9.3. An RSS News Agent

While the Jabber clients available off the shelf are orientated toward receiving (and sending) messages from other people, the possibilities don't stop there, as is clear from the recipes we've seen already. In this recipe, we're going to build a Jabber component that retrieves news items from various sources on the Web and sends them on to Jabber users who have expressed an interest in receiving them. We're going to use the Web for our news sources, but they could just as easily be sources within a corporate intranet. The key thing is that the sources are available in a readily parseable format.

RSS (RDF^[5] Site Summary or, alternatively, Really Simple Syndication) is an XML format used for describing the content of a web site, where that site typically contains news items, diary entries, event information, or generally anything that grows, item by item, over time. A classic application of RSS is to describe a news site such as JabberCentral (http://www.jabbercentral.org). JabberCentral's main page (see Figure 9-5) consists of a number of news items—in the "Recent News" section—about Jabber and its developer community. These items appear in reverse chronological order, and each one is succinct, sharing a common set of properties:

^[5] RDF stands for "Resource Description Framework."