Content Syndication with RSS

Chapter 9. Using Feeds

Words ought to be a little wild for they are the assaults of thought on the unthinking.

—John Maynard Keynes

Creating your own feed is good fun, but surely the real point of RSS is using feeds created by others. In this chapter, we’ll show how to incorporate other RSS 0.9x feeds within your own site, using techniques that you can also build into applications.

To use a feed you must first parse it—i.e., convert it from RSS into something more immediately useful to your program. The result may be something that a browser can display, data to be fed into a database, or variables to be used immediately. RSS feeds, because they are in XML, are parsable in many different ways, and the method you use depends on what you want to do with the feed and what sort of access you have to the machine doing the work.

The most common use of RSS feeds is incorporation into web sites, so that’s where we’ll start.

Using RSS Feeds Inside Another Site

Because RSS feeds change independently of the rest of the content within your page, the most sensible method of displaying the feed is to treat it as an inclusion. There are two ways of doing this: as a server-side include (SSI), in which your server inserts the parsed RSS feed into the correct place inside your page, or as a client-side include, in which you rely on your user’s browser to do the same.

Server-side inclusion depends on settings within your server’s configuration. If you have neither control of your own server, nor a friendly ...