allow more fine-grained control over subscription filters.

relay.go

@@ -125,7 +125,7 @@ func (r *Relay) Connect() error {
 					}
 
 					// check if the event matches the desired filter, ignore otherwise
-					if !subscription.filters.Match(&event) {
+					if !subscription.Filters.Match(&event) {
 						continue
 					}
 
@@ -212,24 +212,30 @@ func (r *Relay) Subscribe(filters Filters) *Subscription {
 		panic(fmt.Errorf("must call .Connect() first before calling .Subscribe()"))
 	}
 
+	sub := r.PrepareSubscription()
+	sub.Filters = filters
+	sub.Fire()
+	return sub
+}
+
+func (r *Relay) PrepareSubscription() *Subscription {
 	random := make([]byte, 7)
 	rand.Read(random)
 	id := hex.EncodeToString(random)
-	return r.subscribe(id, filters)
+
+	return r.prepareSubscription(id)
 }
 
-func (r *Relay) subscribe(id string, filters Filters) *Subscription {
-	sub := Subscription{
+func (r *Relay) prepareSubscription(id string) *Subscription {
+	sub := &Subscription{
 		conn:              r.Connection,
 		id:                id,
 		Events:            make(chan Event),
 		EndOfStoredEvents: make(chan struct{}, 1),
 	}
 
-	r.subscriptions.Store(sub.id, &sub)
-
-	sub.Sub(filters)
-	return &sub
+	r.subscriptions.Store(sub.id, sub)
+	return sub
 }
 
 func (r *Relay) Close() error {

relaypool.go

@@ -78,7 +78,8 @@ func (r *RelayPool) Add(url string, policy RelayPoolPolicy) chan error {
 		r.Relays.Store(relay.URL, relay)
 
 		r.subscriptions.Range(func(id string, filters Filters) bool {
-			sub := relay.subscribe(id, filters)
+			sub := relay.prepareSubscription(id)
+			sub.Sub(filters)
 			eventStream, _ := r.eventStreams.Load(id)
 
 			go func(sub *Subscription) {
@@ -119,7 +120,8 @@ func (r *RelayPool) Sub(filters Filters) (string, chan EventMessage) {
 	r.eventStreams.Store(id, eventStream)
 
 	r.Relays.Range(func(_ string, relay *Relay) bool {
-		sub := relay.subscribe(id, filters)
+		sub := relay.prepareSubscription(id)
+		sub.Sub(filters)
 
 		go func(sub *Subscription) {
 			for evt := range sub.Events {

subscription.go

@@ -6,7 +6,7 @@ type Subscription struct {
 	id   string
 	conn *Connection
 
-	filters           Filters
+	Filters           Filters
 	Events            chan Event
 	EndOfStoredEvents chan struct{}
 
@@ -19,10 +19,6 @@ type EventMessage struct {
 	Relay string
 }
 
-func (sub Subscription) GetFilters() Filters {
-	return sub.filters
-}
-
 func (sub Subscription) Unsub() {
 	sub.conn.WriteJSON([]interface{}{"CLOSE", sub.id})
 
@@ -33,10 +29,13 @@ func (sub Subscription) Unsub() {
 }
 
 func (sub *Subscription) Sub(filters Filters) {
-	sub.filters = filters
+	sub.Filters = filters
+	sub.Fire()
+}
 
+func (sub *Subscription) Fire() {
 	message := []interface{}{"REQ", sub.id}
-	for _, filter := range sub.filters {
+	for _, filter := range sub.Filters {
 		message = append(message, filter)
 	}