system/helpers/download_helper.php

<?php  if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2006, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

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

/**
 * CodeIgniter Download Helpers
 *
 * @package		CodeIgniter
 * @subpackage	Helpers
 * @category	Helpers
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/helpers/download_helper.html
 */

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

/**
 * Force Download
 *
 * Generates headers that force a download to happen
 *
 * @access	public
 * @param	string	filename
 * @param	mixed	the data to be downloaded
 * @return	void
 */	
function force_download($filename = '', $data = '')
{
	if ($filename == '' OR $data == '')
	{
		return FALSE;
	}

	// Try to determine if the filename includes a file extension.
	// We need it in order to set the MIME type
	if (FALSE === strpos($filename, '.'))
	{
		return FALSE;
	}
	
	// Grab the file extension
	$x = explode('.', $filename);
	$extension = end($x);

	// Load the mime types
	@include(APPPATH.'config/mimes'.EXT);
	
	// Set a default mime if we can't find it
	if ( ! isset($mimes[$extension]))
	{
		$mime = 'application/octet-stream';
	}
	else
	{
		$mime = (is_array($mimes[$extension])) ? $mimes[$extension][0] : $mimes[$extension];
	}
	
	// Generate the server headers
	if (strstr($_SERVER['HTTP_USER_AGENT'], "MSIE"))
	{
		header('Content-Type: "'.$mime.'"');
		header('Content-Disposition: attachment; filename="'.$filename.'"');
		header('Expires: 0');
		header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
		header("Content-Transfer-Encoding: binary");
		header('Pragma: public');
		header("Content-Length: ".strlen($data));
	}
	else
	{
		header('Content-Type: "'.$mime.'"');
		header('Content-Disposition: attachment; filename="'.$filename.'"');
		header("Content-Transfer-Encoding: binary");
		header('Expires: 0');
		header('Pragma: no-cache');
		header("Content-Length: ".strlen($data));
	}
	
	echo $data;
}


?>