Useful PHP Header Download function

/** * Send File * * @param string $fileName file name or path * @param string $fancyName A custom file name, or null to use filename * @param boolean $forceDownload whether to force download * @param integer $speedLimit speed limit in bytes, 0 is unrestricted, Windows Server is not supported * @param string $ $contentType file type, default is Application/octet-stream * * @return Boolean */ function SendFile ($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 ']; $MD 5 = MD5 ($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"); 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 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). ' "');//kanji automatically to URL encoding Header (' content-disposition:attachment; Filename= '. $fancyName. '"'); } Header ("Content-transfer-encoding:binary"); header function Implementation file download $bufferSize = 2048; if ($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); }//Bbs.it-home.org $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); } } } return true; } ?> Copy Code

