If I want to stop following someone, I believe I should send an Undo whose object is the Follow that I sent them in the past. Likewise, if I want to rescind permission to follow me, I should either Reject the Follow they originally sent me or perhaps Undo my Accept.
In all those cases, I need a reference to a potentially very old activity to be the object of my new activity. How can I find that within a client-to-server implementation?
activitypub-express works, I am actually looking up those old Follows whenever I’m fetching
Followers collections, but spec says those endpoints return actors rather than activities, so the activity id I need does not reach the client.
The only other option I see that is strictly C2S spec would be to crawl my inbox or outbox page-by-page until I find the Follow I seek, but this could be a really long journey.
Am I missing something obvious? If I implement a custom unfollow endpoint, is my implementation no longer a true Client-to-Server AP implementation?