mod/pubsubhubbub.php

   1 <?php
   2
   3 use Friendica\App;
   4 use Friendica\Core\Config;
   5 use Friendica\Core\Logger;
   6 use Friendica\Core\System;
   7 use Friendica\Database\DBA;
   8 use Friendica\Model\PushSubscriber;
   9 use Friendica\Util\Network;
  10 use Friendica\Util\Strings;
  11
  12 function post_var($name) {
  13         return (x($_POST, $name)) ? Strings::removeTags(trim($_POST[$name])) : '';
  14 }
  15
  16 function pubsubhubbub_init(App $a) {
  17         // PuSH subscription must be considered "public" so just block it
  18         // if public access isn't enabled.
  19         if (Config::get('system', 'block_public')) {
  20                 System::httpExit(403);
  21         }
  22
  23         // Subscription request from subscriber
  24         // https://pubsubhubbub.googlecode.com/git/pubsubhubbub-core-0.4.html#anchor4
  25         // Example from GNU Social:
  26         // [hub_mode] => subscribe
  27         // [hub_callback] => http://status.local/main/push/callback/1
  28         // [hub_verify] => sync
  29         // [hub_verify_token] => af11...
  30         // [hub_secret] => af11...
  31         // [hub_topic] => http://friendica.local/dfrn_poll/sazius
  32
  33         if ($_SERVER['REQUEST_METHOD'] === 'POST') {
  34                 $hub_mode = post_var('hub_mode');
  35                 $hub_callback = post_var('hub_callback');
  36                 $hub_verify = post_var('hub_verify');
  37                 $hub_verify_token = post_var('hub_verify_token');
  38                 $hub_secret = post_var('hub_secret');
  39                 $hub_topic = post_var('hub_topic');
  40
  41                 // check for valid hub_mode
  42                 if ($hub_mode === 'subscribe') {
  43                         $subscribe = 1;
  44                 } elseif ($hub_mode === 'unsubscribe') {
  45                         $subscribe = 0;
  46                 } else {
  47                         Logger::log("Invalid hub_mode=$hub_mode, ignoring.");
  48                         System::httpExit(404);
  49                 }
  50
  51                 Logger::log("$hub_mode request from " . $_SERVER['REMOTE_ADDR']);
  52
  53                 // get the nick name from the topic, a bit hacky but needed as a fallback
  54                 $nick = substr(strrchr($hub_topic, "/"), 1);
  55
  56                 // Normally the url should now contain the nick name as last part of the url
  57                 if ($a->argc > 1) {
  58                         $nick = $a->argv[1];
  59                 }
  60
  61                 if (!$nick) {
  62                         Logger::log('Bad hub_topic=$hub_topic, ignoring.');
  63                         System::httpExit(404);
  64                 }
  65
  66                 // fetch user from database given the nickname
  67                 $condition = ['nickname' => $nick, 'account_expired' => false, 'account_removed' => false];
  68                 $owner = DBA::selectFirst('user', ['uid', 'hidewall'], $condition);
  69                 if (!DBA::isResult($owner)) {
  70                         Logger::log('Local account not found: ' . $nick . ' - topic: ' . $hub_topic . ' - callback: ' . $hub_callback);
  71                         System::httpExit(404);
  72                 }
  73
  74                 // abort if user's wall is supposed to be private
  75                 if ($owner['hidewall']) {
  76                         Logger::log('Local user ' . $nick . 'has chosen to hide wall, ignoring.');
  77                         System::httpExit(403);
  78                 }
  79
  80                 // get corresponding row from contact table
  81                 $condition = ['uid' => $owner['uid'], 'blocked' => false,
  82                         'pending' => false, 'self' => true];
  83                 $contact = DBA::selectFirst('contact', ['poll'], $condition);
  84                 if (!DBA::isResult($contact)) {
  85                         Logger::log('Self contact for user ' . $owner['uid'] . ' not found.');
  86                         System::httpExit(404);
  87                 }
  88
  89                 // sanity check that topic URLs are the same
  90                 $hub_topic2 = str_replace('/feed/', '/dfrn_poll/', $hub_topic);
  91                 if (!link_compare($hub_topic, $contact['poll']) && !link_compare($hub_topic2, $contact['poll'])) {
  92                         Logger::log('Hub topic ' . $hub_topic . ' != ' . $contact['poll']);
  93                         System::httpExit(404);
  94                 }
  95
  96                 // do subscriber verification according to the PuSH protocol
  97                 $hub_challenge = Strings::getRandomHex(40);
  98                 $params = 'hub.mode=' .
  99                         ($subscribe == 1 ? 'subscribe' : 'unsubscribe') .
 100                         '&hub.topic=' . urlencode($hub_topic) .
 101                         '&hub.challenge=' . $hub_challenge .
 102                         '&hub.lease_seconds=604800' .
 103                         '&hub.verify_token=' . $hub_verify_token;
 104
 105                 // lease time is hard coded to one week (in seconds)
 106                 // we don't actually enforce the lease time because GNU
 107                 // Social/StatusNet doesn't honour it (yet)
 108
 109                 $fetchResult = Network::fetchUrlFull($hub_callback . "?" . $params);
 110                 $body = $fetchResult->getBody();
 111                 $ret = $fetchResult->getReturnCode();
 112
 113                 // give up if the HTTP return code wasn't a success (2xx)
 114                 if ($ret < 200 || $ret > 299) {
 115                         Logger::log("Subscriber verification for $hub_topic at $hub_callback returned $ret, ignoring.");
 116                         System::httpExit(404);
 117                 }
 118
 119                 // check that the correct hub_challenge code was echoed back
 120                 if (trim($body) !== $hub_challenge) {
 121                         Logger::log("Subscriber did not echo back hub.challenge, ignoring.");
 122                         Logger::log("\"$hub_challenge\" != \"".trim($body)."\"");
 123                         System::httpExit(404);
 124                 }
 125
 126                 PushSubscriber::renew($owner['uid'], $nick, $subscribe, $hub_callback, $hub_topic, $hub_secret);
 127
 128                 System::httpExit(202);
 129         }
 130         killme();
 131 }