**** This is not yet an Internet Draft. It has not yet been submitted *** A.Daviel INTERNET-DRAFT Vancouver Webpages March 1997 (Expires Sept. 1997) HTTP and HTML Metadata Schema Registration Status of this Memo This document is an Internet-Draft. 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.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet- Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Abstract This memo describes a method of registering Metadata schemes for use in HTML documents and other objects distributed over the World-Wide-Web in a distributed, hierarchical fashion, ensuring that metadata names are not used by different organisations for different purposes. 1. Introduction Objects distributed on the World-Wide-Web using the HTTP protocol, or written in HTML markup language, may have metadata associated with them. Where consensus is obtained on the meaning of particular metadata names, Web traversing agents may usefully extract information from and infer relationships between Web objects. To avoid conflicting uses of the same names, a registration scheme is proposed, prefixing the metadata element name with one or more schema fields. 2. Application Metadata may be associated with an object either directly, where the metadata is contained within the object, or indirectly, where the object contains a link to another object containing metadata. Within an HTML document, embedded metadata may be contained within a META tag, while indirect metadata may be referred to with a LINK or A (anchor) tag, depending on whether the link is made visible to the user. Within the HTTP header of a Web object, embedded metadata may be included in entity-header fields, and indirect metadata may be referred to using a Link entity-header. 3. Metadata Naming Convention Structured metadata names should take the form "schema" "." *( "schema" "." ) "element-name" Indirect metadata link should use the prefix "META". Examples: DC.creator - A document author using the Dublin Core schema. DAV.LockInfo - Lock information using the WEBDAV schema MCF.genls_pos - Relative position usning the MCF schema UMO.CS1.weight - Weight using the CS1 schema from the University of Mordor META.MCF - Link to metadata using the MCF schema. In these examples, the top-level schemas (DC, DAV, MCF and UMO) are registered with a naming authority. The registering organisation then defines the meaning of the names within that schema, and may optionally define sub-schema. Here, the University of Mordor Comp. Sci. department defines the CS1 schema. The IANA could be used as the top-level registration authority. 4. Schema Discovery While an agent could go to the naming authority to obtain details of a schema, it may be desirable for this information to be available via a link in the object. The prefix SCHEMA may be used to define such a link. 5. Examples In the head of an HTML document: In the body of an HTML document: Metacontent In the http header of a Web object: Content-Type: image/jpeg DC.Title: A view of Mount Rushmore DC.Creator: Arthur Upright Link: ; rel="SCHEMA.DC" Link: ; rel="META.MCF" The REL attribute specifies the relationship to the current document, so that it is clear that the MCF file contains metacontent for this document, and not some other one. 6. Schema-less metadata There are currently several metadata names in common use whose meaning is fairly clear and unambiguous. These include: Generator - The name and version of the authoring software Author - The author's name Copyright - A short statement of copyright and date. Description - A description of the object content. Keywords - Key words associated with the document for search purposes. together with several restricted-content metadata whose operation is well-defined, such as "Refresh", "Robots". The natural language and charset of these may be assumed to be that of the object itself, as given in the Content-Language and Content-Type headers or as requested during negotiation. The creation of new, schema-less metadata names is deprecated, especially ones which may be generated in conflicting versions depending on the user's cultural background, such as date, geographic position or physical quantities such as velocity or mass. 7. Author's Address A.Daviel Vancouver Webpages Box 357 185-9040 Blundell Rd Richmond BC V6Y 1K3 Tel. (604)-377-4796 Fax. (604)-270-8285 mailto:andrew@vancouver-webpages.com