Core/src/Helpers/download_helper.php

<?php
/**
 * FuzeWorks.
 *
 * The FuzeWorks MVC PHP FrameWork
 *
 * Copyright (C) 2015   TechFuze
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @author    TechFuze
 * @copyright Copyright (c) 2013 - 2016, Techfuze. (http://techfuze.net)
 * @copyright Copyright (c) 1996 - 2015, Free Software Foundation, Inc. (http://www.fsf.org/)
 * @license   http://opensource.org/licenses/GPL-3.0 GPLv3 License
 *
 * @link  http://fuzeworks.techfuze.net
 * @since Version 0.0.1
 *
 * @version Version 0.0.1
 */

/**
 * FuzeWorks Download Helpers
 * 
 * Converted from CodeIgniter.
 *
 * @package		FuzeWorks
 * @subpackage	Helpers
 * @category	Helpers
 * @author		EllisLab Dev Team
 * @link		https://codeigniter.com/user_guide/helpers/download_helper.html
 */

// ------------------------------------------------------------------------

if ( ! function_exists('force_download'))
{
	/**
	 * Force Download
	 *
	 * Generates headers that force a download to happen
	 *
	 * @param	string	filename
	 * @param	mixed	the data to be downloaded
	 * @param	bool	whether to try and send the actual file MIME type
	 * @return	void
	 */
	function force_download($filename = '', $data = '', $set_mime = FALSE)
	{
		if ($filename === '' OR $data === '')
		{
			return;
		}
		elseif ($data === NULL)
		{
			if ( ! @is_file($filename) OR ($filesize = @filesize($filename)) === FALSE)
			{
				return;
			}

			$filepath = $filename;
			$filename = explode('/', str_replace(DIRECTORY_SEPARATOR, '/', $filename));
			$filename = end($filename);
		}
		else
		{
			$filesize = strlen($data);
		}

		// Set the default MIME type to send
		$mime = 'application/octet-stream';

		$x = explode('.', $filename);
		$extension = end($x);

		if ($set_mime === TRUE)
		{
			if (count($x) === 1 OR $extension === '')
			{
				/* If we're going to detect the MIME type,
				 * we'll need a file extension.
				 */
				return;
			}

			// Load the mime types
			$mimes = Config::get('mimes')->toArray();

			// Only change the default MIME if we can find one
			if (isset($mimes[$extension]))
			{
				$mime = is_array($mimes[$extension]) ? $mimes[$extension][0] : $mimes[$extension];
			}
		}

		/* It was reported that browsers on Android 2.1 (and possibly older as well)
		 * need to have the filename extension upper-cased in order to be able to
		 * download it.
		 *
		 * Reference: http://digiblog.de/2011/04/19/android-and-the-download-file-headers/
		 */
		if (count($x) !== 1 && isset($_SERVER['HTTP_USER_AGENT']) && preg_match('/Android\s(1|2\.[01])/', $_SERVER['HTTP_USER_AGENT']))
		{
			$x[count($x) - 1] = strtoupper($extension);
			$filename = implode('.', $x);
		}

		if ($data === NULL && ($fp = @fopen($filepath, 'rb')) === FALSE)
		{
			return;
		}

		// Clean output buffer
		if (ob_get_level() !== 0 && @ob_end_clean() === FALSE)
		{
			@ob_clean();
		}

		// Generate the server headers
		header('Content-Type: '.$mime);
		header('Content-Disposition: attachment; filename="'.$filename.'"');
		header('Expires: 0');
		header('Content-Transfer-Encoding: binary');
		header('Content-Length: '.$filesize);
		header('Cache-Control: private, no-transform, no-store, must-revalidate');

		// If we have raw data - just dump it
		if ($data !== NULL)
		{
			exit($data);
		}

		// Flush 1MB chunks of data
		while ( ! feof($fp) && ($data = fread($fp, 1048576)) !== FALSE)
		{
			echo $data;
		}

		fclose($fp);
		exit;
	}
}