Auto-detect feeds programatically

The feed of any blog or site can be detected by the link tag:

<link href="rss.xml" rel="alternate" type="application/rss+xml" />

This can be found using WebRequest / WebResponse objects like this:

            Uri uri = new Uri(url, UriKind.Absolute);
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(uri);

            HttpWebResponse res;
            try
            {
                res = (HttpWebResponse)req.GetResponse();
            }
            catch (WebException)
            {
                return bi;
            }

            string response = "";

            switch (res.StatusCode)
            {
                case HttpStatusCode.OK:
                    byte[] buffer = new byte[4096];
                    res.GetResponseStream().Read(buffer, 0, 4096);
                    response = System.Text.Encoding.UTF8.GetString(buffer);
                    break;
            }

Once the feed URL is found programmatically, it is easy to strip the entire XML and deserialize it as System.ServiceModel.Syndication.SyndicationFeed object. SyndicationFeed has a list of SyndicationItems which is nothing but the blogpost or news item

           XmlReader reader;
            try
            {
                reader = XmlReader.Create(feed);
            }
            catch
            {
               
                return;
            }

            SyndicationFeed synFeed = null;

            string type = blog.Attributes["Type"].Value;
            if (type == "ATOM")
            {
                Atom10FeedFormatter atom = new Atom10FeedFormatter();
                if (atom.CanRead(reader))
                {
                    atom.ReadFrom(reader);
                    synFeed = atom.Feed;
                }
            }
            else
            {
                Rss20FeedFormatter rss = new Rss20FeedFormatter();
                if (rss.CanRead(reader))
                {
                    rss.ReadFrom(reader);
                    synFeed = rss.Feed;
                }
            }