php的一个断点续传下载实现

        $file = "我是一个路径";
        if(empty($file)){
            $this->displayJson(Ap_Constants::ERROR_EMPTY);
        }

        
        $file_name = $file['name'];
        $size = $file['size'];
        //中文需要转码
        $path = iconv('UTF-8', 'GB2312', $file['path']);
        $size = $filesize=filesize($path);

   
        $fm = @fopen ( $path, 'rb' );
        $begin = 0;
        $end = $size - 1;
         
        if (isset ( $_SERVER ['HTTP_RANGE'] )) {
            if (preg_match ( '/bytes=\h*(\d+)-(\d*)[\D.*]?/i', $_SERVER ['HTTP_RANGE'], $matches )) {
                // 读取文件，起始节点
                $begin = intval ( $matches [1] );
         
                // 读取文件，结束节点
                if (! empty ( $matches [2] )) {
                    $end = intval ( $matches [2] );
                }
            }
        }
         
        if (isset ( $_SERVER ['HTTP_RANGE'] )) {
            header ( 'HTTP/1.1 206 Partial Content' );
        } else {
            header ( 'HTTP/1.1 200 OK' );
        }
         
        Header("Content-type: application/vnd.android.package-archive");
        header ( 'Cache-Control: public, must-revalidate, max-age=0' );
        header ( 'Pragma: no-cache' );
        header ( 'Accept-Ranges: bytes' );
        header ( 'Content-Length:' . (($end - $begin) + 1) );
         
        if (isset ( $_SERVER ['HTTP_RANGE'] )) {
            header ( "Content-Range: bytes $begin-$end/$size" );
        }
         
        header ( "Content-Disposition: inline; filename=$file_name" );
        header ( "Content-Transfer-Encoding: binary" );
         
        $cur = $begin;
         
        // 定位指针
        fseek ( $fm, $begin, 0 );
        ob_clean();
        flush();
        while ( ! feof ( $fm ) && $cur <= $end && (connection_status () == 0) ) {
            print fread ( $fm, min ( 1024 * 16, ($end - $cur) + 1 ) );
            $cur += 1024 * 16;
        }
        exit(0);