public static byte[] GenerateResponseHandshake(ClientHandshake clientHandshake)
{
var responseHandshake = new ServerHandshake();
responseHandshake.Location = "ws://" + clientHandshake.Host + clientHandshake.ResourcePath;
responseHandshake.Origin = clientHandshake.Origin;
responseHandshake.SubProtocol = clientHandshake.SubProtocol;
var challenge = new byte[8];
Array.Copy(clientHandshake.ChallengeBytes.Array, clientHandshake.ChallengeBytes.Offset, challenge, 0, 8);
responseHandshake.AnswerBytes = CalculateAnswerBytes(clientHandshake.Key1, clientHandshake.Key2, clientHandshake.ChallengeBytes);
return CreateServerHandshake(responseHandshake);
}
public static ClientHandshake ParseClientHandshake(ArraySegment<byte> byteShake)
{
// the "grammar" of the handshake
var pattern = @"^(?<connect>[^\s]+)\s(?<path>[^\s]+)\sHTTP\/1\.1\r\n" + // request line
@"((?<field_name>[^:\r\n]+):\s(?<field_value>[^\r\n]+)\r\n)+"; // unordered set of fields (name-chars colon space any-chars cr lf)
// subtract the challenge bytes from the handshake
var handshake = new ClientHandshake();
ArraySegment<byte> challenge = new ArraySegment<byte>(byteShake.Array, byteShake.Count - 8, 8); // -8 : eight byte challenge
handshake.ChallengeBytes = challenge;
// get the rest of the handshake
var utf8_handshake = Encoding.UTF8.GetString(byteShake.Array, 0, byteShake.Count - 8);
// match the handshake against the "grammar"
var regex = new Regex(pattern, RegexOptions.IgnoreCase);
var match = regex.Match(utf8_handshake);
var fields = match.Groups;
// save the request path
handshake.ResourcePath = fields["path"].Value;
// run through every match and save them in the handshake object
for (int i = 0; i < fields["field_name"].Captures.Count; i++)
{
var name = fields["field_name"].Captures[i].ToString();
var value = fields["field_value"].Captures[i].ToString();
switch (name.ToLower())
{
case "sec-websocket-key1":
handshake.Key1 = value;
break;
case "sec-websocket-key2":
handshake.Key2 = value;
break;
case "sec-websocket-protocol":
handshake.SubProtocol = value;
break;
case "origin":
handshake.Origin = value;
break;
case "host":
handshake.Host = value;
break;
case "cookie":
// create and fill a cookie collection from the data in the handshake
handshake.Cookies = new HttpCookieCollection();
var cookies = value.Split(';');
foreach (var item in cookies)
{
// the name if before the '=' char
var c_name = item.Remove(item.IndexOf('='));
// the value is after
var c_value = item.Substring(item.IndexOf('=') + 1);
// put the cookie in the collection (this also parses the sub-values and such)
handshake.Cookies.Add(new HttpCookie(c_name.TrimStart(), c_value));
}
break;
default:
// some field that we don't know about
if (handshake.AdditionalFields == null)
handshake.AdditionalFields = new Dictionary<string, string>();
handshake.AdditionalFields[name] = value;
break;
}
}
return handshake;
}
/// <summary>
/// Establishes the connection
/// </summary>
public void Connect()
{
string host = uri.Host;
StringBuilder path = new StringBuilder(uri.AbsolutePath);
if (path.Length == 0)
{
path.Append('/');
}
string query = uri.Query;
if (!string.IsNullOrEmpty(query))
{
path.Append("?");
path.Append(query);
}
string origin = "http://" + host;
networkStream = CreateSocket();
if (networkStream != null)
{
if (uri.Port != 80)
{
host = host + ":" + uri.Port;
}
ClientHandshake shake = new ClientHandshake();
shake.Host = host;
shake.Origin = origin;
shake.AdditionalFields = headers;
shake.Key1 = Guid.NewGuid().ToString();
shake.Key2 = Guid.NewGuid().ToString();
shake.Key1 = shake.Key1.Replace('-', ' ').Substring(0, 10);
shake.Key2 = shake.Key2.Replace('-', ' ').Substring(0, 10);
var baseChallenge = Guid.NewGuid().ToString().Substring(0, 8);
var challenge = baseChallenge.Substring(0, 2) + " " + baseChallenge.Substring(3, 2) + " " + baseChallenge.Substring(5, 2);
shake.ChallengeBytes = new ArraySegment<byte>(Encoding.UTF8.GetBytes(challenge));
shake.ResourcePath = path.ToString();
//outputStream = new StreamWriter(networkStream, Encoding.UTF8);
var response = shake.ToString();
byte[] encodedHandshake = Encoding.UTF8.GetBytes(response);
networkStream.Write(encodedHandshake, 0, encodedHandshake.Length);
networkStream.Flush();
//This needs to be implemented for security
// var expectedAnswer = Encoding.UTF8.GetString(HandshakeHelper.CalculateAnswerBytes(shake.Key1, shake.Key2, shake.ChallengeBytes));
inputStream = new StreamReader(networkStream);
//var input = inputStream.ReadToEnd();
string header = inputStream.ReadLine();
if (!header.Equals("HTTP/1.1 101 WebSocket Protocol Handshake"))
{
if (OnError != null)
OnError(new InvalidOperationException("Invalid handshake response"));
throw new InvalidOperationException("Invalid handshake response");
}
header = inputStream.ReadLine();
if (!header.Equals("Upgrade: WebSocket"))
{
if (OnError != null)
OnError(new InvalidOperationException("Invalid handshake response"));
throw new InvalidOperationException("Invalid handshake response");
}
header = inputStream.ReadLine();
if (!header.Equals("Connection: Upgrade"))
{
if (OnError != null)
OnError(new InvalidOperationException("Invalid handshake response"));
throw new InvalidOperationException("Invalid handshake response");
}
// Ignore any further response
do
{
header = inputStream.ReadLine();
} while (!header.Equals(""));
handshakeComplete = true;
connection = new WebSocketConnection(networkStream, isSocketIo);
SubscribeToConnectionEvents();
}
else
{
throw new InvalidOperationException("Could not create socket");
}
}
