public async Task OpenAsync(string uri)
{
if (Opened)
{
throw new ApplicationException("WebSocket is already opened.");
}
Uri u = new Uri(uri);
HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Get, uri);
byte[] nonce = new byte[16];
new Random().NextBytes(nonce);
string requestKey = Convert.ToBase64String(nonce);
req.Headers.Add("Host", u.Host);
req.Headers.Add("User-Agent", UserAgent);
req.Headers.Add("Accept", "text/html");
req.Headers.Add("Sec-WebSocket-Version", "13");
req.Headers.Add("Origin", "null");
req.Headers.Add("Sec-WebSocket-Key", requestKey);
req.Headers.Add("Connection", "keep-alive, Upgrade");
req.Headers.Add("Pragma", "no-cache");
req.Headers.Add("Cache-Control", "no-cache");
req.Headers.Add("Upgrade", "websocket");
StringWriter tmpWriter = new StringWriter();
tmpWriter.WriteLine($"{req.Method} {req.RequestUri.PathAndQuery} HTTP/1.1");
tmpWriter.WriteLine(req.Headers.ToString());
await st.WriteAsyncWithTimeout(tmpWriter.AsciiToByteArray(),
timeout : this.TimeoutOpen,
cancel : this.Cancel);
Dictionary <string, string> headers = new Dictionary <string, string>();
int num = 0;
int responseCode = 0;
StreamReader tmpReader = new StreamReader(st);
while (true)
{
string line = await WebSocketHelper.DoAsyncWithTimeout((procCancel) => tmpReader.ReadLineAsync(),
timeout : this.TimeoutOpen,
cancel : this.Cancel);
if (line == "")
{
break;
}
if (num == 0)
{
string[] tokens = line.Split(' ');
if (tokens[0] != "HTTP/1.1")
{
throw new ApplicationException($"Cannot establish the WebSocket Protocol. Response: \"{tokens}\"");
}
responseCode = int.Parse(tokens[1]);
}
else
{
string[] tokens = line.Split(':');
string name = tokens[0].Trim();
string value = tokens[1].Trim();
headers[name] = value;
}
num++;
}
if (responseCode != 101)
{
throw new ApplicationException($"Cannot establish the WebSocket Protocol. Perhaps the destination host does not support WebSocket. Wrong response code: \"{responseCode}\"");
}
if (headers["Upgrade"].Equals("websocket", StringComparison.InvariantCultureIgnoreCase) == false)
{
throw new ApplicationException($"Wrong Upgrade header: \"{headers["Upgrade"]}\"");
}
string acceptKey = headers["Sec-WebSocket-Accept"];
string keyCalcStr = requestKey + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
SHA1 sha1 = new SHA1Managed();
string acceptKey2 = Convert.ToBase64String(sha1.ComputeHash(keyCalcStr.AsciiToByteArray()));
if (acceptKey != acceptKey2)
{
throw new ApplicationException($"Wrong accept_key: \'{acceptKey}\'");
}
Opened = true;
}
