mod/pubsubhubbub.php

   1 <?php
   2
   3 use Friendica\App;
   4 use Friendica\Core\Config;
   5 use Friendica\Database\DBM;
   6 use Friendica\Util\Network;
   7
   8 function post_var($name) {
   9         return (x($_POST, $name)) ? notags(trim($_POST[$name])) : '';
  10 }
  11
  12 function pubsubhubbub_init(App $a) {
  13         // PuSH subscription must be considered "public" so just block it
  14         // if public access isn't enabled.
  15         if (Config::get('system', 'block_public')) {
  16                 Network::httpStatusExit(403);
  17         }
  18
  19         // Subscription request from subscriber
  20         // https://pubsubhubbub.googlecode.com/git/pubsubhubbub-core-0.4.html#anchor4
  21         // Example from GNU Social:
  22         // [hub_mode] => subscribe
  23         // [hub_callback] => http://status.local/main/push/callback/1
  24         // [hub_verify] => sync
  25         // [hub_verify_token] => af11...
  26         // [hub_secret] => af11...
  27         // [hub_topic] => http://friendica.local/dfrn_poll/sazius
  28
  29         if ($_SERVER['REQUEST_METHOD'] === 'POST') {
  30                 $hub_mode = post_var('hub_mode');
  31                 $hub_callback = post_var('hub_callback');
  32                 $hub_verify = post_var('hub_verify');
  33                 $hub_verify_token = post_var('hub_verify_token');
  34                 $hub_secret = post_var('hub_secret');
  35                 $hub_topic = post_var('hub_topic');
  36
  37                 // check for valid hub_mode
  38                 if ($hub_mode === 'subscribe') {
  39                         $subscribe = 1;
  40                 } elseif ($hub_mode === 'unsubscribe') {
  41                         $subscribe = 0;
  42                 } else {
  43                         logger("pubsubhubbub: invalid hub_mode=$hub_mode, ignoring.");
  44                         Network::httpStatusExit(404);
  45                 }
  46
  47                 logger("pubsubhubbub: $hub_mode request from " .
  48                            $_SERVER['REMOTE_ADDR']);
  49
  50                 // get the nick name from the topic, a bit hacky but needed as a fallback
  51                 $nick = substr(strrchr($hub_topic, "/"), 1);
  52
  53                 // Normally the url should now contain the nick name as last part of the url
  54                 if ($a->argc > 1) {
  55                         $nick = $a->argv[1];
  56                 }
  57
  58                 if (!$nick) {
  59                         logger('pubsubhubbub: bad hub_topic=$hub_topic, ignoring.');
  60                         Network::httpStatusExit(404);
  61                 }
  62
  63                 // fetch user from database given the nickname
  64                 $r = q("SELECT * FROM `user` WHERE `nickname` = '%s'" .
  65                            " AND `account_expired` = 0 AND `account_removed` = 0 LIMIT 1",
  66                            dbesc($nick));
  67
  68                 if (!DBM::is_result($r)) {
  69                         logger('pubsubhubbub: local account not found: ' . $nick);
  70                         Network::httpStatusExit(404);
  71                 }
  72
  73                 $owner = $r[0];
  74
  75                 // abort if user's wall is supposed to be private
  76                 if ($r[0]['hidewall']) {
  77                         logger('pubsubhubbub: local user ' . $nick .
  78                                    'has chosen to hide wall, ignoring.');
  79                         Network::httpStatusExit(403);
  80                 }
  81
  82                 // get corresponding row from contact table
  83                 $r = q("SELECT * FROM `contact` WHERE `uid` = %d AND NOT `blocked`".
  84                            " AND NOT `pending` AND `self` LIMIT 1",
  85                            intval($owner['uid']));
  86                 if (!DBM::is_result($r)) {
  87                         logger('pubsubhubbub: contact not found.');
  88                         Network::httpStatusExit(404);
  89                 }
  90
  91                 $contact = $r[0];
  92
  93                 // sanity check that topic URLs are the same
  94                 if (!link_compare($hub_topic, $contact['poll'])) {
  95                         logger('pubsubhubbub: hub topic ' . $hub_topic . ' != ' .
  96                                    $contact['poll']);
  97                         Network::httpStatusExit(404);
  98                 }
  99
 100                 // do subscriber verification according to the PuSH protocol
 101                 $hub_challenge = random_string(40);
 102                 $params = 'hub.mode=' .
 103                         ($subscribe == 1 ? 'subscribe' : 'unsubscribe') .
 104                         '&hub.topic=' . urlencode($hub_topic) .
 105                         '&hub.challenge=' . $hub_challenge .
 106                         '&hub.lease_seconds=604800' .
 107                         '&hub.verify_token=' . $hub_verify_token;
 108
 109                 // lease time is hard coded to one week (in seconds)
 110                 // we don't actually enforce the lease time because GNU
 111                 // Social/StatusNet doesn't honour it (yet)
 112
 113                 $body = Network::fetchURL($hub_callback . "?" . $params);
 114                 $ret = $a->get_curl_code();
 115
 116                 // give up if the HTTP return code wasn't a success (2xx)
 117                 if ($ret < 200 || $ret > 299) {
 118                         logger("pubsubhubbub: subscriber verification at $hub_callback ".
 119                                    "returned $ret, ignoring.");
 120                         Network::httpStatusExit(404);
 121                 }
 122
 123                 // check that the correct hub_challenge code was echoed back
 124                 if (trim($body) !== $hub_challenge) {
 125                         logger("pubsubhubbub: subscriber did not echo back ".
 126                                    "hub.challenge, ignoring.");
 127                         logger("\"$hub_challenge\" != \"".trim($body)."\"");
 128                         Network::httpStatusExit(404);
 129                 }
 130
 131                 // fetch the old subscription if it exists
 132                 $r = q("SELECT * FROM `push_subscriber` WHERE `callback_url` = '%s'",
 133                   dbesc($hub_callback));
 134
 135                 // delete old subscription if it exists
 136                 q("DELETE FROM `push_subscriber` WHERE `callback_url` = '%s'",
 137                   dbesc($hub_callback));
 138
 139                 if ($subscribe) {
 140                         $last_update = datetime_convert('UTC','UTC','now','Y-m-d H:i:s');
 141                         $push_flag = 0;
 142
 143                         // if we are just updating an old subscription, keep the
 144                         // old values for push and last_update
 145                         if (DBM::is_result($r)) {
 146                                 $last_update = $r[0]['last_update'];
 147                                 $push_flag = $r[0]['push'];
 148                         }
 149
 150                         // subscribe means adding the row to the table
 151                         q("INSERT INTO `push_subscriber` (`uid`, `callback_url`, " .
 152                           "`topic`, `nickname`, `push`, `last_update`, `secret`) values " .
 153                           "(%d, '%s', '%s', '%s', %d, '%s', '%s')",
 154                           intval($owner['uid']),
 155                           dbesc($hub_callback),
 156                           dbesc($hub_topic),
 157                           dbesc($nick),
 158                           intval($push_flag),
 159                           dbesc($last_update),
 160                           dbesc($hub_secret));
 161                         logger("pubsubhubbub: successfully subscribed [$hub_callback].");
 162                 } else {
 163                         logger("pubsubhubbub: successfully unsubscribed [$hub_callback].");
 164                         // we do nothing here, since the row was already deleted
 165                 }
 166                 Network::httpStatusExit(202);
 167         }
 168
 169         killme();
 170 }