<?php /** * User: djunny * Date: 2016-04-29 * Time: 17:18 * Mail: 199962760@qq.com * 支持斷點下載的類 */class downloader {   /**   * download file to local path   *   * @param    $url   * @param    $save_file   * @param int  $speed   * @param array $headers   * @param int  $timeout   * @return bool   * @throws Exception   */  static function get($url, $save_file, $speed = 10240, $headers = array(), $timeout = 10) {    $url_info = self::parse_url($url);    if (!$url_info['host']) {      throw new Exception('Url is Invalid');    }     // default header    $def_headers = array(      'Accept'     => '*/*',      'User-Agent'   => 'Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0)',      'Accept-Encoding' => 'gzip, deflate',      'Host'      => $url_info['host'],      'Connection'   => 'Close',      'Accept-Language' => 'zh-cn',    );     // merge heade    $headers = array_merge($def_headers, $headers);    // get content length    $content_length = self::get_content_size($url_info['host'], $url_info['port'], $url_info['request'], $headers, $timeout);     // content length not exist    if (!$content_length) {      throw new Exception('Content-Length is Not Exists');    }    // get exists length    $exists_length = is_file($save_file) ? filesize($save_file) : 0;    // get tmp data file    $data_file = $save_file . '.data';    // get tmp data    $exists_data = is_file($data_file) ? json_decode(file_get_contents($data_file), 1) : array();    // check file is valid    if ($exists_length == $content_length) {      $exists_data && @unlink($data_file);      return true;    }    // check file is expire    if ($exists_data['length'] != $content_length || $exists_length > $content_length) {      $exists_data = array(        'length' => $content_length,      );    }    // write exists data    file_put_contents($data_file, json_encode($exists_data));     try {      $download_status = self::download_content($url_info['host'], $url_info['port'], $url_info['request'], $save_file, $content_length, $exists_length, $speed, $headers, $timeout);      if ($download_status) {        @unlink($data_file);      }    } catch (Exception $e) {      throw new Exception($e->getMessage());    }    return true;  }   /**   * parse url   *   * @param $url   * @return bool|mixed   */  static function parse_url($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;  }   /**   * download content by chunk   *   * @param $host   * @param $port   * @param $url_path   * @param $headers   * @param $timeout   */  static function download_content($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", "/r/n"))) {          $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;   }   /**   * get content length   *   * @param $host   * @param $port   * @param $url_path   * @param $headers   * @param $timeout   * @return int   */  static function get_content_size($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", "/r/n"))) {        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;   }   /**   * build header for socket   *   * @param   $action   * @param   $url_path   * @param   $headers   * @param int $range_start   * @return string   */  static function build_header($action, $url_path, &$headers, $range_start = -1) {    $out = $action . " {$url_path} HTTP/1.0/r/n";    foreach ($headers as $hkey => $hval) {      $out .= $hkey . ': ' . $hval . "/r/n";    }    if ($range_start > -1) {      $out .= "Accept-Ranges: bytes/r/n";      $out .= "Range: bytes={$range_start}-/r/n";    }    $out .= "/r/n";     return $out;  }}  #use age/*try {  if (downloader::get('http://dzs.aqtxt.com/files/11/23636/201604230358308081.rar', 'test.rar')) {    //todo    echo 'Download Succ';  }} catch (Exception $e) {  echo 'Download Failed';}*/?>