Reading RSS by publication date

Question

I want to build an RSS reader for twitter RSS feeds (c# .NET 3.5).

Getting a response from RSS web address and parsing it is very simple. (I did that with XmlDocument.Load("<RSS Feed>")).

The problem is that I need to get RSS items by publication date range. When loading the application, I want to get all the items since the last time the feeds have been downloaded.

How can I do this?

Does every RSS feed allow that? (Google reader is showing items even from the last year).

Answer 1

It comes down to two sources of data: what the feed currently provides, and what you have stored.

If the feed is only showing the 10 most recent, for example, there is nothing you can do to get the older data. The feed must provide it.

Google Reader runs a cronjob that checks feeds about every 3 hours. It then stores the items in a database for Google Reader to reference any time it needs.