I don' see how using header will remove the need to fetch the resources, parse them and diff them. Maybe you'll do that less often, but you'll still do it a lot...
Re:RSS mistakes: let's not make them again
by jrochkind1 on Friday July 19, 2013 @12:15AM
(#6068297)
Are you familiar with how HTTP caching headers work?
From an etag in the header, you can tell if the current remote resource is identical to the one you have locally or not, without any fetching/parsing/diffing.
Same with from a Last-Modified header, right?
In fact, you send a conditional GET rather than first retrieving only a HEAD and then deciding whether to continue with a full GET, but either way you aren't fetching/parsing/diffing to tell if there's new content.
Um, less solutions to this exist, but they are much simpler than 'PubSubHubbub or RSSCloud'. And don't require any changes to RSS.
You are requesting this thing over HTTP. You (and the server delivering the feed) simply need to use standard HTTP caching headers. etags, last-modified, etc.
No need to fetch the XML and parse it and diff it.