mod/pubsubhubbub.php

   1 <?php
   2
   3 use Friendica\App;
   4 use Friendica\Core\Config;
   5 use Friendica\Core\System;
   6 use Friendica\Database\DBM;
   7 use Friendica\Util\DateTimeFormat;
   8 use Friendica\Util\Network;
   9
  10 function post_var($name) {
  11         return (x($_POST, $name)) ? notags(trim($_POST[$name])) : '';
  12 }
  13
  14 function pubsubhubbub_init(App $a) {
  15         // PuSH subscription must be considered "public" so just block it
  16         // if public access isn't enabled.
  17         if (Config::get('system', 'block_public')) {
  18                 System::httpExit(403);
  19         }
  20
  21         // Subscription request from subscriber
  22         // https://pubsubhubbub.googlecode.com/git/pubsubhubbub-core-0.4.html#anchor4
  23         // Example from GNU Social:
  24         // [hub_mode] => subscribe
  25         // [hub_callback] => http://status.local/main/push/callback/1
  26         // [hub_verify] => sync
  27         // [hub_verify_token] => af11...
  28         // [hub_secret] => af11...
  29         // [hub_topic] => http://friendica.local/dfrn_poll/sazius
  30
  31         if ($_SERVER['REQUEST_METHOD'] === 'POST') {
  32                 $hub_mode = post_var('hub_mode');
  33                 $hub_callback = post_var('hub_callback');
  34                 $hub_verify = post_var('hub_verify');
  35                 $hub_verify_token = post_var('hub_verify_token');
  36                 $hub_secret = post_var('hub_secret');
  37                 $hub_topic = post_var('hub_topic');
  38
  39                 // check for valid hub_mode
  40                 if ($hub_mode === 'subscribe') {
  41                         $subscribe = 1;
  42                 } elseif ($hub_mode === 'unsubscribe') {
  43                         $subscribe = 0;
  44                 } else {
  45                         logger("pubsubhubbub: invalid hub_mode=$hub_mode, ignoring.");
  46                         System::httpExit(404);
  47                 }
  48
  49                 logger("pubsubhubbub: $hub_mode request from " .
  50                            $_SERVER['REMOTE_ADDR']);
  51
  52                 // get the nick name from the topic, a bit hacky but needed as a fallback
  53                 $nick = substr(strrchr($hub_topic, "/"), 1);
  54
  55                 // Normally the url should now contain the nick name as last part of the url
  56                 if ($a->argc > 1) {
  57                         $nick = $a->argv[1];
  58                 }
  59
  60                 if (!$nick) {
  61                         logger('pubsubhubbub: bad hub_topic=$hub_topic, ignoring.');
  62                         System::httpExit(404);
  63                 }
  64
  65                 // fetch user from database given the nickname
  66                 $r = q("SELECT * FROM `user` WHERE `nickname` = '%s'" .
  67                            " AND `account_expired` = 0 AND `account_removed` = 0 LIMIT 1",
  68                            dbesc($nick));
  69
  70                 if (!DBM::is_result($r)) {
  71                         logger('pubsubhubbub: local account not found: ' . $nick);
  72                         System::httpExit(404);
  73                 }
  74
  75                 $owner = $r[0];
  76
  77                 // abort if user's wall is supposed to be private
  78                 if ($r[0]['hidewall']) {
  79                         logger('pubsubhubbub: local user ' . $nick .
  80                                    'has chosen to hide wall, ignoring.');
  81                         System::httpExit(403);
  82                 }
  83
  84                 // get corresponding row from contact table
  85                 $r = q("SELECT * FROM `contact` WHERE `uid` = %d AND NOT `blocked`".
  86                            " AND NOT `pending` AND `self` LIMIT 1",
  87                            intval($owner['uid']));
  88                 if (!DBM::is_result($r)) {
  89                         logger('pubsubhubbub: contact not found.');
  90                         System::httpExit(404);
  91                 }
  92
  93                 $contact = $r[0];
  94
  95                 // sanity check that topic URLs are the same
  96                 if (!link_compare($hub_topic, $contact['poll'])) {
  97                         logger('pubsubhubbub: hub topic ' . $hub_topic . ' != ' .
  98                                    $contact['poll']);
  99                         System::httpExit(404);
 100                 }
 101
 102                 // do subscriber verification according to the PuSH protocol
 103                 $hub_challenge = random_string(40);
 104                 $params = 'hub.mode=' .
 105                         ($subscribe == 1 ? 'subscribe' : 'unsubscribe') .
 106                         '&hub.topic=' . urlencode($hub_topic) .
 107                         '&hub.challenge=' . $hub_challenge .
 108                         '&hub.lease_seconds=604800' .
 109                         '&hub.verify_token=' . $hub_verify_token;
 110
 111                 // lease time is hard coded to one week (in seconds)
 112                 // we don't actually enforce the lease time because GNU
 113                 // Social/StatusNet doesn't honour it (yet)
 114
 115                 $body = Network::fetchUrl($hub_callback . "?" . $params);
 116                 $ret = $a->get_curl_code();
 117
 118                 // give up if the HTTP return code wasn't a success (2xx)
 119                 if ($ret < 200 || $ret > 299) {
 120                         logger("pubsubhubbub: subscriber verification at $hub_callback ".
 121                                    "returned $ret, ignoring.");
 122                         System::httpExit(404);
 123                 }
 124
 125                 // check that the correct hub_challenge code was echoed back
 126                 if (trim($body) !== $hub_challenge) {
 127                         logger("pubsubhubbub: subscriber did not echo back ".
 128                                    "hub.challenge, ignoring.");
 129                         logger("\"$hub_challenge\" != \"".trim($body)."\"");
 130                         System::httpExit(404);
 131                 }
 132
 133                 // fetch the old subscription if it exists
 134                 $r = q("SELECT * FROM `push_subscriber` WHERE `callback_url` = '%s'",
 135                   dbesc($hub_callback));
 136
 137                 // delete old subscription if it exists
 138                 q("DELETE FROM `push_subscriber` WHERE `callback_url` = '%s'",
 139                   dbesc($hub_callback));
 140
 141                 if ($subscribe) {
 142                         $last_update = DateTimeFormat::utcNow();
 143                         $push_flag = 0;
 144
 145                         // if we are just updating an old subscription, keep the
 146                         // old values for push and last_update
 147                         if (DBM::is_result($r)) {
 148                                 $last_update = $r[0]['last_update'];
 149                                 $push_flag = $r[0]['push'];
 150                         }
 151
 152                         // subscribe means adding the row to the table
 153                         q("INSERT INTO `push_subscriber` (`uid`, `callback_url`, " .
 154                           "`topic`, `nickname`, `push`, `last_update`, `secret`) values " .
 155                           "(%d, '%s', '%s', '%s', %d, '%s', '%s')",
 156                           intval($owner['uid']),
 157                           dbesc($hub_callback),
 158                           dbesc($hub_topic),
 159                           dbesc($nick),
 160                           intval($push_flag),
 161                           dbesc($last_update),
 162                           dbesc($hub_secret));
 163                         logger("pubsubhubbub: successfully subscribed [$hub_callback].");
 164                 } else {
 165                         logger("pubsubhubbub: successfully unsubscribed [$hub_callback].");
 166                         // we do nothing here, since the row was already deleted
 167                 }
 168                 System::httpExit(202);
 169         }
 170
 171         killme();
 172 }