WebRTC module refactoring

pkg/webrtc/server.go

@@ -0,0 +1,201 @@
+package webrtc
+
+import (
+	"github.com/AlexxIT/go2rtc/pkg/streamer"
+	"github.com/pion/sdp/v3"
+	"github.com/pion/webrtc/v3"
+)
+
+type Server struct {
+	streamer.Element
+
+	UserAgent string
+
+	conn *webrtc.PeerConnection
+
+	medias []*streamer.Media
+	tracks []*streamer.Track
+
+	receive int
+	send    int
+}
+
+func NewServer(conn *webrtc.PeerConnection) *Server {
+	c := &Server{conn: conn}
+
+	conn.OnICECandidate(func(candidate *webrtc.ICECandidate) {
+		c.Fire(candidate)
+	})
+
+	conn.OnTrack(func(remote *webrtc.TrackRemote, receiver *webrtc.RTPReceiver) {
+		for _, track := range c.tracks {
+			if track.Direction != streamer.DirectionRecvonly {
+				continue
+			}
+			if track.Codec.PayloadType != uint8(remote.PayloadType()) {
+				continue
+			}
+
+			for {
+				packet, _, err := remote.ReadRTP()
+				if err != nil {
+					return
+				}
+				if len(packet.Payload) == 0 {
+					continue
+				}
+				c.receive += len(packet.Payload)
+				_ = track.WriteRTP(packet)
+			}
+		}
+
+		//fmt.Printf("TODO: webrtc ontrack %+v\n", remote)
+	})
+
+	conn.OnDataChannel(func(channel *webrtc.DataChannel) {
+		c.Fire(channel)
+	})
+
+	// OK connection:
+	// 15:01:46 ICE connection state changed: checking
+	// 15:01:46 peer connection state changed: connected
+	// 15:01:54 peer connection state changed: disconnected
+	// 15:02:20 peer connection state changed: failed
+	//
+	// Fail connection:
+	// 14:53:08 ICE connection state changed: checking
+	// 14:53:39 peer connection state changed: failed
+	conn.OnConnectionStateChange(func(state webrtc.PeerConnectionState) {
+		c.Fire(state)
+
+		// TODO: remove
+		switch state {
+		case webrtc.PeerConnectionStateConnected:
+			c.Fire(streamer.StatePlaying) // TODO: remove
+		case webrtc.PeerConnectionStateDisconnected:
+			c.Fire(streamer.StateNull) // TODO: remove
+			// disconnect event comes earlier, than failed
+			// but it comes only for success connections
+			_ = conn.Close()
+		case webrtc.PeerConnectionStateFailed:
+			_ = conn.Close()
+		}
+	})
+
+	return c
+}
+
+func (c *Server) SetOffer(offer string) (err error) {
+	desc := webrtc.SessionDescription{
+		Type: webrtc.SDPTypeOffer, SDP: offer,
+	}
+	if err = c.conn.SetRemoteDescription(desc); err != nil {
+		return
+	}
+
+	rawSDP := []byte(c.conn.RemoteDescription().SDP)
+	sd := &sdp.SessionDescription{}
+	if err = sd.Unmarshal(rawSDP); err != nil {
+		return
+	}
+
+	medias := streamer.UnmarshalMedias(sd.MediaDescriptions)
+
+	// sort medias, so video will always be before audio
+	// and ignore application media from Hass default lovelace card
+	for _, media := range medias {
+		if media.Kind == streamer.KindVideo {
+			c.medias = append(c.medias, media)
+		}
+	}
+	for _, media := range medias {
+		if media.Kind == streamer.KindAudio {
+			c.medias = append(c.medias, media)
+		}
+	}
+
+	return
+}
+
+func (c *Server) GetAnswer() (answer string, err error) {
+	for _, tr := range c.conn.GetTransceivers() {
+		if tr.Direction() != webrtc.RTPTransceiverDirectionSendonly {
+			continue
+		}
+
+		// disable transceivers if we don't have track
+		// make direction=inactive
+		// don't really necessary, but anyway
+		if tr.Sender() == nil {
+			if err = tr.Stop(); err != nil {
+				return
+			}
+		}
+	}
+
+	var sdAnswer webrtc.SessionDescription
+	sdAnswer, err = c.conn.CreateAnswer(nil)
+	if err != nil {
+		return
+	}
+
+	if err = c.conn.SetLocalDescription(sdAnswer); err != nil {
+		return
+	}
+
+	return sdAnswer.SDP, nil
+}
+
+func (c *Server) GetCompleteAnswer() (answer string, err error) {
+	if _, err = c.GetAnswer(); err != nil {
+		return
+	}
+
+	<-webrtc.GatheringCompletePromise(c.conn)
+	return c.conn.LocalDescription().SDP, nil
+}
+
+func (c *Server) Close() error {
+	return c.conn.Close()
+}
+
+func (c *Server) AddCandidate(candidate string) {
+	// pion uses only candidate value from json/object candidate struct
+	_ = c.conn.AddICECandidate(webrtc.ICECandidateInit{Candidate: candidate})
+}
+
+func (c *Server) remote() string {
+	if c.conn == nil {
+		return ""
+	}
+
+	for _, trans := range c.conn.GetTransceivers() {
+		if trans == nil {
+			continue
+		}
+
+		receiver := trans.Receiver()
+		if receiver == nil {
+			continue
+		}
+
+		transport := receiver.Transport()
+		if transport == nil {
+			continue
+		}
+
+		iceTransport := transport.ICETransport()
+		if iceTransport == nil {
+			continue
+		}
+
+		pair, _ := iceTransport.GetSelectedCandidatePair()
+		if pair == nil || pair.Remote == nil {
+			continue
+		}
+
+		return pair.Remote.String()
+	}
+
+	return ""
+}