Return ["CLOSED"] on failing subscriptions

src/bussy/mod.rs

@@ -41,6 +41,8 @@ pub enum Command {
     PipelineResRelayMessageOk(/* client_id */ uuid::Uuid, nostr::RelayMessage),
     PipelineResStreamOutEvent(Box<nostr::Event>),
     PipelineResOk,
+    // Subscription Errors
+    ClientSubscriptionError(/* error message */ String),
     // Other
     Str(String),
     ServiceError(Error),

src/relay/ws.rs

@@ -31,6 +31,12 @@ pub async fn client_connection(ws: WebSocket, context: Context, client_addr: Opt
         tokio::select! {
             Ok(message) = subscriber.recv() => {
                 match message.content {
+                    crate::bussy::Command::ClientSubscriptionError(error_message) => {
+                        if let Some(sender) = &client.client_connection {
+                                    log::info!("[Relay] sending [\"CLOSED\"] event to client: {}", client.client_id);
+                                    if !sender.is_closed() {sender.send(Ok(Message::text(error_message))).unwrap()};
+                            }
+                    },
                     crate::bussy::Command::PipelineResRelayMessageOk(client_id, relay_message) => {
                         if client.client_id == client_id {
                             if let Some(sender) = &client.client_connection {
@@ -226,7 +232,30 @@ async fn handle_req(
     let subscription = Subscription::new(subscription_id.clone(), filters);
     let needs_historical_events = subscription.needs_historical_events();
 
-    client.subscribe(subscription.clone()).unwrap();
+    if let Err(subscription_error) = client.subscribe(subscription.clone()) {
+        log::error!(
+            "Error on handle_req. client IP: {:?}, message: {}",
+            client.ip(),
+            &subscription_error.message
+        );
+        let message = format!(
+            "[\"CLOSED\", \"{}\", \"{}\"]",
+            subscription_id, subscription_error.message
+        );
+
+        context
+            .pubsub
+            .publish(
+                channels::MSG_RELAY,
+                crate::bussy::Message {
+                    source: channels::MSG_RELAY,
+                    content: crate::bussy::Command::ClientSubscriptionError(message),
+                },
+            )
+            .await;
+
+        return;
+    };
 
     if needs_historical_events {
         context

src/utils/structs.rs

@@ -75,7 +75,9 @@ impl Client {
                 sub_id_len
             );
 
-            return Err(Error::bad_request("sub request is too long"));
+            return Err(Error::bad_request(
+                "error: subscription request is too long",
+            ));
         }
 
         if self.subscriptions.contains_key(&k) {
@@ -92,7 +94,9 @@ impl Client {
         }
 
         if self.subscriptions.len() >= self.max_subs {
-            return Err(Error::bad_request("max subs exceeded"));
+            return Err(Error::bad_request(
+                "error: max subscriptions limit is exceeded",
+            ));
         }
 
         // Insert subscription