FR: prune unregistered torrents

[Cringely]

This feature has had some interest over the years but I haven't found any forks of this plugin that implement it. Would you be willing and able to?

omaralvarez#21

[laur89]

It certainly is a useful idea.
Guess it should be coupled with also a timeframe (maybe optionally?), eg if state = error AND has been in this state for the past X hours to avoid false positives from one-off erroneous tracker update.

As different trackers may have their own statuses, I suppose it should be a user-defined regex.

Not sure I'd implement this before #4 though, especially the rule engine bit. Also it's highly unlikely I'll be able to keep the UI updated as I don't have enough GTK expertise, plus am not interested in it personally anyways - editing config files directly is less error-prone and simpler.