Internet-Draft | SETTINGS_ENABLE_WEBSOCKETS | January 2023 |
Yamamoto | Expires 11 July 2023 | [Page] |
SETTINGS_ENABLE_WEBSOCKETS settings parameter for HTTP/2 and HTTP/3
Abstract
This document proposes a new HTTP settings parameter, SETTINGS_ENABLE_WEBSOCKETS. This parameter indicates whether the server supports bootstrapping WebSockets over the established connection.¶
Discussion Venues
This note is to be removed before publishing as an RFC.¶
Discussion of this document takes place on the HTTP Working Group mailing list (ietf-http-wg@w3.org), which is archived at https://lists.w3.org/Archives/Public/ietf-http-wg/.¶
Source for this draft and an issue tracker can be found at https://github.com/momoka0122y/draft-settings-enable-websockets.¶
Status of This Memo
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.¶
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.¶
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This Internet-Draft will expire on 11 July 2023.¶
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the document authors. All rights reserved.¶
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
1. Introduction
The mechanisms for running the WebSocket protocol [RFC6455] over a single stream of an HTTP/2 and HTTP/3 connection is defined in [RFC8441] and [RFC9220]. The extended CONNECT mechanism is used for bootstrapping WebSockets from HTTP/2 and HTTP/3. Support for the extended CONNECT mechanism is advertised using HTTP/2 and HTTP/3 settings parameter SETTINGS_ENABLE_CONNECT_PROTOCOL.¶
However, the support of extended CONNECT does not necessarily indicate support for WebSockets over that HTTP connection. Other protocols such as [WEBTRANSPORT] also use extended CONNECT and send SETTINGS_ENABLE_CONNECT_PROTOCOL settings parameters as well.¶
Suppose the server supports extended CONNECT but not bootstrapping WebSockets over that HTTP connection. In this case, the client sending a WebSocket handshake request will result in a response of 501 (Not Implemented) status code (Section 15.6.2 of [HTTP]), and the client would need to fall back to trying the WebSocket handshake over HTTP/1.¶
This is why a SETTINGS_ENABLE_WEBSOCKETS settings parameter is needed.¶
2. SETTINGS_ENABLE_WEBSOCKETS settigs parameter for H2 and H3
This document adds a new SETTINGS parameter to those defined by [HTTP/3] Section 11.2.2 and [HTTP/2] Section 11.3.¶
The new parameter name is SETTINGS_ENABLE_WEBSOCKETS. The value of the parameter MUST be 0 or 1, with 0 being the default.¶
A sender MUST NOT send a SETTINGS_ENABLE_WEBSOCKETS parameter with the value of 0 after previously sending a value of 1.¶
If the server supports bootstrapping WebSockets over the HTTP connection, it SHOULD include the SETTINGS_ENABLE_WEBSOCKETS parameter in the SETTINGS frame with a value of 1. If the server does not support bootstrapping WebSockets over the HTTP connection it SHOULD send the parameter with a value of 0.¶
A client MUST not send this setting parameter. Receipt of this parameter by a server does not have any impact.¶
The SETTINGS_ENABLE_WEBSOCKETS parameter would allow the client to determine in advance whether the server supports WebSockets over the connection for HTTP/2 or HTTP/3. This allows the client to avoid sending unnecessary WebSocket handshake requests on HTTP connections that do not support WebSockets.¶
This mechanism will improve compatibility with other extended CONNECT-based protocols.¶
For compatibility with past implementations which do not use this parameter, clients MAY initiate a WebSocket request without the receipt of this parameter.¶
3. Security Considerations
This document introduces no new security considerations beyond those discussed in [RFC8441].¶
4. IANA Considerations
4.1. HTTP3
This document registers a new entry in the "HTTP/3 Settings" registry (Section 11.2.2 of [HTTP/3]).¶
Value: TBD¶
Setting Name: SETTINGS_ENABLE_WEBSOCKETS¶
Default: 0¶
Status: permanent¶
Specification: This document¶
Change Controller: IETF¶
Contact: HTTP Working Group (ietf-http-wg@w3.org)¶
5. References
5.1. Normative References
- [HTTP]
- Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, Ed., "HTTP Semantics", RFC 9110, DOI 10.17487/RFC9110, , <https://www.rfc-editor.org/rfc/rfc9110>.
- [HTTP/2]
- Thomson, M., Ed. and C. Benfield, Ed., "HTTP/2", RFC 9113, DOI 10.17487/RFC9113, , <https://www.rfc-editor.org/rfc/rfc9113>.
- [HTTP/3]
- Bishop, M., Ed., "Hypertext Transfer Protocol Version 3 (HTTP/3)", RFC 9114, DOI 10.17487/RFC9114, , <https://www.rfc-editor.org/rfc/rfc9114>.
- [RFC6455]
- Fette, I. and A. Melnikov, "The WebSocket Protocol", RFC 6455, DOI 10.17487/RFC6455, , <https://www.rfc-editor.org/rfc/rfc6455>.
- [RFC8441]
- McManus, P., "Bootstrapping WebSockets with HTTP/2", RFC 8441, DOI 10.17487/RFC8441, , <https://www.rfc-editor.org/rfc/rfc8441>.
- [RFC9220]
- Hamilton, R., "Bootstrapping WebSockets with HTTP/3", RFC 9220, DOI 10.17487/RFC9220, , <https://www.rfc-editor.org/rfc/rfc9220>.
5.2. Informative References
- [WEBTRANSPORT]
- Vasiliev, V., "The WebTransport Protocol Framework", Work in Progress, Internet-Draft, draft-ietf-webtrans-overview-04, , <https://datatracker.ietf.org/doc/html/draft-ietf-webtrans-overview-04>.
Acknowledgments
TODO acknowledge people.¶
Thank you for reading this draft. :)¶