F
@julian I tested out a root post that mentioned a PieFed community, and it got there okay - it's viewable at https://pythag.net/c/sci_fi (and federated out okay to another PieFed instance at https://palaver.p3x.de/c/sci_fi@pythag.net)
My guess as to why Lemmy might not like it is that the activity contains:
"audience": "https://community.nodebb.org/category/-1"
It looks like Lemmy tries to fetch that and can't parse the response.
@rikudou Yeah, sorry, I didn't mean to derail this thread. The GitHub issue was intended to only really be about the 'cc' problem, because it looks like PieFed will have to start sending Create/Note to non-Lemmy platforms anyway, but it'd easier if 'cc' doesn't have to be artificially included to keep NodeBB happy.
@julian Oh, I've just realised I read Nutomic's PR the wrong way around. After 2.0, you'll start getting Notes from them. If 'ChatMessage' processing isn't worth handling by NodeBB, I can change PieFed to send you Notes instead.
@julian I've added support to PieFed to successfully receive Create / Note as a PM from NodeBB.
From Nutomic's PR, it looks like you'll continue you get Create / ChatMessage from them, as also you will from PieFed. This currently fails, as I guess that it converts them into a Create / Note, but then complains of there being no 'cc'.
It doesn't make sense for PMs to be 'carbon copied' to anyone, so I'll raise an Issue at your repo.
@freamon Update: no, Lemmy doesn't understand them either. It rejects Create / Note without a community with the usual "did not match any variant of untagged enum AnnouncableActivities"
@julian It currently doesn't. If someone is Mentioned, the assumption is that it was part of post / comment in a community, and it fails because it can't find the community. I know that, for Lemmy, if you Mention someone in a comment, and they don't have a copy of the community (or they do and there's no local subscribers to it), then it will reject it. I don't know what it does if there's no community at all (I'll figure out a way to test it, on a server I can control).
@julian Oh, right. Thanks. But yeah, it's what Lemmy (and PieFed) uses, so I just assumed it was part of AP, and never looked into it any further.
I was thinking while typing this "I bet that means that chat messages from NodeBB to PieFed will fail", which I just tested, and sure enough they do (I'll make an Issue for it on PieFed's repo).
@rikudou As far as I understand things, a 'private message' in ActivityPub is Create / ChatMessage, not Create / Note. I think NodeBB wouldn't be the only software to complain if 'cc' is missing from either part of Create / Note (although it's not expected in either part of Create / ChatMessage).
Guppe Announces the original post, and the replies to it, but doesn't Announce anything else. For the replies, it also does what PeerTube does and sends out them unsigned, for instances to verify using the LD signature in the activity, or to fetch from the source. If you want to meaningfully vote on something that came from a.gup.pe, you have to send it to the original author, not to a.gup.pe like you would if you were voting from something from Lemmy, because a.gup.pe will just silently drop it.
Lemmy's communities Announce everything, but Mastodon only comprehends Announce as a Boost, so it just rejects the Announce of anything that's not a Page or a Note. There are other platforms though (e.g. Friendica) who will see the Announce of a Like, and go fetch it from it's source (most non-Lemmy platforms don't trust Lemmy-style Announces, because whilst it's against the spec for Announce contents not to be an exact copy of the original activity, there's nothing stopping a rogue community from misrepresenting users or undoing their intentions).
@julian Hi. Your reply won't have made it back, because of this issue - NodeBB is putting the wrong actor in the activity.
It's not a PieFed issue, pretty much all other federated platforms will reject activities if it's wrong. For example, on Lemmy, this post never made it there: https://lemmy.ml/c/activitypub@community.nodebb.org?dataType=Post&sort=New
OP's post was Announced by NodeBB as this:
{
"@context": "https://www.w3.org/ns/activitystreams",
"actor": "https://piefed.social/u/GroupNebula563",
"cc": [
"https://piefed.social/u/GroupNebula563",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "https://community.nodebb.org/post/https%3A%2F%2Fpiefed.social%2Fpost%2F468827#activity/announce/1739242064700",
"object": {
"@context": [
"https://www.w3.org/ns/activitystreams",
"https://w3id.org/security/v1"
],
"actor": "https://piefed.social/u/GroupNebula563",
"audience": "https://community.nodebb.org/category/30",
"cc": [],
"id": "https://piefed.social/activities/create/ZBBVVw3sp3wAdZ3",
"object": {
"attachment": [],
"attributedTo": "https://piefed.social/u/GroupNebula563",
"audience": "https://community.nodebb.org/category/30",
"cc": [],
"commentsEnabled": true,
"content": "<p>PieFed is very similar to Lemmy, but with a couple small differences that a couple people prefer. It se ems to be retrieving the community okay, we'll see if this post goes through.</p>\n",
"id": "https://piefed.social/post/468827",
"language": {
"identifier": "en",
"name": "English"
},
"mediaType": "text/html",
"name": "Test from PieFed!",
"nsfl": false,
"published": "2025-02-11T02:47:42.609106+00:00",
"sensitive": false,
"source": {
"content": "PieFed is very similar to Lemmy, but with a couple small differences that a couple people prefer. It see ms to be retrieving the community okay, we'll see if this post goes through.",
"mediaType": "text/markdown"
},
"stickied": false,
"tag": [],
"to": [
"https://community.nodebb.org/category/30",
"https://www.w3.org/ns/activitystreams#Public"
],
"type": "Page"
},
"to": [
"https://community.nodebb.org/category/30",
"https://www.w3.org/ns/activitystreams#Public"
],
"type": "Create"
},
"to": [
"https://community.nodebb.org/category/30/followers"
],
"type": "Announce"
}
The first 'actor' is wrong - it shouldn't be https://piefed.social/u/GroupNebula563, because you don't have the privkey to Announce anything as that user, and for them to send the activity to https://community.nodebb.org/category/30/followers doesn't make sense. The first 'actor' should be https://community.nodebb.org/category/30, which it was before a recent change.
Likewise, your reply was sent out as:
{
"@context": "https://www.w3.org/ns/activitystreams",
"actor": "https://community.nodebb.org/uid/2",
"cc": [
"https://community.nodebb.org/uid/2",
"https://www.w3.org/ns/activitystreams#Public"
],
"id": "https://community.nodebb.org/post/103212#activity/announce/1739244715728",
"object": {
"actor": "https://community.nodebb.org/uid/2",
"cc": [
"https://community.nodebb.org/uid/2/followers",
"https://piefed.social/u/GroupNebula563"
],
"id": "https://community.nodebb.org/post/103212#activity/create/1739244715677",
"object": {
"@context": [
"https://www.w3.org/ns/activitystreams",
{
"Emoji": "toot:Emoji",
"toot": "http://joinmastodon.org/ns#"
}
],
"attachment": [],
"attributedTo": "https://community.nodebb.org/uid/2",
"audience": "https://community.nodebb.org/category/30",
"cc": [
"https://community.nodebb.org/uid/2/followers",
"https://piefed.social/u/GroupNebula563"
],
"content": "<p><a href="\"https://piefed.social/u/GroupNebula563\"">@groupnebula563@piefed.social</a> the message was received! Hello! :smile:</p>\n",
"context": "https://community.nodebb.org/topic/07a57511-3b8b-4efd-a496-88824f72dbaa",
"id": "https://community.nodebb.org/post/103212",
"inReplyTo": "https://piefed.social/post/468827",
"name": "Re: Test from PieFed!",
"published": "2025-02-11T03:31:54.966Z",
"replies": "https://community.nodebb.org/post/103212/replies",
"source": {
"content": "[[@groupnebula563@piefed.social](https://community.nodebb.org/user/groupnebula563%40piefed.social)](https://community.nodebb.org/user/groupnebula563%40piefed.social) the message was received! Hello! :smile:",
"mediaType": "text/markdown"
},
"summary": null,
"tag": [
{
"href": "https://piefed.social/u/GroupNebula563",
"name": "[@groupnebula563@piefed.social](https://community.nodebb.org/user/groupnebula563%40piefed.social)",
"type": "Mention"
},
{
"icon": {
"mediaType": "image/png",
"type": "Image",
"url": "https://community.nodebb.org/assets/plugins/nodebb-plugin-emoji/emoji/android/1f604.png?v=70fb7184b74"
},
"id": "https://community.nodebb.org/assets/plugins/nodebb-plugin-emoji/emoji/android/1f604.png?v=70fb7184b74",
"name": ":smile:",
"type": "Emoji"
}
],
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"https://piefed.social/u/GroupNebula563"
],
"type": "Note",
"updated": null,
"url": "https://community.nodebb.org/post/103212"
},
"to": [
"https://www.w3.org/ns/activitystreams#Public",
"https://piefed.social/u/GroupNebula563"
],
"type": "Create"
},
"to": [
"https://community.nodebb.org/category/30/followers"
],
"type": "Announce"
}
https://community.nodebb.org/category/30, because whilst you do have the privkey for https://community.nodebb.org/uid/2 it's not you that's Announcing this, it's the category. In Mastodon terms, an Announce is a Boost, so this activity is saying that you're Boosting your own post, which also doesn't make sense.@julian I like how PeerTube does it. Looking at https://tilvids.com/c/thelinuxexperiment_channel/videos, for example, there's 2 intersecting squares next to the channel name, and clicking that puts the handle into my clipboard, for pasting into the box that I can then use on my instance to fetch it.
@julian I just ran into this. I guessed that the 'shortname' for https://forum.wedistribute.org/category/6/the-decentered-podcast would be 'the-decentered-podcast' but trying to fetch !the-decentered-podcast@forum.wedistribute.org didn't work, because it's actually just 'decentered'. I don't think that there's a way for anybody just looking at HTML representation to know this.
The AP from NodeBB is missing the 'name' field for images (where alt-text is put). If you inspect that first image in a web browser, the alt-text reads "Pic of a flow battery development kit ...", but for the relevant AP, compare NodeBB with a random image on pixelfed:
curl -L -H 'accept: application/activity+json' https://fbrc.nodebb.com/post/8 | jq .attachment[0]
vs.
curl -L -H 'accept: application/activity+json' https://pixelfed.de/p/tercean/364 | jq .attachment[0]
@julian Awesome, thanks.
Hopefully Announce / Update isn't similarly afflicted! (I realise that activity is the source of its own Issue, so I haven't seen any yet).
Looks like I was wrong before: whilst it's true that Lemmy isn't always great at sending an 'Accept' back, that's not the issue here. I was thinking about it from the perspective of a Person following a Group, not a Group following a Group.
It'll be interesting to see how the Lemmy devs respond. It's not really relevant for PieFed, because I'm not sure that there's communities there that have enough activity to warrant syncing to a category, but I thought about what would happen if you tried, and it would fail. The follower would be checked to see if they are a Person, and the request would go no further if not (there's no handy error returned, though).
I'm not sure it would be possible to enable, with the way the database is currently set up. We have a 'community_member' table, that looks like:
pyfedi=# \d community_member
Table "public.community_member"
Column | Type | Collation | Nullable | Default
------------------+-----------------------------+-----------+----------+---------
user_id | integer | | not null |
community_id | integer | | not null |
is_moderator | boolean | | |
is_owner | boolean | | |
is_banned | boolean | | |
notify_new_posts | boolean | | |
created_at | timestamp without time zone | | |
Indexes:
"community_member_pkey" PRIMARY KEY, btree (user_id, community_id)
"ix_community_member_is_banned" btree (is_banned)
Foreign-key constraints:
"community_member_community_id_fkey" FOREIGN KEY (community_id) REFERENCES community(id)
"community_member_user_id_fkey" FOREIGN KEY (user_id) REFERENCES "user"(id)
So if the 'user_id' was actually a Group instead of a Person, then it would have a join to the wrong table.
Yeah, as mentioned - Lemmy is often quite bad at sending the 'Accept' back for a Follow. It's particularly the case if the instance hasn't heard of you before, because in the process of fetching your user and instance details, it 'forgets' about the Accept. Within Lemmy, everyone's sort of got into the habit of 'Subscribe / Unsubscribe / Subscribe'. (where the first 'subscribe' lets them get your details, and the second one actually gets an 'Accept' back.)
PieFed is more reliable at sending 'Accept' back, so it's maybe useful to check your logic from this end with a community from there, e.g. https://piefed.social/c/antisocialmedia
@julian It's happened a few more times. I picked the smallest - the html is here
The Announced activity was:
{
"@context": "https://www.w3.org/ns/activitystreams",
"actor": "https://community.nodebb.org/category/4",
"cc": [
"https://community.nodebb.org/category/4/followers"
],
"id": "https://community.nodebb.org/post/https%3A%2F%2Fcommunity.nodebb.org%2Fpost%2F102786#activity/announce/1737481723563",
"object": {
"cc": [
"https://community.nodebb.org/uid/29326/followers"
],
"id": "https://community.nodebb.org/post/102786#activity/create/1737481718170",
"object": {
"@context": [
"https://www.w3.org/ns/activitystreams",
{
"Emoji": "toot:Emoji",
"toot": "http://joinmastodon.org/ns#"
}
],
"attachment": [],
"attributedTo": "https://community.nodebb.org/uid/29326",
"audience": "https://community.nodebb.org/category/4",
"cc": [
"https://community.nodebb.org/uid/29326/followers"
],
"content": "<p>another validation</p>\n",
"context": "https://community.nodebb.org/topic/18551",
"id": "https://community.nodebb.org/post/102786",
"inReplyTo": null,
"name": "nodebb to mastodon",
"published": "2025-01-21T17:48:33.041Z",
"replies": "https://community.nodebb.org/post/102786/replies",
"source": {
"content": "another validation",
"mediaType": "text/markdown"
},
"summary": null,
"tag": [],
"to": [
"https://www.w3.org/ns/activitystreams#Public"
],
"type": "Note",
"updated": null,
"url": "https://community.nodebb.org/post/102786"
},
"to": [
"https://www.w3.org/ns/activitystreams#Public"
],
"type": "Create"
},
"to": [
"https://www.w3.org/ns/activitystreams#Public"
],
"type": "Announce"
}
Oh, wait. You might be able to ignore me. My post was Announced, and that one did have an 'actor' in the Create part, so maybe it was just something unusual about the particular post I got.
I subscribed to activitypub@community.nodebb.org earlier, and got my first post. The activity looked like:
{
"@context": "https://www.w3.org/ns/activitystreams",
"actor": "https://community.nodebb.org/category/30",
"cc": [
"https://community.nodebb.org/category/30/followers"
],
"id": "https://community.nodebb.org/post/https%3A%2F%2Fcommunity.nodebb.org%2Fpost%2F102768#activity/announce/1737427447686",
"object": {
"cc": [
"https://community.nodebb.org/uid/24276/followers"
],
"id": "https://community.nodebb.org/post/102768#activity/create/1737427442685",
"object": {
"@context": [
"https://www.w3.org/ns/activitystreams",
{
"Emoji": "toot:Emoji",
"toot": "http://joinmastodon.org/ns#"
}
],
"attachment": [],
"attributedTo": "https://community.nodebb.org/uid/24276",
"audience": "https://community.nodebb.org/category/30",
"cc": [
"https://community.nodebb.org/uid/24276/followers"
],
"content": "<p>Looking through my logs (snip).</p>\n",
"context": "https://community.nodebb.org/topic/18546",
"id": "https://community.nodebb.org/post/102768",
"inReplyTo": null,
"name": "User Agent Used for Federation?",
"published": "2025-01-21T02:43:57.558Z",
"replies": "https://community.nodebb.org/post/102768/replies",
"source": {
"content": "Looking through my logs (snip)",
"mediaType": "text/markdown"
},
"summary": null,
"tag": [],
"to": [
"https://www.w3.org/ns/activitystreams#Public"
],
"type": "Note",
"updated": null,
"url": "https://community.nodebb.org/post/102768"
},
"to": [
"https://www.w3.org/ns/activitystreams#Public"
],
"type": "Create"
},
"to": [
"https://www.w3.org/ns/activitystreams#Public"
],
"type": "Announce"
}
As you can see, there's an 'actor' in the Announce (for the community), and 'attributedTo' in the Note (for the user), but no 'actor' in the Create part. I've not seen this behaviour on any other platforms - there's always an 'actor', with the same value as the 'attributedTo' field in the Note.
I tried to reply to my account on another platform on post , but it didn't federate out (I don't know if having to wait for moderator approval affects this). Given that Announce normally just wraps the original object, it suggests that there'll also be no 'actor' in 'Create' when it's just 'Create/Note' being sent out, but I haven't been able to check. This is a bit inconvenient (for me at least), because I'm used to using that field to get the details of the user who signed the request, and it'll be a pain to have to dig into the Note's 'attributedTo' field to find it.