This allows JsonHandlers to set a hash for certain API calls.
Clients can use this information to load data for such a call
from a cache instead of calling the method over the network
just to get the same result as last time.
Reasoning:
a) Currently, the API behaves inconsistently. While reconfiguring
a "justAdd" thing, it did call thingRemoved, however, reconfiguring a thing
that uses pairing did not.
b) The old implementation did not consider childs. Reconfiguring a
justAdd thing which has childs was calling thingRemoved on the parent only
but not its childs.
c) If we'd fix this by calling thingRemoved() for all flows and childs
we'd end up in hells kitchen as we can't know about the new state of childs
after the reconfiguration, so we can't just automatically add all the childs
back ourselves, the plugin needs to do that. This in turn would mean that
childs would get new ids which then breaks rules and stuff.
So the conclusion has been to just re-run the setup and the plugin implementation
is in charge for then checking the existing childs and calling autoThingDisappeared()
as needed.
WARNING: This also implies that we need to fix some plugins which currently rely
on thingRemoved to be called for reconfiguration and might create duplicate
connections or similar now.
This should have been already included in commit
8f5536ba1a2cc1f5bf96146b5f0469b5401f6585 Update copyright
Signed-off-by: Radek Dostál <radek.dostal@streamunlimited.com>
