mod/pubsubhubbub.php

   1 <?php
   2
   3 use Friendica\App;
   4 use Friendica\Core\Config;
   5 use Friendica\Database\DBM;
   6
   7 function post_var($name) {
   8         return (x($_POST, $name)) ? notags(trim($_POST[$name])) : '';
   9 }
  10
  11 function pubsubhubbub_init(App $a) {
  12         // PuSH subscription must be considered "public" so just block it
  13         // if public access isn't enabled.
  14         if (Config::get('system', 'block_public')) {
  15                 http_status_exit(403);
  16         }
  17
  18         // Subscription request from subscriber
  19         // https://pubsubhubbub.googlecode.com/git/pubsubhubbub-core-0.4.html#anchor4
  20         // Example from GNU Social:
  21         // [hub_mode] => subscribe
  22         // [hub_callback] => http://status.local/main/push/callback/1
  23         // [hub_verify] => sync
  24         // [hub_verify_token] => af11...
  25         // [hub_secret] => af11...
  26         // [hub_topic] => http://friendica.local/dfrn_poll/sazius
  27
  28         if ($_SERVER['REQUEST_METHOD'] === 'POST') {
  29                 $hub_mode = post_var('hub_mode');
  30                 $hub_callback = post_var('hub_callback');
  31                 $hub_verify = post_var('hub_verify');
  32                 $hub_verify_token = post_var('hub_verify_token');
  33                 $hub_secret = post_var('hub_secret');
  34                 $hub_topic = post_var('hub_topic');
  35
  36                 // check for valid hub_mode
  37                 if ($hub_mode === 'subscribe') {
  38                         $subscribe = 1;
  39                 } elseif ($hub_mode === 'unsubscribe') {
  40                         $subscribe = 0;
  41                 } else {
  42                         logger("pubsubhubbub: invalid hub_mode=$hub_mode, ignoring.");
  43                         http_status_exit(404);
  44                 }
  45
  46                 logger("pubsubhubbub: $hub_mode request from " .
  47                            $_SERVER['REMOTE_ADDR']);
  48
  49                 // get the nick name from the topic, a bit hacky but needed as a fallback
  50                 $nick = substr(strrchr($hub_topic, "/"), 1);
  51
  52                 // Normally the url should now contain the nick name as last part of the url
  53                 if ($a->argc > 1) {
  54                         $nick = $a->argv[1];
  55                 }
  56
  57                 if (!$nick) {
  58                         logger('pubsubhubbub: bad hub_topic=$hub_topic, ignoring.');
  59                         http_status_exit(404);
  60                 }
  61
  62                 // fetch user from database given the nickname
  63                 $r = q("SELECT * FROM `user` WHERE `nickname` = '%s'" .
  64                            " AND `account_expired` = 0 AND `account_removed` = 0 LIMIT 1",
  65                            dbesc($nick));
  66
  67                 if (!DBM::is_result($r)) {
  68                         logger('pubsubhubbub: local account not found: ' . $nick);
  69                         http_status_exit(404);
  70                 }
  71
  72                 $owner = $r[0];
  73
  74                 // abort if user's wall is supposed to be private
  75                 if ($r[0]['hidewall']) {
  76                         logger('pubsubhubbub: local user ' . $nick .
  77                                    'has chosen to hide wall, ignoring.');
  78                         http_status_exit(403);
  79                 }
  80
  81                 // get corresponding row from contact table
  82                 $r = q("SELECT * FROM `contact` WHERE `uid` = %d AND NOT `blocked`".
  83                            " AND NOT `pending` AND `self` LIMIT 1",
  84                            intval($owner['uid']));
  85                 if (!DBM::is_result($r)) {
  86                         logger('pubsubhubbub: contact not found.');
  87                         http_status_exit(404);
  88                 }
  89
  90                 $contact = $r[0];
  91
  92                 // sanity check that topic URLs are the same
  93                 if (!link_compare($hub_topic, $contact['poll'])) {
  94                         logger('pubsubhubbub: hub topic ' . $hub_topic . ' != ' .
  95                                    $contact['poll']);
  96                         http_status_exit(404);
  97                 }
  98
  99                 // do subscriber verification according to the PuSH protocol
 100                 $hub_challenge = random_string(40);
 101                 $params = 'hub.mode=' .
 102                         ($subscribe == 1 ? 'subscribe' : 'unsubscribe') .
 103                         '&hub.topic=' . urlencode($hub_topic) .
 104                         '&hub.challenge=' . $hub_challenge .
 105                         '&hub.lease_seconds=604800' .
 106                         '&hub.verify_token=' . $hub_verify_token;
 107
 108                 // lease time is hard coded to one week (in seconds)
 109                 // we don't actually enforce the lease time because GNU
 110                 // Social/StatusNet doesn't honour it (yet)
 111
 112                 $body = fetch_url($hub_callback . "?" . $params);
 113                 $ret = $a->get_curl_code();
 114
 115                 // give up if the HTTP return code wasn't a success (2xx)
 116                 if ($ret < 200 || $ret > 299) {
 117                         logger("pubsubhubbub: subscriber verification at $hub_callback ".
 118                                    "returned $ret, ignoring.");
 119                         http_status_exit(404);
 120                 }
 121
 122                 // check that the correct hub_challenge code was echoed back
 123                 if (trim($body) !== $hub_challenge) {
 124                         logger("pubsubhubbub: subscriber did not echo back ".
 125                                    "hub.challenge, ignoring.");
 126                         logger("\"$hub_challenge\" != \"".trim($body)."\"");
 127                         http_status_exit(404);
 128                 }
 129
 130                 // fetch the old subscription if it exists
 131                 $r = q("SELECT * FROM `push_subscriber` WHERE `callback_url` = '%s'",
 132                   dbesc($hub_callback));
 133
 134                 // delete old subscription if it exists
 135                 q("DELETE FROM `push_subscriber` WHERE `callback_url` = '%s'",
 136                   dbesc($hub_callback));
 137
 138                 if ($subscribe) {
 139                         $last_update = datetime_convert('UTC','UTC','now','Y-m-d H:i:s');
 140                         $push_flag = 0;
 141
 142                         // if we are just updating an old subscription, keep the
 143                         // old values for push and last_update
 144                         if (DBM::is_result($r)) {
 145                                 $last_update = $r[0]['last_update'];
 146                                 $push_flag = $r[0]['push'];
 147                         }
 148
 149                         // subscribe means adding the row to the table
 150                         q("INSERT INTO `push_subscriber` (`uid`, `callback_url`, " .
 151                           "`topic`, `nickname`, `push`, `last_update`, `secret`) values " .
 152                           "(%d, '%s', '%s', '%s', %d, '%s', '%s')",
 153                           intval($owner['uid']),
 154                           dbesc($hub_callback),
 155                           dbesc($hub_topic),
 156                           dbesc($nick),
 157                           intval($push_flag),
 158                           dbesc($last_update),
 159                           dbesc($hub_secret));
 160                         logger("pubsubhubbub: successfully subscribed [$hub_callback].");
 161                 } else {
 162                         logger("pubsubhubbub: successfully unsubscribed [$hub_callback].");
 163                         // we do nothing here, since the row was already deleted
 164                 }
 165                 http_status_exit(202);
 166         }
 167
 168         killme();
 169 }