Constrained Internationalized Resource Identifiers
draft-hartke-t2trg-ciri-02

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Thing-to-Thing Research Group                                  K. Hartke
Internet-Draft                                                  Ericsson
Intended status: Experimental                             March 11, 2019
Expires: September 12, 2019

           Constrained Internationalized Resource Identifiers
                       draft-hartke-t2trg-ciri-02

Abstract

   Constrained Internationalized Resource Identifiers are an alternate
   serialization of Uniform Resource Identifiers (URIs) that encodes the
   URI components in Concise Binary Object Representation (CBOR) instead
   of a string of characters.  This simplifies parsing, reference
   resolution, and comparison of URIs in environments with severe
   limitations on processing power, code size, and memory size.

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   This Internet-Draft will expire on September 12, 2019.

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   Copyright (c) 2019 IETF Trust and the persons identified as the
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Hartke                 Expires September 12, 2019               [Page 1]
Internet-Draft              Constrained IRIs                  March 2019

   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Notational Conventions  . . . . . . . . . . . . . . . . .   3
   2.  Data Model  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Options . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Option Sequences  . . . . . . . . . . . . . . . . . . . .   5
   3.  CBOR  . . . . . . . . . . . . . . . . . . . . . . . . . . . .   7
   4.  Python  . . . . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Reference Resolution  . . . . . . . . . . . . . . . . . .   9
     4.2.  URI Recomposition . . . . . . . . . . . . . . . . . . . .  10
     4.3.  CoAP Encoding . . . . . . . . . . . . . . . . . . . . . .  12
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  14
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  15
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  15
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   Uniform Resource Identifier (URI) references [RFC3986] are the
   standard way to link to resources in hypertext formats such as HTML
   [W3C.REC-html52-20171214] or the HTTP "Link" header field [RFC8288].
   A URI reference is either a URI or a relative reference that must be
   resolved against a base URI.

   URI references are strings of characters chosen from the repertoire
   of US-ASCII characters.  The individual components of a URI 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.  One component can also contain special
   dot-segments that affect how the component is to be interpreted.  The
   resolution of URI references involves parsing the character string
   into its components, combining those components with the components
   of a base URI, merging path components, removing dot-segments, and
   recomposing the result back into a character string.

   Overall, the proper processing of URIs is quite complicated.  This
   can be a problem in particular in constrained environments [RFC7228],
   where devices often have severe code size limitations.  As a result,
   many implementations in these environments choose to support only an
   ad-hoc, informally-specified, bug-ridden, non-interoperable subset of