Support setting attributes from local participant (#470)

@@ -718,6 +718,19 @@ internal constructor(
         this.engine.client.sendUpdateLocalMetadata(metadata, name)
     }
 
+    /**
+     * Set or update participant attributes. It will make updates only to keys that
+     * are present in [attributes], and will not override others.
+     *
+     * To delete a value, set the value to an empty string.
+     *
+     * Note: this requires `canUpdateOwnMetadata` permission.
+     * @param attributes attributes to update
+     */
+    fun updateAttributes(attributes: Map<String, String>) {
+        this.engine.client.sendUpdateLocalMetadata(metadata, name, attributes)
+    }
+
     internal fun onRemoteMuteChanged(trackSid: String, muted: Boolean) {
         val pub = trackPublications[trackSid]
         pub?.muted = muted

@@ -62,6 +62,7 @@ object TestData {
             .setHidden(true)
             .setRecorder(false)
             .build()
+        putAttributes("attribute", "value")
         build()
     }
 
@@ -79,6 +80,7 @@ object TestData {
         }
         addTracks(REMOTE_AUDIO_TRACK)
         addTracks(REMOTE_VIDEO_TRACK)
+        putAttributes("attribute", "value")
         build()
     }
 
@@ -225,6 +227,7 @@ object TestData {
             val participantMetadataChanged = LOCAL_PARTICIPANT.toBuilder()
                 .setMetadata("changed_metadata")
                 .setName("changed_name")
+                .putAttributes("attribute", "changed_value")
                 .build()
 
             addParticipants(participantMetadataChanged)

@@ -152,6 +152,23 @@ class LocalParticipantMockE2ETest : MockE2ETest() {
     }
 
     @Test
+    fun updateAttributes() = runTest {
+        connect()
+        wsFactory.ws.clearRequests()
+
+        val newAttributes = mapOf("attribute" to "changedValue")
+        room.localParticipant.updateAttributes(newAttributes)
+
+        val requestString = wsFactory.ws.sentRequests.first().toPBByteString()
+        val sentRequest = LivekitRtc.SignalRequest.newBuilder()
+            .mergeFrom(requestString)
+            .build()
+
+        assertTrue(sentRequest.hasUpdateMetadata())
+        assertEquals(newAttributes, sentRequest.updateMetadata.attributesMap)
+    }
+
+    @Test
     fun participantMetadataChanged() = runTest {
         connect()
 
@@ -183,6 +200,7 @@ class LocalParticipantMockE2ETest : MockE2ETest() {
             listOf(
                 ParticipantEvent.MetadataChanged::class.java,
                 ParticipantEvent.NameChanged::class.java,
+                ParticipantEvent.AttributesChanged::class.java,
             ),
             participantEvents,
         )