feat: improved NOTICE messages for events and subscriptions

src/conn.rs

@@ -1,7 +1,9 @@
 //! Client connection state
 use crate::close::Close;
+use crate::error::Error;
 use crate::error::Result;
 use crate::event::Event;
+
 use crate::subscription::Subscription;
 use log::*;
 use std::collections::HashMap;
@@ -33,7 +35,7 @@ impl ClientConn {
         ClientConn {
             client_id,
             subscriptions: HashMap::new(),
-            max_subs: 128,
+            max_subs: 32,
         }
     }
 
@@ -65,7 +67,7 @@ impl ClientConn {
                 "ignoring sub request with excessive length: ({})",
                 sub_id_len
             );
-            return Ok(());
+            return Err(Error::SubIdMaxLengthError);
         }
         // check if an existing subscription exists, and replace if so
         if self.subscriptions.contains_key(&k) {
@@ -77,9 +79,7 @@ impl ClientConn {
 
         // check if there is room for another subscription.
         if self.subscriptions.len() >= self.max_subs {
-            // TODO: return error/notice for this
-            info!("client has reached the maximum number of unique subscriptions");
-            return Ok(());
+            return Err(Error::SubMaxExceededError);
         }
         // add subscription
         self.subscriptions.insert(k, s);

src/error.rs

@@ -21,6 +21,10 @@ pub enum Error {
     CloseParseFailed,
     #[error("Event validation failed")]
     EventInvalid,
+    #[error("Subscription identifier max length exceeded")]
+    SubIdMaxLengthError,
+    #[error("Maximum concurrent subscription count reached")]
+    SubMaxExceededError,
     // this should be used if the JSON is invalid
     #[error("JSON parsing failed")]
     JsonParseFailed(serde_json::Error),

src/main.rs

@@ -156,7 +156,10 @@ async fn nostr_server(
                                 event_tx.send(e.clone()).await.ok();
                                 client_published_event_count += 1;
                             },
-                            Err(_) => {info!("client {} sent an invalid event", cid)}
+                            Err(_) => {
+                                info!("client {} sent an invalid event", cid);
+                                nostr_stream.send(NoticeRes("event was invalid".to_owned())).await.ok();
+                            }
                         }
                     },
                     Some(Ok(SubMsg(s))) => {
@@ -166,11 +169,18 @@ async fn nostr_server(
                         // * making a channel to cancel to request later
                         // * sending a request for a SQL query
                         let (abandon_query_tx, abandon_query_rx) = oneshot::channel::<()>();
-                        running_queries.insert(s.id.to_owned(), abandon_query_tx);
-                        // register this connection
-                        conn.subscribe(s.clone()).ok();
-                        // start a database query
-                        db::db_query(s, query_tx.clone(), abandon_query_rx).await;
+                        match conn.subscribe(s.clone()) {
+                            Ok(()) => {
+                                running_queries.insert(s.id.to_owned(), abandon_query_tx);
+                                // start a database query
+                                db::db_query(s, query_tx.clone(), abandon_query_rx).await;
+                            },
+                            Err(e) => {
+                                info!("Subscription error: {}", e);
+                                nostr_stream.send(NoticeRes(format!("{}",e))).await.ok();
+
+                            }
+                        }
                     },
                     Some(Ok(CloseMsg(cc))) => {
                         // closing a request simply removes the subscription.
@@ -187,7 +197,10 @@ async fn nostr_server(
                                 // the subscription
                                 conn.unsubscribe(c);
                             },
-                            Err(_) => {info!("invalid command ignored");}
+                            Err(_) => {
+                                info!("invalid command ignored");
+
+                            }
                         }
                     },
                     None => {