server: support reading back channels (#597) (#777)

examples/proxy-backchannel/server.go

@@ -0,0 +1,134 @@
+package main
+
+import (
+	"log"
+	"sync"
+
+	"github.com/bluenviron/gortsplib/v4"
+	"github.com/bluenviron/gortsplib/v4/pkg/base"
+	"github.com/bluenviron/gortsplib/v4/pkg/description"
+	"github.com/bluenviron/gortsplib/v4/pkg/format"
+	"github.com/pion/rtp"
+)
+
+type server struct {
+	server        *gortsplib.Server
+	mutex         sync.RWMutex
+	stream        *gortsplib.ServerStream
+	writeToClient func(*rtp.Packet)
+}
+
+func (s *server) initialize() {
+	// configure the server
+	s.server = &gortsplib.Server{
+		Handler:           s,
+		RTSPAddress:       ":8556",
+		UDPRTPAddress:     ":8002",
+		UDPRTCPAddress:    ":8003",
+		MulticastIPRange:  "224.1.0.0/16",
+		MulticastRTPPort:  8002,
+		MulticastRTCPPort: 8003,
+	}
+}
+
+// called when a connection is opened.
+func (s *server) OnConnOpen(ctx *gortsplib.ServerHandlerOnConnOpenCtx) {
+	log.Printf("conn opened")
+}
+
+// called when a connection is closed.
+func (s *server) OnConnClose(ctx *gortsplib.ServerHandlerOnConnCloseCtx) {
+	log.Printf("conn closed (%v)", ctx.Error)
+}
+
+// called when a session is opened.
+func (s *server) OnSessionOpen(ctx *gortsplib.ServerHandlerOnSessionOpenCtx) {
+	log.Printf("session opened")
+}
+
+// called when a session is closed.
+func (s *server) OnSessionClose(ctx *gortsplib.ServerHandlerOnSessionCloseCtx) {
+	log.Printf("session closed")
+}
+
+// called when receiving a DESCRIBE request.
+func (s *server) OnDescribe(ctx *gortsplib.ServerHandlerOnDescribeCtx) (*base.Response, *gortsplib.ServerStream, error) {
+	log.Printf("DESCRIBE request")
+
+	s.mutex.RLock()
+	defer s.mutex.RUnlock()
+
+	// stream is not available yet
+	if s.stream == nil {
+		return &base.Response{
+			StatusCode: base.StatusNotFound,
+		}, nil, nil
+	}
+
+	return &base.Response{
+		StatusCode: base.StatusOK,
+	}, s.stream, nil
+}
+
+// called when receiving a SETUP request.
+func (s *server) OnSetup(ctx *gortsplib.ServerHandlerOnSetupCtx) (*base.Response, *gortsplib.ServerStream, error) {
+	log.Printf("SETUP request")
+
+	s.mutex.RLock()
+	defer s.mutex.RUnlock()
+
+	// stream is not available yet
+	if s.stream == nil {
+		return &base.Response{
+			StatusCode: base.StatusNotFound,
+		}, nil, nil
+	}
+
+	return &base.Response{
+		StatusCode: base.StatusOK,
+	}, s.stream, nil
+}
+
+// called when receiving a PLAY request.
+func (s *server) OnPlay(ctx *gortsplib.ServerHandlerOnPlayCtx) (*base.Response, error) {
+	log.Printf("PLAY request")
+
+	ctx.Session.OnPacketRTPAny(func(m *description.Media, f format.Format, pkt *rtp.Packet) {
+		log.Printf("received RTP packet from readers, routing to the client")
+
+		s.writeToClient(pkt)
+	})
+
+	return &base.Response{
+		StatusCode: base.StatusOK,
+	}, nil
+}
+
+func (s *server) setStreamReady(
+	desc *description.Session,
+	writeToClient func(*rtp.Packet),
+) *gortsplib.ServerStream {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
+	s.stream = &gortsplib.ServerStream{
+		Server: s.server,
+		Desc:   desc,
+	}
+	err := s.stream.Initialize()
+	if err != nil {
+		panic(err)
+	}
+
+	s.writeToClient = writeToClient
+
+	return s.stream
+}
+
+func (s *server) setStreamUnready() {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
+	s.stream.Close()
+	s.stream = nil
+}