<?php
/**
* @package AkeebaBackup
* @copyright Copyright (c)2006-2016 Nicholas K. Dionysopoulos
* @license GNU General Public License version 3, or later
*/
namespace Akeeba\Backup\Site\Model\Json\Task;
// Protect from unauthorized access
defined('_JEXEC') or die();
use Akeeba\Engine\Factory;
use Akeeba\Engine\Platform;
/**
* Download a chunk of a backup archive over HTTP
*/
class Download extends AbstractTask
{
/**
* Execute the JSON API task
*
* @param array $parameters The parameters to this task
*
* @return mixed
*
* @throws \RuntimeException In case of an error
*/
public function execute(array $parameters = array())
{
// Get the passed configuration values
$defConfig = array(
'backup_id' => 0,
'part_id' => 1,
'segment' => 1,
'chunk_size' => 1
);
$defConfig = array_merge($defConfig, $parameters);
$backup_id = (int)$defConfig['backup_id'];
$part_id = (int)$defConfig['part_id'];
$segment = (int)$defConfig['segment'];
$chunk_size = (int)$defConfig['chunk_size'];
$backup_stats = Platform::getInstance()->get_statistics($backup_id);
if (empty($backup_stats))
{
// Backup record doesn't exist
throw new \RuntimeException('Invalid backup record identifier', 404);
}
$files = Factory::getStatistics()->get_all_filenames($backup_stats);
if ((count($files) < $part_id) || ($part_id <= 0))
{
// Invalid part
throw new \RuntimeException('Invalid backup part', 404);
}
$file = $files[ $part_id - 1 ];
$filesize = @filesize($file);
$seekPos = $chunk_size * 1048576 * ($segment - 1);
if ($seekPos > $filesize)
{
// Trying to seek past end of file
throw new \RuntimeException('Invalid segment', 404);
}
$fp = fopen($file, 'rb');
if ($fp === false)
{
// Could not read file
throw new \RuntimeException('Error reading backup archive', 500);
}
rewind($fp);
if (fseek($fp, $seekPos, SEEK_SET) === -1)
{
// Could not seek to position
throw new \RuntimeException('Error reading specified segment', 500);
}
$buffer = fread($fp, 1048576);
if ($buffer === false)
{
throw new \RuntimeException('Error reading specified segment', 500);
}
fclose($fp);
return base64_encode($buffer);
}
}