Big rewrite for WebRTC processing

cmd/webrtc/client.go

@@ -0,0 +1,154 @@
+package webrtc
+
+import (
+	"errors"
+	"github.com/AlexxIT/go2rtc/cmd/api"
+	"github.com/AlexxIT/go2rtc/pkg/streamer"
+	"github.com/AlexxIT/go2rtc/pkg/webrtc"
+	"github.com/gorilla/websocket"
+	pion "github.com/pion/webrtc/v3"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+func streamsHandler(url string) (streamer.Producer, error) {
+	url = url[7:]
+	if i := strings.Index(url, "://"); i > 0 {
+		switch url[:i] {
+		case "ws", "wss":
+			return asyncClient(url)
+		case "http", "https":
+			return syncClient(url)
+		}
+	}
+	return nil, errors.New("unsupported url: " + url)
+}
+
+func asyncClient(url string) (streamer.Producer, error) {
+	// 1. Connect to signalign server
+	ws, _, err := websocket.DefaultDialer.Dial(url, nil)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if err != nil {
+			_ = ws.Close()
+		}
+	}()
+
+	// 2. Create PeerConnection
+	pc, err := newPeerConnection()
+	if err != nil {
+		log.Error().Err(err).Caller().Send()
+		return nil, err
+	}
+
+	prod := webrtc.NewConn(pc)
+	prod.Listen(func(msg any) {
+		switch msg := msg.(type) {
+		case pion.PeerConnectionState:
+			_ = ws.Close()
+
+		case *pion.ICECandidate:
+			if msg != nil {
+				s := msg.ToJSON().Candidate
+				log.Trace().Str("candidate", s).Msg("[webrtc] local")
+				_ = ws.WriteJSON(&api.Message{Type: "webrtc/candidate", Value: s})
+			}
+		}
+	})
+
+	// 3. Create offer
+	offer, err := prod.CreateOffer()
+	if err != nil {
+		return nil, err
+	}
+
+	// 4. Send offer
+	msg := &api.Message{Type: "webrtc/offer", Value: offer}
+	if err = ws.WriteJSON(msg); err != nil {
+		return nil, err
+	}
+
+	// 5. Get answer
+	if err = ws.ReadJSON(msg); err != nil {
+		return nil, err
+	}
+
+	if msg.Type != "webrtc/answer" {
+		return nil, errors.New("wrong answer: " + msg.Type)
+	}
+
+	answer := msg.String()
+	if err = prod.SetAnswer(answer); err != nil {
+		return nil, err
+	}
+
+	// 6. Continue to receiving candidates
+	go func() {
+		for {
+			// receive data from remote
+			msg := new(api.Message)
+			if err = ws.ReadJSON(msg); err != nil {
+				if cerr, ok := err.(*websocket.CloseError); ok {
+					log.Trace().Err(err).Caller().Msgf("[webrtc] ws code=%d", cerr)
+				}
+				break
+			}
+
+			switch msg.Type {
+			case "webrtc/candidate":
+				if msg.Value != nil {
+					_ = prod.AddCandidate(msg.String())
+				}
+			}
+		}
+
+		_ = ws.Close()
+	}()
+
+	return prod, nil
+}
+
+// syncClient - support WebRTC-HTTP Egress Protocol (WHEP)
+func syncClient(url string) (streamer.Producer, error) {
+	// 2. Create PeerConnection
+	pc, err := newPeerConnection()
+	if err != nil {
+		log.Error().Err(err).Caller().Send()
+		return nil, err
+	}
+
+	prod := webrtc.NewConn(pc)
+
+	// 3. Create offer
+	offer, err := prod.CreateCompleteOffer()
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest("POST", url, strings.NewReader(offer))
+	req.Header.Set("Content-Type", MimeSDP)
+	if err != nil {
+		return nil, err
+	}
+
+	client := http.Client{Timeout: time.Second * 5000}
+	res, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+
+	answer, err := io.ReadAll(res.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if err = prod.SetAnswer(string(answer)); err != nil {
+		return nil, err
+	}
+
+	return prod, nil
+}