This is a report from the W3C Technical Architecture Group to the W3C membership on TAG activities from February, 2009 through mid-July, 2009.
The TAG has recently decided to focus primarily on three major areas of current interest:
Sections below discuss each of these, as well as TAG work in other areas.
In April, the TAG issued a First Public Working Draft Usage Patterns For Client-Side URI parameters, which explores the client-side use and manipulation of URIs for tracking the state of AJAX-style applications. No firm decision has been made as to whether this work should progress to full Recommendation status, but by publishing a formal First Public Working Draft we leave open the possibility. In conjunction with the publication, W3C has issued a Call for Exclusions for patents relating to this work. (See also the section below: Web Application Architecture.)
During the period covered by this report, the TAG held or participated in the following face-to-face meetings::
The TAG has begun to take an active role in helping the W3C to develop future versions of HTML. Areas of particular interest to the TAG include:
The TAG has had initial discussions of the above areas, and we have met with several of the other groups that are involved. Some examples of specific progress and TAG impact include:
The Web was initially a system for sharing documents, typically in HTML. Languages like Javascript were used occasionally to provide somewhat more dynamic rendering, or for aids to navigation. In recent years, a new class of Web applications has emerged. The browser is now used as a container for applications that may execute for extended periods, that integrate information from diverse sources, and that provide users with the ability to navigate among states while remaining in the same application. Some of these applications also store information for offline use. HTML is used not as a representation of an individual document, but as a framework for hosting complex program logic, which is typically coded in Javascript.
Not surprisingly, these new Web applications raise many architectural issues: What does the URI that "launched" the application identify, and how should URIs be used as the application presents new information to the user? How can security and privacy be maintained as these applications access and integrate information from multiple sources?
At its June, 2009 F2F meeting, the TAG decided to begin a more comprehensive exploration of the ways that Web architecture should evolve to support such Web Applications. An initial list of topics for exploration was assembled and discussed. and progress on some of these is discussed immediately below.
As noted above, the TAG issued a First Public Working Draft Usage Patterns For Client-Side URI parameters, which explores the client-side use and manipulation of URIs to track the state of AJAX-style applications. We will probably not revise this draft significantly in the next few months. Instead, we will focus on other issues relating to Web Application architecture, in the hope that those investigations will inform our work on this draft when we do return to it.
The TAG has discussed a number of security issues, including issues relating to cross-origin access capabilities. Our goal at this stage is to ensure that we have a realistic understanding of the pertinent issues, and that we become familiar with technologies such as Caja that may help address security problems.
See also the discussion of privacy below under APIs.
As applications make increasing use of scripting, browser and other platform capabilities are exposed to those scripts through APIs. The TAG has begun to explore a number of questions relating to such APIs, including:
The TAG has also considered issues relating to some proposed APIs. In particular, we have begun to investigate concerns that have arisen regarding the relationship of W3C work on Geolocation APIs to the IETF's work on GEOPRIV.
Several years ago, the TAG investigated the use of HTTP redirection as a means of accessing metadata relating to a Web resource. Recently, the TAG has broadened its focus to include other means of accessing metadata, and also representation formats for metadata.
The TAG has during this period discussed several topics relating to metadata access on the Web. These include:
The TAG also discussed the note Uniform Access to Metadata, by Phil Archer and Jonathan Rees.
The TAG is also interested in the formats and vocabularies that are used to encode and transmit metadata. At its June, 2009 face-to-face meeting, the TAG agreed to start work on a TAG Finding on this topic.
In addition the primary focus areas discussed above, the TAG did work in several other areas:
The TAG continued its explorations of URIs, URNs, URI schemes, and in particular the suitability of the http URI scheme in situations where flexible registration and naming semantics are required. Henry Thompson prepared a revised draft Dirk and Nadia design a naming scheme - or - Web naming schemes good practices, which was discussed at the June TAG face-to-face meeting.
An informal interest group has been attempting to establish formal semantics for the HTTP protocol. Phone calls are held several times per month, and discussion is held on the public-awwsw@w3.org (archives). Although this is not a formal effort of the TAG, it was inspired in part by discussions held at the TAG. Several TAG members participate regularly, and the TAG discusses the progress of this work from time to time.
The Technical Architecture Group (TAG) was created in February 2001. Three TAG participants are appointed by the Director and five TAG participants are elected by the Advisory Committee. The mission of the TAG is stewardship of the Web architecture. Included in this mission is building consensus around principles of Web architecture, resolving issues involving Web architecture, and helping to coordinate cross-technology architecture developments inside and outside W3C.
Details on TAG activities can be found from the TAG home page. The TAG meets weekly and sends summaries of its activity to the AC, Chairs, and public TAG mailing list (www-tag archive). The TAG welcomes public discussion of open issues, as well as proposals for new issues, on that same list. The TAG's previous report was published in February2009.
Following the TAG election results announced in January 2009, the TAG participants are:
Notes:
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