QGIS Python get current atlas page name

Question

I am trying to dive into Python programming in QGIS. I want to write an expression in my layout that returns some values depending on the current atlas feature.

What I need first, is to get the same value as I can get with @atlas_pagename - then I will use that to query another table and get the data I need. I guess what I need to do is to create some kind of atlas object that follows the atlas in the current layout and then I should be able to read the information I need from that, but I have so far not managed to find anything about that in the manuals I've found.

I have found how to make a new layout or new atlas, but how can I dig into the current one? (Using QGIS 3.6.1)

Answer 1

Well, found it myself:

@qgsfunction(args='auto', group='Custom')
def getpage(feature,parent):
    projectInstance= QgsProject.instance()
    projectLayoutManager = projectInstance.layoutManager()
    layout=projectLayoutManager.layoutByName('detaljkart-atlas')
    atl=layout.atlas()
    pg=atl.nameForPage(atl.currentFeatureNumber())
    return pg

A kludgy part is that I need to write the name of the layout - there may be a way of picking up the current layout - but then I would have to check if an atlas is defined for the layout.

(Yup, so far I have repeated the @atlas_pagename, but I have some further plans for this)