Content Management and Distribution Using XML

Introduction

That's one of the reasons we've started a project on the Wireless Developer Network that will attempt to solve at least part of the problem of outputting content to a number of different formats. It's called XMLCast, and it basically takes content formatted in a tidy XML structure, parses it, and outputs the content in a number of different formats, such as HTML, simple HTML (for less robust browsers like those found on handheld devices), RSS, and of course, WML. We'll kick XMLCast off with this article and will follow up over the next several weeks by continually adding to the application. When we're done, you should have a good idea as to how you too can use XML to standardize data sharing and distribution between multiple applications, devices, or customers.

We've developed XMLCast using Microsoft's Active Server Pages. We chose ASP because of Microsoft's feature-rich XML parser, the simplistic nature of VBScript, and the fact that there are a whole bunch of web sites running on IIS out there. And on the plus side, it's not necessary to set the mime type (though you may want to do it anyway, in case you're serving regular .wml files) because we do it in the ASP script itself.

Click here to download the ASP Source File.

Quite essential to understanding XMLCast is a working understanding of what XML is and how it works. For everything you would ever need to know about XML, give xml.com a visit. Other than that, a good working knowledge of ASP, HTML, and WML will help you understand what we're doing in this application. (For ASP info, go to Microsoft's MSDN. For HTML info, W3C is a good place to start, and for WAP, look no farther than our very own WAP Tutorials.)

For simplicity, we're going to be using a news page as our content, but this application can be altered to allow for any sort of content, as long as you know the XML structure. Our news is made up of four basic elements:

• Heading
• Link
• Summary
• Paragraphs

The Heading section refers to the title of the news article, the Link is a unique identifier for each article so the full article can be retrieved from a "Summary" page. The Summary is a short description of the article that is listed on the Summary page. The 's are enclosed within a tag, mostly because for wml, XMLCast sends out each paragraph as a separate card. But we're getting ahead of ourselves, so let's have a look at the XML DTD and an example news xml document. Here's the news.dtd file: