bigbluebutton-Github/bigbluebutton-html5/imports/ui/services/bbb-webrtc-sfu/screenshare-broker.js

import logger from '/imports/startup/client/logger';
import BaseBroker from '/imports/ui/services/bbb-webrtc-sfu/sfu-base-broker';
import WebRtcPeer from '/imports/ui/services/webrtc-base/peer';

const ON_ICE_CANDIDATE_MSG = 'iceCandidate';
const SUBSCRIBER_ANSWER = 'subscriberAnswer';
const SFU_COMPONENT_NAME = 'screenshare';

class ScreenshareBroker extends BaseBroker {
  constructor(
    wsUrl,
    voiceBridge,
    userId,
    internalMeetingId,
    role,
    options = {},
  ) {
    super(SFU_COMPONENT_NAME, wsUrl);
    this.voiceBridge = voiceBridge;
    this.userId = userId;
    this.internalMeetingId = internalMeetingId;
    this.role = role;
    this.ws = null;
    this.webRtcPeer = null;
    this.hasAudio = false;
    this.contentType = "camera";
    this.offering = true;
    this.signalCandidates = true;
    this.ending = false;

    // Optional parameters are:
    // userName,
    // caleeName,
    // iceServers,
    // hasAudio,
    // contentType,
    // bitrate,
    // offering,
    // mediaServer,
    // signalCandidates,
    // traceLogs
    // networkPriority
    // gatheringTimeout
    Object.assign(this, options);
  }

  _onstreamended() {
    // Flag the broker as ending; we want to abort processing start responses
    this.ending = true;
    this.onstreamended();
  }

  onstreamended() {
    // To be implemented by instantiators
  }

  async share () {
    return new Promise((resolve, reject) => {
      if (this.stream == null) {
        logger.error({
          logCode: `${this.logCodePrefix}_missing_stream`,
          extraInfo: { role: this.role, sfuComponent: this.sfuComponent },
        }, 'Screenshare broker start failed: missing stream');
        return reject(BaseBroker.assembleError(1305));
      }

      return this.openWSConnection()
        .then(this.startScreensharing.bind(this))
        .then(resolve)
        .catch(reject);
    });
  }

  view () {
    return this.openWSConnection()
      .then(this.subscribeToScreenStream.bind(this));
  }

  onWSMessage (message) {
    const parsedMessage = JSON.parse(message.data);

    switch (parsedMessage.id) {
      case 'startResponse':
        if (!this.ending && !this.started) {
          this.onRemoteDescriptionReceived(parsedMessage);
        }
        break;
      case 'playStart':
        if (!this.ending && !this.started) {
          this.onstart();
          this.started = true;
        }
        break;
      case 'stopSharing':
        this.stop();
        break;
      case 'iceCandidate':
        this.handleIceCandidate(parsedMessage.candidate);
        break;
      case 'error':
        this.handleSFUError(parsedMessage);
        break;
      case 'pong':
        break;
      default:
        logger.debug({
          logCode: `${this.logCodePrefix}_invalid_req`,
          extraInfo: {
            messageId: parsedMessage.id || 'Unknown',
            sfuComponent: this.sfuComponent,
            role: this.role,
          }
        }, `Discarded invalid SFU message`);
    }
  }

  handleSFUError (sfuResponse) {
    const { code, reason } = sfuResponse;
    const error = BaseBroker.assembleError(code, reason);

    logger.error({
      logCode: `${this.logCodePrefix}_sfu_error`,
      extraInfo: {
        errorCode: code,
        errorMessage: error.errorMessage,
        role: this.role,
        sfuComponent: this.sfuComponent,
        started: this.started,
      },
    }, `Screen sharing failed in SFU`);
    this.onerror(error);
  }

  sendLocalDescription (localDescription) {
    const message = {
      id: SUBSCRIBER_ANSWER,
      type: this.sfuComponent,
      role: this.role,
      voiceBridge: this.voiceBridge,
      callerName: this.userId,
      answer: localDescription,
    };

    this.sendMessage(message);
  }

  onRemoteDescriptionReceived (sfuResponse) {
    if (this.offering) {
      return this.processAnswer(sfuResponse);
    }

    return this.processOffer(sfuResponse);
  }

  sendStartReq(offer) {
    const message = {
      id: 'start',
      type: this.sfuComponent,
      role: this.role,
      internalMeetingId: this.internalMeetingId,
      voiceBridge: this.voiceBridge,
      userName: this.userName,
      callerName: this.userId,
      sdpOffer: offer,
      hasAudio: !!this.hasAudio,
      contentType: this.contentType,
      bitrate: this.bitrate,
      mediaServer: this.mediaServer,
    };

    this.sendMessage(message);
  }

  _handleOfferGenerationFailure(error) {
    logger.error({
      logCode: `${this.logCodePrefix}_offer_failure`,
      extraInfo: {
        errorMessage: error.name || error.message || 'Unknown error',
        role: this.role,
        sfuComponent: this.sfuComponent,
      },
    }, 'Screenshare offer generation failed');
    // 1305: "PEER_NEGOTIATION_FAILED",
    return this.onerror(error);
  }

  startScreensharing() {
    return new Promise((resolve, reject) => {
      try {
        const options = {
          onicecandidate: this.signalCandidates ? this.onIceCandidate.bind(this) : null,
          videoStream: this.stream,
          configuration: this.populatePeerConfiguration(),
          trace: this.traceLogs,
          networkPriorities: this.networkPriority ? { video: this.networkPriority } : undefined,
          gatheringTimeout: this.gatheringTimeout,
        };
        this.webRtcPeer = new WebRtcPeer('sendonly', options);
        this.webRtcPeer.iceQueue = [];
        this.webRtcPeer.start();
        this.webRtcPeer.peerConnection.onconnectionstatechange = () => {
          this.handleConnectionStateChange('screenshare');
        };

        if (this.offering) {
          this.webRtcPeer.generateOffer()
            .then(this.sendStartReq.bind(this))
            .catch(this._handleOfferGenerationFailure.bind(this));
        } else {
          this.sendStartReq();
        }

        resolve();
      } catch (error) {
        // 1305: "PEER_NEGOTIATION_FAILED",
        const normalizedError = BaseBroker.assembleError(1305);
        logger.error({
          logCode: `${this.logCodePrefix}_peer_creation_failed`,
          extraInfo: {
            errorMessage: error.name || error.message || 'Unknown error',
            errorCode: normalizedError.errorCode,
            role: this.role,
            sfuComponent: this.sfuComponent,
            started: this.started,
          },
        }, 'Screenshare peer creation failed');
        this.onerror(normalizedError);
        reject(normalizedError);
      }
    });
  }

  onIceCandidate (candidate) {
    const message = {
      id: ON_ICE_CANDIDATE_MSG,
      role: this.role,
      type: this.sfuComponent,
      voiceBridge: this.voiceBridge,
      candidate,
      callerName: this.userId,
    };

    this.sendMessage(message);
  }

  subscribeToScreenStream() {
    return new Promise((resolve, reject) => {
      try {
        const options = {
          mediaConstraints: {
            audio: !!this.hasAudio,
          },
          onicecandidate: this.signalCandidates ? this.onIceCandidate.bind(this) : null,
          configuration: this.populatePeerConfiguration(),
          trace: this.traceLogs,
          gatheringTimeout: this.gatheringTimeout,
        };

        this.webRtcPeer = new WebRtcPeer('recvonly', options);
        this.webRtcPeer.iceQueue = [];
        this.webRtcPeer.start();
        this.webRtcPeer.peerConnection.onconnectionstatechange = () => {
          this.handleConnectionStateChange('screenshare');
        };

        if (this.offering) {
          this.webRtcPeer.generateOffer()
            .then(this.sendStartReq.bind(this))
            .catch(this._handleOfferGenerationFailure.bind(this));
        } else {
          this.sendStartReq();
        }

        resolve();
      } catch (error) {
        // 1305: "PEER_NEGOTIATION_FAILED",
        const normalizedError = BaseBroker.assembleError(1305);
        logger.error({
          logCode: `${this.logCodePrefix}_peer_creation_failed`,
          extraInfo: {
            errorMessage: error.name || error.message || 'Unknown error',
            errorCode: normalizedError.errorCode,
            role: this.role,
            sfuComponent: this.sfuComponent,
            started: this.started,
          },
        }, 'Screenshare peer creation failed');
        this.onerror(normalizedError);
        reject(normalizedError);

      }
    });
  }
}

export default ScreenshareBroker;