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