Implement federated user following (fixes #752) (#2577)

[lemmy.git] / crates / apub / src / activities / community / mod.rs

diff --git a/crates/apub/src/activities/community/mod.rs b/crates/apub/src/activities/community/mod.rs
index aed7ddb902714b6e8a7f8c82bec054eb9b6f5527..d05a3d66c5bd28e80a83053c56560a90354cb726 100644 (file)
--- a/crates/apub/src/activities/community/mod.rs
+++ b/crates/apub/src/activities/community/mod.rs
@@ -2,11 +2,11 @@ use crate::{
   activities::send_lemmy_activity,
   activity_lists::AnnouncableActivities,
   local_instance,
-  objects::community::ApubCommunity,
+  objects::{community::ApubCommunity, person::ApubPerson},
   protocol::activities::community::announce::AnnounceActivity,
-  ActorType,
 };
 use activitypub_federation::{core::object_id::ObjectId, traits::Actor};
+use lemmy_db_schema::source::person::PersonFollower;
 use lemmy_utils::error::LemmyError;
 use lemmy_websocket::LemmyContext;
 use url::Url;
@@ -17,22 +17,47 @@ pub mod remove_mod;
 pub mod report;
 pub mod update;
 
-#[tracing::instrument(skip_all)]
-pub(crate) async fn send_activity_in_community<ActorT>(
+/// This function sends all activities which are happening in a community to the right inboxes.
+/// For example Create/Page, Add/Mod etc, but not private messages.
+///
+/// Activities are sent to the community itself if it lives on another instance. If the community
+/// is local, the activity is directly wrapped into Announce and sent to community followers.
+/// Activities are also sent to those who follow the actor (with exception of moderation activities).
+///
+/// * `activity` - The activity which is being sent
+/// * `actor` - The user who is sending the activity
+/// * `community` - Community inside which the activity is sent
+/// * `inboxes` - Any additional inboxes the activity should be sent to (for example,
+///               to the user who is being promoted to moderator)
+/// * `is_mod_activity` - True for things like Add/Mod, these are not sent to user followers
+pub(crate) async fn send_activity_in_community(
   activity: AnnouncableActivities,
-  actor: &ActorT,
+  actor: &ApubPerson,
   community: &ApubCommunity,
-  mut inboxes: Vec<Url>,
+  extra_inboxes: Vec<Url>,
+  is_mod_action: bool,
   context: &LemmyContext,
-) -> Result<(), LemmyError>
-where
-  ActorT: Actor + ActorType,
-{
-  inboxes.push(community.shared_inbox_or_inbox());
-  send_lemmy_activity(context, activity.clone(), actor, inboxes, false).await?;
+) -> Result<(), LemmyError> {
+  // send to extra_inboxes
+  send_lemmy_activity(context, activity.clone(), actor, extra_inboxes, false).await?;
 
   if community.local {
-    AnnounceActivity::send(activity.try_into()?, community, context).await?;
+    // send directly to community followers
+    AnnounceActivity::send(activity.clone().try_into()?, community, context).await?;
+  } else {
+    // send to the community, which will then forward to followers
+    let inbox = vec![community.shared_inbox_or_inbox()];
+    send_lemmy_activity(context, activity.clone(), actor, inbox, false).await?;
+  }
+
+  // send to those who follow `actor`
+  if !is_mod_action {
+    let inboxes = PersonFollower::list_followers(context.pool(), actor.id)
+      .await?
+      .into_iter()
+      .map(|p| ApubPerson(p).shared_inbox_or_inbox())
+      .collect();
+    send_lemmy_activity(context, activity, actor, inboxes, false).await?;
   }
 
   Ok(())