public async Task <ICallInfo> PlaceCallAsync(CallConfiguration config)
{
Debug.Assert(_peerId == -1);
if (PeerConnection != null)
{
Debug.WriteLine("[Error] We only support connection to one peer at a time.");
return(null);
}
if (CreatePeerConnection())
{
string selectedAudioCodecName = (string)_localSettings.Values["SelectedAudioCodecName"];
string selectedVideoCodecName = (string)_localSettings.Values["SelectedVideoCodecName"];
_peerId = PeerId;
var offerOptions = new RTCOfferOptions();
offerOptions.OfferToReceiveAudio = true;
offerOptions.OfferToReceiveVideo = true;
IRTCSessionDescription offer = await PeerConnection.CreateOffer(offerOptions);
// Alter sdp to force usage of selected codecs
string modifiedSdp = offer.Sdp;
SdpUtils.SelectCodec(ref modifiedSdp, selectedAudioCodecName, "audio");
SdpUtils.SelectCodec(ref modifiedSdp, selectedVideoCodecName, "video");
RTCSessionDescriptionInit sdpInit = new RTCSessionDescriptionInit();
sdpInit.Sdp = modifiedSdp;
sdpInit.Type = offer.SdpType;
var modifiedOffer = new RTCSessionDescription(sdpInit);
await PeerConnection.SetLocalDescription(modifiedOffer);
Debug.WriteLine($"Sending offer: {modifiedOffer.Sdp}");
string jsonString = SdpToJsonString(modifiedOffer);
CallInfo callInfo = new CallInfo();
callInfo.SetCall(new Call());
callInfo.SetSdp(modifiedSdp);
callInfo.SetJsonString(jsonString);
OnSendMessageToRemotePeer.Invoke(this, jsonString);
return(callInfo);
}
return(null);
}
/// <summary>
/// Called when WebRTC detects another ICE candidate.
/// This candidate needs to be sent to the other peer.
/// </summary>
/// <param name="Event">Details about RTCPeerConnectionIceEvent</param>
private void PeerConnection_OnIceCandidate(IRTCPeerConnectionIceEvent Event)
{
if (Event.Candidate == null)
{
return;
}
double index = (double)Event.Candidate.SdpMLineIndex;
JsonObject json = null;
json = new JsonObject
{
{ NegotiationAtributes.SdpMid, JsonValue.CreateStringValue(Event.Candidate.SdpMid) },
{ NegotiationAtributes.SdpMLineIndex, JsonValue.CreateNumberValue(index) },
{ NegotiationAtributes.Candidate, JsonValue.CreateStringValue(Event.Candidate.Candidate) }
};
Debug.WriteLine($"Send ice candidate:\n{json.Stringify()}");
OnSendMessageToRemotePeer.Invoke(this, json.Stringify());
}
public void MessageFromPeerTaskRun(int peerId, string content)
{
PeerId = peerId;
Task.Run(async() =>
{
Debug.Assert(_peerId == PeerId || _peerId == -1);
Debug.Assert(content.Length > 0);
if (_peerId != PeerId && _peerId != -1)
{
Debug.WriteLine("Received a message from unknown peer " +
"while already in a conversation with a different peer.");
return;
}
if (!JsonObject.TryParse(content, out JsonObject jMessage))
{
Debug.WriteLine($"Received unknown message: {content}");
return;
}
string type = jMessage.ContainsKey(NegotiationAtributes.Type)
? jMessage.GetNamedString(NegotiationAtributes.Type)
: null;
if (PeerConnection == null)
{
if (!string.IsNullOrEmpty(type))
{
// Create the peer connection only when call is
// about to get initiated. Otherwise ignore the
// message from peers which could be result
// of old (but not yet fully closed) connections.
if (type == "offer" || type == "answer" || type == "json")
{
Debug.Assert(_peerId == -1);
_peerId = PeerId;
if (!CreatePeerConnection())
{
Debug.WriteLine("Failed to initialize our PeerConnection instance");
OnSignedOut.Invoke(this, null);
return;
}
else if (_peerId != PeerId)
{
Debug.WriteLine("Received a message from unknown peer while already " +
"in a conversation with a different peer.");
return;
}
}
}
else
{
Debug.WriteLine("[Warn] Received an untyped message after closing peer connection.");
return;
}
}
if (PeerConnection != null && !string.IsNullOrEmpty(type))
{
if (type == "offer-loopback")
{
// Loopback not supported
Debug.Assert(false);
}
string sdp = null;
sdp = jMessage.ContainsKey(NegotiationAtributes.Sdp)
? jMessage.GetNamedString(NegotiationAtributes.Sdp)
: null;
if (string.IsNullOrEmpty(sdp))
{
Debug.WriteLine("[Error] Can't parse received session description message.");
return;
}
Debug.WriteLine($"Received session description:\n{content}");
RTCSdpType messageType = RTCSdpType.Offer;
switch (type)
{
case "offer": messageType = RTCSdpType.Offer; break;
case "answer": messageType = RTCSdpType.Answer; break;
case "pranswer": messageType = RTCSdpType.Pranswer; break;
default: Debug.Assert(false, type); break;
}
var sdpInit = new RTCSessionDescriptionInit();
sdpInit.Sdp = sdp;
sdpInit.Type = messageType;
var description = new RTCSessionDescription(sdpInit);
await PeerConnection.SetRemoteDescription(description);
if (messageType == RTCSdpType.Offer)
{
var answerOptions = new RTCAnswerOptions();
IRTCSessionDescription answer = await PeerConnection.CreateAnswer(answerOptions);
await PeerConnection.SetLocalDescription(answer);
string jsonString = SdpToJsonString(answer);
// Send answer
OnSendMessageToRemotePeer.Invoke(this, jsonString);
}
}
else
{
RTCIceCandidate candidate = null;
string sdpMid = jMessage.ContainsKey(NegotiationAtributes.SdpMid)
? jMessage.GetNamedString(NegotiationAtributes.SdpMid)
: null;
double sdpMLineIndex = jMessage.ContainsKey(NegotiationAtributes.SdpMLineIndex)
? jMessage.GetNamedNumber(NegotiationAtributes.SdpMLineIndex)
: -1;
string sdpCandidate = jMessage.ContainsKey(NegotiationAtributes.Candidate)
? jMessage.GetNamedString(NegotiationAtributes.Candidate)
: null;
if (string.IsNullOrEmpty(sdpMid) || sdpMLineIndex == -1 || string.IsNullOrEmpty(sdpCandidate))
{
Debug.WriteLine($"[Error] Can't parse received message.\n{content}");
return;
}
var candidateInit = new RTCIceCandidateInit();
candidateInit.Candidate = sdpCandidate;
candidateInit.SdpMid = sdpMid;
candidateInit.SdpMLineIndex = (ushort)sdpMLineIndex;
candidate = new RTCIceCandidate(candidateInit);
await PeerConnection.AddIceCandidate(candidate);
Debug.WriteLine($"Receiving ice candidate:\n{content}");
}
}).Wait();
}
