The Series Transfer Pattern (STP)
draft-bormann-t2trg-stp-03

Document Type Active Internet-Draft (individual)
Last updated 2020-04-07
Stream (None)
Intended RFC status (None)
Formats plain text html xml pdf htmlized (tools) htmlized bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                         C. Bormann
Internet-Draft                                    Universit├Ąt Bremen TZI
Intended status: Informational                                 K. Hartke
Expires: 10 October 2020                                        Ericsson
                                                            8 April 2020

                   The Series Transfer Pattern (STP)
                       draft-bormann-t2trg-stp-03

Abstract

   Many applications make use of Series of data items, i.e., an array of
   data items where new items can be added over time.  Where such Series
   are to be made available using REST protocols such as CoAP or HTTP,
   the Series has to be mapped into a structure of one or more resources
   and a protocol for a client to obtain the Series and to learn about
   new items.

   Various protocols have been standardized that make Series-shaped data
   available, with rather different properties and objectives.  The
   present document is an attempt to extract a common underlying pattern
   and to define media types and an access scheme that can be used right
   away for further protocols that provide Series-shaped data.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   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 10 October 2020.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Bormann & Hartke         Expires 10 October 2020                [Page 1]
Internet-Draft      The Series Transfer Pattern (STP)         April 2020

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Simplified BSD License text
   as described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Objectives  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  A REST Series Transfer Pattern (STP)  . . . . . . . . . . . .   4
     3.1.  Basic collections . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Pagination and Observing linked lists . . . . . . . . . .   5
     3.3.  The "cursor" pattern  . . . . . . . . . . . . . . . . . .   7
   4.  IANA considerations . . . . . . . . . . . . . . . . . . . . .   8
   5.  Security considerations . . . . . . . . . . . . . . . . . . .   9
   6.  Informative References  . . . . . . . . . . . . . . . . . . .   9
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   (TO DO: Insert an extended form of the abstract first here, expanding
   the reference to [RFC7230] and [RFC7252] in the process.)

   Examples for protocols that provide Series-shaped data are:

   *  The Atom Syndication Format [RFC4287] defines _feeds_ as Series of
      _entries_ (links plus some metadata, which can often be much of
      the content of an entry), where a feed is represented by a
      collection resource that contains just a small number of the most
      recent entries.  By polling a feed, a client can contain a fresh
      view of the Series, with a focus on recent items.  If the client
      does not poll often enough, it will _miss_ items.

   *  Messaging protocols such as XMPP or SIMPLE transfer series of what
      is often called "Instant Messages".  A publish/subscribe mechanism
      allows a client to select sequences of messages that it is
      interested in.

   *  Mail servers that provide interactive access to stored messages
      present a Series to their clients.  Obviously, loss of messages is
      frowned upon.

Bormann & Hartke         Expires 10 October 2020                [Page 2]
Internet-Draft      The Series Transfer Pattern (STP)         April 2020

   *  CoAP Observe allows a client to observe a resource as it changes;
      the client can collect the changes into a Series.  Observe is
      focused on eventual consistency: a fresher data items simply
Show full document text