Subject: [Errata Verified] RFC7230 (4667)

From: RFC Errata System <[email-masked]>
Date: Fri, 7 Oct 2016 13:30:52 -0700 (PDT)

The following errata report has been verified for RFC7230,
"Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing". 

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You may review the report below and at:
http://www.rfc-editor.org/errata_search.php?rfc=7230&eid=4667

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Status: Verified
Type: Technical

Reported by: Alex Rousskov <[email-masked]>
Date Reported: 2016-04-13
Verified by: Alexey Melnikov (IESG)

Section: 4.1.1

Original Text
-------------
chunk-ext      = *( ";" chunk-ext-name [ "=" chunk-ext-val ] )

Corrected Text
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chunk-ext      = *( BWS  ";" BWS chunk-ext-name
                    [ BWS  "=" BWS chunk-ext-val ] )

Notes
-----
The infamous "implicit *LWS" syntax rule in RFC 2616 allowed whitespace between
";" and chunk-ext-name in chunk-ext. Some HTTP agents generate that whitespace.
In my experience, HTTP agents that can parse chunk extensions usually can handle
that whitespace. Moreover, ICAP, which generally relies on HTTP/1 for its message
syntax, uses that whitespace when defining the "ieof" chunk extension in RFC 3507
Section 4.5:

\r\n
0; ieof\r\n\r\n

IMHO, RFC 7230 should either allow BWS before chunk-ext-name or at the very least
explicitly document the HTTP/1 syntax change and its effect on parsers used for both
ICAP and HTTP/1 messages (a very common case for ICAP-supporting HTTP
intermediaries and ICAP services).

I also recommend adding BWS around "=", for consistency and RFC 2616 backward
compatibility reasons. HTTPbis RFCs already do that for transfer-parameter and
auth-param that have similar syntax.

Please also consider adding BWS _before_ ";" for consistency and RFC 2616 backward
compatibility reasons. HTTPbis RFCs already do that for transfer-extension,
accept-ext, t-ranking, and other constructs with similar syntax.

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RFC7230 (draft-ietf-httpbis-p1-messaging-26)
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Title               : Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing
Publication Date    : June 2014
Author(s)           : R. Fielding, Ed., J. Reschke, Ed.
Category            : PROPOSED STANDARD
Source              : Hypertext Transfer Protocol Bis APP
Area                : Applications
Stream              : IETF
Verifying Party     : IESG