Constrained Internationalized Resource Identifiers
draft-hartke-t2trg-ciri-00

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Thing-to-Thing Research Group                                  K. Hartke
Internet-Draft                                                  Ericsson
Intended status: Experimental                           October 22, 2018
Expires: April 25, 2019

           Constrained Internationalized Resource Identifiers
                       draft-hartke-t2trg-ciri-00

Abstract

   This document specifies Constrained Internationalized Resource
   Identifier References, a serialization of Internationalized Resource
   Identifier (IRI) references that encodes the IRI components as
   Concise Binary Object Representation (CBOR) data items rather than a
   string of characters.  This intends to simplify parsing, reference
   resolution, and comparison of IRIs in Constrained RESTful
   Environments (CoRE).

Status of This Memo

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   This Internet-Draft will expire on April 25, 2019.

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   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Hartke                   Expires April 25, 2019                 [Page 1]
Internet-Draft              Constrained IRIs                October 2018

   the Trust Legal Provisions and are provided without warranty as
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Notation . . . . . . . . . . . . . . . . . .   3
   2.  Data Model  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Options . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Option Sequences  . . . . . . . . . . . . . . . . . . . .   4
   3.  CBOR  . . . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Python  . . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  Reference Resolution  . . . . . . . . . . . . . . . . . .   8
     4.2.  IRI Recomposition . . . . . . . . . . . . . . . . . . . .   9
     4.3.  CoAP Encoding . . . . . . . . . . . . . . . . . . . . . .  12
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  14
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  15
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   URI references [RFC3986] and, albeit less prevalently, IRI references
   [RFC3987] are the standard way to link to resources in hypertext
   formats like HTML [W3C.REC-html52-20171214] and the CoRE Link Format
   [RFC6690].  They encode the components of a resource reference either
   as an absolute URI/IRI or as a relative reference that must be
   resolved against a base URI/IRI to receive an absolute URI/IRI.

   URI and IRI references are strings of characters where the characters
   are chosen from a limited subset of the repertoires of US-ASCII and
   Unicode characters, respectively.  The individual components of a URI
   or IRI reference are delimited by a number of reserved characters,
   which necessitates the use of percent-encoding when these reserved
   characters are used in a non-delimiting function.  The resolution of
   references involves parsing URI/IRI references into their components,
   combining those components with the components of the base URI/IRI,
   merging paths, removing dot segments, and recomposing the result back
   into a character string.

   Altogether, the proper processing of URIs is quite complex.  This can
   be a problem particularly in constrained environments [RFC7228],
   where devices often have severe code size limitations.  As a result,
   many implementations in these environments choose to implement only