TiddlyWiki 5 PHP Saver

saver.php

<?php
$uri = $_SERVER['REQUEST_URI'];
$ext = pathinfo($uri, PATHINFO_EXTENSION);
$full_path = $_SERVER['DOCUMENT_ROOT'] . $uri . (empty($ext) ? '.html' : '');

/**
 * if (@strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) == $last_modified_time || 
 *     trim($_SERVER['HTTP_IF_NONE_MATCH']) == $etag) { 
 *     header("HTTP/1.1 304 Not Modified"); 
 * exit; 
 */

switch (strtoupper($_SERVER['REQUEST_METHOD'])) {
    case 'OPTIONS':
        header('DAV: 1, 2');
        break;
    case 'HEAD':
        if (file_exists($full_path)) {
            $last_modified_time = filemtime($full_path); 
            $etag = md5_file($full_path); 

            header("Last-Modified: ".gmdate("D, d M Y H:i:s", $last_modified_time)." GMT");
            header("ETag: $etag");
        } else {
            header('404 Not Found');
        }
        break;
    case 'PUT':
        $inputStream = fopen('php://input', 'r');
        $outputStream = fopen($full_path, 'w');
        stream_copy_to_stream($inputStream, $outputStream);
        fclose($inputStream);
        fclose($outputStream);
        break;
    case 'GET':
    default:
        if (preg_match('/\.(?:png|jpg|jpeg|gif|html)$/', $uri)) {
            return false;    // serve the requested resource as-is.
        } else {
            if (file_exists($full_path)) {
                readfile($full_path);
            } else {
                header('404 Not Found');
                echo $full_path . ' is not found.';
            }
        }
        break;
}