signal-desktop/app/permissions.js

// Copyright 2018-2020 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only

// The list of permissions is here:
//   https://electronjs.org/docs/api/session#sessetpermissionrequesthandlerhandler

const PERMISSIONS = {
  // Allowed
  fullscreen: true, // required to show videos in full-screen
  notifications: true, // required to show OS notifications for new messages

  // Off by default, can be enabled by user
  media: false, // required for access to microphone and camera, used for voice notes and calling

  // Not allowed
  geolocation: false,
  midiSysex: false,
  openExternal: false, // we don't need this; we open links via 'will-navigate' event
  pointerLock: false,
};

function _createPermissionHandler(userConfig) {
  return (webContents, permission, callback, details) => {
    // We default 'media' permission to false, but the user can override that for
    // the microphone and camera.
    if (
      permission === 'media' &&
      details.mediaTypes.includes('audio') &&
      userConfig.get('mediaPermissions')
    ) {
      return callback(true);
    }
    if (
      permission === 'media' &&
      details.mediaTypes.includes('video') &&
      userConfig.get('mediaCameraPermissions')
    ) {
      return callback(true);
    }

    if (PERMISSIONS[permission]) {
      console.log(`Approving request for permission '${permission}'`);
      return callback(true);
    }

    console.log(`Denying request for permission '${permission}'`);
    return callback(false);
  };
}

function installPermissionsHandler({ session, userConfig }) {
  // Setting the permission request handler to null first forces any permissions to be
  //   requested again. Without this, revoked permissions might still be available if
  //   they've already been used successfully.
  session.defaultSession.setPermissionRequestHandler(null);

  session.defaultSession.setPermissionRequestHandler(
    _createPermissionHandler(userConfig)
  );
}

module.exports = {
  installPermissionsHandler,
};