mod/pubsubhubbub.php

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