crates/adapters/activitypub-base/src/service.rs

@@ -1599,6 +1599,20 @@ impl domain::ports::FederationActionPort for ActivityPubService {
 
         Ok(notes)
     }
+
+    async fn fetch_actor_urls_from_collection(
+        &self,
+        _collection_url: &str,
+    ) -> Result<Vec<String>, domain::errors::DomainError> {
+        Ok(vec![])
+    }
+
+    async fn resolve_actor_profiles(
+        &self,
+        _urls: Vec<String>,
+    ) -> Vec<domain::models::actor_connection_summary::ActorConnectionSummary> {
+        vec![]
+    }
 }
 
 #[cfg(test)]

crates/adapters/event-payload/src/lib.rs

@@ -72,6 +72,12 @@ pub enum EventPayload {
         actor_ap_url: String,
         outbox_url: String,
     },
+    FetchActorConnections {
+        actor_ap_url: String,
+        collection_url: String,
+        connection_type: String,
+        page: u32,
+    },
 }
 
 impl EventPayload {
@@ -93,6 +99,7 @@ impl EventPayload {
             Self::UserUnblocked { .. } => "users.unblocked",
             Self::UserRegistered { .. } => "users.registered",
             Self::FetchRemoteActorPosts { .. } => "federation.fetch_outbox",
+            Self::FetchActorConnections { .. } => "federation.fetch_connections",
         }
     }
 }
@@ -209,6 +216,17 @@ impl From<&DomainEvent> for EventPayload {
                 actor_ap_url: actor_ap_url.clone(),
                 outbox_url: outbox_url.clone(),
             },
+            DomainEvent::FetchActorConnections {
+                actor_ap_url,
+                collection_url,
+                connection_type,
+                page,
+            } => Self::FetchActorConnections {
+                actor_ap_url: actor_ap_url.clone(),
+                collection_url: collection_url.clone(),
+                connection_type: connection_type.clone(),
+                page: *page,
+            },
         }
     }
 }
@@ -334,6 +352,17 @@ impl TryFrom<EventPayload> for DomainEvent {
                 actor_ap_url,
                 outbox_url,
             },
+            EventPayload::FetchActorConnections {
+                actor_ap_url,
+                collection_url,
+                connection_type,
+                page,
+            } => DomainEvent::FetchActorConnections {
+                actor_ap_url,
+                collection_url,
+                connection_type,
+                page,
+            },
         })
     }
 }
@@ -419,6 +448,12 @@ mod tests {
                 actor_ap_url: "https://mastodon.social/users/alice".into(),
                 outbox_url: "https://mastodon.social/users/alice/outbox".into(),
             },
+            EventPayload::FetchActorConnections {
+                actor_ap_url: "https://mastodon.social/users/alice".into(),
+                collection_url: "https://mastodon.social/users/alice/followers".into(),
+                connection_type: "followers".into(),
+                page: 1,
+            },
         ];
         let mut subjects: Vec<&str> = samples.iter().map(|p| p.subject()).collect();
         subjects.sort();

crates/domain/src/events.rs

@@ -64,6 +64,12 @@ pub enum DomainEvent {
         actor_ap_url: String,
         outbox_url: String,
     },
+    FetchActorConnections {
+        actor_ap_url: String,
+        collection_url: String,
+        connection_type: String,
+        page: u32,
+    },
 }
 
 pub struct EventEnvelope {

crates/domain/src/models/actor_connection_summary.rs

@@ -0,0 +1,7 @@
+#[derive(Debug, Clone)]
+pub struct ActorConnectionSummary {
+    pub url: String,
+    pub handle: String,
+    pub display_name: Option<String>,
+    pub avatar_url: Option<String>,
+}

crates/domain/src/models/connection_type.rs

@@ -0,0 +1,14 @@
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum ConnectionType {
+    Followers,
+    Following,
+}
+
+impl ConnectionType {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Self::Followers => "followers",
+            Self::Following => "following",
+        }
+    }
+}

crates/domain/src/models/mod.rs

@@ -1,4 +1,6 @@
+pub mod actor_connection_summary;
 pub mod api_key;
+pub mod connection_type;
 pub mod feed;
 pub mod notification;
 pub mod remote_actor;

crates/domain/src/ports.rs

@@ -194,6 +194,31 @@ pub trait RemoteActorRepository: Send + Sync {
     async fn find_by_url(&self, url: &str) -> Result<Option<RemoteActor>, DomainError>;
 }
 
+#[async_trait]
+pub trait RemoteActorConnectionRepository: Send + Sync {
+    async fn upsert_connections(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+        actors: &[crate::models::actor_connection_summary::ActorConnectionSummary],
+    ) -> Result<(), DomainError>;
+
+    async fn list_connections(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<Vec<crate::models::actor_connection_summary::ActorConnectionSummary>, DomainError>;
+
+    async fn connection_page_age(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<Option<chrono::DateTime<chrono::Utc>>, DomainError>;
+}
+
 #[async_trait]
 pub trait FederationActionPort: Send + Sync {
     async fn lookup_actor(&self, handle: &str) -> Result<RemoteActor, DomainError>;
@@ -214,6 +239,16 @@ pub trait FederationActionPort: Send + Sync {
         outbox_url: &str,
         page: u32,
     ) -> Result<Vec<crate::models::remote_note::RemoteNote>, DomainError>;
+
+    async fn fetch_actor_urls_from_collection(
+        &self,
+        collection_url: &str,
+    ) -> Result<Vec<String>, DomainError>;
+
+    async fn resolve_actor_profiles(
+        &self,
+        urls: Vec<String>,
+    ) -> Vec<crate::models::actor_connection_summary::ActorConnectionSummary>;
 }
 
 #[async_trait]

crates/domain/src/testing.rs

@@ -575,6 +575,52 @@ impl FederationActionPort for TestStore {
     ) -> Result<Vec<crate::models::remote_note::RemoteNote>, DomainError> {
         Ok(vec![])
     }
+
+    async fn fetch_actor_urls_from_collection(
+        &self,
+        _collection_url: &str,
+    ) -> Result<Vec<String>, DomainError> {
+        Ok(vec![])
+    }
+
+    async fn resolve_actor_profiles(
+        &self,
+        _urls: Vec<String>,
+    ) -> Vec<crate::models::actor_connection_summary::ActorConnectionSummary> {
+        vec![]
+    }
+}
+
+#[async_trait]
+impl RemoteActorConnectionRepository for TestStore {
+    async fn upsert_connections(
+        &self,
+        _actor_url: &str,
+        _connection_type: &str,
+        _page: u32,
+        _actors: &[crate::models::actor_connection_summary::ActorConnectionSummary],
+    ) -> Result<(), DomainError> {
+        Ok(())
+    }
+
+    async fn list_connections(
+        &self,
+        _actor_url: &str,
+        _connection_type: &str,
+        _page: u32,
+    ) -> Result<Vec<crate::models::actor_connection_summary::ActorConnectionSummary>, DomainError>
+    {
+        Ok(vec![])
+    }
+
+    async fn connection_page_age(
+        &self,
+        _actor_url: &str,
+        _connection_type: &str,
+        _page: u32,
+    ) -> Result<Option<chrono::DateTime<chrono::Utc>>, DomainError> {
+        Ok(None)
+    }
 }
 
 #[async_trait]
@@ -851,6 +897,25 @@ mod federation_port_tests {
             .unwrap();
         assert!(notes.is_empty());
     }
+
+    #[tokio::test]
+    async fn test_store_resolve_actor_profiles_returns_empty() {
+        let store = TestStore::default();
+        let result = store
+            .resolve_actor_profiles(vec!["https://example.com/users/alice".into()])
+            .await;
+        assert!(result.is_empty());
+    }
+
+    #[tokio::test]
+    async fn test_store_fetch_collection_urls_returns_empty() {
+        let store = TestStore::default();
+        let urls = store
+            .fetch_actor_urls_from_collection("https://example.com/users/alice/followers")
+            .await
+            .unwrap();
+        assert!(urls.is_empty());
+    }
 }
 
 #[cfg(test)]