[OSM-dev] Deleted objects

[Andy Allan]

On 19 February 2012 20:46, Frederik Ramm <frederik at remote.org> wrote:

> This requires some sort of "show me all deleted objects in this area" API
> call, and once that exists, editors could support it in some way. Potlatch 1
> already has an undelete function but uses a custom API that can not easily
> be re-used by other editors including P2.

Yes. I've been asking around for an undelete API for a couple of years
- it's got nothing to do with the license change though! It's the
major feature in Potlatch 1 that has not, and cannot[1], be
implemented in other editors right now.

> Has work already been done in that direction, or what kind of person would
> be required to do such work?

If talked to Matt Amos (zere) about it a few times, but he has been
planning some other changes to the way that history is stored that
would conflict with a naive implementation of this. I believe that the
naive implementation uses the fact that deleted items are still in the
current tables, marked as deleted, whereas there are plans to remove
deleted objects from the current tables and enforce things with
foreign keys. Obviously if this is done, then the undelete API would
need a major rethink to be based on the entity history tables.

However, there's not been much progress (that I'm aware of) on the
foreign-keys-related work, and we still need the undelete XML API!

Cheers,
Andy

[1] using the XML api. Technically if you want to do some AMF parsing,
the world is your oyster, but you'll have a bad (salty) taste left in
your mouth.