Big rewrite for WebRTC processing

2023-02-25 17:10:45 +03:00
parent ad3c5440fe
commit 218eea6806
10 changed files with 625 additions and 253 deletions
@@ -0,0 +1,196 @@
+package webrtc
+
+import (
+	"encoding/json"
+	"github.com/AlexxIT/go2rtc/cmd/streams"
+	"github.com/AlexxIT/go2rtc/pkg/webrtc"
+	pion "github.com/pion/webrtc/v3"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const MimeSDP = "application/sdp"
+
+var sessions = map[string]*webrtc.Conn{}
+
+func syncHandler(w http.ResponseWriter, r *http.Request) {
+	switch r.Method {
+	case "POST":
+		query := r.URL.Query()
+		if query.Get("src") != "" {
+			// WHEP or JSON SDP or raw SDP exchange
+			outputWebRTC(w, r)
+		} else if query.Get("dst") != "" {
+			// WHIP SDP exchange
+			inputWebRTC(w, r)
+		} else {
+			http.Error(w, "", http.StatusBadRequest)
+		}
+
+	case "PATCH":
+		// TODO: WHEP/WHIP
+		http.Error(w, "", http.StatusMethodNotAllowed)
+
+	case "DELETE":
+		if id := r.URL.Query().Get("id"); id != "" {
+			if conn, ok := sessions[id]; ok {
+				delete(sessions, id)
+				_ = conn.Close()
+			} else {
+				http.Error(w, "", http.StatusNotFound)
+			}
+		} else {
+			http.Error(w, "", http.StatusBadRequest)
+		}
+
+	default:
+		http.Error(w, "", http.StatusMethodNotAllowed)
+	}
+}
+
+// outputWebRTC support API depending on Content-Type:
+// 1. application/json - receive {"type":"offer","sdp":"v=0\r\n..."} and response {"type":"answer","sdp":"v=0\r\n..."}
+// 2. application/sdp - receive/response SDP via WebRTC-HTTP Egress Protocol (WHEP)
+// 3. other - receive/response raw SDP
+func outputWebRTC(w http.ResponseWriter, r *http.Request) {
+	url := r.URL.Query().Get("src")
+	stream := streams.Get(url)
+	if stream == nil {
+		return
+	}
+
+	mediaType := r.Header.Get("Content-Type")
+	if mediaType != "" {
+		mediaType, _, _ = strings.Cut(mediaType, ";")
+		mediaType = strings.ToLower(strings.TrimSpace(mediaType))
+	}
+
+	var offer string
+
+	switch mediaType {
+	case "application/json":
+		var desc pion.SessionDescription
+		if err := json.NewDecoder(r.Body).Decode(&desc); err != nil {
+			log.Error().Err(err).Caller().Send()
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		offer = desc.SDP
+
+	default:
+		body, err := io.ReadAll(r.Body)
+		if err != nil {
+			log.Error().Err(err).Caller().Send()
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		offer = string(body)
+	}
+
+	answer, err := ExchangeSDP(stream, offer, r.UserAgent())
+	if err != nil {
+		log.Error().Err(err).Caller().Send()
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	switch mediaType {
+	case "application/json":
+		w.Header().Set("Content-Type", mediaType)
+
+		v := pion.SessionDescription{
+			Type: pion.SDPTypeAnswer, SDP: answer,
+		}
+		err = json.NewEncoder(w).Encode(v)
+
+	case MimeSDP:
+		w.Header().Set("Content-Type", mediaType)
+		w.WriteHeader(http.StatusCreated)
+
+		_, err = w.Write([]byte(answer))
+
+	default:
+		_, err = w.Write([]byte(answer))
+	}
+
+	if err != nil {
+		log.Error().Err(err).Caller().Send()
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+}
+
+func inputWebRTC(w http.ResponseWriter, r *http.Request) {
+	dst := r.URL.Query().Get("dst")
+	stream := streams.Get(dst)
+	if stream == nil {
+		stream = streams.New(dst, nil)
+	}
+
+	// 1. Get offer
+	offer, err := io.ReadAll(r.Body)
+	if err != nil {
+		log.Error().Err(err).Caller().Send()
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	log.Trace().Msgf("[webrtc] WHIP offer\n%s", offer)
+
+	pc, err := newPeerConnection()
+	if err != nil {
+		log.Error().Err(err).Caller().Send()
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// create new webrtc instance
+	conn := webrtc.NewConn(pc)
+	conn.UserAgent = r.UserAgent()
+
+	if err = conn.SetOffer(string(offer)); err != nil {
+		log.Warn().Err(err).Caller().Send()
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	answer, err := conn.GetCompleteAnswer()
+	if err == nil {
+		answer, err = syncCanditates(answer)
+	}
+	if err != nil {
+		log.Warn().Err(err).Caller().Send()
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	log.Trace().Msgf("[webrtc] WHIP answer\n%s", answer)
+
+	id := strconv.FormatInt(time.Now().UnixNano(), 36)
+	sessions[id] = conn
+
+	conn.Listen(func(msg interface{}) {
+		switch msg := msg.(type) {
+		case pion.PeerConnectionState:
+			if msg == pion.PeerConnectionStateClosed {
+				stream.RemoveProducer(conn)
+				if _, ok := sessions[id]; ok {
+					delete(sessions, id)
+				}
+			}
+		}
+	})
+
+	stream.AddProducer(conn)
+
+	w.Header().Set("Content-Type", MimeSDP)
+	w.Header().Set("Location", "webrtc?id="+id)
+	w.WriteHeader(http.StatusCreated)
+
+	if _, err = w.Write([]byte(answer)); err != nil {
+		log.Warn().Err(err).Caller().Send()
+		return
+	}
+}