feat(sync): add typed acknowledgement effect

req: sync/006

examples/kanban/src/main.rs

@@ -15,7 +15,7 @@ use hemx_axum::{
 use hemx_kanban_example::ui::board::{self as board};
 use hemx_kanban_example::ui::board_card as card_board;
 use hemx_kanban_example::ui::{self, board as board_ui};
-use hemx_sync::{Channel, PresenceScope, PresenceTracker, PresenceUpdate};
+use hemx_sync::{Channel, PresenceScope, PresenceTracker, PresenceUpdate, SyncEffect};
 use serde::{Deserialize, Serialize};
 use std::collections::BTreeMap;
 use std::convert::Infallible;
@@ -502,6 +502,7 @@ async fn main() {
         .route("/", get(home).post(interact))
         .route("/events", get(events))
         .route("/sync/broadcast", get(sync_broadcast))
+        .route("/sync/ack", get(sync_ack))
         .route("/sync-demo", get(sync_demo))
         .route("/sync.js", get(sync_js))
         .route("/sync/context", get(sync_context))
@@ -601,6 +602,39 @@ fn presence_changed(signal: PresenceSignal) -> impl hemx::IntoEffect {
     })
 }
 
+async fn sync_ack(
+    State(state): State<Arc<AppState>>,
+    headers: HeaderMap,
+    Query(params): Query<BTreeMap<String, String>>,
+) -> Result<Response, SyncRejection> {
+    let principal = current_sync_principal(&headers, &state.sync_sessions)?;
+    let command_id = CommandId::parse(params.get("command_id"))?;
+    let acknowledgement = {
+        let sync = state.sync.lock().unwrap();
+        let acknowledgement =
+            sync.acknowledgements
+                .get(&command_id)
+                .ok_or(SyncRejection::Conflict(
+                    "command has no canonical acknowledgement",
+                ))?;
+        if !visible_acknowledgement(principal, acknowledgement) {
+            return Err(SyncRejection::Forbidden(
+                "current tenant cannot access command acknowledgement",
+            ));
+        }
+        acknowledgement.clone()
+    };
+    let batch = (
+        SyncEffect::ack(board::atoms::sync_ack),
+        board::sync_status.text(format!(
+            "Canonical acknowledgement {} at server sequence {}",
+            acknowledgement.command_id, acknowledgement.server_sequence
+        )),
+    )
+        .into_batch(ui::BUILD_FINGERPRINT);
+    Ok(sse(stream::iter([Ok::<_, Infallible>(batch)]).boxed()).into_response())
+}
+
 async fn sync_broadcast(
     State(state): State<Arc<AppState>>,
     Query(params): Query<BTreeMap<String, String>>,