Wildcard subscriptions

session/session.go

@@ -159,8 +159,10 @@ func (s *Session) VisitConnect(_ packets.ConnectPacket) {
 }
 
 func (s *Session) VisitPublish(p packets.PublishPacket) {
-	subs, lock := subscription.Subscriptions.GetSubscriptions(p.TopicName)
-	defer lock.Unlock()
+	subNodes := subscription.Subscriptions.GetSubscriptions(p.TopicName)
+	for _, subNode := range subNodes {
+		subNode.NodeLock.RLock()
+		defer subNode.NodeLock.RUnlock()
 		if p.QOSLevel == 0 {
 			if p.PacketId != nil {
 				log.Printf("Client: %v, Got publish with qos 0 and a packet id, ignoring\n", s.ClientID)
@@ -168,9 +170,6 @@ func (s *Session) VisitPublish(p packets.PublishPacket) {
 			}
 		} else if p.QOSLevel == 1 {
 			var reason packets.PubackReasonCode = packets.PubackReasonCodeSuccess
-		if len(subs) == 0 {
-			reason = packets.PubackReasonCodeNoMatchingSubscribers
-		}
 			ack := packets.PubackPacket{
 				PacketID: *p.PacketId,
 				Reason:   reason,
@@ -180,11 +179,12 @@ func (s *Session) VisitPublish(p packets.PublishPacket) {
 			panic("UNIMPLEMENTED QOS level 2")
 		}
 
-	for _, sub := range subs {
+		for _, sub := range subNode.Subscriptions {
 			if !(sub.NoLocal && sub.SubscriptionChannel == s.SubscriptionChannel) {
 				go func(sub subscription.Subscription) { sub.SubscriptionChannel <- p }(sub)
 			}
 		}
+	}
 }
 
 func (s *Session) VisitDisconnect(p packets.DisconnectPacket) {

subscription/subscription.go

@@ -19,9 +19,9 @@ type Subscription struct {
 }
 
 type SubscriptionTreeNode struct {
-	subscriptions []Subscription
 	children      map[string]*SubscriptionTreeNode
-	nodeLock      sync.RWMutex
+	Subscriptions []Subscription
+	NodeLock      sync.RWMutex
 }
 
 func newSubscriptionTreeNode() *SubscriptionTreeNode {
@@ -37,34 +37,36 @@ func (s *SubscriptionTreeNode) findNode(fields []string) *SubscriptionTreeNode {
 
 	field := fields[0]
 
-	s.nodeLock.RLock()
+	s.NodeLock.RLock()
 	_, exists := s.children[field]
 	// Insert a value into the map if one doesn't exist yet
 	if !exists {
 		// Can't upgrade a read lock so we need to unlock and
 		// check again, this time with a write lock
-		s.nodeLock.RUnlock()
-		s.nodeLock.Lock()
+		s.NodeLock.RUnlock()
+		s.NodeLock.Lock()
 
 		_, exists = s.children[field]
 		if !exists {
 			s.children[field] = newSubscriptionTreeNode()
 		}
-		s.nodeLock.Unlock()
-		s.nodeLock.RLock()
+		s.NodeLock.Unlock()
+		s.NodeLock.RLock()
 	}
 
 	child, _ := s.children[field]
-	s.nodeLock.RUnlock()
+	s.NodeLock.RUnlock()
 	return child.findNode(fields[1:])
 }
 
+
+
 func (s *SubscriptionTreeNode) removeSubscription(subChan SubscriptionChannel) {
-	for i, sub := range s.subscriptions {
+	for i, sub := range s.Subscriptions {
 		if sub.SubscriptionChannel == subChan {
-			lst := len(s.subscriptions) - 1
-			s.subscriptions[i] = s.subscriptions[lst]
-			s.subscriptions = s.subscriptions[:lst]
+			lst := len(s.Subscriptions) - 1
+			s.Subscriptions[i] = s.Subscriptions[lst]
+			s.Subscriptions = s.Subscriptions[:lst]
 		}
 	}
 }
@@ -73,34 +75,64 @@ func (s *SubscriptionTreeNode) Subscribe(topicFilter packets.TopicFilter, subCha
 	sub := Subscription{subChan, topicFilter}
 
 	node := s.findNode(topicFilter.Topic.Fields)
-	node.nodeLock.Lock()
-	node.subscriptions = append(node.subscriptions, sub)
-	node.nodeLock.Unlock()
+	node.NodeLock.Lock()
+	node.Subscriptions = append(node.Subscriptions, sub)
+	node.NodeLock.Unlock()
 }
 
 func (s *SubscriptionTreeNode) Unsubscribe(topic packets.Topic, subChan SubscriptionChannel) {
 	node := s.findNode(topic.Fields)
 
-	node.nodeLock.Lock()
+	node.NodeLock.Lock()
 	node.removeSubscription(subChan)
-	node.nodeLock.Unlock()
+	node.NodeLock.Unlock()
 }
 
 func (s *SubscriptionTreeNode) RemoveSubsForChannel(subChan SubscriptionChannel) {
 	for _, node := range s.children {
-		node.nodeLock.Lock()
+		node.NodeLock.Lock()
 		node.removeSubscription(subChan)
-		node.nodeLock.Unlock()
+		node.NodeLock.Unlock()
 
 		node.RemoveSubsForChannel(subChan)
 	}
 }
 
-func (s *SubscriptionTreeNode) GetSubscriptions(topicName string) ([]Subscription, sync.Locker) {
+// Returns the subscriptions whose filters match the given topic name
+func (s *SubscriptionTreeNode) GetSubscriptions(topicName string) []*SubscriptionTreeNode {
 	fields := strings.Split(topicName, "/")
-
-	child := s.findNode(fields)
-	locker := child.nodeLock.RLocker()
-	locker.Lock()
-	return child.subscriptions, locker
+	return s.matchSubscriptions(fields)
+}
+
+// Returns nodes with subscriptions that match the given topic 
+func (s *SubscriptionTreeNode) matchSubscriptions(fields []string) []*SubscriptionTreeNode {
+	if len(fields) == 0 {
+		return []*SubscriptionTreeNode{s}
+	}
+
+	sub := make([]*SubscriptionTreeNode, 0)
+
+	s.NodeLock.RLock()
+
+	// Single level wildcard(+)
+	if SlWildcard, exists := s.children["+"]; exists {
+		sub = append(sub, SlWildcard.matchSubscriptions(fields[1:])...)
+	}
+
+	// Multi level wildcard(#)
+	if MlWildcard, exists := s.children["#"]; exists {
+		sub = append(sub, MlWildcard)
+	}
+
+	field := fields[0]
+	if field == "#" || field == "+" {
+		// TODO handle gracefully
+		panic("Wildcard in topic")
+	}
+
+	if child, exists := s.children[field]; exists {
+		sub = append(sub, child.matchSubscriptions(fields[1:])...)
+	}
+	s.NodeLock.RUnlock()
+	return sub
 }

subscription/subscription_test.go

@@ -6,22 +6,52 @@ import (
 	"badat.dev/maeqtt/v2/mqtt/packets"
 )
 
-func TestSubscribe(t *testing.T) {
+func assertMatches(topic packets.Topic, topicName string, shouldMatch bool, t *testing.T) {
 	tree := newSubscriptionTreeNode()
-	topic, _ := packets.ParseTopic("a/b/c")
 	channel := make(SubscriptionChannel)
 	topicFilter := packets.TopicFilter{
 		Topic:  topic,
 		MaxQoS: 1,
 	}
 	tree.Subscribe(topicFilter, channel)
-	subs, lock := tree.GetSubscriptions("a/b/c")
-	defer lock.Unlock()
+	subs := tree.GetSubscriptions(topicName)
 
-	if len(subs) != 1 {
-		t.Errorf("Error storing subscriptions, expected to len(subs) to be 1, got: %v \n", len(subs))
+	if (len(subs) != 1) && shouldMatch {
+		t.Errorf("Topic %v did not match %v", topic, topicName)
 	}
-	if subs[0].MaxQoS != topicFilter.MaxQoS || subs[0].SubscriptionChannel != channel {
-		t.Error("Error with data stored in a subscription")
+	if (len(subs) == 1) && !shouldMatch {
+		t.Errorf("Topic %v matched %v (it wasn't supposed to)", topic, topicName )
 	}
 }
+
+func TestSubscribe(t *testing.T) {
+	topic, _ := packets.ParseTopic("a/b/c")
+	assertMatches(topic, "a/b/c", true, t)
+	assertMatches(topic, "a/c/c", false, t)
+	assertMatches(topic, "b/b/c", false, t)
+	assertMatches(topic, "aaa/c/a", false, t)
+}
+
+func TestSingleLevelWildcard(t *testing.T) {
+	topic, _ := packets.ParseTopic("a/+/c")
+	assertMatches(topic, "a/b/c", true, t)
+	assertMatches(topic, "a/c/c", true, t)
+	assertMatches(topic, "a/b/d", false, t)
+	assertMatches(topic, "aaa/c/a", false, t)
+
+	topic, _ = packets.ParseTopic("+/+/+")
+	assertMatches(topic, "a/b/c", true, t)
+	assertMatches(topic, "a/c/c", true, t)
+	assertMatches(topic, "a/b/d/e", false, t)
+	assertMatches(topic, "c/a", true, t)
+}
+
+func TestMultiLevelWildcard(t *testing.T) {
+	topic, _ := packets.ParseTopic("a/b/c/#")
+	assertMatches(topic, "a/b/c", true, t)
+	assertMatches(topic, "a/b/c/a", true, t)
+	assertMatches(topic, "a/b/c/d", true, t)
+	assertMatches(topic, "a/b/c/f", true, t)
+
+	assertMatches(topic, "a/b/d/a", false, t)
+}