A simple library to serve static files & documents via PHP (APPLAuD)

HttpFileDispatcher.php

<?php namespace Nfreear\HttpFileDispatcher;

//namespace IET_OU\Frontend\Classes;

/**
 * A simple library to serve static files & documents via PHP.
 *
 * @copyright © Nick Freear, 25 May 2016.
 *
 * @link  http://localhost/applaud/file?f=APPLAuD%20Principles.pdf  Example 1
 * @link  http://localhost/applaud/file?f=Fig1.jpg  Example 2
 */

use Response;

class FileDispatcher
{
    const URI_REGEX = '@\/file\?f=(?P<file>\w[\w\%]+\w\.(?P<ext>\w{2,}))$@';
    const ALLOW_EXT_REGEX = '@^(pdf|docx?|png|jpg)$@i';
    const DISP_INLINE_REGEX = '@^(pdf|png|jpg)$@i';

    const FILE_PATH = '%s/../../../../path/to/files/';

    public static function run()
    {
        $request_uri = filter_input(INPUT_SERVER, 'REQUEST_URI', FILTER_SANITIZE_URL);
        //$file_param  = filter_input(INPUT_GET, 'file', FILTER_SANITIZE_URL);

        if (preg_match(self::URI_REGEX, $request_uri, $matches)) {
            $file = urldecode($matches[ 'file' ]);
            $file_ext = $matches[ 'ext' ];
            $file_path = sprintf(self::FILE_PATH, __DIR__) . $file;

            if (! preg_match(self::ALLOW_EXT_REGEX, $file_ext)) {
                FileDispatcher::debug([ 400, 'Bad file extension', $file, $ext ]);
                return Response::make('Bad Request', 403);
            }

            if (! file_exists($file_path)) {
                //throw new Exception('404 Not Found: ' . $file);
                FileDispatcher::debug([ 404, 'File not found', $file ]);
                // https://octobercms.com/forum/post/returning-404-from-a-component
                return Response::make('File not found', 404);
            }

            self::dispatch($file, $file_path, $file_ext);
        }
    }

    protected static function dispatch($filename, $file_path, $file_ext)
    {
        $info = (object) [
            'filename' => $filename,
            'filesize' => filesize($file_path),
            'mimetype' => self::mimetype($file_path),
            'disposition' => preg_match(self::DISP_INLINE_REGEX, $file_ext) ? 'inline' : 'attachment',
        ];
        $contents = file_get_contents($file_path);

        FileDispatcher::debug([ 'OK', $info ]);

        header('Content-Type: ' . $info->mimetype);
        header('Content-Disposition: ' .sprintf('%s; filename=%s', $info->disposition, $filename));

        echo $contents;
        exit;
    }

    /**
     * @link http://stackoverflow.com/questions/23287341/how-to-get-mime-type-of-a-file-in-php-5-5
     */
    protected static function mimetype($file_path)
    {
        $finfo = finfo_open(FILEINFO_MIME_TYPE);
        $mimetype = finfo_file($finfo, $file_path);
        finfo_close($finfo);
        return $mimetype;
    }

    public static function debug($obj)
    {
        static $count = 0;
        header(sprintf('X-Frontend-%02d: %s', $count, json_encode($obj)));
        $count++;
    }
}