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Versions: 00 01 draft-ietf-json-i-json

Internet Engineering Task Force                           T.B. Bray, Ed.
Internet-Draft                                              Google, Inc.
Intended status: Standards Track                           July 11, 2013
Expires: January 12, 2014


                       The I-JSON Message Format
                          draft-bray-i-json-00

Abstract

   I-JSON is a restricted profile of JSON designed to maximize
   interoperability and increase confidence that software can process it
   successfully with predictable results.

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
   Task Force (IETF).  Note that other groups may also distribute
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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 January 12, 2014.

Copyright Notice

   Copyright (c) 2013 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
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   publication of this document.  Please review these documents
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents



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   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  I-JSON Messages . . . . . . . . . . . . . . . . . . . . . . .   2
     2.1.  Self-identification . . . . . . . . . . . . . . . . . . .   3
     2.2.  Encoding and Characters . . . . . . . . . . . . . . . . .   3
     2.3.  Numbers . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.4.  Object member names . . . . . . . . . . . . . . . . . . .   3
   3.  Software Behavior . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   RFC4627bis specifies a data format called JSON which has come to be
   widely used in Internet protocols.  For historical reasons, that RFC
   allows the use of language idioms and text encoding patterns which
   are likely to lead to interoperability problems and software
   breakage, particularly when a program receiving JSON data uses
   automated software to map it into native programming-language
   structures or database records.

   This document specifies I-JSON, short for "Internet JSON".  I-JSON
   Messages are also JSON texts per RFC4627bis, but with improved
   interoperability and lower risk of breakage in receiving software.

1.1.  Terminology

   The terms "object", "member", "array", "number", "name", and "string"
   in this document are to be interpreted as described in RFC4627bis.

1.2.  Requirements Language

   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 RFC 2119 [RFC2119].

2.  I-JSON Messages

   An I-JSON Message is a "JSON text" as defined by RFC4626bis and
   therefore MUST be either an object or an array.

   For maximum flexibility, an I-JSON Message SHOULD be an object.  This
   allows self-identification (see below) and also allows protocol



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   designers to add new data items to messages, should that become
   necessary, without breaking existing deployments.  In other words, it
   makes a Must-Ignore policy possible.

2.1.  Self-identification

   If an I-JSON Message is an object, it MAY self-identify by including
   a member whose name is "urn:ietf:i-json" and whose value is an
   object, which MUST be the first member of the top-level object.  This
   specification does not constrain the content of the object; it might
   be useful for further profiling in future specifications.

   When an I-JSON message is an HTTP request or response body,
   identified with the Internet Media Type "application/json" or
   alternately of the "+json" form as described in RFC 6838 [RFC6838], a
   media-type parameter MAY be included of the form "profile=i-json"; so
   the whole media type would be "application/json; profile=i-json" or
   "application/XXX+json; profile=i-json".

2.2.  Encoding and Characters

   I-JSON Messages MUST be encoded using UTF-8.

   String values of object members in I-JSON Messages MUST NOT include
   code points which identify Surrogates or Noncharacters (Unicode
   section 2.4), and SHOULD NOT include code points which identify
   Compatibility Characters (Unicode section 2.3) or Control characters
   (Unicode section 2.4).

   This applies both to characters encoded directly in UTF-8 and to
   those which are escaped; thus, "\uDDDD" is illegal.

2.3.  Numbers

   Number values of object members in I-JSON Messages must be exactly
   representable as IEEE 754:2008 64-bit binary floating point numbers.

   Numbers of greater length are likely to cause breakage when the
   receiving program is in a statically-typed language or in JavaScript.
   For applications such as cryptography, where much larger numbers are
   reasonably required, it is RECOMMENDED to transmit large numbers as
   strings.  This requires that the receiving program understand the
   intended semantic of the member.

2.4.  Object member names

   Objects in I-JSON Messages MUST NOT have members with duplicate
   names.



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3.  Software Behavior

   When software reads data which it expects to be an I-JSON message,
   but the data violates one of the MUST constraints in the previous
   section (for example, contains an object with a duplicate key, or a
   UTF-8 encoding error), that software MUST NOT trust nor act on the
   content of the message.

   Designers of protocols which use I-JSON messages SHOULD provide a
   way, in this case, for the receiver of the erroneous data to signal
   the problem to the sender.

4.  Acknowledgements

   I-JSON is entirely dependent on the design of JSON, largely due to
   Douglas Crockford.  The specifics were strongly influenced by the
   contributors to the design of RFC4627bis on the IETF JSON Working
   Group.

5.  IANA Considerations

   IANA will need to define a new entry in the "urn:ietf" namespace,
   "urn:ietf:i-json", to support I-JSON self-identification.

   IANA will need to register the "profile" parameter and value "i-json"
   for the "application/json" media type, and take steps to allow the
   use of this parameter on media types of the form "application/
   XXX+json".

6.  Security Considerations

   All the security considerations which apply to JSON (see RFC4627bis)
   apply to I-JSON.  There are no additional security considerations
   specific to I-JSON.

7.  Normative References

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

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

   [RFC6838]  Freed, N., Klensin, J., and T. Hansen, "Media Type
              Specifications and Registration Procedures", BCP 13, RFC
              6838, January 2013.

Author's Address



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   Tim Bray (editor)
   Google, Inc.

   Email: tbray@textuality.com
   URI:   https://www.tbray.org/













































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