Content Syndication with RSS

Name

mod_aggregation

Synopsis

The Aggregation module plays a small but useful part in the life cycle of information passing through the Web. It allows news aggregators, such as Meerkat, Snewp, and so on (all covered in Chapter 12) to display the sources of their items. These services gather items from many other sources and group them by subject. mod_aggregation allows us to know where they originated.

This, of course, works over generations: as long as the mod_aggregation elements are respected, a Meerkat feed that uses a Snewp item from a Moreover feed that is itself an aggregation (for example) will still have the original source credited. As long as the mod_aggregation elements are left in place, the information is preserved. There is not, as yet, any feature for describing an aggregation history, however. You only know about the primary source.

Aggregators are the only people generating these elements — if you’re building such a system, consider including them. The act of parsing such elements, however, is good for everyone. One can easily envisage an HTML representation of an RSS 1.0 feed with a “link via x” section. This is already done manually by many weblog owners, so why not include the feature in your RSS parsing scripts?

Namespace

mod_aggregation takes ag: as its prefix and http://purl.org/rss/modules/aggregation as its identifying URI. Therefore, an RSS 1.0 root element that uses it should look like this:

<?xml version="1.0"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" ...