draft-reschke-http-cice-02.txt		draft-reschke-http-cice-latest.txt
	Network Working Group J. Reschke		Network Working Group J. Reschke
	Internet-Draft greenbytes		Internet-Draft greenbytes
	Intended status: Standards Track March 9, 2015		Intended status: Standards Track April 11, 2024
	Expires: September 10, 2015		Expires: October 13, 2024
	Hypertext Transfer Protocol (HTTP) Client-Initiated Content-Encoding		Hypertext Transfer Protocol (HTTP) Client-Initiated Content-Encoding
	draft-reschke-http-cice-02		draft-reschke-http-cice-latest
	Abstract		Abstract
	In HTTP, "Content Codings" allow for payload encodings such as for		In HTTP, "Content Codings" allow for payload encodings such as for
	compression or integrity checks. In particular, the "gzip" content		compression or integrity checks. In particular, the "gzip" content
	coding is widely used for payload data sent in response messages.		coding is widely used for payload data sent in response messages.
	Content Codings can be used in request messages as well, however		Content Codings can be used in request messages as well, however
	discoverability is not on par with response messages. This document		discoverability is not on par with response messages. This document
	extends the HTTP "Accept-Encoding" header field for use in responses.		extends the HTTP "Accept-Encoding" header field for use in responses.
	Editorial Note (To be removed by RFC Editor before publication)		Editorial Note (To be removed by RFC Editor before publication)
	Distribution of this document is unlimited. Although this is not a		Distribution of this document is unlimited. Although this is not a
	work item of the HTTPbis Working Group, comments should be sent to		work item of the HTTPbis Working Group, comments should be sent to
	the Hypertext Transfer Protocol (HTTP) mailing list at		the Hypertext Transfer Protocol (HTTP) mailing list at ietf-http-
	ietf-http-wg@w3.org [1], which may be joined by sending a message		wg@w3.org [1], which may be joined by sending a message with subject
	with subject "subscribe" to ietf-http-wg-request@w3.org [2].		"subscribe" to ietf-http-wg-request@w3.org [2].
	Discussions of the HTTPbis Working Group are archived at		Discussions of the HTTPbis Working Group are archived at
	<http://lists.w3.org/Archives/Public/ietf-http-wg/>.		<http://lists.w3.org/Archives/Public/ietf-http-wg/>.
	XML versions and latest edits for this document are available from		XML versions and latest edits for this document are available from
	<http://greenbytes.de/tech/webdav/#draft-reschke-http-cice>.		<http://greenbytes.de/tech/webdav/#draft-reschke-http-cice>.
	The changes in this draft are summarized in Appendix A.2.		The changes in this draft are summarized in Appendix A.3.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on September 10, 2015.		This Internet-Draft will expire on October 13, 2024.
	Copyright Notice		Copyright Notice
	Copyright (c) 2015 IETF Trust and the persons identified as the		Copyright (c) 2024 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3		2. Notational Conventions . . . . . . . . . . . . . . . . . . . 3
	3. Extensions to 'Accept-Encoding' Header Field . . . . . . . . . 3		3. Extensions to 'Accept-Encoding' Header Field . . . . . . . . 3
	4. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4		4. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
	5. Deployment Considerations . . . . . . . . . . . . . . . . . . . 5		5. Deployment Considerations . . . . . . . . . . . . . . . . . . 4
	6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5		6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
	7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5		7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
	8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5		8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6		9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
	9.1. Normative References . . . . . . . . . . . . . . . . . . . 6		9.1. Normative References . . . . . . . . . . . . . . . . . . 5
	9.2. Informative References . . . . . . . . . . . . . . . . . . 6		9.2. Informative References . . . . . . . . . . . . . . . . . 6
			9.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 6
	Appendix A. Change Log (to be removed by RFC Editor before		Appendix A. Change Log (to be removed by RFC Editor before
	publication) . . . . . . . . . . . . . . . . . . . . . 6		publication) . . . . . . . . . . . . . . . . . . . . 7
	A.1. draft-reschke-http-cice-00 . . . . . . . . . . . . . . . . 6		A.1. draft-reschke-http-cice-00 . . . . . . . . . . . . . . . 7
	A.2. draft-reschke-http-cice-01 . . . . . . . . . . . . . . . . 6		A.2. draft-reschke-http-cice-01 . . . . . . . . . . . . . . . 7
			A.3. draft-reschke-http-cice-02 . . . . . . . . . . . . . . . 7
			Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
	1. Introduction		1. Introduction
	In HTTP, "Content Codings" allow for payload encodings such as for		In HTTP, "Content Codings" allow for payload encodings such as for
	compression or integrity checks ([RFC7231], Section 3.1.2). In		compression or integrity checks ([RFC7231], Section 3.1.2). In
	particular, the "gzip" content coding is widely used for payload data		particular, the "gzip" content coding is widely used for payload data
	sent in response messages.		sent in response messages.
	Content Codings can be used in request messages as well, however		Content Codings can be used in request messages as well, however
	discoverability is not on par with response messages. This document		discoverability is not on par with response messages. This document
	extends the HTTP "Accept-Encoding" header field ([RFC7231], Section		extends the HTTP "Accept-Encoding" header field ([RFC7231],
	5.3.4) for use in responses.		Section 5.3.4) for use in responses.
	2. Notational Conventions		2. Notational Conventions
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in [RFC2119].		document are to be interpreted as described in [RFC2119].
	This document reuses terminology used in the base HTTP		This document reuses terminology used in the base HTTP
	specifications, namely Section 2 of [RFC7230] and Section 3.1.2 of		specifications, namely Section 2 of [RFC7230] and Section 3.1.2 of
	[RFC7231].		[RFC7231].
	skipping to change at page 4, line 10 ¶		skipping to change at page 4, line 4 ¶
	Encoding" header field in that response, allowing clients to		Encoding" header field in that response, allowing clients to
	distinguish between content coding related issues and media type		distinguish between content coding related issues and media type
	related issues. In order to avoid confusion with media type related		related issues. In order to avoid confusion with media type related
	problems, servers that fail a request with a 415 status for reasons		problems, servers that fail a request with a 415 status for reasons
	unrelated to content codings SHOULD NOT include the "Accept-Encoding"		unrelated to content codings SHOULD NOT include the "Accept-Encoding"
	header field.		header field.
	While sending "Accept-Encoding" in a 415 (Unsupported Media Type)		While sending "Accept-Encoding" in a 415 (Unsupported Media Type)
	response will be the most common use case, it is not restricted to		response will be the most common use case, it is not restricted to
	this particular status code. For instance, a server might include it		this particular status code. For instance, a server might include it
	in a 2xx response when a request payload was big enough to justity		in a 2xx response when a request payload was big enough to justify
	use of a compression coding, but the client failed to do so.		use of a compression coding, but the client failed to do so.
	4. Example		4. Example
	Client submits a POST request using Content-Encoding "compress"		Client submits a POST request using Content-Encoding "compress"
	([RFC7231], Section 3.1.2.1):		([RFC7231], Section 3.1.2.1):
	POST /edit/ HTTP/1.1		POST /edit/ HTTP/1.1
	Host: example.org		Host: example.org
	Content-Type: application/atom+xml;type=entry		Content-Type: application/atom+xml;type=entry
	skipping to change at page 5, line 8 ¶		skipping to change at page 4, line 47 ¶
	Date: Fri, 09 May 2014 11:43:53 GMT		Date: Fri, 09 May 2014 11:43:53 GMT
	Accept-Encoding: identity		Accept-Encoding: identity
	Content-Length: 61		Content-Length: 61
	Content-Type: text/plain		Content-Type: text/plain
	This resource does not support content codings in requests.		This resource does not support content codings in requests.
	5. Deployment Considerations		5. Deployment Considerations
	Servers that do not support content codings in requests already are		Servers that do not support content codings in requests already are
	required to fail a request that does use a content coding. Section		required to fail a request that does use a content coding.
	6.5.13 of [RFC7231] recommends to use the status code 415		Section 6.5.13 of [RFC7231] recommends to use the status code 415
	(Unsupported Media Type), so the only change needed is to include the		(Unsupported Media Type), so the only change needed is to include the
	"Accept-Encoding" header field with value "identity" in that		"Accept-Encoding" header field with value "identity" in that
	response.		response.
	Servers that do support some content codings are required to fail		Servers that do support some content codings are required to fail
	requests with unsupported content codings as well. To be compliant		requests with unsupported content codings as well. To be compliant
	with this specification, servers will need to use the status code 415		with this specification, servers will need to use the status code 415
	(Unsupported Media Type) to signal the problem, and will have to		(Unsupported Media Type) to signal the problem, and will have to
	include an "Accept-Encoding" header field that enumerates the content		include an "Accept-Encoding" header field that enumerates the content
	codings that are supported. As the set of supported content codings		codings that are supported. As the set of supported content codings
	skipping to change at page 5, line 31 ¶		skipping to change at page 5, line 22 ¶
	trivial.		trivial.
	6. Security Considerations		6. Security Considerations
	This specification does not introduce any new security considerations		This specification does not introduce any new security considerations
	beyond those discussed in Section 9 of [RFC7231].		beyond those discussed in Section 9 of [RFC7231].
	7. IANA Considerations		7. IANA Considerations
	HTTP header fields are registered within the "Message Headers"		HTTP header fields are registered within the "Message Headers"
	registry located at		registry located at <http://www.iana.org/assignments/message-
	<http://www.iana.org/assignments/message-headers>, as defined by		headers>, as defined by [BCP90].
	[BCP90].
	This document updates the definition of the "Accept-Encoding" header		This document updates the definition of the "Accept-Encoding" header
	field, so the "Permanent Message Header Field Names" registry shall		field, so the "Permanent Message Header Field Names" registry shall
	be updated accordingly:		be updated accordingly:
	+-----------------+----------+----------+---------------------------+		+-----------------+----------+----------+---------------------------+
	| Header Field | Protocol | Status | Reference |		| Header Field | Protocol | Status | Reference |
	| Name | | | |		| Name | | | |
	+-----------------+----------+----------+---------------------------+		+-----------------+----------+----------+---------------------------+
	| Accept-Encoding | http | standard | [RFC7231], Section 5.3.4, |		| Accept-Encoding | http | standard | [RFC7231], Section 5.3.4, |
	| | | | extended by Section 3 of |		| | | | extended by Section 3 of |
	| | | | this document |		| | | | this document |
	+-----------------+----------+----------+---------------------------+		+-----------------+----------+----------+---------------------------+
	8. Acknowledgements		8. Acknowledgements
	Thanks go to the members of the and HTTPbis Working Group, namely		Thanks go to the members of the and HTTPbis Working Group, namely
	Amos Jeffries, Mark Nottingham, and Ted Hardie.		Amos Jeffries, Mark Nottingham, and Ted Hardie.
	9. References		9. References
	9.1. Normative References		9.1. Normative References
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997,		Requirement Levels", BCP 14, RFC 2119,
	<http://www.rfc-editor.org/info/rfc2119>.		DOI 10.17487/RFC2119, March 1997,
			<https://www.rfc-editor.org/info/rfc2119>.
	[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer		[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
	Protocol (HTTP/1.1): Message Syntax and Routing",		Protocol (HTTP/1.1): Message Syntax and Routing",
	RFC 7230, June 2014,		RFC 7230, DOI 10.17487/RFC7230, June 2014,
	<http://www.rfc-editor.org/info/rfc7230>.		<https://www.rfc-editor.org/info/rfc7230>.
	[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer		[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
	Protocol (HTTP/1.1): Semantics and Content", RFC 7231,		Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
	June 2014, <http://www.rfc-editor.org/info/rfc7231>.		DOI 10.17487/RFC7231, June 2014,
			<https://www.rfc-editor.org/info/rfc7231>.
	9.2. Informative References		9.2. Informative References
	[BCP90] Klyne, G., Nottingham, M., and J. Mogul, "Registration		[BCP90] Klyne, G., Nottingham, M., and J. Mogul, "Registration
	Procedures for Message Header Fields", BCP 90, RFC 3864,		Procedures for Message Header Fields", BCP 90, RFC 3864,
	September 2004, <http://www.rfc-editor.org/info/bcp90>.		September 2004, <https://www.rfc-editor.org/info/bcp90>.
	URIs		9.3. URIs
	[1] <mailto:ietf-http-wg@w3.org>		[1] mailto:ietf-http-wg@w3.org
	[2] <mailto:ietf-http-wg-request@w3.org?subject=subscribe>		[2] mailto:ietf-http-wg-request@w3.org?subject=subscribe
	Appendix A. Change Log (to be removed by RFC Editor before publication)		Appendix A. Change Log (to be removed by RFC Editor before publication)
	A.1. draft-reschke-http-cice-00		A.1. draft-reschke-http-cice-00
	Clarified that the information returned in Accept-Encoding is per		Clarified that the information returned in Accept-Encoding is per
	resource, not per server.		resource, not per server.
	Added some deployment considerations.		Added some deployment considerations.
	skipping to change at page 7, line 6 ¶		skipping to change at page 7, line 26 ¶
	A.2. draft-reschke-http-cice-01		A.2. draft-reschke-http-cice-01
	Restrict the scope of A-E from "future requests" to "at the time of		Restrict the scope of A-E from "future requests" to "at the time of
	this request".		this request".
	Mention use of A-E in responses other than 415.		Mention use of A-E in responses other than 415.
	Recommend not to include A-E in a 415 response unless there was		Recommend not to include A-E in a 415 response unless there was
	actually a problem related to content coding.		actually a problem related to content coding.
			A.3. draft-reschke-http-cice-02
			None yet.
	Author's Address		Author's Address
	Julian F. Reschke		Julian F. Reschke
	greenbytes GmbH		greenbytes GmbH
	Hafenweg 16		Hafenweg 16
	Muenster, NW 48155		Muenster, NW 48155
	Germany		Germany
	EMail: julian.reschke@greenbytes.de		EMail: julian.reschke@greenbytes.de
	URI: http://greenbytes.de/tech/webdav/		URI: http://greenbytes.de/tech/webdav/
End of changes. 23 change blocks.
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