Implement WASM Media methods

Add AddTransceiverFromKind and GetTransceivers. This doesn't support
everything, but enough to at least build a recvonly experience.

Resolves #500

peerconnection.go

@@ -1637,7 +1637,7 @@ func (pc *PeerConnection) RemoveTrack(sender *RTPSender) (err error) {
 	return nil
 }
 
-// AddTransceiverFromKind Create a new RtpTransceiver(SendRecv or RecvOnly) and add it to the set of transceivers.
+// AddTransceiverFromKind Create a new RtpTransceiver and adds it to the set of transceivers.
 func (pc *PeerConnection) AddTransceiverFromKind(kind RTPCodecType, init ...RtpTransceiverInit) (*RTPTransceiver, error) {
 	if pc.isClosed.get() {
 		return nil, &rtcerr.InvalidStateError{Err: ErrConnectionClosed}
@@ -1651,7 +1651,7 @@ func (pc *PeerConnection) AddTransceiverFromKind(kind RTPCodecType, init ...RtpT
 	}
 
 	switch direction {
-	case RTPTransceiverDirectionSendrecv:
+	case RTPTransceiverDirectionSendonly, RTPTransceiverDirectionSendrecv:
 		codecs := pc.api.mediaEngine.getCodecsByKind(kind)
 		if len(codecs) == 0 {
 			return nil, ErrNoCodecsAvailable

peerconnection_js.go

@@ -488,6 +488,40 @@ func (pc *PeerConnection) setGatherCompleteHandler(handler func()) {
 	}
 }
 
+// AddTransceiverFromKind Create a new RtpTransceiver and adds it to the set of transceivers.
+func (pc *PeerConnection) AddTransceiverFromKind(kind RTPCodecType, init ...RtpTransceiverInit) (transceiver *RTPTransceiver, err error) {
+	defer func() {
+		if e := recover(); e != nil {
+			err = recoveryToError(e)
+		}
+	}()
+
+	if len(init) == 1 {
+		return &RTPTransceiver{
+			underlying: pc.underlying.Call("addTransceiver", kind.String(), rtpTransceiverInitInitToValue(init[0])),
+		}, err
+
+	}
+
+	return &RTPTransceiver{
+		underlying: pc.underlying.Call("addTransceiver", kind.String()),
+	}, err
+}
+
+// GetTransceivers returns the RtpTransceiver that are currently attached to this PeerConnection
+func (pc *PeerConnection) GetTransceivers() (transceivers []*RTPTransceiver) {
+	rawTransceivers := pc.underlying.Call("getTransceivers")
+	transceivers = make([]*RTPTransceiver, rawTransceivers.Length())
+
+	for i := 0; i < rawTransceivers.Length(); i++ {
+		transceivers[i] = &RTPTransceiver{
+			underlying: rawTransceivers.Index(i),
+		}
+	}
+
+	return
+}
+
 // Converts a Configuration to js.Value so it can be passed
 // through to the JavaScript WebRTC API. Any zero values are converted to
 // js.Undefined(), which will result in the default value being used.
@@ -674,3 +708,9 @@ func dataChannelInitToValue(options *DataChannelInit) js.Value {
 		"id":                uint16PointerToValue(options.ID),
 	})
 }
+
+func rtpTransceiverInitInitToValue(init RtpTransceiverInit) js.Value {
+	return js.ValueOf(map[string]interface{}{
+		"direction": init.Direction.String(),
+	})
+}

peerconnection_media_test.go

@@ -29,16 +29,6 @@ var (
 	errNoTransceiverwithMid      = errors.New("no transceiver with mid")
 )
 
-func offerMediaHasDirection(offer SessionDescription, kind RTPCodecType, direction RTPTransceiverDirection) bool {
-	for _, media := range offer.parsed.MediaDescriptions {
-		if media.MediaName.Media == kind.String() {
-			_, exists := media.Attribute(direction.String())
-			return exists
-		}
-	}
-	return false
-}
-
 /*
 Integration test for bi-directional peers
 
@@ -567,45 +557,6 @@ func TestAddTransceiverFromTrackSendRecv(t *testing.T) {
 	assert.NoError(t, pc.Close())
 }
 
-// nolint: dupl
-func TestAddTransceiver(t *testing.T) {
-	lim := test.TimeOut(time.Second * 30)
-	defer lim.Stop()
-
-	report := test.CheckRoutines(t)
-	defer report()
-
-	pc, err := NewPeerConnection(Configuration{})
-	if err != nil {
-		t.Error(err.Error())
-	}
-
-	transceiver, err := pc.AddTransceiverFromKind(RTPCodecTypeVideo, RtpTransceiverInit{
-		Direction: RTPTransceiverDirectionSendrecv,
-	})
-	if err != nil {
-		t.Error(err.Error())
-	}
-
-	if transceiver.Receiver() == nil {
-		t.Errorf("Transceiver should have a receiver")
-	}
-
-	if transceiver.Sender() == nil {
-		t.Errorf("Transceiver should have a sender")
-	}
-
-	offer, err := pc.CreateOffer(nil)
-	if err != nil {
-		t.Error(err.Error())
-	}
-
-	if !offerMediaHasDirection(offer, RTPCodecTypeVideo, RTPTransceiverDirectionSendrecv) {
-		t.Errorf("Direction on SDP is not %s", RTPTransceiverDirectionSendrecv)
-	}
-	assert.NoError(t, pc.Close())
-}
-
 func TestAddTransceiverAddTrack_Reuse(t *testing.T) {
 	pc, err := NewPeerConnection(Configuration{})
 	assert.NoError(t, err)
@@ -730,30 +681,6 @@ func TestAddTransceiverFromKind(t *testing.T) {
 	assert.NoError(t, pc.Close())
 }
 
-func TestAddTransceiverFromKindFailsSendOnly(t *testing.T) {
-	lim := test.TimeOut(time.Second * 30)
-	defer lim.Stop()
-
-	report := test.CheckRoutines(t)
-	defer report()
-
-	pc, err := NewPeerConnection(Configuration{})
-	if err != nil {
-		t.Error(err.Error())
-	}
-
-	transceiver, err := pc.AddTransceiverFromKind(RTPCodecTypeVideo, RtpTransceiverInit{
-		Direction: RTPTransceiverDirectionSendonly,
-	})
-
-	if transceiver != nil {
-		t.Error("AddTransceiverFromKind shouldn't succeed with Direction RTPTransceiverDirectionSendonly")
-	}
-
-	assert.NotNil(t, err)
-	assert.NoError(t, pc.Close())
-}
-
 func TestAddTransceiverFromTrackFailsRecvOnly(t *testing.T) {
 	lim := test.TimeOut(time.Second * 30)
 	defer lim.Stop()

peerconnection_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/pion/sdp/v3"
 	"github.com/pion/transport/test"
 	"github.com/pion/webrtc/v3/pkg/rtcerr"
 	"github.com/stretchr/testify/assert"
@@ -61,6 +62,21 @@ func signalPair(pcOffer *PeerConnection, pcAnswer *PeerConnection) error {
 	return pcOffer.SetRemoteDescription(*pcAnswer.LocalDescription())
 }
 
+func offerMediaHasDirection(offer SessionDescription, kind RTPCodecType, direction RTPTransceiverDirection) bool {
+	parsed := &sdp.SessionDescription{}
+	if err := parsed.Unmarshal([]byte(offer.SDP)); err != nil {
+		return false
+	}
+
+	for _, media := range parsed.MediaDescriptions {
+		if media.MediaName.Media == kind.String() {
+			_, exists := media.Attribute(direction.String())
+			return exists
+		}
+	}
+	return false
+}
+
 func TestNew(t *testing.T) {
 	pc, err := NewPeerConnection(Configuration{
 		ICEServers: []ICEServer{
@@ -650,3 +666,42 @@ func TestSetRemoteDescriptionInvalid(t *testing.T) {
 		assert.NoError(t, pc.Close())
 	})
 }
+
+// nolint: dupl
+func TestAddTransceiver(t *testing.T) {
+	lim := test.TimeOut(time.Second * 30)
+	defer lim.Stop()
+
+	report := test.CheckRoutines(t)
+	defer report()
+
+	pc, err := NewPeerConnection(Configuration{})
+	if err != nil {
+		t.Error(err.Error())
+	}
+
+	transceiver, err := pc.AddTransceiverFromKind(RTPCodecTypeVideo, RtpTransceiverInit{
+		Direction: RTPTransceiverDirectionSendrecv,
+	})
+	if err != nil {
+		t.Error(err.Error())
+	}
+
+	if transceiver.Receiver() == nil {
+		t.Errorf("Transceiver should have a receiver")
+	}
+
+	if transceiver.Sender() == nil {
+		t.Errorf("Transceiver should have a sender")
+	}
+
+	offer, err := pc.CreateOffer(nil)
+	if err != nil {
+		t.Error(err.Error())
+	}
+
+	if !offerMediaHasDirection(offer, RTPCodecTypeVideo, RTPTransceiverDirectionSendrecv) {
+		t.Errorf("Direction on SDP is not %s", RTPTransceiverDirectionSendrecv)
+	}
+	assert.NoError(t, pc.Close())
+}

rtpreceiver_js.go

@@ -0,0 +1,11 @@
+// +build js,wasm
+
+package webrtc
+
+import "syscall/js"
+
+// RTPReceiver allows an application to inspect the receipt of a TrackRemote
+type RTPReceiver struct {
+	// Pointer to the underlying JavaScript RTCRTPReceiver object.
+	underlying js.Value
+}

rtpsender_js.go

@@ -0,0 +1,11 @@
+// +build js,wasm
+
+package webrtc
+
+import "syscall/js"
+
+// RTPSender allows an application to control how a given Track is encoded and transmitted to a remote peer
+type RTPSender struct {
+	// Pointer to the underlying JavaScript RTCRTPSender object.
+	underlying js.Value
+}

rtptransceiver_js.go

@@ -0,0 +1,36 @@
+// +build js,wasm
+
+package webrtc
+
+import "syscall/js"
+
+// RTPTransceiver represents a combination of an RTPSender and an RTPReceiver that share a common mid.
+type RTPTransceiver struct {
+	// Pointer to the underlying JavaScript RTCRTPTransceiver object.
+	underlying js.Value
+}
+
+// Direction returns the RTPTransceiver's current direction
+func (r *RTPTransceiver) Direction() RTPTransceiverDirection {
+	return NewRTPTransceiverDirection(r.underlying.Get("direction").String())
+}
+
+// Sender returns the RTPTransceiver's RTPSender if it has one
+func (r *RTPTransceiver) Sender() *RTPSender {
+	underlying := r.underlying.Get("sender")
+	if underlying.IsNull() {
+		return nil
+	}
+
+	return &RTPSender{underlying: underlying}
+}
+
+// Receiver returns the RTPTransceiver's RTPReceiver if it has one
+func (r *RTPTransceiver) Receiver() *RTPReceiver {
+	underlying := r.underlying.Get("receiver")
+	if underlying.IsNull() {
+		return nil
+	}
+
+	return &RTPReceiver{underlying: underlying}
+}