Okay, so you read the title of this post. Perhaps you're expecting huge amounts of code, but guess what. As it turns out, this is so ridiculously easy. This will be a very short post.

Step one is to have a method that loads an RSS feed. WCF offers a new class called SyndicationFeed.

private SyndicationFeed Load( string url )

{

  XmlReader reader = XmlReader.Create( url );

  SyndicationFeed feed = SyndicationFeed.Load( reader );

  return feed;

}

The above method will take a url and use to load a feed. Now suppose I have a list of urls and I want to take all the items in all the feeds, sort them and use them to generate a new, aggregated feed. Sounds like a fair amount of work, right.

Here is the code:

private SyndicationFeed Aggregate( List<string> urls )

{

  var items = from url in urls

              from item in Load( url ).Items

              orderby item.PublishDate descending

              select item;

  SyndicationFeed feed = new SyndicationFeed( items );

  return feed;

}

Cool!