After restarting NodeBB, I can load the category, though. Maybe some deadlock on initial import of the community.

Not specifically that URL, no. Now I just tried it. It resulted in a deadlock in Postgres.

2025-04-08T12:42:10.933614676Z 2025-04-08 12:42:10.933 UTC [32590] DETAIL:  Process 32590 waits for ShareLock on transaction 35424413; blocked by process 32626.
2025-04-08T12:42:10.933621228Z 	Process 32626 waits for ShareLock on transaction 35424434; blocked by process 32590.
2025-04-08T12:42:10.933624695Z 	Process 32590: 
2025-04-08T12:42:10.933626920Z 	INSERT INTO "legacy_object" ("_key", "type")
2025-04-08T12:42:10.933629244Z 	SELECT k, $2::TEXT::LEGACY_OBJECT_TYPE
2025-04-08T12:42:10.933631398Z 	  FROM UNNEST($1::TEXT[]) k
2025-04-08T12:42:10.933633432Z 	    ON CONFLICT
2025-04-08T12:42:10.933635396Z 	    DO NOTHING
2025-04-08T12:42:10.933637329Z 	Process 32626: 
2025-04-08T12:42:10.933639423Z 	INSERT INTO "legacy_object" ("_key", "type")
2025-04-08T12:42:10.933641588Z 	SELECT k, $2::TEXT::LEGACY_OBJECT_TYPE
2025-04-08T12:42:10.933643603Z 	  FROM UNNEST($1::TEXT[]) k
2025-04-08T12:42:10.933645586Z 	    ON CONFLICT
2025-04-08T12:42:10.933647519Z 	    DO NOTHING
2025-04-08T12:42:10.933654783Z 2025-04-08 12:42:10.933 UTC [32590] HINT:  See server log for query details.
2025-04-08T12:42:10.933656978Z 2025-04-08 12:42:10.933 UTC [32590] CONTEXT:  while inserting index tuple (6227,69) in relation "legacy_object"
2025-04-08T12:42:10.933659042Z 2025-04-08 12:42:10.933 UTC [32590] STATEMENT:  
2025-04-08T12:42:10.933660966Z 	INSERT INTO "legacy_object" ("_key", "type")
2025-04-08T12:42:10.933663000Z 	SELECT k, $2::TEXT::LEGACY_OBJECT_TYPE
2025-04-08T12:42:10.933664863Z 	  FROM UNNEST($1::TEXT[]) k
2025-04-08T12:42:10.933666666Z 	    ON CONFLICT
2025-04-08T12:42:10.933668430Z 	    DO NOTHING

I've successfully managed to find and track https://sh.itjust.works/c/localllama from my instance. But when I try, for example, https://lemmy.world/c/technology, I can't find anything. These Lemmy communities DO, however, show up as users on my NodeBB instance. Is there something I'm doing wrong? I tried going directly to /category/@technology@lemmy.world too.

Does this refactoring also include changes to the synchronization of local + remote categories? Or is it still trying to follow Group actors as a Group, which Lemmy does not like?

@julian@community.nodebb.org said in NodeBB v4.0.0 — Federate good times, come on!:
Do we need need to refollow?

Out of curiosity: what plugin/setting does one need to use in order to get a header like the NodeBB.org forums? With the links up top.

@julian@community.nodebb.org said in NodeBB v4.0.0 — Federate good times, come on!:
> @projectmoon@forum.agnos.is careful with that though, not all tags are the same, some have a higher signal-to-noise ratio, but others would just be filled with garbage

I think the best way, then, would be to have rules that map various group actor URLs to categories, and possibly also tags. Nothing automatic. Only configured. Of course, once Lemmy fixes the ability of Group actors to follow other Group actors, this will be a non-issue.

One other possible solution, which is employed by Misskey et al., is a proxy actor. It's a special user that follows other users, and relays info within its own instance. It's used for doing things like adding a remote user to a list without directly following them. The proxy account follows the user, and then your local instance adds the remote user to your list. But all ActivityPub interactions go through the proxy user.

@julian@community.nodebb.org Thanks. Even something as simple as mappin topic tags to categories automatically would work I think.

@julian@community.nodebb.org said in NodeBB v4.0.0 — Federate good times, come on!:

I'm wondering, as a stopgap solution, would it make sense to have some kind of rules engine that allows topics coming in from the fediverse to automatically be moved to NodeBB categories? Kind of like a somewhat less elegant sync.

Edit: like automatically assigning incoming topics based on tags seems like a particularly easy solution?

I've just installed a new instance of NodeBB and it works beautifully. Some questions:

1. Is it possible for categories to follow Lemmy communities in their sync settings? I seem to be able to follow Lemmy communities, but the categories are stuck on pending.
2. Same for NodeBB categories. Can I sync my own category with remote NodeBB categories?

Edit: the URLs stuck on pending are giving "invalid-id" errors in the log. As in invalid activitypub ids. I pasted the URLs of some Lemmy communities and NodeBB categories.

Edit 2: Found the topic about this. https://community.nodebb.org/post/102818