/// NOTE: pong payload must be 125 bytes or less
/// Pong should contain the same payload as the ping
private async Task SendPongAsync(ArraySegment <byte> payload, CancellationToken cancellationToken)
{
// as per websocket spec
if (payload.Count > MAX_PING_PONG_PAYLOAD_LEN)
{
Exception ex = new InvalidOperationException($"Max ping message size {MAX_PING_PONG_PAYLOAD_LEN} exceeded: {payload.Count}");
await CloseOutputAutoTimeoutAsync(WebSocketCloseStatus.ProtocolError, ex.Message, ex);
throw ex;
}
try
{
if (_state == WebSocketState.Open)
{
using (MemoryStream stream = _recycledStreamFactory())
{
WebSocketFrameWriter.Write(WebSocketOpCode.Pong, payload, stream, true, _isClient);
await WriteStreamToNetwork(stream, cancellationToken);
}
}
}
catch (Exception ex)
{
await CloseOutputAutoTimeoutAsync(WebSocketCloseStatus.EndpointUnavailable, "Unable to send Pong response", ex);
throw;
}
}
/// <summary>
/// Called when a Close frame is received
/// Send a response close frame if applicable
/// </summary>
private async Task <WebSocketReceiveResult> RespondToCloseFrame(WebSocketFrame frame, ArraySegment <byte> buffer, CancellationToken token)
{
_closeStatus = frame.CloseStatus;
_closeStatusDescription = frame.CloseStatusDescription;
if (_state == WebSocketState.CloseSent)
{
// this is a response to close handshake initiated by this instance
_state = WebSocketState.Closed;
}
else if (_state == WebSocketState.Open)
{
// do not echo the close payload back to the client, there is no requirement for it in the spec.
// However, the same CloseStatus as recieved should be sent back.
ArraySegment <byte> closePayload = new ArraySegment <byte>(new byte[0], 0, 0);
_state = WebSocketState.CloseReceived;
using (MemoryStream stream = _recycledStreamFactory())
{
WebSocketFrameWriter.Write(WebSocketOpCode.ConnectionClose, closePayload, stream, true, _isClient);
await WriteStreamToNetwork(stream, token);
}
}
return(new WebSocketReceiveResult(frame.Count, WebSocketMessageType.Close, frame.IsFinBitSet, frame.CloseStatus, frame.CloseStatusDescription));
}
/// <summary>
/// Send data to the web socket
/// </summary>
/// <param name="buffer">the buffer containing data to send</param>
/// <param name="messageType">The message type. Can be Text or Binary</param>
/// <param name="endOfMessage">True if this message is a standalone message (this is the norm)
/// If it is a multi-part message then false (and true for the last message)</param>
/// <param name="cancellationToken">the cancellation token</param>
public override async Task SendAsync(ArraySegment <byte> buffer, WebSocketMessageType messageType, bool endOfMessage, CancellationToken cancellationToken)
{
using (MemoryStream stream = _recycledStreamFactory())
{
WebSocketOpCode opCode = GetOppCode(messageType);
if (_usePerMessageDeflate)
{
// NOTE: Compression is currently work in progress and should NOT be used in this library.
// The code below is very inefficient for small messages. Ideally we would like to have some sort of moving window
// of data to get the best compression. And we don't want to create new buffers which is bad for GC.
using (MemoryStream temp = new MemoryStream())
{
DeflateStream deflateStream = new DeflateStream(temp, CompressionMode.Compress);
deflateStream.Write(buffer.Array, buffer.Offset, buffer.Count);
deflateStream.Flush();
var compressedBuffer = new ArraySegment <byte>(temp.ToArray());
WebSocketFrameWriter.Write(opCode, compressedBuffer, stream, endOfMessage, _isClient);
}
}
else
{
WebSocketFrameWriter.Write(opCode, buffer, stream, endOfMessage, _isClient);
}
await WriteStreamToNetwork(stream, cancellationToken);
_isContinuationFrame = !endOfMessage; // TODO: is this correct??
}
}
/// <summary>
/// Polite close (use the close handshake)
/// </summary>
public override async Task CloseAsync(WebSocketCloseStatus closeStatus, string statusDescription, CancellationToken cancellationToken)
{
if (_state == WebSocketState.Open)
{
using (MemoryStream stream = _recycledStreamFactory())
{
ArraySegment <byte> buffer = BuildClosePayload(closeStatus, statusDescription);
WebSocketFrameWriter.Write(WebSocketOpCode.ConnectionClose, buffer, stream, true, _isClient);
await WriteStreamToNetwork(stream, cancellationToken);
_state = WebSocketState.CloseSent;
}
}
}
/// <summary>
/// Call this automatically from server side each keepAliveInterval period
/// NOTE: ping payload must be 125 bytes or less
/// </summary>
public async Task SendPingAsync(ArraySegment <byte> payload, CancellationToken cancellationToken)
{
if (payload.Count > MAX_PING_PONG_PAYLOAD_LEN)
{
throw new InvalidOperationException($"Cannot send Ping: Max ping message size {MAX_PING_PONG_PAYLOAD_LEN} exceeded: {payload.Count}");
}
if (_state == WebSocketState.Open)
{
using (MemoryStream stream = _recycledStreamFactory())
{
WebSocketFrameWriter.Write(WebSocketOpCode.Ping, payload, stream, true, _isClient);
await WriteStreamToNetwork(stream, cancellationToken);
}
}
}
/// <summary>
/// Fire and forget close
/// </summary>
public override async Task CloseOutputAsync(WebSocketCloseStatus closeStatus, string statusDescription, CancellationToken cancellationToken)
{
if (_state == WebSocketState.Open)
{
_state = WebSocketState.Closed; // set this before we write to the network because the write may fail
using (MemoryStream stream = _recycledStreamFactory())
{
ArraySegment <byte> buffer = BuildClosePayload(closeStatus, statusDescription);
WebSocketFrameWriter.Write(WebSocketOpCode.ConnectionClose, buffer, stream, true, _isClient);
await WriteStreamToNetwork(stream, cancellationToken).ConfigureAwait(false);
}
}
// cancel pending reads
_internalReadCts.Cancel();
}
/// <summary>
/// Polite close (use the close handshake)
/// </summary>
public override async Task CloseAsync(WebSocketCloseStatus closeStatus, string statusDescription, CancellationToken cancellationToken)
{
if (_state == WebSocketState.Open)
{
using (MemoryStream stream = _recycledStreamFactory())
{
ArraySegment <byte> buffer = BuildClosePayload(closeStatus, statusDescription);
WebSocketFrameWriter.Write(WebSocketOpCode.ConnectionClose, buffer, stream, true, _isClient);
Events.Log.CloseHandshakeStarted(_guid, closeStatus, statusDescription);
Events.Log.SendingFrame(_guid, WebSocketOpCode.ConnectionClose, true, buffer.Count, true);
await WriteStreamToNetwork(stream, cancellationToken);
_state = WebSocketState.CloseSent;
}
}
else
{
Events.Log.InvalidStateBeforeClose(_guid, _state);
}
}