draft-ietf-atompub-protocol-13.txt   draft-ietf-atompub-protocol-14.txt 
Network Working Group J. Gregorio, Ed. Network Working Group J. Gregorio, Ed.
Internet-Draft IBM Internet-Draft IBM
Intended status: Standards Track B. de hOra, Ed. Intended status: Standards Track B. de hOra, Ed.
Expires: August 9, 2007 Propylon Ltd. Expires: September 5, 2007 Propylon Ltd.
February 5, 2007 March 4, 2007
The Atom Publishing Protocol The Atom Publishing Protocol
draft-ietf-atompub-protocol-13.txt draft-ietf-atompub-protocol-14.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware 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 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. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on August 9, 2007. This Internet-Draft will expire on September 5, 2007.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
Abstract Abstract
The Atom Publishing Protocol (APP) is an application-level protocol The Atom Publishing Protocol (APP) is an application-level protocol
for publishing and editing Web resources. The protocol is based on for publishing and editing Web resources. The protocol is based on
HTTP transport of Atom-formatted representations. The Atom format is HTTP transfer of Atom-formatted representations. The Atom format is
documented in the Atom Syndication Format [RFC4287]. documented in the Atom Syndication Format [RFC4287].
Editorial Note Editorial Note
To provide feedback on this Internet-Draft, join the atom-protocol To provide feedback on this Internet-Draft, join the atom-protocol
mailing list (http://www.imc.org/atom-protocol/index.html) [1]. mailing list (http://www.imc.org/atom-protocol/index.html) [1].
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
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5.4.3. Deleting a Resource . . . . . . . . . . . . . . . . . 13 5.4.3. Deleting a Resource . . . . . . . . . . . . . . . . . 13
5.5. Use of HTTP Response codes . . . . . . . . . . . . . . . . 13 5.5. Use of HTTP Response codes . . . . . . . . . . . . . . . . 13
6. Atom Publishing Protocol Documents . . . . . . . . . . . . . . 14 6. Atom Publishing Protocol Documents . . . . . . . . . . . . . . 14
6.1. Document Types . . . . . . . . . . . . . . . . . . . . . . 14 6.1. Document Types . . . . . . . . . . . . . . . . . . . . . . 14
6.2. Document Extensibility . . . . . . . . . . . . . . . . . . 14 6.2. Document Extensibility . . . . . . . . . . . . . . . . . . 14
7. Category Documents . . . . . . . . . . . . . . . . . . . . . . 16 7. Category Documents . . . . . . . . . . . . . . . . . . . . . . 16
7.1. Example . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.1. Example . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.2. Element Definitions . . . . . . . . . . . . . . . . . . . 16 7.2. Element Definitions . . . . . . . . . . . . . . . . . . . 16
7.2.1. The "app:categories" element . . . . . . . . . . . . . 16 7.2.1. The "app:categories" element . . . . . . . . . . . . . 16
8. Service Documents . . . . . . . . . . . . . . . . . . . . . . 18 8. Service Documents . . . . . . . . . . . . . . . . . . . . . . 18
8.1. Example . . . . . . . . . . . . . . . . . . . . . . . . . 19 8.1. Workspaces . . . . . . . . . . . . . . . . . . . . . . . . 18
8.2. Element Definitions . . . . . . . . . . . . . . . . . . . 20 8.2. Example . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.2.1. The "app:service" Element . . . . . . . . . . . . . . 20 8.3. Element Definitions . . . . . . . . . . . . . . . . . . . 20
8.2.2. The "app:workspace" Element . . . . . . . . . . . . . 20 8.3.1. The "app:service" Element . . . . . . . . . . . . . . 20
8.2.3. The "app:collection" Element . . . . . . . . . . . . . 21 8.3.2. The "app:workspace" Element . . . . . . . . . . . . . 20
8.2.4. The "app:accept" Element . . . . . . . . . . . . . . . 21 8.3.3. The "app:collection" Element . . . . . . . . . . . . . 21
8.2.5. The "app:categories" Element . . . . . . . . . . . . . 22 8.3.4. The "app:accept" Element . . . . . . . . . . . . . . . 21
8.3.5. The "app:categories" Element . . . . . . . . . . . . . 22
9. Creating and Editing Resources . . . . . . . . . . . . . . . . 24 9. Creating and Editing Resources . . . . . . . . . . . . . . . . 24
9.1. Member URIs . . . . . . . . . . . . . . . . . . . . . . . 24 9.1. Member URIs . . . . . . . . . . . . . . . . . . . . . . . 24
9.2. Creating resources with POST . . . . . . . . . . . . . . . 24 9.2. Creating resources with POST . . . . . . . . . . . . . . . 24
9.2.1. Example . . . . . . . . . . . . . . . . . . . . . . . 25 9.2.1. Example . . . . . . . . . . . . . . . . . . . . . . . 25
9.3. Updating Resources with PUT . . . . . . . . . . . . . . . 26 9.3. Updating Resources with PUT . . . . . . . . . . . . . . . 26
9.4. Deleting Resources with DELETE . . . . . . . . . . . . . . 26 9.4. Deleting Resources with DELETE . . . . . . . . . . . . . . 26
9.5. Media Resources and Media Link Entries . . . . . . . . . . 26 9.5. Caching and entity tags . . . . . . . . . . . . . . . . . 26
9.5.1. Examples . . . . . . . . . . . . . . . . . . . . . . . 27 9.5.1. Example . . . . . . . . . . . . . . . . . . . . . . . 26
9.6. The Slug: Header . . . . . . . . . . . . . . . . . . . . . 32 9.6. Media Resources and Media Link Entries . . . . . . . . . . 28
9.6.1. Slug: Header syntax . . . . . . . . . . . . . . . . . 33 9.6.1. Examples . . . . . . . . . . . . . . . . . . . . . . . 29
9.6.2. Example . . . . . . . . . . . . . . . . . . . . . . . 33 9.7. The Slug: Header . . . . . . . . . . . . . . . . . . . . . 35
10. Listing Collections . . . . . . . . . . . . . . . . . . . . . 34 9.7.1. Slug: Header syntax . . . . . . . . . . . . . . . . . 36
10.1. Collection Paging . . . . . . . . . . . . . . . . . . . . 34 9.7.2. Example . . . . . . . . . . . . . . . . . . . . . . . 36
10.2. The "app:edited" Element . . . . . . . . . . . . . . . . . 35 10. Listing Collections . . . . . . . . . . . . . . . . . . . . . 37
11. Atom Format Link Relation Extensions . . . . . . . . . . . . . 36 10.1. Collection partial lists . . . . . . . . . . . . . . . . . 37
11.1. The "edit" Link Relation . . . . . . . . . . . . . . . . . 36 10.2. The "app:edited" Element . . . . . . . . . . . . . . . . . 38
11.2. The "edit-media" Link Relation . . . . . . . . . . . . . . 36 11. Atom Format Link Relation Extensions . . . . . . . . . . . . . 40
12. The Atom Format Type Parameter . . . . . . . . . . . . . . . . 37 11.1. The "edit" Link Relation . . . . . . . . . . . . . . . . . 40
12.1. The 'type' parameter . . . . . . . . . . . . . . . . . . . 37 11.2. The "edit-media" Link Relation . . . . . . . . . . . . . . 40
12.1.1. Conformance . . . . . . . . . . . . . . . . . . . . . 37 12. The Atom Format Type Parameter . . . . . . . . . . . . . . . . 41
13. Atom Publishing Controls . . . . . . . . . . . . . . . . . . . 38 12.1. The 'type' parameter . . . . . . . . . . . . . . . . . . . 41
13.1. The "app:control" Element . . . . . . . . . . . . . . . . 38 12.1.1. Conformance . . . . . . . . . . . . . . . . . . . . . 41
13.1.1. The "app:draft" Element . . . . . . . . . . . . . . . 38 13. Atom Publishing Controls . . . . . . . . . . . . . . . . . . . 42
14. Securing the Atom Publishing Protocol . . . . . . . . . . . . 39 13.1. The "app:control" Element . . . . . . . . . . . . . . . . 42
15. Security Considerations . . . . . . . . . . . . . . . . . . . 40 13.1.1. The "app:draft" Element . . . . . . . . . . . . . . . 42
15.1. Denial of Service . . . . . . . . . . . . . . . . . . . . 40 14. Securing the Atom Publishing Protocol . . . . . . . . . . . . 43
15.2. Replay Attacks . . . . . . . . . . . . . . . . . . . . . . 40 15. Security Considerations . . . . . . . . . . . . . . . . . . . 44
15.3. Spoofing Attacks . . . . . . . . . . . . . . . . . . . . . 40 15.1. Denial of Service . . . . . . . . . . . . . . . . . . . . 44
15.4. Linked Resources . . . . . . . . . . . . . . . . . . . . . 40 15.2. Replay Attacks . . . . . . . . . . . . . . . . . . . . . . 44
15.5. Digital Signatures and Encryption . . . . . . . . . . . . 40 15.3. Spoofing Attacks . . . . . . . . . . . . . . . . . . . . . 44
15.6. URIs and IRIs . . . . . . . . . . . . . . . . . . . . . . 40 15.4. Linked Resources . . . . . . . . . . . . . . . . . . . . . 44
16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 41 15.5. Digital Signatures and Encryption . . . . . . . . . . . . 44
15.6. URIs and IRIs . . . . . . . . . . . . . . . . . . . . . . 44
16. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 45
16.1. Content-type registration for 16.1. Content-type registration for
'application/atomserv+xml' . . . . . . . . . . . . . . . . 41 'application/atomserv+xml' . . . . . . . . . . . . . . . . 45
16.2. Content-type registration for 'application/atomcat+xml' . 42 16.2. Content-type registration for 'application/atomcat+xml' . 46
16.3. Header field registration for 'SLUG' . . . . . . . . . . . 43 16.3. Header field registration for 'SLUG' . . . . . . . . . . . 47
16.4. The Link Relation registration "edit" . . . . . . . . . . 44 16.4. The Link Relation registration "edit" . . . . . . . . . . 48
16.5. The Link Relation registration "edit-media" . . . . . . . 44 16.5. The Link Relation registration "edit-media" . . . . . . . 48
16.6. The Atom Format Media Type Parameter . . . . . . . . . . . 44 16.6. The Atom Format Media Type Parameter . . . . . . . . . . . 48
17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 45 17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 49
17.1. Normative References . . . . . . . . . . . . . . . . . . . 45 17.1. Normative References . . . . . . . . . . . . . . . . . . . 49
17.2. Informative References . . . . . . . . . . . . . . . . . . 46 17.2. Informative References . . . . . . . . . . . . . . . . . . 50
Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 48 Appendix A. Contributors . . . . . . . . . . . . . . . . . . . . 52
Appendix B. RELAX NG Compact Schema . . . . . . . . . . . . . . . 49 Appendix B. RELAX NG Compact Schema . . . . . . . . . . . . . . . 53
Appendix C. Revision History . . . . . . . . . . . . . . . . . . 55 Appendix C. Revision History . . . . . . . . . . . . . . . . . . 59
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 58 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 63
Intellectual Property and Copyright Statements . . . . . . . . . . 59 Intellectual Property and Copyright Statements . . . . . . . . . . 64
1. Introduction 1. Introduction
The Atom Publishing Protocol is an application-level protocol for The Atom Publishing Protocol is an application-level protocol for
publishing and editing Web resources using HTTP [RFC2616] and XML 1.0 publishing and editing Web resources using HTTP [RFC2616] and XML 1.0
[W3C.REC-xml]. The protocol supports the creation of Web resources [W3C.REC-xml]. The protocol supports the creation of Web resources
and provides facilities for: and provides facilities for:
o Collections: Sets of resources, which can be retrieved in whole or o Collections: Sets of resources, which can be retrieved in whole or
in part. in part.
o Service: Discovering and describing Collections. o Services: Discovery and description of Collections.
o Editing: Creating, updating and deleting resources. o Editing: Creating, updating and deleting resources.
The Atom Publishing Protocol is different from many contemporary The Atom Publishing Protocol is different from many contemporary
protocols in that the server is given wide latitude in processing protocols in that the server is given wide latitude in processing
requests from clients. See Section 4 for more details. requests from clients. See Section 4 for more details.
2. Notational Conventions 2. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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2.1.3. Use of xml:base and xml:lang 2.1.3. Use of xml:base and xml:lang
XML elements defined by this specification MAY have an xml:base XML elements defined by this specification MAY have an xml:base
attribute [W3C.REC-xmlbase-20010627]. When xml:base is used, it attribute [W3C.REC-xmlbase-20010627]. When xml:base is used, it
serves the function described in Section 5.1.1 of URI Generic Syntax serves the function described in Section 5.1.1 of URI Generic Syntax
[RFC3986], by establishing the base URI (or IRI) for resolving [RFC3986], by establishing the base URI (or IRI) for resolving
relative references found within the scope of the xml:base attribute. relative references found within the scope of the xml:base attribute.
Any element defined by this specification MAY have an xml:lang Any element defined by this specification MAY have an xml:lang
attribute, whose content indicates the natural language for the attribute, whose content indicates the natural language for the
element and its descendents. The language context is only element and its descendents. Requirements regarding the content and
significant for elements and attributes declared to be "Language- interpretation of xml:lang are specified in Section 2.12 of XML 1.0
Sensitive" by this specification. Requirements regarding the content [W3C.REC-xml].
and interpretation of xml:lang are specified in Section 2.12 of XML
1.0 [W3C.REC-xml].
3. Terminology 3. Terminology
For convenience, this protocol can be referred to as the "Atom For convenience, this protocol can be referred to as the "Atom
Protocol" or "APP". Protocol" or "APP".
URI/IRI - A Uniform Resource Identifier and Internationalized URI/IRI - A Uniform Resource Identifier and Internationalized
Resource Identifier. These terms and the distinction between them Resource Identifier. These terms and the distinction between them
are defined in [RFC3986] and [RFC3987]. Before an IRI found in a are defined in [RFC3986] and [RFC3987]. Before an IRI found in a
document is used by HTTP, the IRI is first converted to a URI (see document is used by HTTP, the IRI is first converted to a URI (see
Section 4). Section 4).
The phrase "the URI of a document" in this specification is shorthand In this specification the phrase "the URI of a document" is shorthand
for "a URI which, when dereferenced, is expected to produce that for "a URI which, when dereferenced, is expected to produce that
document as a representation". document as a representation".
Resource - A network-accessible data object or service identified by Resource - A network-accessible data object or service identified by
an IRI, as defined in [RFC2616]. See [W3C.REC-webarch-20041215] for an IRI, as defined in [RFC2616]. See [W3C.REC-webarch-20041215] for
further discussion on resources. further discussion on resources.
Representation - An entity included with a request or response as Representation - An entity included with a request or response as
defined in [RFC2616]. defined in [RFC2616].
Collection - A resource that contains a set of Member Entries. See Collection - A resource that contains a set of Member Entries. See
Section 9. Section 9.
Member - A resource whose IRI is listed in a Collection by a link Member - A resource whose IRI is listed in a Collection by a link
element with a relation of "edit" or "edit-media". See Section 9.1. element with a relation of "edit" or "edit-media". See Section 9.1.
The protocol defines two kinds of Members - Entry and Media
resources.
Workspace - A named group of Collections. See Section 8. Entry Resource - Member Resources of a Collection that are
represented using the "application/atom+xml" media type.
Media Resource -Member Resources of a Collection that are represented
with a media type other than "application/atom+xml".
Media Link Entry - an Entry Resource that contains metadata about a
Media Resource.
Workspace - A named group of Collections. See Section 8.1.
Service Document - A document that describes the location and Service Document - A document that describes the location and
capabilities of one or more Collections. See Section 8. capabilities of one or more Collections. See Section 8.
Category Document - A document that describes the categories allowed Category Document - A document that describes the categories allowed
in a Collection. See Section 7. in a Collection. See Section 7.
4. Protocol Model 4. Protocol Model
The Atom Publishing Protocol uses HTTP methods to author Member The Atom Publishing Protocol uses HTTP methods to author Member
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o POST is used to create a new, dynamically-named, resource. When o POST is used to create a new, dynamically-named, resource. When
the client submits non-Atom-Entry representations to a Collection the client submits non-Atom-Entry representations to a Collection
for creation, two resources are always created - a Media Entry for for creation, two resources are always created - a Media Entry for
the requested resource, and a Media Link Entry for metadata (in the requested resource, and a Media Link Entry for metadata (in
Atom Entry format) about the resource. Atom Entry format) about the resource.
o PUT is used to update a known resource. o PUT is used to update a known resource.
o DELETE is used to remove a known resource. o DELETE is used to remove a known resource.
This document does not specify the form of the URIs that are used. The Atom Protocol does not specify the form of the URIs that are
HTTP ([RFC2616]) specifies that the URI space of each server is used. HTTP ([RFC2616]) specifies that the URI space of each server
controlled by that server and the Atom Protocol imposes no is controlled by that server, and this protocol imposes no further
constraints on that control. What this RFC does specify are the constraints on that control. What is specified here are the formats
formats of the representations that are exchanged and the actions of the representations that are exchanged and the actions that can be
that can be performed on the IRIs embedded in those documents. performed on the IRIs embedded in those representations.
This document only covers the creation, update and deletion of Entry The Atom Protocol only covers the creation, update and deletion of
and Media resources. Other resources can be created, updated, and Entry and Media resources. Other resources could be created,
deleted as the result of manipulating a Collection, but the number of updated, and deleted as the result of manipulating a Collection, but
those resources, their media-types, and effects of Atom Protocol the number of those resources, their media-types, and effects of Atom
operations on them are outside the scope of this specification. Protocol operations on them are outside the scope of this
specification.
Since all aspects of client-server interaction are defined in terms Since all aspects of client-server interaction are defined in terms
of HTTP, [RFC2616] should be consulted for any areas not covered in of HTTP, [RFC2616] should be consulted for any areas not covered in
this specification. this specification.
Along with operations on Member Resources, the Atom Protocol defines Along with operations on Member Resources, the Atom Protocol defines
Collection Resources for managing and organizing Member Resources. Collection Resources for managing and organizing Member Resources.
Collections are represented by Atom Feed documents and contain the The representation of Collections are Atom Feed documents, and
IRIs of, and metadata about, their Member Resources. The Atom contain the IRIs of, and metadata about the Collection's Member
Protocol does not make a structural distinction between Feeds used Resources. The Atom Protocol does not make a structural distinction
for Collections and other Atom Feeds. The only mechanism that this between Feeds used for Collections and other Atom Feeds. The only
specification supplies for distinguishing a Collection Feed is its mechanism that this specification supplies for indicating a
appearance in a Service Document. Collection Feed is its appearance in a Service Document.
Atom Protocol documents allow the use of IRIs [RFC3987], as well as Atom Protocol documents allow the use of IRIs [RFC3987], as well as
URIs [RFC3986]. Before an IRI found in a document is used by HTTP, URIs [RFC3986]. Before an IRI found in a document is used by HTTP,
the IRI is first converted to a URI according the procedure defined the IRI is first converted to a URI according the procedure defined
in Section 3.1 of [RFC3987]. In accordance with that specification, in Section 3.1 of [RFC3987]. In accordance with that specification,
this conversion SHOULD be applied as late as possible. The IRI, and this conversion SHOULD be applied as late as possible. Conversion
the URI into which it is converted, identify the same resource. does not imply resource creation - the IRI and the URI into which it
is converted identify the same resource.
There are two kinds of Member Resources - Member Entry Resources and There are two kinds of Member Resources - Entry Resources and Media
Media Resources. Member Entry Resources are represented as Atom Resources. Entry Resources are represented as Atom Entries
Entries [RFC4287]. Media Resources can have representations in any [RFC4287]. Media Resources can have representations in any media
media type. A Media Link Entry is a Member Entry that contains type. A Media Link Entry is an Entry Resource that contains metadata
metadata about a Media Resource. This diagram shows the about a Media Resource. This diagram shows the classification of the
classification of the resources: resources:
Member Resource Member Resource
-> Member Entry Resource -> Entry Resource
-> Media Link Entry Resource -> Media Link Entry
-> Media Resource -> Media Resource
A Collection's Atom Entries contain the Member Entry and Media A Collection Feed's Atom Entries contain the Entry and Media Resource
Resources IRIs of the Collection. A Collection can contain any IRIs of the Collection. A Collection Feed can contain any number of
number of Entries for either kind. In the diagram of a Collection Entries for either kind, or an ordered subset of the Entries (see
below, there are two Entries. The first contains the IRI of a Member Section 10.1). In the diagram of a Collection below, there are two
Entry Resource. The second contains the IRIs of both a Media Entries. The first contains the IRI of an Entry Resource. The
Resource and a Media Link Entry Resource, which contains the metadata second contains the IRIs of both a Media Resource and a Media Link
for that Media Resource: Entry Resource, which contains the metadata for that Media Resource:
Collection Collection
Entry Entry
Member Entry IRI -> Member Entry Resource Member Entry IRI -> Entry Resource
Entry Entry
Member Entry IRI -> Media Link Entry Resource Member Entry IRI -> Media Link Entry
Media IRI -> Media Resource Media IRI -> Media Resource
Service Documents represent server-defined groups of Collections, and Service Documents represent server-defined groups of Collections, and
are used to initialize the process of creating and editing resources. are used to initialize the process of creating and editing resources.
4.1. Client Implementation Considerations 4.1. Client Implementation Considerations
The Atom Protocol imposes few restrictions on the actions of servers. The Atom Protocol imposes few restrictions on the actions of servers.
Unless a constraint is specified here, servers can be expected to Unless a constraint is specified here, servers can be expected to
vary in behavior, in particular around the manipulation of Atom vary in behavior, in particular around the manipulation of Atom
Entries sent by clients. For example, although this specification Entries sent by clients. For example, although this specification
only defines the expected behavior of Collections with respect to GET only defines the expected behavior of Collections with respect to GET
and POST, this does not imply that PUT, DELETE, PROPPATCH and others and POST, this does not imply that PUT, DELETE, PROPPATCH and others
are forbidden on Collection resources - only that this specification are forbidden on Collection resources - only that this specification
does not define what the servers response would be to those methods. does not define what the server's response would be to those methods.
Similarly while some HTTP status codes are mentioned explicitly, Similarly while some HTTP status codes are mentioned explicitly,
clients should be prepared to handle any status code from a server. clients ought to be prepared to handle any status code from a server.
Servers can choose to accept, reject, delay, moderate, censor, Servers can choose to accept, reject, delay, moderate, censor,
reformat, translate, relocate or recategorize the content submitted reformat, translate, relocate or recategorize the content submitted
to them. Only some of these choices are immediately relayed back to to them. Only some of these choices are immediately relayed back to
the client in responses to client requests; other choices may only the client in responses to client requests; other choices may only
become apparent later, in the feed or published entries. The same become apparent later, in the feed or published entries. The same
series of requests to two different publishing sites can result in a series of requests to two different publishing sites can result in a
different series of HTTP responses, different resulting feeds or different series of HTTP responses, different resulting feeds or
different entry contents. different entry contents.
As a result, client software has to be written flexibly to accept As a result, client software has to be written flexibly to accept
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group of Collections and the capabilities of those Collections group of Collections and the capabilities of those Collections
supported by the server. The content of this document can vary supported by the server. The content of this document can vary
based on aspects of the client request, including, but not based on aspects of the client request, including, but not
limited to, authentication credentials. limited to, authentication credentials.
5.2. Listing Collection Members 5.2. Listing Collection Members
To list the members of a Collection, the client sends a GET request To list the members of a Collection, the client sends a GET request
to the URI of a Collection. An Atom Feed Document is returned whose to the URI of a Collection. An Atom Feed Document is returned whose
Entries contain the IRIs of Member Resources. The returned Feed may Entries contain the IRIs of Member Resources. The returned Feed may
describe all, or only a subset, of the Members in a Collection (see describe all, or only a partial list of the Members in a Collection
Section 10). Section 11 describes extensions to the Atom Syndication (see Section 10).
Format used in the Atom Protocol.
Client Server Client Server
| | | |
| 1.) GET to Collection URI | | 1.) GET to Collection URI |
|------------------------------->| |------------------------------->|
| | | |
| 2.) Atom Feed Doc | | 2.) Atom Feed Doc |
|<-------------------------------| |<-------------------------------|
| | | |
skipping to change at page 12, line 22 skipping to change at page 12, line 22
| 2.) 201 Created | | 2.) 201 Created |
| Location: Member Entry URI | | Location: Member Entry URI |
|<------------------------------------------| |<------------------------------------------|
| | | |
1. The client POSTs a representation of the Member to the URI of the 1. The client POSTs a representation of the Member to the URI of the
Collection. Collection.
2. If the Member Resource was created successfully, the server 2. If the Member Resource was created successfully, the server
responds with a status code of 201 and a Location: header that responds with a status code of 201 and a Location: header that
contains the IRI of the newly created Member Entry Resource. contains the IRI of the newly created Entry Resource. Media
Media Resources could have also been created and their IRIs can Resources could have also been created and their IRIs can be
be found through the Member Entry Resource. See Section 9.5 for found through the Entry Resource. See Section 9.6 for more
more details. details.
5.4. Editing a Resource 5.4. Editing a Resource
Once a resource has been created and its Member URI is known, that Once a resource has been created and its Member URI is known, that
URI can be used to retrieve, update, and delete the resource. URI can be used to retrieve, update, and delete the resource.
Section 11 describes extensions to the Atom Syndication Format used
in the Atom Protocol for editing purposes.
5.4.1. Retrieving a Resource 5.4.1. Retrieving a Resource
Client Server Client Server
| | | |
| 1.) GET to Member URI | | 1.) GET to Member URI |
|------------------------------------------>| |------------------------------------------>|
| | | |
| 2.) Member Representation | | 2.) Member Representation |
|<------------------------------------------| |<------------------------------------------|
skipping to change at page 13, line 28 skipping to change at page 13, line 28
2. If the update is successful the server responds with a status 2. If the update is successful the server responds with a status
code of 200. code of 200.
5.4.3. Deleting a Resource 5.4.3. Deleting a Resource
Client Server Client Server
| | | |
| 1.) DELETE to Member URI | | 1.) DELETE to Member URI |
|------------------------------------------>| |------------------------------------------>|
| | | |
| 2.) 200 Ok | | 2.) 200 OK |
|<------------------------------------------| |<------------------------------------------|
| | | |
1. The client sends a DELETE request to the URI of a Member 1. The client sends a DELETE request to the URI of a Member
Resource. Resource.
2. If the deletion is successful the server responds with a status 2. If the deletion is successful the server responds with a status
code of 200. code of 200.
A different approach is taken for deleting Media Resources, see A different approach is taken for deleting Media Resources; see
Section 9.5 for details. Section 9.6 for details.
5.5. Use of HTTP Response codes 5.5. Use of HTTP Response codes
The Atom Protocol uses the response status codes defined in HTTP to The Atom Protocol uses the response status codes defined in HTTP to
indicate the success or failure of an operation. Consult the HTTP indicate the success or failure of an operation. Consult the HTTP
specification [RFC2616] for detailed definitions of each status code. specification [RFC2616] for detailed definitions of each status code.
Implementers are asked to note that according to the HTTP Implementers are asked to note that according to the HTTP
specification, HTTP 4xx and 5xx response entities SHOULD include a specification, HTTP 4xx and 5xx response entities SHOULD include a
human-readable explanation of the error. human-readable explanation of the error.
6. Atom Publishing Protocol Documents 6. Atom Publishing Protocol Documents
6.1. Document Types 6.1. Document Types
This specification describes two kinds of Documents - Category This specification defines two kinds of Documents - Category
Documents and Service Documents. Documents and Service Documents.
A Category Document (Section 7) contains lists of categories A Category Document (Section 7) contains lists of categories
specified using the "atom:category" element from the Atom Syndication specified using the "atom:category" element from the Atom Syndication
Format. A Service Document (Section 8) describes Workspaces, which Format.
are server-defined groups of Collections. This specification assigns
no meaning to Workspaces; that is, a Workspace does not imply any A Service Document (Section 8) groups available Collections into
specific processing assumptions. Operations on Workspaces Workspaces.
themselves, such as creation or deletion, are not defined by this
specification.
The namespace name [W3C.REC-xml-names] for either kind of document The namespace name [W3C.REC-xml-names] for either kind of document
is: is:
http://purl.org/atom/app# http://purl.org/atom/app#
[[anchor8: The namespace name needs to be updated with the final URI [[anchor8: The namespace name needs to be updated with the final URI
upon publication]] upon publication]]
This specification uses the prefix "app:" for the namespace name. This specification uses the prefix "app:" for the namespace name.
The prefix "atom:" is used for "http://www.w3.org/2005/Atom", the The prefix "atom:" is used for "http://www.w3.org/2005/Atom", the
namespace name of the Atom Syndication Format [RFC4287]. The namespace name of the Atom Syndication Format [RFC4287]. These
namespace prefixes are not semantically significant. namespace prefixes are not semantically significant.
Atom Publishing Protocol Documents MUST be well-formed XML. This Atom Publishing Protocol Documents MUST be well-formed XML. This
specification does not define any DTDs for Atom Protocol formats, and specification does not define any DTDs for Atom Protocol formats, and
hence does not require them to be "valid" in the sense used by XML. hence does not require them to be "valid" in the sense used by XML.
6.2. Document Extensibility 6.2. Document Extensibility
Unrecognized markup in an Atom Publishing Protocol document is Unrecognized markup in an Atom Publishing Protocol document is
considered "foreign markup" as defined in [RFC4287]. Such foreign considered "foreign markup" as defined in Section 6 of [RFC4287].
markup can be used anywhere within a Category or Service Document Such foreign markup can be used anywhere within a Category or Service
unless it is explicitly forbidden. Processors that encounter foreign Document unless it is explicitly forbidden. Processors that
markup MUST NOT stop processing and MUST NOT signal an error. encounter foreign markup MUST NOT stop processing and MUST NOT signal
Clients SHOULD preserve foreign markup when transmitting such an error. Clients SHOULD preserve foreign markup when transmitting
documents. such documents.
The namespace name "http://purl.org/atom/app#" is reserved for The namespace name "http://purl.org/atom/app#" is reserved for
forward compatible revisions of the Category and Service Document forward compatible revisions of the Category and Service Document
types - this does not exclude the addition of elements and attributes types - this does not exclude the addition of elements and attributes
that might not be recognized by processors conformant to this that might not be recognized by processors conformant to this
specification. Such unrecognized markup from the specification. Such unrecognized markup from the
"http://purl.org/atom/app#" namespace MUST be treated as foreign "http://purl.org/atom/app#" namespace MUST be treated as foreign
markup. markup.
[[anchor9: The namespace name needs to be updated with the final URI [[anchor9: The namespace name needs to be updated with the final URI
upon publication]] upon publication]]
7. Category Documents 7. Category Documents
Category Documents contain lists of categories described using the Category Documents contain lists of categories described using the
"atom:category" element from the Atom Syndication Format [RFC4287]. "atom:category" element from the Atom Syndication Format [RFC4287].
Categories can also appear in Service Documents, where they describe Categories can also appear in Service Documents, where they describe
the categories allowed in a Collection (see Section 8.2.5). the categories allowed in a Collection (see Section 8.3.5).
Category Documents are identified with the "application/atomcat+xml" Category Documents are identified with the "application/atomcat+xml"
media type (see Section 16). media type (see Section 16).
7.1. Example 7.1. Example
<?xml version="1.0" ?> <?xml version="1.0" ?>
<app:categories <app:categories
xmlns:app="http://purl.org/atom/app#" xmlns:app="http://purl.org/atom/app#"
xmlns="http://www.w3.org/2005/Atom" xmlns="http://www.w3.org/2005/Atom"
skipping to change at page 16, line 49 skipping to change at page 17, line 5
The root of a Category Document is the "app:categories" element. An The root of a Category Document is the "app:categories" element. An
app:categories element can contain zero or more "atom:category" app:categories element can contain zero or more "atom:category"
elements from the Atom namespace ("http://www.w3.org/2005/Atom"). elements from the Atom namespace ("http://www.w3.org/2005/Atom").
An app:category child element that has no "scheme" attribute inherits An app:category child element that has no "scheme" attribute inherits
the attribute from its app:categories parent. An app:category child the attribute from its app:categories parent. An app:category child
element with an existing "scheme" attribute does not inherit the element with an existing "scheme" attribute does not inherit the
"scheme" value of its "app:categories" parent element. "scheme" value of its "app:categories" parent element.
7.2.1.1. Attributes of "app:categories"
The app:categories element can contain a "fixed" attribute, with a
value of either "yes" or "no", indicating whether the list of
categories is a fixed or an open set. Attempts to create or update
members whose categories are not listed in the Collection Document
MAY be rejected by the server. Collections that indicate the
category set is open SHOULD NOT reject otherwise acceptable members
whose categories are not listed by the Collection.
Alternatively, the app:categories element MAY contain an "href"
attribute, whose value MUST be an IRI reference identifying a
Category Document. If the "href" attribute is provided, the app:
categories element MUST be empty and MUST NOT have the "fixed" or
"scheme" attributes.
atomCategory = atomCategory =
element atom:category { element atom:category {
atomCommonAttributes, atomCommonAttributes,
attribute term { text }, attribute term { text },
attribute scheme { atomURI }?, attribute scheme { atomURI }?,
attribute label { text }?, attribute label { text }?,
undefinedContent undefinedContent
} }
appInlineCategories = appInlineCategories =
skipping to change at page 18, line 5 skipping to change at page 17, line 29
} }
appOutOfLineCategories = appOutOfLineCategories =
element app:categories { element app:categories {
attribute href { atomURI }, attribute href { atomURI },
undefinedContent undefinedContent
} }
appCategories = appInlineCategories | appOutOfLineCategories appCategories = appInlineCategories | appOutOfLineCategories
7.2.1.1. Attributes of "app:categories"
The app:categories element can contain a "fixed" attribute, with a
value of either "yes" or "no", indicating whether the list of
categories is a fixed or an open set. The absence of the "fixed"
attribute is equivalent to the presence of a "fixed" attribute with a
value of "no".
Alternatively, the app:categories element MAY contain an "href"
attribute, whose value MUST be an IRI reference identifying a
Category Document. If the "href" attribute is provided, the app:
categories element MUST be empty and MUST NOT have the "fixed" or
"scheme" attributes.
8. Service Documents 8. Service Documents
For authoring to commence, a client needs to discover the For authoring to commence, a client needs to discover the
capabilities and locations of the available Collections. Service capabilities and locations of the available Collections. Service
Documents are designed to support this discovery process. How Documents are designed to support this discovery process.
Service Documents are discovered is not defined in this
How Service Documents are discovered is not defined in this
specification. specification.
A Service Document describes Workspaces, which are server-defined Service Documents are identified with the "application/atomserv+xml"
groups of Collections. Service Documents are identified with the media type (see Section 16).
"application/atomserv+xml" media type (see Section 16).
8.1. Workspaces
A Service Document groups a server's Collections into Workspaces.
Operations on Workspaces, such as creation or deletion, are not
defined by this specification. In general, this specification
assigns no meaning to Workspaces; that is, a Workspace does not imply
any specific processing assumptions.
There is no requirement that a server support multiple Workspaces. There is no requirement that a server support multiple Workspaces.
In addition, a Collection MAY appear in more than one Workspace. In addition, a Collection MAY appear in more than one Workspace.
8.1. Example 8.2. Example
<?xml version="1.0" encoding='utf-8'?> <?xml version="1.0" encoding='utf-8'?>
<service xmlns="http://purl.org/atom/app#" <service xmlns="http://purl.org/atom/app#"
xmlns:atom="http://www.w3.org/2005/Atom"> xmlns:atom="http://www.w3.org/2005/Atom">
<workspace> <workspace>
<atom:title>Main Site</atom:title> <atom:title>Main Site</atom:title>
<collection <collection
href="http://example.org/reilly/main" > href="http://example.org/reilly/main" >
<atom:title>My Blog Entries</atom:title> <atom:title>My Blog Entries</atom:title>
<categories <categories
skipping to change at page 19, line 42 skipping to change at page 19, line 42
scheme="http://example.org/extra-cats/" scheme="http://example.org/extra-cats/"
term="joke" /> term="joke" />
<atom:category <atom:category
scheme="http://example.org/extra-cats/" scheme="http://example.org/extra-cats/"
term="serious" /> term="serious" />
</categories> </categories>
</collection> </collection>
</workspace> </workspace>
</service> </service>
This Service Document describes two Workspaces. The first Workspace The Service Document above describes two Workspaces. The first
is called "Main Site", has two Collections called "My Blog Entries" Workspace is called "Main Site", and has two Collections called "My
and "Pictures" whose IRIs are "http://example.org/reilly/main" and Blog Entries" and "Pictures", whose IRIs are
"http://example.org/reilly/pic" respectively. The "Pictures" "http://example.org/reilly/main" and "http://example.org/reilly/pic"
Workspace includes an "accept" element indicating that a client can respectively. The "Pictures" Workspace includes an "accept" element
post image files to the Collection to create new Media Resources. indicating that a client can post image files to the Collection to
Entries with associated Media Resources are discussed in Section 9.5. create new Media Resources (entries with associated Media Resources
are discussed in Section 9.6).
The second Workspace is called "Side Bar Blog" and has a single The second Workspace is called "Side Bar Blog" and has a single
Collection called "Remaindered Links" whose IRI is Collection called "Remaindered Links" whose IRI is
"http://example.org/reilly/list". "http://example.org/reilly/list".
Within each of the two Entry collections, the categories element Within each of the two Entry collections, the categories element
provides a list of available categories for Member Entries. In the provides a list of available categories for Member Entries. In the
"My Blog Entries" Collection, the list of available categories is "My Blog Entries" Collection, the list of available categories is
obtainable through the "href" attribute. The "Side Bar Blog" available through the "href" attribute. The "Side Bar Blog"
Collection provides a category list within the Service Document, but Collection provides a category list within the Service Document, but
states the list is fixed, signaling a request from the server that states the list is fixed, signaling a request from the server that
Entries be POSTed using only those two categories. Entries be POSTed using only those two categories.
8.2. Element Definitions 8.3. Element Definitions
8.2.1. The "app:service" Element 8.3.1. The "app:service" Element
The root of a Service Document is the "app:service" element. The root of a Service Document is the "app:service" element.
The "app:service" element is the container for service information The "app:service" element is the container for service information
associated with one or more Workspaces. An app:service element MUST associated with one or more Workspaces. An app:service element MUST
contain one or more app:workspace elements. contain one or more app:workspace elements.
namespace app = "http://purl.org/atom/app#" namespace app = "http://purl.org/atom/app#"
start = appService start = appService
appService = appService =
element app:service { element app:service {
appCommonAttributes, appCommonAttributes,
( appWorkspace+ ( appWorkspace+
& extensionElement* ) & extensionElement* )
} }
8.2.2. The "app:workspace" Element 8.3.2. The "app:workspace" Element
The "app:workspace" element contains information elements about the Workspaces are server-defined groups of Collections. The "app:
Collections of resources available for editing. The app:workspace workspace" element contains zero or more app:collection elements
element contains zero or more app:collection elements. describing the Collections of resources available for editing.
appWorkspace = appWorkspace =
element app:workspace { element app:workspace {
appCommonAttributes, appCommonAttributes,
( atomTitle ( atomTitle
& appCollection* & appCollection*
& extensionSansTitleElement* ) & extensionSansTitleElement* )
} }
atomTitle = element atom:title { atomTextConstruct } atomTitle = element atom:title { atomTextConstruct }
8.2.2.1. The "atom:title" Element 8.3.2.1. The "atom:title" Element
The app:workspace element MUST contain one "atom:title" element (as The app:workspace element MUST contain one "atom:title" element (as
defined in [RFC4287]), giving a human-readable title for the defined in [RFC4287]), giving a human-readable title for the
Workspace. Workspace.
8.2.3. The "app:collection" Element 8.3.3. The "app:collection" Element
The "app:collection" element describes a Collection. The app: The "app:collection" element describes a Collection. The app:
collection element MAY contain one app:accept element and MAY contain collection element MAY contain one app:accept element and MAY contain
any number of app:categories elements. The app:collection element any number of app:categories elements. The app:collection element
MUST NOT contain more than one app:accept element. MUST NOT contain more than one app:accept element.
appCollection = appCollection =
element app:collection { element app:collection {
appCommonAttributes, appCommonAttributes,
attribute href { atomURI }, attribute href { atomURI },
( atomTitle ( atomTitle
& appAccept? & appAccept?
& appCategories* & appCategories*
& extensionSansTitleElement* ) & extensionSansTitleElement* )
} }
8.2.3.1. Usage in Atom Feed Documents 8.3.3.1. Usage in Atom Feed Documents
The app:collection element MAY appear as a child of an atom:feed or The app:collection element MAY appear as a child of an atom:feed or
atom:source element in an Atom Feed Document. Its value identifies a atom:source element in an Atom Feed Document. Its content identifies
Collection by which new Entries can be added to appear in the feed. a Collection by which new Entries can be added to appear in the feed.
The app:collection element is considered foreign markup as defined in The app:collection element is considered foreign markup as defined in
Section 6 of [RFC4287]. Section 6 of [RFC4287].
8.2.3.2. The "href" Attribute 8.3.3.2. The "href" Attribute
The app:collection element MUST contain an "href" attribute, whose The app:collection element MUST contain an "href" attribute, whose
value gives the IRI of the Collection. value gives the IRI of the Collection.
8.2.3.3. The "atom:title" Element 8.3.3.3. The "atom:title" Element
The app:collection Element MUST contain one "atom:title" element (as The app:collection Element MUST contain one "atom:title" element (as
defined in [RFC4287]), giving a human-readable title for the defined in [RFC4287]), giving a human-readable title for the
Collection. Collection.
8.2.4. The "app:accept" Element 8.3.4. The "app:accept" Element
The "app:accept" element value specifies a comma-separated list of The "app:accept" element value specifies a comma-separated list of
media-ranges (see [RFC2616]) identifying the types of representations media-ranges (see [RFC2616]). The list identifies the types of
that can be POSTed to the URI of a Collection. Whitespace around and representations that can be POSTed to the URI of a Collection.
between media-range values is considered insignificant and MUST be
ignored. Whitespace around and between media-range values is insignificant and
MUST be ignored.
The app:accept element is similar to the HTTP Accept request-header The app:accept element is similar to the HTTP Accept request-header
[RFC2616] with the exception that app:accept has no notion of [RFC2616] with the exception that app:accept has no notion of
preference. As a result, the value syntax of app:accept does not use preference. As a result, the value syntax of app:accept does not use
"accept-params" or "q" arguments as specified in [RFC2616], section "accept-params" or "q" arguments as specified in [RFC2616], section
14.1. 14.1.
The order of media-ranges is not significant. The following lists The order of media-ranges is not significant. For example, the
are all equivalent: following lists are all equivalent:
<app:accept>image/png,image/*</app:accept> <app:accept>image/png,image/*</app:accept>
<app:accept>image/*, image/png</app:accept> <app:accept>image/*, image/png</app:accept>
<app:accept> image/* </app:accept> <app:accept> image/* </app:accept>
A value of "entry" may appear in any list of media-ranges in an A value of "entry" MAY appear in any list of media-ranges and
accept element and indicates that Atom Entry Documents can be POSTed indicates that Atom Entry Documents can be POSTed to the Collection.
to the Collection. If the accept element exists but is empty, The value is equivalent to the media type and format parameter
clients SHOULD assume that the Collection does not support the "application/atom+xml;type=entry", as defined in Section 12. If the
creation of new Entries. If the accept element is not present, accept element exists but is empty, clients SHOULD assume that the
clients SHOULD treat this as equivalent to <app:accept>entry</ Collection does not support the creation of new Entries. If the
app:accept>. accept element is not present, clients SHOULD treat this as
equivalent to <app:accept>entry</app:accept>.
appAccept = appAccept =
element app:accept { element app:accept {
appCommonAttributes, appCommonAttributes,
( appTypeValue? ) ( appTypeValue? )
} }
appTypeValue = ( "entry" | media-type |entry-or-media-type ) appTypeValue = ( "entry" | media-type |entry-or-media-type )
media-type = xsd:string { pattern = "entry,(.+/.+,?)*" } media-type = xsd:string { pattern = "entry,(.+/.+,?)*" }
entry-or-media-type = xsd:string { pattern = "(.+/.+,?)*" } entry-or-media-type = xsd:string { pattern = "(.+/.+,?)*" }
8.2.5. The "app:categories" Element 8.3.5. The "app:categories" Element
The "app:categories" element provides a listing of the categories
that can be applied to the members of a Collection. The absence of
an "app:categories" element means that the category handling of a
server is unspecified.
atomCategory =
element atom:category {
atomCommonAttributes,
attribute term { text },
attribute scheme { atomURI }?,
attribute label { text }?,
undefinedContent
}
appInlineCategories =
element app:categories {
attribute fixed { "yes" | "no" }?,
attribute scheme { atomURI }?,
(atomCategory*)
}
appOutOfLineCategories =
element app:categories {
attribute href { atomURI },
undefinedContent
}
appCategories = appInlineCategories | appOutOfLineCategories The "app:categories" element provides a list of the categories that
can be applied to the members of a Collection. See Section 7.2.1 for
the detailed definition of app:categories.
The app:categories element MAY contain a "fixed" attribute, with a The server MAY reject attempts to create or update members whose
value of either "yes" or "no", indicating whether or not the listing categories are not listed in the Collection Document. Collections
of categories is considered to be a fixed, or closed set. The that indicate the category set is open SHOULD NOT reject otherwise
absence of the "fixed" attribute is equivalent to the presence of a acceptable members whose categories are not listed by the Collection.
"fixed" attribute with a value of "no". Collections that indicate a
fixed set MAY reject members that include categories not specified in
the provided listing. Collections that indicate an open set SHOULD
NOT reject otherwise acceptable members whose categories are not
present in the provided list.
The app:categories element MAY contain an "href" attribute, whose The absence of an "app:categories" element means that the category
value MUST be an IRI reference identifying a Category Document. If handling of the Collection is unspecified.
the "href" attribute is provided, the app:categories element MUST be
empty and the "fixed" and "scheme" attributes MUST NOT be present.
9. Creating and Editing Resources 9. Creating and Editing Resources
9.1. Member URIs 9.1. Member URIs
The Member URI supports retrieving, updating and deleting the The Member URI allows clients to retrieve, update and delete a Member
resource using HTTP GET, PUT and DELETE. Retrieval and updating of Resource using HTTP's GET, PUT and DELETE methods. As their name
Member Entry Resources are done by exchanging Atom Entry indicates, Entry Resources have Atom Entry documents as
representations. representations.
Member Entry URIs appear in two places. First, they are returned in Member URIs appear in two places. They are returned in a Location
a Location header after successful resource creation using POST, as header after successful resource creation using POST, as described in
described below. Second, they appear in the Entries of a Collection Section 9.2 below. They can also appear in a Collection feed's
document as atom:link elements with a link relation of "edit". entries, as atom:link elements with a link relation of "edit".
Each Member Entry SHOULD contain such an atom:link element providing A Member Entry SHOULD contain such an atom:link element with a link
its Member Entry URI. relation of "edit", which indicates the Member URI.
9.2. Creating resources with POST 9.2. Creating resources with POST
To add members to a Collection, clients send POST requests to the URI To add members to a Collection, clients send POST requests to the URI
of a Collection. Successful member creation is normally indicated of the Collection.
with a 201 ("Created") response code. Collections MAY generate a
response with a status code of 415 ("Unsupported Media Type") to
indicate that the media-type of the POSTed entity is not allowed or
supported by the Collection.
When a Member Resource is created in the Collection which received
the POST, its Member Entry URI MUST be returned in an HTTP Location
header.
When the server generates a response with a status code of 201
("Created"), it SHOULD also return a response body, which if
provided, MUST be an Atom Entry Document representing the newly-
created resource.
Successful member creation is indicated with a 201 ("Created")
response code. When the Collection responds with a status code of
201 ("Created"), it SHOULD also return a response body, which MUST be
an Atom Entry Document representing the newly-created resource.
Since the server is free to alter the POSTed Entry, for example by Since the server is free to alter the POSTed Entry, for example by
changing the content of the "id" element, returning the Entry as changing the content of the "atom:id" element, returning the Entry
described in the previous paragraph can be useful to the client, can be useful to the client, enabling it to correlate the client and
enabling it to correlate the client and server views of the new server views of the new Entry.
Entry.
If the POST request contained an Atom Entry Document, and the When a Member Resource is created, its Member Entry URI MUST be
returned in a Location header in the Collections's response.
If the creation request contained an Atom Entry Document, and the
subsequent response from the server contains a Content-Location subsequent response from the server contains a Content-Location
header that matches the Location header character-for-character, then header that matches the Location header character-for-character, then
the client is authorized to interpret the response entity as being the client is authorized to interpret the response entity as being
the representation of the newly created Entry. Without a matching the representation of the newly created Entry. Without a matching
Content-Location header the client MUST NOT assume the returned Content-Location header the client MUST NOT assume the returned
entity is a complete representation of the created resource. entity is a complete representation of the created resource.
The request body sent with the POST need not be an Atom Entry. For The request body sent with the POST need not be an Atom Entry. For
example, it might be a picture, or a movie. For a discussion of the example, it might be a picture, or a movie. Collections MAY return a
issues in POSTing such content, see Section 9.5. response with a status code of 415 ("Unsupported Media Type") to
indicate that the media-type of the POSTed entity is not allowed or
supported by the Collection. For a discussion of the issues in
creating such content, see Section 9.6.
9.2.1. Example 9.2.1. Example
Below, the client sends a POST request containing an Atom Entry Below, the client sends a POST request containing an Atom Entry
representation to the URI of the Collection: representation to the URI of the Collection:
POST /myblog/entries HTTP/1.1 POST /myblog/entries HTTP/1.1
Host: example.org Host: example.org
User-Agent: Thingio/1.0 User-Agent: Thingio/1.0
Authorization: Basic ZGFmZnk6c2VjZXJldA== Authorization: Basic ZGFmZnk6c2VjZXJldA==
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<entry xmlns="http://www.w3.org/2005/Atom"> <entry xmlns="http://www.w3.org/2005/Atom">
<title>Atom-Powered Robots Run Amok</title> <title>Atom-Powered Robots Run Amok</title>
<id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id> <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
<updated>2003-12-13T18:30:02Z</updated> <updated>2003-12-13T18:30:02Z</updated>
<author><name>John Doe</name></author> <author><name>John Doe</name></author>
<content>Some text.</content> <content>Some text.</content>
</entry> </entry>
The server signals a successful creation with a status code of 201. The server signals a successful creation with a status code of 201.
The response includes a Location: header indicating the Member Entry The response includes a Location: header indicating the Member Entry
URI of the Atom Entry and a representation of that Entry in the body URI of the Atom Entry, and a representation of that Entry in the body
of the response. of the response.
HTTP/1.1 201 Created HTTP/1.1 201 Created
Date: Fri, 7 Oct 2005 17:17:11 GMT Date: Fri, 7 Oct 2005 17:17:11 GMT
Content-Length: nnn Content-Length: nnn
Content-Type: application/atom+xml; charset="utf-8" Content-Type: application/atom+xml; charset="utf-8"
Location: http://example.org/edit/first-post.atom Location: http://example.org/edit/first-post.atom
<?xml version="1.0"?> <?xml version="1.0"?>
<entry xmlns="http://www.w3.org/2005/Atom"> <entry xmlns="http://www.w3.org/2005/Atom">
<title>Atom-Powered Robots Run Amok</title> <title>Atom-Powered Robots Run Amok</title>
<id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id> <id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
<updated>2003-12-13T18:30:02Z</updated> <updated>2003-12-13T18:30:02Z</updated>
<author><name>John Doe</name></author> <author><name>John Doe</name></author>
<content>Some text.</content> <content>Some text.</content>
<link rel="edit" <link rel="edit"
href="http://example.org/edit/first-post.atom"/> href="http://example.org/edit/first-post.atom"/>
</entry> </entry>
The created Entry returned by the server might not match the Entry
POSTed by the client. A server MAY change the values of various The Entry created and returned by the Collection might not match the
elements in the Entry such as the atom:id, atom:updated and atom: Entry POSTed by the client. A server MAY change the values of
author values and MAY choose to remove or add other elements and various elements in the Entry, such as the atom:id, atom:updated and
attributes, or change element and attribute values. atom:author values, and MAY choose to remove or add other elements
and attributes, or change element content and attribute values.
9.3. Updating Resources with PUT 9.3. Updating Resources with PUT
To update a resource, clients send PUT requests to its Member URI, as To update a Member Resource, clients send PUT requests to its Member
specified in [RFC2616]. URI, as specified in [RFC2616].
To avoid unintentional loss of data when editing Member Entries or To avoid unintentional loss of data when editing Member Entries or
Media Link Entries, Atom Protocol clients SHOULD preserve all Media Link Entries, Atom Protocol clients SHOULD preserve all
metadata that has not been intentionally modified, including unknown metadata that has not been intentionally modified, including unknown
foreign markup as defined in Section 6 of [RFC4287]. foreign markup as defined in Section 6 of [RFC4287].
9.4. Deleting Resources with DELETE 9.4. Deleting Resources with DELETE
To delete a resource, clients send DELETE requests to its Member URI, To delete a Member Resource, clients send DELETE requests to its
as specified in [RFC2616]. For Media Resources, deletion of a Media Member URI, as specified in [RFC2616]. For a Media Resource, the
Link Entry SHOULD result in the deletion of the associated Media deletion of its Media Link Entry SHOULD result in the deletion of the
Resource. Media Resource.
9.5. Media Resources and Media Link Entries 9.5. Caching and entity tags
Implementers are advised to pay attention to cache controls, and to
make use of the mechanisms available in HTTP to make editing resource
easier, in particular entity-tags as outlined in
[W3C.NOTE-detect-lost-update-19990510]. Clients are not assured to
receive the most recent representations of Collection Members using
GET if the server is authorizing intermediaries to cache them.
9.5.1. Example
Below, the client creates a Member Entry using POST:
POST /myblog/entries HTTP/1.1
Host: example.org
Authorization: Basic ZGFmZnk6c2VjZXJldA==
Content-Type: application/atom+xml;type=entry
Content-Length: nnn
Slug: First Post
<?xml version="1.0" ?>
<entry xmlns="http://www.w3.org/2005/Atom">
<title>Atom-Powered Robots Run Amok</title>
<id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
<updated>2007-02-123T17:09:02Z</updated>
<author><name>Captain Lansing</name></author>
<content>It's something moving... solid metal</content>
</entry>
The server signals a successful creation with a status code of 201,
and returns an ETag header in the response. Because in this case the
server returned a Content-Location and Location header with the same
value, the returned Entry representation can be understood to be
complete (see Section 9.2) and thus the ETag entity value can be also
be used.
HTTP/1.1 201 Created
Date: Fri, 23 Feb 2007 21:17:11 GMT
Content-Length: nnn
Content-Type: application/atom+xml;type=entry
Location: http://example.org/edit/first-post.atom
Content-Location: http://example.org/edit/first-post.atom
ETag: "e180ee84f0671b1"
<?xml version="1.0" ?>
<entry xmlns="http://www.w3.org/2005/Atom">
<title>Atom-Powered Robots Run Amok</title>
<id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
<updated>2007-02-123T17:09:02Z</updated>
<author><name>Captain Lansing</name></author>
<content>It's something moving... solid metal</content>
</entry>
The client can if it wishes use the returned ETag value to later
construct a "Conditional GET" as defined in [RFC2616]. In this case,
prior to editing the client sends the ETag value for the Member using
the If-None-Match: header.
GET /edit/first-post.atom HTTP/1.1
Host: example.org
Authorization: Basic ZGFmZnk6c2VjZXJldA==
If-None-Match: "e180ee84f0671b1"
If the Entry has not been modified, the server (or an intermediary
cache) can return a status code of 304 (Not Modified). This allows
the client to determine it still has the most recent representation
of the Entry at the time of editing.
HTTP/1.1 304 Not Modified
Date: Sat, 24 Feb 2007 13:17:11 GMT
ETag: "e180ee84f0671b1"
After editing, the client can PUT the updated Entry and send the ETag
entity value in an If-Match header, informing the server to accept
the entry on the condition the entity value sent still matches the
server's.
PUT /edit/first-post.atom HTTP/1.1
Host: example.org
Authorization: Basic ZGFmZnk6c2VjZXJldA==
Content-Type: application/atom+xml;type=entry
Content-Length: nnn
If-Match: "e180ee84f0671b1"
<?xml version="1.0" ?>
<entry xmlns="http://www.w3.org/2005/Atom">
<title>Atom-Powered Robots Run Amok</title>
<id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</id>
<updated>2007-02-24T16:34:06Z</updated>
<author><name>Captain Lansing</name></author>
<content>Update: it's a hoax!</content>
</entry>
The server however has since received a more recent update than the
client's, and responds with a status code of 412 (Precondition
Failed).
HTTP/1.1 412 Precondition Failed
Date: Sat, 24 Feb 2007 16:34:11 GMT
ETag: "r34rrt84f0671b22"
This informs the client that the server has a more recent version of
the Entry and will not allow the update.
9.6. Media Resources and Media Link Entries
A client can POST a media type other than application/atom+xml to a A client can POST a media type other than application/atom+xml to a
Collection. Such a request always creates two new resources - one Collection. Such a request always creates two new resources - one
that corresponds to the entity sent in the request, called the Media that corresponds to the entity sent in the request, called the Media
Resource, and an associated Member Entry, called the Media Link Resource, and an associated Member Entry, called the Media Link
Entry. Media Link Entries are represented as Atom Entries. The Entry. Media Link Entries are represented as Atom Entries and appear
server can signal the media types it will accept via the "accept" in the Collection.
element in the Service Document (Section 8.2.4).
The Media Link Entry contains the IRI of, and metadata about, the The Media Link Entry contains the metadata and IRI of the (perhaps
(perhaps non-textual) Media Resource. The Media Link Entry makes the non-textual) Media Resource. The Media Link Entry thus makes the
metadata about the Media Resource separately available for retrieval metadata about the Media Resource separately available for retrieval
and update. and update.
The server can signal the media types it will accept using the
"accept" element in the Service Document as specified in
Section 8.3.4.
Successful responses to creation requests MUST include the URI of the Successful responses to creation requests MUST include the URI of the
Media Link Entry in the Location header. The Media Link Entry SHOULD Media Link Entry in the Location header. The Media Link Entry SHOULD
contain an atom:link element with a link relation of "edit-media" contain an atom:link element with a link relation of "edit-media"
that contains the Media Resource IRI. The Media Link Entry MUST have that contains the Media Resource IRI. The Media Link Entry MUST have
an "atom:content" element with a "src" attribute. The value of the an "atom:content" element with a "src" attribute. The value of the
"src" attribute is an IRI of the newly created Media Resource. It is "src" attribute is an IRI for the newly created Media Resource. It
OPTIONAL that the IRI of the "src" attribute on the atom:content is OPTIONAL that the IRI of the "src" attribute on the atom:content
element be the same as the Media Resource IRI. For example, the element be the same as the Media Resource IRI. For example, the
"src" attribute value might instead be a link into a static cache or "src" attribute value might instead be a link into a static cache or
content distribution network and not the Media Resource IRI. content distribution network and not the Media Resource IRI.
Implementers are asked to note that according to the requirements of Implementers are asked to note that according to the requirements of
[RFC4287], Entries, and thus Media Link Entries, MUST contain an [RFC4287], Entries, and thus Media Link Entries, MUST contain an
atom:summary element. Upon successful creation of a Media Link atom:summary element. Upon successful creation of a Media Link
Entry, a server MAY choose to populate the atom:summary element (as Entry, a server MAY choose to populate the atom:summary element (as
well as any other required elements such as atom:id, atom:author and well as any other required elements such as atom:id, atom:author and
atom:title) with content derived from the POSTed entity or from any atom:title) with content derived from the POSTed entity or from any
skipping to change at page 27, line 27 skipping to change at page 29, line 34
media type. It does not specify any request semantics or server media type. It does not specify any request semantics or server
behavior in the case where the POSTed media-type is "application/ behavior in the case where the POSTed media-type is "application/
atom+xml" but the body is something other than an Atom Entry. In atom+xml" but the body is something other than an Atom Entry. In
particular, what happens on POSTing an Atom Feed Document to a particular, what happens on POSTing an Atom Feed Document to a
Collection using the "application/atom+xml" media type is undefined. Collection using the "application/atom+xml" media type is undefined.
The Atom Protocol does not specify a means to create multiple The Atom Protocol does not specify a means to create multiple
representations of the same resource (for example a PNG and a JPG of representations of the same resource (for example a PNG and a JPG of
the same image) on creation or update. the same image) on creation or update.
9.5.1. Examples 9.6.1. Examples
Below, the client sends a POST request containing a PNG image to the Below, the client sends a POST request containing a PNG image to the
URI of a Collection that accepts PNG images: URI of a Collection that accepts PNG images:
POST /media/ HTTP/1.1 POST /media/ HTTP/1.1
Host: example.org Host: example.org
Content-Type: image/png Content-Type: image/png
Slug: The Beach Slug: The Beach
Authorization: Basic ZGFmZnk6c2VjZXJldA== Authorization: Basic ZGFmZnk6c2VjZXJldA==
Content-Length: nnn Content-Length: nnn
...binary data... ...binary data...
The server signals a successful creation with a status code of 201. The server signals a successful creation with a status code of 201.
The response includes a Location header indicating the Member URI of The response includes a Location header indicating the Member URI of
the Media Link Entry and a representation of that entry in the body the Media Link Entry and a representation of that entry in the body
of the response. The Media Link Entry includes a content element of the response. The Media Link Entry includes a content element
with a src attribute. It also contains a link using the link with a src attribute. It also contains a link with a link relation
relation "edit-media" specifying the IRI to be used for modifying the of "edit-media", specifying the IRI to be used for modifying the
Media Resource. Media Resource.
HTTP/1.1 201 Created HTTP/1.1 201 Created
Date: Fri, 7 Oct 2005 17:17:11 GMT Date: Fri, 7 Oct 2005 17:17:11 GMT
Content-Length: nnn Content-Length: nnn
Content-Type: application/atom+xml; charset="utf-8" Content-Type: application/atom+xml; charset="utf-8"
Location: http://example.org/media/edit/the_beach.atom Location: http://example.org/media/edit/the_beach.atom
<?xml version="1.0"?> <?xml version="1.0"?>
<entry xmlns="http://www.w3.org/2005/Atom"> <entry xmlns="http://www.w3.org/2005/Atom">
skipping to change at page 32, line 40 skipping to change at page 35, line 40
href="http://example.org/blog/edit/a-day-at-the-beach.atom"/> href="http://example.org/blog/edit/a-day-at-the-beach.atom"/>
<link rel="alternate" type="application/xhtml+xml" <link rel="alternate" type="application/xhtml+xml"
href="http://example.org/blog/a-day-at-the-beach.xhtml"/> href="http://example.org/blog/a-day-at-the-beach.xhtml"/>
</entry> </entry>
Note that the returned Entry contains a link with a relation of Note that the returned Entry contains a link with a relation of
"alternate" that points to the associated XHTML page that was "alternate" that points to the associated XHTML page that was
created. This is not required by this specification, but is included created. This is not required by this specification, but is included
to show the kinds of changes a server may make to an Entry. to show the kinds of changes a server may make to an Entry.
9.6. The Slug: Header 9.7. The Slug: Header
Slug is a HTTP entity-header whose value is a short name that, when Slug is a HTTP entity-header that when accompanying a POST to a
accompanying a POST to a Collection, constitutes a request by the Collection, constitutes a request by the client that its value be
client that its value be used as part of the URI for the to-be- used as part of the URI for the to-be-created Member Resource.
created Member Resource.
When POSTing an entity to a Collection to add a new Member, the Servers MAY use the value of the Slug header when creating the Member
server MAY use this information when creating the Member URI of the URI of the newly-created resource, for instance by using some or all
newly-created resource, for instance by using some or all of the of the words in the value for the last URI segment. Servers MAY also
words in the last URI segment. It MAY also use it when creating the use the value when creating the atom:id or as the title of a Media
atom:id or as the title of a Media Link Entry (see Section 9.5.). Link Entry (see Section 9.6.).
Servers MAY ignore the Slug entity-header and MAY alter its value Servers MAY choose to ignore the Slug entity-header and MAY alter the
before using it. For example, the server MAY filter out some value before using it. For instance, a server might filter out some
characters or replace accented letters with non-accented ones, spaces characters or replace accented letters with non-accented ones,
with underscores, etc. replace spaces with underscores, change case, and so on.
9.6.1. Slug: Header syntax 9.7.1. Slug: Header syntax
The syntax of this header MUST conform to the augmented BNF grammar The syntax of this header MUST conform to the augmented BNF grammar
in section 2.1 of the HTTP/1.1 specification [RFC2616]. The TEXT in section 2.1 of the HTTP/1.1 specification [RFC2616]. The TEXT
rule is described in section 2.2 of the same document. rule is described in section 2.2 of the same document.
Slug = "Slug" ":" *TEXT Slug = "Slug" ":" *TEXT
Clients MAY send non-ASCII characters in the Slug entity-header, Clients MAY send non-ASCII characters in the Slug entity-header,
which they MUST encode using "encoded-words", as defined in which they MUST encode using "encoded-words", as defined in
[RFC2047]. Servers SHOULD treat the slug as [RFC2047] encoded if it [RFC2047]. Servers SHOULD treat the slug as [RFC2047] encoded if it
matches the "encoded-words" production. matches the "encoded-words" production.
9.6.2. Example 9.7.2. Example
Here is an example of the Slug: header that uses the encoding rules Here is an example of the Slug: header that uses the encoding rules
of [RFC2047]. of [RFC2047].
POST /myblog/entries HTTP/1.1 POST /myblog/entries HTTP/1.1
Host: example.org Host: example.org
Content-Type: image/png Content-Type: image/png
Slug: =?iso-8859-1?q?The_Beach?= Slug: =?iso-8859-1?q?The_Beach?=
Authorization: Basic ZGFmZnk6c2VjZXJldA== Authorization: Basic ZGFmZnk6c2VjZXJldA==
Content-Length: nnn Content-Length: nnn
...binary data... ...binary data...
See Section 9.2.1 for an example of the Slug: header applied to the See Section 9.2.1 for an example of the Slug: header applied to the
creation of a Member Entry Resource. creation of an Entry Resource.
10. Listing Collections 10. Listing Collections
Collection Resources MUST provide representations in the form of Atom Collection Resources MUST provide representations in the form of Atom
Feed documents whose Entries contain the IRIs of the Members in the Feed documents whose Entries contain the IRIs of the Members in the
Collection. No structural distinction is made between Collection Collection. No structural distinction is made between Collection
Feeds and other kinds of Feeds - a Feed might act both as a 'public' Feeds and other kinds of Feeds - a Feed might act both as a 'public'
feed for subscription purposes and as a Collection Feed. feed for subscription purposes and as a Collection Feed.
Each Entry in the Feed Document SHOULD have an atom:link element with Each Entry in the Feed Document SHOULD have an atom:link element with
a relation of "edit" (See Section 11.1). a relation of "edit" (See Section 11.1).
The Entries in the returned Atom Feed SHOULD be ordered by their The Entries in the returned Atom Feed SHOULD be ordered by their
"atom:updated" property, with the most recently updated Entries "atom:updated" property, with the most recently updated Entries
coming first in the document order. Clients SHOULD be constructed in coming first in the document order. Since the Atom Syndication
consideration of the fact that changes which do not alter the atom: Format states that the value of atom:updated is altered when the
changes to an Entry are something that "the publisher considers
significant", clients SHOULD be constructed in consideration of the
fact that changes which do not result in alterations to the atom:
updated value of an Entry will not affect the position of the Entry updated value of an Entry will not affect the position of the Entry
in a Collection. That is, the Atom Syndication Format states that in a Collection. The atom:updated value is not equivalent to the
the value of atom:updated is altered when the changes to an Entry are HTTP Last-Modified: header and can not be used to determine the
something that "the publisher considers significant." The atom: freshness of cached responses.
updated value is not equivalent to the HTTP Last-Modified: header and
can not be used to determine the freshness of cached responses.
Clients MUST NOT assume that an Atom Entry returned in the Feed is a Clients MUST NOT assume that an Atom Entry returned in the Feed is a
full representation of a Member Entry Resource and SHOULD perform a full representation of an Entry Resource and SHOULD perform a GET on
GET on the URI of the Member Entry before editing. the URI of the Member Entry before editing it. See Section 9.5 for a
discussion on the implications of cache control directives when
obtaining entries.
10.1. Collection Paging 10.1. Collection partial lists
Collections can contain large numbers of resources. A naive client Collections can contain large numbers of resources. A client such as
such as a web spider or web browser could be overwhelmed if the a web spider or web browser might be overwhelmed if the response to a
response to a GET contained every Entry in the Collection, and the GET contained every Entry in a Collection - in turn the server might
server would waste large amounts of bandwidth and processing time on also waste bandwidth and processing time on generating a response
clients unable to handle the response. For this reason, servers MAY that cannot be handled. For this reason, servers MAY respond to
return a partial listing of the most recently updated Member Collection GET requests with a feed document containing a 'partial
Resources. Such partial feed documents MUST have an atom:link with a list' of the Collection's members, which also links to the next
"next" relation whose "href" value is the URI of the next partial partial list feed if it exists. The first such partial list returned
listing of the Collection (the next most recently updated Member MUST contain the most recently updated member resources and MUST have
Resources) where it exists. This is called "Collection paging". an atom:link with a "next" relation whose "href" value is the URI of
the next partial list of the Collection. This next partial list will
contain the next most recently updated set of Member Resources (and
an atom:link to the following partial list if it exists).
The returned Atom Feed MAY contain a subset the Member Entries for a In addition, partial list feeds MAY contain link elements with "rel"
Collection. In addition, the Atom Feed document MAY contain link attribute values of "next", "previous", "first" and "last" that can
elements with "rel" attribute values of "next", "previous", "first" be used to navigate through the complete set of entries in the
and "last" that can be used to navigate through the complete set of Collection.
matching Entries.
For instance, suppose a client is supplied the URI For instance, suppose a client is supplied the URI
"http://example.org/entries/go" of a Collection of Member entries, "http://example.org/entries/go" of a Collection of Member entries,
where the server as a matter of policy avoids generating feed where the server as a matter of policy avoids generating feed
documents containing more than 10 Entries. The Atom Feed document documents containing more than 10 Entries. The Atom Feed document
for the Collection will then represent the first 'page' in a set of for the Collection will then represent the first partial list of a
10 linked feed documents. The "first" relation will reference the set of 10 linked feed documents. The "first" relation will reference
initial feed document in the set and the "last" relation references the initial feed document in the set and the "last" relation
the final Atom Feed Document in the set. Within each document, the references the final Atom Feed Document in the set. Within each
"next" and "previous" link relations reference the preceding and document, the "next" and "previous" link relations reference the
subsequent documents. preceding and subsequent documents.
<feed xmlns="http://www.w3.org/2005/Atom"> <feed xmlns="http://www.w3.org/2005/Atom">
<link rel="first" <link rel="first"
href="http://example.org/entries/go" /> href="http://example.org/entries/go" />
<link rel="next" <link rel="next"
href="http://example.org/entries/2" /> href="http://example.org/entries/2" />
<link rel="last" <link rel="last"
href="http://example.org/entries/10" /> href="http://example.org/entries/10" />
... ...
</feed> </feed>
The "next" and "previous" link elements for the feed 'page' located The "next" and "previous" link elements for the partial list feed
at "http://example.org/entries/2" would look like this: located at "http://example.org/entries/2" would look like this:
<feed xmlns="http://www.w3.org/2005/Atom"> <feed xmlns="http://www.w3.org/2005/Atom">
<link rel="first" <link rel="first"
href="http://example.org/entries/go" /> href="http://example.org/entries/go" />
<link rel="previous" <link rel="previous"
href="http://example.org/entries/go" /> href="http://example.org/entries/go" />
<link rel="next" <link rel="next"
href="http://example.org/entries/3" /> href="http://example.org/entries/3" />
<link rel="last" <link rel="last"
href="http://example.org/entries/10" /> href="http://example.org/entries/10" />
... ...
</feed> </feed>
10.2. The "app:edited" Element 10.2. The "app:edited" Element
The "app:edited" element is a Date construct as defined by [RFC4287] The "app:edited" element is a Date construct as defined by [RFC4287]
whose value indicates the most recent instant in time when an Entry whose content indicates the last time an Entry was edited. If the
was edited, including when created. Atom Entry elements in entry has not been edited yet, the content indicates the time it was
Collection documents SHOULD contain one "app:edited" element, and created. Atom Entry elements in Collection documents SHOULD contain
MUST NOT contain more than one. one "app:edited" element, and MUST NOT contain more than one.
appEdited = element app:edited ( atomDateConstruct ) appEdited = element app:edited ( atomDateConstruct )
The server SHOULD change the value of this element every time a The server SHOULD change the value of this element every time a
Collection Member Resource or an associated Media Resource has been Collection Member Resource or an associated Media Resource has been
edited. edited.
11. Atom Format Link Relation Extensions 11. Atom Format Link Relation Extensions
11.1. The "edit" Link Relation 11.1. The "edit" Link Relation
This specification adds the value "edit" to the Atom Registry of Link This specification adds the value "edit" to the Atom Registry of Link
Relations (see section 7.1 of [RFC4287]). The value of "edit" Relations (see section 7.1 of [RFC4287]). The value of "edit"
skipping to change at page 37, line 7 skipping to change at page 41, line 7
relations in the same Entry reference the same resource. If a client relations in the same Entry reference the same resource. If a client
encounters multiple "edit-media" link relations in an Entry then it encounters multiple "edit-media" link relations in an Entry then it
SHOULD choose a link based on the client preferences for "type" and SHOULD choose a link based on the client preferences for "type" and
"hreflang". If a client encounters multiple "edit-media" link "hreflang". If a client encounters multiple "edit-media" link
relations in an Entry and has no preference based on the "type" and relations in an Entry and has no preference based on the "type" and
"hreflang" attributes then the client SHOULD pick the first "edit- "hreflang" attributes then the client SHOULD pick the first "edit-
media" link relation in document order. media" link relation in document order.
12. The Atom Format Type Parameter 12. The Atom Format Type Parameter
The Atom Syndication Format (RFC 4287) defines the 'application/ The Atom Syndication Format (RFC 4287) defines the "application/
atom+xml' media type to identify both Atom Feed and Atom Entry atom+xml" media type to identify both Atom Feed and Atom Entry
Documents. Implementation experience has demonstrated that Atom Feed Documents. Implementation experience has demonstrated that Atom Feed
and Entry Documents can have different processing models and that and Entry Documents can have different processing models and that
there are situations where they need to be differentiated. This there are situations where they need to be differentiated. This
document defines an optional 'type' parameter used to differentiate document defines an optional "type" parameter used to differentiate
the two types of Atom documents. the two types of Atom documents.
12.1. The 'type' parameter 12.1. The 'type' parameter
This document defines a new "type" parameter for use with the This document defines a new "type" parameter for use with the
'application/atom+xml' media type. "application/atom+xml" media type:
type = "entry" / "feed" type = "entry" / "feed"
Neither the parameter name nor its value are case sensitive. Neither the parameter name nor its value are case sensitive.
The value 'entry' indicates that the media type identifies an Atom The value "entry" indicates that the media type identifies an Atom
Entry Document. The root element of the document MUST be atom:entry. Entry Document. The root element of the document MUST be atom:entry.
The value 'feed' indicates that the media type identifies an Atom The value "feed" indicates that the media type identifies an Atom
Feed Document. The root element of the document MUST be atom:feed. Feed Document. The root element of the document MUST be atom:feed.
If not specified, the type is assumed to be unspecified, requiring If not specified, the type is assumed to be unspecified, requiring
Atom processors to examine the root element to determine the type of Atom processors to examine the root element to determine the type of
Atom document. Atom document.
12.1.1. Conformance 12.1.1. Conformance
New specifications MAY require that the type parameter be used to New specifications MAY require that the type parameter be used to
identify the Atom Document type. Producers of Atom Entry Documents identify the Atom Document type. Producers of Atom Entry Documents
SHOULD use the type parameter regardless of whether or not it is SHOULD use the type parameter regardless of whether or not it is
required. Producers of Atom Feed Documents MAY use the parameter. required. Producers of Atom Feed Documents MAY use the parameter.
Atom processors that do not recognize the 'type' parameter MUST Atom processors that do not recognize the "type" parameter MUST
ignore its value and examine the root element to determine the ignore its value and examine the root element to determine the
document type. document type.
Atom processors that do recognize the parameter SHOULD detect and Atom processors that do recognize the "type" parameter SHOULD detect
report inconsistencies between the parameter's value and the actual and report inconsistencies between the parameter's value and the
type of the document's root element. actual type of the document's root element.
13. Atom Publishing Controls 13. Atom Publishing Controls
This specification defines an Atom Format Structured Extension, as This specification defines an Atom Format Structured Extension, as
defined in Section 6 of [RFC4287], for publishing control within the defined in Section 6 of [RFC4287], for publishing control within the
"http://purl.org/atom/app#" namespace. "http://purl.org/atom/app#" namespace.
13.1. The "app:control" Element 13.1. The "app:control" Element
namespace app = "http://purl.org/atom/app#" namespace app = "http://purl.org/atom/app#"
skipping to change at page 38, line 40 skipping to change at page 42, line 40
The app:control element and its child elements MAY be included in The app:control element and its child elements MAY be included in
Atom Feed or Entry Documents. Atom Feed or Entry Documents.
The app:control element can contain an optional "app:draft" element The app:control element can contain an optional "app:draft" element
as defined below, and can contain extension elements as defined in as defined below, and can contain extension elements as defined in
Section 6 of [RFC4287]. Section 6 of [RFC4287].
13.1.1. The "app:draft" Element 13.1.1. The "app:draft" Element
The inclusion of the app:draft element represents a request by the
client to control the visibility of a Member Resource. Server
support is optional and thus the app:draft element MAY be ignored by
the server.
The number of app:draft elements in app:control MUST be zero or one. The number of app:draft elements in app:control MUST be zero or one.
Its value MUST be one of "yes" or "no". A value of "no" indicates a The content of an app:draft element MUST be one of "yes" or "no". If
client request that the Member Resource be made publicly visible. If the element contains "no" this indicates a client request that the
the app:draft element is missing then the value MUST be understood to Member Resource be made publicly visible. If the app:draft element
be "no". The inclusion of the app:draft element represents a request is not present then servers that support the extension MUST behave as
by the client to control the visibility of a Member Resource and the though an app:draft element containing "no" was sent.
app:draft element MAY be ignored by the server.
14. Securing the Atom Publishing Protocol 14. Securing the Atom Publishing Protocol
The Atom Publishing Protocol is based on HTTP. Authentication The Atom Publishing Protocol is based on HTTP. Authentication
requirements for HTTP are covered in Section 11 of [RFC2616]. requirements for HTTP are covered in Section 11 of [RFC2616].
The use of authentication mechanisms to prevent POSTing or editing by The use of authentication mechanisms to prevent POSTing or editing by
unknown or unauthorized clients is RECOMMENDED but not required. unknown or unauthorized clients is RECOMMENDED but not required.
When authentication is not used, clients and servers are vulnerable When authentication is not used, clients and servers are vulnerable
to trivial spoofing, denial of service and defacement attacks, to trivial spoofing, denial of service and defacement attacks,
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server operator. Clients are likely to face authentication schemes server operator. Clients are likely to face authentication schemes
that vary across server deployments. At a minimum, client and server that vary across server deployments. At a minimum, client and server
implementations MUST be capable of being configured to use HTTP Basic implementations MUST be capable of being configured to use HTTP Basic
Authentication [RFC2617] in conjunction with a TLS connection as Authentication [RFC2617] in conjunction with a TLS connection as
specified by [RFC2818]. See [RFC4346] for more information on TLS. specified by [RFC2818]. See [RFC4346] for more information on TLS.
The choice of authentication mechanism will impact interoperability. The choice of authentication mechanism will impact interoperability.
The minimum level of security referenced above (Basic Authentication The minimum level of security referenced above (Basic Authentication
with TLS) is considered good practice for Internet applications at with TLS) is considered good practice for Internet applications at
the time of publication of this specification and sufficient for the time of publication of this specification and sufficient for
establishing a baseline for interoperability. Implementers can establishing a baseline for interoperability. Implementers are
investigate and use alternative mechanisms regarded as equivalently encouraged to investigate and use alternative mechanisms regarded as
good or better at the time of deployment. It is RECOMMENDED that equivalently good or better at the time of deployment. It is
clients be implemented in such a way that allows new authentication RECOMMENDED that clients be implemented in such a way that allows new
schemes to be deployed. authentication schemes to be deployed.
Because this protocol uses HTTP response status codes as the primary Because this protocol uses HTTP response status codes as the primary
means of reporting the result of a request, servers are advised to means of reporting the result of a request, servers are advised to
respond to unauthorized or unauthenticated requests using an respond to unauthorized or unauthenticated requests using an
appropriate 4xx HTTP response code (e.g. 401 "Unauthorized" or 403 appropriate 4xx HTTP response code (e.g. 401 "Unauthorized" or 403
"Forbidden") in accordance with [RFC2617]. "Forbidden") in accordance with [RFC2617].
15. Security Considerations 15. Security Considerations
As an HTTP-based protocol, APP is subject to the security As an HTTP-based protocol, APP is subject to the security
skipping to change at page 41, line 14 skipping to change at page 45, line 14
16. IANA Considerations 16. IANA Considerations
16.1. Content-type registration for 'application/atomserv+xml' 16.1. Content-type registration for 'application/atomserv+xml'
An Atom Publishing Protocol Service Document, when serialized as XML An Atom Publishing Protocol Service Document, when serialized as XML
1.0, can be identified with the following media type: 1.0, can be identified with the following media type:
MIME media type name: application MIME media type name: application
MIME subtype name: atomserv+xml MIME subtype name: atomsvc+xml
Mandatory parameters: None. Mandatory parameters: None.
Optional parameters: Optional parameters:
"charset": This parameter has identical semantics to the charset "charset": This parameter has identical semantics to the charset
parameter of the "application/xml" media type as specified in parameter of the "application/xml" media type as specified in
[RFC3023]. [RFC3023].
Encoding considerations: Identical to those of "application/xml" as Encoding considerations: Identical to those of "application/xml" as
described in [RFC3023], section 3.2. described in [RFC3023], section 3.2.
Security considerations: As defined in this specification. Security considerations: As defined in this specification.
[[anchor32: update upon publication]] [[anchor30: update upon publication]]
In addition, as this media type uses the "+xml" convention, it In addition, as this media type uses the "+xml" convention, it
shares the same security considerations as described in [RFC3023], shares the same security considerations as described in [RFC3023],
section 10. section 10.
Interoperability considerations: There are no known interoperability Interoperability considerations: There are no known interoperability
issues. issues.
Published specification: This specification. [[anchor33: update upon Published specification: This specification. [[anchor31: update upon
publication]] publication]]
Applications that use this media type: No known applications Applications that use this media type: No known applications
currently use this media type. currently use this media type.
Additional information: Additional information:
Magic number(s): As specified for "application/xml" in [RFC3023], Magic number(s): As specified for "application/xml" in [RFC3023],
section 3.2. section 3.2.
File extension: .atomsrv File extension: .atomsvc
Fragment identifiers: As specified for "application/xml" in Fragment identifiers: As specified for "application/xml" in
[RFC3023], section 5. [RFC3023], section 5.
Base URI: As specified in [RFC3023], section 6. Base URI: As specified in [RFC3023], section 6.
Macintosh File Type code: TEXT Macintosh File Type code: TEXT
Person and email address to contact for further information: Joe Person and email address to contact for further information: Joe
Gregorio <joe@bitworking.org> Gregorio <joe@bitworking.org>
Intended usage: COMMON Intended usage: COMMON
Author/Change controller: This specification's author(s). Author/Change controller: This specification's author(s).
[[anchor34: update upon publication]] [[anchor32: update upon publication]]
16.2. Content-type registration for 'application/atomcat+xml' 16.2. Content-type registration for 'application/atomcat+xml'
An Atom Publishing Protocol Category Document, when serialized as XML An Atom Publishing Protocol Category Document, when serialized as XML
1.0, can be identified with the following media type: 1.0, can be identified with the following media type:
MIME media type name: application MIME media type name: application
MIME subtype name: atomcat+xml MIME subtype name: atomcat+xml
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Optional parameters: Optional parameters:
"charset": This parameter has identical semantics to the charset "charset": This parameter has identical semantics to the charset
parameter of the "application/xml" media type as specified in parameter of the "application/xml" media type as specified in
[RFC3023]. [RFC3023].
Encoding considerations: Identical to those of "application/xml" as Encoding considerations: Identical to those of "application/xml" as
described in [RFC3023], section 3.2. described in [RFC3023], section 3.2.
Security considerations: As defined in this specification. Security considerations: As defined in this specification.
[[anchor35: update upon publication]] [[anchor33: update upon publication]]
In addition, as this media type uses the "+xml" convention, it In addition, as this media type uses the "+xml" convention, it
shares the same security considerations as described in [RFC3023], shares the same security considerations as described in [RFC3023],
section 10. section 10.
Interoperability considerations: There are no known interoperability Interoperability considerations: There are no known interoperability
issues. issues.
Published specification: This specification. [[anchor36: update upon Published specification: This specification. [[anchor34: update upon
publication]] publication]]
Applications that use this media type: No known applications Applications that use this media type: No known applications
currently use this media type. currently use this media type.
Additional information: Additional information:
Magic number(s): As specified for "application/xml" in [RFC3023], Magic number(s): As specified for "application/xml" in [RFC3023],
section 3.2. section 3.2.
skipping to change at page 43, line 31 skipping to change at page 47, line 31
Base URI: As specified in [RFC3023], section 6. Base URI: As specified in [RFC3023], section 6.
Macintosh File Type code: TEXT Macintosh File Type code: TEXT
Person and email address to contact for further information: Joe Person and email address to contact for further information: Joe
Gregorio <joe@bitworking.org> Gregorio <joe@bitworking.org>
Intended usage: COMMON Intended usage: COMMON
Author/Change controller: This specification's author(s). Author/Change controller: This specification's author(s).
[[anchor37: update upon publication]] [[anchor35: update upon publication]]
16.3. Header field registration for 'SLUG' 16.3. Header field registration for 'SLUG'
Header field: SLUG Header field: SLUG
Applicable protocol: http [RFC2616] Applicable protocol: http [RFC2616]
Status: standard. Status: standard.
Author/Change controller: IETF (iesg@ietf.org) Internet Engineering Author/Change controller: IETF (iesg@ietf.org) Internet Engineering
Task Force Task Force
Specification document(s): draft-ietf-atompub-protocol-13.txt Specification document(s): draft-ietf-atompub-protocol-13.txt
([[anchor38: update on rfc number assignment]]) ([[anchor36: update on rfc number assignment]])
Related information: Related information:
16.4. The Link Relation registration "edit" 16.4. The Link Relation registration "edit"
Attribute Value: edit Attribute Value: edit
Description: An IRI of an editable Member Entry. When appearing Description: An IRI of an editable Member Entry. When appearing
within an atom:entry, the href IRI can be used to retrieve, update within an atom:entry, the href IRI can be used to retrieve, update
and delete the resource represented by that Entry. and delete the resource represented by that Entry.
skipping to change at page 45, line 25 skipping to change at page 49, line 25
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., [RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
Leach, P., Luotonen, A., and L. Stewart, "HTTP Leach, P., Luotonen, A., and L. Stewart, "HTTP
Authentication: Basic and Digest Access Authentication", Authentication: Basic and Digest Access Authentication",
RFC 2617, June 1999. RFC 2617, June 1999.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media [RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media
Types", RFC 3023, January 2001. Types", RFC 3023, January 2001.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005. RFC 3986, January 2005.
[RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource [RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource
Identifiers (IRIs)", RFC 3987, January 2005. Identifiers (IRIs)", RFC 3987, January 2005.
skipping to change at page 46, line 32 skipping to change at page 50, line 30
<http://www.w3.org/TR/2002/REC-xmldsig-core-20020212>. <http://www.w3.org/TR/2002/REC-xmldsig-core-20020212>.
[W3C.REC-xmlenc-core] [W3C.REC-xmlenc-core]
Eastlake, D. and J. Reagle, "XML Encryption Syntax and Eastlake, D. and J. Reagle, "XML Encryption Syntax and
Processing", World Wide Web Consortium Recommendation REC- Processing", World Wide Web Consortium Recommendation REC-
xmlenc-core-20021210, December 2002, xmlenc-core-20021210, December 2002,
<http://www.w3.org/TR/2002/REC-xmlenc-core-20021210>. <http://www.w3.org/TR/2002/REC-xmlenc-core-20021210>.
17.2. Informative References 17.2. Informative References
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RNC] Clark, J., "RELAX NG Compact Syntax", December 2001, <http [RNC] Clark, J., "RELAX NG Compact Syntax", December 2001, <http
://www.oasis-open.org/committees/relax-ng/ ://www.oasis-open.org/committees/relax-ng/
compact-20021121.html>. compact-20021121.html>.
[W3C.NOTE-detect-lost-update-19990510]
Nielsen, H. and D. LaLiberte, "Editing the Web: Detecting
the Lost Update Problem Using Unreserved Checkout", World
Wide Web Consortium NOTE NOTE-detect-lost-update,
May 1999, <http://www.w3.org/1999/04/Editing/>.
[W3C.REC-webarch-20041215] [W3C.REC-webarch-20041215]
Walsh, N. and I. Jacobs, "Architecture of the World Wide Walsh, N. and I. Jacobs, "Architecture of the World Wide
Web, Volume One", W3C REC REC-webarch-20041215, Web, Volume One", W3C REC REC-webarch-20041215,
December 2004. December 2004.
URIs URIs
[1] <http://www.imc.org/atom-protocol/index.html> [1] <http://www.imc.org/atom-protocol/index.html>
Appendix A. Contributors Appendix A. Contributors
The content and concepts within are a product of the Atom community The content and concepts within are a product of the Atom community
and the Atompub Working Group. and the Atompub Working Group.
[[anchor42: chairs to compile a contribution list for 1.0 --dehora]] [[anchor40: chairs to compile a contribution list for 1.0 --dehora]]
Appendix B. RELAX NG Compact Schema Appendix B. RELAX NG Compact Schema
This appendix is informative. This appendix is informative.
The Relax NG schema explicitly excludes elements in the Atom Protocol The Relax NG schema explicitly excludes elements in the Atom Protocol
namespace which are not defined in this revision of the namespace which are not defined in this revision of the
specification. Requirements for Atom Protocol processors specification. Requirements for Atom Protocol processors
encountering such markup are given in Section 6.2 and Section 6.3 of encountering such markup are given in Section 6.2 and Section 6.3 of
[RFC4287]. [RFC4287].
skipping to change at page 55, line 7 skipping to change at page 59, line 7
element * - atom:* { element * - atom:* {
(attribute * { text } (attribute * { text }
| text | text
| anyElement)* | anyElement)*
} }
# EOF # EOF
Appendix C. Revision History Appendix C. Revision History
[[anchor44: This section to be removed upon publication.]] [[anchor42: This section to be removed upon publication.]]
draft-ietf-atompub-protocol-14: typos; removed "The language context
is only significant for elements and attributes declared to be
"Language-Sensitive" by this specification. "; "Successful member
creation is normally indicated with a 201 ("Created") response code."
removed "normally" from that sentence (9.2); Added "Media Link
Entries are represented as Atom Entries and appear in the
Collection." to 9.6; said that an app:accept value of "entry" is
equivalent to "application/atom+xml;type=entry"; double-check spec
terms; Member Entry Resource -> Entry Resource; Added MLE, Entry
Resource and Media Resource terms defs; 6.1 para split; 10.1
collection paging, rewrote for clarity; 13.1.1 app:edited rewrote for
clarity/conflict; text for GETting entries and cache handling; 4:
Typo: "And Media Resources IRIs", s/Resources/Resource/; consensus
call: application/atomsvc+xml, extension is .atomsvc; DRY app:
categories; make it clear the app:draft support is optional whether
or not the value is sent; 9.2: put related ideas together into
paragraphs.; 10: partial list editing; security: use elharos text;
app:edited: tweak text suplied by ari; create a section for
workspaces and move the descriptive text there; Moved rfc2818 to non-
normative references. Added the W3C note on lost updates as a
reference.
draft-ietf-atompub-protocol-13: Added Lisa's verbiage. Folded in draft-ietf-atompub-protocol-13: Added Lisa's verbiage. Folded in
James' Atom Format media type 'type' parameter spec. Updated James' Atom Format media type 'type' parameter spec. Updated
document references to be more consistent, added URLs to some, and document references to be more consistent, added URLs to some, and
shortened up their anchors. Debugged rnc. shortened up their anchors. Debugged rnc.
draft-ietf-atompub-protocol-11: Parts of PaceAppEdited. draft-ietf-atompub-protocol-11: Parts of PaceAppEdited.
PaceSecurityConsiderationsRevised. PaceSecurityConsiderationsRevised.
draft-ietf-atompub-protocol-10: PaceRemoveTitleHeader2, draft-ietf-atompub-protocol-10: PaceRemoveTitleHeader2,
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