< draft-ietf-appsawg-json-pointer-02.txt		draft-ietf-appsawg-json-pointer-03.txt >
	Applications Area Working Group P. Bryan, Ed.		Applications Area Working Group P. Bryan, Ed.
	Internet-Draft ForgeRock		Internet-Draft ForgeRock
	Intended status: Informational K. Zyp		Intended status: Informational K. Zyp
	Expires: January 5, 2013 SitePen (USA)		Expires: February 12, 2013 SitePen (USA)
	M. Nottingham, Ed.		M. Nottingham, Ed.
	Rackspace		Rackspace
	July 4, 2012		August 11, 2012
	JSON Pointer		JSON Pointer
	draft-ietf-appsawg-json-pointer-02		draft-ietf-appsawg-json-pointer-03
	Abstract		Abstract
	JSON Pointer defines a string syntax for identifying a specific value		JSON Pointer defines a string syntax for identifying a specific value
	within a JSON document.		within a JSON document.
	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.
	skipping to change at page 1, line 34 ¶		skipping to change at page 1, line 34 ¶
	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 http://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 January 5, 2013.		This Internet-Draft will expire on February 12, 2013.
	Copyright Notice		Copyright Notice
	Copyright (c) 2012 IETF Trust and the persons identified as the		Copyright (c) 2012 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		(http://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
	skipping to change at page 2, line 13 ¶		skipping to change at page 2, line 13 ¶
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . 3		2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3		3. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
	4. Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . 3		4. Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . 3
	5. JSON String Representation . . . . . . . . . . . . . . . . . . 4		5. JSON String Representation . . . . . . . . . . . . . . . . . . 4
	6. URI Fragment Identifier Representation . . . . . . . . . . . . 5		6. URI Fragment Identifier Representation . . . . . . . . . . . . 5
	7. Error Handling . . . . . . . . . . . . . . . . . . . . . . . . 5		7. Error Handling . . . . . . . . . . . . . . . . . . . . . . . . 6
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
	9. Security Considerations . . . . . . . . . . . . . . . . . . . . 6		9. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
	10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6		10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
	11. Normative References . . . . . . . . . . . . . . . . . . . . . 6		11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
			11.1. Normative References . . . . . . . . . . . . . . . . . . . 7
			11.2. Informative References . . . . . . . . . . . . . . . . . . 7
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
	1. Introduction		1. Introduction
	This specification defines JSON Pointer, a string syntax for		This specification defines JSON Pointer, a string syntax for
	identifying a specific value within a JavaScript Object Notation		identifying a specific value within a JavaScript Object Notation
	(JSON) [RFC4627] document. It is intended to be easily expressed in		(JSON) [RFC4627] document. It is intended to be easily expressed in
	JSON string values and Uniform Resource Identifier (URI) [RFC3986]		JSON string values as well as Uniform Resource Identifier (URI)
	fragment identifiers.		[RFC3986] fragment identifiers.
	2. Conventions		2. 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 specification expresses normative syntax rules using Augmented		This specification expresses normative syntax rules using Augmented
	Backus-Naur Form [RFC5234] (ABNF) notation.		Backus-Naur Form [RFC5234] (ABNF) notation.
	3. Syntax		3. Syntax
	A JSON Pointer is a [Unicode] string containing a sequence of zero or		A JSON Pointer is a [Unicode] string containing a sequence of zero or
	more reference tokens, each prefixed by a '/' (%x2F) character.		more reference tokens, each prefixed by a '/' (%x2F) character.
	If a reference token contains '~' (%x7E) or '/' (%x2F) characters,		If a reference token contains '~' (%x7E) or '/' (%x2F) characters,
	they MUST be encoded as '~0' and '~1' respectively.		they MUST be encoded as '~0' and '~1' respectively.
	ABNF syntax:		Its ABNF syntax is:
	json-pointer = *( "/" reference-token )		json-pointer = *( "/" reference-token )
	reference-token = *( unescaped / escaped )		reference-token = *( unescaped / escaped )
	unescaped = %x00-2E / %x30-7D / %x7F-10FFFF		unescaped = %x00-2E / %x30-7D / %x7F-10FFFF
	escaped = "~" ( "0" / "1" )		escaped = "~" ( "0" / "1" )
	It is an error condition if a JSON Pointer value does not conform to		It is an error condition if a JSON Pointer value does not conform to
	this syntax (see Section 7).		this syntax (see Section 7).
	4. Evaluation		4. Evaluation
	Evaluation of a JSON Pointer begins with a reference to the root		Evaluation of a JSON Pointer begins with a reference to the root
	value of a JSON text document and completes with a reference to some		value of a JSON document and completes with a reference to some value
	value within the document. Each reference token in the JSON Pointer		within the document. Each reference token in the JSON Pointer is
	is sequentially evaluated.		sequentially evaluated.
	Evaluation of each reference token begins by decoding any escaped		Evaluation of each reference token begins by decoding any escaped
	character sequence; this is performed by first transforming any		character sequence; this is performed by first transforming any
	occurrence of the sequence '~1' to '/', then transforming any		occurrence of the sequence '~1' to '/', then transforming any
	occurrence of the sequence '~0' to '~'.		occurrence of the sequence '~0' to '~'.
	The reference token then modifies which value is referenced according		The reference token then modifies which value is referenced according
	to the following scheme:		to the following scheme:
	If the currently referenced value is a JSON object, the new		If the currently referenced value is a JSON object, the new
	referenced value is the object member with the name (after		referenced value is the object member with the name (after
	unescaping any backslash escape sequences that can occur in a JSON		unescaping any backslash escape sequences that can occur in a JSON
	string) identified by the reference token. The member name is		string) identified by the reference token. The member name is
	equal to the token if it has the same number of Unicode characters		equal to the token if it has the same number of Unicode characters
	as token and their code points are position-wise equal. If a		as token and their code points are position-wise equal. If a
	referenced member name is not unique in an object, the member that		referenced member name is not unique in an object, the member that
	is referenced is undefined.		is referenced is undefined, and evaluation fails (see below).
	If the currently referenced value is a JSON array, the reference		If the currently referenced value is a JSON array, the reference
	token MUST contain characters that represent an unsigned base-10		token MUST contain characters that represent an unsigned base-10
	integer value (possibly with leading zeros), and the new		integer value (possibly with leading zeros), and the new
	referenced value is the array element with the zero-based index		referenced value is the array element with the zero-based index
	identified by the token.		identified by the token.
	If a reference token is being evaluated against a JSON document, the		If a reference token is being evaluated against a JSON document,
	implementation MAY evaluate each token against a concrete value, and		implementations will evaluate each token against the document's
	terminate evaluation with an error condition if a evaluation fails to		contents, and terminate evaluation with an error condition if it
	resolve a concrete value (see Section 7).		fails to resolve a concrete value for any of the JSON pointer's
			reference tokens. See Section 7 for details.
	5. JSON String Representation		5. JSON String Representation
	A JSON Pointer can be represented in a JSON string value. Per		A JSON Pointer can be represented in a JSON string value. Per
	[RFC4627], section 2.5, all instances of quotation mark '"' (%x22),		[RFC4627], section 2.5, all instances of quotation mark '"' (%x22),
	reverse solidus '\' (%x5C) and control (%x00-1F) characters MUST be		reverse solidus '\' (%x5C) and control (%x00-1F) characters MUST be
	escaped.		escaped.
	For example, given the JSON document		For example, given the JSON document
	{		{
	"foo": ["bar", "baz"],		"foo": ["bar", "baz"],
	"": 0		"": 0,
	"a/b": 1,		"a/b": 1,
	"c%d": 2,		"c%d": 2,
	"e^f": 3,		"e^f": 3,
	"g|h": 4,		"g|h": 4,
	"i\\j": 5,		"i\\j": 5,
	"k\"l": 6,		"k\"l": 6,
	" ": 7,		" ": 7,
	"m~n": 8		"m~n": 8
	}		}
	Then the following JSON strings evaluate to the accompanying values:		Then the following JSON strings evaluate to the accompanying values:
	"" // the whole document		"" // the whole document
	"/foo" ["bar", "baz"]		"/foo" ["bar", "baz"]
	"/foo/0" "bar"		"/foo/0" "bar"
	"/" 0		"/" 0
	"/a~1b" 1		"/a~1b" 1
	"/c%d" 2		"/c%d" 2
	"/e^f" 3		"/e^f" 3
	"/g|h" 4		"/g|h" 4
	"/i\\j" 5		"/i\\j" 5
	"/k\"l" 6		"/k\"l" 6
	" " 7		"/ " 7
	"m~0n" 8		"/m~0n" 8
	6. URI Fragment Identifier Representation		6. URI Fragment Identifier Representation
	A JSON Pointer can be represented in a URI fragment identifier. by		A JSON Pointer can be represented in a URI fragment identifier. by
	encoding it into octets, using UTF-8 [RFC3629], percent-encoding		encoding it into octets, using UTF-8 [RFC3629], percent-encoding
	those characters not allowed by the fragment rule in [RFC3986].		those characters not allowed by the fragment rule in [RFC3986].
			Note that a given media type needs to nominate JSON Pointer as its
			fragment identifier syntax explicitly (usually, in its registration
			[RFC4288]); i.e., just because a document is JSON does not imply that
			JSON Pointer can be used as its fragment identifier syntax.
	Given the same example document as above, the following URI fragment		Given the same example document as above, the following URI fragment
	identifiers evaluate to the accompanying values:		identifiers evaluate to the accompanying values:
	# // the whole document		# // the whole document
	#/foo ["bar", "baz"]		#/foo ["bar", "baz"]
	#/foo/0 "bar"		#/foo/0 "bar"
	#/ 0		#/ 0
	#/a~1b 1		#/a~1b 1
	#/c%25d 2		#/c%25d 2
	#/e%5Ef 3		#/e%5Ef 3
	skipping to change at page 6, line 19 ¶		skipping to change at page 6, line 26 ¶
	This specification does not define how errors are handled; an		This specification does not define how errors are handled; an
	application of JSON Pointer SHOULD specify the impact and handling of		application of JSON Pointer SHOULD specify the impact and handling of
	each type of error.		each type of error.
	For example, some applications might stop pointer processing upon an		For example, some applications might stop pointer processing upon an
	error; others may attempt to recover from missing values by inserting		error; others may attempt to recover from missing values by inserting
	default ones.		default ones.
	8. IANA Considerations		8. IANA Considerations
	TBD		This document has no impact upon IANA.
	9. Security Considerations		9. Security Considerations
	A given JSON Pointer is not guaranteed to reference an actual JSON		A given JSON Pointer is not guaranteed to reference an actual JSON
	value. Implementations should be aware of this and take appropriate		value. Implementations should be aware of this and take appropriate
	precautions.		precautions.
	Note that JSON pointers can contain the NUL (Unicode U+0000)		Note that JSON pointers can contain the NUL (Unicode U+0000)
	character, which may not be representable in all programming		character, which may not be representable in all programming
	languages.		languages.
	10. Acknowledgements		10. Acknowledgements
	The following individuals contributed ideas, feedback and wording to		The following individuals contributed ideas, feedback and wording to
	this specification:		this specification:
	Mike Acar, Carsten Bormann, Tim Bray, Jacob Davies, Martin J.		Mike Acar, Carsten Bormann, Tim Bray, Jacob Davies, Martin J.
	Duerst, Bjoern Hoehrmann, James H. Manger, Drew Perttula, Julian		Duerst, Bjoern Hoehrmann, James H. Manger, Drew Perttula, Julian
	Reschke.		Reschke.
	11. Normative References		11. References
			11.1. 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, March 1997.
	[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO		[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
	10646", STD 63, RFC 3629, November 2003.		10646", STD 63, RFC 3629, November 2003.
	[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform		[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
	Resource Identifier (URI): Generic Syntax", STD 66,		Resource Identifier (URI): Generic Syntax", STD 66,
	RFC 3986, January 2005.		RFC 3986, January 2005.
	skipping to change at page 7, line 17 ¶		skipping to change at page 7, line 26 ¶
	[RFC4627] Crockford, D., "The application/json Media Type for		[RFC4627] Crockford, D., "The application/json Media Type for
	JavaScript Object Notation (JSON)", RFC 4627, July 2006.		JavaScript Object Notation (JSON)", RFC 4627, July 2006.
	[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax		[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
	Specifications: ABNF", STD 68, RFC 5234, January 2008.		Specifications: ABNF", STD 68, RFC 5234, January 2008.
	[Unicode] The Unicode Consortium, "The Unicode Standard, Version		[Unicode] The Unicode Consortium, "The Unicode Standard, Version
	6.0", October 2011,		6.0", October 2011,
	<http://www.unicode.org/versions/Unicode6.0.0/>.		<http://www.unicode.org/versions/Unicode6.0.0/>.
			11.2. Informative References
			[RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and
			Registration Procedures", BCP 13, RFC 4288, December 2005.
	Authors' Addresses		Authors' Addresses
	Paul C. Bryan (editor)		Paul C. Bryan (editor)
	ForgeRock		ForgeRock
	Phone: +1 604 783 1481		Phone: +1 604 783 1481
	Email: pbryan@anode.ca		Email: pbryan@anode.ca
	Kris Zyp		Kris Zyp
	SitePen (USA)		SitePen (USA)
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