support receiving single tracks (#48)

client.go

@@ -7,6 +7,7 @@ import (
 	"net"
 	"os"
 	"os/exec"
+	"strconv"
 	"strings"
 	"time"
 
@@ -88,7 +89,7 @@ type client struct {
 	authHelper     *gortsplib.AuthServer
 	authFailures   int
 	streamProtocol gortsplib.StreamProtocol
-	streamTracks   []*clientTrack
+	streamTracks   map[int]*clientTrack
 	rtcpReceivers  []*gortsplib.RtcpReceiver
 	readBuf        *doubleBuffer
 	writeBuf       *doubleBuffer
@@ -107,6 +108,7 @@ func newClient(p *program, nconn net.Conn) *client {
 			WriteTimeout: p.conf.WriteTimeout,
 		}),
 		state:        clientStateInitial,
+		streamTracks: make(map[int]*clientTrack),
 		readBuf:      newDoubleBuffer(clientTcpReadBufferSize),
 		done:         make(chan struct{}),
 	}
@@ -433,7 +435,7 @@ func (c *client) handleRequest(req *gortsplib.Request) bool {
 			return false
 		}
 
-		basePath, _, err := splitPath(path)
+		basePath, controlPath, err := splitPath(path)
 		if err != nil {
 			c.writeResError(req, gortsplib.StatusBadRequest, err)
 			return false
@@ -457,6 +459,28 @@ func (c *client) handleRequest(req *gortsplib.Request) bool {
 				return true
 			}
 
+			if c.pathId != "" && basePath != c.pathId {
+				c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("path has changed, was '%s', now is '%s'", c.pathId, basePath))
+				return false
+			}
+
+			if !strings.HasPrefix(controlPath, "trackID=") {
+				c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("invalid control path (%s)", controlPath))
+				return false
+			}
+
+			tmp, err := strconv.ParseInt(controlPath[len("trackID="):], 10, 64)
+			if err != nil || tmp < 0 {
+				c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("invalid track id (%s)", controlPath))
+				return false
+			}
+			trackId := int(tmp)
+
+			if _, ok := c.streamTracks[trackId]; ok {
+				c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("track %d has already been setup", trackId))
+				return false
+			}
+
 			// play via UDP
 			if func() bool {
 				_, ok := th["RTP/AVP"]
@@ -474,30 +498,31 @@ func (c *client) handleRequest(req *gortsplib.Request) bool {
 					return false
 				}
 
-				rtpPort, rtcpPort := th.Ports("client_port")
-				if rtpPort == 0 || rtcpPort == 0 {
-					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("transport header does not have valid client ports (%v)", req.Header["Transport"]))
-					return false
-				}
-
-				if c.pathId != "" && basePath != c.pathId {
-					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("path has changed, was '%s', now is '%s'", c.pathId, basePath))
+				if len(c.streamTracks) > 0 && c.streamProtocol != gortsplib.StreamProtocolUdp {
+					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("can't receive tracks with different protocols"))
 					return false
 				}
 
-				if len(c.streamTracks) > 0 && c.streamProtocol != gortsplib.StreamProtocolUdp {
-					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("can't receive tracks with different protocols"))
+				rtpPort, rtcpPort := th.Ports("client_port")
+				if rtpPort == 0 || rtcpPort == 0 {
+					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("transport header does not have valid client ports (%v)", req.Header["Transport"]))
 					return false
 				}
 
 				res := make(chan error)
-				c.p.events <- programEventClientSetupPlay{res, c, basePath, gortsplib.StreamProtocolUdp, rtpPort, rtcpPort}
+				c.p.events <- programEventClientSetupPlay{res, c, basePath, trackId}
 				err = <-res
 				if err != nil {
 					c.writeResError(req, gortsplib.StatusBadRequest, err)
 					return false
 				}
 
+				c.streamProtocol = gortsplib.StreamProtocolUdp
+				c.streamTracks[trackId] = &clientTrack{
+					rtpPort:  rtpPort,
+					rtcpPort: rtcpPort,
+				}
+
 				c.conn.WriteResponse(&gortsplib.Response{
 					StatusCode: gortsplib.StatusOK,
 					Header: gortsplib.Header{
@@ -520,25 +545,26 @@ func (c *client) handleRequest(req *gortsplib.Request) bool {
 					return false
 				}
 
-				if c.pathId != "" && basePath != c.pathId {
-					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("path has changed, was '%s', now is '%s'", c.pathId, basePath))
-					return false
-				}
-
 				if len(c.streamTracks) > 0 && c.streamProtocol != gortsplib.StreamProtocolTcp {
 					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("can't receive tracks with different protocols"))
 					return false
 				}
 
 				res := make(chan error)
-				c.p.events <- programEventClientSetupPlay{res, c, basePath, gortsplib.StreamProtocolTcp, 0, 0}
+				c.p.events <- programEventClientSetupPlay{res, c, basePath, trackId}
 				err = <-res
 				if err != nil {
 					c.writeResError(req, gortsplib.StatusBadRequest, err)
 					return false
 				}
 
-				interleaved := fmt.Sprintf("%d-%d", ((len(c.streamTracks) - 1) * 2), ((len(c.streamTracks)-1)*2)+1)
+				c.streamProtocol = gortsplib.StreamProtocolTcp
+				c.streamTracks[trackId] = &clientTrack{
+					rtpPort:  0,
+					rtcpPort: 0,
+				}
+
+				interleaved := fmt.Sprintf("%d-%d", ((trackId) * 2), ((trackId)*2)+1)
 
 				c.conn.WriteResponse(&gortsplib.Response{
 					StatusCode: gortsplib.StatusOK,
@@ -589,14 +615,14 @@ func (c *client) handleRequest(req *gortsplib.Request) bool {
 					return false
 				}
 
-				rtpPort, rtcpPort := th.Ports("client_port")
-				if rtpPort == 0 || rtcpPort == 0 {
-					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("transport header does not have valid client ports (%s)", req.Header["Transport"]))
+				if len(c.streamTracks) > 0 && c.streamProtocol != gortsplib.StreamProtocolUdp {
+					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("can't publish tracks with different protocols"))
 					return false
 				}
 
-				if len(c.streamTracks) > 0 && c.streamProtocol != gortsplib.StreamProtocolUdp {
-					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("can't publish tracks with different protocols"))
+				rtpPort, rtcpPort := th.Ports("client_port")
+				if rtpPort == 0 || rtcpPort == 0 {
+					c.writeResError(req, gortsplib.StatusBadRequest, fmt.Errorf("transport header does not have valid client ports (%s)", req.Header["Transport"]))
 					return false
 				}
 
@@ -606,13 +632,19 @@ func (c *client) handleRequest(req *gortsplib.Request) bool {
 				}
 
 				res := make(chan error)
-				c.p.events <- programEventClientSetupRecord{res, c, gortsplib.StreamProtocolUdp, rtpPort, rtcpPort}
+				c.p.events <- programEventClientSetupRecord{res, c}
 				err := <-res
 				if err != nil {
 					c.writeResError(req, gortsplib.StatusBadRequest, err)
 					return false
 				}
 
+				c.streamProtocol = gortsplib.StreamProtocolUdp
+				c.streamTracks[len(c.streamTracks)] = &clientTrack{
+					rtpPort:  rtpPort,
+					rtcpPort: rtcpPort,
+				}
+
 				c.conn.WriteResponse(&gortsplib.Response{
 					StatusCode: gortsplib.StatusOK,
 					Header: gortsplib.Header{
@@ -658,13 +690,19 @@ func (c *client) handleRequest(req *gortsplib.Request) bool {
 				}
 
 				res := make(chan error)
-				c.p.events <- programEventClientSetupRecord{res, c, gortsplib.StreamProtocolTcp, 0, 0}
+				c.p.events <- programEventClientSetupRecord{res, c}
 				err := <-res
 				if err != nil {
 					c.writeResError(req, gortsplib.StatusBadRequest, err)
 					return false
 				}
 
+				c.streamProtocol = gortsplib.StreamProtocolTcp
+				c.streamTracks[len(c.streamTracks)] = &clientTrack{
+					rtpPort:  0,
+					rtcpPort: 0,
+				}
+
 				c.conn.WriteResponse(&gortsplib.Response{
 					StatusCode: gortsplib.StatusOK,
 					Header: gortsplib.Header{
@@ -776,6 +814,7 @@ func (c *client) runPlay(path string) {
 		c.events = make(chan clientEvent)
 	}
 
+	// start sending frames only after sending the response to the PLAY request
 	done := make(chan struct{})
 	c.p.events <- programEventClientPlay2{done, c}
 	<-done

main.go

@@ -73,9 +73,7 @@ type programEventClientSetupPlay struct {
 	res     chan error
 	client  *client
 	path    string
-	protocol gortsplib.StreamProtocol
-	rtpPort  int
-	rtcpPort int
+	trackId int
 }
 
 func (programEventClientSetupPlay) isProgramEvent() {}
@@ -83,9 +81,6 @@ func (programEventClientSetupPlay) isProgramEvent() {}
 type programEventClientSetupRecord struct {
 	res    chan error
 	client *client
-	protocol gortsplib.StreamProtocol
-	rtpPort  int
-	rtcpPort int
 }
 
 func (programEventClientSetupRecord) isProgramEvent() {}
@@ -384,26 +379,16 @@ outer:
 					continue
 				}
 
-				if len(evt.client.streamTracks) >= len(path.publisherSdpParsed.MediaDescriptions) {
-					evt.res <- fmt.Errorf("all the tracks have already been setup")
+				if evt.trackId >= len(path.publisherSdpParsed.MediaDescriptions) {
+					evt.res <- fmt.Errorf("track %d does not exist", evt.trackId)
 					continue
 				}
 
 				evt.client.pathId = evt.path
-				evt.client.streamProtocol = evt.protocol
-				evt.client.streamTracks = append(evt.client.streamTracks, &clientTrack{
-					rtpPort:  evt.rtpPort,
-					rtcpPort: evt.rtcpPort,
-				})
 				evt.client.state = clientStatePrePlay
 				evt.res <- nil
 
 			case programEventClientSetupRecord:
-				evt.client.streamProtocol = evt.protocol
-				evt.client.streamTracks = append(evt.client.streamTracks, &clientTrack{
-					rtpPort:  evt.rtpPort,
-					rtcpPort: evt.rtcpPort,
-				})
 				evt.client.state = clientStatePreRecord
 				evt.res <- nil
 
@@ -414,8 +399,8 @@ outer:
 					continue
 				}
 
-				if len(evt.client.streamTracks) != len(path.publisherSdpParsed.MediaDescriptions) {
-					evt.res <- fmt.Errorf("not all tracks have been setup")
+				if len(evt.client.streamTracks) == 0 {
+					evt.res <- fmt.Errorf("no tracks have been setup")
 					continue
 				}
 
@@ -589,14 +574,23 @@ func (p *program) findClientPublisher(addr *net.UDPAddr, streamType gortsplib.St
 
 func (p *program) forwardFrame(path string, trackId int, streamType gortsplib.StreamType, frame []byte) {
 	for c := range p.clients {
-		if c.pathId == path && c.state == clientStatePlay {
+		if c.pathId != path ||
+			c.state != clientStatePlay {
+			continue
+		}
+
+		track, ok := c.streamTracks[trackId]
+		if !ok {
+			continue
+		}
+
 		if c.streamProtocol == gortsplib.StreamProtocolUdp {
 			if streamType == gortsplib.StreamTypeRtp {
 				p.serverRtp.write(&udpAddrBufPair{
 					addr: &net.UDPAddr{
 						IP:   c.ip(),
 						Zone: c.zone(),
-							Port: c.streamTracks[trackId].rtpPort,
+						Port: track.rtpPort,
 					},
 					buf: frame,
 				})
@@ -605,7 +599,7 @@ func (p *program) forwardFrame(path string, trackId int, streamType gortsplib.St
 					addr: &net.UDPAddr{
 						IP:   c.ip(),
 						Zone: c.zone(),
-							Port: c.streamTracks[trackId].rtcpPort,
+						Port: track.rtcpPort,
 					},
 					buf: frame,
 				})
@@ -626,7 +620,6 @@ func (p *program) forwardFrame(path string, trackId int, streamType gortsplib.St
 		}
 	}
 }
-}
 
 func main() {
 	_, err := newProgram(os.Args[1:], os.Stdin)

utils.go

@@ -110,7 +110,7 @@ func sdpForServer(tracks []*gortsplib.Track) (*sdp.SessionDescription, []byte) {
 					}
 				}
 
-				// control attribute is mandatory, and is the path that is appended
+				// control attribute is the path that is appended
 				// to the stream path in SETUP
 				ret = append(ret, sdp.Attribute{
 					Key:   "control",