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PHP支持断点续传,分块下载的类

大家讲道理
Lepaskan: 2016-11-08 13:28:06
asal
1214 orang telah melayarinya

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<?php

  

/**

 * 支持断点下载的类

 */

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[&#39;host&#39;]) {

            throw new Exception(&#39;Url is Invalid&#39;);

        }

  

        // default header

        $def_headers = array(

            &#39;Accept&#39;          => &#39;*/*&#39;,

            &#39;User-Agent&#39;      => &#39;Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0)&#39;,

            &#39;Accept-Encoding&#39; => &#39;gzip, deflate&#39;,

            &#39;Host&#39;            => $url_info[&#39;host&#39;],

            &#39;Connection&#39;      => &#39;Close&#39;,

            &#39;Accept-Language&#39; => &#39;zh-cn&#39;,

        );

  

        // merge heade

        $headers = array_merge($def_headers, $headers);

        // get content length

        $content_length = self::get_content_size($url_info[&#39;host&#39;], $url_info[&#39;port&#39;], $url_info[&#39;request&#39;], $headers, $timeout);

  

        // content length not exist

        if (!$content_length) {

            throw new Exception(&#39;Content-Length is Not Exists&#39;);

        }

        // get exists length

        $exists_length = is_file($save_file) ? filesize($save_file) : 0;

        // get tmp data file

        $data_file = $save_file . &#39;.data&#39;;

        // 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[&#39;length&#39;] != $content_length || $exists_length > $content_length) {

            $exists_data = array(

                &#39;length&#39; => $content_length,

            );

        }

        // write exists data

        file_put_contents($data_file, json_encode($exists_data));

  

        try {

            $download_status = self::download_content($url_info[&#39;host&#39;], $url_info[&#39;port&#39;], $url_info[&#39;request&#39;], $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[&#39;host&#39;]) {

            return false;

        }

        $url_info[&#39;port&#39;]    = $url_info[&#39;port&#39;] ? $url_info[&#39;host&#39;] : 80;

        $url_info[&#39;request&#39;] = $url_info[&#39;path&#39;] . ($url_info[&#39;query&#39;] ? &#39;?&#39; . $url_info[&#39;query&#39;] : &#39;&#39;);

        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(&#39;GET&#39;, $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[&#39;timed_out&#39;]) {

            throw new Exception(&#39;Socket Connect Timeout&#39;);

        }

        $is_header_end = 0;

        $total_size    = $range_start;

        $file_fp       = fopen($save_file, &#39;a+&#39;);

        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(&#39;Socket I/O Error Or File Was Changed&#39;);

            }

            $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(&#39;HEAD&#39;, $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[&#39;timed_out&#39;]) {

            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) == &#39;location:&#39;) {

                $location = trim(substr($line, 9));

                $url_info = self::parse_url($location);

                if (!$url_info[&#39;host&#39;]) {

                    return 0;

                }

                fclose($fsocket);

                return self::get_content_size($url_info[&#39;host&#39;], $url_info[&#39;port&#39;], $url_info[&#39;request&#39;], $headers, $timeout);

            }

            // get content length

            if (strpos($line, &#39;content-length:&#39;) !== false) {

                list(, $length) = explode(&#39;content-length:&#39;, $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 . &#39;: &#39; . $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(&#39;http://dzs.aqtxt.com/files/11/23636/201604230358308081.rar&#39;, &#39;test.rar&#39;)) {

        //todo

        echo &#39;Download Succ&#39;;

    }

} catch (Exception $e) {

    echo &#39;Download Failed&#39;;

}

*/

?>

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