RFC 6455, "The WebSocket Protocol", December 2011Source of RFC: hybi (app)
Errata ID: 5498
Status: Held for Document Update
Publication Format(s) : TEXT
Reported By: Patrick McManus
Date Reported: 2018-09-14
Held for Document Update by: Alexey Melnikov
Date Held: 2018-09-20
Section 11.2 says:
Name of token WebSocket
It should say:
Name of token websocket
The HTTP bootstrap request is required to use an upgrade token of all lowercase "websocket" -
5. The request MUST contain an |Upgrade| header field whose value
MUST include the "websocket" keyword.
The registration is for "WebSocket" (capital W and capital S). In practice "websocket" is used.
Although the interpretation of that is defined case-insensitively for this RFC (which conflicts with general HTTP semantics where this is case sensitive). As part of RFC 8441, the IANA registry has been updated to also include "websocket" with a reference to both RFC 6455 and RFC 8441.
imo this errata should be held for update and the reference to "WebSocket" removed at that time.
See also https://www.rfc-editor.org/errata/eid5453