Fix Non UTF Characters in a MODX Resource

fixinvalidchars.snippet.php

<?php

$regex = <<<'END'
/
  (
    (?: [\x00-\x7F]                 # single-byte sequences   0xxxxxxx
    |   [\xC0-\xDF][\x80-\xBF]      # double-byte sequences   110xxxxx 10xxxxxx
    |   [\xE0-\xEF][\x80-\xBF]{2}   # triple-byte sequences   1110xxxx 10xxxxxx * 2
    |   [\xF0-\xF7][\x80-\xBF]{3}   # quadruple-byte sequence 11110xxx 10xxxxxx * 3 
    ){1,100}                        # ...one or more times
  )
| .                                 # anything else
/x
END;
$resource = $modx->getObject('modResource', 3);
if(!empty($resource)){
  $content = preg_replace($regex, '$1', $resource->get('content'));
  $resource->set('content', $content);
  if($resource->save()){
    echo "Resource Saved!";
  }
}