mod/pubsubhubbub.php

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