Network Working Group J. Snell Internet-Draft August 21, 2007 Intended status: Standards Track Expires: February 22, 2008 Atom Publishing Protocol Features Extension draft-snell-atompub-feature-07.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 other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months 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 February 22, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document introduces extensions to the Atom Publishing Protocol service document format for expressing metadata about the behaviors, functions and capabilities supported by an Atom Publishing Protocol collection. Snell Expires February 22, 2008 [Page 1] Internet-Draft Atompub Features August 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3 3. The f:feature element . . . . . . . . . . . . . . . . . . . . 4 3.1. Example . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.2. Contradictory Features . . . . . . . . . . . . . . . . . . 6 4. The f:type element . . . . . . . . . . . . . . . . . . . . . . 7 4.1. An example f:feature using the f:type element . . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 6.1. Registry of Atom Publishing Features . . . . . . . . . . . 8 6.1.1. Initial Assignments . . . . . . . . . . . . . . . . . 8 7. Normative References . . . . . . . . . . . . . . . . . . . . . 20 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 21 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 21 Intellectual Property and Copyright Statements . . . . . . . . . . 22 Snell Expires February 22, 2008 [Page 2] Internet-Draft Atompub Features August 2007 1. Introduction This document introduces extensions for the Atom Publishing Protocol service document format for expressing metadata about the behaviors, functions and capabilities supported by an Atom Publishing Protocol collection. 2. Notational Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, [RFC2119]. This specification uses XML Namespaces [W3C.REC-xml-names-19990114] to uniquely identify XML element names. It uses the following namespace prefix for the indicated namespace URI; "f": "http://purl.org/atompub/features/1.0" This specification uses terms from the XML Infoset [W3C.REC-xml-infoset-20040204]. However, this specification uses a shorthand; the phrase "Information Item" is omitted when naming Element Information Items. Therefore, when this specification uses the terms "element" and "attribute" it is referring, respectively, to the Element and Attribute Information Items in Infoset terms. This specification uses the terms "atomUri" and "atomCommonAttributes" from the non-normative RELAX NG Compact schema included in [RFC4287]. Where used, these serve the same purpose and have the same meaning as their use in [RFC4287]. Atom allows the use of IRIs [RFC3987]. Every URI [RFC3986] is also an IRI, so a URI may be used wherever below an IRI is named. There are two special considerations: (1) when an IRI that is not also a URI is given for dereferencing, it MUST be mapped to a URI using the steps in Section 3.1 of [RFC3987] and (2) when an IRI is serving as an identifier, it MUST NOT be so mapped. Any element 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 [RFC3986], establishing the base URI (or IRI) for resolving any relative references found within the effective scope of the xml:base attribute. Any element defined by this specification MAY have an xml:lang attribute, whose content indicates the natural language for the Snell Expires February 22, 2008 [Page 3] Internet-Draft Atompub Features August 2007 element and its descendents. The language context is only significant for elements and attributes declared to be "Language- Sensitive". Requirements regarding the content and interpretation of xml:lang are specified in XML 1.0 [W3C.REC-xml-20040204], Section 2.12. 3. The f:feature element A feature is an abstract behavior, function and capability supported by an Atom Publishing Protocol collection. Examples of features that might be supported by an Atom publishing server include support for draft entries, scheduled publication of entries, use of a particular set of Atom format extensions, use of a particular authentication scheme, and so on. The f:feature element can be used in an app: collection element to indicate that the collection supports the feature specified and may require that a client wishing to use the endpoint use that feature. Features are identified using permanent, universally unique IRI's. namespace f = "http://purl.org/atompub/features/1.0" feature = element f:feature { atomCommonAttributes, attribute ref { atomUri }, attribute status { 'supported' | 'required' | 'unsupported'}?, attribute href { atomUri }?, attribute label { text }?, (anyElement)* } anyElement = element * - f:* { (attribute * { text } | text | anyElement)* } The ref attribute specifies a globally unique IRI identifying a feature supported by a collection. The value of the ref attribute MUST be compared on a case-sensitive, character-by-character basis. Relative references MUST NOT be used. The status attribute indicates a collections level of support for the identified feature. The value of the attribute can be "supported", "required" or "unsupported". If not specified, the value is assumed to be "supported". Snell Expires February 22, 2008 [Page 4] Internet-Draft Atompub Features August 2007 o The value "supported" indicates that the server supports the identified feature. Clients MAY utilize the feature when interacting with the collection. o The value "required" indicates that server supports the identified feature. Clients MUST utilize the feature when interacting with the collection. o The value "unsupported" indicates that the server explicitly does not support a feature. Clients SHOULD NOT utilize the feature when interacting with the collection. An optional href attribute MAY be used to specify the URI of a human- readable description of the feature. Relative references MAY be used. The optional label attribute MAY be used to specify a human-readable label for the feature. The value of the label attribute is Language- Sensitive as defined by Section 2 of [RFC4287]. The f:feature element MAY contain child elements and attributes other than those defined in this specification. Such "foreign markup" are considered to be metadata applicable to the feature identified by the f:feature element. Software agents MUST NOT stop processing or signal an error or change their behavior as a result of encountering such foreign markup. An app:collection element MAY contain zero or more f:feature elements but MUST NOT contain more than one with the same ref attribute value. The order in which f:feature elements appear within the app: collection element is insignificant. The f:feature element MAY contain attributes included as part of the atomCommonAttributes production defined by Section 2 of [RFC4287] or any update thereof. When used on an f:feature element, such attributes serve the same purpose described in [RFC4287] or their corresponding specifications. Snell Expires February 22, 2008 [Page 5] Internet-Draft Atompub Features August 2007 3.1. Example The following is an example of a collection supporting one hypothetical required feature, one unsupported feature, and a number of supported features. My Workspace My Atom Collection application/atom+xml;type=entry 3.2. Contradictory Features Some combinations of features can be contradictory when the support level of one or more of those features is "required" and the others are "supported". For instance, a collection that specifies that XHTML values in the atom:title is required and that HTML in an atom: title is supported is contradictory. Such contradictions can cause problems for clients that are attempting to select an appropriate collection based on the support level of various features. A service document MUST NOT specify contradictory features. If a client determines that the features specified in a service document are contradictory, the client SHOULD proceed as if the support level for each of those features is "supported". Snell Expires February 22, 2008 [Page 6] Internet-Draft Atompub Features August 2007 4. The f:type element The content of an f:type element is a media-range as defined in [RFC2616]. The media range specifies a type of content that can be included in an atom:content element or referenced by the atom:content src attribute. type = element f:type { atomCommonAttributes, ( text? ) } Media type parameters are allowed within f:type, but f:type has no notion of preference - "accept-params" or "q" arguments, as specified in Section 14.1 of [RFC2616] are not significant. White space (as defined in [W3C.REC-xml-20040204]) around the f:type element's media-range is insignificant and MUST be ignored. Any number of f:type elements MAY appear as children of an f:feature element. When used with features whose ref attributes identify the "XML Content", "Binary Content" or "Reference Content" features as defined in Section 6.1.1, the f:type elements specify the set of media types that can be specified in the atom:content elements type attribute. If no f:type element are present, clients SHOULD treat this as equivalent to an f:type element with the content "*/*". The order of f:type elements within a f:feature element is insignificant. 4.1. An example f:feature using the f:type element image/jpg image/png image/gif text/* 5. Security Considerations Specific features supported by a collection may introduce security considerations and concerns beyond those discussed by the Atom Snell Expires February 22, 2008 [Page 7] Internet-Draft Atompub Features August 2007 Publishing Protocol and Atom Syndication Format specifications. Implementors must refer to the specifications and description of each feature to determine the security considerations relevant to each. 6. IANA Considerations 6.1. Registry of Atom Publishing Features The Registry of Atom Publishing Features is maintained by IANA and contains information about known features that can be supported by Atom Publishing Protocol implementations. New assignments are subject to IESG approval, as outlined in [RFC2434]. Requests should be made by email to IANA, which will then forward the request to the IESG, requesting approval. The request should use the following template: o Ref: (A globally unique IRI identifying the feature) o Label: (A human-readable label for the feature) o Description: (A human-readable description of the feature) o Support Levels: (A description of the relevant support levels for the feature) o Contradictory Features: (A listing of features that are contradictory to this feature when one or more are marked as "required") o Href: (A URI referencing a document containing a detailed definition of the feature) o Security Considerations: 6.1.1. Initial Assignments The Registry of Features initially contains the following assignments: 6.1.1.1. Drafts o Ref: http://www.w3.org/2007/app/drafts o Label: Drafts o Support Levels: * "supported" indicates that the collection accepts entries that contain the app:draft control element. * "required" indicates that the collection requires all entries to contain the app:draft control element. * "unsupported" indicates that the collection does not accept entries that use the app:draft control element or that the server will ignore the element if present. Snell Expires February 22, 2008 [Page 8] Internet-Draft Atompub Features August 2007 o Contradictory Features: none o Description: The "Drafts" feature indicates that a collection supports the use of the app:draft control element as defined in section 13.1.1 of [I-D.ietf-atompub-protocol]. 6.1.1.2. XHTML Content o Ref: http://www.w3.org/2007/app/xhtml-content o Label: XHTML Content o Support Levels: * "supported" indicates that the collection accepts entries that provide XHTML in the atom:content element. * "required" indicates that the collection requires all entries to provide XHTML in the atom:content element. * "unsupported" indicates that the collection does not accept entries that provide XHTML in the atom:content element. o Contradictory Features: http://www.w3.org/2007/app/html-content, http://www.w3.org/2007/app/text-content, http://www.w3.org/2007/app/xml-content, http://www.w3.org/2007/app/binary-content, http://www.w3.org/2007/app/ref-content o Description: The "XHTML Content" feature indicates that a server will accept the use of an XHTML value within the atom:content element. 6.1.1.3. HTML Content o Ref: http://www.w3.org/2007/app/html-content o Label: HTML Content o Support Levels: * "supported" indicates that the collection accepts entries that provide HTML in the atom:content element. * "required" indicates that the collection requires all entries to provide HTML in the atom:content element. * "unsupported" indicates that the collection does not accept entries that provide HTML in the atom:content element. o Contradictory Features: http://www.w3.org/2007/app/xhtml-content, http://www.w3.org/2007/app/text-content, http://www.w3.org/2007/app/xml-content, http://www.w3.org/2007/app/binary-content, http://www.w3.org/2007/app/ref-content o Description: The "HTML Content" feature indicates that a server will accept the use of an escaped HTML value within the atom: content element. Snell Expires February 22, 2008 [Page 9] Internet-Draft Atompub Features August 2007 6.1.1.4. Text Content o Ref: http://www.w3.org/2007/app/text-content o Label: Text Content o Support Levels: * "supported" indicates that the collection accepts entries that provide plain text in the atom:content element. * "required" indicates that the collection requires all entries to provide plain text in the atom:content element. * "unsupported" indicates that the collection does not accept entries that provide plain text in the atom:content element. o Contradictory Features: http://www.w3.org/2007/app/xhtml-content, http://www.w3.org/2007/app/html-content, http://www.w3.org/2007/app/xml-content, http://www.w3.org/2007/app/binary-content, http://www.w3.org/2007/app/ref-content o Description: The "Text Content" feature indicates that a server will accept the use of a plain text value within the atom:content element. 6.1.1.5. XML Content o Ref: http://www.w3.org/2007/app/xml-content o Label: XML Content o Support Levels: * "supported" indicates that the collection accepts entries that provide well-formed XML in the atom:content element. * "required" indicates that the collection requires all entries to provide well-formed XML in the atom:content element. * "unsupported" indicates that the collection does not accept entries that provide XML in the atom:content element. The MIME media type of acceptable XML formats is specified using one or more f:type elements within the f:feature. o Contradictory Features: http://www.w3.org/2007/app/xhtml-content, http://www.w3.org/2007/app/html-content, http://www.w3.org/2007/app/text-content, http://www.w3.org/2007/app/binary-content, http://www.w3.org/2007/app/ref-content o Description: The "XML Content" feature indicates that a server will accept the use of well-formed XML content within the atom: content element. 6.1.1.6. Binary Content o Ref: http://www.w3.org/2007/app/binary-content o Label: Binary Content Snell Expires February 22, 2008 [Page 10] Internet-Draft Atompub Features August 2007 o Support Levels: * "supported" indicates that the collection accepts entries that provide binary content in the atom:content element. * "required" indicates that the collection requires all entries to provide binary content in the atom:content element. * "unsupported" indicates that the collection does not accept entries that provide binary content in the atom:content element. The MIME media type of acceptable binary formats is specified using one or more f:type elements within the f:feature. o Contradictory Features: http://www.w3.org/2007/app/xhtml-content, http://www.w3.org/2007/app/html-content, http://www.w3.org/2007/app/text-content, http://www.w3.org/2007/app/xml-content, http://www.w3.org/2007/app/ref-content o Description: The "Binary Content" feature indicates that a server will accept Base-64 encoded binary data within the atom:content element. 6.1.1.7. Referenced Content o Ref: http://www.w3.org/2007/app/ref-content o Label: XHTML Content o Support Levels: * "supported" indicates that the collection accepts entries that use the atom:content src attribute to reference external content. * "required" indicates that the collection requires all entries to use the atom:content src attribute to reference external content. * "unsupported" indicates that the collection does not accept entries that use the atom:content src attribute. The MIME media type of acceptable referenced resources is specified using one or more f:type elements within the f:feature. o Contradictory Features: http://www.w3.org/2007/app/xhtml-content, http://www.w3.org/2007/app/html-content, http://www.w3.org/2007/app/text-content, http://www.w3.org/2007/app/xml-content, http://www.w3.org/2007/app/binary-content o Description: The "Referenced Content" feature indicates that a server will accept atom:content elements that use the src attribute to reference external content resources. 6.1.1.8. XHTML Title o Ref: http://www.w3.org/2007/app/xhtml-title Snell Expires February 22, 2008 [Page 11] Internet-Draft Atompub Features August 2007 o Label: XHTML Title o Support Levels: * "supported" indicates that the collection accepts entries that provide XHTML in the atom:title element. * "required" indicates that the collectionrequires all entries to provide XHTML in the atom:title element. * "unsupported" indicates that the collection does not accept entries that provide XHTML in the atom:title element. o Contradictory Features: http://www.w3.org/2007/app/html-title, http://www.w3.org/2007/app/text-title o Description: The "XHTML Title" feature indicates that a server will accept the use of an XHTML value within the atom:title element. 6.1.1.9. HTML Title o Ref: http://www.w3.org/2007/app/html-title o Label: HTML Title o Support Levels: * "supported" indicates that the collection accepts entries that provide HTML in the atom:title element. * "required" indicates that the collection requires all entries to provide HTML in the atom:title element. * "unsupported" indicates that the collection does not accept entries that provide HTML in the atom:title element. o Contradictory Features: http://www.w3.org/2007/app/xhtml-title, http://www.w3.org/2007/app/text-title o Description: The "HTML Content" feature indicates that a server will accept the use of an escaped HTML value within the atom:title element. 6.1.1.10. Text Title o Ref: http://www.w3.org/2007/app/text-title o Label: Text Title o Support Levels: * "supported" indicates that the collection accepts entries that provide plain text in the atom:title element. * "required" indicates that the collection requires all entries to provide plain text in the atom:title element. * "unsupported" indicates that the collection does not accept entries that provide plain text in the atom:title element. o Contradictory Features: http://www.w3.org/2007/app/xhtml-title, http://www.w3.org/2007/app/html-title o Description: The "Text Content" feature indicates that a server will accept the use of a plain text value within the atom:title element. Snell Expires February 22, 2008 [Page 12] Internet-Draft Atompub Features August 2007 6.1.1.11. XHTML Summary o Ref: http://www.w3.org/2007/app/xhtml-summary o Label: XHTML Summary o Support Levels: * "supported" indicates that the collection accepts entries that provide XHTML in the atom:summary element. * "required" indicates that the collection requires all entries to provide XHTML in the atom:summary element. * "unsupported" indicates that the collection does not accept entries that provide XHTML in the atom:summary element. o Contradictory Features: http://www.w3.org/2007/app/html-summary, http://www.w3.org/2007/app/text-summary o Description: The "XHTML Summary" feature indicates that a server will accept the use of an XHTML value within the atom:summary element. 6.1.1.12. HTML Summary o Ref: http://www.w3.org/2007/app/html-summary o Label: HTML Summary o Support Levels: * "supported" indicates that the collection accepts entries that provide HTML in the atom:summary element. * "required" indicates that the collection requires all entries to provide HTML in the atom:summary element. * "unsupported" indicates that the collection does not accept entries that provide HTML in the atom:summary element. o Contradictory Features: http://www.w3.org/2007/app/xhtml-summary, http://www.w3.org/2007/app/text-summary o Description: The "HTML Summary" feature indicates that a server will accept the use of an escaped HTML value within the atom: summary element. 6.1.1.13. Text Summary o Ref: http://www.w3.org/2007/app/text-summary o Label: Text Summary o Support Levels: * "supported" indicates that the collection accepts entries that provide plain text in the atom:summary element. * "required" indicates that the collection requires all entries to provide plain text in the atom:summary element. * "unsupported" indicates that the collection does not accept entries that provide plain text in the atom:summary element. o Contradictory Features: http://www.w3.org/2007/app/xhtml-summary, http://www.w3.org/2007/app/html-summary Snell Expires February 22, 2008 [Page 13] Internet-Draft Atompub Features August 2007 o Description: The "Text Summary" feature indicates that a server will accept the use of a plain text value within the atom:summary element. 6.1.1.14. Auto Summary o Ref: http://www.w3.org/2007/app/auto-summary o Label: Auto Summary o Support Levels: * "supported" indicates that the server will automatically generate an atom:summary element if the entry provided by the client does not already contain one. * "required" indicates that the server will automatically generate an atom:summary element regardless of whether the entry already contains one. * "unsupported" indicates that the server will not automatically generate an atom:summary element. o Contradictory Features: http://www.w3.org/2007/app/xhtml-summary, http://www.w3.org/2007/app/html-summary, http://www.w3.org/2007/app/text-summary o Description: The "Auto Summary" feature indicates that a server will autogenerate the value of the atom:summary element and will either reject or ignore attempts by the client to modify the value of atom:summary. 6.1.1.15. XHTML Rights o Ref: http://www.w3.org/2007/app/xhtml-rights o Label: XHTML Rights o Support Levels: * "supported" indicates that the collection accepts entries that provide XHTML in the atom:rights element. * "required" indicates that the collection requires all entries to provide XHTML in the atom:rights element. * "unsupported" indicates that the collection does not accept entries that provide XHTML in the atom:rights element. o Contradictory Features: http://www.w3.org/2007/app/html-rights, http://www.w3.org/2007/app/text-rights o Description: The "XHTML Rights" feature indicates that a server will accept the use of an XHTML value within the atom:rights element. 6.1.1.16. HTML Rights o Ref: http://www.w3.org/2007/app/html-rights o Label: HTML Rights Snell Expires February 22, 2008 [Page 14] Internet-Draft Atompub Features August 2007 o Support Levels: * "supported" indicates that the collection accepts entries that provide HTML in the atom:rights element. * "required" indicates that the collection requires all entries to provide HTML in the atom:rights element. * "unsupported" indicates that the collection does not accept entries that provide HTML in the atom:rights element. o Contradictory Features: http://www.w3.org/2007/app/xhtml-rights, http://www.w3.org/2007/app/text-rights o Description: The "HTML Rights" feature indicates that a server will accept the use of an escaped HTML value within the atom: rights element. 6.1.1.17. Text Rights o Ref: http://www.w3.org/2007/app/text-rights o Label: Text Rights o Support Levels: * "supported" indicates that the collection accepts entries that provide plain text in the atom:rights element. * "required" indicates that the collection requires all entries to provide plain text in the atom:rights element. * "unsupported" indicates that the collection does not accept entries that provide plain text in the atom:rights element. o Contradictory Features: http://www.w3.org/2007/app/xhtml-rights, http://www.w3.org/2007/app/html-rights o Description: The "Text Rights" feature indicates that a server will accept the use of a plain text value within the atom:rights element. 6.1.1.18. Authenticated Author o Ref: http://www.w3.org/2007/app/auth-author o Label: Authenticated Author o Support Levels: * "supported" indicates that the server will automatically generate the atom:author element based on the client's authenticated identity. * For this feature,"required" is synonymous with "supported". * "unsupported" indicates that the server will not automatically generate the atom:author for an entry based on the client's authenticated identity. o Contradictory Features: http://www.w3.org/2007/app/multiple-authors o Description: The "Authenticated Author" feature indicates that a server will use the authenticated identity of the client to determine the values to use within the atom:author element. Attempts by a client to manually set or modify the author Snell Expires February 22, 2008 [Page 15] Internet-Draft Atompub Features August 2007 information will either be rejected or ignored by the server. 6.1.1.19. Slug o Ref: http://www.w3.org/2007/app/slug o Label: Slug o Support Levels: * "supported" indicates that the collection accepts the use of the Slug header in POST requests. * "required" indicates that the collection requires that the Slug header be used for all POST requests. * "unsupported" indicates that the collection will not accept the use of the Slug header in POST requests or that the header will be ignored. o Contradictory Features: none o Description: The "Slug" feature indicates that a server will use the Slug request header defined in section 9.7 of [I-D.ietf-atompub-protocol] to set the URI of newly created resources. 6.1.1.20. Multiple Categories o Ref: http://www.w3.org/2007/app/multiple-categories o Label: Multiple Categories o Support Levels: * "supported" indicates that the collection accepts the use of multiple atom:category elements within an entry. * For this feature, "required" is synonymous with "supported". * "unsupported" indicates that the collection will not accept entries with multiple atom:category elements or that that additional atom:category elements will be ignored. o Contradictory Features: none o Description: The "Multiple Categories" feature indicates that a server will accept entries that contain multiple atom:category elements. 6.1.1.21. Multiple Authors o Ref: http://www.w3.org/2007/app/multiple-authors o Label: Multiple Authors o Support Levels: * "supported" indicates that the collection accepts the use of multiple atom:author elements within an entry. * For this feature, "required" is synonymous with "supported". * "unsupported" indicates that the collection will not accept entries with multiple atom:author elements or that the additional atom:author elements will be ignored. Snell Expires February 22, 2008 [Page 16] Internet-Draft Atompub Features August 2007 o Contradictory Features: http://www.w3.org/2007/app/auth-author o Description: The "Multiple Authors" feature indicates that a server will accept and preserve multiple atom:author elements contained by an entry. 6.1.1.22. Multiple Contributors o Ref: http://www.w3.org/2007/app/contributors o Label: Multiple Contributors o Support Levels: * "supported" indicates that the collection accepts the use of multiple atom:contributor elements within an entry. * For this feature, "required" is synonymous with "supported". * "unsupported" indicates that the collection will not accept entries with multiple atom:contributor elements or that the additional atom:contributor elements will be ignored. o Contradictory Features: none o Description: The "Multiple Contributors" feature indicates that a server will accept and preserve atom:contributor elements contained by an entry. 6.1.1.23. Preserve Infoset o Ref: http://www.w3.org/2007/app/preserve-infoset o Label: Preserve Infoset o Support Levels: * "supported" indicates that the collection will store entries in such a way as to preserve the complete XML infoset of the entry document. * For this feature, "required" is synonymous with "supported". * "unsupported" indicates that the collection will not preserve the complete XML infoset of the entry when storing. o Contradictory Features: none o Description: The "Preserve Infoset" feature indicates that a server will preserve the complete XML Infoset [W3C.REC-xml-infoset-20040204] of entries POST or PUT to a collection. 6.1.1.24. Preserve IDs o Ref: http://www.w3.org/2007/app/preserve-id o Label: Preserve IDs o Support Levels: * "supported" indicates that the collection will preserve the value of the atom:id element as provided by the client. * For this feature, "required" is synonymous with "supported". Snell Expires February 22, 2008 [Page 17] Internet-Draft Atompub Features August 2007 * "unsupported" indicates that the collection will not preserve the value of the atom:id element as provided by the client (e.g. the server will generate it's own value for the atom:id element. o Contradictory Features: none o Description: The "Preserve IDs" feature indicates that a server will preserve the value of atom:id elements as provided by a client. 6.1.1.25. Preserve Dates o Ref: http://www.w3.org/2007/app/preserve-updated o Label: Preserve Dates o Support Levels: * "supported" indicates that the collection will preserve the value of all date elements as provided by the client. * For this feature,"required" is synonymous with "supported". * "unsupported" indicates that the collection will not preserve the value of date elements as provided by the client (e.g. the server will generate it's own value for the date elements. o Contradictory Features: none o Description: The "Preserve Dates" feature indicates that a server will preserve the value of the atom:updated and atom:published elements as provided by a client. 6.1.1.26. Preserve Extensions o Ref: http://www.w3.org/2007/app/preserve-extensions o Label: Preserve Extensions o Support Levels: * "supported" indicates that the collection will preserve all extensions contained within an entry. * For this feature, "required" is synonymous with "supported". * "unsupported" indicates that the collection will not preserve all extensions contained within an entry, however some extensions may be preserved. o Contradictory Features: none o Description: The "Preserve Extensions" feature indicates that a server will preserve unknown foreign markup contained within an entry. 6.1.1.27. Preserve Links o Ref: http://www.w3.org/2007/app/preserve-links o Label: Preserve Links o Support Levels: Snell Expires February 22, 2008 [Page 18] Internet-Draft Atompub Features August 2007 * "supported" indicates that the collection will preserve all atom:link elements contained within an entry. * For this feature, "required" is synonymous with "supported". * "unsupported" indicates that the collection will not preserve all atom:links contained within an entry, however some atom: link elements may be preserved. o Contradictory Features: none o Description: The "Preserve Links" feature indicates that a server will preserve all atom:link elements contained within an entry. 6.1.1.28. Preserve Rights o Ref: http://www.w3.org/2007/app/preserve-rights o Label: Preserve Rights o Support Levels: * "supported" indicates that the collection will preserve the value of the atom:rights element as well as all License Links [RFC4946] contained within an entry. * For this feature, "required" is synonymous with "supported". * "unsupported" indicates that the collection may not preserve the value of the atom:rights element or all License Links [RFC4946], however, some rights information may be preserved. o Contradictory Features: none o Description: The "Preserve Rights" feature indicates that a server will preserve all atom:rights elements and License Links [RFC4946] contained within an entry. 6.1.1.29. Threading o Ref: http://purl.org/syndication/thread/1.0 o Label: Threading o Support Levels: * "supported" indicates that the collection accepts entries that contain the in-reply-to element as defined by [RFC4685]. * "required" indicates that the collection requires that all entries contain an in-reply-to element. * "unsupported" indicates that the collection will not accept entries containing the in-reply-to element or that the element will be ignored if present. o Contradictory Features: none o Description: The Feed Thread feature indicates that the collection accepts entries that contain the in-reply-to element as defined by [RFC4685]. 6.1.1.30. Scheduled Publishing Snell Expires February 22, 2008 [Page 19] Internet-Draft Atompub Features August 2007 o Ref: http://www.w3.org/2007/app/scheduled-publishing o Label: Scheduled Publishing o Support Levels: * "supported" indicates that the collection allows clients to specify a future instant in time for the atom:published element when the entry should be made publicly available. * "required" indicates that the collection requires clients to specify a future instant in time for the atom:published element. * "unsupported" indicates that the collection will not allow clients to specify a future instance in time for the atom: published element. o Contradictory Features: none o Description: The "Scheduled Publishing" feature indicates that a collection allows clients to set the value of an entries atom: published element to some future point in time after which the entry will be made publicly visible. Prior to that time, the entry will be considered to be in a draft state and SHOULD contain an app:draft control element with a value of "yes". 7. Normative References [I-D.ietf-atompub-protocol] Hora, B. and J. Gregorio, "The Atom Publishing Protocol", draft-ietf-atompub-protocol-17 (work in progress), July 2007. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [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. [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. [RFC4287] Nottingham, M., Ed. and R. Sayre, Ed., "The Atom Syndication Format", RFC 4287, December 2005. Snell Expires February 22, 2008 [Page 20] Internet-Draft Atompub Features August 2007 [RFC4685] Snell, J., "Atom Threading Extensions", RFC 4685, September 2006. [RFC4946] Snell, J., "Atom License Extension", RFC 4946, July 2007. [W3C.REC-xml-20040204] Maler, E., Sperberg-McQueen, C., Paoli, J., Yergeau, F., and T. Bray, "Extensible Markup Language (XML) 1.0 (Third Edition)", World Wide Web Consortium FirstEdition REC-xml- 20040204, February 2004, . [W3C.REC-xml-infoset-20040204] Tobin, R. and J. Cowan, "XML Information Set (Second Edition)", World Wide Web Consortium Recommendation REC- xml-infoset-20040204, February 2004, . [W3C.REC-xml-names-19990114] Hollander, D., Bray, T., and A. Layman, "Namespaces in XML", World Wide Web Consortium FirstEdition REC-xml- names-19990114, January 1999, . [W3C.REC-xmlbase-20010627] Marsh, J., "XML Base", World Wide Web Consortium Recommendation REC-xmlbase-20010627, June 2001, . Appendix A. Acknowledgements The author acknowledges the feedback from the other members of the IETF Atom Publishing working group during the development of this specification. Author's Address James M Snell Phone: Email: jasnell@gmail.com URI: http://snellspace.com Snell Expires February 22, 2008 [Page 21] Internet-Draft Atompub Features August 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Snell Expires February 22, 2008 [Page 22]