CoRE C. Amsuess Internet-Draft September 27, 2018 Expires: March 31, 2019 Expressing indirection in a dereferencing content type draft-amsuess-core-dereference-type-latest Abstract [ See introduction ] 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 March 31, 2019. Copyright Notice Copyright (c) 2018 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 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. Amsuess Expires March 31, 2019 [Page 1] Internet-DraftExpressing indirection in a dereferencing coSeptember 2018 1. Introduction The topic of providing a content format that indicates that a particular URI should be dereferenced instead of using the payload itself has come up time and again in CoRE [citation needed]. Nobody has done anything about it. [TDB: Check whether that's actually the case.] Until now. 2. The Dereference Link type The Dereference Link type is a media type for use with RESTful systems that carries a very particular piece of information: That a representation of the requested resource is available at a given location. The location of that representation is expressed in an [RFC6690] link format document that contains only a single link whose target is expressed as a URI (ie. not a relative reference). The link MAY contain target attributes, which the client MAY ignore. [ TBD: Detailed deliberations on whether to use link-format, just a plain URI, links-json or what so not - and whether a relative refrence can make sense. ] A Dereference Link always indicates semantic equivalence: It indicates that any information derived from its link target could also have been obtained from the requested resource. It does not mean that any resource representation obtained of the target resource could be literally substituted for it. This specification does not prescribe any behavior to recipients of a Dereference Link, it is up to application descriptions to explore its security implications and to describe what a recipient may or may not do about it. 2.1. Comparison to media-type specific inclusion Various media types contain built-in facilities to express the same intent as a Derefere Link: A HTML document can contain an "