Automatic discovery of RSS feeds JUN 03 2002
Now that all of kottke.org is in MT, I can start worrying what to do about things like RSS feeds. I've been following the developments concerning the automatic discovery of RSS feeds, written about extensively on dive into mark (more here and here). Basically, you insert the following code:
<link rel="alternate" type="application/rss+xml" title="RSS" href="url/to/rss/file">
into your Web page and then all an RSS aggregator needs to do is check that Web page for your RSS feed instead of you having to provide the aggregator with a specific URL. Pretty slick really.
However, I have a couple of concerns about how this works:
1. My understanding is that when a Web browser loads a page, it downloads all the documents referenced in the <link> tags. That's how stylesheets work. Does this mean that every time someone loads up my Web site, they're going to get this RSS file as well, whether they want it or not? For popular sites, depending on the size of the RSS file, that could add up to several megabytes in additional bandwidth...and possible additional bandwidth charges. Does the "rel" attribute being set to "alternate" take care of this?
2. Do the aggregators need to check my Web page each time they download the RSS file or are they going to cache the location and then only check the Web page once a week or so for a possible location update? Again, serving two files when only one is called for could get costly, especially if an aggregator is calling for it multiple times a day.
Can anyone shed some light on this?