mod/pubsubhubbub.php

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