public void Write(WsOpCode opCode, byte[] payload, bool isLastFrame)
{
//best to write everything to a memory stream before we push it onto the wire
//not really necessary but good advice
using (MemoryStream memoryStream = new MemoryStream()) {
byte finBitSetAsByte = isLastFrame ? (byte)0x80 : (byte)0x00;
byte byte1 = (byte)(finBitSetAsByte | (byte)opCode);
memoryStream.WriteByte(byte1);
//Don't set the mask flag. No need to mask data from server to client
//Depending on the size of the length we want to write it as a byte, ushort, or ulong.
if (payload.Length < 126)
{
memoryStream.WriteByte((byte)payload.Length);
}
else if (payload.Length <= ushort.MaxValue)
{
memoryStream.WriteByte(126);
BinaryReaderWriter.WriteUShort((ushort)payload.Length, memoryStream, false);
}
else
{
memoryStream.WriteByte(127);
BinaryReaderWriter.WriteULong((ulong)payload.Length, memoryStream, false);
}
memoryStream.Write(payload, 0, payload.Length);
byte[] buffer = memoryStream.ToArray();
_stream.Write(buffer, 0, buffer.Length);
}
}
public WsFrame Read(Stream stream, Socket socket)
{
byte byte1;
try {
byte1 = (byte)stream.ReadByte();
} catch (IOException) {
if (socket.Connected)
{
throw;
}
else
{
return(null);
}
}
//process first first byte
byte finBitFlag = 0x80;
byte opCodeFlag = 0x0F;
bool isFinBitSet = (byte1 & finBitFlag) == finBitFlag;
WsOpCode opCode = (WsOpCode)(byte1 & opCodeFlag);
//reade and process second byte
byte byte2 = (byte)stream.ReadByte();
byte maskFlag = 0x80;
bool isMaskBitSet = (byte2 & maskFlag) == maskFlag;
uint len = ReadLength(byte2, stream);
byte[] decodePayload;
//use the masking key to decode the data if needed
if (isMaskBitSet)
{
const int maskKeyLen = 4;
byte[] maskKey = BinaryReaderWriter.ReadExactly(maskKeyLen, stream);
byte[] encodePayload = BinaryReaderWriter.ReadExactly((int)len, stream);
decodePayload = new byte[len];
//apply the mask key
for (int i = 0; i < encodePayload.Length; i++)
{
decodePayload[i] = (byte)(encodePayload[i] ^ maskKey[i % maskKeyLen]);
}
}
else
{
decodePayload = BinaryReaderWriter.ReadExactly((int)len, stream);
}
WsFrame frame = new WsFrame(isFinBitSet, opCode, decodePayload, true);
return(frame);
}
private static uint ReadLength(byte byte2, Stream stream)
{
byte payloadLenFlag = 0x7F;
uint len = (uint)(byte2 & payloadLenFlag);
//read a short length or a long length depending on the value of len
if (len == 126)
{
len = BinaryReaderWriter.ReadUShortExactly(stream, false);
}
else if (len == 127)
{
len = (uint)BinaryReaderWriter.ReadULongExactly(stream, false);
const uint maxLen = 2147483648; //2GB
//protect ourselves against bad data
if (len > maxLen)
{
throw new ArgumentOutOfRangeException(string.Format("Payload length out of range. Min 0 Max 2GB. Actual {0:#,##0} bytes.", len));
}
}
return(len);
}
