基于HTTP PHP文件下载类.rar（很好很实用哦）

<?PHP /** @author Nguyen Quoc Bao <quocbao.coder@gmail.com> @version 1.3 @desc A simple object for processing download operation , support section downloading Please send me an email if you find some bug or it doesn't work with download manager. I've tested it with - Reget - FDM - FlashGet - GetRight - DAP @copyright It's free as long as you keep this header . @example 1: File Download $object = new downloader; $object->set_byfile($filename); //Download from a file $object->use_resume = true; //Enable Resume Mode $object->download(); //Download File 2: Data Download $object = new downloader; $object->set_bydata($data); //Download from php data $object->use_resume = true; //Enable Resume Mode $object->set_filename($filename); //Set download name $object->set_mime($mime); //File MIME (Default: application/otect-stream) $object->download(); //Download File 3: Manual Download $object = new downloader; $object->set_filename($filename); $object->download_ex($size); //output your data here , remember to use $this->seek_start and $this->seek_end value :) **/ class httpdownload { var $data = null; var $data_len = 0; var $data_mod = 0; var $data_type = 0; var $data_section = 0; //section download /** * @var ObjectHandler **/ var $handler = array('auth' => null); var $use_resume = true; var $use_autoexit = false; var $use_auth = false; var $filename = null; var $mime = null; var $bufsize = 2048; var $seek_start = 0; var $seek_end = -1; /** * Total bandwidth has been used for this download * @var int */ var $bandwidth = 0; /** * Speed limit * @var float */ var $speed = 0; /*------------------- | Download Function | -------------------*/ /** * Check authentication and get seek position * @return bool **/ function initialize() { global $HTTP_SERVER_VARS; if ($this->use_auth) //use authentication { if (!$this->_auth()) //no authentication { header('WWW-Authenticate: Basic realm="Please enter your username and password"'); header('HTTP/1.0 401 Unauthorized'); header('status: 401 Unauthorized'); if ($this->use_autoexit) exit(); return false; } } if ($this->mime == null) $this->mime = "application/octet-stream"; //default mime if (isset($_SERVER['HTTP_RANGE']) || isset($HTTP_SERVER_VARS['HTTP_RANGE'])) { if (isset($HTTP_SERVER_VARS['HTTP_RANGE'])) $seek_range = substr($HTTP_SERVER_VARS['HTTP_RANGE'] , strlen('bytes=')); else $seek_range = substr($_SERVER['HTTP_RANGE'] , strlen('bytes=')); $range = explode('-',$seek_range); if ($range[0] > 0) { $this->seek_start = intval($range[0]); } if ($range[1] > 0) $this->seek_end = intval($range[1]); else $this->seek_end = -1; if (!$this->use_resume) { $this->seek_start = 0; //header("HTTP/1.0 404 Bad Request"); //header("Status: 400 Bad Request"); //exit; //return false; } else { $this->data_section = 1; } } else { $this->seek_start = 0; $this->seek_end = -1; } return true; } /** * Send download information header **/ function header($size,$seek_start=null,$seek_end=null) { header('Content-type: ' . $this->mime); header('Content-Disposition: attachment; filename="' . $this->filename . '"'); header('Last-Modified: ' . date('D, d M Y H:i:s \G\M\T' , $this->data_mod)); if ($this->data_section && $this->use_resume) { header("HTTP/1.0 206 Partial Content"); header("Status: 206 Partial Content"); header('Accept-Ranges: bytes'); header("Content-Range: bytes $seek_start-$seek_end/$size"); header("Content-Length: " . ($seek_end - $seek_start + 1)); } else { header("Content-Length: $size"); } } function download_ex($size) { if (!$this->initialize()) return false; ignore_user_abort(true); //Use seek end here if ($this->seek_start > ($size - 1)) $this->seek_start = 0; if ($this->seek_end <= 0) $this->seek_end = $size - 1; $this->header($size,$seek,$this->seek_end); $this->data_mod = time(); return true; } /** * Start download * @return bool **/ function download() { if (!$this->initialize()) return false; $seek = $this->seek_start; $speed = $this->speed; $bufsize = $this->bufsize; $packet = 1; //do some clean up @ob_end_clean(); $old_status = ignore_user_abort(true); @set_time_limit(0); $this->bandwidth = 0; $size = $this->data_len; if ($this->data_type == 0) //download from a file { $size = filesize($this->data); if ($seek > ($size - 1)) $seek = 0; if ($this->filename == null) $this->filename = basename($this->data); $res = fopen($this->data,'rb'); if ($seek) fseek($res , $seek); if ($this->seek_end < $seek) $this->seek_end = $size - 1; $this->header($size,$seek,$this->seek_end); //always use the last seek $size = $this->seek_end - $seek + 1; while (!(connection_aborted() || connection_status() == 1) && $size > 0) { if ($size < $bufsize) { echo fread($res , $size); $this->bandwidth += $size; } else { echo fread($res , $bufsize); $this->bandwidth += $bufsize; } $size -= $bufsize; flush(); if ($speed > 0 && ($this->bandwidth > $speed*$packet*1024)) { sleep(1); $packet++; } } fclose($res); } elseif ($this->data_type == 1) //download from a string { if ($seek > ($size - 1)) $seek = 0; if ($this->seek_end < $seek) $this->seek_end = $this->data_len - 1; $this->data = substr($this->data , $seek , $this->seek_end - $seek + 1); if ($this->filename == null) $this->filename = time(); $size = strlen($this->data); $this->header($this->data_len,$seek,$this->seek_end); while (!connection_aborted() && $size > 0) { if ($size < $bufsize) { $this->bandwidth += $size; } else {