draft-reschke-http-jfv-06.txt		draft-reschke-http-jfv-07.txt
	Network Working Group J. Reschke		Network Working Group J. Reschke
	Internet-Draft greenbytes		Internet-Draft greenbytes
	Intended status: Standards Track June 25, 2017		Intended status: Standards Track October 24, 2017
	Expires: December 27, 2017		Expires: April 27, 2018
	A JSON Encoding for HTTP Header Field Values		A JSON Encoding for HTTP Header Field Values
	draft-reschke-http-jfv-06		draft-reschke-http-jfv-07
	Abstract		Abstract
	This document establishes a convention for use of JSON-encoded field		This document establishes a convention for use of JSON-encoded field
	values in HTTP header fields.		values in HTTP header fields.
	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 ietf-http-		the Hypertext Transfer Protocol (HTTP) mailing list at ietf-http-
	wg@w3.org [1], which may be joined by sending a message with subject		wg@w3.org [1], which may be joined by sending a message 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-jfv>.		<http://greenbytes.de/tech/webdav/#draft-reschke-http-jfv>.
	The changes in this draft are summarized in Appendix E.9.		The changes in this draft are summarized in Appendix E.10.
	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 December 27, 2017.		This Internet-Draft will expire on April 27, 2018.
	Copyright Notice		Copyright Notice
	Copyright (c) 2017 IETF Trust and the persons identified as the		Copyright (c) 2017 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 . . . . . . . . . . . . . . . . . . . . . . . . 3
	skipping to change at page 2, line 37 ¶		skipping to change at page 2, line 37 ¶
	6. Deployment Considerations . . . . . . . . . . . . . . . . . . 6		6. Deployment Considerations . . . . . . . . . . . . . . . . . . 6
	7. Interoperability Considerations . . . . . . . . . . . . . . . 6		7. Interoperability Considerations . . . . . . . . . . . . . . . 6
	7.1. Encoding and Characters . . . . . . . . . . . . . . . . . 6		7.1. Encoding and Characters . . . . . . . . . . . . . . . . . 6
	7.2. Numbers . . . . . . . . . . . . . . . . . . . . . . . . . 6		7.2. Numbers . . . . . . . . . . . . . . . . . . . . . . . . . 6
	7.3. Object Constraints . . . . . . . . . . . . . . . . . . . 7		7.3. Object Constraints . . . . . . . . . . . . . . . . . . . 7
	8. Internationalization Considerations . . . . . . . . . . . . . 7		8. Internationalization Considerations . . . . . . . . . . . . . 7
	9. Security Considerations . . . . . . . . . . . . . . . . . . . 7		9. Security Considerations . . . . . . . . . . . . . . . . . . . 7
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7		10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
	10.1. Normative References . . . . . . . . . . . . . . . . . . 7		10.1. Normative References . . . . . . . . . . . . . . . . . . 7
	10.2. Informative References . . . . . . . . . . . . . . . . . 8		10.2. Informative References . . . . . . . . . . . . . . . . . 8
			10.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 9
	Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 10		Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 10
	A.1. Content-Length . . . . . . . . . . . . . . . . . . . . . 10		A.1. Content-Length . . . . . . . . . . . . . . . . . . . . . 10
	A.2. Content-Disposition . . . . . . . . . . . . . . . . . . . 10		A.2. Content-Disposition . . . . . . . . . . . . . . . . . . . 10
	A.3. WWW-Authenticate . . . . . . . . . . . . . . . . . . . . 11		A.3. WWW-Authenticate . . . . . . . . . . . . . . . . . . . . 11
	A.4. Accept-Encoding . . . . . . . . . . . . . . . . . . . . . 12		A.4. Accept-Encoding . . . . . . . . . . . . . . . . . . . . . 12
	Appendix B. Use of JSON Field Value Encoding in the Wild . . . . 13		Appendix B. Use of JSON Field Value Encoding in the Wild . . . . 13
	B.1. W3C Reporting API Specification . . . . . . . . . . . . . 14		B.1. W3C Reporting API Specification . . . . . . . . . . . . . 14
	B.2. W3C Clear Site Data Specification . . . . . . . . . . . . 14		B.2. W3C Clear Site Data Specification . . . . . . . . . . . . 14
	B.3. W3C Feature Policy Specification . . . . . . . . . . . . 14		B.3. W3C Feature Policy Specification . . . . . . . . . . . . 14
	Appendix C. Relation to HTTP 'Key' Header Field . . . . . . . . 14		Appendix C. Relation to HTTP 'Key' Header Field . . . . . . . . 14
	Appendix D. Discussion . . . . . . . . . . . . . . . . . . . . . 14		Appendix D. Discussion . . . . . . . . . . . . . . . . . . . . . 14
	Appendix E. Change Log (to be removed by RFC Editor before		Appendix E. Change Log (to be removed by RFC Editor before
	publication) . . . . . . . . . . . . . . . . . . . . 14		publication) . . . . . . . . . . . . . . . . . . . . 15
	E.1. Since draft-reschke-http-jfv-00 . . . . . . . . . . . . . 15		E.1. Since draft-reschke-http-jfv-00 . . . . . . . . . . . . . 15
	E.2. Since draft-reschke-http-jfv-01 . . . . . . . . . . . . . 15		E.2. Since draft-reschke-http-jfv-01 . . . . . . . . . . . . . 15
	E.3. Since draft-reschke-http-jfv-02 . . . . . . . . . . . . . 15		E.3. Since draft-reschke-http-jfv-02 . . . . . . . . . . . . . 15
	E.4. Since draft-reschke-http-jfv-03 . . . . . . . . . . . . . 15		E.4. Since draft-reschke-http-jfv-03 . . . . . . . . . . . . . 15
	E.5. Since draft-reschke-http-jfv-04 . . . . . . . . . . . . . 15		E.5. Since draft-reschke-http-jfv-04 . . . . . . . . . . . . . 15
	E.6. Since draft-ietf-httpbis-jfv-00 . . . . . . . . . . . . . 15		E.6. Since draft-ietf-httpbis-jfv-00 . . . . . . . . . . . . . 15
	E.7. Since draft-ietf-httpbis-jfv-01 . . . . . . . . . . . . . 15		E.7. Since draft-ietf-httpbis-jfv-01 . . . . . . . . . . . . . 15
	E.8. Since draft-ietf-httpbis-jfv-02 . . . . . . . . . . . . . 15		E.8. Since draft-ietf-httpbis-jfv-02 . . . . . . . . . . . . . 16
	E.9. Since draft-reschke-http-jfv-05 . . . . . . . . . . . . . 16		E.9. Since draft-reschke-http-jfv-05 . . . . . . . . . . . . . 16
			E.10. Since draft-reschke-http-jfv-06 . . . . . . . . . . . . . 16
	Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 16		Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 16
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 16		Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 16
	1. Introduction		1. Introduction
	Defining syntax for new HTTP header fields ([RFC7230], Section 3.2)		Defining syntax for new HTTP header fields ([RFC7230], Section 3.2)
	is non-trivial. Among the commonly encountered problems are:		is non-trivial. Among the commonly encountered problems are:
	o There is no common syntax for complex field values. Several well-		o There is no common syntax for complex field values. Several well-
	known header fields do use a similarly looking syntax, but it is		known header fields do use a similarly looking syntax, but it is
	skipping to change at page 7, line 51 ¶		skipping to change at page 7, line 51 ¶
	smuggle information through field values; however, this concern is		smuggle information through field values; however, this concern is
	shared with other widely used formats, such as those using parameters		shared with other widely used formats, such as those using parameters
	in the form of name/value pairs.		in the form of name/value pairs.
	10. References		10. References
	10.1. Normative References		10.1. Normative References
	[RFC0020] Cerf, V., "ASCII format for network interchange", STD 80,		[RFC0020] Cerf, V., "ASCII format for network interchange", STD 80,
	RFC 20, DOI 10.17487/RFC0020, October 1969,		RFC 20, DOI 10.17487/RFC0020, October 1969,
	<http://www.rfc-editor.org/info/rfc20>.		<https://www.rfc-editor.org/info/rfc20>.
	[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax		[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
	Specifications: ABNF", STD 68, RFC 5234,		Specifications: ABNF", STD 68, RFC 5234,
	DOI 10.17487/RFC5234, January 2008,		DOI 10.17487/RFC5234, January 2008,
	<http://www.rfc-editor.org/info/rfc5234>.		<https://www.rfc-editor.org/info/rfc5234>.
	[RFC7159] Bray, T., "The JavaScript Object Notation (JSON) Data		[RFC7159] Bray, T., "The JavaScript Object Notation (JSON) Data
	Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March		Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
	2014, <http://www.rfc-editor.org/info/rfc7159>.		2014, <https://www.rfc-editor.org/info/rfc7159>.
	[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, DOI 10.17487/RFC7230, 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,
	DOI 10.17487/RFC7231, June 2014,		DOI 10.17487/RFC7231, June 2014,
	<http://www.rfc-editor.org/info/rfc7231>.		<https://www.rfc-editor.org/info/rfc7231>.
	[RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493,		[RFC7493] Bray, T., Ed., "The I-JSON Message Format", RFC 7493,
	DOI 10.17487/RFC7493, March 2015,		DOI 10.17487/RFC7493, March 2015,
	<http://www.rfc-editor.org/info/rfc7493>.		<https://www.rfc-editor.org/info/rfc7493>.
	10.2. Informative References		10.2. Informative References
	[CLEARSITE]		[CLEARSITE]
	West, M., "Clear Site Data", W3C Working Draft WD-clear-		West, M., "Clear Site Data", W3C Working Draft WD-clear-
	site-data-20160720, July 2016,		site-data-20160720, July 2016,
	<http://www.w3.org/TR/2016/WD-clear-site-data-20160720/>.		<http://www.w3.org/TR/2016/WD-clear-site-data-20160720/>.
	Latest version available at <http://www.w3.org/TR/clear-		Latest version available at <http://www.w3.org/TR/clear-
	site-data/>.		site-data/>.
	[ECMA-262]		[ECMA-262]
	Ecma International, "ECMA-262 6th Edition, The ECMAScript		Ecma International, "ECMA-262 6th Edition, The ECMAScript
	2015 Language Specification", Standard ECMA-262, June		2015 Language Specification", Standard ECMA-262, June
	2015, <http://www.ecma-international.org/ecma-262/6.0/>.		2015, <http://www.ecma-international.org/ecma-262/6.0/>.
	[FEATUREPOL]		[FEATUREPOL]
	Clelland, I., "Clear Site Data", W3C Draft Community Group		Clelland, I., "Clear Site Data", W3C Draft Community Group
	Report , June 2017, <https://wicg.github.io/feature-		Report , June 2017,
	policy/>.		<https://wicg.github.io/feature-policy/>.
	[HSTRUCT] Kamp, P-H., "HTTP Header Common Structure", draft-ietf-		[HSTRUCT] Kamp, P-H., "HTTP Header Common Structure", draft-ietf-
	httpbis-header-structure-01 (work in progress), April		httpbis-header-structure-01 (work in progress), April
	2017.		2017.
	[ISO-8859-1]		[ISO-8859-1]
	International Organization for Standardization,		International Organization for Standardization,
	"Information technology -- 8-bit single-byte coded graphic		"Information technology -- 8-bit single-byte coded graphic
	character sets -- Part 1: Latin alphabet No. 1", ISO/		character sets -- Part 1: Latin alphabet No. 1", ISO/
	IEC 8859-1:1998, 1998.		IEC 8859-1:1998, 1998.
	skipping to change at page 9, line 23 ¶		skipping to change at page 9, line 23 ¶
	progress), March 2016.		progress), March 2016.
	[REPORTING]		[REPORTING]
	Grigorik, I. and M. West, "Reporting API 1", W3C Group		Grigorik, I. and M. West, "Reporting API 1", W3C Group
	Note NOTE-reporting-1-20160607, June 2016,		Note NOTE-reporting-1-20160607, June 2016,
	<http://www.w3.org/TR/2016/NOTE-reporting-1-20160607/>.		<http://www.w3.org/TR/2016/NOTE-reporting-1-20160607/>.
	Latest version available at <http://www.w3.org/TR/		Latest version available at <http://www.w3.org/TR/
	reporting-1/>.		reporting-1/>.
	[RFC5987] Reschke, J., "Character Set and Language Encoding for
	Hypertext Transfer Protocol (HTTP) Header Field
	Parameters", RFC 5987, DOI 10.17487/RFC5987, August 2010,
	<http://www.rfc-editor.org/info/rfc5987>.
	[RFC6266] Reschke, J., "Use of the Content-Disposition Header Field		[RFC6266] Reschke, J., "Use of the Content-Disposition Header Field
	in the Hypertext Transfer Protocol (HTTP)", RFC 6266,		in the Hypertext Transfer Protocol (HTTP)", RFC 6266,
	DOI 10.17487/RFC6266, June 2011,		DOI 10.17487/RFC6266, June 2011,
	<http://www.rfc-editor.org/info/rfc6266>.		<https://www.rfc-editor.org/info/rfc6266>.
	[RFC6365] Hoffman, P. and J. Klensin, "Terminology Used in		[RFC6365] Hoffman, P. and J. Klensin, "Terminology Used in
	Internationalization in the IETF", BCP 166, RFC 6365,		Internationalization in the IETF", BCP 166, RFC 6365,
	DOI 10.17487/RFC6365, September 2011,		DOI 10.17487/RFC6365, September 2011,
	<http://www.rfc-editor.org/info/rfc6365>.		<https://www.rfc-editor.org/info/rfc6365>.
	[RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer		[RFC7235] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
	Protocol (HTTP/1.1): Authentication", RFC 7235,		Protocol (HTTP/1.1): Authentication", RFC 7235,
	DOI 10.17487/RFC7235, June 2014,		DOI 10.17487/RFC7235, June 2014,
	<http://www.rfc-editor.org/info/rfc7235>.		<https://www.rfc-editor.org/info/rfc7235>.
			[RFC8187] Reschke, J., "Indicating Character Encoding and Language
			for HTTP Header Field Parameters", RFC 8187,
			DOI 10.17487/RFC8187, September 2017,
			<https://www.rfc-editor.org/info/rfc8187>.
	[XMLHttpRequest]		[XMLHttpRequest]
	WhatWG, "XMLHttpRequest", <https://xhr.spec.whatwg.org/>.		WhatWG, "XMLHttpRequest", <https://xhr.spec.whatwg.org/>.
			10.3. URIs
			[1] mailto:ietf-http-wg@w3.org
			[2] mailto:ietf-http-wg-request@w3.org?subject=subscribe
	Appendix A. Examples		Appendix A. Examples
	This section shows how some of the existing HTTP header fields would		This section shows how some of the existing HTTP header fields would
	look like if they would use the format defined by this specification.		look like if they would use the format defined by this specification.
	A.1. Content-Length		A.1. Content-Length
	"Content-Length" is defined in Section 3.3.2 of [RFC7230], with the		"Content-Length" is defined in Section 3.3.2 of [RFC7230], with the
	field value's ABNF being:		field value's ABNF being:
	skipping to change at page 11, line 21 ¶		skipping to change at page 11, line 21 ¶
	which would translate to a header field value of:		which would translate to a header field value of:
	{ "Attachment": { "filename" : "example.html" } }		{ "Attachment": { "filename" : "example.html" } }
	The third example in Section 5 of [RFC6266] uses a filename parameter		The third example in Section 5 of [RFC6266] uses a filename parameter
	containing non-US-ASCII characters:		containing non-US-ASCII characters:
	attachment; filename*=UTF-8''%e2%82%ac%20rates		attachment; filename*=UTF-8''%e2%82%ac%20rates
	Note that in this case, the "filename*" parameter uses the encoding		Note that in this case, the "filename*" parameter uses the encoding
	defined in [RFC5987], representing a filename starting with the		defined in [RFC8187], representing a filename starting with the
	Unicode character U+20AC (EURO SIGN), followed by " rates". If the		Unicode character U+20AC (EURO SIGN), followed by " rates". If the
	definition of Content-Disposition would have used the format proposed		definition of Content-Disposition would have used the format proposed
	here, the workaround involving the "parameter*" syntax would not have		here, the workaround involving the "parameter*" syntax would not have
	been needed at all.		been needed at all.
	The JSON representation of this value could then be:		The JSON representation of this value could then be:
	{ "attachment": { "filename" : "\u20AC rates" } }		{ "attachment": { "filename" : "\u20AC rates" } }
	A.3. WWW-Authenticate		A.3. WWW-Authenticate
	skipping to change at page 14, line 13 ¶		skipping to change at page 14, line 13 ¶
	The sections below summarize the current usage of this format.		The sections below summarize the current usage of this format.
	B.1. W3C Reporting API Specification		B.1. W3C Reporting API Specification
	Defined in W3C Note "Reporting API 1" (Section 3.1 of [REPORTING]).		Defined in W3C Note "Reporting API 1" (Section 3.1 of [REPORTING]).
	Still in use in latest editor copy as of June 2017.		Still in use in latest editor copy as of June 2017.
	B.2. W3C Clear Site Data Specification		B.2. W3C Clear Site Data Specification
	Defined in W3C Working Draft "Clear Site Data" (Section 2.1 of		Defined in W3C Working Draft "Clear Site Data" (Section 2.1 of
	[CLEARSITE]). Latest Editor's Draft replaces the use of JSON with a		[CLEARSITE]). Latest Editor's Draft at <https://w3c.github.io/
	custom syntax (see <https://lists.w3.org/Archives/Public/ietf-http-		webappsec-clear-site-data/#header> replaces the use of JSON with a
			custom syntax that happens to be somewhat compatible with an array of
			JSON strings (see <https://lists.w3.org/Archives/Public/ietf-http-
	wg/2017AprJun/0214.html> for feedback).		wg/2017AprJun/0214.html> for feedback).
	B.3. W3C Feature Policy Specification		B.3. W3C Feature Policy Specification
	Defined in W3C Draft Community Group Report "Feature Policy"		Defined in W3C Draft Community Group Report "Feature Policy"
	(Section 6.1 of [FEATUREPOL]). Previously relied on this document,		(Section 6.1 of [FEATUREPOL]). Previously relied on this document,
	now replicates the syntax into a custom ABNF defined in a separate		now replicates the syntax into a custom ABNF defined in a separate
	section (Section 5.1 of [FEATUREPOL]).		section (Section 5.1 of [FEATUREPOL]).
	Appendix C. Relation to HTTP 'Key' Header Field		Appendix C. Relation to HTTP 'Key' Header Field
	skipping to change at page 16, line 13 ¶		skipping to change at page 16, line 19 ¶
	Updated XHR reference.		Updated XHR reference.
	E.9. Since draft-reschke-http-jfv-05		E.9. Since draft-reschke-http-jfv-05
	Add meat to "Using this Format in Header Field Definitions".		Add meat to "Using this Format in Header Field Definitions".
	Add a few lines on the relation to "Key".		Add a few lines on the relation to "Key".
	Summarize current use of the format.		Summarize current use of the format.
			E.10. Since draft-reschke-http-jfv-06
			RFC 5987 is obsoleted by RFC 8187.
			Upcate CLEARSITE comment.
	Acknowledgements		Acknowledgements
	Thanks go to the Hypertext Transfer Protocol Working Group		Thanks go to the Hypertext Transfer Protocol Working Group
	participants.		participants.
	Author's Address		Author's Address
	Julian F. Reschke		Julian F. Reschke
	greenbytes GmbH		greenbytes GmbH
	Hafenweg 16		Hafenweg 16
End of changes. 25 change blocks.
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