@twilio/voice-sdk/lib/twilio/rtc/rtcpc.ts

Twilio's JavaScript Voice SDK

// @ts-nocheck
// tslint:disable only-arrow-functions
/* global webkitRTCPeerConnection, mozRTCPeerConnection, mozRTCSessionDescription, mozRTCIceCandidate */

import Log from '../log';
import * as util from '../util';
import { setCodecPreferences, setMaxAverageBitrate } from './sdp';

function RTCPC(options: { RTCPeerConnection?: any }) {
  this.log = new Log('RTCPC');

  if (typeof window === 'undefined') {
    this.log.info('No RTCPeerConnection implementation available. The window object was not found.');
    return;
  }

  if (options && options.RTCPeerConnection) {
    this.RTCPeerConnection = options.RTCPeerConnection;
  } else if (typeof window.RTCPeerConnection === 'function') {
    this.RTCPeerConnection = window.RTCPeerConnection;
  } else if (typeof window.webkitRTCPeerConnection === 'function') {
    this.RTCPeerConnection = webkitRTCPeerConnection;
  } else if (typeof window.mozRTCPeerConnection === 'function') {
    this.RTCPeerConnection = mozRTCPeerConnection;
    window.RTCSessionDescription = mozRTCSessionDescription;
    window.RTCIceCandidate = mozRTCIceCandidate;
  } else {
    this.log.info('No RTCPeerConnection implementation available');
  }
}

RTCPC.prototype.create = function(rtcConfiguration) {
  this.pc = new this.RTCPeerConnection(rtcConfiguration);
};
RTCPC.prototype.createModernConstraints = c => {
  // createOffer differs between Chrome 23 and Chrome 24+.
  // See https://groups.google.com/forum/?fromgroups=#!topic/discuss-webrtc/JBDZtrMumyU
  // Unfortunately I haven't figured out a way to detect which format
  // is required ahead of time, so we'll first try the old way, and
  // if we get an exception, then we'll try the new way.
  if (typeof c === 'undefined') {
    return null;
  }
  // NOTE(mroberts): As of Chrome 38, Chrome still appears to expect
  // constraints under the 'mandatory' key, and with the first letter of each
  // constraint capitalized. Firefox, on the other hand, has deprecated the
  // 'mandatory' key and does not expect the first letter of each constraint
  // capitalized.
  const nc = Object.assign({}, c);
  if (typeof webkitRTCPeerConnection !== 'undefined' && !util.isLegacyEdge()) {
    nc.mandatory = {};
    if (typeof c.audio !== 'undefined') {
      nc.mandatory.OfferToReceiveAudio = c.audio;
    }
    if (typeof c.video !== 'undefined') {
      nc.mandatory.OfferToReceiveVideo = c.video;
    }
  } else {
    if (typeof c.audio !== 'undefined') {
      nc.offerToReceiveAudio = c.audio;
    }
    if (typeof c.video !== 'undefined') {
      nc.offerToReceiveVideo = c.video;
    }
  }

  delete nc.audio;
  delete nc.video;

  return nc;
};
RTCPC.prototype.createOffer = function(maxAverageBitrate, constraints, onSuccess, onError) {
  constraints = this.createModernConstraints(constraints);
  return promisifyCreate(this.pc.createOffer, this.pc)(constraints).then(offer => {
    if (!this.pc) { return Promise.resolve(); }

    const sdp = setMaxAverageBitrate(offer.sdp, maxAverageBitrate);

    return promisifySet(this.pc.setLocalDescription, this.pc)(new RTCSessionDescription({
      sdp,
      type: 'offer',
    }));
  }).then(onSuccess, onError);
};
RTCPC.prototype.createAnswer = function(maxAverageBitrate, constraints, onSuccess, onError) {
  constraints = this.createModernConstraints(constraints);
  return promisifyCreate(this.pc.createAnswer, this.pc)(constraints).then(answer => {
    if (!this.pc) { return Promise.resolve(); }
    const sdp = setMaxAverageBitrate(answer.sdp, maxAverageBitrate);

    return promisifySet(this.pc.setLocalDescription, this.pc)(new RTCSessionDescription({
      sdp,
      type: 'answer',
    }));
  }).then(onSuccess, onError);
};
RTCPC.prototype.processSDP = function(maxAverageBitrate, codecPreferences, sdp, constraints, onSuccess, onError) {
  sdp = setCodecPreferences(sdp, codecPreferences);
  const desc = new RTCSessionDescription({ sdp, type: 'offer' });
  return promisifySet(this.pc.setRemoteDescription, this.pc)(desc).then(() => {
    this.createAnswer(maxAverageBitrate, constraints, onSuccess, onError);
  });
};
RTCPC.prototype.getSDP = function() {
  return this.pc.localDescription.sdp;
};
RTCPC.prototype.processAnswer = function(codecPreferences, sdp, onSuccess, onError) {
  if (!this.pc) { return Promise.resolve(); }
  sdp = setCodecPreferences(sdp, codecPreferences);

  return promisifySet(this.pc.setRemoteDescription, this.pc)(
    new RTCSessionDescription({ sdp, type: 'answer' }),
  ).then(onSuccess, onError);
};
/* NOTE(mroberts): Firefox 18 through 21 include a `mozRTCPeerConnection`
   object, but attempting to instantiate it will throw the error

       Error: PeerConnection not enabled (did you set the pref?)

   unless the `media.peerconnection.enabled` pref is enabled. So we need to test
   if we can actually instantiate `mozRTCPeerConnection`; however, if the user
   *has* enabled `media.peerconnection.enabled`, we need to perform the same
   test that we use to detect Firefox 24 and above, namely:

       typeof (new mozRTCPeerConnection()).getLocalStreams === 'function'

    NOTE(rrowland): We no longer support Legacy Edge as of Sep 1, 2020.
*/
RTCPC.test = () => {
  if (typeof navigator === 'object') {
    const getUserMedia = (navigator.mediaDevices && navigator.mediaDevices.getUserMedia)
      || navigator.webkitGetUserMedia
      || navigator.mozGetUserMedia
      || navigator.getUserMedia;

    if (util.isLegacyEdge(navigator)) {
      return false;
    }

    if (getUserMedia && typeof window.RTCPeerConnection === 'function') {
      return true;
    } else if (getUserMedia && typeof window.webkitRTCPeerConnection === 'function') {
      return true;
    } else if (getUserMedia && typeof window.mozRTCPeerConnection === 'function') {
      try {
        const test = new window.mozRTCPeerConnection();
        if (typeof test.getLocalStreams !== 'function') {
          return false;
        }
      } catch (e) {
        return false;
      }
      return true;
    } else if (typeof RTCIceGatherer !== 'undefined') {
      return true;
    }
  }

  return false;
};

function promisify(fn, ctx, areCallbacksFirst, checkRval) {
  return function() {
    const args = Array.prototype.slice.call(arguments);

    return new Promise(resolve => {
      const returnValue = fn.apply(ctx, args);
      if (!checkRval) {
        resolve(returnValue);
        return;
      }
      if (typeof returnValue === 'object' && typeof returnValue.then === 'function') {
        resolve(returnValue);
      } else {
        throw new Error();
      }
    }).catch(() => new Promise((resolve, reject) => {
      fn.apply(ctx, areCallbacksFirst
        ? [resolve, reject].concat(args)
        : args.concat([resolve, reject]));
    }));
  };
}

function promisifyCreate(fn, ctx) {
  return promisify(fn, ctx, true, true);
}

function promisifySet(fn, ctx) {
  return promisify(fn, ctx, false, false);
}

export default RTCPC;