger.LogDebug("Message received. Type: {0}, size: {1}, EndOfMessage: {2}",
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receiveResult.MessageType.ToString(), receiveResult.Count, receiveResult.EndOfMessage);
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var truncBuffer = new ArraySegment<byte>(buffer.Array, 0, receiveResult.Count);
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incomingMessage.Add(truncBuffer);
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totalBytes += receiveResult.Count;
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} while (!receiveResult.EndOfMessage);
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//Making sure the message type is either text or binary
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Debug.Assert((receiveResult.MessageType == WebSocketMessageType.Binary || receiveResult.MessageType == WebSocketMessageType.Text), "Unexpected message type");
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Message message;
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var messageType = receiveResult.MessageType == WebSocketMessageType.Binary ? MessageType.Binary : MessageType.Text;
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if (incomingMessage.Count > 1)
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{
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var messageBuffer = new byte[totalBytes];
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var offset = 0;
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for (var i = 0; i < incomingMessage.Count; i++)
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_logger.LogInformation("Passing message to application. Payload size: {0}", message.Payload.Length);
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while (await _application.Output.WaitToWriteAsync(_transportCts.Token))
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{
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Buffer.BlockCopy(incomingMessage[i].Array, 0, messageBuffer, offset, incomingMessage[i].Count);
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offset += incomingMessage[i].Count;
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}
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message = new Message(messageBuffer, messageType, receiveResult.EndOfMessage);
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}
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else
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{
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var buffer = new byte[incomingMessage[0].Count];
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Buffer.BlockCopy(incomingMessage[0].Array, incomingMessage[0].Offset, buffer, 0, incomingMessage[0].Count);
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message = new Message(buffer, messageType, receiveResult.EndOfMessage);
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}
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_logger.LogInformation("Passing message to application. Payload size: {0}", message.Payload.Length);
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while (await _application.Output.WaitToWriteAsync(cancellationToken))
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{
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if (_application.Output.TryWrite(message))
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{
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incomingMessage.Clear();
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break;
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if (_application.Output.TryWrite(message))
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{
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incomingMessage.Clear();
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break;
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}
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}
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}
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}
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_logger.LogInformation("Receive loop stopped");
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catch (OperationCanceledException)
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{
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}
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finally
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{
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_transportCts.Cancel();
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_logger.LogInformation("Receive loop stopped");
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}
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}
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private async Task SendMessages(Uri sendUrl, CancellationToken cancellationToken)
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private async Task SendMessages(Uri sendUrl)
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{
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_logger.LogInformation("Starting the send loop");
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while (await _application.Input.WaitToReadAsync(cancellationToken))
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try
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{
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while (_application.Input.TryRead(out SendMessage message))
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while (await _application.Input.WaitToReadAsync(_transportCts.Token))
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{
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try
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while (_application.Input.TryRead(out SendMessage message))
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{
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_logger.LogDebug("Received message from application. Message type {0}. Payload size: {1}",
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message.Type, message.Payload.Length);
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try
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{
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_logger.LogDebug("Received message from application. Message type {0}. Payload size: {1}",
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message.Type, message.Payload.Length);
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await _webSocket.SendAsync(new ArraySegment<byte>(message.Payload),
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message.Type == MessageType.Text ? WebSocketMessageType.Text : WebSocketMessageType.Binary,
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true, cancellationToken);
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await _webSocket.SendAsync(new ArraySegment<byte>(message.Payload),
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message.Type == MessageType.Text ? WebSocketMessageType.Text : WebSocketMessageType.Binary,
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true, _transportCts.Token);
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message.SendResult.SetResult(null);
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}
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catch (OperationCanceledException)
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{
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message.SendResult.SetCanceled();
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await _webSocket.CloseAsync(WebSocketCloseStatus.Empty, null, _cancellationToken);
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break;
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}
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catch (Exception ex)
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{
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_logger.LogError(ex.Message);
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message.SendResult.SetException(ex);
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await _webSocket.CloseAsync(WebSocketCloseStatus.Empty, null, _cancellationToken);
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throw;
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message.SendResult.SetResult(null);
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}
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catch (OperationCanceledException)
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{
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_logger.LogInformation("Sending a message canceled.");
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message.SendResult.SetCanceled();
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await CloseWebSocket();
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break;
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}
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catch (Exception ex)
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{
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_logger.LogError("Error while sending a message {0}", ex.Message);
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message.SendResult.SetException(ex);
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await CloseWebSocket();
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throw;
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}
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}
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}
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}
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_logger.LogInformation("Send loop stopped");
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catch (OperationCanceledException)
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{
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}
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finally
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{
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_transportCts.Cancel();
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_logger.LogInformation("Send loop stopped");
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}
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}
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private async Task Connect(Uri url)
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@ -182,14 +201,14 @@ namespace Microsoft.AspNetCore.Sockets.Client
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uriBuilder.Scheme = "wss";
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}
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await _webSocket.ConnectAsync(uriBuilder.Uri, _cancellationToken);
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await _webSocket.ConnectAsync(uriBuilder.Uri, CancellationToken.None);
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}
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public async Task StopAsync()
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{
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_logger.LogInformation("Transport {0} is stopping", nameof(WebSocketsTransport));
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await _webSocket.CloseAsync(WebSocketCloseStatus.Empty, null, _cancellationToken);
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await CloseWebSocket();
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_webSocket.Dispose();
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try
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@ -203,5 +222,25 @@ namespace Microsoft.AspNetCore.Sockets.Client
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_logger.LogInformation("Transport {0} stopped", nameof(WebSocketsTransport));
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}
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private async Task CloseWebSocket()
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{
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try
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{
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// Best effort - it's still possible (but not likely) that the transport is being closed via StopAsync
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// while the webSocket is being closed due to an error.
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if (_webSocket.State != WebSocketState.Closed)
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{
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_logger.LogInformation("Closing webSocket");
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await _webSocket.CloseAsync(WebSocketCloseStatus.Empty, null, CancellationToken.None);
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}
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}
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catch (Exception ex)
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{
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// This is benign - the exception can happen due to the race described above because we would
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// try closing the webSocket twice.
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_logger.LogInformation("Closing webSocket failed with {0}", ex);
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}
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}
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}
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}
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@ -52,7 +52,7 @@ namespace Microsoft.AspNetCore.SignalR.Tests
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const string message = "Hello, World!";
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using (var ws = new ClientWebSocket())
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{
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string socketUrl = _serverFixture.WebSocketsUrl + "/echo";
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var socketUrl = _serverFixture.WebSocketsUrl + "/echo";
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logger.LogInformation("Connecting WebSocket to {socketUrl}", socketUrl);
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await ws.ConnectAsync(new Uri(socketUrl), CancellationToken.None).OrTimeout();
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@ -0,0 +1,80 @@
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// Copyright (c) .NET Foundation. All rights reserved.
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// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
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using System;
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using System.Threading.Tasks;
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using System.Threading.Tasks.Channels;
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using Microsoft.AspNetCore.SignalR.Tests.Common;
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using Microsoft.AspNetCore.Sockets;
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using Microsoft.AspNetCore.Sockets.Client;
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using Microsoft.AspNetCore.Sockets.Internal;
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using Microsoft.AspNetCore.Testing.xunit;
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using Xunit;
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namespace Microsoft.AspNetCore.SignalR.Tests
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{
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[Collection(EndToEndTestsCollection.Name)]
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public class WebSocketsTransportTests
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{
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private readonly ServerFixture _serverFixture;
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public WebSocketsTransportTests(ServerFixture serverFixture)
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{
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if (serverFixture == null)
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{
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throw new ArgumentNullException(nameof(serverFixture));
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}
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_serverFixture = serverFixture;
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}
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[ConditionalFact]
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[OSSkipCondition(OperatingSystems.Windows, WindowsVersions.Win7, WindowsVersions.Win2008R2, SkipReason = "No WebSockets Client for this platform")]
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public async Task WebSocketsTransportStopsSendAndReceiveLoopsWhenTransportIsStopped()
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{
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var connectionToTransport = Channel.CreateUnbounded<SendMessage>();
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var transportToConnection = Channel.CreateUnbounded<Message>();
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var channelConnection = new ChannelConnection<SendMessage, Message>(connectionToTransport, transportToConnection);
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var webSocketsTransport = new WebSocketsTransport();
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await webSocketsTransport.StartAsync(new Uri(_serverFixture.WebSocketsUrl + "/echo"), channelConnection);
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await webSocketsTransport.StopAsync();
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await webSocketsTransport.Running.OrTimeout();
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}
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[ConditionalFact]
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[OSSkipCondition(OperatingSystems.Windows, WindowsVersions.Win7, WindowsVersions.Win2008R2, SkipReason = "No WebSockets Client for this platform")]
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public async Task WebSocketsTransportStopsWhenConnectionChannelClosed()
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{
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var connectionToTransport = Channel.CreateUnbounded<SendMessage>();
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var transportToConnection = Channel.CreateUnbounded<Message>();
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var channelConnection = new ChannelConnection<SendMessage, Message>(connectionToTransport, transportToConnection);
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var webSocketsTransport = new WebSocketsTransport();
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await webSocketsTransport.StartAsync(new Uri(_serverFixture.WebSocketsUrl + "/echo"), channelConnection);
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connectionToTransport.Out.TryComplete();
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await webSocketsTransport.Running.OrTimeout();
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}
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[ConditionalFact]
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[OSSkipCondition(OperatingSystems.Windows, WindowsVersions.Win7, WindowsVersions.Win2008R2, SkipReason = "No WebSockets Client for this platform")]
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public async Task WebSocketsTransportStopsWhenConnectionClosedByTheServer()
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{
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var connectionToTransport = Channel.CreateUnbounded<SendMessage>();
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var transportToConnection = Channel.CreateUnbounded<Message>();
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var channelConnection = new ChannelConnection<SendMessage, Message>(connectionToTransport, transportToConnection);
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var webSocketsTransport = new WebSocketsTransport();
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await webSocketsTransport.StartAsync(new Uri(_serverFixture.WebSocketsUrl + "/echo"), channelConnection);
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var sendTcs = new TaskCompletionSource<object>();
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connectionToTransport.Out.TryWrite(new SendMessage(new byte[] { 0x42 }, MessageType.Binary, sendTcs));
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await sendTcs.Task;
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// The echo endpoint close the connection immediately after sending response which should stop the transport
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await webSocketsTransport.Running.OrTimeout();
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Assert.True(transportToConnection.In.TryRead(out var message));
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Assert.Equal(new byte[] { 0x42 }, message.Payload);
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}
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}
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}
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