--- 1/draft-ietf-atompub-protocol-08.txt 2006-06-29 05:12:20.000000000 +0200 +++ 2/draft-ietf-atompub-protocol-09.txt 2006-06-29 05:12:20.000000000 +0200 @@ -1,19 +1,19 @@ Network Working Group J. Gregorio, Ed. Internet-Draft BitWorking, Inc -Expires: August 5, 2006 B. de hOra, Ed. +Expires: December 25, 2006 B. de hOra, Ed. Propylon Ltd. - February 01, 2006 + June 23, 2006 The Atom Publishing Protocol - draft-ietf-atompub-protocol-08.txt + draft-ietf-atompub-protocol-09.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that @@ -24,21 +24,21 @@ and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. - This Internet-Draft will expire on August 5, 2006. + This Internet-Draft will expire on December 25, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract The Atom Publishing Protocol (APP) is an application-level protocol for publishing and editing Web resources. The protocol is based on HTTP transport of Atom-formatted representations. The Atom format is @@ -67,80 +67,79 @@ 6.1 Referring to Information Items . . . . . . . . . . . . . . 11 6.2 XML Namespace Usage . . . . . . . . . . . . . . . . . . . 11 6.3 Use of xml:base and xml:lang . . . . . . . . . . . . . . . 11 6.4 RELAX NG Schema . . . . . . . . . . . . . . . . . . . . . 12 7. Introspection Documents . . . . . . . . . . . . . . . . . . 13 7.1 Example . . . . . . . . . . . . . . . . . . . . . . . . . 13 7.2 Element Definitions . . . . . . . . . . . . . . . . . . . 14 7.2.1 The "app:service" Element . . . . . . . . . . . . . . 14 7.2.2 The "app:workspace" Element . . . . . . . . . . . . . 14 7.2.3 The "app:collection" Element . . . . . . . . . . . . . 15 - 7.2.4 The "app:member-type" Element . . . . . . . . . . . . 16 + 7.2.4 The "app:accept" Element . . . . . . . . . . . . . . . 16 8. Collections . . . . . . . . . . . . . . . . . . . . . . . . 17 8.1 Creating resources with POST . . . . . . . . . . . . . . . 17 - 8.1.1 Example . . . . . . . . . . . . . . . . . . . . . . . 17 - 8.1.2 Title: Header . . . . . . . . . . . . . . . . . . . . 17 - 8.2 Entry Collections . . . . . . . . . . . . . . . . . . . . 18 - 8.2.1 Editing entries with foreign markup . . . . . . . . . 18 - 8.3 Media Collections . . . . . . . . . . . . . . . . . . . . 18 - 8.3.1 Editing Media Resources . . . . . . . . . . . . . . . 18 - 8.3.2 Editing Media Metadata . . . . . . . . . . . . . . . . 19 - 9. Listing Collections . . . . . . . . . . . . . . . . . . . . 20 - 9.1 Collection Paging . . . . . . . . . . . . . . . . . . . . 20 - 10. Atom Format Link Relation Extensions . . . . . . . . . . . . 22 - 10.1 The "edit" Link Relation . . . . . . . . . . . . . . . . 22 - 11. Atom Publishing Control Extensions . . . . . . . . . . . . . 23 - 11.1 The Atom Publishing Control Namespace . . . . . . . . . 23 - 11.2 The "pub:control" Element . . . . . . . . . . . . . . . 23 - 11.2.1 The "pub:draft" Element . . . . . . . . . . . . . . 23 - 12. Atom Publishing Protocol Example . . . . . . . . . . . . . . 24 - 13. Securing the Atom Protocol . . . . . . . . . . . . . . . . . 26 - 14. Security Considerations . . . . . . . . . . . . . . . . . . 27 - 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . 28 - 16. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 - 16.1 Normative References . . . . . . . . . . . . . . . . . . 30 - 16.2 Informative References . . . . . . . . . . . . . . . . . 31 + 8.2 Example . . . . . . . . . . . . . . . . . . . . . . . . . 17 + 8.3 The 'edit' Link . . . . . . . . . . . . . . . . . . . . . 19 + 8.4 Media Resources and Media Link Entries . . . . . . . . . . 19 + 8.4.1 Title: Header . . . . . . . . . . . . . . . . . . . . 20 + 8.4.2 Example . . . . . . . . . . . . . . . . . . . . . . . 20 + 8.5 Editing Entries with Foreign Markup . . . . . . . . . . . 21 + 9. Listing Collections . . . . . . . . . . . . . . . . . . . . 22 + 9.1 Collection Paging . . . . . . . . . . . . . . . . . . . . 22 + 10. Atom Format Link Relation Extensions . . . . . . . . . . . . 24 + 10.1 The "edit" Link Relation . . . . . . . . . . . . . . . . 24 + 10.2 The "edit-media" Link Relation . . . . . . . . . . . . . 24 + 11. Atom Publishing Control Extensions . . . . . . . . . . . . . 25 + 11.1 The Atom Publishing Control Namespace . . . . . . . . . 25 + 11.2 The "pub:control" Element . . . . . . . . . . . . . . . 25 + 11.2.1 The "pub:draft" Element . . . . . . . . . . . . . . 25 + 12. Securing the Atom Protocol . . . . . . . . . . . . . . . . . 26 + 13. Security Considerations . . . . . . . . . . . . . . . . . . 27 + 14. IANA Considerations . . . . . . . . . . . . . . . . . . . . 28 + 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 + 15.1 Normative References . . . . . . . . . . . . . . . . . . 30 + 15.2 Informative References . . . . . . . . . . . . . . . . . 31 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 32 A. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 33 B. RELAX NG Compact Schema . . . . . . . . . . . . . . . . . . 34 C. Revision History . . . . . . . . . . . . . . . . . . . . . . 37 Intellectual Property and Copyright Statements . . . . . . . 40 1. Introduction The Atom Publishing Protocol is an application-level protocol for publishing and editing Web resources using HTTP [RFC2616] and XML 1.0 [W3C.REC-xml-20040204]. The protocol supports the creation of arbitrary web resources and provides facilities for: - o Collections: Sets of resources, which may be retrieved in whole or + o Collections: Sets of resources, which can be retrieved in whole or in part. o Introspection: Discovering and describing collections. o Editing: Creating, updating and deleting resources. 2. Notational Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. Note: The Introspection Document allows the use of IRIs [RFC3987], as well as URIs [RFC3986]. Every URI is an IRI, so any URI can be used where an IRI is needed. How to map an IRI to a URI is specified in Section 3.1 of Internationalized Resource Identifiers (IRIs) [RFC3987]. 3. Terminology - For convenience, this protocol may be referred to as the "Atom + For convenience, this protocol can be referred to as the "Atom Protocol" or "APP". URI/IRI - A Uniform Resource Identifier and Internationalized Resource Identifier. These terms and the distinction between them are defined in [RFC3986] and [RFC3987]. Note that IRIs are mapped to URIs before dereferencing takes place. Resource - A network-accessible data object or service identified by an IRI, as defined in [RFC2616]. See [W3C.REC-webarch-20041215] for further discussion on resources. @@ -167,27 +166,27 @@ o GET is used to retrieve a representation of a resource or perform a query. o POST is used to create a new, dynamically-named resource. o PUT is used to update a known resource. o DELETE is used to remove a resource. - Along with operations on resources, the Atom Protocol provides list- - based structures, called Collections, for managing and organising + Along with operations on resources the Atom Protocol provides + structures, called Collections, for managing and organising resources, called Members. Collections contain the IRIs of, and - metadata about, their Member resources. For authoring and editing of - resources to commence, an Atom Protocol client can examine - Introspection Documents which represent server-defined groups of - Collections. + metadata about, their Member resources. Atom Protocol clients can + use Introspection documents, which represent server-defined groups of + Collections, to initialize the process of creating and editing + resources. Note that when an IRI is used for resource retrieval over HTTP, the IRI is first converted to a URI according the procedure defined in [RFC3987] section 3.1. The resource that the IRI locates is the same as the one located by the URI obtained after converting the IRI. 5. Protocol Operations 5.1 Retrieving an Introspection Document @@ -222,21 +221,21 @@ 1. The client POSTs a representation of the Member to the URI of the collection. 2. If the Member resource was created successfully, the server responds with a status code of 201 and a Location: header that contains the URI of the newly created resource. 5.3 Editing a Resource - Once a resource has been created and its URI is known, that URI may + Once a resource has been created and its URI is known, that URI can be used to retrieve, update, and delete the resource. 5.3.1 Retrieving a Resource Client Server | | | 1.) GET to Member URI | |------------------------------------------>| | | | 2.) Member Representation | @@ -299,21 +298,21 @@ 2. The server responds with an Atom Feed Document containing the IRIs of the collection members. 5.5 Use of HTTP Response codes The Atom Protocol uses the response status codes defined in HTTP to indicate the success or failure of an operation. Consult the HTTP specification [RFC2616] for detailed definitions of each status code. It is RECOMMENDED that entities contained within HTTP 4xx and 5xx - responses include an explanation of the error using natural language. + responses include a human-readable explanation of the error. 6. XML-related Conventions The Atom Protocol Introspection format is specified in terms of the XML Information Set [W3C.REC-xml-infoset-20040204], serialised as XML 1.0 [W3C.REC-xml-20040204]. Atom Publishing Protocol Documents MUST be well-formed XML. This specification does not define any DTDs for Atom Protocol, and hence does not require them to be "valid" in the sense used by XML. @@ -329,23 +328,32 @@ 6.2 XML Namespace Usage The namespace name [W3C.REC-xml-names-19990114] for the XML format described in this specification is: http://purl.org/atom/app# This specification uses the prefix "app:" for the namespace name. The choice of namespace prefix is not semantically significant. + The "app:" namespace is reserved for future forward-compatible + revisions of the Atom Publishing Protocol. Future versions of this + specification could add new elements and attributes to the markup + vocabulary. Software written to conform to this version of the + specification will not be able to process such markup correctly and, + in fact, will not be able to distinguish it from markup error. For + the purposes of this discussion, unrecognized markup from the Atom + Publishing Protocol vocabulary will be considered "foreign markup". + This specification also uses the prefix "atom:" for "http://www.w3.org/2005/Atom", the namespace name of the Atom - Publishing Format [RFC4287]. + Syndication Format [RFC4287]. 6.3 Use of xml:base and xml:lang XML elements defined by this specification MAY have an xml:base attribute [W3C.REC-xmlbase-20010627]. When xml:base is used, it serves the function described in section 5.1.1 of URI Generic Syntax [RFC3986], establishing the base URI (or IRI) for resolving any relative references found within the effective scope of the xml:base attribute. @@ -365,66 +372,63 @@ 6.4 RELAX NG Schema Some sections of this specification are illustrated with fragments of a non-normative RELAX NG Compact schema [RNC]. A complete schema appears in Appendix B. However, the text of this specification provides the definition of conformance. 7. Introspection Documents For authoring to commence, a client needs to first discover the - capabilities and locations of collections offered. This is done - using Introspection Documents. An Introspection Document describes - workspaces, which are server-defined groupings of collections. + capabilities and locations of the available collections. + Introspection documents are designed to support this discovery + process. An Introspection Document describes workspaces, which are + server-defined groupings of collections. Introspection documents are identified with the "application/ - atomserv+xml" media type (see Section 15). + atomserv+xml" media type (see Section 14). While an introspection document allows multiple workspaces, there is - no requirement that a service support multiple workspaces. In + no requirement that a server support multiple workspaces. In addition, a collection MAY appear in more than one workspace. 7.1 Example - entry - + href="http://example.org/reilly/main" /> - media + image/* - entry - + href="http://example.org/reilly/list" /> This Introspection Document describes two workspaces. The first, called "Main Site", has two collections called "My Blog Entries" and - "Pictures" whose URIs are "http://example.org/reilly/main" and - "http://example.org/reilly/pic" respectively. "My Blog Entries" is - an Entry collection and "Pictures" is a Media collection. Entry and - Media collections are discussed in Section 7.2.4. + "Pictures" whose IRIs are "http://example.org/reilly/main" and + "http://example.org/reilly/pic" respectively. The "Pictures" + includes an accept element indicating that client can post image + files to the collection to create new entries. Entries with + associated media resources are discussed in section 8.3. The second workspace is called "Side Bar Blog" and has a single - collection called "Remaindered Links" whose collection URI is - "http://example.org/reilly/list". "Remaindered Links" is an Entry - collection. + collection called "Remaindered Links" whose collection IRI is + "http://example.org/reilly/list". 7.2 Element Definitions 7.2.1 The "app:service" Element The root of an introspection document is the "app:service" element. The "app:service" element is the container for introspection information associated with one or more workspaces. An app:service element MUST contain one or more app:workspace elements. @@ -436,242 +440,361 @@ element app:service { appCommonAttributes, ( appWorkspace+ & extensionElement* ) } 7.2.2 The "app:workspace" Element The "app:workspace" element contains information elements about the collections of resources available for editing. The app:workspace - element MUST contain one or more app:collection elements. + element MAY contain zero or more app:collection elements. appWorkspace = element app:workspace { appCommonAttributes, attribute title { text }, ( appCollection+ & extensionElement* ) } - In an app:workspace element, the first app:collection element of each - type MUST refer to the preferred or primary collection. In the - following example, the "Entries" collection would be considered the - preferred (or primary) entries collection of the workspace and the - "Photos" collection would be considered the primary media collection: + In an app:workspace element, the first app:collection element MUST + refer to the preferred or primary collection. In the following + example, the "Entries" collection would be considered the preferred + collection: - + - entry - + href="http://example.org/myblog/entries" /> - media + image/* 7.2.2.1 The "title" Attribute The app:workspace element MUST contain a "title" attribute, which gives a human-readable name for the workspace. This attribute is Language-Sensitive. 7.2.3 The "app:collection" Element The "app:collection" describes an Atom Protocol collection. One - child element is defined here for app:collection: "app:member-type". + child element is defined here for app:collection: "app:accept". appCollection = element app:collection { appCommonAttributes, attribute title { text }, - attribute href { text }, - ( appMemberType - & appListTemplate + attribute href { atomUri }, + ( appAccept? & extensionElement* ) } + In an Atom feed, the app:collection element MAY appear as a child of + an atom:feed or atom:source element to identify the collection to + which new entries can be added to the feed. + 7.2.3.1 The "title" Attribute The app:collection element MUST contain a "title" attribute, whose value gives a human-readable name for the collection. This attribute is Language-Sensitive. 7.2.3.2 The "href" Attribute The app:collection element MUST contain a "href" attribute, whose value gives the IRI of the collection. -7.2.4 The "app:member-type" Element +7.2.4 The "app:accept" Element - The app:collection element MUST contain one "app:member-type" - element. The app:member-type element value specifies the types of - members that can appear in the collection. + The app:collection element MAY contain one "app:accept" element. The + app:accept element value specifies a comma-separated list of media- + ranges [RFC2616] identifying the types of representations that can be + POSTed to the Collection's URI. Whitespace separating the media- + range values is considered insignificant and MUST be ignored. - appMemberType = - element app:member-type { - appCommonAttributes, - ( appTypeValue ) - } + The app:accept element is similar to the HTTP Accept request-header + [RFC2616] with the exception that app:accept has no notion of + preference. Accordingly, the value syntax of app:accept does not use + accept-params or "q" parameters as specified in [RFC2616], section + 14.1. The order of media-ranges is not significant. The following + lists are all equivalent: - appTypeValue = "entry" | "media" + image/png, image/* + image/*, image/png + image/* - This specification defines two values for the app:member-type - element: + A value of "entry" indicates that Atom Entry Documents can be posted + to the Collection. If the accept element is omitted, or empty, + clients SHOULD assume that only Atom Entry documents will be accepted + by the collection. - o "entry" - Indicates the collection contains only member resources - whose representation MUST be an Atom Entry. Further constraints - on the representations of members in a collection of type "entry" - are listed in Section 8.2. + appAccept = + element app:accept { + appCommonAttributes, + ( appTypeValue? ) + } - o "media" - Indicates the collection contains member resources whose - representation can be of any media type. Additional constraints - are listed in Section 8.3. + appTypeValue = ( "entry" | media-type |entry-or-media-type ) + media-type = xsd:string { pattern = "entry,(.+/.+,?)*" } + entry-or-media-type = xsd:string { pattern = "(.+/.+,?)*" } 8. Collections 8.1 Creating resources with POST To add members to a collection, clients send POST requests to the collection's URI. Collections MAY impose constraints on the media- - types that are created in a collection and MAY generate a response - with a status code of 415 ("Unsupported Media Type"). On successful - creation, the response to the POST request MUST return a Location: - header with the URI of the newly created resource. + types of request entities POSTed to the collection and MAY generate a + response with a status code of 415 ("Unsupported Media Type"). -8.1.1 Example + If an entry was created in the collection which received the POST, + its 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. Clients MUST NOT assume that an Atom Entry + returned is a full representation of the member resource. + + Since the server is free to alter the posted entry, for example by + changing the content of the "id" element. returning the entry as + described in the previous paragraph can be useful to the client, + enabling it to correlate the client and server views of the new + entry. + + When the POST request contains an Atom Entry Document, the response + from the server SHOULD contain a Content-Location header that + contains the same character-by-character value as the Location + header. + + Clients MUST NOT assume that the URI provided by the Location header + can be used to edit the created entry. + + The request body of the POST need not be an Atom entry. For example, + it might be a picture, or a movie. For a discussion of the issues in + posting such content, see Section 8.4. + +8.2 Example Below, the client sends a POST request containing an Atom Entry representation to the URI of the Collection: POST /myblog/entries HTTP/1.1 Host: example.org User-Agent: Thingio/1.0 Content-Type: application/atom+xml Content-Length: nnn + Atom-Powered Robots Run Amok urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a 2003-12-13T18:30:02Z + John Doe Some text. - The server signals a successful creation with a status code of 201 - and the response includes a 'Location' header indicating the URI of - the Atom Entry. + The server signals a successful creation with a status code of 201. + The response includes a "Location" header indicating the URI of the + Atom Entry and a representation of that Entry in the body of the + response. HTTP/1.1 201 Created Date: Fri, 7 Oct 2005 17:17:11 GMT - Content-Length: 0 + Content- Length: nnn + Content- Type: application/atom+xml; charset="utf-8" + Content- Location: http://example.org/edit/first-post.atom Location: http://example.org/edit/first-post.atom -8.1.2 Title: Header + + + Atom-Powered Robots Run Amok + urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a + 2003-12-13T18:30:02Z + John Doe + Some text. + + - A POST to a Media Collection creating a resource SHOULD contain a - Title: header that indicates the client's suggested title for the - resource: + Note that the Entry created by the server might not match exactly the + Entry POSTed by the client. In particular, a server MAY change the + values of various elements in the Entry such as the atom:id, atom: + updated and atom:author values and MAY choose to remove or add other + elements and attributes, or change element and attribute values. + + In particular, the publishing system in this example filled in some + values not provided in the original POST. For example, presumably it + ascertained the author's name via the authentication protocol used to + establish the right to post. + +8.3 The 'edit' Link + + Each member Entry within a collection SHOULD contain an atom:link + element with a link relation of "edit" that contains the IRI used to + retrieve, update or delete the member Entry. + +8.4 Media Resources and Media Link Entries + + As discussed above, if the body of a client's POST is an Atom Entry + document, this constitutes a request that the server create a new + entry in the collection to which the POST is addressed and return its + URI. + + If the body of the client's POST is of a media type other than + application/atom+xml, this constitutes a request that the server + create a new resource as represented by the body of the post, called + a "media resource", and also an entry in the collection to which the + POST was addressed, called a "media link entry", and return both + URIs. If the server successfully creates a media resource and media + link entry pair, the Location header included in the response MUST be + that of the media link entry. The media link entry MUST have a + "content" element with a "src" attribute which links to the media + resource. + + The intent is that the media link entry be used to store metadata + about the (perhaps non-textual) media resource, so that the media and + the metadata can be retrieved and updated separately. + + A media link entry SHOULD contain an atom:link element with a link + relation of "edit-media" that contains the IRI used to modify the + media resource. Deletion of a media link entry SHOULD result in the + deletion of the linked media resource. + + Implementors will note that per the requirements of [RFC4287], media + link entries MUST contain an atom:summary element. Upon successful + creation of a media link entry, a server MAY choose to populate the + atom:summary element (as well as other required elements such as + atom:id, atom:author and atom:title) with content derived from the + POSTed media resource or from any other source. A server might not + allow a client to modify the server selected values for these + elements. + + Note that this specification covers the cases when the POST body is + an Atom Entry, and when it is of a non-Atom media type. It does not + specify any request semantics or server behavior in the case where + the POST media-type is application/atom+xml but the body is something + other than an Atom Entry. + +8.4.1 Title: Header + + A POST whose body is not of the Atom media type and which thus + requests the creation of a media resource SHOULD contain a Title: + header indicating the client's suggested title for the resource. For + example: POST /myblog/fotes HTTP/1.1 Host: example.org - User-Agent: Thingio/1.0 Content-Type: image/png Content-Length: nnnn Title: An Atom-Powered Robot ...binary data... - The server MAY ignore the content of the Title: header or modify the - suggested title. + The server MAY use the content of the Title: header, as provided or + in a modified form, in constructing a title for the resource, which + would presumably appear in the media link entry. Title = "Title" ":" [TEXT] 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] rule is described in section 2.2 of the same document. Words of *TEXT MAY contain characters from character sets other than - [ISO88591] only when encoded according to the rules of - [RFC2047]. - -8.2 Entry Collections + [ISO88591] only when encoded according to the rules of [RFC2047]. - Entry Collections are collections that restrict their membership to - Atom Entries. They are identified by having an app:member-type of - "entry". Every member representation MAY contain an atom:link - element with a link relation of "edit" that contains the IRI of the - member resource. Member representations MAY contain a pub:control - element (Section 11). +8.4.2 Example -8.2.1 Editing entries with foreign markup + Below, the client sends a POST request containing a PNG image to the + URI of the Collection: - To avoid unintentional loss of data when editing entry collection - members, Atom Protocol clients SHOULD preserve all metadata, - including unknown foreign markup, that has not been intentionally - modified. + POST /myblog/entries HTTP/1.1 + Host: example.org + Content- Type: image/png + Content- Length: nnn + Title: A picture of the beach -8.3 Media Collections + ...binary data... - Media Collections are collections whose member representations are - not constrained. They are identified by having an app:member-type of - "media". + The server signals a successful creation with a status code of 201. + The response includes a "Location" header indicating the URI of the + media link entry and a representation of that entry in the body of + the response. The media link entry includes a content element with a + src attribute referencing the media resource, and a link using the + link relation "edit-media" specifying the IRI to be used for + modifying the media resource. -8.3.1 Editing Media Resources + HTTP/1.1 201 Created + Date: Fri, 7 Oct 2005 17:17:11 GMT + Content- Length: nnn + Content- Type: application/atom+xml; charset="utf-8" + Content- Location: http://example.org/edit/first-post.atom + Location: http://example.org/edit/first-post.atom - When listing the contents of a Media Collection, every Entry in the - Atom Feed Document MUST have an atom:content element with a "src" - attribute containing the IRI of the media resource itself. This - value may be used to update and delete resources as described in - Section 5.3. When creating a public, read-only reference to the - member resource, a client SHOULD use this value. + + + A picture of the beach + urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a + 2003-12-13T18:30:02Z + John Doe + + + + + -8.3.2 Editing Media Metadata +8.5 Editing Entries with Foreign Markup - Entries in a Media Collection MAY contain an atom:link element with a - link relation of "edit" that contains the IRI of an Atom Entry - document representing the metadata of the member resource. A client - MAY use this to edit the metadata associated with the resource. + To avoid unintentional loss of data when editing entries or media + link entries, Atom Protocol clients SHOULD preserve all metadata, + including unknown foreign markup as defined in Section 6 of + [RFC4287], which has not been intentionally modified. 9. Listing Collections Collection resources MUST provide representations in the form of Atom - Feed documents. Each entry in the Feed Document MUST have an atom: - link element with a relation of "edit" (See Section 10.1). + Feed documents whose entries represent the collection's members. + Each entry in the Feed Document SHOULD have an atom:link element with + a relation of "edit" (See Section 10.1). The entries in the returned Atom Feed MUST be ordered by their "atom: updated" property, with the most recently updated entries coming first in the document order. Clients SHOULD be constructed in - consideration that changes which do not alter the entry's + consideration of the fact that changes which do not alter the entry's atom:updated value will not affect the position of the entry in a collection. Clients MUST NOT assume that an Atom Entry returned in the Feed is a full representation of a member resource and SHOULD perform a GET on the member resource before editing. Collections can contain large numbers of resources. A naive client such as a web spider or web browser could be overwhelmed if the response to a GET contained every entry in the collection, and the server would waste large amounts of bandwidth and processing time on clients unable to handle the response. For this reason, servers MAY return a partial listing containing the most recently updated member resources. Such partial feed documents MUST have an atom:link with a "next" relation whose "href" value is the URI of the next partial listing of the collection (the least recently updated member resources) where it exists. This is called "collection paging". 9.1 Collection Paging - Atom Protocol servers MUST provide representations of collections as - Atom feed documents whose entries represent the collection's members. The returned Atom feed MAY NOT contain entries for all the collection's members. Instead, the Atom feed document MAY contain link elements with "rel" attribute values of "next", "previous", "first" and "last" that can be used to navigate through the complete set of matching entries. For instance, suppose a client is supplied the URI "http://example.org/entries/go" of a collection of member entries, where the server as a matter of policy avoids generating feed documents containing more than 10 entries. The Atom feed document @@ -706,27 +829,44 @@ href="http://example.org/entries/10" /> ... 10. Atom Format Link Relation Extensions 10.1 The "edit" Link Relation The Atom Protocol adds the value "edit" to the Atom Registry of Link Relations (see section 7.1 of [RFC4287]). The value of "edit" - specifies that the IRI in the value of the href attribute is the IRI - of an editable Atom Entry Document associated with a resource. In a - Media Collection this IRI may be used to update the metadata - associated with a Media Resource. In an Entry Collection this IRI - may be used to update and delete the member resource itself. The - link relation MAY appear in Atom Entry representations as well as - Entry and Media Collections. + specifies that the value of the href attribute is the IRI of an + editable Atom Entry Document. When appearing within an atom:entry, + the href IRI MAY be used to update and delete the resource + represented by that entry. An atom:entry MUST contain no more than + one "edit" link relation. + +10.2 The "edit-media" Link Relation + + The Atom Protocol adds the value "edit-media" to the Atom Registry of + Link Relations (see section 7.1 of [RFC4287]). When appearing within + an atom:entry, the value of the href attribute is an IRI that MAY be + used to modify a media resource associated with that entry. + + An atom:entry MAY contain zero or more "edit-media" link relations. + An atom:entry MUST NOT contain more than one atom:link element with a + rel attribute value of "edit-media" that has the same type and + hreflang attribute values. All "edit-media" link relations in the + same entry reference the same resource. If a client encounters + multiple "edit-media" link relations in an entry then it SHOULD + choose a link based on the client preferences for type and hreflang. + If a client encounters multiple "edit-media" link relations in an + entry and has no preference based on the type and hreflang attributes + then the client SHOULD pick the first "edit-media" link relation in + document order. 11. Atom Publishing Control Extensions 11.1 The Atom Publishing Control Namespace This specification defines an Atom Format extension for publishing control called Atom Publishing Control. The namespace name for the Atom Publishing Control's XML vocabulary is "http://example.net/appns/". This specification uses "pub:" for the namespace prefix. The choice of namespace prefix is not semantically @@ -759,186 +899,69 @@ as defined here, and MAY contain zero or more extension elements as outlined in Section 6 of [RFC4287]. Both clients and servers MUST ignore foreign markup present in the pub:control element. 11.2.1 The "pub:draft" Element The number of "pub:draft" elements in "pub:control" MUST be zero or one. Its value MUST be one of "yes" or "no". A value of "no" means that the entry MAY be made publicly visible. If the "pub:draft" element is missing then the value MUST be understood to be "no". The - pub:draft element MAY be ignored. - -12. Atom Publishing Protocol Example - - This is an example of a client creating a new entry with an image. - The client has an image to publish and an entry that includes an HTML - "img" element that uses that image. In this scenario we consider a - client that has IRIs of two collections, an entry collection and a - media collection, both of which were discovered through an - introspection document. The IRI of the entry collection is: - - http://example.net/blog/edit/ - - The IRI of the media collection is: - - http://example.net/binary/edit - - First the client creates a new image resource by POSTing the image to - the IRI of the media collection. - - POST /binary/edit/ HTTP/1.1 - Host: example.net - User-Agent: Thingio/1.0 - Content-Type: image/png - Content-Length: nnnn - Title: A picture of the beach - - ...binary data... - - The member resource is created and an HTTP status code of 201 is - returned. - - HTTP/1.1 201 Created - Date: Fri, 25 Mar 2005 17:17:11 GMT - Content-Length: nnnn - Content-Type: application/atom+xml - Location: http://example.net/binary/edit/b/129.png - - - - A picture of the beach - - urn:uuid:1225c695-cfb8-4ebb-aaaa-568596895695 - 2005-09-02T10:30:00Z - Waves - - - The client then POSTs the Atom Entry that refers to the newly created - image resource. Note that the client takes the URI - http://example.net/binary/readonly/129.png and uses it in the 'img' - element in the Entry content: - - POST /blog/edit/ HTTP/1.1 - Host: example.net - User-Agent: Thingio/1.0 - Content-Type: application/atom+xml - Content-Length: nnnn - - - - What I did on my summer vacation - - urn:uuid:1225c695-ffb8-4ebb-aaaa-80da354efa6a - 2005-09-02T10:30:00Z - Beach! - -
-

We went to the beach for summer vacation. - Here is a picture of the waves rolling in: - A picture of the beach -

-
- - + inclusion of the pub:draft element represents a request by the client + to control the visibility of an entry and the pub:draft element MAY + be ignored by the server. -13. Securing the Atom Protocol +12. Securing the Atom Protocol All instances of publishing Atom Format entries SHOULD be protected by authentication to prevent posting or editing by unknown sources. - Atom Protocol servers and clients MUST support one of the following - authentication mechanisms, and SHOULD support both. - - o HTTP Digest Authentication [RFC2617] - - o CGI Authentication - - Atom Protocol servers and clients MAY support encryption of the - session using TLS (see [RFC2246]). - - There are cases where an authentication mechanism might not be - required, such as a publicly editable Wiki, or when using POST to - send comments to a site that does not require authentication from a - commenter. - -13.1 CGI Authentication - - [[anchor27: note: this section is incomplete; cgi-authentication is - described but is unspecified.]] This authentication method is - included as part of the protocol to allow Atom Protocol servers and - clients that cannot use HTTP Digest Authentication but where the user - can both insert its own HTTP headers and create a CGI program to - authenticate entries to the server. This scenario is common in - environments where the user cannot control what services the server - employs, but the user can write their own HTTP services. - -14. Security Considerations - - The security of the Atom Protocol is based on HTTP Digest - Authentication and/or CGI Authentication [[anchor29: note: refers to - incomplete section]]. Any weaknesses in either of these - authentication schemes will affect the security of the Atom - Publishing Protocol. - - Both HTTP Digest Authentication and CGI Authentication [[anchor30: - note: refers to incomplete section]] are susceptible to dictionary- - based attacks on the shared secret. If the shared secret is a - password (instead of a random string with sufficient entropy), an - attacker can determine the secret by exhaustively comparing the - authenticating string with hashed results of the public string and - dictionary entries. + [[anchor22: note: this section is currently under discussion.]] - See [RFC2617] for the description of the security properties of HTTP - Digest Authentication. +13. Security Considerations - [[anchor31: expand on HTTP basic and digest authentication, or - refer.]] + The security of the Atom Protocol is based on [[anchor24: note: + refers to incomplete section]]. - [[anchor32: note: talk here about denial of service attacks using + [[anchor25: note: talk here about denial of service attacks using large XML files, or the billion laughs DTD attack.]] -15. IANA Considerations +14. IANA Considerations An Atom Publishing Protocol Introspection Document, when serialized as XML 1.0, can be identified with the following media type: MIME media type name: application MIME subtype name: atomserv+xml Mandatory parameters: None. Optional parameters: "charset": This parameter has identical semantics to the charset parameter of the "application/xml" media type as specified in [RFC3023]. Encoding considerations: Identical to those of "application/xml" as described in [RFC3023], section 3.2. Security considerations: As defined in this specification. - [[anchor33: update upon publication]] + [[anchor26: update upon publication]] In addition, as this media type uses the "+xml" convention, it shares the same security considerations as described in [RFC3023], section 10. Interoperability considerations: There are no known interoperability issues. - Published specification: This specification. [[anchor34: update upon + Published specification: This specification. [[anchor27: update upon publication]] Applications that use this media type: No known applications currently use this media type. Additional information: Magic number(s): As specified for "application/xml" in [RFC3023], section 3.2. @@ -949,51 +972,43 @@ Base URI: As specified in [RFC3023], section 6. Macintosh File Type code: TEXT Person and email address to contact for further information: Joe Gregorio Intended usage: COMMON - Author/Change controller: This specification's author(s). [[anchor35: + Author/Change controller: This specification's author(s). [[anchor28: update upon publication]] -16. References +15. References -16.1 Normative References +15.1 Normative References [ISO88591] ISO, "International Standard -- Information Processing -- 8-bit Single-Byte Coded Graphic Character Sets -- Part 1: Latin alphabet No. 1,", January 1987. [RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text", RFC 2047, November 1996. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. - [RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", - RFC 2246, January 1999. - [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. - [RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., - Leach, P., Luotonen, A., and L. Stewart, "HTTP - Authentication: Basic and Digest Access Authentication", - RFC 2617, June 1999. - [RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media Types", RFC 3023, January 2001. [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [RFC3987] Duerst, M. and M. Suignard, "Internationalized Resource Identifiers (IRIs)", RFC 3987, January 2005. @@ -1011,21 +1026,21 @@ February 2004. [W3C.REC-xml-names-19990114] Hollander, D., Bray, T., and A. Layman, "Namespaces in XML", W3C REC REC-xml-names-19990114, January 1999. [W3C.REC-xmlbase-20010627] Marsh, J., "XML Base", W3C REC W3C.REC-xmlbase-20010627, June 2001. -16.2 Informative References +15.2 Informative References [RNC] Clark, J., "RELAX NG Compact Syntax", December 2001. [W3C.REC-webarch-20041215] Walsh, N. and I. Jacobs, "Architecture of the World Wide Web, Volume One", W3C REC REC-webarch-20041215, December 2004. URIs @@ -1111,33 +1126,36 @@ & extensionElement* ) } # app:collection appCollection = element app:collection { appCommonAttributes, attribute title { text }, attribute href { atomUri }, - ( appMemberType + ( appAccept? & extensionElement* ) } # app:member - appMemberType = - element app:member-type { + appAccept = + element app:accept { appCommonAttributes, - ( appTypeValue ) + ( appTypeValue? ) } - appTypeValue = "entry" | "media" + appTypeValue = ( "entry" | media-type |entry-or-media-type ) + media-type = xsd:string { pattern = "entry,(.+/.+,?)*" } + entry-or-media-type = xsd:string { pattern = "(.+/.+,?)*" } + # above is an approximation, rnc doesn't support interleaved text # Simple Extension simpleExtensionElement = element * - app:* { text } # Structured Extension @@ -1160,20 +1177,25 @@ element * { (attribute * { text } | text | anyElement)* } # EOF Appendix C. Revision History + draft-ietf-atompub-protocol-09: PaceWorkspaceMayHaveCollections, + PaceMediaEntries5, + http://www.imc.org/atom-protocol/mail-archive/msg05322.html, and + http://www.imc.org/atom-protocol/mail-archive/msg05272.html + draft-ietf-atompub-protocol-08: added infoset ref; added wording re IRI/URI; fixed URI/IRI ; next/previous fixed as per Atom LinkRelations Attribute (http://www.imc.org/atom-protocol/mail-archive/msg04095.html); incorporated: PaceEditLinkMustToMay; PaceMissingDraftHasNoMeaning, PaceRemoveMemberTypeMust, PaceRemoveMemberTypePostMust, PaceTitleHeaderOnlyInMediaCollections, PacePreserveForeignMarkup, PaceClarifyTitleHeader, PaceClarifyMediaResourceLinks, PaceTwoPrimaryCollections;