mod/pubsubhubbub.php

   1 <?php
   2
   3 use Friendica\App;
   4 use Friendica\Core\Config;
   5 use Friendica\Core\System;
   6 use Friendica\Database\DBA;
   7 use Friendica\Database\DBM;
   8 use Friendica\Model\PushSubscriber;
   9 use Friendica\Util\Network;
  10
  11 function post_var($name) {
  12         return (x($_POST, $name)) ? notags(trim($_POST[$name])) : '';
  13 }
  14
  15 function pubsubhubbub_init(App $a) {
  16         // PuSH subscription must be considered "public" so just block it
  17         // if public access isn't enabled.
  18         if (Config::get('system', 'block_public')) {
  19                 System::httpExit(403);
  20         }
  21
  22         // Subscription request from subscriber
  23         // https://pubsubhubbub.googlecode.com/git/pubsubhubbub-core-0.4.html#anchor4
  24         // Example from GNU Social:
  25         // [hub_mode] => subscribe
  26         // [hub_callback] => http://status.local/main/push/callback/1
  27         // [hub_verify] => sync
  28         // [hub_verify_token] => af11...
  29         // [hub_secret] => af11...
  30         // [hub_topic] => http://friendica.local/dfrn_poll/sazius
  31
  32         if ($_SERVER['REQUEST_METHOD'] === 'POST') {
  33                 $hub_mode = post_var('hub_mode');
  34                 $hub_callback = post_var('hub_callback');
  35                 $hub_verify = post_var('hub_verify');
  36                 $hub_verify_token = post_var('hub_verify_token');
  37                 $hub_secret = post_var('hub_secret');
  38                 $hub_topic = post_var('hub_topic');
  39
  40                 // check for valid hub_mode
  41                 if ($hub_mode === 'subscribe') {
  42                         $subscribe = 1;
  43                 } elseif ($hub_mode === 'unsubscribe') {
  44                         $subscribe = 0;
  45                 } else {
  46                         logger("Invalid hub_mode=$hub_mode, ignoring.");
  47                         System::httpExit(404);
  48                 }
  49
  50                 logger("$hub_mode request from " . $_SERVER['REMOTE_ADDR']);
  51
  52                 // get the nick name from the topic, a bit hacky but needed as a fallback
  53                 $nick = substr(strrchr($hub_topic, "/"), 1);
  54
  55                 // Normally the url should now contain the nick name as last part of the url
  56                 if ($a->argc > 1) {
  57                         $nick = $a->argv[1];
  58                 }
  59
  60                 if (!$nick) {
  61                         logger('Bad hub_topic=$hub_topic, ignoring.');
  62                         System::httpExit(404);
  63                 }
  64
  65                 // fetch user from database given the nickname
  66                 $condition = ['nickname' => $nick, 'account_expired' => false, 'account_removed' => false];
  67                 $owner = DBA::selectFirst('user', ['uid', 'hidewall'], $condition);
  68                 if (!DBM::is_result($owner)) {
  69                         logger('Local account not found: ' . $nick . ' - topic: ' . $hub_topic . ' - callback: ' . $hub_callback);
  70                         System::httpExit(404);
  71                 }
  72
  73                 // abort if user's wall is supposed to be private
  74                 if ($owner['hidewall']) {
  75                         logger('Local user ' . $nick . 'has chosen to hide wall, ignoring.');
  76                         System::httpExit(403);
  77                 }
  78
  79                 // get corresponding row from contact table
  80                 $condition = ['uid' => $owner['uid'], 'blocked' => false,
  81                         'pending' => false, 'self' => true];
  82                 $contact = DBA::selectFirst('contact', ['poll'], $condition);
  83                 if (!DBM::is_result($contact)) {
  84                         logger('Self contact for user ' . $owner['uid'] . ' not found.');
  85                         System::httpExit(404);
  86                 }
  87
  88                 // sanity check that topic URLs are the same
  89                 $hub_topic2 = str_replace('/feed/', '/dfrn_poll/', $hub_topic);
  90                 if (!link_compare($hub_topic, $contact['poll']) && !link_compare($hub_topic2, $contact['poll'])) {
  91                         logger('Hub topic ' . $hub_topic . ' != ' . $contact['poll']);
  92                         System::httpExit(404);
  93                 }
  94
  95                 // do subscriber verification according to the PuSH protocol
  96                 $hub_challenge = random_string(40);
  97                 $params = 'hub.mode=' .
  98                         ($subscribe == 1 ? 'subscribe' : 'unsubscribe') .
  99                         '&hub.topic=' . urlencode($hub_topic) .
 100                         '&hub.challenge=' . $hub_challenge .
 101                         '&hub.lease_seconds=604800' .
 102                         '&hub.verify_token=' . $hub_verify_token;
 103
 104                 // lease time is hard coded to one week (in seconds)
 105                 // we don't actually enforce the lease time because GNU
 106                 // Social/StatusNet doesn't honour it (yet)
 107
 108                 $body = Network::fetchUrl($hub_callback . "?" . $params);
 109                 $ret = $a->get_curl_code();
 110
 111                 // give up if the HTTP return code wasn't a success (2xx)
 112                 if ($ret < 200 || $ret > 299) {
 113                         logger("Subscriber verification for $hub_topic at $hub_callback returned $ret, ignoring.");
 114                         System::httpExit(404);
 115                 }
 116
 117                 // check that the correct hub_challenge code was echoed back
 118                 if (trim($body) !== $hub_challenge) {
 119                         logger("Subscriber did not echo back hub.challenge, ignoring.");
 120                         logger("\"$hub_challenge\" != \"".trim($body)."\"");
 121                         System::httpExit(404);
 122                 }
 123
 124                 PushSubscriber::renew($owner['uid'], $nick, $subscribe, $hub_callback, $hub_topic, $hub_secret);
 125
 126                 System::httpExit(202);
 127         }
 128         killme();
 129 }