save.php

<?php
/*
Copyright 2017 Ziadin Givan

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

https://github.com/givanz/VvvebJs
*/

define('MAX_FILE_LIMIT', 1024 * 1024 * 2);//2 Megabytes max html file size

function sanitizeFileName($file)
{
	//sanitize, remove double dot .. and remove get parameters if any
	$file = __DIR__ . '/' . preg_replace('@\?.*$@' , '', preg_replace('@\.{2,}@' , '', preg_replace('@[^\/\\a-zA-Z0-9\-\._]@', '', $file)));
	return $file;
}

$html = "";
if (isset($_POST['startTemplateUrl']) && !empty($_POST['startTemplateUrl'])) 
{
	$startTemplateUrl = sanitizeFileName($_POST['startTemplateUrl']);
	$html = file_get_contents($startTemplateUrl);
} else if (isset($_POST['html']))
{
	$html = substr($_POST['html'], 0, MAX_FILE_LIMIT);
}

$file = sanitizeFileName($_POST['file']);

if (file_put_contents($file, $html)) {
	echo "File saved $file";
} else {
	header($_SERVER['SERVER_PROTOCOL'] . ' 500 Internal Server Error', true, 500);
	echo "Error saving file  $file\nPossible causes are missing write permission or incorrect file path!";
}