A facility for quotation covers the absence of original thought. --Dorothy L. Sayers, Lord Peter Wimsey in Gaudy Night
This chapter describes the RSS 2.0 specification in detail, how it works, and how it is created. It also explores RSS 2.0 predecessors--the largely compatible 0.91 and 0.92 specifications--and how they relate and can be converted to the latest standard.
Bringing Things Up to Date
RSS 2.0 has a long history. As was shown in Chapter 1, it's based on a succession of specifications: RSS 0.91, 0.92, 0.93, and 0.94. Because of this history and because of a lack of any adequate documentation for many of these standards, there is a massive gulf between the quality of the document you can produce and the quality of what you might have to parse. In other words, many people are doing it wrong.
This confusion forces this chapter to address two different issues. The first is how to create a perfectly specification-compliant feed, and the second is how to deal with feeds produced by those with less exacting standards.
This decision brings us to another one: what to do about the older versions that led to 2.0? The answer is this: although many people are still learning to produce 0.91, 0. 91, et al, we will not. You'll learn how to parse them, but from now on, as far as the simple strain of syndication feeds goes, we'll be creating only 2.0 feeds.
With that decided, steel yourself, visit the official specification document for RSS 2.0 at http://blogs.law.harvard.edu/tech/rss, and let's get on with it.