implement trickle ice

cmd/demo-signal-client/main.go

@@ -266,6 +266,8 @@ func (client *SignalClient) HandleConnection(ctx context.Context, grpcClient *gr
 			client.OnOffer(ctx, stream, room, msg.Sender, inner.SessionOffer.SDP)
 		case *proto.SignalingMessage_SessionAnswer:
 			client.OnAnswer(ctx, msg.Sender, inner.SessionAnswer.SDP)
+		case *proto.SignalingMessage_ICECandidate:
+			client.OnIceCandidate(ctx, msg.Sender, inner.ICECandidate.Candidate)
 		}
 	}
 }
@@ -298,6 +300,27 @@ func (client *SignalClient) OnDiscoverResponse(ctx context.Context, stream proto
 	if err != nil {
 		return
 	}
+
+	peerConnection.OnICECandidate(func(i *webrtc.ICECandidate) {
+		if i == nil {
+			return
+		}
+		buffer := &bytes.Buffer{}
+		if err := json.NewEncoder(buffer).Encode(i.ToJSON()); err != nil {
+			return
+		}
+		stream.Send(&proto.SignalingMessage{
+			Room:     client.Room,
+			Sender:   client.Name,
+			Receiver: &sender,
+			Message: &proto.SignalingMessage_ICECandidate{
+				ICECandidate: &proto.ICECandidate{
+					Candidate: buffer.String(),
+					Sender:    client.Name,
+				},
+			},
+		})
+	})
 	dataChannel, err := peerConnection.CreateDataChannel(dataChannelName, nil)
 	if err != nil {
 		client.Program.Send(systemMsg(fmt.Sprint("failed to create answer: ", err)))
@@ -314,8 +337,10 @@ func (client *SignalClient) OnDiscoverResponse(ctx context.Context, stream proto
 	}
 	peerConnection.SetLocalDescription(sdp)
 
+	if !trickleIce {
 		gatherComplete := webrtc.GatheringCompletePromise(peerConnection)
 		<-gatherComplete
+	}
 
 	buffer := &bytes.Buffer{}
 	if err := json.NewEncoder(buffer).Encode(peerConnection.LocalDescription()); err != nil {
@@ -347,6 +372,26 @@ func (client *SignalClient) OnOffer(ctx context.Context, stream proto.Signaling_
 	if err != nil {
 		return
 	}
+	peerConnection.OnICECandidate(func(i *webrtc.ICECandidate) {
+		if i == nil {
+			return
+		}
+		buffer := &bytes.Buffer{}
+		if err := json.NewEncoder(buffer).Encode(i.ToJSON()); err != nil {
+			return
+		}
+		stream.Send(&proto.SignalingMessage{
+			Room:     client.Room,
+			Sender:   client.Name,
+			Receiver: &sender,
+			Message: &proto.SignalingMessage_ICECandidate{
+				ICECandidate: &proto.ICECandidate{
+					Candidate: buffer.String(),
+					Sender:    client.Name,
+				},
+			},
+		})
+	})
 	var offer webrtc.SessionDescription
 	if err := json.NewDecoder(strings.NewReader(sdp)).Decode(&offer); err != nil {
 		client.Program.Send(systemMsg(fmt.Sprint("Failed to decode offer for peer"+sender+": ", err)))
@@ -361,8 +406,10 @@ func (client *SignalClient) OnOffer(ctx context.Context, stream proto.Signaling_
 	}
 	peerConnection.SetLocalDescription(answer)
 
+	if !trickleIce {
 		gatherComplete := webrtc.GatheringCompletePromise(peerConnection)
 		<-gatherComplete
+	}
 
 	buffer := &bytes.Buffer{}
 	if err := json.NewEncoder(buffer).Encode(peerConnection.LocalDescription()); err != nil {
@@ -400,6 +447,20 @@ func (client *SignalClient) OnAnswer(ctx context.Context, sender, sdp string) {
 
 }
 
+func (client SignalClient) OnIceCandidate(ctx context.Context, sender, candidate string) {
+	peerConnection, ok := client.PeerConns[sender]
+	if !ok {
+		return
+	}
+	candidateInit := webrtc.ICECandidateInit{}
+	if err := json.NewDecoder(strings.NewReader(candidate)).Decode(&candidateInit); err != nil {
+		return
+	}
+
+	client.Program.Send(systemMsg("Client " + sender + " has offered candidate: " + candidateInit.Candidate))
+	peerConnection.AddICECandidate(candidateInit)
+}
+
 func (client SignalClient) GetOrCreatePeerConnection(sender string) (*webrtc.PeerConnection, error) {
 	client.Lock.Lock()
 	defer client.Lock.Unlock()
@@ -469,6 +530,7 @@ var (
 	serverUrl  string
 	serverRoom string
 	iceServers []string
+	trickleIce bool
 
 	cmd = &cobra.Command{
 		Run: func(cmd *cobra.Command, args []string) {
@@ -488,6 +550,7 @@ func main() {
 	cmd.Flags().StringVar(&serverUrl, "server", "https://chat.jeffthecoder.xyz", "")
 	cmd.Flags().StringVar(&serverRoom, "room", "public", "")
 	cmd.Flags().StringSliceVar(&iceServers, "ice-servers", []string{"stun:nhz.jeffthecoder.xyz:3478", "stun:nhz.jeffthecoder.xyz:3479"}, "")
+	cmd.Flags().BoolVar(&trickleIce, "trickle-ice", false, "")
 
 	cmd.Execute()
 }

pkg/impl/signal-server/signaling.go

@@ -96,6 +96,16 @@ func (signalingServer SignalingServer) handleStream(ctx context.Context, name st
 					} else {
 						log.Printf("peers received session answer: %v", received)
 					}
+				case *proto.SignalingMessage_ICECandidate:
+					payload := &bytes.Buffer{}
+					if err := json.NewEncoder(payload).Encode(innerMsg.ICECandidate); err != nil {
+						return err
+					}
+					if received, err := signalingServer.redis.Publish(ctx, signalingServer.redisKeyPrefix+":"+msg.Room+":icecandidate:"+*msg.Receiver, payload.String()).Result(); err != nil {
+						return err
+					} else {
+						log.Printf("peers received candidate: %v: %s", received, innerMsg.ICECandidate.Candidate)
+					}
 				}
 			} else {
 				return err
@@ -111,6 +121,7 @@ func (signalingServer SignalingServer) handleRedisPubSub(ctx context.Context, na
 			signalingServer.redisKeyPrefix+":"+room+":discover:"+name,
 			signalingServer.redisKeyPrefix+":"+room+":offer:"+name,
 			signalingServer.redisKeyPrefix+":"+room+":answer:"+name,
+			signalingServer.redisKeyPrefix+":"+room+":icecandidate:"+name,
 		)
 		defer pubsub.Unsubscribe(ctx)
 		defer pubsub.Close()
@@ -183,6 +194,21 @@ func (signalingServer SignalingServer) handleRedisPubSub(ctx context.Context, na
 					}); err != nil {
 						return err
 					}
+				case signalingServer.redisKeyPrefix + ":" + room + ":icecandidate:" + name:
+					candidate := &proto.ICECandidate{}
+					if err := json.NewDecoder(strings.NewReader(msg.Payload)).Decode(candidate); err != nil {
+						return err
+					}
+					if err := stream.Send(&proto.SignalingMessage{
+						Room:     room,
+						Sender:   candidate.Sender,
+						Receiver: &name,
+						Message: &proto.SignalingMessage_ICECandidate{
+							ICECandidate: candidate,
+						},
+					}); err != nil {
+						return err
+					}
 				}
 			}
 		}

pkg/proto/signaling/signaling.proto

@@ -19,6 +19,11 @@ message SDPMessage {
   string Sender = 3;
 }
 
+message ICECandidate {
+  string Candidate = 1;
+  string Sender = 2;
+}
+
 message SignalingMessage {
   string Room = 1;
   string Sender = 2;
@@ -30,6 +35,7 @@ message SignalingMessage {
 
     SDPMessage SessionOffer = 13;
     SDPMessage SessionAnswer = 14;
+    ICECandidate ICECandidate = 15;
   };
 }