Detecting new new items in a RSS feed
atom-feed, feed, rss, xml
Solution
Each item in RSS 2 and Atom has a GUID/ID that may be flagged as unique. If it's flagged as unique you can use it to identify items and match against the previous items.
Problem
What is the best way to detect when a feed has been updated? Say I have an application which polls the feed every 15 minutes. How do I find out if new content has been added or not? For RSS as well as Atom feeds.