分享一個超好用的php header下載函數

 這篇文章主要為大家分享一個超好用的php header下載函數,需要的朋友可以參考下

代碼如下: <?php /**  * 發送文件  *  * @author: legend([email protected])  * @link: http://www.ugia.cn/?p=109  * @description: send file to client  * @version: 1.0  *  * @param string   $fileName      文件名稱或路徑  * @param string   $fancyName     自定義的文件名,為空則使用filename  * @param boolean  $forceDownload 是否強制下載  * @param integer  $speedLimit    速度限制,單位為字節,0為不限制,不支持windows服務器  * @param string   $$contentType  文件類型,默認為application/octet-stream  *  * @return boolean  */ function sendFile($fileName, $fancyName = '', $forceDownload = true, $speedLimit = 0, $contentType = '') {     if (!is_readable($fileName))     {         header("HTTP/1.1 404 Not Found");         return false;     }       $fileStat = stat($fileName);     $lastModified = $fileStat['mtime'];       $md5 = md5($fileStat['mtime'] .'='. $fileStat['ino'] .'='. $fileStat['size']);     $etag = '"' . $md5 . '-' . crc32($md5) . '"';       header('Last-Modified: ' . gmdate("D, d M Y H:i:s", $lastModified) . ' GMT');     header("ETag: $etag");       if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) >= $lastModified)     {         header("HTTP/1.1 304 Not Modified");         return true;     }       if (isset($_SERVER['HTTP_IF_UNMODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_UNMODIFIED_SINCE']) < $lastModified)     {         header("HTTP/1.1 304 Not Modified");         return true;     }       if (isset($_SERVER['HTTP_IF_NONE_MATCH']) &&  $_SERVER['HTTP_IF_NONE_MATCH'] == $etag)     {         header("HTTP/1.1 304 Not Modified");         return true;     }       if ($fancyName == '')     {         $fancyName = basename($fileName);     }       if ($contentType == '')     {         $contentType = 'application/octet-stream';     }       $fileSize = $fileStat['size'];          $contentLength = $fileSize;     $isPartial = false;       if (isset($_SERVER['HTTP_RANGE']))     {         if (preg_match('/^bytes=(d*)-(d*)$/', $_SERVER['HTTP_RANGE'], $matches))         {                 $startPos = $matches[1];             $endPos = $matches[2];               if ($startPos == '' && $endPos == '')             {                 return false;             }               if ($startPos == '')             {                 $startPos = $fileSize - $endPos;                 $endPos = $fileSize - 1;             }             else if ($endPos == '')             {                 $endPos = $fileSize - 1;             }               $startPos = $startPos < 0 ? 0 : $startPos;             $endPos = $endPos > $fileSize - 1 ? $fileSize - 1 : $endPos;               $length = $endPos - $startPos + 1;               if ($length < 0)             {                 return false;             }               $contentLength = $length;             $isPartial = true;         }     }       // send headers     if ($isPartial)     {         header('HTTP/1.1 206 Partial Content');         header("Content-Range: bytes $startPos-$endPos/$fileSize");       }     else     {         header("HTTP/1.1 200 OK");         $startPos = 0;         $endPos = $contentLength - 1;     }       header('Pragma: cache');     header('Cache-Control: public, must-revalidate, max-age=0');     header('Accept-Ranges: bytes');     header('Content-type: ' . $contentType);     header('Content-Length: ' . $contentLength);       if ($forceDownload)     {         header('Content-Disposition: attachment; filename="' . rawurlencode($fancyName). '"');//漢字自動轉為URL編碼   header('Content-Disposition: attachment; filename="' . $fancyName. '"');     }       header("Content-Transfer-Encoding: binary");       $bufferSize = 2048;       if ($speedLimit != 0)     {         $packetTime = floor($bufferSize * 1000000 / $speedLimit);     }       $bytesSent = 0;     $fp = fopen($fileName, "rb");     fseek($fp, $startPos);       //fpassthru($fp);       while ($bytesSent < $contentLength && !feof($fp) && connection_status() == 0 )     {         if ($speedLimit != 0)         {             list($usec, $sec) = explode(" ", microtime());              $outputTimeStart = ((float)$usec + (float)$sec);         }           $readBufferSize = $contentLength - $bytesSent < $bufferSize ? $contentLength - $bytesSent : $bufferSize;         $buffer = fread($fp, $readBufferSize);                   echo $buffer;           ob_flush();         flush();           $bytesSent += $readBufferSize;           if ($speedLimit != 0)         {             list($usec, $sec) = explode(" ", microtime());              $outputTimeEnd = ((float)$usec + (float)$sec);               $useTime = ((float) $outputTimeEnd - (float) $outputTimeStart) * 1000000;             $sleepTime = round($packetTime - $useTime);             if ($sleepTime > 0)             {                 usleep($sleepTime);             }         }     }