Jones
/
unocck


			
				
					
						
						
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							<?php

/*
  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program. If not, see <http://www.gnu.org/licenses/>.
*/

// example of a post censored by mastodon.uno: https://livellosegreto.it/@xabacadabra/110662830871887169

require 'lib/ght.php';
require 'lib/ckratelimit.php';

const SNAME='unocck';
const SVERS='0.1.1';
const SREPO='https://git.lattuga.net/jones/unocck';
const MULEN=1024;
const INIFP='sec/conf.ini';
const RLFP='sec/rl.state';

header('Content-Language: en');

$usname=ucfirst(SNAME);
$timeout=5;
$cjr=rand(0,999999);

$conf=@parse_ini_file(INIFP,false,INI_SCANNER_RAW);
if ($conf===false)
	die('Could not open configuration file.');
elseif (!isset($conf['host']) || !isset($conf['hostdesc']) || !isset($conf['token']) || !isset($conf['maintref']))
	die('Configuration file is malformed.');

if (file_exists(RLFP)) {
	$buf=@file(RLFP,FILE_IGNORE_NEW_LINES);
	if ($buf===false)
		die('Could not open rate limiting state file.');
	if (count($buf)!=2 || preg_match('#^\d+$#',$buf[0])!==1 || preg_match('#^\d+$#',$buf[1])!==1)
		die('Malformed rate limiting state file.');
	$rl=['remaining'=>$buf[0]+0,'restime'=>$buf[1]+0];
} else {
	$rl=['remaining'=>400,'restime'=>0];
}

$now=time();
if ($rl['remaining']==10 && $now<=$rl['restime'])// ten to leave a margin for "many people using it"
	die("Sorry, this {$usname} instance has reached rate limit on «{$conf['host']}», please wait at least ".ght($rl['restime']-$now,null,0).'.');

$errors=[];

if (isset($argv[1]))
	$_GET=['purl'=>$argv[1]];

if (isset($_GET['purl'])) {
	if (strlen($_GET['purl'])>MULEN) {
		$_GET['purl']='';
		$errors[]='“Post URL” is too long';
	}
	$_GET['purl']=trim($_GET['purl']);
	if ($_GET['purl']!='' && preg_match('#^https?://#',$_GET['purl'])!==1)// todo: make it better
		$errors[]='“Post URL” is not a valid http(s) address';
} else {
	$_GET['purl']='';
}

if ($_GET['purl']!=='')
	$purlhn=preg_replace('#^https?://([^/]+).*$#','$1',$_GET['purl']);

if (count($errors)>0)
	$errors='<div class="warning">There are some errors in the values you submitted<ul><li>'.implode('</li><li>',$errors).'</li></ul></div><div class="horsep"></div>';
else
	$errors='';

echo "<!DOCTYPE HTML>
<html lang=\"en\">
<head>
<title>{$usname}</title>
<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">
<meta name=\"description\" content=\"A tool to check if {$conf['host']} is censoring a given post\">
<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no\">
<meta property=\"og:image\" content=\"imgs/ogimage.png\">
<link rel=\"icon\" type=\"image/png\" href=\"imgs/icon-16.png\" sizes=\"16x16\">
<link rel=\"icon\" type=\"image/png\" href=\"imgs/icon-32.png\" sizes=\"32x32\">
<link rel=\"icon\" type=\"image/png\" href=\"imgs/icon-192.png\" sizes=\"192x192\">
<link rel=\"icon\" type=\"image/png\" href=\"imgs/icon-512.png\" sizes=\"512x512\">
<link rel=\"apple-touch-icon-precomposed\" href=\"imgs/icon-180.png\">
<link rel=\"stylesheet\" type=\"text/css\" href=\"css/main.css?v={$cjr}\">
</head>
<body>
<div id=\"main\">
<h1>{$usname}</h1>
<div class=\"normtext\">
<p class=\"firstp\">Hello, this is a {$usname} instance. {$usname} is a tool to easily check if a Mastodon instance is censoring a given fediverse post. This {$usname} instance is set to check «{$conf['host']}», {$conf['hostdesc']}. It works by querying {$conf['host']}’s <a href=\"https://docs.joinmastodon.org/methods/search/#v2\">/api/v2/search</a> API endpoint with the credentials of an application defined inside a {$conf['host']} account, but to avoid false positives it does so only after it has verified that the URL you passed to it actually points to a publicly accessible ActivityPub object.</p>
<p>{$usname} does not use cookies or Javascript and does not store any data about you anywhere.</p>
<p>You can find {$usname}’s code <a href=\"".SREPO."\">here</a>.</p>
<p>This {$usname} instance is maintained by {$conf['maintref']}.</p>
</div>
<div class=\"horsep\"></div>
".$errors."
<h2>Check</h2>
<form method=\"get\" id=\"mainform\" name=\"mainform\">
<div class=\"inputdiv\"><label for=\"purl\">Post URL</label><input type=\"text\" id=\"purl\" name=\"purl\" class=\"input\" placeholder=\"Example: https://mastodon.whatever.net/@user/110123412349306591\" value=\"{$_GET['purl']}\" maxlength=\"".MULEN."\" required></div>
<div class=\"lastinputdiv\"><button type=\"submit\" id=\"button\" class=\"button\">Check</button></div>\n</form>\n";

if ($errors=='' && $_GET['purl']!='') {
	echo "<div class=\"horsep\"></div>\n";
	$context=[
		'http'=>[
			'header'=>"Content-type: application/x-www-form-urlencoded\r\nAccept: application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\"\r\n",
			'method'=>'GET',
			'ignore_errors'=>true,
			'user_agent'=>'Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0',
			'timeout'=>5
		]
	];
	if (isset($conf['proxy']))
		$context['http']['proxy']=$conf['proxy'];
	$http_response_header=null;
	$res=@file_get_contents($_GET['purl'],false,stream_context_create($context));
	/*$xres=json_decode($res,true);
	echo preprint($xres);*/
	if (isset($http_response_header))
		$hcode=gethttpcode($http_response_header);
	if ($res===false || !isset($http_response_header)) {
		echo "<div class=\"error\">Error: {$usname} could not connect to «{$purlhn}» and won’t proceed with the check.</div>\n";
	} elseif ($hcode[0]!='2') {
		if ($hcode[0]=='5')
			echo "<div class=\"error\">«{$purlhn}» returned a server error. {$usname} won’t proceed with the check.</div>\n";
		elseif ($hcode[0]=='4')
			echo "<div class=\"error\">Error: {$usname} could not access the “Post URL” you passed to it: probably the post visibility is not public/unlisted, or you passed a wrong URL. {$usname} won’t proceed with the check.</div>\n";
		elseif ($hcode[0]=='3')
			echo "<div class=\"error\">Error: the “Post URL” you passed to {$usname} redirects, and since its programmer is lazy, {$usname} currently only accepts URLs which point to original posts (on Mastodon web you can copy a post’s original URL by opening the “three vertical dots” menu you find on every post and selecting “Copy link to post”). {$usname} won’t proceed with the check.</div>\n";
		elseif ($hcode[0]=='1')
			echo "<div class=\"error\">«{$purlhn}» returned an unexpected and useless informational message. {$usname} won’t proceed with the check.</div>\n";
		else
			echo "<div class=\"error\">«{$purlhn}» returned an unexpected HTTP code. {$usname} won’t proceed with the check.</div>\n";
	} elseif (null===$res=@json_decode($res,true)) {
		echo "<div class=\"error\">Error: «{$purlhn}» returned data which could not be parsed as JSON (".json_last_error().': '.json_last_error_msg().").</div>\n";
	} elseif (isset($res['error'])) {
		echo "<div class=\"error\">Error: «{$purlhn}» returned «".htmlentities($res['error'])."». {$usname} won’t proceed with the check.</div>\n";
	} elseif (!isset($res['@context'][0]) || $res['@context'][0]!='https://www.w3.org/ns/activitystreams') {
		echo "<div class=\"error\">Error: the “Post URL” you passed to {$usname} doesn’t point to an ActivityPub post. {$usname} won’t proceed with the check.</div>\n";
	} else {
		$context['http']['header']="Content-type: application/x-www-form-urlencoded\r\nAccept: application/json\r\nAuthorization: Bearer {$conf['token']}\r\n";
		$http_response_header=null;
		$hhost=htmlentities($conf['host']);
		$url=$conf['host'].'/api/v2/search?q='.urlencode($_GET['purl']).'&type=statuses&resolve=1&limit=1';
		$hurl=htmlentities($url);
		//while (true) {
			$res=@file_get_contents('https://'.$url,false,stream_context_create($context));
			if (isset($http_response_header))
				$rl=ckratelimit($http_response_header);
			//echo preprint($rl);
			if (isset($rl['ok']) && $rl['ok'] && @file_put_contents(RLFP,$rl['remaining']."\n".($rl['sleep']+time())."\n")===false)
				echo "<div class=\"warning\">Warning: could not write to rate limit state file.</div>\n";
			/*if ($rl['remaining']==0)
				break;
			usleep(250000);
		}*/
		if ($res===false) {
			echo "<div class=\"error\">Error: could not connect to «{$hhost}».</div>\n";
		} elseif (null===$res=@json_decode($res,true)) {
			echo "<div class=\"error\">Error: «{$hurl}» returned data which could not be parsed as JSON (".json_last_error().': '.json_last_error_msg().").</div>\n";
		} elseif (isset($res['error'])) {
			echo "<div class=\"error\">Error: «{$hurl}» replied with this error message: «".htmlentities($res['error'])."».</div>\n";
		} elseif (!isset($res['statuses'])) {
			echo "<div class=\"error\">Error: «{$hurl}» returned data in an unexpected format.</div>\n";
		} else {
			if (isset($res['statuses'][0]['id']))
				echo "<div class=\"neutral\">\nPost is not censored.\n</div>\n";
			else
				echo "<div class=\"neutral\">\nPost is censored.\n</div>\n";
		}
	}
}

if (isset($conf['footer']))
	echo "<div id=\"almfooter\">{$conf['footer']}</div>\n";

echo "<div id=\"footer\"><a href=\"".SREPO."\">".SNAME." ".SVERS."</a></div>
</div>
</body>
</html>\n";

function preprint($var) {
	return '<pre>'.print_r($var,true)."</pre>\n";
}

function gethttpcode($headers) {
	return preg_replace('#^[^ ]+ (\d+).*$#','$1',$headers[0]);
}

?>