Auto set up Media Source for MS2Gallery by template

autoMediaSource.php

<?php
if ( $modx->event->name == 'OnDocFormSave' && $mode == modSystemEvent::MODE_NEW ) {
  switch ( $resource->get( 'template' ) ) {
    case 1:
      $properties = $modx->fromJSON( $resource->get( 'properties' ) );
      $properties[ 'ms2gallery' ] = array( 'media_source' => 2 );
      break;

    default:
      break;
  }
  $resource->set( 'properties', $modx->toJSON( $properties ) );
  $resource->save();
}