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Versions: 00 01 02 draft-ietf-appsawg-json-pointer

Internet Engineering Task Force                            P. Bryan, Ed.
Internet-Draft                                        ForgeRock US, Inc.
Intended status: Informational                                    K. Zyp
Expires: April 22, 2012                                    SitePen (USA)
                                                        October 20, 2011


                              JSON Pointer
                    draft-pbryan-zyp-json-pointer-01

Abstract

   JSON Pointer defines a syntax for identifying a specific value within
   a JSON document.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 22, 2012.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.





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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Syntax  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Evaluation  . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   5.  Error Handling  . . . . . . . . . . . . . . . . . . . . . . . . 4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   8.  Normative References  . . . . . . . . . . . . . . . . . . . . . 4
   Appendix A.  Examples . . . . . . . . . . . . . . . . . . . . . . . 4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 5







































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1.  Introduction

   This specification defines JSON Pointer, a syntax for identifying a
   specific value within a JSON [RFC4627] text document.  The syntax is
   intended to be expressed in a JSON string value or the URI fragment
   identifier of a resource that has a JSON representation.


2.  Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   This specification expresses syntax rules using ABNF [RFC5234]
   (Augmented Backus-Naur Form) notation.  Additionally, it uses the
   following rules from URI syntax [RFC3986]: "unreserved" and "pct-
   encoded".


3.  Syntax

   A JSON Pointer is a sequence of zero or more reference tokens, each
   prefixed by a "/" (%x2F) character.  Each reference token is a
   sequence of unreserved and/or percent-encoded characters, per
   [RFC3986].

   json-pointer = *( "/" reference-token )
   reference-token = *( unreserved / pct-encoded )

   Unreserved characters in reference tokens SHOULD be percent-encoded,
   per [RFC3986], and MUST be so encoded as "%2F" if the character is
   "/" to avoid being interpreted as a reference token prefix.

   It is an error condition if a JSON Pointer does not conform to this
   syntax.


4.  Evaluation

   Evaluation begins with a reference to the root value of a JSON text
   document, and completes with a reference to some value within the
   same document.  Each token in the JSON Pointer sequence is evaluated,
   changing the referenced value according to the following scheme:

   If the currently referenced value is a JSON object, the new
   referenced value is the object property with the name identified by
   the token.  If the currently referenced value is a JSON array, the



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   new referenced value is the array element with the zero-based index
   identified by the token.

   If a reference token is being evaluated against a concrete JSON text
   document, the implementation MAY evaluate each token against the
   currently referenced concrete value, and terminate evaluation with an
   error condition should a reference token fail to resolve to a
   concrete value.


5.  Error Handling

   In the event of an error condition, evaluation of the JSON Pointer
   fails to complete.


6.  IANA Considerations

   This draft includes no request to IANA.


7.  Security Considerations

   A pointer is not guaranteed to resolve to a JSON value.
   Implementations of JSON Pointer should be aware of this and take
   appropriate precautions.


8.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, January 2005.

   [RFC4627]  Crockford, D., "The application/json Media Type for
              JavaScript Object Notation (JSON)", RFC 4627, July 2006.

   [RFC5234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234, January 2008.


Appendix A.  Examples






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   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" property in the root
      object.

   http://example.com/example.json#/foo/inner%20object
      Resolves to the object value of the "inner object" property 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" property in the "inner object" property in the "foo"
      property 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" property in the root object.


Authors' Addresses

   Paul C. Bryan (editor)
   ForgeRock US, Inc.
   201 NE Park Plaza Drive Suite 196
   Vancouver, WA  98684
   USA

   Phone: +1 604 783 1481
   Email: paul.bryan@forgerock.com







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   Kris Zyp
   SitePen (USA)
   530 Lytton Avenue
   Palo Alto, CA  94301
   USA

   Phone: +1 650 968 8787
   Email: kris@sitepen.com











































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