Resource Description Framework (RDF)

The Resource Description Framework, or RDF, is a technology that we're using in Mozilla to integrate and aggregate Internet resources.

In particular, it is currently being used for Aurora and SmartBrowsing. Aurora is a single UI widget for managing bookmarks, history, search results, file systems, ftp, sitemaps, ... All these "data types" are reflected into the RDF data model. SmartBrowsing is a mechanism that allows trusted third party services to supply metadata annotations for the pages you view as you browse around the Web.

RDF Documentation

In Fifty Words Or Less. A nickel description of what RDF is, and how it fits in to the Mozilla world. Comes complete with examples!

Back-End Architecture. A grandiose document that describes how the RDF back-end works in Mozilla. Eventually, this will have sample code that illustrates how to use the back-end directly as a client, as well as instructions and samples that illustrate how to write your own pluggable RDF data source.

How It Works With NGLayout. This document describes how RDF/XML gets pumped through NGLayout to create a bona fide content model that is compatible with the Level 1 Core DOM.

On Making A Content Model From A Graph. This document describes why it's hard to make a content model from a graph, and suggests some ways to deal with it. It's a plea for help and a call to arms for all you mathematician types out there.

Datasource Howto. A cookbook for creating a datasource.

Design Overview

• Flash Specification (Implementation details for Flash Panel)
• Aurora (UI philosophy)
• Smart Browsing and Related Links (RDF annotation services)
• Persistent Client Store (RDF database as 'super cookie')
• RDF Technical Overview (mostly accurate; some technical detail outdated)
• XML Application Types (brief note on when to use RDF versus XML)
• References - Links to other documents about RDF

Older documents (to be updated)

• XML in Mozilla (overview on Mozilla's XML implementation, role of RDF etc) (guha-1.gif figure is obsoleted by NGLayout though)
• The Mozilla History Project (overview of planned History RDF datasource; needs updating)

Code status, To Do Lists, Recent Changes...

• Browse the CVS source tree. The core of Mozilla's RDF implementation is in /mozilla/rdf/base/. RDF data sources are in /mozilla/rdf/datasource/.
• Changes to mozilla/rdf/* source today, this week, or this month.
• See /rdf/base/idl/ for IDL interface definitions describing the RDF API.
• Code to manipulate the RDF dumps of the Mozilla Open Directory can be found in /mozilla/rdf/opendir/ area.
• Search for RDF status reports

Older Roadmaps

• Roadmap for RDF in Navigator (April 1998) (ideas for the future; needs updating)
• State Of The Code (Obsolete coding 'to do' list)
• RDF Todo List (partially obsolete todo list, 1998) (needs updating)

Related Documentation

• XUL and RDF: The Implementation of the Application Object Model
• Aurora docs (configurable chrome spec, workspace spec and treeview spec). (status of these?)
• Browse the PICS source code in Mozilla. PICS is the Platform for Internet Content Selection, a technology on which RDF was originally based. See the W3C PICS site for details.
• Blue Sky: Intertwingle ("a potential project to make it easier to deal with a massive volume of personal messages: excavating, traversing, relating, reporting, annotating...")
• Blue Sky: Collaborative Bookmark Indexing
• The Netscape Netcenter 'My Netscape Network' is using an RDF vocabulary called RDF Site Summary for Web channel descriptions

Community

netscape.public.mozilla.rdf is the Mozilla RDF newsgroup, and mozilla-rdf@mozilla.org is an e-mail mirror. Another nice mailing list for RDF developers is rdf-dev@mailbase.ac.uk, which has more general (non-Mozilla) RDF traffic.

Original Documentation (Obsoleted)

The following documents describe the older RDF implementation in Mozilla, and are mostly obsolete since the move to use the new layout engine. For more information about this change in Mozilla, see the development roadmap.

• Core RDF API Description (1998) (Obsolete API; historical interest only)
• Implementing RDF Data Sources - Draft #1 (April 1998) (nice overview and walkthrough using the older (obsolete) API) (needs updating)
• HyperTree API (draft #1 April 6th 1998) (Obsoleted by NGLayout and XUL)
• Shack : NavCenter as an HTML Widget (obsolete; ideas fed into the XUL/NG-Layout approach to RDF data binding)

RDF Standards

RDF is in the process of being standardized by the W3C. For example, there is as yet no agreed RDF Query API. You can take a look at the public drafts and the Model and Syntax Recommendation that are accesible from http://www.w3.org/RDF/. You might also look at some proposals for RDF Query that were made at the Query Languages for the Web workshop.

We expect Mozilla's RDF implementation to track the evolving RDF standard as specified in future W3C Recommendations. The Model and Syntax spec is now finalised. Future work is likely on RDF Query mechanisms. The query mechanism in Mozilla should be compatible with anticipated future developments in this area...