draft-nottingham-atompub-feed-history-08.txt		draft-nottingham-atompub-feed-history-09.txt
	Network Working Group M. Nottingham		Network Working Group M. Nottingham
	Intended status: Standards Track		Intended status: Standards Track
	Expires: May 26, 2007		Expires: October 24, 2007
	Feed Paging and Archiving		Feed Paging and Archiving
	draft-nottingham-atompub-feed-history-08		draft-nottingham-atompub-feed-history-09
	Status of This Memo		Status of This Memo
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	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (2006).		Copyright (C) The IETF Trust (2007).
	Abstract		Abstract
	This specification defines three types of syndicated Web feeds that		This specification defines three types of syndicated Web feeds that
	enable publication of entries across one or more feed documents.		enable publication of entries across one or more feed documents.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 3		1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 3
	1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Complete Feeds . . . . . . . . . . . . . . . . . . . . . . . . 4		2. Complete Feeds . . . . . . . . . . . . . . . . . . . . . . . . 4
	3. Paged Feeds . . . . . . . . . . . . . . . . . . . . . . . . . 5		3. Paged Feeds . . . . . . . . . . . . . . . . . . . . . . . . . 5
	4. Archived Feeds . . . . . . . . . . . . . . . . . . . . . . . . 6		4. Archived Feeds . . . . . . . . . . . . . . . . . . . . . . . . 6
	4.1. Publishing Archived Feeds . . . . . . . . . . . . . . . . 9		4.1. Publishing Archived Feeds . . . . . . . . . . . . . . . . 9
	4.2. Consuming Archived Feeds . . . . . . . . . . . . . . . . . 9		4.2. Consuming Archived Feeds . . . . . . . . . . . . . . . . . 9
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 10		6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10		7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
	7.1. Normative References . . . . . . . . . . . . . . . . . . . 10		7.1. Normative References . . . . . . . . . . . . . . . . . . . 11
	7.2. Informative References . . . . . . . . . . . . . . . . . . 11		7.2. Informative References . . . . . . . . . . . . . . . . . . 11
	Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 11		Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 11
	Appendix B. Use in RSS 2.0 . . . . . . . . . . . . . . . . . . . 11		Appendix B. Use in RSS 2.0 . . . . . . . . . . . . . . . . . . . 11
	1. Introduction		1. Introduction
	Syndicated Web feeds (using such formats as Atom [RFC4287]) are often		Syndicated Web feeds (using such formats as Atom [RFC4287]) are often
	split up into multiple documents to save bandwidth, allow "sliding		split up into multiple documents to save bandwidth, allow "sliding
	window" access, or for other purposes.		window" access, or for other purposes.
	This specification formalizes two types of feeds that can span one or		This specification formalizes two types of feeds that can span one or
	more feed documents; "paged" feeds and "archived" feeds.		more feed documents; "paged" feeds and "archived" feeds.
	Additionally, it defines "complete" feeds to cover the case when a		Additionally, it defines "complete" feeds to cover the case when a
	single feed document explicitly represents all of the feed's entries.		single feed document explicitly represents all of the feed's entries.
	Each has different properties and trade-offs:		Each has different properties and trade-offs:
	o Complete feeds contain the entire set of entries in one document,		o Complete feeds contain the entire set of entries in one document,
	and can be useful when it isn't desirable to "remember"		and can be useful when it isn't desirable to "remember"
	previously-seen entries.		previously-seen entries.
	o Paged feeds split the logical feed's entries among multiple		o Paged feeds split the entries among multiple temporary documents.
	temporary documents. This can be useful when entries in the feed		This can be useful when entries in the feed are not long-lived or
	are not long-lived or stable, and the client needs to access an		stable, and the client needs to access an arbitrary portion of
	arbitrary portion of them, usually in close succession.		them, usually in close succession.
	o Archived feeds split them among multiple permanent documents, and		o Archived feeds split them among multiple permanent documents, and
	can be useful when entries are long-lived and it is important for		can be useful when entries are long-lived and it is important for
	clients to see every one.		clients to see every one.
	The semantics of a feed that combines these types is undefined by		The semantics of a feed that combines these types is undefined by
	this specification.		this specification.
	Although they refer to Atom normatively, the mechanisms described		Although they refer to Atom normatively, the mechanisms described
	herein can be used with similar syndication formats; see Appendix B		herein can be used with similar syndication formats; see Appendix B
	for one such use.		for one such use.
	skipping to change at page 4, line 6		skipping to change at page 4, line 6
	"fh": "http://purl.org/syndication/history/1.0"		"fh": "http://purl.org/syndication/history/1.0"
	1.2. Terminology		1.2. Terminology
	In this specification, "feed document" refers to an Atom Feed		In this specification, "feed document" refers to an Atom Feed
	Document or similar syndication instance document. It may contain		Document or similar syndication instance document. It may contain
	any number of entries, and may or may not be a complete		any number of entries, and may or may not be a complete
	representation of the logical feed.		representation of the logical feed.
	A "logical feed" is the set of entries associated with a particular		A "logical feed" is the complete set of entries associated with a
	feed (as contrasted with a feed document, which may contain a subset		feed (as contrasted with a feed document, which may contain a subset
	of them).		of them).
	"Head section" refers to a document's feed-wide metadata container;		"Head section" refers to a document's feed-wide metadata container;
	e.g., the child elements of the atom:feed element in an Atom Feed		e.g., the child elements of the atom:feed element in an Atom Feed
	Document.		Document.
	This specification uses terms from the XML Infoset		This specification uses terms from the XML Infoset
	[W3C.REC-xml-infoset-20040204]. However, this specification uses a		[W3C.REC-xml-infoset-20040204]. However, this specification uses a
	shorthand; the phrase "Information Item" is omitted when naming		shorthand; the phrase "Information Item" is omitted when naming
	skipping to change at page 10, line 13		skipping to change at page 10, line 13
	Clients SHOULD warn users when they are not able to reconstruct the		Clients SHOULD warn users when they are not able to reconstruct the
	entire logical feed (e.g., by alerting the user that an archive		entire logical feed (e.g., by alerting the user that an archive
	document is unavailable, or displaying pseudo-entries that inform the		document is unavailable, or displaying pseudo-entries that inform the
	user that some entries may be missing).		user that some entries may be missing).
	5. IANA Considerations		5. IANA Considerations
	The "previous", "next" and "current" link relations have been		The "previous", "next" and "current" link relations have been
	previously registered, and no IANA action regarding them is required.		previously registered, and no IANA action regarding them is required.
	This specification defines the following link relations:		This specification defines the following new relations, to be added
			to the Link Relations registry:
	o Attribute Value: prev-archive		o Attribute Value: prev-archive
	o Description: A URI that refers to the immediately		o Description: A URI that refers to the immediately
	preceding archive document.		preceding archive document.
	o Expected display characteristics: none		o Expected display characteristics: none
	o Security considerations: See [ this document ]		o Security considerations: See [ this document ]
	o Attribute Value: next-archive		o Attribute Value: next-archive
	o Description: A URI that refers to the immediately		o Description: A URI that refers to the immediately
	following archive document.		following archive document.
	o Expected display characteristics: none		o Expected display characteristics: none
	o Security considerations: See [ this document ]		o Security considerations: See [ this document ]
	6. Security Considerations		6. Security Considerations
			Feeds using this mechanism have the same authentication and channel
			security concerns as explained in Atom [RFC4287].
	Feeds using these mechanisms could be crafted in such a way as to		Feeds using these mechanisms could be crafted in such a way as to
	cause a client to initiate excessive (or even an unending sequence		cause a client to initiate excessive (or even an unending sequence
	of) network requests, causing denial of service (either to the		of) network requests, causing denial of service (either to the
	client, the target server, and/or intervening networks). Clients can		client, the target server, and/or intervening networks). Clients can
	mitigate this risk by requiring user intervention after a certain		mitigate this risk by requiring user intervention after a certain
	number of requests, or by limiting requests either according to a		number of requests, or by limiting requests either according to a
	hard limit, or with heuristics.		hard limit, or with heuristics. Servers can mitigate this risk by
			denying requests that they consider abusive (e.g., by closing the
			connection, or generating an error).
	Clients should be mindful of resource limits when storing feed		Clients should be mindful of resource limits when storing feed
	documents. To reiterate, they are not required to always store or		documents. To reiterate, they are not required to always store or
	reconstruct the feed when conforming to this specification; they only		reconstruct the feed when conforming to this specification; they only
	need inform the user when the reconstructed feed is not complete.		need inform the user when the reconstructed feed is not complete.
	7. References		7. References
	7.1. Normative References		7.1. Normative References
	skipping to change at page 11, line 23		skipping to change at page 11, line 32
	W3C REC REC-xml-infoset-20040204,		W3C REC REC-xml-infoset-20040204,
	February 2004.		February 2004.
	[W3C.REC-xml-names-19990114] Bray, T., Hollander, D., and A.		[W3C.REC-xml-names-19990114] Bray, T., Hollander, D., and A.
	Layman, "Namespaces in XML", W3C		Layman, "Namespaces in XML", W3C
	REC REC-xml-names-19990114,		REC REC-xml-names-19990114,
	January 1999.		January 1999.
	7.2. Informative References		7.2. Informative References
	[RSS2] Winer, D., "RSS 2.0 Specification", 2005,		[RSS2] Winer, D., "RSS 2.0 Specification",
	<http://blogs.law.harvard.edu/tech/rss>.		2005, <http://blogs.law.harvard.edu/
			tech/rss>.
	Appendix A. Acknowledgements		Appendix A. Acknowledgements
	The author would like to thank the following people for their		The author would like to thank the following people for their
	contributions, comments and help: Danny Ayers, Thomas Broyer, Lisa		contributions, comments and help: Danny Ayers, Thomas Broyer, Lisa
	Dusseault, Stefan Eissing, David Hall, Bill de Hora, Aristotle		Dusseault, Stefan Eissing, David Hall, Bill de Hora, Vidya Narayanan,
	Pagaltzis, John Panzer, Dave Pawson, Garrett Rooney, Robert Sayre,		Aristotle Pagaltzis, John Panzer, Dave Pawson, Garrett Rooney, Robert
	James Snell, Henry Story.		Sayre, James Snell, Henry Story.
	Any errors herein remain the author's, not theirs.		Any errors herein remain the author's, not theirs.
	Appendix B. Use in RSS 2.0		Appendix B. Use in RSS 2.0
	As previously noted, while this specification's extensions are		As previously noted, while this specification's extensions are
	described in terms of the Atom feed format, they are also useful in		described in terms of the Atom feed format, they are also useful in
	similar formats. This informative appendix demonstrates how they can		similar formats. This informative appendix demonstrates how they can
	be used in an RSS 2.0-formatted [RSS2] feed.		be used in an RSS 2.0-formatted [RSS2] feed.
	skipping to change at page 17, line 7		skipping to change at page 17, line 7
	Author's Address		Author's Address
	Mark Nottingham		Mark Nottingham
	EMail: mnot@pobox.com		EMail: mnot@pobox.com
	URI: http://www.mnot.net/		URI: http://www.mnot.net/
	Full Copyright Statement		Full Copyright Statement
	Copyright (C) The Internet Society (2006).		Copyright (C) The IETF Trust (2007).
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	retain all their rights.		retain all their rights.
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	Intellectual Property		Intellectual Property
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