Web Services, Part V: XML and XSLT Programming

In this column we continue our series on Web services. In Part I, we introduced you to this hot topic. In Part II, we showed you how to call Web services. In Part III, we presented the WebService behavior and its four supported methods. In Part IV, we continued our coverage of the WebService behavior by describing its objects and properties. In this column, we dive into XML and XSLT. You probably know by now that Web services accept and return SOAP packets which are XML-based. When you receive an XML message, you need to understand the XML format and how to convert it to more readable presentation formats.

We'll start off by explaining why XML is so popular. We'll show you how to read XML and what the governing principles are in its hierarchy structure. More often than not, you will need to convert XML to HTML on the fly, using XSLT, the style definition file for the XML file. We'll demonstrate this process with our dummy "MyDVD Rental Store." We'll convert the raw data (in XML) about the store's performance in January, February, and March of 2001, to an attractive HTML table. During this process, we'll show you how to embed XML data in HTML templates, how to loop through XML tags, how to format numbers, how to sum them, how to define variables, and how to use conditional statements in XSLT.

In this column you will learn: