< draft-ietf-appsawg-json-pointer-06.txt		draft-ietf-appsawg-json-pointer-07.txt >
	Applications Area Working Group P. Bryan, Ed.		Applications Area Working Group P. Bryan, Ed.
	Internet-Draft Salesforce.com		Internet-Draft Salesforce.com
	Intended status: Informational K. Zyp		Intended status: Informational K. Zyp
	Expires: June 8, 2013 SitePen (USA)		Expires: June 14, 2013 SitePen (USA)
	M. Nottingham, Ed.		M. Nottingham, Ed.
	Akamai		Akamai
	December 5, 2012		December 11, 2012
	JSON Pointer		JSON Pointer
	draft-ietf-appsawg-json-pointer-06		draft-ietf-appsawg-json-pointer-07
	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 June 8, 2013.		This Internet-Draft will expire on June 14, 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 15 ¶		skipping to change at page 2, line 15 ¶
	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 . . . . . . . . . . . . . . . . . . . . . . . . 6		7. Error Handling . . . . . . . . . . . . . . . . . . . . . . . . 6
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
	9. Security Considerations . . . . . . . . . . . . . . . . . . . . 6		9. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
	10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7		10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
	11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7		11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
	11.1. Normative References . . . . . . . . . . . . . . . . . . . 7		11.1. Normative References . . . . . . . . . . . . . . . . . . . 7
	11.2. Informative References . . . . . . . . . . . . . . . . . . 7		11.2. Informative References . . . . . . . . . . . . . . . . . . 7
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
	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 as well as Uniform Resource Identifier (URI)		JSON string values as well as Uniform Resource Identifier (URI)
	[RFC3986] 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 (ABNF) [RFC5234] notation.		Backus-Naur Form (ABNF) [RFC5234] 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 (see [RFC4627], Section 3)
	more reference tokens, each prefixed by a '/' (%x2F) character.		containing a sequence of zero or more reference tokens, each prefixed
			by a '/' (%x2F) character.
	Since the characters '~' (%x7E) and '/' (%x2F) have a special meaning		Because the characters '~' (%x7E) and '/' (%x2F) have special
	in JSON Pointer, they need to be encoded as '~0' and '~1'		meanings in JSON Pointer, '~' needs to be encoded as '~0' and '/'
	respectively, when appearing in a reference token.		needs to be encoded as '~1' when these characters appear in a
			reference token.
	Its ABNF syntax is:		The ABNF syntax of a JSON Pointer 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
			; %x2F ('/') and %x7E ('~') are excluded from 'unescaped'
	escaped = "~" ( "0" / "1" )		escaped = "~" ( "0" / "1" )
			; representing '~' and '/', respectively
	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 document and completes with a reference to some value		value of a JSON document and completes with a reference to some value
	within the document. Each reference token in the JSON Pointer is		within the document. Each reference token in the JSON Pointer is
	sequentially evaluated.		sequentially evaluated. By performing the substitutions in this
			order, an implementation avoids the error of turning '~01' first into
			'~1' and then into '/', which would be incorrect (the string '~01'
			correctly becomes '~1' after transformation).
	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:
	o If the currently referenced value is a JSON object, the new		o 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 identified by
	the reference token. The member name is equal to the token if it		the reference token. The member name is equal to the token if it
	has the same number of Unicode characters as token and their code		has the same number of Unicode characters as token and their code
	points are position-wise equal. If a referenced member name is		points are position-wise equal. No Unicode character
	not unique in an object, the member that is referenced is		normalization is performed. If a referenced member name is not
	undefined, and evaluation fails (see below).		unique in an object, the member that is referenced is undefined,
			and evaluation fails (see below).
	o If the currently referenced value is a JSON array, the reference		o If the currently referenced value is a JSON array, the reference
	token MUST contain either:		token MUST contain either:
	* characters that represent an unsigned base-10 integer value		* characters that represent an unsigned base-10 integer value
	(possibly with leading zeros), making the new referenced value		(possibly with leading zeros), making the new referenced value
	the array element with the zero-based index identified by the		the array element with the zero-based index identified by the
	token, or		token, or
	* exactly the single character "-", making the new referenced		* exactly the single character "-", making the new referenced
	skipping to change at page 6, line 44 ¶		skipping to change at page 7, line 8 ¶
	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
	This document has no impact upon IANA.		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. Therefore, applications using JSON Pointer should anticipate
	precautions.		this by defining how a pointer that does not resolve ought to be
			handled.
	Note that JSON pointers can contain the NUL (Unicode U+0000)		Note that JSON pointers can contain the NUL (Unicode U+0000)
	character. Care is needed not to misinterpret this character in		character. Care is needed not to misinterpret this character in
	programming languages that use NUL to mark the end of a string.		programming languages that use NUL to mark the end of a string.
	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:
	skipping to change at page 7, line 34 ¶		skipping to change at page 7, line 45 ¶
	[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.
	[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
	6.0", October 2011,
	<http://www.unicode.org/versions/Unicode6.0.0/>.
	11.2. Informative References		11.2. Informative References
	[RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and		[RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and
	Registration Procedures", BCP 13, RFC 4288, December 2005.		Registration Procedures", BCP 13, RFC 4288, December 2005.
	Authors' Addresses		Authors' Addresses
	Paul C. Bryan (editor)		Paul C. Bryan (editor)
	Salesforce.com		Salesforce.com
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