public static Frame FromBuffer(byte[] buffer)
{
var frame = new Frame();
// If no extended payload length and no mask are used, the payload starts at the 3rd byte
int payloadStartIndex = 2;
var firstNibble = (byte)(buffer[0] & 0xF0);
var secondNibble = (byte)(buffer[0] & 0x0F);
// When the first bit of the first byte is set,
// It means that the current frame is the final frame of a message
if (firstNibble == Fin)
frame.IsFin = true;
// The opcode consists of the last four bits in the first byte
frame.Opcode = (Opcodes)secondNibble;
// The last bit of the second byte is the masking bit
bool isMasked = Convert.ToBoolean((buffer[1] & 0x80) >> 7);
// Payload length is stored in the first seven bits of the second byte
var payloadLength = (ulong)(buffer[1] & 0x7F);
// From RFC-6455 - Section 5.2
// "If 126, the following 2 bytes interpreted as a 16-bit unsigned integer are the payload length
// (expressed in network byte order)"
if (payloadLength == TwoBytesLengthCode)
{
Array.Reverse(buffer, payloadStartIndex, 2);
payloadLength = BitConverter.ToUInt16(buffer, payloadStartIndex);
payloadStartIndex += 2;
}
// From RFC-6455 - Section 5.2
// "If 127, the following 8 bytes interpreted as a 64-bit unsigned integer (the most significant bit MUST be 0)
// are the payload length (expressed in network byte order)"
else if (payloadLength == EightBytesLengthCode)
{
Array.Reverse(buffer, payloadStartIndex, 8);
payloadLength = BitConverter.ToUInt64(buffer, payloadStartIndex);
payloadStartIndex += 8;
}
frame.PayloadLength = payloadLength;
// From RFC-6455 - Section 5.2
// "All frames sent from the client to the server are masked by a
// 32-bit value that is contained within the frame. This field is
// present if the mask bit is set to 1 and is absent if the mask bit
// is set to 0."
if (isMasked)
{
frame.MaskingKey = BitConverter.ToInt32(buffer, payloadStartIndex);
payloadStartIndex += 4;
}
var content = new byte[frame.PayloadLength];
Array.Copy(buffer, payloadStartIndex, content, 0, (int)frame.PayloadLength);
if (isMasked)
UnMask(content, frame.MaskingKey);
frame.UnmaskedPayload = content;
return frame;
}
public void Send(string data)
{
var frame = new Frame(Frame.Opcodes.Text, Encoding.UTF8.GetBytes(data), true);
Send(frame);
}
private void Send(Frame frame)
{
if (!m_isConnected)
return;
byte[] buffer = frame.ToBuffer();
var sendEventArgs = new SocketAsyncEventArgs();
sendEventArgs.SetBuffer(buffer, 0, buffer.Length);
m_tcpClient.Client.SendAsync(sendEventArgs);
}
public void Send(byte[] data)
{
var frame = new Frame(Frame.Opcodes.Binary, data, true);
Send(frame);
}