php支持断点续传、分块下载的类

本文是为大家分享php支持断点续传、分块下载的类，供大家参考，具体内容如下

 '*
  static function parse_url($url) {
    $url_info = parse_url($url);
    if (!$url_info['host']) {
      return false;
    }
    $url_info['port']  = $url_info['port'] ? $url_info['host'] : 80;
    $url_info['request'] = $url_info['path'] . ($url_info['query'] ? '?' . $url_info['query'] : '');
    return $url_info;
  }
 
  
  static function download_content($host, $port, $url_path, $save_file, $content_length, $range_start, $speed, &$headers, $timeout) {
    $request = self::build_header('GET', $url_path, $headers, $range_start);
    $fsocket = @fsockopen($host, $port, $errno, $errstr, $timeout);
    stream_set_blocking($fsocket, TRUE);
    stream_set_timeout($fsocket, $timeout);
    fwrite($fsocket, $request);
    $status = stream_get_meta_data($fsocket);
    if ($status['timed_out']) {
      throw new Exception('Socket Connect Timeout');
    }
    $is_header_end = 0;
    $total_size  = $range_start;
    $file_fp    = fopen($save_file, 'a+');
    while (!feof($fsocket)) {
      if (!$is_header_end) {
 $line = @fgets($fsocket);
 if (in_array($line, array("n", "rn"))) {
   $is_header_end = 1;
 }
 continue;
      }
      $resp    = fread($fsocket, $speed);
      $read_length = strlen($resp);
      if ($resp === false || $content_length < $total_size + $read_length) {
 fclose($fsocket);
 fclose($file_fp);
 throw new Exception('Socket I/O Error Or File Was Changed');
      }
      $total_size += $read_length;
      fputs($file_fp, $resp);
      // check file end
      if ($content_length == $total_size) {
 break;
      }
      sleep(1);
      // for test
      //break;
    }
    fclose($fsocket);
    fclose($file_fp);
    return true;
 
  }
 
  
  static function get_content_size($host, $port, $url_path, &$headers, $timeout) {
    $request = self::build_header('HEAD', $url_path, $headers);
    $fsocket = @fsockopen($host, $port, $errno, $errstr, $timeout);
    stream_set_blocking($fsocket, TRUE);
    stream_set_timeout($fsocket, $timeout);
    fwrite($fsocket, $request);
    $status = stream_get_meta_data($fsocket);
    $length = 0;
    if ($status['timed_out']) {
      return 0;
    }
    while (!feof($fsocket)) {
      $line = @fgets($fsocket);
      if (in_array($line, array("n", "rn"))) {
 break;
      }
      $line = strtolower($line);
      // get location
      if (substr($line, 0, 9) == 'location:') {
 $location = trim(substr($line, 9));
 $url_info = self::parse_url($location);
 if (!$url_info['host']) {
   return 0;
 }
 fclose($fsocket);
 return self::get_content_size($url_info['host'], $url_info['port'], $url_info['request'], $headers, $timeout);
      }
      // get content length
      if (strpos($line, 'content-length:') !== false) {
 list(, $length) = explode('content-length:', $line);
 $length = (int)trim($length);
      }
    }
    fclose($fsocket);
    return $length;
 
  }
 
  
  static function build_header($action, $url_path, &$headers, $range_start = -1) {
    $out = $action . " {$url_path} HTTP/1.0rn";
    foreach ($headers as $hkey => $hval) {
      $out .= $hkey . ': ' . $hval . "rn";
    }
    if ($range_start > -1) {
      $out .= "Accept-Ranges: bytesrn";
      $out .= "Range: bytes={$range_start}-rn";
    }
    $out .= "rn";
 
    return $out;
  }
}
 
 
#use age

?>

以上就是本文的全部内容，希望对大家的学习有所帮助。