draft-gregorio-09.txt		draft-ietf-atompub-protocol-00.txt
	yes J. Gregorio		Network Working Group J. Gregorio, Ed.
	BitWorking, Inc		Internet-Draft BitWorking, Inc
	December 10, 2003		Expires: December 30, 2004 R. Sayre, Ed.
			Boswijck Memex Consulting
			July 1, 2004
	The AtomAPI		The Atom Publishing Protocol
			draft-ietf-atompub-protocol-00.txt
	Abstract		Status of this Memo
	This memo presents a technique for using XML (Extensible Markup		By submitting this Internet-Draft, I certify that any applicable
	Language) and HTTP (HyperText Transport Protocol) to edit content.		patent or other IPR claims of which I am aware have been disclosed,
			and any of which I become aware will be disclosed, in accordance with
			RFC 3668.
	Table of Contents		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.
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 3		Internet-Drafts are draft documents valid for a maximum of six months
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4		and may be updated, replaced, or obsoleted by other documents at any
	3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 5		time. It is inappropriate to use Internet-Drafts as reference
	4. Introduction . . . . . . . . . . . . . . . . . . . . . . . 6		material or to cite them other than as "work in progress."
	4.1 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . 6
	4.2 Terminology . . . . . . . . . . . . . . . . . . . . . . . 6
	4.3 The AtomAPI Model . . . . . . . . . . . . . . . . . . . . 6
	5. Functional Specification . . . . . . . . . . . . . . . . . 8
	5.1 PostURI . . . . . . . . . . . . . . . . . . . . . . . . . 8
	5.1.1 Locating . . . . . . . . . . . . . . . . . . . . . . . . . 8
	5.1.2 Request . . . . . . . . . . . . . . . . . . . . . . . . . 8
	5.1.3 Response . . . . . . . . . . . . . . . . . . . . . . . . . 8
	5.2 EditURI . . . . . . . . . . . . . . . . . . . . . . . . . 9
	5.2.1 Locating . . . . . . . . . . . . . . . . . . . . . . . . . 9
	5.2.2 Request . . . . . . . . . . . . . . . . . . . . . . . . . 10
	5.3 FeedURI . . . . . . . . . . . . . . . . . . . . . . . . . 10
	5.3.1 Locating . . . . . . . . . . . . . . . . . . . . . . . . . 10
	5.3.2 Request . . . . . . . . . . . . . . . . . . . . . . . . . 11
	5.3.3 Response . . . . . . . . . . . . . . . . . . . . . . . . . 11
	5.4 Link Tag . . . . . . . . . . . . . . . . . . . . . . . . . 11
	5.4.1 rel . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
	5.4.2 href . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
	5.4.3 title . . . . . . . . . . . . . . . . . . . . . . . . . . 12
	5.4.4 type . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
	5.5 Atom Request and Response Body Constraints . . . . . . . . 12
	5.5.1 id . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
	5.5.2 link . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
	5.5.3 title . . . . . . . . . . . . . . . . . . . . . . . . . . 13
	5.5.4 summary . . . . . . . . . . . . . . . . . . . . . . . . . 13
	5.5.5 content . . . . . . . . . . . . . . . . . . . . . . . . . 14
	5.5.6 issued . . . . . . . . . . . . . . . . . . . . . . . . . . 14
	5.5.7 modified . . . . . . . . . . . . . . . . . . . . . . . . . 15
	5.5.8 created . . . . . . . . . . . . . . . . . . . . . . . . . 15
	5.5.9 author . . . . . . . . . . . . . . . . . . . . . . . . . . 15
	The AtomAPI December 2003
	5.5.10 contributor . . . . . . . . . . . . . . . . . . . . . . . 16		The list of current Internet-Drafts can be accessed at
	5.5.11 generator . . . . . . . . . . . . . . . . . . . . . . . . 16		http://www.ietf.org/ietf/1id-abstracts.txt.
	6. Security Considerations . . . . . . . . . . . . . . . . . 17
	7. Appendices . . . . . . . . . . . . . . . . . . . . . . . . 18
	7.1 SOAP Enabling . . . . . . . . . . . . . . . . . . . . . . 18
	7.1.1 Servers . . . . . . . . . . . . . . . . . . . . . . . . . 18
	7.1.2 Clients . . . . . . . . . . . . . . . . . . . . . . . . . 18
	7.2 Example for a weblog . . . . . . . . . . . . . . . . . . . 18
	7.3 Example for a wiki . . . . . . . . . . . . . . . . . . . . 19
	8. Revision History . . . . . . . . . . . . . . . . . . . . . 20
	9. Copyright . . . . . . . . . . . . . . . . . . . . . . . . 21
	References . . . . . . . . . . . . . . . . . . . . . . . . 22
	Author's Address . . . . . . . . . . . . . . . . . . . . . 22
	The AtomAPI December 2003
	1. Introduction		The list of Internet-Draft Shadow Directories can be accessed at
			http://www.ietf.org/shadow.html.
	The AtomAPI is an application level protocol for publishing and		This Internet-Draft will expire on December 30, 2004.
	editing web resources. The protocol at its core is the HTTP transport
	of Atom formatted representations.
	To provide feedback on this draft RFC please visit the Atom Wiki [1]		Copyright Notice
	or join the atom-syntax mailing list [2].
	The AtomAPI December 2003		Copyright (C) The Internet Society (2004). All Rights Reserved.
	2. Terminology		Abstract
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		This memo presents a protocol for using XML (Extensible Markup
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",the and "OPTIONAL" in		Language) and HTTP (HyperText Transport Protocol) to edit content.
	this document are to be interpreted as described in RFC2119.
	The AtomAPI December 2003		The Atom Publishing Protocol is an application-level protocol for
			publishing and editing Web resources belonging to periodically
			updated websites. The protocol at its core is the HTTP transport of
			Atom-formatted representations. The Atom format is documented in the
			Atom Syndication Format 0.3 PRE-DRAFT
			(http://www.mnot.net/drafts/draft-nottingham-atom-format-02.html).
	3. Scope		To provide feedback on this Internet-Draft, join the atom-syntax
			mailing list (http://www.imc.org/atom-syntax/index.html).
	This document covers the editing of content of a periodically		Table of Contents
	updating website using the HTTP and XML. All of the XML payloads are
	in Atom format, which is documented in the draft Atom Syndication
	Format RFC [3].
	The AtomAPI December 2003		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
			1.1 Notational Conventions . . . . . . . . . . . . . . . . . . 4
			1.2 Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
			2. The Atom Publishing Protocol Model . . . . . . . . . . . . . 4
			3. Functional Specification . . . . . . . . . . . . . . . . . . 5
			3.1 PostURI . . . . . . . . . . . . . . . . . . . . . . . . . 5
			3.1.1 Locating the PostURI . . . . . . . . . . . . . . . . . 5
			3.1.2 Request . . . . . . . . . . . . . . . . . . . . . . . 5
			3.1.3 Response . . . . . . . . . . . . . . . . . . . . . . . 5
			3.2 EditURI . . . . . . . . . . . . . . . . . . . . . . . . . 6
			3.2.1 Locating . . . . . . . . . . . . . . . . . . . . . . . 7
			3.2.2 Request . . . . . . . . . . . . . . . . . . . . . . . 7
			3.3 FeedURI . . . . . . . . . . . . . . . . . . . . . . . . . 7
			3.3.1 Locating . . . . . . . . . . . . . . . . . . . . . . . 8
			3.3.2 Request . . . . . . . . . . . . . . . . . . . . . . . 8
			3.3.3 Response . . . . . . . . . . . . . . . . . . . . . . . 8
			3.4 Link Tag . . . . . . . . . . . . . . . . . . . . . . . . . 8
			3.4.1 rel . . . . . . . . . . . . . . . . . . . . . . . . . 8
			3.4.2 href . . . . . . . . . . . . . . . . . . . . . . . . . 9
			3.4.3 title . . . . . . . . . . . . . . . . . . . . . . . . 9
			3.4.4 type . . . . . . . . . . . . . . . . . . . . . . . . . 9
			3.5 Atom Request and Response Body Constraints . . . . . . . . 9
			3.5.1 id . . . . . . . . . . . . . . . . . . . . . . . . . . 9
			3.5.2 link . . . . . . . . . . . . . . . . . . . . . . . . . 10
			3.5.3 title . . . . . . . . . . . . . . . . . . . . . . . . 10
			3.5.4 summary . . . . . . . . . . . . . . . . . . . . . . . 10
			3.5.5 content . . . . . . . . . . . . . . . . . . . . . . . 10
			3.5.6 issued . . . . . . . . . . . . . . . . . . . . . . . . 11
			3.5.7 modified . . . . . . . . . . . . . . . . . . . . . . . 11
			3.5.8 created . . . . . . . . . . . . . . . . . . . . . . . 11
			3.5.9 author . . . . . . . . . . . . . . . . . . . . . . . . 11
			3.5.10 contributor . . . . . . . . . . . . . . . . . . . . 12
			3.5.11 generator . . . . . . . . . . . . . . . . . . . . . 12
			4. Security Considerations . . . . . . . . . . . . . . . . . . 12
			5. IANA Considerations . . . . . . . . . . . . . . . . . . . . 13
			6. Appendix A - SOAP Enabling . . . . . . . . . . . . . . . . . 13
			6.1 Servers . . . . . . . . . . . . . . . . . . . . . . . . . 13
			6.2 Clients . . . . . . . . . . . . . . . . . . . . . . . . . 13
			7. Appendix B - Examples . . . . . . . . . . . . . . . . . . . 13
			7.1 Example for a weblog . . . . . . . . . . . . . . . . . . . 13
			7.2 Example for a wiki . . . . . . . . . . . . . . . . . . . . 13
			8. Revision History . . . . . . . . . . . . . . . . . . . . . . 14
			9. Normative References . . . . . . . . . . . . . . . . . . . . 15
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 15
			Intellectual Property and Copyright Statements . . . . . . . 16
	4. Introduction		1. Introduction
	4.1 Purpose		The Atom Publishing Protocol is an application-level protocol for
			publishing and editing Web resources.
	The AtomAPI is an application level protocol for publishing and		1.1 Notational Conventions
	editing web resources.
	4.2 Terminology		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
			"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", the and "OPTIONAL" in
			this document are to be interpreted as described in RFC2119.
	Atom Entry A fragment of a full Atom feed. In this case the fragment		1.2 Terminology
	is a single 'entry' element and all it's child elements.
	PostURI A URI that is used to create new resources. POSTing an Atom		Atom Entry: An Atom Entry is a fragment of a full Atom feed. In this
			case, the fragment is a single 'entry' element and all its child
			elements. Each Atom Entry describes a single Web resource,
			providing metadata and optionally a textual representation of that
			resource.
			PostURI: A URI that is used to create new resources. POSTing an Atom
	Entry to this URI will create a new resource.		Entry to this URI will create a new resource.
			EditURI: A URI that is used to edit a resource. The editing is done
	EditURI A URI that is used to edit a resource. The editing is done
	using the HTTP verbs GET, PUT and DELETE. The representation of		using the HTTP verbs GET, PUT and DELETE. The representation of
	the resource is always that of an Atom Entry.		the resource is always that of an Atom Entry.
			FeedURI: The URI which identifies an Atom Feed.
	FeedURI A URI that has a representation as a full Atom feed.		2. The Atom Publishing Protocol Model
	4.3 The AtomAPI Model
	AtomAPI is an application level protocol for publishing and editing
	web resources. Using the common HTTP verbs provides a pattern for
	working with all such web resources:
			The Atom Publishing Protocol is an application-level protocol for
			publishing and editing Web resources. Using the common HTTP verbs
			provides a pattern for working with all such Web resources:
	o GET is used to retrieve a representation of a resource or perform		o GET is used to retrieve a representation of a resource or perform
	a read-only query.		a read-only query.
	o PUT is used to update a known resource.		o PUT is used to update a known resource.
	o POST is used to create a new dynamically-named resource.		o POST is used to create a new dynamically-named resource.
	o DELETE is used to remove a resource.		o DELETE is used to remove a resource.
	There are different kinds of resources managed by the AtomAPI, each		There are three major classes of URIs in this specification: PostURI,
	of these have URIs and those URIs support a subset of the above		FeedURI and EditURI. This specification defines the expected actions
	methods. There are three major classes of URIs in this specification:		for each of the methods listed. A URI MAY support methods not listed
	PostURI, FeedURI and EditURI. This specification defines the expected		here. For example, an EditURI could support a POST or OPTIONS
	actions for each of the methods listed. Note that this does not		method. However, what those methods do is beyond the scope of this
	restrict a URI to only supporting just those methods listed, for
	example an EditURI could support a POST method, or the OPTIONS
	method, what those methods do is beyond the scope of this
	specification.		specification.
	o EditURI: PUT, GET, DELETE		o EditURI: PUT, GET, DELETE
	The AtomAPI December 2003
	o PostURI: POST		o PostURI: POST
	o FeedURI: GET		o FeedURI: GET
	This RFC does not specify the form of the URIs that are used. The URI		This document does not specify the form of the URIs that are used.
	space of each server is controlled, as defined by HTTP, by the server		The URI space of each server is controlled, as defined by HTTP, by
	alone. What this RFC does specify are the formats of the files that		the server alone. What this document does specify are the formats of
	are exchanged and the actions that can be performed on the URIs		the files that are exchanged and the actions that can be performed on
	embedded in those files.		the URIs embedded in those files.
	The AtomAPI December 2003
	5. Functional Specification		3. Functional Specification
	5.1 PostURI		3.1 PostURI
	The PostURI is used to create entries. These can be either full		The PostURI is used to create entries. These can be either full
	entries, such as a weblog post, or they can be comments, or even a		entries, such as a weblog post, or they can be comments, or even a
	wiki page. The client POSTs a filled in Atom Entry to this URI. If		wiki page. The client POSTs a filled-in Atom Entry to this URI. If
	the request is succesful then multiple new URIs may be created that		the request is successful, one or more Web resources MAY be created.
	contain representations of varying types. For example, POSTing an		For example, POSTing an Atom entry to a PostURI may create two new
	Atom entry to a PostURI may create a new weblog entry with both an		Web resources, an HTML representation and an Atom representation.
	HTML and Atom representation now available. The URI of the newly
	created Atom representation may in fact be an EditURI through which
	the resource can be edited.
	5.1.1 Locating		3.1.1 Locating the PostURI
	For creating a new site Entry, the link tag is used. Note that a link		The PostURI can be discovered in a link element with an @rel of
	tag is used in both HTML and in the Atom format. A link tag of the		'service.post'. The link element containing a PostURI used to create
	following format points to the PostURI for a site. In HTML the link		a new entry MAY be discovered in three different places. The first
	tags are always found in the head element, while in Atom they may		place it may be found is in a <link> element in the 'head' element of
	appear as children of the Feed and entry elements.		an HTML document.
			The second place a PostURI may be found an atom:link element that is
			a child of the atom:feed element. The third place a PostURI may be
			found is in the atom:link element of an atom:entry.
			@@ TBD @@ - Discuss subordinate resources and what a PostURI means
			based on where the URI was found.
	<link rel="service.post"		<link rel="service.post"
	type="application/x.atom+xml"		type="application/atom+xml"
	href="URI for Posting goes here"		href="URI for Posting goes here"
	title="The name of the site.">		title="The name of the site.">
	Note: Multiple link tags may appear together and can be distinguished		3.1.2 Request
	by having different 'rel', 'type' and 'title' attributes.
	5.1.2 Request
	The request contains a filled in Atom entry, subject to the		The request contains a filled-in Atom entry, subject to the
	constraints in section @@ TBD @@.		constraints in section Section 3.5.
	5.1.3 Response		3.1.3 Response
	The expected status codes from a POST are 201, 303, 400, and 500.		The possible status codes from a POST are 201, 303, 400, 401, 404,
	401, 404, and 410 are also possible.		410 and 500.
	5.1.3.1 201		3.1.3.1 Response code 201
	Response includes a Location: header with the URI of the created		Response includes a Location: header with the URI of the created
	resource, i.e. the URI used to edit the entry, as opposed to the URI		resource, i.e. the URI used to edit the entry, as opposed to the URI
	used to display the content. The body of the response will contain		used to display the content. The body of the response will contain
	the entry "filled in" with time stamps and any other data the server		the entry "filled-in" with time stamps and any other data the server
	choses to reveal. This must contain enough information to enable a		chooses to reveal. This must contain enough information to enable a
	client to issue a subsequent PUT to this location. Note that the		client to issue a subsequent PUT to this location. Note that the
	The AtomAPI December 2003
	server may chose to omit the content in the response, particularly if		server may chose to omit the content in the response, particularly if
	it is large.		it is large.
	5.1.3.2 303		3.1.3.2 Response code 303
	The body of this response does not contain the filled in Entry, but		The body of this response does not contain the filled-in Entry, but
	the filled in Entry can be found under a different URI and SHOULD be		the filled-in Entry can be found under a different URI and can be
	retrieved using a GET method on that resource. The different URI		retrieved using a GET method on that resource. The URI SHOULD be
	SHOULD be given by the Location field in the response.		given by the Location field in the response.
	5.1.3.3 400		3.1.3.3 Response code 400
	Indicates that the server believes that that data sent constitutes an		Indicates that the server believes that that data sent constitutes an
	invalid request. A short description of the error will appear on the		invalid request. A short description of the error will appear on the
	status line itself. A longer description will appear in the body.		<http://www.w3.org/Protocols/rfc2616/rfc2616-sec6.html#sec6.1>
			itself. A longer description will appear in the body.
	5.1.3.4 500		3.1.3.4 Response code 500
	Indicates that the server detected an internal error on the server		Indicates that the server detected an internal error on the server
	processing this request (such as an unhandled exception). A short		processing this request (such as an unhandled exception). A short
	description of the error will appear on the status line itself. A		description of the error will appear on the
	longer description will appear in the body.		<http://www.w3.org/Protocols/rfc2616/rfc2616-sec6.html#sec6.1>
			itself. A longer description will appear in the body.
	5.2 EditURI		3.2 EditURI
	An EditURI is used to edit a single entry. Each entry that is		An EditURI is used to edit a single entry. Each entry that is
	editable MUST have a unique URI. This URI supports both GET and PUT		editable MUST have a unique URI. This URI supports both GET and PUT
	and they are used in tandem for an editing cycle. The client GET's		and they are used in tandem for an editing cycle. The client GETs
	the represenation which is formatted as an Atom entry. The client may		the representation which is formatted as an Atom entry. The client
	then update the entry and then PUT it back to the same URI. The PUT		may then update the entry and then PUT it back to the same URI. The
	will cause all the related resources to be updated, for example, the		PUT will cause all the related resources to be updated, for example,
	HTML representaion.		the HTML representation.
	Note that the value of the content element in the Atom entry does not		Note that the value of the content element in the Atom entry does not
	have to exactly match the content element for the same entry when it		have to exactly match the content element for the same entry when it
	is represented in an Atom feed. For example, a server may allow the		is represented in an Atom feed. For example, a server may allow the
	client to post entries whose content is formatted as WikiML, yet the		client to post entries whose content is formatted as WikiML, yet the
	server may clean up such markup and transform it into well-formed		server may clean up such markup and transform it into well-formed
	XHTML before placing it in the publicly avialable Atom feed. Another		XHTML before placing it in the publicly available Atom feed. Another
	scenario is summaries, the EditURI is for editing the full content of		scenario is summaries--the EditURI is for editing the full content of
	an entry, but the server may only present excerpts when it produces		an entry, but the server may only present excerpts when it produces
	an Atom feed.		an Atom feed.
	A client will send a DELETE to the EditURI to delete an entry.		A client will send a DELETE to the EditURI to delete an entry.
	5.2.1 Locating		3.2.1 Locating
	For editing a site Entry, the link tag is used. Note that a link tag		For editing a site Entry, the link tag is used. Note that a link tag
	The AtomAPI December 2003
	is used in both HTML and in the Atom format. A link tag of the		is used in both HTML and in the Atom format. A link tag of the
	following format points to the EditURI for a site. In HTML the link		following format points to the EditURI for a site. In HTML, the link
	tags for editing are always found in the head element, while in Atom		tags for editing are always found in the head element, while in Atom
	they may appear as children of the entry elements.		they may appear as children of the entry elements.
	<link rel="service.edit"		<link rel="service.edit"
	type="application/x.atom+xml"		type="application/atom+xml"
	href="URI for Editing goes here"		href="URI for Editing goes here"
	title="Readable desc of the entry.">		title="Readable desc of the entry.">
	Note: The critical characteristic of this link tag is the @rel of		Note: The critical characteristic of this link tag is the @rel of
	'service.edit' and the @type of 'application/x.atom+xml'.		'service.edit' and the @type of 'application/atom+xml'.
	5.2.2 Request		3.2.2 Request
	A PUT request, and a GET response both contain a filled in Atom		A PUT request, and a GET response both contain a filled-in Atom
	entry, subject to the constraints in section @@ TBD @@.		entry, subject to the constraints in section Section 3.5.
	5.3 FeedURI		3.3 FeedURI
	The FeedURI is used to retrieve a represenation in Atom format. Note		The FeedURI is used to retrieve a representation in Atom format.
	that this feed is different from a typical Atom feed in that it		Note that this feed is different from a typical Atom feed in that it
	contains "link" elements for navigating and manipulating the content		contains "link" elements for navigating and manipulating the content
	of the site. For example there should be a "link" element with		of the site. For example there should be a "link" element with
	rel="next" whose URI points to the next block of entries on the site.		rel="next" whose URI points to the next block of entries on the site.
	Similarly the feed element can contain a "link" element with		Similarly, the feed element can contain a "link" element with
	rel="service.post", the URI of which is a PostURI. Individual entries		rel="service.post", the URI of which is a PostURI. Individual
	should contain "link" elements with rel="service.edit" whose URIs are		entries should contain "link" elements with rel="service.edit" whose
	EditURIs.		URIs are EditURIs.
	@@ Editor's Note: @@ Note that the "service.feed" takes the place of		@@ Editor's Note: @@ Note that the "service.feed" takes the place of
	the Introspection File and the Search facet in previous versions of		the Introspection File and the Search facet in previous versions of
	the specification. That is, facet discovery, which was previously		the specification. That is, facet discovery, which was previously
	done by inspecting the Introspection file is now done by looking for		done by inspecting the Introspection file is now done by looking for
	"link" tags with an attribute "rel" set to "service.[something]" in		"link" tags with an attribute "rel" set to "service.[something]" in
	the "service.feed" file. At the same time the same representation		the "service.feed" file. At the same time the same representation
	replaces the search facet by having "link" tags that point to other		replaces the search facet by having "link" tags that point to other
	feeds using well knows 'rel' attribute values such as 'next' and		feeds using well knows 'rel' attribute values such as 'next' and
	'prev', or the search can branch in multiple directions by specifying		'prev', or the search can branch in multiple directions by specifying
	multiple link tags with rel="service.feed" and having differing title		multiple link tags with rel="service.feed" and having differing title
	attributes that announce the kind of search results in that feed.		attributes that announce the kind of search results in that feed.
	5.3.1 Locating		3.3.1 Locating
	A link tag of the following format points to the FeedURI.		A link tag of the following format points to the FeedURI.
	<link rel="service.feed"		<link rel="service.feed"
	type="application/x.atom+xml"		type="application/atom+xml"
	The AtomAPI December 2003
	href="URI goes here"		href="URI goes here"
	title="The name of the site.">		title="The name of the site.">
	5.3.2 Request		3.3.2 Request
	The request is a simple GET. No other verbs are currently specified		The request is a simple GET. No other verbs are currently specified
	for this URI.		for this URI.
	5.3.3 Response		3.3.3 Response
	The expected status codes from a GET are 200, 301, 307, and 500. 401,		The expected status codes from a GET are 200, 301, 307, and 500.
	404, and 410 are also possible.		401, 404, and 410 are also possible.
	5.3.3.1 301		3.3.3.1 Response code 301
	The Feed has moved permanently, the new URI is given in the the		The Feed has moved permanently, the new URI is given in the Location
	Location header.		header.
	5.3.3.2 307		3.3.3.2 Response code 307
	The Feed has moved temporarily, the new URI is given in the the		The Feed has moved temporarily, the new URI is given in the Location
	Location header.		header.
	5.4 Link Tag		3.4 Link Tag
	The link tag is used in both HTML and Atom formats. There are slight		The link tag is used in both HTML and Atom formats. There are slight
	differences between the two usages. Here are the commonalities,		differences between the two usages. Here are the commonalities,
	differences, and a list of well-known values for the rel attribute.		differences, and a list of well-known values for the rel attribute.
	The link tag in HTML documents appears in the 'head' of the document.		<http://www.w3.org/TR/html4/struct/links.html#edef-LINK> appears in
	The 'head' section only allows a linear list of 'link' tags. The Atom		the 'head' of the document. The 'head' section only allows a linear
	format allows 'link' tags as children of both the 'feed' element and		list of 'link' tags. The Atom format allows 'link' tags as children
	of the 'entry' element. Note that this gives the information present		of both the 'feed' element and of the 'entry' element. Note that
	in the link tag more context. For example ... @@ TBD @@		this gives the information present in the link tag more context. For
			example ... @@ TBD @@
	5.4.1 rel		3.4.1 rel
	This attribute describes the relationship from the current document,		This attribute describes the relationship from the current document,
	be it HTML or Atom, to the anchor specified by the href attribute.		be it HTML or Atom, to the anchor specified by the href attribute.
	The value of this attribute is a space-separated list of link types.		The value of this attribute is a space-separated list of link types.
	Note that these values are case insensitive. With type="application/		Note that these values are case insensitive. When used in concert
	x.atom+xml" we have the following interpretations of the relations.		with type="application/atom+xml", the relations may be interpreted as
			follows.
	alternate The URI in the href attribute points to an alternate		alternate: The URI in the href attribute points to an alternate
	representation of the containing resource.		representation of the containing resource.
			start: The Atom feed at the URI supplied in the href attribute
	The AtomAPI December 2003
	start The Atom feed at the URI supplied in the href attribute
	contains the first feed in a linear sequence of entries.		contains the first feed in a linear sequence of entries.
			next: The Atom feed at the URI supplied in the href attribute
	next The Atom feed at the URI supplied in the href attribute contains		contains the next N entries in a linear sequence of entries.
	the next N entries in a linear sequence of entries.		prev: The Atom feed at the URI supplied in the href attribute
			contains the previous N entries in a linear sequence of entries.
	prev The Atom feed at the URI supplied in the href attribute contains		service.edit: The URI given in the href attribute is used to edit a
	the previous N entries in a linear sequence of entries.
	service.edit The URI given in the href attribute is used to edit a
	representation of the referred resource.		representation of the referred resource.
			service.post: The URI in the href attribute is used to create new
	service.post The URI in the href attribute is used to create new
	resources.		resources.
			service.feed: The URI given in the href attribute is a starting point
	service.feed The URI given in the href attribute is a starting point
	for navigating content and services.		for navigating content and services.
	5.4.2 href		3.4.2 href
	URI of the resource being described by this link element.		URI of the resource being described by this link element.
	5.4.3 title		3.4.3 title
	Offers advisory information about the link. Rendered to the user to		Offers advisory information about the link. Rendered to the user to
	help them choose among a set of links with the same rel and type		help them choose among a set of links with the same rel and type
	attributes.		attributes.
	5.4.4 type		3.4.4 type
	The content type of the resource avaialable at the URI given in the		The content type of the resource available at the URI given in the
	href attribute of the link element. Most of the link types in this		href attribute of the link element. Most of the link types in this
	specification are on type 'application/x.atom+xml'.		specification are on type 'application/atom+xml'.
	5.5 Atom Request and Response Body Constraints		3.5 Atom Request and Response Body Constraints
	The Atom format is used as the representation of all the resources in		The Atom format is used as the representation of all the resources in
	this specification. As it is used in differing contexts, there are		this specification. As it is used in differing contexts, there are
	different constraints of which elements may be present, and how their		different constraints of which elements may be present, and how their
	values should be interpreted.		values should be interpreted.
	5.5.1 id		3.5.1 id
	PostURI MUST NOT be present.		PostURI MUST NOT be present.
	The AtomAPI December 2003
	FeedURI MUST be present.		FeedURI MUST be present.
	EditURI		EditURI
	GET MUST be present.		GET MUST be present.
	PUT MUST be present.		PUT MUST be present.
	5.5.2 link		3.5.2 link
	PostURI MAY be present. Servers may use the information to determine		PostURI MAY be present. Servers MAY use the information to determine
	the URI of the created resource. Relative URLs are to be		the URI of the created resource. Relative URLs are to be
	interpreted relative to xml:base.		interpreted relative to xml:base.
	FeedURI MUST be present.		FeedURI MUST be present.
	EditURI		EditURI
	GET MUST be present.		GET MUST be present.
	PUT MUST be present.		PUT MUST be present.
	5.5.3 title		3.5.3 title
	PostURI MUST be present. The element may be empty, to explicitly		PostURI MUST be present. The element may be empty, to explicitly
	indicate "no title". Servers SHOULD NOT try to generate a title if		indicate "no title". Servers SHOULD NOT try to generate a title
	one is not provided. The type attribute MAY be present, and if not		if one is not provided. The type attribute MAY be present, and if
	it defaults to "text/plain". If present, it MUST represent a mime		not it defaults to "text/plain". If present, it MUST represent a
	type that the server supports The mode attribute MAY be present,		MIME type that the server supports. The mode attribute MAY be
	if not it defaults to "xml". If present, it must be "xml",		present. If not present, it defaults to "xml". If present, it
	"base64", or "escaped".		MUST be "xml", "base64", or "escaped".
	FeedURI MUST be present.		FeedURI MUST be present.
	EditURI		EditURI
	GET MUST be present.		GET MUST be present.
	PUT MUST be present. The element may be empty, to explicitly		PUT MUST be present. The element may be empty, to explicitly
	indicate "no title". Servers SHOULD NOT try to generate a title		indicate "no title". Servers SHOULD NOT try to generate a
	if one is not provided.		title if one is not provided.
	5.5.4 summary
	The AtomAPI December 2003
	PostURI MAY be present, if not present, indicates the server is		3.5.4 summary</