crates/application/Cargo.toml

@@ -11,6 +11,8 @@ uuid        = { workspace = true }
 chrono      = { workspace = true }
 sha2        = "0.10"
 hex         = "0.4"
+tracing     = { workspace = true }
+url         = { workspace = true }
 
 [dev-dependencies]
 tokio  = { workspace = true, features = ["full"] }

crates/application/src/services/federation_event.rs

@@ -2,7 +2,7 @@ use domain::{
     errors::DomainError,
     events::DomainEvent,
     models::thought::{Thought, Visibility},
-    ports::{OutboundFederationPort, ThoughtRepository, UserRepository},
+    ports::{ActivityPubRepository, OutboundFederationPort, ThoughtRepository, UserRepository},
     value_objects::ThoughtId,
 };
 use std::sync::Arc;
@@ -12,6 +12,8 @@ pub struct FederationEventService {
     pub users: Arc<dyn UserRepository>,
     pub ap: Arc<dyn OutboundFederationPort>,
     pub base_url: String,
+    pub federation_action: Arc<dyn domain::ports::FederationActionPort>,
+    pub ap_repo: Arc<dyn ActivityPubRepository>,
 }
 
 impl FederationEventService {
@@ -112,6 +114,49 @@ impl FederationEventService {
                     .await
             }
 
+            DomainEvent::FetchRemoteActorPosts {
+                actor_ap_url,
+                outbox_url,
+            } => {
+                let notes = match self
+                    .federation_action
+                    .fetch_outbox_page(outbox_url, 1)
+                    .await
+                {
+                    Ok(n) => n,
+                    Err(e) => {
+                        tracing::warn!(outbox_url, error = %e, "failed to fetch remote outbox");
+                        return Ok(());
+                    }
+                };
+
+                let actor_url = url::Url::parse(actor_ap_url)
+                    .map_err(|e| DomainError::ExternalService(e.to_string()))?;
+
+                let author_id = self.ap_repo.intern_remote_actor(&actor_url).await?;
+
+                for note in notes {
+                    let ap_id = match url::Url::parse(&note.ap_id) {
+                        Ok(u) => u,
+                        Err(_) => continue,
+                    };
+                    let _ = self
+                        .ap_repo
+                        .accept_note(
+                            &ap_id,
+                            &author_id,
+                            &note.content,
+                            note.published,
+                            note.sensitive,
+                            note.content_warning,
+                            "public",
+                        )
+                        .await;
+                }
+
+                Ok(())
+            }
+
             _ => Ok(()),
         }
     }
@@ -126,7 +171,7 @@ mod tests {
         events::DomainEvent,
         models::thought::{Thought, Visibility},
         models::user::User,
-        ports::OutboundFederationPort,
+        ports::{ActivityPubRepository, OutboundFederationPort},
         testing::TestStore,
         value_objects::*,
     };
@@ -208,6 +253,8 @@ mod tests {
             users: Arc::new(store.clone()),
             ap: spy,
             base_url: "https://example.com".to_string(),
+            federation_action: Arc::new(store.clone()),
+            ap_repo: Arc::new(store.clone()),
         }
     }
 
@@ -531,4 +578,18 @@ mod tests {
 
         assert!(spy.updated.lock().unwrap().is_empty());
     }
+
+    #[tokio::test]
+    async fn fetch_remote_actor_posts_is_noop_when_outbox_empty() {
+        let store = TestStore::default();
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::FetchRemoteActorPosts {
+                actor_ap_url: "https://mastodon.social/users/alice".into(),
+                outbox_url: "https://mastodon.social/users/alice/outbox".into(),
+            })
+            .await
+            .unwrap();
+        // TestStore.fetch_outbox_page returns Ok(vec![]) — no notes, no error
+    }
 }

crates/worker/src/factory.rs

@@ -4,6 +4,7 @@ use std::sync::Arc;
 use activitypub::ThoughtsObjectHandler;
 use activitypub_base::ActivityPubService;
 use application::services::{FederationEventService, NotificationEventService};
+use domain::ports::{ActivityPubRepository, FederationActionPort, OutboundFederationPort};
 use postgres::activitypub::PgActivityPubRepository;
 use postgres_federation::{PostgresApUserRepository, PostgresFederationRepository};
 
@@ -34,7 +35,7 @@ pub async fn build(
     ));
 
     // ActivityPub service (for federation fan-out)
-    let ap_service: Arc<dyn domain::ports::OutboundFederationPort> = Arc::new(
+    let ap_service = Arc::new(
         ActivityPubService::new(
             Arc::new(PostgresFederationRepository::new(pool.clone())),
             Arc::new(PostgresApUserRepository::new(
@@ -54,6 +55,10 @@ pub async fn build(
         .await
         .expect("ActivityPubService build failed"),
     );
+    let ap_outbound = ap_service.clone() as Arc<dyn OutboundFederationPort>;
+    let ap_federation = ap_service.clone() as Arc<dyn FederationActionPort>;
+    let ap_repo_worker =
+        Arc::new(PgActivityPubRepository::new(pool.clone())) as Arc<dyn ActivityPubRepository>;
 
     // Application services
     let notification_svc = Arc::new(NotificationEventService {
@@ -63,8 +68,10 @@ pub async fn build(
     let federation_svc = Arc::new(FederationEventService {
         thoughts,
         users,
-        ap: ap_service,
+        ap: ap_outbound,
         base_url: base_url.to_string(),
+        federation_action: ap_federation,
+        ap_repo: ap_repo_worker,
     });
 
     // Thin handlers