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($name) {
  13         return !empty($_POST[$name]) ? Strings::escapeTags(trim($_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 " . $_SERVER['REMOTE_ADDR']);
  52
  53                 if ($a->argc > 1) {
  54                         // Normally the url should now contain the nick name as last part of the url
  55                         $nick = $a->argv[1];
  56                 } else {
  57                         // Get the nick name from the topic as a fallback
  58                         $nick = $hub_topic;
  59                 }
  60                 // Extract nick name and strip any .atom extension
  61                 $nick = basename($nick, '.atom');
  62
  63                 if (!$nick) {
  64                         Logger::log('Bad hub_topic=$hub_topic, ignoring.');
  65                         System::httpExit(404);
  66                 }
  67
  68                 // fetch user from database given the nickname
  69                 $condition = ['nickname' => $nick, 'account_expired' => false, 'account_removed' => false];
  70                 $owner = DBA::selectFirst('user', ['uid', 'hidewall', 'nickname'], $condition);
  71                 if (!DBA::isResult($owner)) {
  72                         Logger::log('Local account not found: ' . $nick . ' - topic: ' . $hub_topic . ' - callback: ' . $hub_callback);
  73                         System::httpExit(404);
  74                 }
  75
  76                 // abort if user's wall is supposed to be private
  77                 if ($owner['hidewall']) {
  78                         Logger::log('Local user ' . $nick . 'has chosen to hide wall, ignoring.');
  79                         System::httpExit(403);
  80                 }
  81
  82                 // get corresponding row from contact table
  83                 $condition = ['uid' => $owner['uid'], 'blocked' => false,
  84                         'pending' => false, 'self' => true];
  85                 $contact = DBA::selectFirst('contact', ['poll'], $condition);
  86                 if (!DBA::isResult($contact)) {
  87                         Logger::log('Self contact for user ' . $owner['uid'] . ' not found.');
  88                         System::httpExit(404);
  89                 }
  90
  91                 // sanity check that topic URLs are the same
  92                 $hub_topic2 = str_replace('/feed/', '/dfrn_poll/', $hub_topic);
  93                 $self = System::baseUrl() . '/api/statuses/user_timeline/' . $owner['nickname'] . '.atom';
  94
  95                 if (!Strings::compareLink($hub_topic, $contact['poll']) && !Strings::compareLink($hub_topic2, $contact['poll']) && !Strings::compareLink($hub_topic, $self)) {
  96                         Logger::log('Hub topic ' . $hub_topic . ' != ' . $contact['poll']);
  97                         System::httpExit(404);
  98                 }
  99
 100                 // do subscriber verification according to the PuSH protocol
 101                 $hub_challenge = Strings::getRandomHex(40);
 102
 103                 $params = http_build_query([
 104                         'hub.mode' => $subscribe == 1 ? 'subscribe' : 'unsubscribe',
 105                         'hub.topic' => $hub_topic,
 106                         'hub.challenge' => $hub_challenge,
 107                         'hub.verify_token' => $hub_verify_token,
 108
 109                         // lease time is hard coded to one week (in seconds)
 110                         // we don't actually enforce the lease time because GNU
 111                         // Social/StatusNet doesn't honour it (yet)
 112                         'hub.lease_seconds' => 604800,
 113                 ]);
 114
 115                 $hub_callback = rtrim($hub_callback, ' ?&#');
 116                 $separator = parse_url($hub_callback, PHP_URL_QUERY) === null ? '?' : '&';
 117
 118                 $fetchResult = Network::fetchUrlFull($hub_callback . $separator . $params);
 119                 $body = $fetchResult->getBody();
 120                 $ret = $fetchResult->getReturnCode();
 121
 122                 // give up if the HTTP return code wasn't a success (2xx)
 123                 if ($ret < 200 || $ret > 299) {
 124                         Logger::log("Subscriber verification for $hub_topic at $hub_callback returned $ret, ignoring.");
 125                         System::httpExit(404);
 126                 }
 127
 128                 // check that the correct hub_challenge code was echoed back
 129                 if (trim($body) !== $hub_challenge) {
 130                         Logger::log("Subscriber did not echo back hub.challenge, ignoring.");
 131                         Logger::log("\"$hub_challenge\" != \"".trim($body)."\"");
 132                         System::httpExit(404);
 133                 }
 134
 135                 PushSubscriber::renew($owner['uid'], $nick, $subscribe, $hub_callback, $hub_topic, $hub_secret);
 136
 137                 System::httpExit(202);
 138         }
 139         killme();
 140 }