I put my response to strypey here as i’m new to ActivityPub forum and can put more than 2 links :
Hi @strypey i’m not a backend dev of Solid but a user that build Apps that deal with Solid Pods.
And I’m not really aware of the problemeatics of ActivityPub
And here is a thing i’ve done (before reading ActivityPub concept and so i didn’t use all like outbox for example).
So I wanted to build a “social app” providing the user a way to post some data on his own space (his POD) and make a reference to it on a centralised POD.
So when I log to the app that you can find here
https://scenaristeur.github.io/compagent-tuto/
with my webId https://spoggy.solid.community/profile/card#me
and when I (or any authenticated user) post a “Spog”, the data is stored on my/his pod like here https://spoggy.solid.community/public/spoggy/activity.ttl using some activityStream vocabulary like https://www.w3.org/ns/activitystreams#actor .
there could also be attachement to deal with pic/vids, sounds
The post form as a checkbox option to push the post (or a reference to that post) on a “centralizing pod” https://agora.solid.community/public/spoggy/activity.ttl using some activitystreams vocabulary too. These are the post showed on the landing page of the app, and as you can see, there are post from differents people, that are stored on differents users pods.
This could be seen as a Node, I think ?
But there are no notion (for the moment ? ) of outbox, and pushing data from one POD to another, as I have seen with ActivityPub, if I remember.
A way to deal with it could perharps be something like the websockets that is provided by Solid : An activityPub server plugged to a websocket to https://agora.solid.community/public/spoggy/activity.ttl could make the link from Users POD to ActivityPub system but I’m not enough comfortable with activityPub to say more about it.
It is an example of what can be done on Solid., source can be found here https://github.com/scenaristeur/compagent-tuto
I’m working now on another version https://scenaristeur.github.io/salut/ , so If someone want to try some plug between Solid and ActivityPub, let me know, Iwould be happy to contribute.
PS : sorry for my frog eater english 