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ART HTTP extended connect 42 The mechanism for running the WebSocket Protocol over a single stream of an HTTP/2 connection is equally applicable to HTTP/3, but the HTTP-version-specific details need to be specified. This document describes how the mechanism is adapted for HTTP/3.

Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at .

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Table of Contents

• .  Introduction
• .  Conventions and Definitions
• .  WebSockets Upgrade over HTTP/3
• .  Security Considerations
• .  IANA Considerations
• .  Normative References
• Acknowledgments
• Author's Address

Introduction "" defines an extension to HTTP/2 that is also useful in HTTP/3 . This extension makes use of an HTTP/2 setting. gives some guidance on what changes (if any) are appropriate when porting settings from HTTP/2 to HTTP/3.

Conventions and Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

WebSockets Upgrade over HTTP/3 defines a mechanism for running the WebSocket Protocol over a single stream of an HTTP/2 connection. It defines an Extended CONNECT method that specifies a new ":protocol" pseudo-header field and new semantics for the ":path" and ":authority" pseudo-header fields. It also defines a new HTTP/2 setting sent by a server to allow the client to use Extended CONNECT. The semantics of the pseudo-header fields and setting are identical to those in HTTP/2 as defined in . requires that HTTP/3 settings be registered separately for HTTP/3. The SETTINGS_ENABLE_CONNECT_PROTOCOL value is 0x08 (decimal 8), as in HTTP/2. If a server advertises support for Extended CONNECT but receives an Extended CONNECT request with a ":protocol" value that is unknown or is not supported, the server SHOULD respond to the request with a 501 (Not Implemented) status code (). A server MAY provide more information via a "problem details" response . The HTTP/3 stream closure is also analogous to the TCP connection closure of . Orderly TCP-level closures are represented as a FIN bit on the stream (). RST exceptions are represented with a stream error () of type H3_REQUEST_CANCELLED ().

Security Considerations This document introduces no new security considerations beyond those discussed in .

IANA Considerations This document registers a new setting in the "HTTP/3 Settings" registry ().

Value:

0x08

Setting Name:

SETTINGS_ENABLE_CONNECT_PROTOCOL

Default:

0

Status:

permanent

Specification:

This document

Change Controller:

IETF

Contact:

HTTP Working Group (ietf-http-wg@w3.org)

Normative References In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. The WebSocket Protocol enables two-way communication between a client running untrusted code in a controlled environment to a remote host that has opted-in to communications from that code. The security model used for this is the origin-based security model commonly used by web browsers. The protocol consists of an opening handshake followed by basic message framing, layered over TCP. The goal of this technology is to provide a mechanism for browser-based applications that need two-way communication with servers that does not rely on opening multiple HTTP connections (e.g., using XMLHttpRequest or <iframe>s and long polling). [STANDARDS-TRACK] This document defines a "problem detail" as a way to carry machine- readable details of errors in a HTTP response to avoid the need to define new error response formats for HTTP APIs. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. This document defines a mechanism for running the WebSocket Protocol (RFC 6455) over a single stream of an HTTP/2 connection.

Acknowledgments This document had reviews and input from many contributors in the IETF HTTP and QUIC Working Groups, with substantive input from , , , , , , and .

Author's Address Google

rch@google.com