bcit-ci/CodeIgniter

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system/helpers/download_helper.php

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<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2019, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package    CodeIgniter
 * @author    EllisLab Dev Team
 * @copyright    Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright    Copyright (c) 2014 - 2019, British Columbia Institute of Technology (https://bcit.ca/)
 * @license    https://opensource.org/licenses/MIT    MIT License
 * @link    https://codeigniter.com
 * @since    Version 1.0.0
 * @filesource
 */
defined('BASEPATH') OR exit('No direct script access allowed');

/**
 * CodeIgniter Download Helpers
 *
 * @package        CodeIgniter
 * @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    mixed    filename (or an array of local file path => destination 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)
        {
            // Is $filename an array as ['local source path' => 'destination filename']?
            if (is_array($filename))
            {
                if (count($filename) !== 1)
                {
                    return;
                }

                reset($filename);
                $filepath = key($filename);
                $filename = current($filename);

                if (is_int($filepath))
                {
                    return;
                }
            }
            else
            {
                $filepath = $filename;
                $filename = explode('/', str_replace(DIRECTORY_SEPARATOR, '/', $filename));
                $filename = end($filename);
            }

            if ( ! @is_file($filepath) OR ($filesize = @filesize($filepath)) === FALSE)
            {
                return;
            }
        }
        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 =& get_mimes();

            // 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);
        }

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

        // RFC 6266 allows for multibyte filenames, but only in UTF-8,
        // so we have to make it conditional ...
        $charset = strtoupper(config_item('charset'));
        $utf8_filename = ($charset !== 'UTF-8')
            ? get_instance()->utf8->convert_to_utf8($filename, $charset)
            : $filename;
        isset($utf8_filename[0]) && $utf8_filename = " filename*=UTF-8''".rawurlencode($utf8_filename);

        // Generate the server headers
        header('Content-Type: '.$mime);
        header('Content-Disposition: attachment; filename="'.$filename.'";'.$utf8_filename);
        header('Expires: 0');
        header('Content-Transfer-Encoding: binary');
        header('Content-Length: '.$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 the file
        if (@readfile($filepath) === FALSE)
        {
            return;
        }

        exit;
    }
}