Network Working Group J. Snell Internet-Draft October 2006 Expires: April 4, 2007 Atom License Extension draft-snell-atompub-feed-license-10.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 4, 2007. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This memo defines an extension to the Atom Syndication Format for describing licenses associated with Atom feeds and entries. Snell Expires April 4, 2007 [Page 1] Internet-Draft Feed License October 2006 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Experimental Status . . . . . . . . . . . . . . . . . . . . 3 1.2. Notational Conventions . . . . . . . . . . . . . . . . . . 3 1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3 2. The "license" link relation . . . . . . . . . . . . . . . . . . 3 2.1. Unspecified License Links . . . . . . . . . . . . . . . . . 4 2.2. Example . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.3. Inherited Licenses . . . . . . . . . . . . . . . . . . . . 4 2.4. Relationship with the "atom:rights" element . . . . . . . . 5 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7 Intellectual Property and Copyright Statements . . . . . . . . . . 8 Snell Expires April 4, 2007 [Page 2] Internet-Draft Feed License October 2006 1. Introduction This document defines an extension to the Atom Syndication Format that can be used to describe the explicit rights that have been granted to consumers of an Atom feed or entry. 1.1. Experimental Status Describing licenses using the mechanisms defined in this specification is currently considered to be largely experimental. While it is a common practice for feed publishers to associate licenses with syndicated content, there are still very few feed consumers that utilize such metadata and the effectiveness of doing so is still largely unknown. As it is not yet certain how these mechanisms will be used, implementations and feedback are encouraged. 1.2. Notational Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, [RFC2119]. 1.3. Terminology The term "link relation" refers to the value of the Atom link elements "rel" attribute as defined in section 4.2.7.2 of [RFC4287]. The term "license" refers to a potentially machine-readable description of explicit rights, and associated obligations, that have been granted to consumers of an Atom feed or entry. 2. The "license" link relation The "license" link relation can be used to associate licenses with a feed or entry. Feed and entry elements MAY contain any number of "license" link relations but MUST NOT contain more than one with the same combination of href and type attribute values. The IRI specified by the link's 'href' attribute SHOULD be dereferenceable to return a representation of the license. The license representation MAY be machine readable. Feeds and entries can be dual-licensed by including multiple "license" link relations specifying different href attribute values. If multiple license link relations are specified, each SHOULD contain a title attribute specifying a human-readable label for the license. Snell Expires April 4, 2007 [Page 3] Internet-Draft Feed License October 2006 2.1. Unspecified License Links A publisher can use an "unspecified license link" (a "license" link relation with an href attribute value equal to "http://purl.org/atompub/license#unspecified") to indicate that a feed or license has not been explicitly linked to a license description. A feed or entry containing an unspecified license link MUST NOT contain any other license link relations. 2.2. Example http://www.example.com/myfeed My Example Feed 2005-07-28T12:00:00Z Copyright (c) 2005. Some rights reserved. This feed is licensed under a Creative Commons Attribute-NonCommercial Use License. It contains material originally published by Jane Smith at http://www.example.com/entries/1 under the Creative Commons Attribute License. James tag:entries.org,2005:1 Atom Powered Robots Run Amok 2005-06-28T12:00:00Z Atom Powered Robots Run Amok Jane Smith 2.3. Inherited Licenses The license on a feed MAY be inherited by entries. Generally, a more specific license overrides the less specific license. More specifically, if an entry has any license link relations at all, including the "undefined" license, it does not inherit the license of the feed. If an entry has no license link relations, it does inherit the license of its parent feed(s). Since an entry may appear in Snell Expires April 4, 2007 [Page 4] Internet-Draft Feed License October 2006 multiple feeds, it may inherit multiple licenses. This is equivalent to stating multiple licenses on the entry itself. The license on an entry MAY be inherited by media resources associated with the entry. Some media types have ways of including license information, which always overrides the entry's licensing. Thus, an agent searching to find entries that fall under a specific license (e.g. search for entries containing pictures and the word "knitting" where the entry is under any Creative Commons license) MUST check the most granular license definition available, rather than assume license inheritance without checking. 2.4. Relationship with the "atom:rights" element License link relations are related to the "atom:rights" element in that both are intended to communicate information about the rights associated with an Atom document. Where the two differ, however, is in the fact that "atom:rights" is intended strictly as a human- readable assertion of rights held over a work while the license link relation is intended to provide a potentially machine-readable description of what rights have been granted to others. The two constructs may overlap one another and conflicts could arise if they are contradictory. It is important that publishers of Atom documents ensure that the "atom:rights" and license link relations are consistent with one another. 3. Security Considerations When "license" link relations are used in Atom documents, the security considerations specified in [RFC4287] Section 8 apply. 4. IANA Considerations This specification defines one new Atom link relation type to be registered in the IANA Registry of Link Relations as defined by [RFC4287]. Attribute Value: license Description: Specifies the IRI of a license associated with the containing feed, entry or source element. Expected display characteristics: None Security considerations: When "license" link relations are used in Atom documents, the security considerations for handling links in Atom documents apply. Snell Expires April 4, 2007 [Page 5] Internet-Draft Feed License October 2006 5. References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4287] Nottingham, M., Ed. and R. Sayre, Ed., "The Atom Syndication Format", RFC 4287, December 2005. Appendix A. Acknowledgements The author gratefully acknowledges the feedback from Mike Linksvayer, Robin Cover, Lisa Dussealt, Bjorn Hohrmann, Frank Ellermann, and the members of Atom Publishing Format and Protocol working group during the development of this specification. Snell Expires April 4, 2007 [Page 6] Internet-Draft Feed License October 2006 Author's Address James M Snell Phone: Email: jasnell@gmail.com URI: http://www.snellspace.com Snell Expires April 4, 2007 [Page 7] Internet-Draft Feed License October 2006 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Snell Expires April 4, 2007 [Page 8]