Internet Engineering Task Force (IETF)                          E. Wilde
Request for Comments: 8091                               CA Technologies
Category: Informational                                    February 2017
ISSN: 2070-1721

     A Media Type Structured Syntax Suffix for JSON Text Sequences

Abstract

   Structured syntax suffixes for media types allow other media types to
   build on them and make it explicit that they are built on an existing
   media type as their foundation.  This specification defines and
   registers "+json-seq" as a structured syntax suffix for JSON text
   sequences.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc8091.

Copyright Notice

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   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  The "+json-seq" Structured Syntax Suffix  . . . . . . . . . .   2
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   Media type structured syntax suffixes [RFC6838] were introduced as a
   way for a media type to signal that it is based on another media type
   as its foundation.  Some structured syntax suffixes were registered
   initially [RFC6839], including "+json", for the widely popular JSON
   format [RFC7159].

   JSON text sequences [RFC7464] is a recent specification in the JSON
   space that defines how a sequence of multiple JSON texts can be
   represented in one representation.  This document defines and
   registers the "+json-seq" structured syntax suffix in the "Structured
   Syntax Suffix Registry".

2.  Terminology

   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].

3.  The "+json-seq" Structured Syntax Suffix

   The use case for the "+json-seq" structured syntax suffix is the same
   as for "+json": It SHOULD be used by media types when parsing the
   JSON text sequence of a media type leads to a meaningful result, by
   simply using the generic JSON text sequence processing.

   Applications encountering such a media type can then either simply
   use generic processing if all they need is a generic view of the JSON
   text sequence, or they can use generic JSON text sequence tools for
   initial parsing and then implement their own specific processing on
   top of that generic parsing tool.

4.  IANA Considerations

   Structured Syntax Suffixes are registered within the "Structured
   Syntax Suffix Registry" maintained at
   <https://www.iana.org/assignments/media-type-structured-suffix>.

   IANA has registered the "+json-seq" structured syntax suffix in
   accordance with [RFC6838].

      Name: JSON Text Sequence

      +suffix: +json-seq

      References: [RFC7464], RFC 8091

      Encoding considerations: See [RFC7464] Section 2.2

      Fragment identifier considerations: The syntax and semantics of
      fragment identifiers specified for +json-seq SHOULD be as
      specified for "application/json-seq".  (At publication of this
      document, there is no fragment identification syntax defined for
      "application/json-seq".)

         The syntax and semantics for fragment identifiers for a
         specific "xxx/yyy+json-seq" SHOULD be processed as follows:

            For cases defined in +json-seq, where the fragment
            identifier resolves per the +json-seq rules, then process as
            specified in +json-seq.

            For cases defined in +json-seq, where the fragment
            identifier does not resolve per the +json-seq rules, then
            process as specified in "xxx/yyy+json-seq".

            For cases not defined in +json-seq, then process as
            specified in "xxx/yyy+json-seq".

      Interoperability considerations: n/a

      Security considerations: See [RFC7464] Section 3

      Contact: Applications and Real-Time Area Discussion
      (art@ietf.org), or any IESG-designated successor.

      Author/Change controller: The Applications and Real-Time Area
      Working Group.  IESG has change control over this registration.

5.  Security Considerations

   All the security considerations of JSON text sequences [RFC7464]
   apply.  They are as follows:

   All the security considerations of JSON [RFC7159] apply.  This format
   provides no cryptographic integrity protection of any kind.

   As usual, parsers must operate on input that is assumed to be
   untrusted.  This means that parsers must fail gracefully in the face
   of malicious inputs.

   Note that incremental JSON text parsers can produce partial results
   and later indicate failure to parse the remainder of a text.  A
   sequence parser that uses an incremental JSON text parser might treat
   a sequence like '<RS>"foo"<LF>456<LF><RS>' as a sequence of one
   element ("foo"), while a sequence parser that uses a non-incremental
   JSON text parser might treat the same sequence as being empty.  This
   effect, and texts that fail to parse and are ignored, can be used to
   smuggle data past sequence parsers that don't warn about JSON text
   failures.

   Repeated parsing and re-encoding of a JSON text sequence can result
   in the addition (or stripping) of trailing LF bytes from (to)
   individual sequence element JSON texts.  This can break signature
   validation.  JSON has no canonical form for JSON texts, therefore
   neither does the JSON text sequence format.

6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC6838]  Freed, N., Klensin, J., and T. Hansen, "Media Type
              Specifications and Registration Procedures", BCP 13,
              RFC 6838, DOI 10.17487/RFC6838, January 2013,
              <http://www.rfc-editor.org/info/rfc6838>.

   [RFC7464]  Williams, N., "JavaScript Object Notation (JSON) Text
              Sequences", RFC 7464, DOI 10.17487/RFC7464, February 2015,
              <http://www.rfc-editor.org/info/rfc7464>.

6.2.  Informative References

   [RFC6839]  Hansen, T. and A. Melnikov, "Additional Media Type
              Structured Syntax Suffixes", RFC 6839,
              DOI 10.17487/RFC6839, January 2013,
              <http://www.rfc-editor.org/info/rfc6839>.

   [RFC7159]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
              2014, <http://www.rfc-editor.org/info/rfc7159>.

Acknowledgements

   Thanks for comments and suggestions provided by Ben Campbell, Allan
   Doyle, Warren Kumari, Sean Leonard, Alexey Melnikov, Brian Raymor,
   and Peter Yee.

Author's Address

   Erik Wilde
   CA Technologies

   Email: erik.wilde@dret.net
   URI:   http://dret.net/netdret/