v20230122
Parameter: $url 
Output: filesize
function get_remote_file_info($url) {
  $ch = curl_init($url);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
  curl_setopt($ch, CURLOPT_HEADER, TRUE);
  curl_setopt($ch, CURLOPT_NOBODY, TRUE);
  $data = curl_exec($ch);
  $fileSize = curl_getinfo($ch, CURLINFO_CONTENT_LENGTH_DOWNLOAD);
  $httpResponseCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
  curl_close($ch);
  return [
    'fileExists' => (int) $httpResponseCode == 200,
    'fileSize' => (int) $fileSize
  ];
}