Network Working Group J. Snell
Internet-Draft October 22, 2007
Intended status: Experimental
Expires: April 24, 2008
Atom Publishing Protocol Feature Discovery
draft-snell-atompub-feature-11.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 24, 2008.
Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
This document introduces extensions to the Atom Publishing Protocol
Service Document format for expressing metadata about the behaviors,
functions and capabilities supported by an Atom Publishing Protocol
collection.
Snell Expires April 24, 2008 [Page 1]
Internet-Draft Atompub Features October 2007
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
3. The f:feature element . . . . . . . . . . . . . . . . . . . . . 4
3.1. Example . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. The "supportsDraft" Feature . . . . . . . . . . . . . . . . . . 6
5. The "ignoresDraft" Feature . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
8. Normative References . . . . . . . . . . . . . . . . . . . . . 6
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7
Intellectual Property and Copyright Statements . . . . . . . . . . 8
Snell Expires April 24, 2008 [Page 2]
Internet-Draft Atompub Features October 2007
1. Introduction
This document introduces an extension to the Atom Publishing Protocol
(Atompub) service document [RFC5023] format that allows for the
documentation and discovery of behaviors, functions or capabilities
supported by an Atompub collection. Examples of such capabilities
can include the preservation of certain kinds of content, support for
draft entries, support for the scheduled publication of entries, use
of a particular set of Atom format extensions, and so on.
Describing features using the mechanisms defined in this
specification is currently considered to be largely experimental.
While there are examples of such mechanisms being put to practical
use in deployed applications, there is currently not enough
collective implementation experience to determine whether the
mechanism defined here is sufficient to fully address the general
needs of Atom Publishing Protocol client and server implementations.
Implementations and feedback are encouraged.
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].
This specification uses XML Namespaces [W3C.REC-xml-names-20060816]
to uniquely identify XML element names. It uses the following
namespace prefix for the indicated namespace URI;
"f": "http://purl.org/atompub/features/1.0"
This specification uses terms from the XML Infoset
[W3C.REC-xml-infoset-20040204]. However, this specification uses a
shorthand; the phrase "Information Item" is omitted when naming
Element Information Items. Therefore, when this specification uses
the terms "element" and "attribute" it is referring, respectively, to
the Element and Attribute Information Items in Infoset terms.
This specification uses the terms "atomUri" and
"atomCommonAttributes" from the non-normative RELAX NG Compact schema
included in [RFC4287]. Where used, these serve the same purpose and
have the same meaning as their use in [RFC4287].
Atom allows the use of IRIs [RFC3987]. Every URI [RFC3986] is also
an IRI, so a URI may be used wherever below an IRI is named. There
are two special considerations: (1) when an IRI that is not also a
URI is given for dereferencing, it MUST be mapped to a URI using the
Snell Expires April 24, 2008 [Page 3]
Internet-Draft Atompub Features October 2007
steps in Section 3.1 of [RFC3987] and (2) when an IRI is serving as
an identifier, it MUST NOT be so mapped.
Any element defined by this specification MAY have an xml:base
attribute [W3C.REC-xmlbase-20010627]. When xml:base is used, it
serves the function described in section 5.1.1 of [RFC3986],
establishing the base URI (or IRI) for resolving any relative
references found within the effective scope of the xml:base
attribute.
Any element defined by this specification MAY have an xml:lang
attribute, whose content indicates the natural language for the
element and its descendents. The language context is only
significant for elements and attributes declared to be "Language-
Sensitive". Requirements regarding the content and interpretation of
xml:lang are specified in XML 1.0 [W3C.REC-xml-20060816], Section
2.12.
3. The f:feature element
The f:feature element is used in an app:collection element to declare
the collection's support for a feature.
namespace f = "http://purl.org/atompub/features/1.0"
feature = element f:feature {
atomCommonAttributes,
attribute ref { atomUri },
attribute href { atomUri }?,
attribute label { text }?,
(anyElement)*
}
anyElement = element * - f:feature {
(attribute * { text }
| text
| anyElement)*
}
The ref attribute specifies a globally unique IRI identifying a
feature. The value of the ref attribute MUST be compared on a case-
sensitive, character-by-character basis. Relative references MUST
NOT be used. The IRI is used strictly for identification and cannot
be assumed to be dereferenceable.
An optional href attribute MAY be used to specify a dereferenceable
IRI of a human-readable description of the feature. Relative
Snell Expires April 24, 2008 [Page 4]
Internet-Draft Atompub Features October 2007
references MAY be used.
The optional label attribute MAY be used to specify a human-readable
label for the feature. The value of the label attribute is Language-
Sensitive as defined by Section 2 of [RFC4287].
The f:feature element MAY contain a mix of text and any number of
child elements and attributes from any XML namespace, with the
exception of the f:feature element itself. Such markup is considered
to be metadata applicable to the feature identified. Software agents
MUST NOT stop processing or signal an error or change their behavior
as a result of encountering such markup.
An app:collection element MAY contain any number of f:feature
elements but MUST NOT contain more than one with the same ref
attribute value. The order in which f:feature elements appear within
the app:collection element is insignificant.
The presence of a f:feature element is an indication that the
collection supports the feature identified. The lack of a f:feature
element identifying a particular feature indicates that support for
that feature is unspecified. This does not mean that the feature is
not supported, only that the server has not explicitly declared
support. There are no means by which a server can indicate that a
given feature is unsupported.
3.1. Example
The following is an example of a collection using the f:feature
element to indicate its support for the app:draft element as defined
by [RFC5023].
<service
xmlns="http://www.w3.org/2007/app"
xmlns:atom="http://www.w3.org/2005/Atom"
xmlns:f="http://purl.org/atompub/features/1.0">
<workspace>
<atom:title>My Workspace</atom:title>
<collection href="...">
<atom:title>My Atom Collection</atom:title>
<accept>application/atom+xml;type=entry</accept>
<f:feature
ref="http://purl.org/atompub/features/1.0/supportsDraft" />
</collection>
</workspace>
</service>
Snell Expires April 24, 2008 [Page 5]
Internet-Draft Atompub Features October 2007
4. The "supportsDraft" Feature
The "supportsDraft" feature is used to indicate that a collection
supports the use of the app:draft control element as defined by
Section 13.1.1 of [RFC5023]. The IRI of the "supportsDraft" feature
is:
http://purl.org/atompub/features/1.0/supportsDraft
5. The "ignoresDraft" Feature
The "ignoresDraft" feature is used to indicate that a collection will
ignore the use of the app:draft control element as defined by Section
13.1.1 of [RFC5023]. The IRI of the "ignoresDraft" feature is:
http://purl.org/atompub/features/1.0/ignoresDraft
A server MUST NOT declare support for both the "supportsDraft" and
"ignoresDraft" features within the a single app:collection element.
6. Security Considerations
Specific features supported by a collection may introduce security
considerations and concerns beyond those discussed by the Atom
Publishing Protocol and Atom Syndication Format specifications.
Implementors must refer to the specifications and description of each
feature to determine the security considerations relevant to each.
7. IANA Considerations
This specification does not define any actions for IANA.
8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource
Identifiers (IRIs)", RFC 3987, January 2005.
[RFC4287] Nottingham, M., Ed. and R. Sayre, Ed., "The Atom
Syndication Format", RFC 4287, December 2005.
Snell Expires April 24, 2008 [Page 6]
Internet-Draft Atompub Features October 2007
[RFC5023] Gregorio, J. and B. de hOra, "The Atom Publishing
Protocol", RFC 5023, October 2007.
[W3C.REC-xml-20060816]
Bray, T., Paoli, J., Yergeau, F., Sperberg-McQueen, C.,
and E. Maler, "Extensible Markup Language (XML) 1.0
(Fourth Edition)", World Wide Web Consortium
Recommendation REC-xml-20060816, August 2006,
<http://www.w3.org/TR/2006/REC-xml-20060816>.
[W3C.REC-xml-infoset-20040204]
Tobin, R. and J. Cowan, "XML Information Set (Second
Edition)", World Wide Web Consortium Recommendation REC-
xml-infoset-20040204, February 2004,
<http://www.w3.org/TR/2004/REC-xml-infoset-20040204>.
[W3C.REC-xml-names-20060816]
Hollander, D., Tobin, R., Bray, T., and A. Layman,
"Namespaces in XML 1.0 (Second Edition)", World Wide Web
Consortium Recommendation REC-xml-names-20060816,
August 2006,
<http://www.w3.org/TR/2006/REC-xml-names-20060816>.
[W3C.REC-xmlbase-20010627]
Marsh, J., "XML Base", World Wide Web Consortium
Recommendation REC-xmlbase-20010627, June 2001,
<http://www.w3.org/TR/2001/REC-xmlbase-20010627>.
Appendix A. Acknowledgements
The author acknowledges the feedback from the other members of the
IETF Atom Publishing working group during the development of this
specification.
Author's Address
James M Snell
Phone:
Email: jasnell@gmail.com
URI: http://snellspace.com
Snell Expires April 24, 2008 [Page 7]
Internet-Draft Atompub Features October 2007
Full Copyright Statement
Copyright (C) The IETF Trust (2007).
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.
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, THE IETF TRUST 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.
Intellectual Property
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.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
Snell Expires April 24, 2008 [Page 8]
