php多线程下载远程多个文件示例方法

function remote($urls, $name = '', $path = '', $dir = './images/') {
 if (!is_array($urls) or count($urls) == 0) {
  return false;
 }
 dmkdir($dir);
 $curl = $text = array();
 foreach($urls as $k => $v) {
  if (!empty($v) && preg_match("~^http~i", $v)) {
   $nurl[$k] = trim(str_replace(' ', "%20", $v));
   $curl[$k] = curl_init($nurl[$k]);
   curl_setopt($curl[$k], CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4 );
   curl_setopt($curl[$k], CURLOPT_RETURNTRANSFER, 1);
   curl_setopt($curl[$k], CURLOPT_HEADER, 0);
   curl_setopt($curl[$k], CURLOPT_CONNECTTIMEOUT, 20);
   if(!isset($handle)){
    $handle = curl_multi_init();
   }
   curl_multi_add_handle($handle, $curl[$k]);
  }
  continue ;
 }
 $active = null;
 do{
  $mrc = @curl_multi_exec($handle, $active);
 } while ($mrc == CURLM_CALL_MULTI_PERFORM);
 while ($active && $mrc == CURLM_OK) {
  if (curl_multi_select($handle) != -1) {
   do {
    $mrc = curl_multi_exec($handle, $active);
   } while ($mrc == CURLM_CALL_MULTI_PERFORM);
  }
 }
 foreach ($curl as $k => $v) {
   if (curl_error($curl[$k]) == "") {
    if ($k == 0) {
     $fname[$k] = strtolower($name . '.' . pathinfo($urls[$k], PATHINFO_EXTENSION));
    } else {
     $fname[$k] = strtolower($name . '_' . $k . '.' . pathinfo($urls[$k], PATHINFO_EXTENSION));
    }
    $text[$k] = (string) curl_multi_getcontent($curl[$k]);
    $filedir[$k] = $dir.'/' . $fname[$k];
   if (file_put_contents($filedir[$k], $text[$k])) {
    $filepath[$k] = $path . $fname[$k];
   }
  }
  curl_multi_remove_handle($handle, $curl[$k]);
  curl_close($curl[$k]);
 }
 curl_multi_close($handle);
 return $filepath;
}