Network Working Group J. Snell
Internet-Draft November 2005
Expires: May 5, 2006
Atom Syndication Format Tombstones
draft-snell-atompub-tombstones-00.txt
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Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
This specification defines mechanisms by which Atom Feed publishers
may explicitly indicate that specific Atom Entries have been deleted
or archived.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3
3. The 'deleted-entry' element . . . . . . . . . . . . . . . . . . 3
4. The 'archived-entry' element . . . . . . . . . . . . . . . . . 4
5. The 'by' Element . . . . . . . . . . . . . . . . . . . . . . . 6
6. The 'comment' Element . . . . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8
Intellectual Property and Copyright Statements . . . . . . . . . . 9
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1. Introduction
This specification defines mechanisms in the form of Atom Format
[RFC4287] extensions that Atom Feed publishers can use to explicitly
indicate that specific Atom Entries have been removed from a feed due
to deletion or archiving.
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-19990114]
to uniquely identify XML element names. It uses the following
namespace prefix for the indicated namespace URI;
{Ed. Note: this namespace MUST be changed to a proper IETF namespace
scheme prior to publication}
"at": "http://purl.org/atompub/tombstones/1.0"
3. The 'deleted-entry' element
The 'deleted-entry' element MAY appear as a child of atom:feed to
represent an Atom Entry that has been removed from the feed due to
deletion. The element consists of a required 'id' attribute whose
value specifies the universally unique atom:id value of the deleted
entry and an optional 'when' attribute whose value is an Atom Date
Construct specifying the instant the entry was deleted.
deletedEntry = element at:deleted-entry {
atomCommonAttributes,
& attribute id { atomURI },
& attribute when { atomDateConstruct }?,
( by?,
& comment*,
& undefinedContent )
}
Atom Processors MUST ignore 'deleted-entry' elements whose 'id'
attributes reference Atom Entries that have not previously appeared
within the Atom Feed document.
The 'deleted-entry' element MAY contain a 'by' element that
identifies the entity that deleted the entry.
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The 'deleted-entry' element MAY contain zero or more 'comment'
elements whose content provides additional information about the
deletion operation.
Atom Feed Documents MAY contain any number of 'deleted-entry'
elements.
...
John Doe
jdoe@example.org
Removed comment spam
John Doe
jdoe@example.org
Removed comment spam
...
4. The 'archived-entry' element
The 'archived-entry' element MAY appear as a child of atom:feed to
represent an Atom Entry that has been removed from the feed due to
archiving. The element consists of a required 'id' attrubute whose
value specifies the universally unique atom:id value of the archived
entry, a required 'href' attribute whose value specifies the IRI from
which the archived Atom Entry Document MAY be retrieved, and an
optional 'when' attribute whose value is an Atom Date Construct
specifying the instant the entry was archived.
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archivedEntry = element at:archived-entry {
atomCommonAttributes,
& attribute id { atomURI },
& attribute href { atomURI },
& attribute when { atomDateConstruct }?,
( by?,
& comment*,
& undefinedContent )
}
The 'archived-entry' element MAY contain a 'by' element that
identifies the entity that archived the entry.
The 'archived-entry' element MAY contain zero or more 'comment'
elements whose content provides additional information about the
archival operation.
Atom Processors MUST ignore 'archived-entry' elements whose 'id'
attributes reference Atom Entries that have not previously appeared
within the Atom Feed document.
Atom Feed Documents MAY contain any number of 'archived-entry'
elements.
...
Automated Archive Process
Automated Archive Process
...
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5. The 'by' Element
The 'by' element is an Atom Person Construct that is used to identify
the entity that performed a deletion or archive operation on an
entry.
by = element at:by { atomPersonConstruct }
6. The 'comment' Element
The 'comment' element in an Atom Text Construct that is used to
provide additional human readable information about a deletion or
archive operation on an entry.
comment = element at:comment { atomTextConstruct }
7. Security Considerations
As specified in [RFC4287], Atom processors should be aware of the
potential for spoofing attacks where an attacked publishes atom:entry
elements with the same atom:id value of entries from other Atom
feeds. The same potential exists with the mechanisms defined here in
that an attacker may attempt to spoof an application into believing
that a given entry has been removed from a feed. To mitigate this
issue, Atom processors MUST ignore 'deleted-entry' and 'archived-
entry' elements referencing entries that have not previously appeared
within the containing Feed document and should take steps to verify
the origin of the Atom feed before considering the entries to be
removed.
8. IANA Considerations
There are no IANA considerations introduced by this specification.
9. Acknowledgements
The author gratefully acknowledges the feedback from the members of
the Atom Publishing Format and Protocol working group during the
development of this specification.
10. References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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[RFC4287] Nottingham, M. and R. Sayre, "The Atom Syndication
Format", RFC 4287, December 2005.
[W3C.REC-xml-infoset-20040204]
Tobin, R. and J. Cowan, "XML Information Set (Second
Edition)", W3C REC REC-xml-infoset-20040204,
February 2004.
[W3C.REC-xml-names-19990114]
Hollander, D., Bray, T., and A. Layman, "Namespaces in
XML", W3C REC REC-xml-names-19990114, January 1999.
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Author's Address
James M Snell
Phone:
Email: jasnell@gmail.com
URI: http://snellspace.com
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