mod/pubsubhubbub.php

   1 <?php
   2
   3 if(! function_exists('post_var')) {
   4 function post_var($name) {
   5         return (x($_POST, $name)) ? notags(trim($_POST[$name])) : '';
   6 }
   7 }
   8
   9 if(! function_exists('pubsubhubbub_init')) {
  10 function pubsubhubbub_init(&$a) {
  11         // PuSH subscription must be considered "public" so just block it
  12         // if public access isn't enabled.
  13         if (get_config('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                         $subscribe = 1;
  38                 } else if ($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
  49                 $nick = substr(strrchr($hub_topic, "/"), 1);
  50
  51                 if (!$nick) {
  52                         logger('pubsubhubbub: bad hub_topic=$hub_topic, ignoring.');
  53                         http_status_exit(404);
  54                 }
  55
  56                 // fetch user from database given the nickname
  57                 $r = q("SELECT * FROM `user` WHERE `nickname` = '%s'" .
  58                            " AND `account_expired` = 0 AND `account_removed` = 0 LIMIT 1",
  59                            dbesc($nick));
  60
  61                 if(!count($r)) {
  62                         logger('pubsubhubbub: local account not found: ' . $nick);
  63                         http_status_exit(404);
  64                 }
  65
  66                 $owner = $r[0];
  67
  68                 // abort if user's wall is supposed to be private
  69                 if ($r[0]['hidewall']) {
  70                         logger('pubsubhubbub: local user ' . $nick .
  71                                    'has chosen to hide wall, ignoring.');
  72                         http_status_exit(403);
  73                 }
  74
  75                 // get corresponding row from contact table
  76                 $r = q("SELECT * FROM `contact` WHERE `uid` = %d AND NOT `blocked`".
  77                            " AND NOT `pending` AND `self` LIMIT 1",
  78                            intval($owner['uid']));
  79                 if(!count($r)) {
  80                         logger('pubsubhubbub: contact not found.');
  81                         http_status_exit(404);
  82                 }
  83
  84                 $contact = $r[0];
  85
  86                 // sanity check that topic URLs are the same
  87                 if(!link_compare($hub_topic, $contact['poll'])) {
  88                         logger('pubsubhubbub: hub topic ' . $hub_topic . ' != ' .
  89                                    $contact['poll']);
  90                         http_status_exit(404);
  91                 }
  92
  93                 // do subscriber verification according to the PuSH protocol
  94                 $hub_challenge = random_string(40);
  95                 $params = 'hub.mode=' .
  96                         ($subscribe == 1 ? 'subscribe' : 'unsubscribe') .
  97                         '&hub.topic=' . urlencode($hub_topic) .
  98                         '&hub.challenge=' . $hub_challenge .
  99                         '&hub.lease_seconds=604800' .
 100                         '&hub.verify_token=' . $hub_verify_token;
 101
 102                 // lease time is hard coded to one week (in seconds)
 103                 // we don't actually enforce the lease time because GNU
 104                 // Social/StatusNet doesn't honour it (yet)
 105
 106                 $body = fetch_url($hub_callback . "?" . $params);
 107                 $ret = $a->get_curl_code();
 108
 109                 // give up if the HTTP return code wasn't a success (2xx)
 110                 if ($ret < 200 || $ret > 299) {
 111                         logger("pubsubhubbub: subscriber verification at $hub_callback ".
 112                                    "returned $ret, ignoring.");
 113                         http_status_exit(404);
 114                 }
 115
 116                 // check that the correct hub_challenge code was echoed back
 117                 if (trim($body) !== $hub_challenge) {
 118                         logger("pubsubhubbub: subscriber did not echo back ".
 119                                    "hub.challenge, ignoring.");
 120                         logger("\"$hub_challenge\" != \"".trim($body)."\"");
 121                         http_status_exit(404);
 122                 }
 123
 124                 // fetch the old subscription if it exists
 125                 $r = q("SELECT * FROM `push_subscriber` WHERE `callback_url` = '%s'",
 126                   dbesc($hub_callback));
 127
 128                 // delete old subscription if it exists
 129                 q("DELETE FROM `push_subscriber` WHERE `callback_url` = '%s'",
 130                   dbesc($hub_callback));
 131
 132                 if ($subscribe) {
 133                         $last_update = datetime_convert('UTC','UTC','now','Y-m-d H:i:s');
 134                         $push_flag = 0;
 135
 136                         // if we are just updating an old subscription, keep the
 137                         // old values for push and last_update
 138                         if (count($r)) {
 139                                 $last_update = $r[0]['last_update'];
 140                                 $push_flag = $r[0]['push'];
 141                         }
 142
 143                         // subscribe means adding the row to the table
 144                         q("INSERT INTO `push_subscriber` (`uid`, `callback_url`, " .
 145                           "`topic`, `nickname`, `push`, `last_update`, `secret`) values " .
 146                           "(%d, '%s', '%s', '%s', %d, '%s', '%s')",
 147                           intval($owner['uid']),
 148                           dbesc($hub_callback),
 149                           dbesc($hub_topic),
 150                           dbesc($nick),
 151                           intval($push_flag),
 152                           dbesc($last_update),
 153                           dbesc($hub_secret));
 154                         logger("pubsubhubbub: successfully subscribed [$hub_callback].");
 155                 } else {
 156                         logger("pubsubhubbub: successfully unsubscribed [$hub_callback].");
 157                         // we do nothing here, since the row was already deleted
 158                 }
 159                 http_status_exit(202);
 160         }
 161
 162         killme();
 163 }
 164 }
 165 ?>