private async Task ReadResponseAsync(WebSocketHandshake handshake, Stream stream)
{
var bufferSize = this.options.BufferManager.LargeBufferSize;
using (var reader = new StreamReader(stream, Encoding.ASCII, false, bufferSize, leaveOpen: true))
{
var responseHeaders = handshake.Response.Headers;
var responseLine = await reader.ReadLineAsync().ConfigureAwait(false) ?? string.Empty;
if (HttpHelper.TryParseHttpResponse(responseLine, out handshake.Response.Status, out handshake.Response.StatusDescription) == false)
{
if (string.IsNullOrEmpty(responseLine))
{
throw new WebSocketException("Empty response. Probably connection is closed by remote party.");
}
else
{
throw new WebSocketException($"Invalid handshake response: {responseLine}.");
}
}
if (handshake.Response.Status != HttpStatusCode.SwitchingProtocols)
{
throw new WebSocketException($"Invalid handshake response: {responseLine}.");
}
var headerLine = await reader.ReadLineAsync().ConfigureAwait(false);
while (string.IsNullOrEmpty(headerLine) == false)
{
responseHeaders.TryParseAndAdd(headerLine);
headerLine = await reader.ReadLineAsync().ConfigureAwait(false);
}
handshake.Response.ThrowIfInvalid(handshake.ComputeHandshake());
}
ParseWebSocketExtensions(handshake);
SelectExtensions(handshake);
}
private void SendNegotiationResponse(WebSocketHandshake handshake, StreamWriter writer)
{
writer.Write("HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\n");
if (handshake.Response.Cookies.Count > 0)
{
foreach (var cookie in handshake.Response.Cookies)
{
writer.Write("Set-Cookie: ");
writer.Write(cookie.ToString());
writer.Write("\r\n");
}
}
writer.Write("Sec-WebSocket-Accept: ");
writer.Write(handshake.ComputeHandshake());
// https://tools.ietf.org/html/rfc6455#section-4.2.2
/*
* Sec-WebSocket-Protocol
* If the client's handshake did not contain such a header field or if
* the server does not agree to any of the client's requested
* subprotocols, the only acceptable value is null. The absence
* of such a field is equivalent to the null value (meaning that
* if the server does not wish to agree to one of the suggested
* subprotocols, it MUST NOT send back a |Sec-WebSocket-Protocol|
* header field in its response).
*/
if (handshake.Response.Headers.Contains(ResponseHeader.WebSocketProtocol))
{
writer.Write("\r\nSec-WebSocket-Protocol: ");
writer.Write(handshake.Response.Headers[ResponseHeader.WebSocketProtocol]);
}
WriteHandshakeCookies(handshake, writer);
writer.Write("\r\n\r\n");
}