At Moodlemoot UK 2019, I demoed a piece of work we'd done for QMUL to better integrate their Moodle and Mahara - https://www.youtube.com/watch?v=Ixy4Ah9webQ for the presentation - and said I'd talk to the Mahara team about getting it into core so I could then release the rest of it as plugins.
Essentially we made a few core hacks to 18.04 to support some additional behaviours around notifications sent to a user:
* ability to add extra parameters in the inbox URL to open a specific message
* call out to plugin functions if defined when a new notification is issued
* call out to plugin functions if defined when a notification is read
* call out to plugin functions if defined when a notification is deleted
These hook points would allow a plugin to optionally do something with these notifications, such as sending the notifications out to a Moodle webservice, or updating the Moodle when a notification is read in Mahara, and with a view to being as efficient as possible to avoid affecting those who don't have the integration set up.
I'll review the patches ASAP that I did for 18.04 to see what needs changing for 19.10 but I'd appreciate it if we could look at getting them in for that release and adding Behat tests for the first item, I don't think I can do anything for the others.
The functionality I'm looking at adding is explicitly giving options to plugin authors, not changing core Mahara behaviour in case that's a concern.
Here's the first bunch of patches, these represent the core functionality of letting notifications be passed to a plugin to do something additional with them.