handshake(握手)
GET /chat HTTP/1.1
Host: server.example.com
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
Sec-WebSocket-Version: 13
server回复：
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
"dGhlIHNhbXBsZSBub25jZQ=="(Sec-WebSocket-Key)+"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"(因定GUID)
先SHA-1哈希，再用base64编码，得到"s3pPLMBiTxaQ9kYGzzhZRbK+xOo="
Framing Protocol(数据帧协议)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-------+-+-------------+-------------------------------+
|F|R|R|R| opcode|M| Payload len | Extended payload length |
|I|S|S|S| (4) |A| (7) | (16/64) |
|N|V|V|V| |S| | (if payload len==126/127) |
| |1|2|3| |K| | |
+-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
| Extended payload length continued, if payload len == 127 |
+ - - - - - - - - - - - - - - - +-------------------------------+
| |Masking-key, if MASK set to 1 |
+-------------------------------+-------------------------------+
| Masking-key (continued) | Payload Data |
+-------------------------------- - - - - - - - - - - - - - - - +
: Payload Data continued ... :
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
| Payload Data continued ... |
+---------------------------------------------------------------+
opcode:
0x1 text frame
0x2 binary frame
0x8 connection close
Mask:是否有掩码(client to server必须, server to client可选)
Payload length:负载长度
<=125 直接7位表示长度
126，表示长充大于125并小于0xFFFF,长度放在2Byte
127，长度放在后8Byte
Masking-key:如果有Mask,4Byte
Payload Data:如果有Mask,需要和Making-key做异或来还原数据
QByteArray handShake(QString secWebSocketKey)
{
Q_ASSERT(!secWebSocketKey.isEmpty());
secWebSocketKey += "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
QString s= QCryptographicHash::hash(secWebSocketKey.toAscii(),
QCryptographicHash::Sha1).toBase64();
QString respone = QString("HTTP/1.1 101 Switching Protocols\r\n"
"Upgrade: websocket\r\n"
"Connection: Upgrade\r\n"
"Access-Control-Allow-Credentials:true\r\n"
"Access-Control-Allow-Headers:content-type\r\n"
"Sec-WebSocket-Accept: %1\r\n"
"\r\n").arg(s);
return respone.toAscii();
}
void unmask (int pos, int len, unsigned char *buf)
{
int i = pos; //The position of payload data
int n = pos - 4; //The position of masking-key
for (; i<len; i++,n++)
{
if (n == pos) n = pos - 4; //back to the first masking-key
buf[i] ^= buf[n]; //unmask: payload data XOR masking-key
}
}
QByteArray parserData(QByteArray input)
{
unsigned char *buf=(unsigned char *)input.data();
QByteArray out;
int len = input.length();
if (buf[0] == 0x88)
{
qDebug()<<"Received a Close frame";
out = "close";
return out;
}
buf[1] &= 0x7F;
int payloadBegin = 0;
if (buf[1] < 126)
{
payloadBegin = 6;
}
else if (buf[1] == 126)
{
payloadBegin = 8; //6+2
}
else if (buf[1] == 127)
{
payloadBegin = 14;//6+8
}
unmask(payloadBegin, len, buf);
out = QByteArray::fromRawData((const char *)(input.data()+payloadBegin), input.size()-payloadBegin);
return out;
}
void writeData(QTcpSocket *socket, const QByteArray &data)
{
QByteArray head(2, 0);
if (data.length()<=125)
{
quint8 len = data.length();
head[1] = len;
}
else if (data.length()<=0xffff)
{
head[1] = 126;
quint16 len = data.length();
head.resize(4);
for (int i=3; i>1; i--)
{
head[i] = (byte)(len & 0xff);
len = len >> 8;
}
}
else{
head[1] = 127;
quint64 len = data.length();
head.resize(10);
for (int i=9; i>1; i--)
{
head[i] = (byte)(len & 0xff);
len = len >> 8;
}
}
socket->write(head);
socket->write(data);
socket->flush();
}