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                         $subscribe = 1;
  37                 } elseif ($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 as a fallback
  48                 $nick = substr(strrchr($hub_topic, "/"), 1);
  49
  50                 // Normally the url should now contain the nick name as last part of the url
  51                 if ($a->argc > 1) {
  52                         $nick = $a->argv[1];
  53                 }
  54
  55                 if (!$nick) {
  56                         logger('pubsubhubbub: bad hub_topic=$hub_topic, ignoring.');
  57                         http_status_exit(404);
  58                 }
  59
  60                 // fetch user from database given the nickname
  61                 $r = q("SELECT * FROM `user` WHERE `nickname` = '%s'" .
  62                            " AND `account_expired` = 0 AND `account_removed` = 0 LIMIT 1",
  63                            dbesc($nick));
  64
  65                 if (!dbm::is_result($r)) {
  66                         logger('pubsubhubbub: local account not found: ' . $nick);
  67                         http_status_exit(404);
  68                 }
  69
  70                 $owner = $r[0];
  71
  72                 // abort if user's wall is supposed to be private
  73                 if ($r[0]['hidewall']) {
  74                         logger('pubsubhubbub: local user ' . $nick .
  75                                    'has chosen to hide wall, ignoring.');
  76                         http_status_exit(403);
  77                 }
  78
  79                 // get corresponding row from contact table
  80                 $r = q("SELECT * FROM `contact` WHERE `uid` = %d AND NOT `blocked`".
  81                            " AND NOT `pending` AND `self` LIMIT 1",
  82                            intval($owner['uid']));
  83                 if (!dbm::is_result($r)) {
  84                         logger('pubsubhubbub: contact not found.');
  85                         http_status_exit(404);
  86                 }
  87
  88                 $contact = $r[0];
  89
  90                 // sanity check that topic URLs are the same
  91                 if (!link_compare($hub_topic, $contact['poll'])) {
  92                         logger('pubsubhubbub: hub topic ' . $hub_topic . ' != ' .
  93                                    $contact['poll']);
  94                         http_status_exit(404);
  95                 }
  96
  97                 // do subscriber verification according to the PuSH protocol
  98                 $hub_challenge = random_string(40);
  99                 $params = 'hub.mode=' .
 100                         ($subscribe == 1 ? 'subscribe' : 'unsubscribe') .
 101                         '&hub.topic=' . urlencode($hub_topic) .
 102                         '&hub.challenge=' . $hub_challenge .
 103                         '&hub.lease_seconds=604800' .
 104                         '&hub.verify_token=' . $hub_verify_token;
 105
 106                 // lease time is hard coded to one week (in seconds)
 107                 // we don't actually enforce the lease time because GNU
 108                 // Social/StatusNet doesn't honour it (yet)
 109
 110                 $body = fetch_url($hub_callback . "?" . $params);
 111                 $ret = $a->get_curl_code();
 112
 113                 // give up if the HTTP return code wasn't a success (2xx)
 114                 if ($ret < 200 || $ret > 299) {
 115                         logger("pubsubhubbub: subscriber verification at $hub_callback ".
 116                                    "returned $ret, ignoring.");
 117                         http_status_exit(404);
 118                 }
 119
 120                 // check that the correct hub_challenge code was echoed back
 121                 if (trim($body) !== $hub_challenge) {
 122                         logger("pubsubhubbub: subscriber did not echo back ".
 123                                    "hub.challenge, ignoring.");
 124                         logger("\"$hub_challenge\" != \"".trim($body)."\"");
 125                         http_status_exit(404);
 126                 }
 127
 128                 // fetch the old subscription if it exists
 129                 $r = q("SELECT * FROM `push_subscriber` WHERE `callback_url` = '%s'",
 130                   dbesc($hub_callback));
 131
 132                 // delete old subscription if it exists
 133                 q("DELETE FROM `push_subscriber` WHERE `callback_url` = '%s'",
 134                   dbesc($hub_callback));
 135
 136                 if ($subscribe) {
 137                         $last_update = datetime_convert('UTC','UTC','now','Y-m-d H:i:s');
 138                         $push_flag = 0;
 139
 140                         // if we are just updating an old subscription, keep the
 141                         // old values for push and last_update
 142                         if (dbm::is_result($r)) {
 143                                 $last_update = $r[0]['last_update'];
 144                                 $push_flag = $r[0]['push'];
 145                         }
 146
 147                         // subscribe means adding the row to the table
 148                         q("INSERT INTO `push_subscriber` (`uid`, `callback_url`, " .
 149                           "`topic`, `nickname`, `push`, `last_update`, `secret`) values " .
 150                           "(%d, '%s', '%s', '%s', %d, '%s', '%s')",
 151                           intval($owner['uid']),
 152                           dbesc($hub_callback),
 153                           dbesc($hub_topic),
 154                           dbesc($nick),
 155                           intval($push_flag),
 156                           dbesc($last_update),
 157                           dbesc($hub_secret));
 158                         logger("pubsubhubbub: successfully subscribed [$hub_callback].");
 159                 } else {
 160                         logger("pubsubhubbub: successfully unsubscribed [$hub_callback].");
 161                         // we do nothing here, since the row was already deleted
 162                 }
 163                 http_status_exit(202);
 164         }
 165
 166         killme();
 167 }