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