Reading Feeds with XLINQ
I have done a number of projects that all parse RSS Feeds using XLINQ. Which in itself is awesome, and much easier than using old XML techniques. Where I would so something like
1: public static List<PhotoInfo> LoadLatestPictures()
2: {
3: try
4: {
5: var xraw = XElement.Load(MOST_RECENT);
6: var xroot = XElement.Parse(xraw.ToString());
7: var photos = (from photo in xroot.Element("photos").
8: Elements("photo")
9: select new PhotoInfo
10: {
11: ImageUrl =
12: string.Format(
13: "http://farm{0}.static.flickr.com/{1}/{2}_{3}_m.jpg",
14: (string)photo.Attribute("farm"),
15: (string)photo.Attribute("server"),
16: (string)photo.Attribute("id"),
17: (string)photo.Attribute("secret"))
18: }).Take(Constants.ROWS * Constants.COLUMNS);
19: return photos.ToList<PhotoInfo>();
20: }
21: catch (Exception e)
22: {
23: Trace.WriteLine(e.Message, "ERROR");
24: }
25: return null;
26: }
However today I found something even cooler.
Have a look at the code below.
1: using System.ServiceModel.Syndication;
2: using System.Xml;
3: using System.IO;
4: using System.Xml.Linq;
5:
6: public class DataService : IDataService
7: {
8: public SyndicationFeedFormatter GetGeoRSS()
9: {
10: var geoRss =
11: @"<?xml version='1.0' encoding='utf-8' ?>
12: <rss version='2.0'
13: xmlns:geo='http://www.w3.org/2003/01/geo/wgs84_pos#'
14: xmlns:georss='http://www.georss.org/georss'
15: xmlns:gml='http://www.opengis.net/gml'
16: xmlns:mappoint='http://virtualearth.msn.com/apis/annotate#'>
17: <channel>
18: <title>Mount Saint Helens - Mount Margaret Trail</title>
19: <link></link>
20: <description>Trailheads and campsites in the Mount
21: Margaret area of
22: Mount Saint Helens, WA</description>
23: <mappointIntlCode>cht</mappointIntlCode>
24: <item>
25: <title>Coldwater Lake</title>
26: <description>Formed by the 1980 eruption of
27: Mount St. Helens.</description>
28: <georss:polygon>46.31409 -122.22616 46.31113
29: -122.22968 46.31083 -122.23320 46.29802
30: -122.25877 46.29245 -122.26641 46.29286 -122.26392
31: 46.28746 -122.26744 46.28741 -122.26006
32: 46.29049 -122.25955 46.29120 -122.25620
33: 46.28924 -122.255430 46.30271 -122.23251
34: 46.31284 -122.22315
35: 46.31409 -122.22616</georss:polygon>
36: <icon>http://dev.live.com/virtualearth/sdk/
37: img/hiking_icon.gif</icon>
38: </item>
39: <item>
40: <title>Lakes Trailhead</title>
41: <description>This is where we started our hike,
42: just down the road from the visitor center.
43: You could also start at the visitor center.
44: </description>
45: <geo:lat>46.2913246</geo:lat>
46: <geo:long>-122.2658157</geo:long>
47: </item>
48: </channel>
49: </rss>";
50:
51: var xDoc = XDocument.Parse(geoRss);
52: var feed = SyndicationFeed.Load(xDoc.CreateReader());
53:
54: Rss20FeedFormatter feed2 = Rss20FeedFormatter(feed);
55: return feed2;
56: }
57: }
The thing to note here is the “SyndicationFeed” and “Rss20FeedFormatter” classes. How cool is that.
So when you a Rss20FeedFormatter object, you get properties to get straight to all the usual RSS things you would like to use, such as Feed.Items
This is very cool. I am constantly being surprised by just what .NET can do, it just goes to show you need to keep an eye on the namespaces. There are new ones in there all the time.
System.ServiceModel.Syndication Huh, well I’ll be.
Josh Smith said
am June 24 2008 @ 1:26 pm
I smell Times Reader all over those classes!
sacha barber said
am June 24 2008 @ 1:32 pm
actually the raw XLINQ stuff was from Marsa, and the RSS find was from a Virtual Earth API demo
Mathew Thomas said
am June 25 2008 @ 3:21 am
Do you have a full code example you could share? Thanks!
sacha said
am June 25 2008 @ 5:46 am
Sure you can get the stuff I noticed this in first, from here
http://blogs.msdn.com/publicsector/archive/2008/05/01/updated-virtual-earth-map-control-demo-code.aspx
which is a Virtual Earth demo, just download that and search the VS2008 solution for “Rss20FeedFormatter”, that should give you the project where its used.