Withdrawn entries

[Graham Parks <dtcd@xxxxxxx>]

I want my aggregrator to be able to tell the user whether an entry disappeared from the feed because it got too old, or because it was withdrawn*. Currently Shrook can only show still-in-the-feed/was-in-the-feed (it greys the titles), but the distinction the user probably wants is withdrawn/not-withdrawn. Also, a user might not want to see withdrawn entries at all (outdated news reports etc).

My first idea was to try loading the <link> each time an entry is no longer in the main feed to see if you get a 404, but that would waste bandwidth and wouldn't work all the time, and is one of those daft hacks I mentioned yesterday. More elegant solutions:
1) When an entry diasappears, ping the server with its id to ask if its still current.
2) Use the previous group of entries axis link thing Sam was talking about at the weekend, to check if that's where it went
3) Put the ids of a few previous entries at the bottom of the feed before they disappear completely. That way the client knows they weren't just withdrawn.
4) Forget the idea of a flat file feed and do the whole thing programmatically (cf POP), so you don't run into this problem in the first place.

2 seems viable (but requires the archive link to be present). 3 I can see being useful for other things too (eg it increases the time you can go on holiday for before the current file and the old file no longer overlap, which could be useful). 4 is about 10 years too late. Any better ideas?

Graham

(* or superceded by a different entry, which probably needs to be handled as a special case - for more complex non-blog CMSs I think it should be possible for an entry to superced another one without having the same id, but that's probably a separate discussion)