feat: copy generic AP source files from thoughts

src/followers_handler.rs

@@ -0,0 +1,105 @@
+use activitypub_federation::{axum::json::FederationJson, config::Data};
+use axum::extract::{Path, Query};
+use serde::Deserialize;
+use serde_json::json;
+
+use crate::data::FederationData;
+use crate::error::Error;
+use crate::urls::AP_PAGE_SIZE;
+
+#[derive(Deserialize)]
+pub struct PageQuery {
+    page: Option<u32>,
+}
+
+async fn collection_handler(
+    user_id_str: &str,
+    query: PageQuery,
+    data: Data<FederationData>,
+    collection_type: &str,
+) -> Result<FederationJson<serde_json::Value>, Error> {
+    let user_id = uuid::Uuid::parse_str(user_id_str)
+        .map_err(|_| Error::bad_request(anyhow::anyhow!("invalid user id")))?;
+
+    data.user_repo
+        .find_by_id(user_id)
+        .await
+        .map_err(Error::from)?
+        .ok_or_else(|| Error::not_found(anyhow::anyhow!("user not found")))?;
+
+    let collection_id = format!(
+        "{}/users/{}/{}",
+        data.base_url, user_id_str, collection_type
+    );
+
+    let total = match collection_type {
+        "followers" => data.federation_repo.count_followers(user_id).await,
+        _ => data.federation_repo.count_following(user_id).await,
+    }
+    .map_err(Error::from)?;
+
+    if let Some(page) = query.page {
+        let page = page.max(1);
+        let offset = (page.saturating_sub(1) as usize) * AP_PAGE_SIZE;
+
+        let items: Vec<String> = match collection_type {
+            "followers" => data
+                .federation_repo
+                .get_followers_page(user_id, offset as u32, AP_PAGE_SIZE)
+                .await
+                .map_err(Error::from)?
+                .into_iter()
+                .map(|f| f.actor.url)
+                .collect(),
+            _ => data
+                .federation_repo
+                .get_following_page(user_id, offset as u32, AP_PAGE_SIZE)
+                .await
+                .map_err(Error::from)?
+                .into_iter()
+                .map(|a| a.url)
+                .collect(),
+        };
+
+        let has_next = offset + items.len() < total;
+
+        let mut obj = json!({
+            "@context": crate::urls::AP_CONTEXT,
+            "type": "OrderedCollectionPage",
+            "id": format!("{}?page={}", collection_id, page),
+            "partOf": collection_id,
+            "totalItems": total,
+            "orderedItems": items,
+        });
+
+        if has_next {
+            obj["next"] = json!(format!("{}?page={}", collection_id, page + 1));
+        }
+
+        Ok(FederationJson(obj))
+    } else {
+        Ok(FederationJson(json!({
+            "@context": crate::urls::AP_CONTEXT,
+            "type": "OrderedCollection",
+            "id": collection_id,
+            "totalItems": total,
+            "first": format!("{}?page=1", collection_id),
+        })))
+    }
+}
+
+pub async fn followers_handler(
+    Path(user_id_str): Path<String>,
+    Query(query): Query<PageQuery>,
+    data: Data<FederationData>,
+) -> Result<FederationJson<serde_json::Value>, Error> {
+    collection_handler(&user_id_str, query, data, "followers").await
+}
+
+pub async fn following_handler(
+    Path(user_id_str): Path<String>,
+    Query(query): Query<PageQuery>,
+    data: Data<FederationData>,
+) -> Result<FederationJson<serde_json::Value>, Error> {
+    collection_handler(&user_id_str, query, data, "following").await
+}