Network Working Group J. Snell Internet-Draft February 24, 2012 Intended status: Standards Track Expires: August 27, 2012 Additional Link Relation Types draft-snell-additional-link-relations-01 Abstract This specification defines a number of additional Link Relation Types. Status of this Memo This Internet-Draft is submitted to IETF 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 http://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 August 27, 2012. Copyright Notice Copyright (c) 2012 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 (http://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. Snell Expires August 27, 2012 [Page 1] Internet-Draft HTTP Prefer February 2012 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. "implements" . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. "privacy-policy" . . . . . . . . . . . . . . . . . . . . . . . 3 4. "terms-of-service" . . . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.1. Normative References . . . . . . . . . . . . . . . . . . . 6 7.2. Informative References . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6 Snell Expires August 27, 2012 [Page 2] Internet-Draft HTTP Prefer February 2012 1. Introduction This specification defines a number of additional Link Relation Types for a variety of common linking scenarios. In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in [RFC2119]. 2. "implements" The "implements" Link relation can be used to refer to a resource that specifies the behavior implemented by the link's context. Links using the "implements" link relation can point either to formal specification documents such as RFC's, Internet-Drafts, W3C Recommendations, or to informal and possibly vendor specific documents that describe implementation details. For example, an HTTP client that implements the Atom Publishing Protocol [RFC5023] could include an "implements" Link (per [RFC5988]) within the HTTP Request referencing RFC 5023: POST /collection HTTP/1.1 Host: example.org Content-Type: application/atom+xml; type=entry Link: ; rel="implements" ; rel="privacy-policy" ... ... ... Privacy Policy ... Note that in the absence of clear legal obligations placed on an entity either through contract or law, the presence of a "privacy- policy" Link does not constitute a legally binding obligation on the part of the service. The linked resource MUST be interpreted as only a description of the expected practice. 4. "terms-of-service" The "terms-of-service" Link relation can be used to refer to a resource describing the Terms of Service associated with the link's context. The Terms of Service can be any resource that describes the rules to which a consumer of the service must agree to follow when using the service provided by the link's context. For example, an HTTP server can include "terms-of-service" Links within all HTTP Responses using any combination of Link headers or links embedded in the response payload: Snell Expires August 27, 2012 [Page 4] Internet-Draft HTTP Prefer February 2012 HTTP/1.1 200 OK Content-Type: text/html Link: ; rel="terms-of-service" ... ... ... Privacy Policy ... It must be noted that the Terms of Service linked to using this link relation carries no legal weight and can be ignored with impunity in the absence of an explicit, legally enforceable contract. The linked Terms of Service are simply a notice of the terms that may be expected to apply once a contract is established. 5. IANA Considerations The Registry of Link Relations should be updated with the following entries: o Relation Name: implements o Description: Refers to a specification implemented by the link's context. o Reference: This specification. o Relation Name: privacy-policy o Description: Refers to a Privacy Policy associated with the link's context. o Reference: This specification. o Relation Name: terms-of-service o Description: Refers to the Terms of Service associated with the link's context. o Reference: This specification. Snell Expires August 27, 2012 [Page 5] Internet-Draft HTTP Prefer February 2012 6. Security Considerations Implementors should note that the presence of a "privacy-policy" Link provides no guarantee that personal information collected and used by a resource will be handled in the manner described by the linked resource. Publishers of Privacy Policy resources linked to using the "privacy- policy" Link relation type SHOULD provide a clear and simple mechanism for signaling when changes to the Privacy Policy resource have been made, such as generating a new Entity Tag for the resource or generating a hash over the Privacy Policy's content. There are no additional security concerns introduced by the "terms- of-service" and "implements" Link relations. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 7.2. Informative References [RFC5023] Gregorio, J. and B. de hOra, "The Atom Publishing Protocol", RFC 5023, October 2007. [RFC5988] Nottingham, M., "Web Linking", RFC 5988, October 2010. Author's Address James M Snell Email: jasnell@gmail.com Snell Expires August 27, 2012 [Page 6]