private async Task SendAsyncImpl <T>(WebSocketsFrame.OpCodes opCode, T message, WebSocketsFrame.FrameFlags flags) where T : struct, IMessageWriter
{
//TODO: come up with a better way of getting ordered access to the socket
var writeLock = GetWriteSemaphore();
bool haveLock = writeLock.Wait(0);
if (!haveLock)
{ // try to acquire asynchronously instead, then
await writeLock.WaitAsync();
}
try
{
WebSocketServer.WriteStatus(ConnectionType, $"Writing {opCode} message ({message.GetPayloadLength()} bytes)...");
await WebSocketProtocol.WriteAsync(this, opCode, flags, ref message);
if (opCode == WebSocketsFrame.OpCodes.Close)
{
connection.Output.Complete();
}
}
finally
{
writeLock.Release();
}
}
private async Task SendAsyncImpl <T>(WebSocketsFrame.OpCodes opCode, T message) where T : struct, IMessageWriter
{
//TODO: come up with a better way of getting ordered access to the socket
var writeLock = GetWriteSemaphore();
bool haveLock = writeLock.Wait(0);
if (!haveLock)
{ // try to acquire asynchronously instead, then
await writeLock.WaitAsync();
}
try
{
WebSocketServer.WriteStatus($"Writing {opCode} message...");
await WebSocketProtocol.WriteAsync(this, opCode, ref message);
if (opCode == WebSocketsFrame.OpCodes.Close)
{
Close();
}
}
finally
{
writeLock.Release();
}
}
private async void OnConnection(IChannel connection)
{
using (connection)
{
WebSocketConnection socket = null;
try
{
WriteStatus(ConnectionType.Server, "Connected");
WriteStatus(ConnectionType.Server, "Parsing http request...");
var request = await ParseHttpRequest(connection.Input);
try
{
WriteStatus(ConnectionType.Server, "Identifying protocol...");
socket = GetProtocol(connection, ref request);
WriteStatus(ConnectionType.Server, $"Protocol: {WebSocketProtocol.Name}");
WriteStatus(ConnectionType.Server, "Authenticating...");
if (!await OnAuthenticateAsync(socket, ref request.Headers))
{
throw new InvalidOperationException("Authentication refused");
}
WriteStatus(ConnectionType.Server, "Completing handshake...");
await WebSocketProtocol.CompleteServerHandshakeAsync(ref request, socket);
}
finally
{
request.Dispose(); // can't use "ref request" or "ref headers" otherwise
}
WriteStatus(ConnectionType.Server, "Handshake complete hook...");
await OnHandshakeCompleteAsync(socket);
connections.TryAdd(socket, socket);
WriteStatus(ConnectionType.Server, "Processing incoming frames...");
await socket.ProcessIncomingFramesAsync(this);
WriteStatus(ConnectionType.Server, "Exiting...");
await socket.CloseAsync();
}
catch (Exception ex)
{// meh, bye bye broken connection
try { socket?.Dispose(); } catch { }
WriteStatus(ConnectionType.Server, ex.StackTrace);
WriteStatus(ConnectionType.Server, ex.GetType().Name);
WriteStatus(ConnectionType.Server, ex.Message);
}
finally
{
WebSocketConnection tmp;
if (socket != null)
{
connections.TryRemove(socket, out tmp);
}
try { connection.Output.Complete(); } catch { }
try { connection.Input.Complete(); } catch { }
}
}
}
internal async Task ProcessIncomingFramesAsync(WebSocketServer server)
{
while (true)
{
var buffer = await connection.Input.ReadAsync();
try
{
if (buffer.IsEmpty && connection.Input.Reading.IsCompleted)
{
break; // that's all, folks
}
WebSocketsFrame frame;
if (WebSocketProtocol.TryReadFrameHeader(ref buffer, out frame))
{
int payloadLength = frame.PayloadLength;
// buffer now points to the payload
if (connectionType == ConnectionType.Server)
{
if (!frame.IsMasked)
{
throw new InvalidOperationException("Client-to-server frames should be masked");
}
}
else
{
if (frame.IsMasked)
{
throw new InvalidOperationException("Server-to-client frames should not be masked");
}
}
if (frame.IsControlFrame && !frame.IsFinal)
{
throw new InvalidOperationException("Control frames cannot be fragmented");
}
await OnFrameReceivedAsync(ref frame, ref buffer, server);
// and finally, progress past the frame
if (payloadLength != 0)
{
buffer = buffer.Slice(payloadLength);
}
}
}
finally
{
connection.Input.Advance(buffer.Start, buffer.End);
}
}
}
public static async Task <WebSocketConnection> ConnectAsync(
string location, string protocol = null, string origin = null,
Action <HttpRequestHeaders> addHeaders = null,
ChannelFactory channelFactory = null)
{
WebSocketServer.WriteStatus(ConnectionType.Client, $"Connecting to {location}...");
Uri uri;
if (!Uri.TryCreate(location, UriKind.Absolute, out uri) ||
uri.Scheme != "ws")
{
throw new ArgumentException(nameof(location));
}
IPAddress ip;
if (!IPAddress.TryParse(uri.Host, out ip))
{
throw new NotImplementedException("host must be an IP address at the moment, sorry");
}
WebSocketServer.WriteStatus(ConnectionType.Client, $"Opening socket to {ip}:{uri.Port}...");
var socket = await SocketConnection.ConnectAsync(new IPEndPoint(ip, uri.Port), channelFactory);
return(await WebSocketProtocol.ClientHandshake(socket, uri, origin, protocol));
}
internal static async Task <WebSocketConnection> ClientHandshake(IChannel channel, Uri uri, string origin, string protocol)
{
WebSocketServer.WriteStatus(ConnectionType.Client, "Writing client handshake...");
// write the outbound request portion of the handshake
var output = channel.Output.Alloc();
output.Write(GET);
output.WriteAsciiString(uri.PathAndQuery);
output.Write(HTTP_Host);
output.WriteAsciiString(uri.Host);
output.Write(UpgradeConnectionKey);
byte[] challengeKey = new byte[WebSocketProtocol.SecResponseLength];
GetRandomBytes(challengeKey); // we only want the first 16 for entropy, but... meh
output.Ensure(WebSocketProtocol.SecRequestLength);
int bytesWritten = Base64.Encode(new ReadOnlySpan <byte>(challengeKey, 0, 16), output.Memory);
// now cheekily use that data we just wrote the the output buffer
// as a source to compute the expected bytes, and store them back
// into challengeKey; sneaky!
WebSocketProtocol.ComputeReply(
output.Memory.Slice(0, WebSocketProtocol.SecRequestLength).Span,
challengeKey);
output.Advance(bytesWritten);
output.Write(CRLF);
if (!string.IsNullOrWhiteSpace(origin))
{
output.WriteAsciiString("Origin: ");
output.WriteAsciiString(origin);
output.Write(CRLF);
}
if (!string.IsNullOrWhiteSpace(protocol))
{
output.WriteAsciiString("Sec-WebSocket-Protocol: ");
output.WriteAsciiString(protocol);
output.Write(CRLF);
}
output.Write(WebSocketVersion);
output.Write(CRLF); // final CRLF to end the HTTP request
await output.FlushAsync();
WebSocketServer.WriteStatus(ConnectionType.Client, "Parsing response to client handshake...");
using (var resp = await WebSocketServer.ParseHttpResponse(channel.Input))
{
if (!resp.HttpVersion.Equals(ExpectedHttpVersion) ||
!resp.StatusCode.Equals(ExpectedStatusCode) ||
!resp.StatusText.Equals(ExpectedStatusText) ||
!resp.Headers.GetRaw("Upgrade").Equals(ExpectedUpgrade) ||
!resp.Headers.GetRaw("Connection").Equals(ExpectedConnection))
{
throw new InvalidOperationException("Not a web-socket server");
}
var accept = resp.Headers.GetRaw("Sec-WebSocket-Accept");
if (!accept.Equals(challengeKey))
{
throw new InvalidOperationException("Sec-WebSocket-Accept mismatch");
}
protocol = resp.Headers.GetAsciiString("Sec-WebSocket-Protocol");
}
var webSocket = new WebSocketConnection(channel, ConnectionType.Client)
{
Host = uri.Host,
RequestLine = uri.OriginalString,
Origin = origin,
Protocol = protocol
};
webSocket.StartProcessingIncomingFrames();
return(webSocket);
}
