class eZOwtResumableDownload {
 ...

/*!
  Downloads data from $url to $localfile
  
  This is implemented using the CURL libraries,
  which are more robust than the built in fopen
  wrappers. Also it will attempt to resume a
  previous partial download using ranged GET
  calls if needed.
  
  \return
  1 => on success
  -1 => failed to open output file for writing (permission denied?)
  -2 => failed to open remote url for reading
  -3 => failed during write to local file (disk full?)
*/
function downloadWithCurl() {
  $localfile = $this->localFileName();
  $url = $this->getFullUrl($this->url);
  
  if (eZFile::file_exists($localfile)) {
    // resume
    $resumePoint = @eZFile::filesize(
                      $localfile);
    $outputFileHandle = eZFile::fopen(
       $this->localFileName(), 'ab');
  }
  else {
    $resumePoint=0;
    $outputFileHandle = eZFile::fopen(
       $this->localFileName(), 'wb');
  }
      
  if (!$outputFileHandle) {
    return -1;
  }
  
  $this->_curlOutputFileHandle =
     $outputFileHandle;
  
  $ch = curl_init ($url);
  if (!$ch) {
    return -2;
  }
  
  
  if ($resumePoint>=$this->filesize) {
    $this->logMessage("Previous transfer is complete. No more data to download. Continuing", OWT_MESSAGE_INFO);
    return 1;
  }
  else if ($resumePoint) {
    $this->logMessage("Resuming previously aborted transfer from byte $resumePoint", OWT_MESSAGE_INFO);
    curl_setopt($ch, CURLOPT_RESUME_FROM, $resumePoint);
  }
  
  curl_setopt($ch, CURLOPT_LOW_SPEED_LIMIT,
              20); // min bytes/sec
  curl_setopt($ch,CURLOPT_LOW_SPEED_TIME,
              500); // in secs
  curl_setopt($ch,CURLOPT_FAILONERROR,1);
  curl_setopt($ch,CURLOPT_WRITEFUNCTION,
        array(&$this, "curlWriteCallback"));
  
  $this->_downloadStartStamp=time(); 
  $this->_downloadedBytes=$resumePoint; 
  
  $success = curl_exec($ch);
  
  if (!$success) {
    $this->logMessage('Transfer failed. Reason: '.curl_error($ch), OWT_MESSAGE_ERROR);
    return -3;
  }
  
  if ($outputFileHandle) {
    unset($this->_curlOutputFileHandle);
    fclose( $outputFileHandle );
  }
  
  return 1;
}

...

}