This is a note by pywebsocket developers for catching up changes on the spec and tracking discussion on HyBi. This may also be useful for people who are interested in WebSocket protocol design to quickly catch up the history of discussion on HyBi and understand what/why/when a certain decision has been made.
Protocol support status of pywebsocket
pywebsocket supports the following protocols.
and the following extension.
Official working drafts
HyBi 17
Note
- Only editorial changes
- Sec-WebSocket-Version value is still 13 and this must be the version for RFC
HyBi 16
Note
HyBi 15
Semantic changes
- If servers doesn't support the requested version, they MUST respond with Sec-WebSocket-Version headers containing all available versions.
- The servers MUST close the connection upon receiving a non-masked frame with status code of 1002.
- The clients MUST close the connection upon receiving a masked frame with status code of 1002.
Note
- Sec-WebSocket-Version is still 13.
HyBi 14
Semantic changes
- Extension values in extension-param could be quoted-string in addition to token.
- Clarify the way to support multiple versions of WebSocket protocol.
- Payload length MUST be encoded in minimal number of bytes.
- WebSocket MUST support TLS.
- Sec-WebSocket-Key and Sec-WebSocketAccept header field MUST NOT appear more than once.
- Sec-WebSocket-Extensions and Sec-WebSocket-Protocol header filed MAY appear multiple times in requests, but it MUST NOT appear more than once in responses.
- Sec-WebSocket-Version header filed MAY appear multiple times in responses, but it MUST NOT appear more than once in requests.
- Status code 1007 was changed.
Note
- Sec-WebSocket-Version is still 13.
HyBi 13
Semantic changes
- Sec-WebSocket-Version is 13.
- Clients must fail the connection on receiving a subprotocol indication that was not present in the client requests in the opening handshake.
- Status Codes was changes(Change 1004 as reserved, and add 1008, 1009, 1010).
Note
- Now spec allow to use WWW-Authenticate header and 401 status explicitly.
- Servers might redirect the client using a 3xx status code, but client are not required to follow them.
- Clients' reconnection on abnormal closure must be delayed (between 0 and 5 seconds is a reasonable initial delay, and subsequent reconnection should be delayed longer by exponential backoff.
HyBi 12
Change
Note
- Only editorial changes
- Sec-WebSocket-Version value is still 8.
HyBi 11
Change
Semantic changes
- Sec-WebSocket-Origin -> Origin
- Servers send all supported protocol numbers in Sec-WebSocket-Version header.
Note
- Sec-WebSocket-Version value is still 8, and 9/10/11 were reserved but were not and will not be used.
HyBi 10
Change
Semantic changes
- Status code 1007.
- Receiving strings including invalid UTF-8 result in Fail.
Note
- Sec-WebSocket-Version value is still 8.
HyBi 09
Change
Semantic changes
- On receiving a frame with any of RSV1-3 raised but no extension negotiated, Fail the WebSocket Connection.
- It seems that unknown opcode will also result in Fail in HyBi 10. (TBD)
Note
- Sec-WebSocket-Version value is still 8.
HyBi 08
Semantic changes
- Absolute path is now allowed for resource.
- extension parameter is token.
- Sec-WebSocket-Protocol from server to client is token.
- Status code 1005 and 1006 are added, and all codes are unsigned.
- Internal error results in 1006.
- HTTP fallback status codes are clarified.
HyBi 07
HyBi 06
Major changes
- "Connection" header must INCLUDE "Upgrade", rather than is equal to "Upgrade"
HyBi 05
Change
Major changes
- Removed Sec-WebSocket-Nonce
- Changed masking : SHA-1, client nonce, server nonce, CSPRNG -> CSPRNG only
- Specified the body of close frame explicitly
- ABNF fix for origin and protocol
- Added detailed Sec-WebSocket-Extensions format specification
Typos, remanet removal
- Removed all occurrence of Sec-WebSocket-Location
- Added IANA Sec-WebSocket-Accept section
Trivial changes
- The value of Sec-WebSocket-Version is now 5
HyBi 04
Change
Major changes
- Added frame masking
- Changed opening handshake
- Sec-WebSocket-Key1, Sec-WebSocket-Key2, key3, response -> Sec-WebSocket-Key, Sec-WebSocket-Nonce, Sec-WebSocket-Accept)
- Added Sec-WebSocket-Extensions for extension negotiation
- Upgrade header is now case-insensitive (HTTP compliant)
- Flipped MORE bit and renamed it to FIN bit
Tiny changes
- Renamed Sec-WebSocket-Draft to Sec-WebSocket-Version
- Renamed Origin to Sec-WebSocket-Origin
- Added ABNF (one used in HTTP RFC2616) clarification to Sec-WebSocket-Protocol
- Changed subprotocols separator from SP to ','
- Removed Sec-WebSocket-Location
Library dependency
Introduced
Eliminated
HyBi 03
Change
- Added one known extension "compression"
- Added close frame body matching step to closing handshake
- To distinguish close frames among virtual channels in multiplexed connection
Library dependency
Introduced
Note
- The value of Sec-WebSocket-Draft is still 2
HyBi 02
Change
- Added /defer cookies/ flag
- Added Sec-WebSocket-Draft with a value of 2
HyBi 01
Change
- Changed frame format
- Added extension mechanism (no negotiation yet)
Hixie 76 (HyBi 00)
Change
- Added challenge/response handshaking using binary data
- Added closing handshake
Library dependency
Introduced
Hixie 75
Extension spec drafts
Compression
ietf 00
websocket-perframe-deflate-06
websocket-perframe-deflate-05
websocket-perframe-deflate-04
websocket-perframe-deflate-03
websocket-perframe-deflate-02
websocket-perframe-deflate-01
websocket-perframe-deflate-00
A Multiplexing Extension for WebSockets
ietf 01
ietf 00
google-mux-03
google-mux-02
google-mux-01
google-mux-00
Rationale
Contents placed here has been merged into FAQ on the IETF HyBi WG site.
Other proposals
References/Tools
