Automatic Feed Validation

The recent discussions
about how strict aggregators should be when reading invalid or ill
formed feeds (e.g. RSS or Atom) brought to mind an idea: an
automatic service that checks your feed for validity and send
e-mail whenever it finds a problem. The service would be an aide to
web site authors, alerting them to any problems with their RSS/Atom
feeds. Rather than authors manually checking their feeds with the
, the service would do this for them automatically.
Rough thoughts on some of the details:

  • Web front-end for sign-up, including feed URL, e-mail address,
    and frequency of checking the feed

  • Back-end processing would run on regular intervals, obtaining
    feeds that had changed and checking them with a local copy of the
    feed validator

  • Fetching of feeds should use minimal bandwidth by using ETags,
    If-Modified-Since, etc.

  • Data storage would be fairly minimal; no need to keep the entire
    downloaded feed data, just a hash perhaps

  • Notification runs like a state machine: only send e-mail when
    state changes (good feed goes bad, for example)

This approach wouldn’t solve the entire problem, but might be
useful as one more tool for the author who wants his/her data to
meet the standards. Tying more validation directly into web and
weblog authoring tools would also help. The nice thing about this
solution is support regardless of platform or tools being used. A
site that already does lots of feed downloading and parsing (like
Syndic8 or Bloglines) might be a good candidate for such a