public async static Task <WebSocketBase> ConnectAsync(Uri uri, WebSocketClientOptions options = null, CancellationToken cancellationToken = default)
{
if (uri == null)
{
throw new ArgumentNullException(nameof(uri));
}
if (!uri.IsAbsoluteUri)
{
throw new ArgumentException("This operation is not supported for a relative uri.");
}
else if (uri.Scheme != "ws" && uri.Scheme != "wss")
{
throw new ArgumentException("Only remote addresses starting with 'ws://' or 'wss://' are supported.");
}
if (options == null)
{
options = new WebSocketClientOptions();
}
// In case of error, we need to do clean up to make sure we don't leak anything
Stream connectedSocketStream = null;
try
{
// Connect to the remote server
var connectedSocket = await ConnectSocketAsync(uri.Host, uri.Port, cancellationToken).ConfigureAwait(false);
connectedSocketStream = new WebSocketNetworkStream(connectedSocket);
// Upgrade to SSL if needed
if (uri.Scheme == "wss")
{
connectedSocketStream = new SslStream(connectedSocketStream);
await((SslStream)connectedSocketStream).AuthenticateAsClientAsync(uri.Host, null, SslProtocols.Tls11 | SslProtocols.Tls12, checkCertificateRevocation: false).ConfigureAwait(false);
}
// Create the security key and expected response, then build all of the request headers
var secKeyAndSecWebSocketAccept = CreateSecKeyAndSecWebSocketAccept();
var requestHeader = BuildRequestHeader(uri, options.Headers, secKeyAndSecWebSocketAccept.Key, options.EnableMessageCompression);
// Write out the header to the connection
await connectedSocketStream.WriteAsync(requestHeader, 0, requestHeader.Length, cancellationToken).ConfigureAwait(false);
// Parse the response and store our state for the remainder of the connection
var responseHeaders = await ParseAndValidateConnectResponseAsync(connectedSocketStream, secKeyAndSecWebSocketAccept.Value, cancellationToken).ConfigureAwait(false);
var flags = default(WebSocketFlags);
var ip = ((IPEndPoint)connectedSocket.RemoteEndPoint).Address;
if (responseHeaders.TryGetValue(WebSocketHeaders.SecWebSocketExtensions, out var extensions) && extensions.IndexOf("permessage-deflate", StringComparison.OrdinalIgnoreCase) >= 0)
{
flags |= WebSocketFlags.PerMessageDeflate;
}
var proxy = new WebSocketStreamProxy(connectedSocketStream);
connectedSocketStream = null;
return(new WebSocket(proxy, flags, ip));
}
finally
{
if (connectedSocketStream != null)
{
connectedSocketStream.Dispose();
}
}
}
public WriteAsyncResult(WebSocketNetworkStream stream)
{
Stream = stream;
}
