Share a super handy PHP header download function

  This article is mainly for you to share a super good PHP header download function, need friends can refer to the following

The code is as follows: <?php/**  * send file  *  * @author: Legend (legendsky@hotmail.com)  * @link: http://www.ugia.cn/ ? p=109  * @description: Send file to client  * @version: 1.0  *  * @param string   $fileName &nbs P     file name or path  * @param string   $fancyName     Custom file name, NULL to use filename  * @param boolean &N BSP; $forceDownload whether to force download  * @param integer   $speedLimit     speed limit, in bytes, 0 is unrestricted, Windows Server is not supported  * @param string   $ $contentType   file type, default to Application/octet-stream  *  * @return Boolean  */ function SendFile ($fileName, $fancyName = ', $forceDownload = true, $speedLimit = 0, $contentType = ') {    I F (!is_readable ($fileName))     {        header ("http/1.1 404 Not Found");     &N Bsp   return false;    }       $FILESTAT = stat ($fileName);     $lastModified = $fileStat [' Mtime '];   &NBSP   $MD 5 = MD5 ($fileStat [' Mtime ']. " ='. $fileStat [' ino ']. ' ='. $fileStat [' size ']);     $etag = ' "'. $MD 5. '-' . CRC32 ($MD 5). '"';       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 ']) >= $lastModified)     {        Header ("http/1.1 304 not Modified");   &nbs P     return true;    }       if (isset ($_server[' http_if_unmodified_since ')) && strtotime ($_server[' Http_if_unmodified_since '] < $lastModified)     {        http/1.1 header ("304 Not modif IED ");         return true;    }       if (isset ($_server[' Http_if_none_match ')) &&  $_server[' Http_if_none_ MATCH '] = = $etag)     {  &NBsp     Header ("http/1.1 304 not Modified");         return true;    }       if ($fancyName = = ")             $fancyName = Basena Me ($fileName);    }       if ($contentType = = ")     {        $contentType = ' A Pplication/octet-stream ';    }       $fileSize = $fileStat [' Size '];          $contentLength = $fileSize;     $isPartial = false;       if (isset ($_server[' Http_range '))     {        if (Preg_match ('/^byte S= (d*)-(d*) $/', $_server[' Http_range '], $matches))         {                $startPos = $matches [1];             $endPos = $matches [2];               if ($startPos = = ' && $endPos = = ')   &NBSp         {                return false;       & nbsp    }               if ($startPos = = ")           & nbsp {                $startPos = $fileSize-$endPos;         &NB Sp       $endPos = $fileSize-1;                         else if ($endPos = = ")   &NBSP ;         {                $endPos = $fileSize-1;   &nbs P        }               $startPos = $startPos < 0? 0: $startPos;             $endPos = $endPos > $fileSize-1? $fileSize-1: $endPos;               $length = $endPos-$startPos + 1; &nbsP             if ($length < 0)             {    &N Bsp           return false;                           $contentLength = $length;             $isPartial = true;        }     {     //Send headers     if ($isPartial)   &N Bsp {        header (' http/1.1 206 Partial Content ');         header ("Content-range:b Ytes $startPos-$endPos/$fileSize ");      }     Else     {        Header ("http/1.1 OK");   &N Bsp     $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:attachme nt Filename= "'. Rawurlencode ($fancyName). //Chinese characters automatically convert to URL code   header (' content-disposition:attachment; Filename= "'. $fancyName. '"');    }       header ("content-transfer-encoding:binary");       $bufferSize = 2048;       if ($speedLimit!= 0)     {        $packetTime = Floor ($bufferSize * 1 000000/$speedLimit);    }       $bytesSent = 0;     $FP = fopen ($fileName, "RB");     fseek ($fp, $startPos);      //fpassthru ($FP);       while ($bytesSent < $contentLength &&!feof ($fp) && connection_status () = = 0) &nb Sp   {&nbsP       if ($speedLimit!= 0)                     list ($u SEC, $sec) = Explode ("", Microtime ());              $outputTimeStart = ((float) $usec + (float) $sec);        }           $readBufferSize = $contentLength-$bytesSent < $buffe Rsize? $contentLength-$bytesSent: $bufferSize;         $buffer = Fread ($fp, $readBufferSize);                   $buffer Echo;           Ob_flush ();         flush ();           $bytesSent + + $readBufferSize;           if ($speedLimit!= 0)         {            List ($usec, $sec) = Explode ("", Microtime ());              $OUTPUTTIMEEND = ((f Loat) $usec + (float) $sec);              $useTime = ((float) $outputTimeEnd-(float) $outputTimeStart) * 1000000;             $sleepTime = round ($packetTime-$useTime);             if ($sleepTime > 0)             {                usleep ($sleepTime);                     {   }        &NBSP ;   return true; }  ?>