how to share local data between WebView and iOS widget?

[folsze]

I am just wondering whether this is possible.

AFAIK Preferences writes to UserDefaults thus this might actually be possible?

BUT:
to share data between an iOS main app and its widget, you need to create a group and write into the UserDefaults of that group.

This is where I see a potential issue. Can the Preferences API in WebView-code write the values to a specific group that can then also be read by the specific widget extension group?

I am highly thankful for ANY insights for this. Currently I am not able to retrieve the value by key.

[folsze]

I think this is not possible, since the Preferences API always writes to Standard UserDefaults. Even when specifying group, which is just a prefix for the key, not a group for sharing between app & widget.

Is this possible for localStorage/sqlite maybe? Or would I need to write to an app group there too?

I simply need to share one integer between web view and widget and I do not know how to. I only read this post:

https://forum.ionicframework.com/t/will-app-clips-be-available-in-ionic/194768/10?u=folsze

Which says:
For accessing long-term data, SQLite would be great as it can easily be used both from Ionic and Native. I would avoid using Local Storage or IndexedDB.

so can SQLite really be used to read from a widget? Or do I need an app group there too, which cannot be targeted from the web view capacitor community sqlite plugin?

The comment from Ionic Max is from 2020...

[folsze]

Here is a minimum reproducible example repo where you can experiment fast. I did not manage to get any data sharing working in it though, currently it uses the preferences API failing to write into a specifc group from WebView to WidgetExtension:

https://github.com/folsze/write-preferences-web-read-user-defaults-ios

Just clickt he button "Click me to save "AAA" to preferences" when in mobile, this should save to preferences and the widget will try to read this