[OSM-dev] Quick History Service
frederik at remote.org
Sat Apr 23 21:29:13 BST 2011
with the license change likely to occupy us for the next year or so,
the question "who has edited this object, and have they all agreed to
the new license?" will become more important for some use cases (most
notably editors). If you're only interested in one or two objects then
you can simply download thir history from the API and inspect that, but
if you want to quickly colour your editor screen in red/yellow/green
then that would probably overload the API.
I have built a narrowed-down database that keeps a list of all objects
and their editors. Because it keeps nothing else (no concise object
histories etc.), it is reasonably small and fast (the MySQL database
takes 55 GB on disk for all objects). Data is updated every minute.
There's a minimalistic API that allows you to query the database:
For the impatient, here is an example request that should already
explain how things work:
Documentation (with some important caveats!) and source code is
available via http://wtfe.gryph.de/.
I intend to operate this service until something more usable comes along
or until the license change is finished, whichever happens earlier. Feel
free to poll this service from inside an editor after you have
downloaded data from the OSM API.
I'm open to suggestions about improving the service (conditions apply:
anything that requires re-importing the history file will lead to a
three-day downtime, and anything increasing DB space by more than 30%
will hit the limit of this particular host). But anyone is welcome to
use the source and set up their own servers, too.
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