@superhero/websocket
Version:
Websocket implementation
71 lines (58 loc) • 2.92 kB
Markdown
https://tools.ietf.org/html/rfc6455#section-5.2
```
0 1 2 3
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-------+-+-------------+-------------------------------+
|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| | |
+-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
4 5 6 7
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
| Extended payload length continued, if payload len == 127 |
+ - - - - - - - - - - - - - - - +-------------------------------+
8 9 10 11
+ - - - - - - - - - - - - - - - +-------------------------------+
| |Masking-key, if MASK set to 1 |
+-------------------------------+-------------------------------+
12 13 14 15
+-------------------------------+-------------------------------+
| Masking-key (continued) | Payload Data |
+-------------------------------- - - - - - - - - - - - - - - - +
: Payload Data continued ... :
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
| Payload Data continued ... |
+---------------------------------------------------------------+
```
https://tools.ietf.org/html/rfc6455#page-6
> The first piece of information comes from the |Sec-WebSocket-Key| header
field in the client handshake:
>
> Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
>
For this header field, the server has to take the value (as present
in the header field, e.g., the base64-encoded [RFC4648] version minus
any leading and trailing whitespace) and concatenate this with the
Globally Unique Identifier (GUID, [RFC4122]) "258EAFA5-E914-47DA-
95CA-C5AB0DC85B11" in string form, ... A SHA-1 hash (160 bits) [FIPS.180-3],
base64-encoded, of this concatenation is then returned in the server's
handshake.
### Respons header
The above generated key is past down through the `Sec-WebSocket-Accept` header.
```
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
```
https://tools.ietf.org/html/rfc6455#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. See Section 5.3 for further information on client-
to-server masking.
https://tools.ietf.org/html/rfc6455#section-5.3