feat(frontend): followers/following tabs on remote actor profile with lazy loading + pagination

crates/adapters/activitypub-base/Cargo.toml

@@ -5,6 +5,7 @@ edition = "2024"
 
 [dependencies]
 tokio        = { workspace = true }
+futures      = { workspace = true }
 serde        = { workspace = true }
 serde_json   = { workspace = true }
 uuid         = { workspace = true }

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

@@ -1599,6 +1599,85 @@ 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> {
+        let resp: serde_json::Value = reqwest::Client::new()
+            .get(collection_url)
+            .header("Accept", "application/activity+json, application/ld+json")
+            .send()
+            .await
+            .map_err(|e| domain::errors::DomainError::ExternalService(e.to_string()))?
+            .json()
+            .await
+            .map_err(|e| domain::errors::DomainError::ExternalService(e.to_string()))?;
+
+        let empty = vec![];
+        let items = resp["orderedItems"].as_array().unwrap_or(&empty);
+        Ok(items
+            .iter()
+            .filter_map(|v| v.as_str().map(|s| s.to_string()))
+            .collect())
+    }
+
+    async fn resolve_actor_profiles(
+        &self,
+        urls: Vec<String>,
+    ) -> Vec<domain::models::actor_connection_summary::ActorConnectionSummary> {
+        use futures::future;
+
+        async fn fetch_one(
+            url: String,
+        ) -> Option<domain::models::actor_connection_summary::ActorConnectionSummary> {
+            let resp: serde_json::Value = tokio::time::timeout(
+                std::time::Duration::from_secs(5),
+                reqwest::Client::new()
+                    .get(&url)
+                    .header("Accept", "application/activity+json")
+                    .send(),
+            )
+            .await
+            .ok()?
+            .ok()?
+            .json()
+            .await
+            .ok()?;
+
+            let ap_url = resp["id"].as_str()?.to_string();
+            let preferred_username = resp["preferredUsername"].as_str().unwrap_or("").to_string();
+            let domain_str = url::Url::parse(&ap_url)
+                .ok()
+                .and_then(|u| u.host_str().map(|s| s.to_string()))
+                .unwrap_or_default();
+            let handle = format!("{}@{}", preferred_username, domain_str);
+            let display_name = resp["name"].as_str().map(|s| s.to_string());
+            let avatar_url = resp["icon"]["url"].as_str().map(|s| s.to_string());
+
+            Some(
+                domain::models::actor_connection_summary::ActorConnectionSummary {
+                    url: ap_url,
+                    handle,
+                    display_name,
+                    avatar_url,
+                },
+            )
+        }
+
+        let futs: Vec<_> = urls.into_iter().map(fetch_one).collect();
+        let results = future::join_all(futs).await;
+
+        results
+            .into_iter()
+            .filter_map(|r| {
+                if r.is_none() {
+                    tracing::warn!("failed to resolve actor profile (timeout or parse error)");
+                }
+                r
+            })
+            .collect()
+    }
 }
 
 #[cfg(test)]

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

@@ -4,6 +4,12 @@ where
 {
 }
 
+fn _assert_impl_federation_action_port_connections()
+where
+    crate::service::ActivityPubService: domain::ports::FederationActionPort,
+{
+}
+
 use super::*;
 use crate::repository::{Follower, FollowerStatus, RemoteActor};
 

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/adapters/postgres/migrations/006_remote_actor_connections.sql

@@ -0,0 +1,13 @@
+CREATE TABLE remote_actor_connections (
+    id                     UUID        PRIMARY KEY DEFAULT gen_random_uuid(),
+    actor_url              TEXT        NOT NULL,
+    connection_type        TEXT        NOT NULL,
+    page                   INT         NOT NULL,
+    connected_actor_url    TEXT        NOT NULL,
+    connected_handle       TEXT        NOT NULL,
+    connected_display_name TEXT,
+    connected_avatar_url   TEXT,
+    fetched_at             TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE(actor_url, connection_type, page, connected_actor_url)
+);
+CREATE INDEX ON remote_actor_connections(actor_url, connection_type, page, fetched_at);

crates/adapters/postgres/src/lib.rs

@@ -7,6 +7,7 @@ pub mod follow;
 pub mod like;
 pub mod notification;
 pub mod remote_actor;
+pub mod remote_actor_connections;
 pub mod tag;
 pub mod thought;
 pub mod top_friend;

crates/adapters/postgres/src/remote_actor_connections.rs

@@ -0,0 +1,110 @@
+use async_trait::async_trait;
+use domain::{
+    errors::DomainError, models::actor_connection_summary::ActorConnectionSummary,
+    ports::RemoteActorConnectionRepository,
+};
+use sqlx::PgPool;
+
+pub struct PgRemoteActorConnectionRepository {
+    pool: PgPool,
+}
+
+impl PgRemoteActorConnectionRepository {
+    pub fn new(pool: PgPool) -> Self {
+        Self { pool }
+    }
+}
+
+#[async_trait]
+impl RemoteActorConnectionRepository for PgRemoteActorConnectionRepository {
+    async fn upsert_connections(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+        actors: &[ActorConnectionSummary],
+    ) -> Result<(), DomainError> {
+        for actor in actors {
+            sqlx::query(
+                "INSERT INTO remote_actor_connections
+                    (actor_url, connection_type, page, connected_actor_url,
+                     connected_handle, connected_display_name, connected_avatar_url, fetched_at)
+                 VALUES ($1, $2, $3, $4, $5, $6, $7, NOW())
+                 ON CONFLICT(actor_url, connection_type, page, connected_actor_url)
+                 DO UPDATE SET
+                     connected_handle       = EXCLUDED.connected_handle,
+                     connected_display_name = EXCLUDED.connected_display_name,
+                     connected_avatar_url   = EXCLUDED.connected_avatar_url,
+                     fetched_at             = NOW()",
+            )
+            .bind(actor_url)
+            .bind(connection_type)
+            .bind(page as i32)
+            .bind(&actor.url)
+            .bind(&actor.handle)
+            .bind(&actor.display_name)
+            .bind(&actor.avatar_url)
+            .execute(&self.pool)
+            .await
+            .map_err(|e| DomainError::Internal(e.to_string()))?;
+        }
+        Ok(())
+    }
+
+    async fn list_connections(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<Vec<ActorConnectionSummary>, DomainError> {
+        #[derive(sqlx::FromRow)]
+        struct Row {
+            connected_actor_url: String,
+            connected_handle: String,
+            connected_display_name: Option<String>,
+            connected_avatar_url: Option<String>,
+        }
+        let rows = sqlx::query_as::<_, Row>(
+            "SELECT connected_actor_url, connected_handle, connected_display_name, connected_avatar_url
+             FROM remote_actor_connections
+             WHERE actor_url = $1 AND connection_type = $2 AND page = $3
+             ORDER BY connected_handle",
+        )
+        .bind(actor_url)
+        .bind(connection_type)
+        .bind(page as i32)
+        .fetch_all(&self.pool)
+        .await
+        .map_err(|e| DomainError::Internal(e.to_string()))?;
+
+        Ok(rows
+            .into_iter()
+            .map(|r| ActorConnectionSummary {
+                url: r.connected_actor_url,
+                handle: r.connected_handle,
+                display_name: r.connected_display_name,
+                avatar_url: r.connected_avatar_url,
+            })
+            .collect())
+    }
+
+    async fn connection_page_age(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<Option<chrono::DateTime<chrono::Utc>>, DomainError> {
+        let row: Option<(Option<chrono::DateTime<chrono::Utc>>,)> = sqlx::query_as(
+            "SELECT MAX(fetched_at) FROM remote_actor_connections
+             WHERE actor_url = $1 AND connection_type = $2 AND page = $3",
+        )
+        .bind(actor_url)
+        .bind(connection_type)
+        .bind(page as i32)
+        .fetch_optional(&self.pool)
+        .await
+        .map_err(|e| DomainError::Internal(e.to_string()))?;
+
+        Ok(row.and_then(|(ts,)| ts))
+    }
+}

crates/api-types/src/responses.rs

@@ -110,3 +110,20 @@ pub struct RemoteActorResponse {
     pub following_url: Option<String>,
     pub attachment: Vec<ProfileField>,
 }
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ActorConnectionResponse {
+    pub handle: String,
+    pub display_name: Option<String>,
+    pub avatar_url: Option<String>,
+    pub url: String,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ActorConnectionPageResponse {
+    pub items: Vec<ActorConnectionResponse>,
+    pub page: u32,
+    pub has_more: bool,
+}

crates/application/src/services/federation_event.rs

@@ -14,6 +14,7 @@ pub struct FederationEventService {
     pub base_url: String,
     pub federation_action: Arc<dyn domain::ports::FederationActionPort>,
     pub ap_repo: Arc<dyn ActivityPubRepository>,
+    pub remote_actor_connections: Arc<dyn domain::ports::RemoteActorConnectionRepository>,
 }
 
 impl FederationEventService {
@@ -157,6 +158,52 @@ impl FederationEventService {
                 Ok(())
             }
 
+            DomainEvent::FetchActorConnections {
+                actor_ap_url,
+                collection_url,
+                connection_type,
+                page,
+            } => {
+                let urls = match self
+                    .federation_action
+                    .fetch_actor_urls_from_collection(collection_url)
+                    .await
+                {
+                    Ok(u) => u,
+                    Err(e) => {
+                        tracing::warn!(
+                            collection_url,
+                            error = %e,
+                            "failed to fetch actor connections collection"
+                        );
+                        return Ok(());
+                    }
+                };
+
+                if urls.is_empty() {
+                    return Ok(());
+                }
+
+                let summaries = self.federation_action.resolve_actor_profiles(urls).await;
+
+                if summaries.is_empty() {
+                    return Ok(());
+                }
+
+                tracing::info!(
+                    count = summaries.len(),
+                    connection_type,
+                    actor = actor_ap_url,
+                    "caching actor connections"
+                );
+
+                self.remote_actor_connections
+                    .upsert_connections(actor_ap_url, connection_type, *page, &summaries)
+                    .await?;
+
+                Ok(())
+            }
+
             _ => Ok(()),
         }
     }
@@ -255,6 +302,7 @@ mod tests {
             base_url: "https://example.com".to_string(),
             federation_action: Arc::new(store.clone()),
             ap_repo: Arc::new(store.clone()),
+            remote_actor_connections: Arc::new(store.clone()),
         }
     }
 
@@ -592,4 +640,19 @@ mod tests {
             .unwrap();
         // TestStore.fetch_outbox_page returns Ok(vec![]) — no notes, no error
     }
+
+    #[tokio::test]
+    async fn fetch_actor_connections_is_noop_when_collection_empty() {
+        let store = TestStore::default();
+        let spy = Arc::new(SpyPort::default());
+        svc(&store, spy.clone())
+            .process(&DomainEvent::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,
+            })
+            .await
+            .unwrap();
+    }
 }

crates/bootstrap/src/factory.rs

@@ -8,6 +8,7 @@ use domain::{errors::DomainError, events::DomainEvent, ports::EventPublisher};
 use event_transport::EventPublisherAdapter;
 use nats::NatsTransport;
 use postgres::activitypub::PgActivityPubRepository;
+use postgres::remote_actor_connections::PgRemoteActorConnectionRepository;
 use postgres_federation::{PostgresApUserRepository, PostgresFederationRepository};
 use presentation::state::AppState;
 
@@ -111,6 +112,7 @@ pub async fn build(cfg: &Config) -> Infrastructure {
         events: event_publisher,
         federation: ap_service.clone() as Arc<dyn domain::ports::FederationActionPort>,
         ap_repo: Arc::new(PgActivityPubRepository::new(pool.clone())),
+        remote_actor_connections: Arc::new(PgRemoteActorConnectionRepository::new(pool.clone())),
     };
 
     Infrastructure { state, ap_service }

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)]

crates/presentation/src/handlers/federation_actors.rs

@@ -2,7 +2,10 @@ use crate::{
     errors::ApiError, extractors::OptionalAuthUser, handlers::feed::to_thought_response,
     state::AppState,
 };
-use api_types::requests::PaginationQuery;
+use api_types::{
+    requests::PaginationQuery,
+    responses::{ActorConnectionPageResponse, ActorConnectionResponse},
+};
 use application::use_cases::feed::get_user_feed;
 use axum::{
     extract::{Path, Query, State},
@@ -71,6 +74,85 @@ pub async fn remote_actor_posts_handler(
     })))
 }
 
+const CACHE_TTL_SECS: i64 = 3600;
+
+pub async fn actor_followers_handler(
+    State(s): State<AppState>,
+    Path(handle): Path<String>,
+    Query(q): Query<PaginationQuery>,
+) -> Result<Json<ActorConnectionPageResponse>, ApiError> {
+    actor_connections_handler(s, handle, "followers", q.page() as u32).await
+}
+
+pub async fn actor_following_handler(
+    State(s): State<AppState>,
+    Path(handle): Path<String>,
+    Query(q): Query<PaginationQuery>,
+) -> Result<Json<ActorConnectionPageResponse>, ApiError> {
+    actor_connections_handler(s, handle, "following", q.page() as u32).await
+}
+
+async fn actor_connections_handler(
+    s: AppState,
+    handle: String,
+    connection_type: &str,
+    page: u32,
+) -> Result<Json<ActorConnectionPageResponse>, ApiError> {
+    const PAGE_SIZE: usize = 20;
+
+    let actor = s.federation.lookup_actor(&handle).await?;
+
+    let collection_url = match connection_type {
+        "followers" => actor
+            .followers_url
+            .ok_or_else(|| ApiError::BadRequest("actor has no followers URL".into()))?,
+        _ => actor
+            .following_url
+            .ok_or_else(|| ApiError::BadRequest("actor has no following URL".into()))?,
+    };
+
+    let items = s
+        .remote_actor_connections
+        .list_connections(&actor.url, connection_type, page)
+        .await?;
+
+    let stale = match s
+        .remote_actor_connections
+        .connection_page_age(&actor.url, connection_type, page)
+        .await?
+    {
+        None => true,
+        Some(age) => chrono::Utc::now().signed_duration_since(age).num_seconds() > CACHE_TTL_SECS,
+    };
+
+    if stale {
+        let _ = s
+            .events
+            .publish(&DomainEvent::FetchActorConnections {
+                actor_ap_url: actor.url.clone(),
+                collection_url,
+                connection_type: connection_type.to_string(),
+                page,
+            })
+            .await;
+    }
+
+    let has_more = items.len() >= PAGE_SIZE;
+    Ok(Json(ActorConnectionPageResponse {
+        items: items
+            .into_iter()
+            .map(|a| ActorConnectionResponse {
+                handle: a.handle,
+                display_name: a.display_name,
+                avatar_url: a.avatar_url,
+                url: a.url,
+            })
+            .collect(),
+        page,
+        has_more,
+    }))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -127,6 +209,7 @@ mod tests {
             events: store.clone(),
             federation: store.clone(),
             ap_repo: store.clone(),
+            remote_actor_connections: store.clone(),
         }
     }
 

crates/presentation/src/handlers/notifications.rs

@@ -113,13 +113,15 @@ mod tests {
             hasher: Arc::new(NoOpHasher),
             events: store.clone(),
             federation: store.clone(),
+            ap_repo: store.clone(),
+            remote_actor_connections: store.clone(),
         }
     }
 
     fn app() -> Router {
         Router::new()
             .route("/notifications", patch(mark_all_read))
-            .route("/notifications/:id", patch(mark_notification_read))
+            .route("/notifications/{id}", patch(mark_notification_read))
             .with_state(make_state())
     }
 

crates/presentation/src/handlers/social.rs

@@ -186,6 +186,8 @@ mod tests {
             hasher: Arc::new(NoOpHasher),
             events: store.clone(),
             federation: store.clone(),
+            ap_repo: store.clone(),
+            remote_actor_connections: store.clone(),
         }
     }
 

crates/presentation/src/handlers/users.rs

@@ -275,6 +275,7 @@ mod tests {
             events: store.clone(),
             federation: store.clone(),
             ap_repo: store.clone(),
+            remote_actor_connections: store.clone(),
         }
     }
 

crates/presentation/src/routes.rs

@@ -69,6 +69,14 @@ pub fn router() -> Router<AppState> {
             "/federation/actors/{handle}/posts",
             get(federation_actors::remote_actor_posts_handler),
         )
+        .route(
+            "/federation/actors/{handle}/followers-list",
+            get(federation_actors::actor_followers_handler),
+        )
+        .route(
+            "/federation/actors/{handle}/following-list",
+            get(federation_actors::actor_following_handler),
+        )
         .route("/tags/popular", get(feed::get_popular_tags))
         .route("/tags/{name}", get(feed::tag_thoughts_handler))
         // notifications

crates/presentation/src/state.rs

@@ -21,4 +21,5 @@ pub struct AppState {
     pub events: Arc<dyn EventPublisher>,
     pub federation: Arc<dyn FederationActionPort>,
     pub ap_repo: Arc<dyn ActivityPubRepository>,
+    pub remote_actor_connections: Arc<dyn RemoteActorConnectionRepository>,
 }

crates/worker/src/factory.rs

@@ -6,6 +6,7 @@ use activitypub_base::ActivityPubService;
 use application::services::{FederationEventService, NotificationEventService};
 use domain::ports::{ActivityPubRepository, FederationActionPort, OutboundFederationPort};
 use postgres::activitypub::PgActivityPubRepository;
+use postgres::remote_actor_connections::PgRemoteActorConnectionRepository;
 use postgres_federation::{PostgresApUserRepository, PostgresFederationRepository};
 
 use crate::handlers::{FederationHandler, NotificationHandler};
@@ -59,6 +60,8 @@ pub async fn build(
     let ap_federation = ap_service.clone() as Arc<dyn FederationActionPort>;
     let ap_repo_worker =
         Arc::new(PgActivityPubRepository::new(pool.clone())) as Arc<dyn ActivityPubRepository>;
+    let actor_connections = Arc::new(PgRemoteActorConnectionRepository::new(pool.clone()))
+        as Arc<dyn domain::ports::RemoteActorConnectionRepository>;
 
     // Application services
     let notification_svc = Arc::new(NotificationEventService {
@@ -72,6 +75,7 @@ pub async fn build(
         base_url: base_url.to_string(),
         federation_action: ap_federation,
         ap_repo: ap_repo_worker,
+        remote_actor_connections: actor_connections,
     });
 
     // Thin handlers

docs/superpowers/specs/2026-05-15-actor-connections-design.md

@@ -0,0 +1,213 @@
+# Remote Actor Connections (Followers/Following) Design
+
+Display a remote actor's followers and following lists in the thoughts UI, with worker-backed caching and concurrent AP profile resolution.
+
+## Data Flow
+
+1. User opens the Followers or Following tab on a remote actor profile
+2. Frontend calls `GET /federation/actors/{handle}/followers-list?page=1`
+3. Backend returns cached data immediately (may be empty on first visit)
+4. If cache is empty OR older than 1 hour: publish `FetchActorConnections` event fire-and-forget
+5. Worker receives event → fetches remote collection page → concurrently resolves each actor URL to a profile → stores results
+6. Next visit / tab re-open shows populated data
+
+## Domain Changes
+
+### New models (`domain/src/models/`)
+
+**`connection_type.rs`**:
+```rust
+#[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" }
+    }
+}
+```
+
+**`actor_connection_summary.rs`**:
+```rust
+#[derive(Debug, Clone)]
+pub struct ActorConnectionSummary {
+    pub url: String,            // AP URL of the connected actor
+    pub handle: String,
+    pub display_name: Option<String>,
+    pub avatar_url: Option<String>,
+}
+```
+
+### New `DomainEvent` variant (`domain/src/events.rs`)
+
+```rust
+FetchActorConnections {
+    actor_ap_url: String,
+    collection_url: String,
+    connection_type: String,  // "followers" | "following"
+    page: u32,
+},
+```
+
+### New port (`domain/src/ports.rs`)
+
+```rust
+pub trait RemoteActorConnectionRepository: Send + Sync {
+    async fn upsert_connections(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+        actors: &[ActorConnectionSummary],
+    ) -> Result<(), DomainError>;
+
+    async fn list_connections(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<Vec<ActorConnectionSummary>, DomainError>;
+
+    async fn connection_page_age(
+        &self,
+        actor_url: &str,
+        connection_type: &str,
+        page: u32,
+    ) -> Result<Option<chrono::DateTime<chrono::Utc>>, DomainError>;
+}
+```
+
+### New `FederationActionPort` method
+
+```rust
+async fn resolve_actor_profiles(
+    &self,
+    urls: Vec<String>,
+) -> Vec<ActorConnectionSummary>;
+```
+
+Returns only successful resolutions. Per-actor timeout: 5 seconds. Concurrent. No error propagation — failures are silently skipped (warn logged).
+
+## Storage
+
+### Migration: `006_remote_actor_connections.sql`
+
+```sql
+CREATE TABLE remote_actor_connections (
+    id              UUID        PRIMARY KEY DEFAULT gen_random_uuid(),
+    actor_url       TEXT        NOT NULL,
+    connection_type TEXT        NOT NULL,
+    page            INT         NOT NULL,
+    connected_actor_url   TEXT  NOT NULL,
+    connected_handle      TEXT  NOT NULL,
+    connected_display_name TEXT,
+    connected_avatar_url   TEXT,
+    fetched_at      TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE(actor_url, connection_type, page, connected_actor_url)
+);
+CREATE INDEX ON remote_actor_connections(actor_url, connection_type, page, fetched_at);
+```
+
+### `PgRemoteActorConnectionRepository`
+
+- `upsert_connections`: `INSERT ... ON CONFLICT DO UPDATE SET connected_handle=EXCLUDED.connected_handle, connected_display_name=EXCLUDED.connected_display_name, connected_avatar_url=EXCLUDED.connected_avatar_url, fetched_at=NOW()`
+- `list_connections`: `SELECT * WHERE actor_url=$1 AND connection_type=$2 AND page=$3 ORDER BY connected_handle`
+- `connection_page_age`: `SELECT MAX(fetched_at) WHERE actor_url=$1 AND connection_type=$2 AND page=$3`
+
+## activitypub-base: `resolve_actor_profiles`
+
+`ActivityPubService` implements `FederationActionPort::resolve_actor_profiles`:
+
+1. For each URL: spawn `tokio::time::timeout(5s, fetch_actor_profile(url))`
+2. `fetch_actor_profile`: `GET {url}` with `Accept: application/activity+json` → parse `preferred_username`, `name`, `icon.url`, `id`
+3. Collect `Ok` results → return as `Vec<ActorConnectionSummary>`
+4. Failed/timed-out actors: `tracing::warn!` and skip
+
+## event-payload
+
+Add `FetchActorConnections { actor_ap_url, collection_url, connection_type, page }` to `EventPayload` — subject: `"federation.fetch_actor_connections"`. Add to `From<&DomainEvent>`, `TryFrom<EventPayload>`, and uniqueness test.
+
+## Worker
+
+`FederationEventService` gains `remote_actor_connections: Arc<dyn RemoteActorConnectionRepository>`.
+
+Handler for `FetchActorConnections { actor_ap_url, collection_url, connection_type, page }`:
+
+1. Fetch `collection_url` (as AP JSON) → extract `orderedItems` array as Vec of URL strings
+2. If empty: return Ok(()) — nothing to store
+3. `federation_action.resolve_actor_profiles(urls).await` — concurrent, partial success OK
+4. `remote_actor_connections.upsert_connections(actor_ap_url, connection_type, page, &results).await`
+5. Log: `tracing::info!(count = results.len(), "actor connections cached")`
+
+Wire `remote_actor_connections` in `worker/src/factory.rs`.
+
+## AppState + Bootstrap
+
+Add `remote_actor_connections: Arc<dyn RemoteActorConnectionRepository>` to `AppState`. Wire `PgRemoteActorConnectionRepository` in `bootstrap/src/factory.rs`.
+
+## REST Endpoints
+
+**`GET /federation/actors/{handle}/followers-list?page=1`**
+
+```
+1. lookup_actor(handle) → get actor_ap_url + followers_url
+2. list_connections(actor_ap_url, "followers", page) → cached items
+3. connection_page_age(...) → if None or > 1 hour: publish FetchActorConnections (fire-and-forget)
+4. Return { items: [...], page, has_more: items.len() == PAGE_SIZE }
+```
+
+`PAGE_SIZE = 20`. `has_more` tells the frontend whether to show a "next" button.
+
+**`GET /federation/actors/{handle}/following-list?page=1`** — identical, uses `following_url` and `"following"`.
+
+Response item shape (reuses `RemoteActorResponse` minus `bio`/`banner`/`attachment`/`outbox_url`):
+```json
+{ "handle": "...", "displayName": "...", "avatarUrl": "...", "url": "..." }
+```
+
+Define as a new `ActorConnectionResponse` in api-types.
+
+Mount both routes in `routes.rs`. Add new handler file `federation_actors.rs` (already exists — add to it).
+
+## Frontend
+
+### `lib/api.ts`
+
+```typescript
+export const ActorConnectionSchema = z.object({
+  handle: z.string(),
+  displayName: z.string().nullable(),
+  avatarUrl: z.string().nullable(),
+  url: z.string(),
+});
+export type ActorConnection = z.infer<typeof ActorConnectionSchema>;
+
+const ConnectionPageSchema = z.object({
+  items: z.array(ActorConnectionSchema),
+  page: z.number(),
+  hasMore: z.boolean(),
+});
+
+export const getActorFollowers = (handle, page, token) =>
+  apiFetch(`/federation/actors/${encodeURIComponent(handle)}/followers-list?page=${page}`, {}, ConnectionPageSchema, token);
+
+export const getActorFollowing = (handle, page, token) =>
+  apiFetch(`/federation/actors/${encodeURIComponent(handle)}/following-list?page=${page}`, {}, ConnectionPageSchema, token);
+```
+
+### `RemoteUserProfile` changes
+
+Replace the plain "Followers / Following" link section with two client-side tabs. Each tab:
+- Shows a list of `RemoteUserCard` components (reuse existing)  
+- "Load more" button if `hasMore`
+- Empty state: "Loading — check back soon."
+- Tab is lazy: only fetches when first opened (not on profile load)
+
+Use the existing `RemoteUserCard` component — it already handles follow button and linking.
+
+### `remote-user-profile.tsx` note
+
+The component is already a client component (`"use client"`), so React state for tab selection and paginated data works fine. Each tab fetches via `getActorFollowers`/`getActorFollowing` when first activated.

thoughts-frontend/components/remote-user-card.tsx

@@ -3,14 +3,19 @@
 import { useState } from "react";
 import { useAuth } from "@/hooks/use-auth";
 import Link from "next/link";
-import { followUser, RemoteActor } from "@/lib/api";
+import { followUser } from "@/lib/api";
 import { Button } from "@/components/ui/button";
 import { UserAvatar } from "@/components/user-avatar";
 import { toast } from "sonner";
 import { UserPlus } from "lucide-react";
 
 interface RemoteUserCardProps {
-  actor: RemoteActor;
+  actor: {
+    handle: string;
+    displayName: string | null;
+    avatarUrl: string | null;
+    url: string;
+  };
 }
 
 export function RemoteUserCard({ actor }: RemoteUserCardProps) {

thoughts-frontend/components/remote-user-profile.tsx

@@ -7,7 +7,9 @@ import { ThoughtList } from "@/components/thought-list";
 import { Card } from "@/components/ui/card";
 import { Button } from "@/components/ui/button";
 import { ExternalLink, UserPlus, UserMinus } from "lucide-react";
-import { followUser, unfollowUser, RemoteActor, Thought, Me } from "@/lib/api";
+import { followUser, unfollowUser, RemoteActor, Thought, Me, getActorFollowers, getActorFollowing, ActorConnection } from "@/lib/api";
+import { RemoteUserCard } from "@/components/remote-user-card";
+import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
 import { toast } from "sonner";
 import { useAuth } from "@/hooks/use-auth";
 
@@ -26,6 +28,17 @@ export function RemoteUserProfile({
   const [loading, setLoading] = useState(false);
   const { token } = useAuth();
 
+  type ConnectionTab = "posts" | "followers" | "following";
+  const [activeTab, setActiveTab] = useState<ConnectionTab>("posts");
+  const [followers, setFollowers] = useState<ActorConnection[]>([]);
+  const [following, setFollowing] = useState<ActorConnection[]>([]);
+  const [followersPage, setFollowersPage] = useState(1);
+  const [followingPage, setFollowingPage] = useState(1);
+  const [followersHasMore, setFollowersHasMore] = useState(false);
+  const [followingHasMore, setFollowingHasMore] = useState(false);
+  const [followersLoaded, setFollowersLoaded] = useState(false);
+  const [followingLoaded, setFollowingLoaded] = useState(false);
+
   const handleFollow = async () => {
     if (!token) {
       toast.error("You must be logged in to follow users.");
@@ -50,6 +63,30 @@ export function RemoteUserProfile({
     }
   };
 
+  const loadFollowers = async (page: number) => {
+    const result = await getActorFollowers(actor.handle, page, token).catch(() => null);
+    if (!result) return;
+    setFollowers((prev) => (page === 1 ? result.items : [...prev, ...result.items]));
+    setFollowersHasMore(result.hasMore);
+    setFollowersLoaded(true);
+    setFollowersPage(page);
+  };
+
+  const loadFollowing = async (page: number) => {
+    const result = await getActorFollowing(actor.handle, page, token).catch(() => null);
+    if (!result) return;
+    setFollowing((prev) => (page === 1 ? result.items : [...prev, ...result.items]));
+    setFollowingHasMore(result.hasMore);
+    setFollowingLoaded(true);
+    setFollowingPage(page);
+  };
+
+  const handleTabChange = (tab: string) => {
+    setActiveTab(tab as ConnectionTab);
+    if (tab === "followers" && !followersLoaded) loadFollowers(1);
+    if (tab === "following" && !followingLoaded) loadFollowing(1);
+  };
+
   const isOwnProfile = me?.username === actor.handle;
 
   const authorDetails = new Map<string, { avatarUrl?: string | null }>();
@@ -133,31 +170,6 @@ export function RemoteUserProfile({
                 </Link>
               </Button>
 
-              {(actor.followersUrl || actor.followingUrl) && (
-                <div className="mt-3 flex gap-3 text-sm">
-                  {actor.followersUrl && (
-                    <Link
-                      href={actor.followersUrl}
-                      target="_blank"
-                      rel="noopener noreferrer"
-                      className="text-muted-foreground hover:text-foreground hover:underline"
-                    >
-                      Followers
-                    </Link>
-                  )}
-                  {actor.followingUrl && (
-                    <Link
-                      href={actor.followingUrl}
-                      target="_blank"
-                      rel="noopener noreferrer"
-                      className="text-muted-foreground hover:text-foreground hover:underline"
-                    >
-                      Following
-                    </Link>
-                  )}
-                </div>
-              )}
-
               {actor.alsoKnownAs && (
                 <p className="mt-2 text-xs text-muted-foreground">
                   Also known as:{" "}
@@ -194,20 +206,86 @@ export function RemoteUserProfile({
           </div>
         </aside>
 
-        <div className="col-span-1 lg:col-span-3 space-y-4">
-          {initialPosts.length > 0 ? (
-            <ThoughtList
-              thoughts={initialPosts}
-              authorDetails={authorDetails}
-              currentUser={me}
-            />
-          ) : (
-            <Card className="flex items-center justify-center h-48">
-              <p className="text-center text-muted-foreground">
-                Posts are being fetched — check back soon.
-              </p>
-            </Card>
-          )}
+        <div className="col-span-1 lg:col-span-3">
+          <Tabs defaultValue="posts" onValueChange={handleTabChange}>
+            <TabsList>
+              <TabsTrigger value="posts">Posts</TabsTrigger>
+              <TabsTrigger value="followers">Followers</TabsTrigger>
+              <TabsTrigger value="following">Following</TabsTrigger>
+            </TabsList>
+
+            <TabsContent value="posts" className="space-y-4 mt-4">
+              {initialPosts.length > 0 ? (
+                <ThoughtList
+                  thoughts={initialPosts}
+                  authorDetails={authorDetails}
+                  currentUser={me}
+                />
+              ) : (
+                <Card className="flex items-center justify-center h-48">
+                  <p className="text-center text-muted-foreground">
+                    Posts are being fetched — check back soon.
+                  </p>
+                </Card>
+              )}
+            </TabsContent>
+
+            <TabsContent value="followers" className="mt-4">
+              {!followersLoaded ? (
+                <Card className="flex items-center justify-center h-48">
+                  <p className="text-center text-muted-foreground">Loading followers…</p>
+                </Card>
+              ) : followers.length === 0 ? (
+                <Card className="flex items-center justify-center h-48">
+                  <p className="text-center text-muted-foreground">
+                    No followers cached yet — check back soon.
+                  </p>
+                </Card>
+              ) : (
+                <div className="space-y-2">
+                  {followers.map((f) => (
+                    <RemoteUserCard key={f.url} actor={f} />
+                  ))}
+                  {followersHasMore && (
+                    <button
+                      onClick={() => loadFollowers(followersPage + 1)}
+                      className="w-full text-sm text-muted-foreground hover:text-foreground py-2"
+                    >
+                      Load more
+                    </button>
+                  )}
+                </div>
+              )}
+            </TabsContent>
+
+            <TabsContent value="following" className="mt-4">
+              {!followingLoaded ? (
+                <Card className="flex items-center justify-center h-48">
+                  <p className="text-center text-muted-foreground">Loading following…</p>
+                </Card>
+              ) : following.length === 0 ? (
+                <Card className="flex items-center justify-center h-48">
+                  <p className="text-center text-muted-foreground">
+                    No following cached yet — check back soon.
+                  </p>
+                </Card>
+              ) : (
+                <div className="space-y-2">
+                  {following.map((f) => (
+                    <RemoteUserCard key={f.url} actor={f} />
+                  ))}
+                  {followingHasMore && (
+                    <button
+                      onClick={() => loadFollowing(followingPage + 1)}
+                      className="w-full text-sm text-muted-foreground hover:text-foreground py-2"
+                    >
+                      Load more
+                    </button>
+                  )}
+                </div>
+              )}
+            </TabsContent>
+          </Tabs>
         </div>
       </main>
     </div>

thoughts-frontend/lib/api.ts

@@ -270,6 +270,44 @@ export const getRemoteActorPosts = (
     token
   );
 
+export const ActorConnectionSchema = z.object({
+  handle: z.string(),
+  displayName: z.string().nullable(),
+  avatarUrl: z.string().nullable(),
+  url: z.string(),
+});
+export type ActorConnection = z.infer<typeof ActorConnectionSchema>;
+
+const ActorConnectionPageSchema = z.object({
+  items: z.array(ActorConnectionSchema),
+  page: z.number(),
+  hasMore: z.boolean(),
+});
+
+export const getActorFollowers = (
+  handle: string,
+  page: number,
+  token: string | null
+) =>
+  apiFetch(
+    `/federation/actors/${encodeURIComponent(handle)}/followers-list?page=${page}`,
+    {},
+    ActorConnectionPageSchema,
+    token
+  );
+
+export const getActorFollowing = (
+  handle: string,
+  page: number,
+  token: string | null
+) =>
+  apiFetch(
+    `/federation/actors/${encodeURIComponent(handle)}/following-list?page=${page}`,
+    {},
+    ActorConnectionPageSchema,
+    token
+  );
+
 export const getAllUsers = (page: number = 1, pageSize: number = 20) =>
   apiFetch(
     `/users?page=${page}&per_page=${pageSize}`,