< draft-ietf-appsawg-json-pointer-01.txt		draft-ietf-appsawg-json-pointer-02.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: September 10, 2012 SitePen (USA)		Expires: January 5, 2013 SitePen (USA)
	March 9, 2012		M. Nottingham, Ed.
			Rackspace
			July 4, 2012
	JSON Pointer		JSON Pointer
	draft-ietf-appsawg-json-pointer-01		draft-ietf-appsawg-json-pointer-02
	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 32 ¶		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 September 10, 2012.		This Internet-Draft will expire on January 5, 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 12 ¶		skipping to change at page 2, line 12 ¶
	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
	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 . . . . . . . . . . . . 4		6. URI Fragment Identifier Representation . . . . . . . . . . . . 5
	7. Error Handling . . . . . . . . . . . . . . . . . . . . . . . . 4		7. Error Handling . . . . . . . . . . . . . . . . . . . . . . . . 5
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
	9. Security Considerations . . . . . . . . . . . . . . . . . . . . 5		9. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
	10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5		10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
	11. Normative References . . . . . . . . . . . . . . . . . . . . . 5		11. Normative References . . . . . . . . . . . . . . . . . . . . . 6
	Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . . 5		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
	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] text document. This syntax is intended to be easily		(JSON) [RFC4627] document. It is intended to be easily expressed in
	expressed in JSON string values and Uniform Resource Identifier (URI)		JSON string values and Uniform Resource Identifier (URI) [RFC3986]
	[RFC3986] fragment identifiers.		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 '/' (%x2F) or '^' (%x5E) characters,		If a reference token contains '~' (%x7E) or '/' (%x2F) characters,
	such characters MUST each be prefixed (escaped) with a '^' (%x5E)		they MUST be encoded as '~0' and '~1' respectively.
	character.
	ABNF syntax:		ABNF syntax:
	json-pointer = *( "/" reference-token )		json-pointer = *( "/" reference-token )
	reference-token = *( unescaped / escaped )		reference-token = *( unescaped / escaped )
	unescaped = %x00-2E / %x30-5B / %x5D-10FFFF		unescaped = %x00-2E / %x30-7D / %x7F-10FFFF
	escaped = "^" ( "/" / "^" )		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.		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 text document and completes with a reference to some
	value within the document. Each reference token in the JSON Pointer		value within the document. Each reference token in the JSON Pointer
	is sequentially evaluated.		is sequentially evaluated.
	Evaluation of each reference token begins by unescaping any escaped		Evaluation of each reference token begins by decoding any escaped
	character sequence; this is performed by removing the '^' (escape)		character sequence; this is performed by first transforming any
	prefix. The reference token then modifies which value is referenced		occurrence of the sequence '~1' to '/', then transforming any
	according to the following scheme:		occurrence of the sequence '~0' to '~'.
			The reference token then modifies which value is referenced according
			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 identified by		referenced value is the object member with the name (after
	the reference token. The member name is equal to the token if it		unescaping any backslash escape sequences that can occur in a JSON
	has the same number of Unicode characters as token and their		string) identified by the reference token. The member name is
	codepoints are positionwise equal. If a referenced member name is		equal to the token if it has the same number of Unicode characters
	not unique in an object, the member that is referenced is		as token and their code points are position-wise equal. If a
	undefined.		referenced member name is not unique in an object, the member that
			is referenced is undefined.
	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, and the new referenced value is the array element		integer value (possibly with leading zeros), and the new
	with the zero-based index identified by the token.		referenced value is the array element with the zero-based index
			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, the
	implementation MAY evaluate each token against a concrete value, and		implementation MAY evaluate each token against a concrete value, and
	terminate evaluation with an error condition if a evaluation fails to		terminate evaluation with an error condition if a evaluation fails to
	resolve a concrete value.		resolve a concrete value (see Section 7).
	5. JSON String Representation		5. JSON String Representation
	A JSON Pointer MAY 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
			{
			"foo": ["bar", "baz"],
			"": 0
			"a/b": 1,
			"c%d": 2,
			"e^f": 3,
			"g|h": 4,
			"i\\j": 5,
			"k\"l": 6,
			" ": 7,
			"m~n": 8
			}
			Then the following JSON strings evaluate to the accompanying values:
			"" // the whole document
			"/foo" ["bar", "baz"]
			"/foo/0" "bar"
			"/" 0
			"/a~1b" 1
			"/c%d" 2
			"/e^f" 3
			"/g|h" 4
			"/i\\j" 5
			"/k\"l" 6
			" " 7
			"m~0n" 8
	6. URI Fragment Identifier Representation		6. URI Fragment Identifier Representation
	A JSON Pointer MAY be represented in a URI fragment identifier. The		A JSON Pointer can be represented in a URI fragment identifier. by
	JSON pointer MUST be UTF-8 [RFC3629] encoded as octets; octets not in		encoding it into octets, using UTF-8 [RFC3629], percent-encoding
	the URI "unreserved" set SHOULD be percent-encoded, per [RFC3986],		those characters not allowed by the fragment rule in [RFC3986].
	section 2.5.
			Given the same example document as above, the following URI fragment
			identifiers evaluate to the accompanying values:
			# // the whole document
			#/foo ["bar", "baz"]
			#/foo/0 "bar"
			#/ 0
			#/a~1b 1
			#/c%25d 2
			#/e%5Ef 3
			#/g%7Ch 4
			#/i%5Cj 5
			#/k%22l 6
			#/%20 7
			#/m~0n 8
	7. Error Handling		7. Error Handling
	In the event of an error condition, evaluation of the JSON Pointer		In the event of an error condition, evaluation of the JSON Pointer
	fails to complete.		fails to complete.
			This includes, but is not limited to:
			o Invalid pointer syntax
			o A pointer that references a non-existent value
			This specification does not define how errors are handled; an
			application of JSON Pointer SHOULD specify the impact and handling of
			each type of error.
			For example, some applications might stop pointer processing upon an
			error; others may attempt to recover from missing values by inserting
			default ones.
	8. IANA Considerations		8. IANA Considerations
	This document has no IANA actions.		TBD
	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)
			character, which may not be representable in all programming
			languages.
	10. Acknowledgements		10. Acknowledgements
	The following individuals contributed ideas, feedback and wording,		The following individuals contributed ideas, feedback and wording to
	which contributed to the content of 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, Mark Nottingham, Drew		Duerst, Bjoern Hoehrmann, James H. Manger, Drew Perttula, Julian
	Perttula, Julian Reschke.		Reschke.
	11. Normative References		11. 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
	skipping to change at page 5, line 42 ¶		skipping to change at page 7, line 17 ¶
	[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/>.
	Appendix A. Examples
	The following examples illustrate the use of JSON Pointers in URI
	fragments for a JSON text document located at
	http://example.com/example.json, with the following value:
	{
	"foo": {
	"bar": [ "element0", "element1" ],
	"inner object": {
	"baz": "qux"
	}
	}
	http://example.com/example.json#
	Resolves to the object value at the root of the JSON text
	document.
	http://example.com/example.json#/foo
	Resolves to the object value of the "foo" member in the root
	object.
	http://example.com/example.json#/foo/inner%20object
	Resolves to the object value of the "inner object" member in the
	"foo" object value in the root object.
	http://example.com/example.json#/foo/inner%20object/baz
	Resolves to the string value "qux", which is the value of the
	"baz" member in the "inner object" member in the "foo" member in
	the root object.
	http://example.com/example.json#/foo/bar/0
	Resolves to the string value "element0", which is the first value
	in the "bar" array in the "foo" member in the root object.
	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)
	Phone: +1 650 968 8787		Phone: +1 650 968 8787
	Email: kris@sitepen.com		Email: kris@sitepen.com
			Mark Nottingham (editor)
			Rackspace
			Email: mnot@mnot.net
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