XSLT 2.0 Web Development: Elements of a Web Site. Pt. 1 | WebReference

XSLT 2.0 Web Development: Elements of a Web Site. Pt. 1

XSLT 2.0 Web Development: Elements of a Web Site. Pt. 1.

Reproduced from "XSLT 2.0 Web Development (Kirsanov)" by permission of Prentice Hall PTR. ISBN 0131406353, copyright 2004. All rights reserved. See http://www.phptr.com for more information.

River and bridge and street and square
   Lay mine, as much at my beck and call,
Through the live translucent bath of air,
   As the sights in a magic crystal ball.

Robert Browning, Old Pictures in Florence

This chapter is a practical complement for Chapter 2, “The source definition.” Having discussed the ins and outs of building a comprehensive and useful source definition, we’ll now look at how these rules can be applied to real-world source XML documents of a typical web site.

I cannot claim to cover everything: Your web site may well contain unique elements that won’t fit common schemes. Here, only the most general and frequently used constructs are covered, and the approaches described in this chapter may not be optimal for all situations. Many examples are given, but rather than copy them over, try to use the reasoning behind these examples to analyze your own constraints and requirements.

The first part of the chapter deals with markup constructs commonly used in page documents, including headings, paragraphs and paragraph-like elements, links, images and other non-XML objects, tables, and forms. Then we will analyze the master document (3.9) to find out what data it needs to store and what is the best XML representation for this data. The last section (3.10) presents complete summary examples of a page document, a master document, and a Schematron schema to validate them.

3.1. Page documents: top-level structures

In this and subsequent sections, we look at the informational core of a web page, stored in its own source document (page document). Peripheral components such as navigation, parameters of the site environment, and metadata are stored in the master document, the subject of 3.9.

3.1.1. Page metadata

Every XML document has a root element, and since we’re talking about page documents here, there’s no reason not to call this element page. Its attributes and children are the natural place to store the page’s metadata.

In addition to its primary content, each page document includes certain metadata. Some of it may end up as a visible part of the web page, some may be hidden in HTML metadata constructs (keywords and descriptions in meta elements), some may be used during transformation but not included in the resulting HTML code, and some may not be used at all except for reference or source annotation purposes. Common examples of metadata include page creation date, change log, author(s) and editor(s), copyright and licensing information, and the language of the page.

Note that only information specific to this particular page must be stored in it; if some metadata bits are shared by more than one page, their proper place is in the master document (3.9) and not in any of the page documents.

Page ID. The most important piece of metadata is the page’s unique identifier used to resolve internal links (3.5.3). However, we cannot store this identifier in the page itself, or we’ll have a catch-22 situation: We can get from the id to the page location, but to obtain the id we must access the page — that is, we must already know its location. Because of this, the proper place for the ids of all pages is in the site’s master document.

Page coordinates.The same applies to the information on the position occupied by this page in the site’s hierarchy. As we’ll see later (3.9.1.1), the branch of the site’s tree that this page is a leaf of is most naturally deduced from the site directory in the master document. Duplicating this information in the page document itself is unnecessary and prone to errors.

Everything else.Any other page metadata is normally stored in the page document. Simple values can be stored in attributes of the page’s root element. More complex constructs that require their own elements can be placed either directly under the root or inside an umbrella parent element (e.g., metadata) that is a child of the root element.

Existing vocabularies. RDF (1.1.5), besides being the cornerstone of the Semantic Web, can be used as a powerful tool for representing metadata in the traditional Web. It allows you to use standardized descriptors for common values such as author and date, but you can just as well define your own semantics for your unique metadata.


Created: March 27, 2003
Revised: May 17, 2004

URL: http://webreference.com/programming/xsltweb/1