Function wsFillFrameHeader

ws.go:562–596

(fh []byte, compressed bool, frameType wsOpCode, l int)

}

func wsFillFrameHeader(fh []byte, compressed bool, frameType wsOpCode, l int) (int, []byte) {
	var n int
	b := byte(frameType)
	b |= wsFinalBit
	if compressed {
		b |= wsRsv1Bit
	}
	b1 := byte(wsMaskBit)
	switch {
	case l <= 125:
		n = 2
		fh[0] = b
		fh[1] = b1 | byte(l)
	case l < 65536:
		n = 4
		fh[0] = b
		fh[1] = b1 | 126
		binary.BigEndian.PutUint16(fh[2:], uint16(l))
	default:
		n = 10
		fh[0] = b
		fh[1] = b1 | 127
		binary.BigEndian.PutUint64(fh[2:], uint64(l))
	}
	var key []byte
	var keyBuf [4]byte
	if _, err := io.ReadFull(rand.Reader, keyBuf[:4]); err != nil {
		kv := mrand.Int31()
		binary.LittleEndian.PutUint32(keyBuf[:4], uint32(kv))
	}
	copy(fh[n:], keyBuf[:4])
	key = fh[n : n+4]
	n += 4
	return n, key
}

func (nc *Conn) wsInitHandshake(u *url.URL) error {
	compress := nc.Opts.Compression