Verify if historical state value are already there from a binding,

Development Add-ons
1

Hello @all,

I’m not sure my title is very clear, so let me explain.

I’ve got an addon that exposes water consumption data retrieved from an API.
The API only allows retrieving 3 months of data per call.

Ideally, I would like to loop through multiple calls to initialize the historical data.
But of course, I don’t want to do that every time the binding starts.

My first idea was to verify if item has allready historical data.
But as far as I understand, it’s not good practice to request item states directly from a binding.

What would be a good way to handle this case?

Thanks,
Laurent

2

You can store in the properties of the thing the last timestamp retrieved

3

Hello Gael,

This can be an idea, but properties seems not to be persists after restart of openhab.
I use code like this one:

Map<String, String> props = this.editProperties();
props.put(“lastUpdate”, currentDate.toString());
this.updateProperties(props);

Do I miss something ? Try to search, but don’t find info about this.

Laurent.

4

Hello Laurent,
You might be right that properties may not persist for unmanaged things. I remind that some binding use local storage for such topics. I found at least thinq on my system storing data in /var/lib/openhab/thinq

5

Yes, already do this on another biding to store metadata information.
Will try like this.

Laurent.