Merge pull request #1929 from matrix-org/robertlong/datachannels

Add WebRTC DataChannels to MatrixCall

src/webrtc/call.ts

@@ -128,7 +128,9 @@ export enum CallEvent {
 
     AssertedIdentityChanged = 'asserted_identity_changed',
 
-    LengthChanged = 'length_changed'
+    LengthChanged = 'length_changed',
+
+    DataChannel = 'datachannel',
 }
 
 export enum CallErrorCode {
@@ -342,6 +344,18 @@ export class MatrixCall extends EventEmitter {
         await this.placeCall(true, true);
     }
 
+    /**
+     * Create a datachannel using this call's peer connection.
+     * @param label A human readable label for this datachannel
+     * @param options An object providing configuration options for the data channel.
+     */
+    public createDataChannel(label: string, options: RTCDataChannelInit) {
+        const dataChannel = this.peerConn.createDataChannel(label, options);
+        this.emit(CallEvent.DataChannel, dataChannel);
+        logger.debug("created data channel");
+        return dataChannel;
+    }
+
     public getOpponentMember(): RoomMember {
         return this.opponentMember;
     }
@@ -1495,6 +1509,10 @@ export class MatrixCall extends EventEmitter {
         stream.addEventListener("removetrack", () => this.deleteFeedByStream(stream));
     };
 
+    private onDataChannel = (ev: RTCDataChannelEvent): void => {
+        this.emit(CallEvent.DataChannel, ev.channel);
+    };
+
     /**
      * This method removes all video/rtx codecs from screensharing video
      * transceivers. This is necessary since they can cause problems. Without
@@ -1866,6 +1884,7 @@ export class MatrixCall extends EventEmitter {
         pc.addEventListener('icegatheringstatechange', this.onIceGatheringStateChange);
         pc.addEventListener('track', this.onTrack);
         pc.addEventListener('negotiationneeded', this.onNegotiationNeeded);
+        pc.addEventListener('datachannel', this.onDataChannel);
 
         return pc;
     }