name : class-partialfileservlet.php <?php // https://stackoverflow.com/questions/157318/resumable-downloads-when-using-php-to-send-the-file // User: DaveRandom if (!class_exists('UpdraftPlus_NonExistentFileException')): class UpdraftPlus_NonExistentFileException extends RuntimeException {} endif; if (!class_exists('UpdraftPlus_UnreadableFileException')): class UpdraftPlus_UnreadableFileException extends RuntimeException {} endif; if (!class_exists('UpdraftPlus_UnsatisfiableRangeException')): class UpdraftPlus_UnsatisfiableRangeException extends RuntimeException {} endif; if (!class_exists('UpdraftPlus_InvalidRangeHeaderException')): class UpdraftPlus_InvalidRangeHeaderException extends RuntimeException {} endif; class UpdraftPlus_RangeHeader { /** * The first byte in the file to send (0-indexed), a null value indicates the last * $end bytes * * @var int|null */ private $firstByte; /** * The last byte in the file to send (0-indexed), a null value indicates $start to * EOF * * @var int|null */ private $lastByte; /** * Create a new instance from a Range header string * * @param string $header * @return UpdraftPlus_RangeHeader */ public static function createFromHeaderString($header) { if ($header === null) { return null; } if (!preg_match('/^\s*([A-Za-z]+)\s*=\s*(\d*)\s*-\s*(\d*)\s*(?:,|$)/', $header, $info)) { throw new UpdraftPlus_InvalidRangeHeaderException('Invalid header format'); } else if (strtolower($info[1]) !== 'bytes') { throw new UpdraftPlus_InvalidRangeHeaderException('Unknown range unit: ' . $info[1]); } return new self( $info[2] === '' ? null : $info[2], $info[3] === '' ? null : $info[3] ); } /** * @param int|null $firstByte * @param int|null $lastByte * @throws UpdraftPlus_InvalidRangeHeaderException */ public function __construct($firstByte, $lastByte) { $this->firstByte = $firstByte === null ? $firstByte : (int)$firstByte; $this->lastByte = $lastByte === null ? $lastByte : (int)$lastByte; if ($this->firstByte === null && $this->lastByte === null) { throw new UpdraftPlus_InvalidRangeHeaderException( 'Both start and end position specifiers empty' ); } else if ($this->firstByte < 0 || $this->lastByte < 0) { throw new UpdraftPlus_InvalidRangeHeaderException( 'Position specifiers cannot be negative' ); } else if ($this->lastByte !== null && $this->lastByte < $this->firstByte) { throw new UpdraftPlus_InvalidRangeHeaderException( 'Last byte cannot be less than first byte' ); } } /** * Get the start position when this range is applied to a file of the specified size * * @param int $fileSize * @return int * @throws UpdraftPlus_UnsatisfiableRangeException */ public function getStartPosition($fileSize) { $size = (int)$fileSize; if ($this->firstByte === null) { return ($size - 1) - $this->lastByte; } if ($size <= $this->firstByte) { throw new UpdraftPlus_UnsatisfiableRangeException( 'Start position is after the end of the file' ); } return $this->firstByte; } /** * Get the end position when this range is applied to a file of the specified size * * @param int $fileSize * @return int * @throws UpdraftPlus_UnsatisfiableRangeException */ public function getEndPosition($fileSize) { $size = (int)$fileSize; if ($this->lastByte === null) { return $size - 1; } if ($size <= $this->lastByte) { throw new UpdraftPlus_UnsatisfiableRangeException( 'End position is after the end of the file' ); } return $this->lastByte; } /** * Get the length when this range is applied to a file of the specified size * * @param int $fileSize * @return int * @throws UpdraftPlus_UnsatisfiableRangeException */ public function getLength($fileSize) { $size = (int)$fileSize; return $this->getEndPosition($size) - $this->getStartPosition($size) + 1; } /** * Get a Content-Range header corresponding to this Range and the specified file * size * * @param int $fileSize * @return string */ public function getContentRangeHeader($fileSize) { return 'bytes ' . $this->getStartPosition($fileSize) . '-' . $this->getEndPosition($fileSize) . '/' . $fileSize; } } class UpdraftPlus_PartialFileServlet { /** * The range header on which the data transmission will be based * * @var UpdraftPlus_RangeHeader|null */ private $range; /** * @param UpdraftPlus_RangeHeader $range Range header on which the transmission will be based */ public function __construct($range = null) { $this->range = $range; } /** * Send part of the data in a seekable stream resource to the output buffer * * @param resource $fp Stream resource to read data from * @param int $start Position in the stream to start reading * @param int $length Number of bytes to read * @param int $chunkSize Maximum bytes to read from the file in a single operation */ private function sendDataRange($fp, $start, $length, $chunkSize = 2097152) { if ($start > 0) { fseek($fp, $start, SEEK_SET); } while ($length) { $read = ($length > $chunkSize) ? $chunkSize : $length; $length -= $read; echo fread($fp, $read); } } /** * Send the headers that are included regardless of whether a range was requested * * @param string $fileName * @param int $contentLength * @param string $contentType */ private function sendDownloadHeaders($fileName, $contentLength, $contentType) { header('Content-Type: ' . $contentType); header('Content-Length: ' . $contentLength); header('Content-Disposition: attachment; filename="' . $fileName . '"'); header('Accept-Ranges: bytes'); } /** * Send data from a file based on the current Range header * * @param string $path Local file system path to serve * @param string $contentType MIME type of the data stream */ public function sendFile($path, $contentType = 'application/octet-stream') { // Make sure the file exists and is a file, otherwise we are wasting our time $localPath = realpath($path); if ($localPath === false || !is_file($localPath)) { throw new UpdraftPlus_NonExistentFileException( $path . ' does not exist or is not a file' ); } // Make sure we can open the file for reading if (!$fp = fopen($localPath, 'r')) { throw new UpdraftPlus_UnreadableFileException( 'Failed to open ' . $localPath . ' for reading' ); } $fileSize = filesize($localPath); if ($this->range == null) { // No range requested, just send the whole file header('HTTP/1.1 200 OK'); $this->sendDownloadHeaders(basename($localPath), $fileSize, $contentType); fpassthru($fp); } else { // Send the request range header('HTTP/1.1 206 Partial Content'); header('Content-Range: ' . $this->range->getContentRangeHeader($fileSize)); $this->sendDownloadHeaders( basename($localPath), $this->range->getLength($fileSize), $contentType ); $this->sendDataRange( $fp, $this->range->getStartPosition($fileSize), $this->range->getLength($fileSize) ); } fclose($fp); } }