Imported debug from /usr/lib/site-python/debug.pyc draft-bray-i-json-01 - The I-JSON Message Format
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Versions: 00 01 draft-ietf-json-i-json

Internet Engineering Task Force                             T. Bray, Ed.
Internet-Draft                                              Google, Inc.
Intended status: Standards Track                        January 06, 2014
Expires: July 10, 2014


                       The I-JSON Message Format
                          draft-bray-i-json-01

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 July 10, 2014.

Copyright Notice

   Copyright (c) 2014 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
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   described in the Simplified BSD License.





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Table of Contents

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

1.  Introduction

   RFC4627bis describes the JSON data interchange format, which is
   widely used in Internet protocols.  For historical reasons, that
   specification 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.  RFC4627 describes practices which
   may be used to avoid these interoperability problems.

   This document specifies I-JSON, short for "Internet JSON".  The unit
   of definition is the "I-JSON message".  I-JSON messages are also
   "JSON texts" as defined in RFC4627bis but with certain extra
   constraints which enforce the good interoperability practices
   described in that specification.

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].









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2.  I-JSON Messages

   An I-JSON message is a JSON object, as defined by RFC4626bis.  This
   allows protocol 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.

   When an I-JSON message is transmitted over the Internet, since it is
   a JSON text as defined in RFC4627bis, it may be described using the
   Internet Media Type "application/json".  Specifications whose
   messages are specified to be I-JSON messages SHOULD specify the use
   of a media type of the form "application/XXX+i-json", where XXX is
   specific to the specification.

2.1.  Encoding and Characters

   I-JSON messages MUST be encoded using UTF-8 [RFC3629].

   Object member names, and string values in arrays and object members,
   MUST NOT include code points which identify Surrogates or
   Noncharacters.

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

2.2.  Numbers

   Software which implements IEEE 754-2008 binary64 (double precision)
   numbers [IEEE754] is generally available and widely used.
   Implementations which generate I-JSON messages MUST NOT assume that
   receiving implementations can process numeric values with greater
   magnitude or precision than provided by those numbers.  I-JSON
   messages SHOULD NOT include numbers which express greater magnitude
   or precision than an IEEE 754 double precision number provides, for
   example 1E400 or 3.141592653589793238462643383279.

   For applications such as cryptography, where much larger numbers are
   reasonably required, it is RECOMMENDED to encode them in JSON string
   values.  This requires that the receiving program understand the
   intended semantic of the value.

2.3.  Object constraints

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






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   Implementations which generate I-JSON messages MUST NOT assume that
   the order of object members in those messages is available to
   software which receives them.

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.  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.

6.  Normative References

   [IEEE754]  IEEE, "IEEE Standard for Floating-Point Arithmetic", 2008,
              <http://grouper.ieee.org/groups/754/>.

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

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, November 2003.

   [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.





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Author's Address

   Tim Bray (editor)
   Google, Inc.

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












































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