feat: signed actor lookup and display_name on DbActor

Add display_name field to DbActor, populated from AP Person.name in
from_json. Expose LookedUpActor type and lookup_actor_by_handle method
on ActivityPubService — uses the existing signed webfinger_https path
so strict instances (Threads, etc.) return full actor data.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "k-ap"
-version = "0.1.0"
+version = "0.1.4"
 edition = "2024"
 description = "Generic ActivityPub protocol layer"
 license = "MIT"

src/actors.rs

@@ -19,6 +19,7 @@ use crate::user::ApProfileField;
 pub struct DbActor {
     pub user_id: uuid::Uuid,
     pub username: String,
+    pub display_name: Option<String>,
     pub public_key_pem: String,
     pub private_key_pem: Option<String>,
     pub inbox_url: Url,
@@ -152,6 +153,7 @@ pub async fn get_local_actor(
     Ok(DbActor {
         user_id,
         username: user.username,
+        display_name: None,
         public_key_pem: public_key,
         private_key_pem: Some(private_key),
         inbox_url,
@@ -219,6 +221,7 @@ impl Object for DbActor {
         Ok(Some(DbActor {
             user_id,
             username: user.username,
+            display_name: None,
             public_key_pem: public_key,
             private_key_pem: private_key,
             inbox_url,
@@ -327,6 +330,7 @@ impl Object for DbActor {
         Ok(DbActor {
             user_id,
             username: json.preferred_username.clone(),
+            display_name: json.name.clone(),
             public_key_pem: json.public_key.public_key_pem,
             private_key_pem: None,
             inbox_url,

src/lib.rs

@@ -25,4 +25,4 @@ pub use repository::{
     BlockedDomain, FederationRepository, Follower, FollowerStatus, FollowingStatus, RemoteActor,
 };
 pub use service::ActivityPubService;
-pub use user::{ApProfileField, ApUser, ApUserRepository};
+pub use user::{ApProfileField, ApUser, ApUserRepository, LookedUpActor};

src/service.rs

@@ -330,6 +330,33 @@ impl ActivityPubService {
         Ok(serde_json::to_string(&WithContext::new_default(person))?)
     }
 
+    /// Resolve a `@user@domain` handle to actor data using a signed HTTP request.
+    /// Unlike a plain unauthenticated fetch, this works with instances (e.g. Threads)
+    /// that require HTTP signatures before returning full actor JSON.
+    pub async fn lookup_actor_by_handle(
+        &self,
+        handle: &str,
+    ) -> anyhow::Result<crate::user::LookedUpActor> {
+        let data = self.federation_config.to_request_data();
+        let actor = Self::webfinger_https(handle, &data).await?;
+        let domain = actor.ap_id.host_str().unwrap_or("").to_string();
+        let handle = format!("{}@{}", actor.username, domain);
+        Ok(crate::user::LookedUpActor {
+            handle,
+            display_name: actor.display_name,
+            bio: actor.bio,
+            avatar_url: actor.avatar_url,
+            banner_url: actor.banner_url,
+            ap_url: actor.ap_id,
+            outbox_url: actor.outbox_url,
+            followers_url: actor.followers_url,
+            following_url: actor.following_url,
+            also_known_as: actor.also_known_as,
+            profile_url: actor.profile_url,
+            attachment: actor.attachment,
+        })
+    }
+
     /// Returns the ActivityPub router compatible with any outer state `S`.
     /// Handlers only use `Data<FederationData>` injected by the middleware layer,
     /// so the router is independent of the application state type.

src/user.rs

@@ -7,6 +7,24 @@ pub struct ApProfileField {
     pub value: String,
 }
 
+/// Resolved actor data returned by [`crate::service::ActivityPubService::lookup_actor_by_handle`].
+/// Fetched via a signed HTTP request so strict instances (e.g. Threads) return full data.
+#[derive(Debug, Clone)]
+pub struct LookedUpActor {
+    pub handle: String,
+    pub display_name: Option<String>,
+    pub bio: Option<String>,
+    pub avatar_url: Option<Url>,
+    pub banner_url: Option<Url>,
+    pub ap_url: Url,
+    pub outbox_url: Url,
+    pub followers_url: Url,
+    pub following_url: Url,
+    pub also_known_as: Option<String>,
+    pub profile_url: Option<Url>,
+    pub attachment: Vec<ApProfileField>,
+}
+
 #[derive(Debug, Clone)]
 pub struct ApUser {
     pub id: uuid::Uuid,