Add new properties for getting RTPTransceivers. (#491)

Background and design: docs/design/owt_with_webrtc_apis.md

* Add new properties for getting senders and receivers.

* Property senders is not available in P2P mode.

* Add test cases.

* Move transceivers to TransportSettings.

* Fix a typo.

Author: jianjunz

docs/design/owt_with_webrtc_apis.md

@@ -9,8 +9,8 @@ OWT(Open WebRTC Toolkit) Client SDKs provide convenient APIs to create, publish,
 - Set preferred codecs.
 - Disable or enable RTX / RED / FEC.
 #### API Changes
-- A new method `getSender` will be added to `Publication`. It returns an `RTCRtpSender` for certain `Publication`.
-- A new method `getReceiver` will be added to `Subscription`. It returns an `RTCRtpReceiver` for certain `Subscription`.
+- A new member `rtpTransceivers` will be added to `TransportSettings`. It returns an array `RTCRtpReceiver`s for RTP transport.
+- A new member `transport` will be added to `Publication` and `Subscription`. Developers could get `RTPTransceiver`s from its `rtpTransceivers` property.
 - A new method `addTransceiver(DOMString trackKind, sequence<RTCRtpEncodingParameters> sendEncodings)` will be added to `ConferenceClient`. It invokes `RTCPeerConnection.addTransceiver(trackKind, {direction:inactive, sendEncodings:sendEncodings})`, returns an `RTCRtpTransceiver`. Please note that direction is `inactive` until a `publish` with return transceiver is called.
 - The second parameter of `ConferenceClient.publish` accepts an `RTCRtpTransceiver` created by `RTCPeerConnection.addTransceiver`. When this method is called, certain `RTCRtpTransceiver`'s direction is changed to `sendonly`, and its sender's `setStreams` is called with the first parameter's `mediaStream`.
 #### Server Requirements

docs/mdfiles/changelog.md

@@ -2,6 +2,8 @@ Change Log
 ==========
 # 5.1
 * When subscribe a stream in conference mode, the subscribed MediaStream or BidirectionalStream is associated with a `Owt.Conference.Subscription` instead of a `Owt.Base.RemoteStream`. The `stream` property of a RemoteStream in conference mode is always undefined, while a new property `stream` is added to `Subscription`. It allows a RemoteStream to be subscribed multiple times, as well as subscribing audio and video tracks from different streams.
+* Add a new property `transport` to `Publication` for getting `TransportSettings`.
+* Add a new property `rtpTransceivers` to `TransportSettings` and `TransportConstraints`.
 # 5.0
 * Add WebTransport support for conference mode, see [this design doc](../../design/webtransport.md) for detailed information.
 * All publications and subscriptions for the same conference use the same `PeerConnection`.

src/sdk/base/publication.js

@@ -123,7 +123,7 @@ export class PublicationSettings {
  */
 export class Publication extends EventDispatcher {
   // eslint-disable-next-line require-jsdoc
-  constructor(id, stop, getStats, mute, unmute) {
+  constructor(id, transport, stop, getStats, mute, unmute) {
     super();
     /**
      * @member {string} id
@@ -135,6 +135,18 @@ export class Publication extends EventDispatcher {
       writable: false,
       value: id ? id : Utils.createUuid(),
     });
+    /**
+     * @member {Owt.Base.TransportSettings} transport
+     * @instance
+     * @readonly
+     * @desc Transport settings for the publication.
+     * @memberof Owt.Base.Publication
+     */
+    Object.defineProperty(this, 'transport', {
+      configurable: false,
+      writable: false,
+      value: transport,
+    });
     /**
      * @function stop
      * @instance

src/sdk/base/transport.js

@@ -56,18 +56,29 @@ export class TransportSettings {
   // eslint-disable-next-line require-jsdoc
   constructor(type, id) {
     /**
-     * @member {Array.<Owt.Base.TransportType>} type
+     * @member {Owt.Base.TransportType} type
      * @instance
-     * @memberof Owt.Base.TransportConstraints
+     * @memberof Owt.Base.TransportSettings
      * @desc Transport type for publication and subscription.
      */
     this.type = type;
     /**
      * @member {string} id
      * @instance
-     * @memberof Owt.Base.TransportConstraints
+     * @memberof Owt.Base.TransportSettings
      * @desc Transport ID.
      */
     this.id = id;
+
+    /**
+     * @member {?Array.<RTCRtpTransceiver>} rtpTransceivers
+     * @instance
+     * @memberof Owt.Base.TransportSettings
+     * @desc A list of RTCRtpTransceiver associated with the publication or
+     * subscription. It's only available in conference mode when TransportType
+     * is webrtc.
+     * @see {@link https://w3c.github.io/webrtc-pc/#rtcrtptransceiver-interface|RTCRtpTransceiver Interface of WebRTC 1.0}.
+     */
+    this.rtpTransceivers = undefined;
   }
 }

src/sdk/conference/channel.js

@@ -21,6 +21,7 @@ import {Subscription} from './subscription.js';
 import {ConferenceError} from './error.js';
 import * as Utils from '../base/utils.js';
 import * as SdpUtils from '../base/sdputils.js';
+import {TransportSettings, TransportType} from '../base/transport.js';
 
 /**
  * @class ConferencePeerConnectionChannel
@@ -876,25 +877,40 @@ export class ConferencePeerConnectionChannel extends EventDispatcher {
     const internalId = this._reverseIdMap.get(sessionId);
     if (this._subscribePromises.has(internalId)) {
       const mediaStream = this._remoteMediaStreams.get(sessionId);
-      const subscription = new Subscription(sessionId, mediaStream, () => {
-        this._unsubscribe(internalId);
-      }, () => this._getStats(),
-      (trackKind) => this._muteOrUnmute(sessionId, true, false, trackKind),
-      (trackKind) => this._muteOrUnmute(sessionId, false, false, trackKind),
-      (options) => this._applyOptions(sessionId, options));
+      const transportSettings =
+          new TransportSettings(TransportType.WEBRTC, this._id);
+      transportSettings.rtpTransceivers =
+          this._subscribeTransceivers.get(internalId).transceivers;
+      const subscription = new Subscription(
+          sessionId, mediaStream, transportSettings,
+          () => {
+            this._unsubscribe(internalId);
+          },
+          () => this._getStats(),
+          (trackKind) => this._muteOrUnmute(sessionId, true, false, trackKind),
+          (trackKind) => this._muteOrUnmute(sessionId, false, false, trackKind),
+          (options) => this._applyOptions(sessionId, options));
       this._subscriptions.set(sessionId, subscription);
       // Resolve subscription if mediaStream is ready.
       if (this._subscriptions.get(sessionId).stream) {
         this._subscribePromises.get(internalId).resolve(subscription);
         this._subscribePromises.delete(internalId);
       }
     } else if (this._publishPromises.has(internalId)) {
-      const publication = new Publication(sessionId, () => {
-        this._unpublish(internalId);
-        return Promise.resolve();
-      }, () => this._getStats(),
-      (trackKind) => this._muteOrUnmute(sessionId, true, true, trackKind),
-      (trackKind) => this._muteOrUnmute(sessionId, false, true, trackKind));
+      const transportSettings =
+          new TransportSettings(TransportType.WEBRTC, this._id);
+      transportSettings.transceivers =
+          this._publishTransceivers.get(internalId).transceivers;
+      const publication = new Publication(
+          sessionId,
+          transportSettings,
+          () => {
+            this._unpublish(internalId);
+            return Promise.resolve();
+          },
+          () => this._getStats(),
+          (trackKind) => this._muteOrUnmute(sessionId, true, true, trackKind),
+          (trackKind) => this._muteOrUnmute(sessionId, false, true, trackKind));
       this._publications.set(sessionId, publication);
       this._publishPromises.get(internalId).resolve(publication);
       // Do not fire publication's ended event when associated stream is ended.

src/sdk/conference/subscription.js

@@ -270,7 +270,8 @@ export class SubscriptionUpdateOptions {
  */
 export class Subscription extends EventDispatcher {
   // eslint-disable-next-line require-jsdoc
-  constructor(id, stream, stop, getStats, mute, unmute, applyOptions) {
+  constructor(
+      id, stream, transport, stop, getStats, mute, unmute, applyOptions) {
     super();
     if (!id) {
       throw new TypeError('ID cannot be null or undefined.');
@@ -298,6 +299,18 @@ export class Subscription extends EventDispatcher {
       writable: true,
       value: stream,
     });
+    /**
+     * @member {Owt.Base.TransportSettings} transport
+     * @instance
+     * @readonly
+     * @desc Transport settings for the subscription.
+     * @memberof Owt.Base.Subscription
+     */
+    Object.defineProperty(this, 'transport', {
+      configurable: false,
+      writable: false,
+      value: transport,
+    });
     /**
      * @function stop
      * @instance

src/sdk/p2p/peerconnection-channel.js

@@ -305,8 +305,9 @@ class P2PPeerConnectionChannel extends EventDispatcher {
                 (element) => element.mediaStream.id == mediaStreamId);
             const targetStream = this._publishingStreams[targetStreamIndex];
             this._publishingStreams.splice(targetStreamIndex, 1);
+            // TODO: Set transceivers for Publication.
             const publication = new Publication(
-                id, () => {
+                id, undefined, () => {
                   this._unpublish(targetStream).then(() => {
                     publication.dispatchEvent(new OwtEvent('ended'));
                   }, (err) => {

test/unit/resources/scripts/base.js

@@ -8,9 +8,9 @@ import * as MediaStreamFactoryModule from '../../../../src/sdk/base/mediastream-
 import * as StreamModule from '../../../../src/sdk/base/stream.js';
 import * as MediaFormatModule from '../../../../src/sdk/base/mediaformat.js'
 import * as SdpUtils from '../../../../src/sdk/base/sdputils.js'
+import * as PublicationModule from '../../../../src/sdk/base/publication.js'
 
 const expect = chai.expect;
-const screenSharingExtensionId = 'jniliohjdiikfjjdlpapmngebedgigjn';
 chai.use(chaiAsPromised);
 describe('Unit tests for MediaStreamFactory', function() {
   function createMediaStream(constraints, audioTracksExpected,
@@ -181,3 +181,15 @@ describe('Unit tests for SDP utils.', function() {
     done();
   });
 });
+
+describe('Unit tests for Publication.', () => {
+  it('Get senders returns all transceivers\' sender.', () => {
+    it('Get transport returns correct TransportSettings.', () => {
+      const transportSettings =
+          new TransportSettings(TransportType.WEBRTC, 'randomId');
+      const publication =
+          new PublicationModule.Publication('sessionId', transportSettings);
+      expect(publication.transport).to.equal(transportSettings);
+    });
+  });
+});

test/unit/resources/scripts/conference.js

@@ -8,9 +8,10 @@ import {ConferenceClient} from '../../../../src/sdk/conference/client.js';
 import {ConferencePeerConnectionChannel} from '../../../../src/sdk/conference/channel.js';
 import * as StreamModule from '../../../../src/sdk/base/stream.js';
 import * as EventModule from '../../../../src/sdk/base/event.js'
+import * as SubscriptionModule from '../../../../src/sdk/conference/subscription.js'
+import { TransportSettings, TransportType } from '../../../../src/sdk/base/transport.js';
 
 const expect = chai.expect;
-const screenSharingExtensionId = 'jniliohjdiikfjjdlpapmngebedgigjn';
 chai.use(chaiAsPromised);
 
 describe('Unit tests for ConferenceClient', function() {
@@ -98,4 +99,14 @@ describe('Unit tests for ConferencePeerConnectionChannel.', () => {
       }
     });
   });
+});
+
+describe('Unit tests for Subscription.', () => {
+  it('Get transport returns correct TransportSettings.', () => {
+    const transportSettings =
+        new TransportSettings(TransportType.WEBRTC, 'randomId');
+    const subscription = new SubscriptionModule.Subscription(
+        'sessionId', undefined, transportSettings);
+    expect(subscription.transport).to.equal(transportSettings);
+  });
 });