VoIP: fix call candidate parsing

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/call/CallCandidate.kt

@@ -24,13 +24,13 @@ data class CallCandidate(
         /**
          * Required. The SDP media type this candidate is intended for.
          */
-        @Json(name = "sdpMid") val sdpMid: String,
+        @Json(name = "sdpMid") val sdpMid: String? = null,
         /**
          * Required. The index of the SDP 'm' line this candidate is intended for.
          */
-        @Json(name = "sdpMLineIndex") val sdpMLineIndex: Int,
+        @Json(name = "sdpMLineIndex") val sdpMLineIndex: Int = 0,
         /**
          * Required. The SDP 'a' line of the candidate.
          */
-        @Json(name = "candidate") val candidate: String
+        @Json(name = "candidate") val candidate: String? = null
 )

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/call/model/MxCallImpl.kt

@@ -105,6 +105,7 @@ internal class MxCallImpl(
     }
 
     override fun sendLocalIceCandidates(candidates: List<CallCandidate>) {
+        Timber.v("Send local ice canditates $callId: $candidates")
         CallCandidatesContent(
                 callId = callId,
                 partyId = ourPartyId,

vector/src/main/java/im/vector/app/features/call/webrtc/WebRtcCall.kt

@@ -729,6 +729,9 @@ class WebRtcCall(val mxCall: MxCall,
     fun onCallIceCandidateReceived(iceCandidatesContent: CallCandidatesContent) {
         GlobalScope.launch(dispatcher) {
             iceCandidatesContent.candidates.forEach {
+                if (it.sdpMid.isNullOrEmpty() || it.candidate.isNullOrEmpty()) {
+                    return@forEach
+                }
                 Timber.v("## VOIP onCallIceCandidateReceived for call ${mxCall.callId} sdp: ${it.candidate}")
                 val iceCandidate = IceCandidate(it.sdpMid, it.sdpMLineIndex, it.candidate)
                 remoteCandidateSource.onNext(iceCandidate)