mod/pubsubhubbub.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 use Friendica\App;
  23 use Friendica\Core\Logger;
  24 use Friendica\Core\System;
  25 use Friendica\Database\DBA;
  26 use Friendica\DI;
  27 use Friendica\Model\PushSubscriber;
  28 use Friendica\Util\Strings;
  29
  30 function pubsubhubbub_init(App $a) {
  31         // PuSH subscription must be considered "public" so just block it
  32         // if public access isn't enabled.
  33         if (DI::config()->get('system', 'block_public')) {
  34                 throw new \Friendica\Network\HTTPException\ForbiddenException();
  35         }
  36
  37         // Subscription request from subscriber
  38         // https://pubsubhubbub.googlecode.com/git/pubsubhubbub-core-0.4.html#anchor4
  39         // Example from GNU Social:
  40         // [hub_mode] => subscribe
  41         // [hub_callback] => http://status.local/main/push/callback/1
  42         // [hub_verify] => sync
  43         // [hub_verify_token] => af11...
  44         // [hub_secret] => af11...
  45         // [hub_topic] => http://friendica.local/dfrn_poll/sazius
  46
  47         if (DI::args()->getMethod() === App\Router::POST) {
  48                 $hub_mode         = $_POST['hub_mode']         ?? '';
  49                 $hub_callback     = $_POST['hub_callback']     ?? '';
  50                 $hub_verify_token = $_POST['hub_verify_token'] ?? '';
  51                 $hub_secret       = $_POST['hub_secret']       ?? '';
  52                 $hub_topic        = $_POST['hub_topic']        ?? '';
  53
  54                 // check for valid hub_mode
  55                 if ($hub_mode === 'subscribe') {
  56                         $subscribe = 1;
  57                 } elseif ($hub_mode === 'unsubscribe') {
  58                         $subscribe = 0;
  59                 } else {
  60                         Logger::notice("Invalid hub_mode=$hub_mode, ignoring.");
  61                         throw new \Friendica\Network\HTTPException\NotFoundException();
  62                 }
  63
  64                 Logger::info("$hub_mode request from " . $_SERVER['REMOTE_ADDR']);
  65
  66                 if (DI::args()->getArgc() > 1) {
  67                         // Normally the url should now contain the nick name as last part of the url
  68                         $nick = DI::args()->getArgv()[1];
  69                 } else {
  70                         // Get the nick name from the topic as a fallback
  71                         $nick = $hub_topic;
  72                 }
  73                 // Extract nick name and strip any .atom extension
  74                 $nick = basename($nick, '.atom');
  75
  76                 if (!$nick) {
  77                         Logger::notice('Bad hub_topic=$hub_topic, ignoring.');
  78                         throw new \Friendica\Network\HTTPException\NotFoundException();
  79                 }
  80
  81                 // fetch user from database given the nickname
  82                 $condition = ['nickname' => $nick, 'account_expired' => false, 'account_removed' => false];
  83                 $owner = DBA::selectFirst('user', ['uid', 'nickname'], $condition);
  84                 if (!DBA::isResult($owner)) {
  85                         Logger::notice('Local account not found: ' . $nick . ' - topic: ' . $hub_topic . ' - callback: ' . $hub_callback);
  86                         throw new \Friendica\Network\HTTPException\NotFoundException();
  87                 }
  88
  89                 // get corresponding row from contact table
  90                 $condition = ['uid' => $owner['uid'], 'blocked' => false,
  91                         'pending' => false, 'self' => true];
  92                 $contact = DBA::selectFirst('contact', ['poll'], $condition);
  93                 if (!DBA::isResult($contact)) {
  94                         Logger::notice('Self contact for user ' . $owner['uid'] . ' not found.');
  95                         throw new \Friendica\Network\HTTPException\NotFoundException();
  96                 }
  97
  98                 // sanity check that topic URLs are the same
  99                 $hub_topic2 = str_replace('/feed/', '/dfrn_poll/', $hub_topic);
 100                 $self = DI::baseUrl() . '/api/statuses/user_timeline/' . $owner['nickname'] . '.atom';
 101
 102                 if (!Strings::compareLink($hub_topic, $contact['poll']) && !Strings::compareLink($hub_topic2, $contact['poll']) && !Strings::compareLink($hub_topic, $self)) {
 103                         Logger::notice('Hub topic ' . $hub_topic . ' != ' . $contact['poll']);
 104                         throw new \Friendica\Network\HTTPException\NotFoundException();
 105                 }
 106
 107                 // do subscriber verification according to the PuSH protocol
 108                 $hub_challenge = Strings::getRandomHex(40);
 109
 110                 $params = http_build_query([
 111                         'hub.mode' => $subscribe == 1 ? 'subscribe' : 'unsubscribe',
 112                         'hub.topic' => $hub_topic,
 113                         'hub.challenge' => $hub_challenge,
 114                         'hub.verify_token' => $hub_verify_token,
 115
 116                         // lease time is hard coded to one week (in seconds)
 117                         // we don't actually enforce the lease time because GNU
 118                         // Social/StatusNet doesn't honour it (yet)
 119                         'hub.lease_seconds' => 604800,
 120                 ]);
 121
 122                 $hub_callback = rtrim($hub_callback, ' ?&#');
 123                 $separator = parse_url($hub_callback, PHP_URL_QUERY) === null ? '?' : '&';
 124
 125                 $fetchResult = DI::httpClient()->fetchFull($hub_callback . $separator . $params);
 126                 $body = $fetchResult->getBody();
 127                 $ret = $fetchResult->getReturnCode();
 128
 129                 // give up if the HTTP return code wasn't a success (2xx)
 130                 if ($ret < 200 || $ret > 299) {
 131                         Logger::notice("Subscriber verification for $hub_topic at $hub_callback returned $ret, ignoring.");
 132                         throw new \Friendica\Network\HTTPException\NotFoundException();
 133                 }
 134
 135                 // check that the correct hub_challenge code was echoed back
 136                 if (trim($body) !== $hub_challenge) {
 137                         Logger::notice("Subscriber did not echo back hub.challenge, ignoring.");
 138                         Logger::notice("\"$hub_challenge\" != \"".trim($body)."\"");
 139                         throw new \Friendica\Network\HTTPException\NotFoundException();
 140                 }
 141
 142                 PushSubscriber::renew($owner['uid'], $nick, $subscribe, $hub_callback, $hub_topic, $hub_secret);
 143
 144                 throw new \Friendica\Network\HTTPException\AcceptedException();
 145         }
 146         System::exit();
 147 }