support handling CLOSED messages from relay client.

relay.go

@@ -300,6 +300,10 @@ func (r *Relay) Connect(ctx context.Context) error {
 				if subscription, ok := r.Subscriptions.Load(string(*env)); ok {
 					subscription.dispatchEose()
 				}
+			case *ClosedEnvelope:
+				if subscription, ok := r.Subscriptions.Load(string(env.SubscriptionID)); ok {
+					subscription.dispatchClosed(env.Reason)
+				}
 			case *CountEnvelope:
 				if subscription, ok := r.Subscriptions.Load(string(env.SubscriptionID)); ok && env.Count != nil && subscription.countResult != nil {
 					subscription.countResult <- *env.Count
@@ -478,6 +482,7 @@ func (r *Relay) PrepareSubscription(ctx context.Context, filters Filters, opts .
 		counter:           int(current),
 		Events:            make(chan *Event),
 		EndOfStoredEvents: make(chan struct{}),
+		ClosedReason:      make(chan string, 1),
 		Filters:           filters,
 	}
 

subscription.go

@@ -26,11 +26,15 @@ type Subscription struct {
 	// the EndOfStoredEvents channel gets closed when an EOSE comes for that subscription
 	EndOfStoredEvents chan struct{}
 
+	// the ClosedReason channel emits the reason when a CLOSED message is received
+	ClosedReason chan string
+
 	// Context will be .Done() when the subscription ends
 	Context context.Context
 
 	live   atomic.Bool
 	eosed  atomic.Bool
+	closed atomic.Bool
 	cancel context.CancelFunc
 
 	// this keeps track of the events we've received before the EOSE that we must dispatch before
@@ -107,6 +111,13 @@ func (sub *Subscription) dispatchEose() {
 	}
 }
 
+func (sub *Subscription) dispatchClosed(reason string) {
+	if sub.closed.CompareAndSwap(false, true) {
+		sub.ClosedReason <- reason
+		close(sub.ClosedReason)
+	}
+}
+
 // Unsub closes the subscription, sending "CLOSE" to relay as in NIP-01.
 // Unsub() also closes the channel sub.Events and makes a new one.
 func (sub *Subscription) Unsub() {

subscription_test.go

@@ -8,7 +8,7 @@ import (
 	"time"
 )
 
-const RELAY = "wss://nostr.mom"
+const RELAY = "wss://relay.nostr.bg"
 
 // test if we can fetch a couple of random events
 func TestSubscribe(t *testing.T) {