Fix attribute update. Pass attribute diff instead of old state. (#496)

Author: dennwc

callback.go

@@ -20,12 +20,17 @@ import (
 	"github.com/livekit/protocol/livekit"
 )
 
+// ParticipantAttributesChangedFunc is callback for Participant attribute change event.
+// The function is called with an already updated participant state and the map of changes attributes.
+// Deleted attributes will have empty string value in the changed map.
+type ParticipantAttributesChangedFunc func(changed map[string]string, p Participant)
+
 type ParticipantCallback struct {
 	// for all participants
 	OnTrackMuted               func(pub TrackPublication, p Participant)
 	OnTrackUnmuted             func(pub TrackPublication, p Participant)
 	OnMetadataChanged          func(oldMetadata string, p Participant)
-	OnAttributesChanged        func(oldAttrs map[string]string, p Participant)
+	OnAttributesChanged        ParticipantAttributesChangedFunc
 	OnIsSpeakingChanged        func(p Participant)
 	OnConnectionQualityChanged func(update *livekit.ConnectionQualityInfo, p Participant)
 
@@ -44,7 +49,7 @@ func NewParticipantCallback() *ParticipantCallback {
 		OnTrackMuted:               func(pub TrackPublication, p Participant) {},
 		OnTrackUnmuted:             func(pub TrackPublication, p Participant) {},
 		OnMetadataChanged:          func(oldMetadata string, p Participant) {},
-		OnAttributesChanged:        func(oldAttrs map[string]string, p Participant) {},
+		OnAttributesChanged:        func(changed map[string]string, p Participant) {},
 		OnIsSpeakingChanged:        func(p Participant) {},
 		OnConnectionQualityChanged: func(update *livekit.ConnectionQualityInfo, p Participant) {},
 		OnTrackSubscribed:          func(track *webrtc.TrackRemote, publication *RemoteTrackPublication, rp *RemoteParticipant) {},

integration_test.go

@@ -47,7 +47,9 @@ var (
 
 func TestMain(m *testing.M) {
 	keys := strings.Split(os.Getenv("LIVEKIT_KEYS"), ": ")
-	apiKey, apiSecret = keys[0], keys[1]
+	if len(keys) >= 2 {
+		apiKey, apiSecret = keys[0], keys[1]
+	}
 
 	os.Exit(m.Run())
 }

participant.go

@@ -197,6 +197,21 @@ func (p *baseParticipant) setConnectionQualityInfo(info *livekit.ConnectionQuali
 	p.roomCallback.OnConnectionQualityChanged(info, p)
 }
 
+func attributeChanges(old, cur map[string]string) map[string]string {
+	diff := make(map[string]string)
+	for k, v := range cur {
+		if old[k] != v {
+			diff[k] = v // added or changed
+		}
+	}
+	for k := range old {
+		if _, ok := cur[k]; !ok {
+			diff[k] = "" // deleted
+		}
+	}
+	return diff
+}
+
 func (p *baseParticipant) updateInfo(pi *livekit.ParticipantInfo, participant Participant) bool {
 	p.lock.Lock()
 	if p.info != nil && p.info.Version > pi.Version {
@@ -211,27 +226,17 @@ func (p *baseParticipant) updateInfo(pi *livekit.ParticipantInfo, participant Pa
 	oldMetadata := p.metadata
 	p.metadata = pi.Metadata
 	metaChanged := oldMetadata != p.metadata
-	attrsChanged := len(pi.Attributes) != 0
-	oldAttributes := maps.Clone(p.attributes)
-	if p.attributes == nil {
-		p.attributes = make(map[string]string)
-	}
-	for k, v := range pi.Attributes {
-		if v == "" {
-			delete(p.attributes, k)
-		} else {
-			p.attributes[k] = v
-		}
-	}
+	attrsChanges := attributeChanges(p.attributes, pi.Attributes)
+	p.attributes = maps.Clone(pi.Attributes)
 	p.lock.Unlock()
 
 	if metaChanged {
 		p.Callback.OnMetadataChanged(oldMetadata, participant)
 		p.roomCallback.OnMetadataChanged(oldMetadata, participant)
 	}
-	if attrsChanged {
-		p.Callback.OnAttributesChanged(oldAttributes, participant)
-		p.roomCallback.OnAttributesChanged(oldAttributes, participant)
+	if len(attrsChanges) != 0 {
+		p.Callback.OnAttributesChanged(attrsChanges, participant)
+		p.roomCallback.OnAttributesChanged(attrsChanges, participant)
 	}
 	return true
 }

participant_test.go

@@ -0,0 +1,21 @@
+package lksdk
+
+import (
+	"github.com/stretchr/testify/require"
+	"testing"
+)
+
+func TestAttributeChanges(t *testing.T) {
+	diff := attributeChanges(map[string]string{
+		"a": "1",
+		"b": "2",
+	}, map[string]string{
+		"a": "2",
+		"c": "3",
+	})
+	require.Equal(t, map[string]string{
+		"a": "2",
+		"b": "",
+		"c": "3",
+	}, diff)
+}