mod/pubsubhubbub.php

   1 <?php
   2
   3 use Friendica\App;
   4 use Friendica\Core\Logger;
   5 use Friendica\Database\DBA;
   6 use Friendica\DI;
   7 use Friendica\Model\PushSubscriber;
   8 use Friendica\Util\Network;
   9 use Friendica\Util\Strings;
  10
  11 function post_var($name) {
  12         return !empty($_POST[$name]) ? Strings::escapeTags(trim($_POST[$name])) : '';
  13 }
  14
  15 function pubsubhubbub_init(App $a) {
  16         // PuSH subscription must be considered "public" so just block it
  17         // if public access isn't enabled.
  18         if (DI::config()->get('system', 'block_public')) {
  19                 throw new \Friendica\Network\HTTPException\ForbiddenException();
  20         }
  21
  22         // Subscription request from subscriber
  23         // https://pubsubhubbub.googlecode.com/git/pubsubhubbub-core-0.4.html#anchor4
  24         // Example from GNU Social:
  25         // [hub_mode] => subscribe
  26         // [hub_callback] => http://status.local/main/push/callback/1
  27         // [hub_verify] => sync
  28         // [hub_verify_token] => af11...
  29         // [hub_secret] => af11...
  30         // [hub_topic] => http://friendica.local/dfrn_poll/sazius
  31
  32         if ($_SERVER['REQUEST_METHOD'] === 'POST') {
  33                 $hub_mode = post_var('hub_mode');
  34                 $hub_callback = post_var('hub_callback');
  35                 $hub_verify_token = post_var('hub_verify_token');
  36                 $hub_secret = post_var('hub_secret');
  37                 $hub_topic = post_var('hub_topic');
  38
  39                 // check for valid hub_mode
  40                 if ($hub_mode === 'subscribe') {
  41                         $subscribe = 1;
  42                 } elseif ($hub_mode === 'unsubscribe') {
  43                         $subscribe = 0;
  44                 } else {
  45                         Logger::log("Invalid hub_mode=$hub_mode, ignoring.");
  46                         throw new \Friendica\Network\HTTPException\NotFoundException();
  47                 }
  48
  49                 Logger::log("$hub_mode request from " . $_SERVER['REMOTE_ADDR']);
  50
  51                 if ($a->argc > 1) {
  52                         // Normally the url should now contain the nick name as last part of the url
  53                         $nick = $a->argv[1];
  54                 } else {
  55                         // Get the nick name from the topic as a fallback
  56                         $nick = $hub_topic;
  57                 }
  58                 // Extract nick name and strip any .atom extension
  59                 $nick = basename($nick, '.atom');
  60
  61                 if (!$nick) {
  62                         Logger::log('Bad hub_topic=$hub_topic, ignoring.');
  63                         throw new \Friendica\Network\HTTPException\NotFoundException();
  64                 }
  65
  66                 // fetch user from database given the nickname
  67                 $condition = ['nickname' => $nick, 'account_expired' => false, 'account_removed' => false];
  68                 $owner = DBA::selectFirst('user', ['uid', 'hidewall', 'nickname'], $condition);
  69                 if (!DBA::isResult($owner)) {
  70                         Logger::log('Local account not found: ' . $nick . ' - topic: ' . $hub_topic . ' - callback: ' . $hub_callback);
  71                         throw new \Friendica\Network\HTTPException\NotFoundException();
  72                 }
  73
  74                 // abort if user's wall is supposed to be private
  75                 if ($owner['hidewall']) {
  76                         Logger::log('Local user ' . $nick . 'has chosen to hide wall, ignoring.');
  77                         throw new \Friendica\Network\HTTPException\ForbiddenException();
  78                 }
  79
  80                 // get corresponding row from contact table
  81                 $condition = ['uid' => $owner['uid'], 'blocked' => false,
  82                         'pending' => false, 'self' => true];
  83                 $contact = DBA::selectFirst('contact', ['poll'], $condition);
  84                 if (!DBA::isResult($contact)) {
  85                         Logger::log('Self contact for user ' . $owner['uid'] . ' not found.');
  86                         throw new \Friendica\Network\HTTPException\NotFoundException();
  87                 }
  88
  89                 // sanity check that topic URLs are the same
  90                 $hub_topic2 = str_replace('/feed/', '/dfrn_poll/', $hub_topic);
  91                 $self = DI::baseUrl() . '/api/statuses/user_timeline/' . $owner['nickname'] . '.atom';
  92
  93                 if (!Strings::compareLink($hub_topic, $contact['poll']) && !Strings::compareLink($hub_topic2, $contact['poll']) && !Strings::compareLink($hub_topic, $self)) {
  94                         Logger::log('Hub topic ' . $hub_topic . ' != ' . $contact['poll']);
  95                         throw new \Friendica\Network\HTTPException\NotFoundException();
  96                 }
  97
  98                 // do subscriber verification according to the PuSH protocol
  99                 $hub_challenge = Strings::getRandomHex(40);
 100
 101                 $params = http_build_query([
 102                         'hub.mode' => $subscribe == 1 ? 'subscribe' : 'unsubscribe',
 103                         'hub.topic' => $hub_topic,
 104                         'hub.challenge' => $hub_challenge,
 105                         'hub.verify_token' => $hub_verify_token,
 106
 107                         // lease time is hard coded to one week (in seconds)
 108                         // we don't actually enforce the lease time because GNU
 109                         // Social/StatusNet doesn't honour it (yet)
 110                         'hub.lease_seconds' => 604800,
 111                 ]);
 112
 113                 $hub_callback = rtrim($hub_callback, ' ?&#');
 114                 $separator = parse_url($hub_callback, PHP_URL_QUERY) === null ? '?' : '&';
 115
 116                 $fetchResult = Network::fetchUrlFull($hub_callback . $separator . $params);
 117                 $body = $fetchResult->getBody();
 118                 $ret = $fetchResult->getReturnCode();
 119
 120                 // give up if the HTTP return code wasn't a success (2xx)
 121                 if ($ret < 200 || $ret > 299) {
 122                         Logger::log("Subscriber verification for $hub_topic at $hub_callback returned $ret, ignoring.");
 123                         throw new \Friendica\Network\HTTPException\NotFoundException();
 124                 }
 125
 126                 // check that the correct hub_challenge code was echoed back
 127                 if (trim($body) !== $hub_challenge) {
 128                         Logger::log("Subscriber did not echo back hub.challenge, ignoring.");
 129                         Logger::log("\"$hub_challenge\" != \"".trim($body)."\"");
 130                         throw new \Friendica\Network\HTTPException\NotFoundException();
 131                 }
 132
 133                 PushSubscriber::renew($owner['uid'], $nick, $subscribe, $hub_callback, $hub_topic, $hub_secret);
 134
 135                 throw new \Friendica\Network\HTTPException\AcceptedException();
 136         }
 137         exit();
 138 }