The “RSS”, “blogging”, “PODcasting”, “OPML” – these acronyms are becoming increasingly big in the technology world. Especially after Microsoft had announced about RSS support in the Longhorn err… Vista and IE7. The MSDN article mentions photo blogs, moblogs, and video blogs as well as calendar feeds. But wait a second. Why does it have to run on a desktop? I am pretty sure that all these usage scenarios are perfect fit Mobile devices as well. So here’s a hint for Mobile devices / developers teams at Microsoft – let’s extend the “RSS everywhere” paradigm to the Windows CE platform as well. Call me crazy, but I also think RSS feeds could become more then an XML over HTTP. RSS feeds and lists don’t have to be blogs. They could as well include any type of business information that needs to be updated on a regular basis. What prevents us to use RSS over different communication channels like UDP or TCP?
So having all these ideas in mind I have started on creation of Y.A.R.F (Yet Another RSS Framework). I know there’re a few .NET implementations available on the internet, but I didn’t like either of them – they’re not flexible or extensible enough. I wanted a framework that could be used on both .NetCF and full .NET, allowed usage of the configuration files and was able to process Atom feeds as well. So here it is – a technology preview of the OpenNETCF.Rss library. When designing the architecture for the framework I’ve tried to model it after a WSE which provides paradigms of “channels” or connections and “transports“ or protocols that’re used to transport the data. Here’s the class diagram of the OpenNETCF.Rss library:
When developing the OpenNETCF.Rss I’ve used some RSS and Atom parsing code from the most excellent Dare’s RSSBandit.
There're a few ways you can use this library to retreive a RSS feed.
1. Syncronously:
Feed feed = FeedEngine.Receive(new Uri(“http://myfeed/rss.aspx”));
2. Asyncronously through event handler:
FeedEngine.FeedReceived+=new FeedReceivedHandler(FeedEngine_FeedReceived);
…
FeedEngine.Subscribe(new Uri((“http://myfeed/rss.aspx”));
2. Asyncronously by providing an instance of your FeedReceiver:
public class MyFeedReceiver : FeedReceiver
{
Form1 form;
public AlexFeedReceiver(Form1 form)
{
this.form = form;
}
//Implement the Receive
public override void Receive(Feed feed)
{
form.ShowFeed(feed);
}
}
...
FeedEngine.Subscribe(new Uri("http://www.engadget.com/rss.xml"), new MyFeedReceiver(this));
I'll elaborate on the OpenNETCF.Rss design in a later posts.
The OpenNETCF.Rss is in no way complete. I am planning on adding more functionality like FeedStorage and communications channels. Please do not hesitate to comment on the design and implementation. The VS.NET solution includes test projects for the desktop and PPC device.
OpenNETCF.Rss.zip (406.65 KB)
Documentation.chm (100.58 KB)