codingphobia

This is a two part series in which I would explain a bit how can we generate Syndication feed using Asp.Net MVC and Syndication framework. first part will look into how to implement basic structure and second part will explain about how can we use a single line check and generate any type of feed, like Atom, Rss or another as per requirement.

I will start with a custom ActionResult named as FeedActionResult

public class FeedActionResult : ActionResult
{
  public SyndicationFeed Feed { get; set; }
}

We need our FeedActionResult to return our feed as an Object of Type ActionResult. Here is how we do this.

        public ActionResult GetFeed()
        {
            SyndicationFeed feed =
                   new SyndicationFeed("codingphobia.com Feed",
                                       "This is a feed from codingphobia.com",
                                       new Uri("http://codingphobia.com/feed/"),
                                       "somefeedID",
                                       DateTime.Now);
            SyndicationItem item1 =
                new SyndicationItem("Linq To XML: Generate Types with Nested Types using C#",
                                   "This is the content for Test item2",
                                    new Uri("http://codingphobia.com/2010/03/12/linq-to-xml-generate-types-with-nested-types-using-c/"),
                                   "TestItemID",
                                   DateTime.Now);

            List<SyndicationItem> items = new List<SyndicationItem>();

            items.Add(item1);
            feed.Items = items;

            return new FeedActionResult() { Feed = feed };
        }

As ActionResult is an abstract class, we need to provide implementation for the ExecuteResult method which is as follows

        public override void ExecuteResult(ControllerContext context)
        {
            context.HttpContext.Response.ContentType = "application/rss+xml";

            Rss20FeedFormatter rssFormatter = new Rss20FeedFormatter(Feed);
            using (XmlWriter writer = XmlWriter.Create(context.HttpContext.Response.Output))
            {
                 rssFormatter.WriteTo(writer);
            }
        }

Now we can call FeedActionResult.GetFeed() from our Controller, dedicated for processing requests for Feeds. Here is how we do this

    public class FeedController : Controller
    {
        // GET: /Feed/
        public ActionResult Index(string format)
        {
            return new FeedActionResult().GetFeed();
        }
    }

I have used action method Index(string format) with as string parameter here. This will help us to receive requests, for both Atom and Rss based Formats. We will look into this in later Post.

Following is the route settings in the global.asx file

routes.MapRoute(
                "Feed", // Route name
                "{controller}/{action}/{type}", // URL with parameters
                new { controller = "Feed", action = "Index", type = UrlParameter.Optional }
            );