prevent relay queriers that exit before EOSE from locking the QueryEvents() function forever.

badger/query.go

@@ -127,7 +127,11 @@ func (b BadgerBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (ch
 		for {
 			// emit latest event in queue
 			latest := emitQueue[0]
-			ch <- latest.Event
+			select {
+			case ch <- latest.Event:
+			case <-ctx.Done():
+				return
+			}
 
 			// stop when reaching limit
 			emittedEvents++

bolt/query.go

@@ -114,7 +114,11 @@ func (b *BoltBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (cha
 		for {
 			// emit latest event in queue
 			latest := emitQueue[0]
-			ch <- latest.Event
+			select {
+			case ch <- latest.Event:
+			case <-ctx.Done():
+				return
+			}
 
 			// stop when reaching limit
 			emittedEvents++

elasticsearch/query.go

@@ -123,9 +123,15 @@ func (ess *ElasticsearchStorage) QueryEvents(ctx context.Context, filter nostr.F
 	// optimization: get by id
 	if isGetByID(filter) {
 		if evts, err := ess.getByID(filter); err == nil {
-			for _, evt := range evts {
-				ch <- evt
-			}
+			go func() {
+				for _, evt := range evts {
+					select {
+					case ch <- evt:
+					case <-ctx.Done():
+						return
+					}
+				}
+			}()
 			close(ch)
 		} else {
 			return nil, fmt.Errorf("error getting by id: %w", err)

lmdb/query.go

@@ -146,7 +146,11 @@ func (b *LMDBBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (cha
 		for {
 			// emit latest event in queue
 			latest := emitQueue[0]
-			ch <- latest.Event
+			select {
+			case ch <- latest.Event:
+			case <-ctx.Done():
+				return
+			}
 
 			// stop when reaching limit
 			emittedEvents++

mysql/query.go

@@ -37,7 +37,11 @@ func (b MySQLBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (ch
 				return
 			}
 			evt.CreatedAt = nostr.Timestamp(timestamp)
-			ch <- &evt
+			select {
+			case ch <- &evt:
+			case <-ctx.Done():
+				return
+			}
 		}
 	}()
 

postgresql/query.go

@@ -34,7 +34,11 @@ func (b PostgresBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (
 				return
 			}
 			evt.CreatedAt = nostr.Timestamp(timestamp)
-			ch <- &evt
+			select {
+			case ch <- &evt:
+			case <-ctx.Done():
+				return
+			}
 		}
 	}()
 

slicestore/lib.go

@@ -55,7 +55,11 @@ func (b *SliceStore) QueryEvents(ctx context.Context, filter nostr.Filter) (chan
 				break
 			}
 			if filter.Matches(event) {
-				ch <- event
+				select {
+				case ch <- event:
+				case <-ctx.Done():
+					return
+				}
 				count++
 			}
 		}

sqlite3/query.go

@@ -34,7 +34,11 @@ func (b SQLite3Backend) QueryEvents(ctx context.Context, filter nostr.Filter) (c
 				return
 			}
 			evt.CreatedAt = nostr.Timestamp(timestamp)
-			ch <- &evt
+			select {
+			case ch <- &evt:
+			case <-ctx.Done():
+				return
+			}
 		}
 	}()