fix(notification): fix wrongly error report in notification (#70)

crates/rmcp/Cargo.toml

@@ -96,4 +96,10 @@ path = "tests/test_with_python.rs"
 [[test]]
 name = "test_with_js"
 required-features = ["server", "client", "transport-sse-server", "transport-child-process"]
-path = "tests/test_with_js.rs"
+path = "tests/test_with_js.rs"
+
+[[test]]
+name = "test_notification"
+required-features = ["server", "client"]
+path = "tests/test_notification.rs"
+

crates/rmcp/src/handler/server.rs

@@ -103,7 +103,7 @@ impl<H: ServerHandler> Service<RoleServer> for H {
 }
 
 #[allow(unused_variables)]
-pub trait ServerHandler: Sized + Clone + Send + Sync + 'static {
+pub trait ServerHandler: Sized + Send + Sync + 'static {
     fn ping(
         &self,
         context: RequestContext<RoleServer>,

crates/rmcp/src/service.rs

@@ -342,10 +342,12 @@ impl<R: ServiceRole> Peer<R> {
         self.tx
             .send(PeerSinkMessage::Notification(notification, responder))
             .await
-            .map_err(|_m| ServiceError::Transport(std::io::Error::other("disconnected")))?;
-        receiver
-            .await
-            .map_err(|_e| ServiceError::Transport(std::io::Error::other("disconnected")))?
+            .map_err(|_m| {
+                ServiceError::Transport(std::io::Error::other("disconnected: receiver dropped"))
+            })?;
+        receiver.await.map_err(|_e| {
+            ServiceError::Transport(std::io::Error::other("disconnected: responder dropped"))
+        })?
     }
     pub async fn send_request(&self, request: R::Req) -> Result<R::PeerResp, ServiceError> {
         self.send_cancellable_request(request, PeerRequestOptions::no_options())
@@ -578,10 +580,12 @@ where
                     let send_result = sink
                         .send(Message::Notification(notification).into_json_rpc_message())
                         .await;
-                    if let Err(e) = send_result {
-                        let _ =
-                            responder.send(Err(ServiceError::Transport(std::io::Error::other(e))));
-                    }
+                    let response = if let Err(e) = send_result {
+                        Err(ServiceError::Transport(std::io::Error::other(e)))
+                    } else {
+                        Ok(())
+                    };
+                    let _ = responder.send(response);
                     if let Some(param) = cancellation_param {
                         if let Some(responder) = local_responder_pool.remove(&param.request_id) {
                             tracing::info!(id = %param.request_id, reason = param.reason, "cancelled");

crates/rmcp/tests/test_notification.rs

@@ -0,0 +1,101 @@
+use std::sync::Arc;
+
+use rmcp::{
+    ClientHandler, Peer, RoleClient, ServerHandler, ServiceExt,
+    model::{
+        ResourceUpdatedNotificationParam, ServerCapabilities, ServerInfo, SubscribeRequestParam,
+    },
+};
+use tokio::sync::Notify;
+use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
+
+pub struct Server {}
+
+impl ServerHandler for Server {
+    fn get_info(&self) -> ServerInfo {
+        ServerInfo {
+            capabilities: ServerCapabilities::builder()
+                .enable_resources()
+                .enable_resources_subscribe()
+                .enable_resources_list_changed()
+                .build(),
+            ..Default::default()
+        }
+    }
+
+    async fn subscribe(
+        &self,
+        request: rmcp::model::SubscribeRequestParam,
+        context: rmcp::service::RequestContext<rmcp::RoleServer>,
+    ) -> Result<(), rmcp::Error> {
+        let uri = request.uri;
+        let peer = context.peer;
+
+        tokio::spawn(async move {
+            let span = tracing::info_span!("subscribe", uri = %uri);
+            let _enter = span.enter();
+
+            if let Err(e) = peer
+                .notify_resource_updated(ResourceUpdatedNotificationParam { uri: uri.clone() })
+                .await
+            {
+                panic!("Failed to send notification: {}", e);
+            }
+        });
+
+        Ok(())
+    }
+}
+
+pub struct Client {
+    receive_signal: Arc<Notify>,
+    peer: Option<Peer<RoleClient>>,
+}
+
+impl ClientHandler for Client {
+    async fn on_resource_updated(&self, params: rmcp::model::ResourceUpdatedNotificationParam) {
+        let uri = params.uri;
+        tracing::info!("Resource updated: {}", uri);
+        self.receive_signal.notify_one();
+    }
+
+    fn set_peer(&mut self, peer: Peer<RoleClient>) {
+        self.peer.replace(peer);
+    }
+
+    fn get_peer(&self) -> Option<Peer<RoleClient>> {
+        self.peer.clone()
+    }
+}
+
+#[tokio::test]
+async fn test_server_notification() -> anyhow::Result<()> {
+    let _ = tracing_subscriber::registry()
+        .with(
+            tracing_subscriber::EnvFilter::try_from_default_env()
+                .unwrap_or_else(|_| "debug".to_string().into()),
+        )
+        .with(tracing_subscriber::fmt::layer())
+        .try_init();
+    let (server_transport, client_transport) = tokio::io::duplex(4096);
+    tokio::spawn(async move {
+        let server = Server {}.serve(server_transport).await?;
+        server.waiting().await?;
+        anyhow::Ok(())
+    });
+    let receive_signal = Arc::new(Notify::new());
+    let client = Client {
+        peer: Default::default(),
+        receive_signal: receive_signal.clone(),
+    }
+    .serve(client_transport)
+    .await?;
+    client
+        .subscribe(SubscribeRequestParam {
+            uri: "test://test-resource".to_owned(),
+        })
+        .await?;
+    receive_signal.notified().await;
+    client.cancel().await?;
+    Ok(())
+}