public WebSocketFrame(EFrameType frameType, bool maskFlag, byte[] message, bool isFinal)
{
FrameType = frameType;
MaskFlag = maskFlag;
Message = message;
IsFinal = isFinal;
}
public static WebSocketFrame DecodeFrame(Stream inputStream)
{
using (EneterTrace.Entering())
{
try
{
// Note: Do not enclose the BinaryReader with using because it will close the stream!!!
BinaryReader aReader = new BinaryReader(inputStream);
// Read the first 2 bytes.
byte[] aFirst2Bytes = aReader.ReadBytes(2);
if (aFirst2Bytes.Length < 2)
{
throw new EndOfStreamException("End of stream during reading first two bytes of web socket frame.");
}
// Get if final.
bool anIsFinal = (aFirst2Bytes[0] & 0x80) != 0;
// Get opcode.
EFrameType aFrameType = (EFrameType)(aFirst2Bytes[0] & 0xF);
// Get if masked.
bool anIsMasked = (aFirst2Bytes[1] & 0x80) != 0;
// Get the message length.
int aMessageLength = aFirst2Bytes[1] & 0x7F;
if (aMessageLength == 126)
{
// The length is encoded in next 2 bytes (16 bits).
ushort aLength = aReader.ReadUInt16();
// Websockets are in big endians, so convert it to little endian.
aMessageLength = ConvertEndian(aLength);
}
else
if (aMessageLength == 127)
{
// The length is encoded in next 8 bytes (64 bits).
ulong aLength = aReader.ReadUInt64();
// Websockets are in big endians, so convert it to little endian.
aLength = ConvertEndian(aLength);
aMessageLength = (int)aLength;
}
// Get mask bytes.
byte[] aMaskBytes = null;
if (anIsMasked)
{
aMaskBytes = aReader.ReadBytes(4);
if (aMaskBytes.Length < 4)
{
throw new EndOfStreamException("End of stream during reading web socket mask bytes.");
}
}
// Get the message data.
byte[] aMessageData = aReader.ReadBytes(aMessageLength);
if (aMessageData.Length < aMessageLength)
{
throw new EndOfStreamException("End of stream during reading message data from the web socket frame.");
}
// If mask was used then unmask data.
if (anIsMasked)
{
for (int i = 0; i < aMessageData.Length; ++i)
{
aMessageData[i] = (byte)(aMessageData[i] ^ aMaskBytes[i % 4]);
}
}
WebSocketFrame aFrame = new WebSocketFrame(aFrameType, anIsMasked, aMessageData, anIsFinal);
return(aFrame);
}
catch (EndOfStreamException)
{
// End of the stream.
return(null);
}
catch (ObjectDisposedException)
{
// End of the stream.
return(null);
}
}
}
