friendica_2021-01/mod/pubsubhubbub.php

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<?php
use Friendica\App;
use Friendica\Core\Config;
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use Friendica\Database\DBM;
function post_var($name) {
return (x($_POST, $name)) ? notags(trim($_POST[$name])) : '';
}
function pubsubhubbub_init(App $a) {
// PuSH subscription must be considered "public" so just block it
// if public access isn't enabled.
if (Config::get('system', 'block_public')) {
http_status_exit(403);
}
// Subscription request from subscriber
// https://pubsubhubbub.googlecode.com/git/pubsubhubbub-core-0.4.html#anchor4
// Example from GNU Social:
// [hub_mode] => subscribe
// [hub_callback] => http://status.local/main/push/callback/1
// [hub_verify] => sync
// [hub_verify_token] => af11...
// [hub_secret] => af11...
// [hub_topic] => http://friendica.local/dfrn_poll/sazius
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
$hub_mode = post_var('hub_mode');
$hub_callback = post_var('hub_callback');
$hub_verify = post_var('hub_verify');
$hub_verify_token = post_var('hub_verify_token');
$hub_secret = post_var('hub_secret');
$hub_topic = post_var('hub_topic');
// check for valid hub_mode
if ($hub_mode === 'subscribe') {
$subscribe = 1;
} elseif ($hub_mode === 'unsubscribe') {
$subscribe = 0;
} else {
logger("pubsubhubbub: invalid hub_mode=$hub_mode, ignoring.");
http_status_exit(404);
}
logger("pubsubhubbub: $hub_mode request from " .
$_SERVER['REMOTE_ADDR']);
// get the nick name from the topic, a bit hacky but needed as a fallback
$nick = substr(strrchr($hub_topic, "/"), 1);
// Normally the url should now contain the nick name as last part of the url
if ($a->argc > 1) {
$nick = $a->argv[1];
}
if (!$nick) {
logger('pubsubhubbub: bad hub_topic=$hub_topic, ignoring.');
http_status_exit(404);
}
// fetch user from database given the nickname
$r = q("SELECT * FROM `user` WHERE `nickname` = '%s'" .
" AND `account_expired` = 0 AND `account_removed` = 0 LIMIT 1",
dbesc($nick));
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if (!DBM::is_result($r)) {
logger('pubsubhubbub: local account not found: ' . $nick);
http_status_exit(404);
}
$owner = $r[0];
// abort if user's wall is supposed to be private
if ($r[0]['hidewall']) {
logger('pubsubhubbub: local user ' . $nick .
'has chosen to hide wall, ignoring.');
http_status_exit(403);
}
// get corresponding row from contact table
$r = q("SELECT * FROM `contact` WHERE `uid` = %d AND NOT `blocked`".
" AND NOT `pending` AND `self` LIMIT 1",
intval($owner['uid']));
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if (!DBM::is_result($r)) {
logger('pubsubhubbub: contact not found.');
http_status_exit(404);
}
$contact = $r[0];
// sanity check that topic URLs are the same
if (!link_compare($hub_topic, $contact['poll'])) {
logger('pubsubhubbub: hub topic ' . $hub_topic . ' != ' .
$contact['poll']);
http_status_exit(404);
}
// do subscriber verification according to the PuSH protocol
$hub_challenge = random_string(40);
$params = 'hub.mode=' .
($subscribe == 1 ? 'subscribe' : 'unsubscribe') .
'&hub.topic=' . urlencode($hub_topic) .
'&hub.challenge=' . $hub_challenge .
'&hub.lease_seconds=604800' .
'&hub.verify_token=' . $hub_verify_token;
// lease time is hard coded to one week (in seconds)
// we don't actually enforce the lease time because GNU
// Social/StatusNet doesn't honour it (yet)
$body = fetch_url($hub_callback . "?" . $params);
$ret = $a->get_curl_code();
// give up if the HTTP return code wasn't a success (2xx)
if ($ret < 200 || $ret > 299) {
logger("pubsubhubbub: subscriber verification at $hub_callback ".
"returned $ret, ignoring.");
http_status_exit(404);
}
// check that the correct hub_challenge code was echoed back
if (trim($body) !== $hub_challenge) {
logger("pubsubhubbub: subscriber did not echo back ".
"hub.challenge, ignoring.");
logger("\"$hub_challenge\" != \"".trim($body)."\"");
http_status_exit(404);
}
// fetch the old subscription if it exists
$r = q("SELECT * FROM `push_subscriber` WHERE `callback_url` = '%s'",
dbesc($hub_callback));
// delete old subscription if it exists
q("DELETE FROM `push_subscriber` WHERE `callback_url` = '%s'",
dbesc($hub_callback));
if ($subscribe) {
$last_update = datetime_convert('UTC','UTC','now','Y-m-d H:i:s');
$push_flag = 0;
// if we are just updating an old subscription, keep the
// old values for push and last_update
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if (DBM::is_result($r)) {
$last_update = $r[0]['last_update'];
$push_flag = $r[0]['push'];
}
// subscribe means adding the row to the table
q("INSERT INTO `push_subscriber` (`uid`, `callback_url`, " .
"`topic`, `nickname`, `push`, `last_update`, `secret`) values " .
"(%d, '%s', '%s', '%s', %d, '%s', '%s')",
intval($owner['uid']),
dbesc($hub_callback),
dbesc($hub_topic),
dbesc($nick),
intval($push_flag),
dbesc($last_update),
dbesc($hub_secret));
logger("pubsubhubbub: successfully subscribed [$hub_callback].");
} else {
logger("pubsubhubbub: successfully unsubscribed [$hub_callback].");
// we do nothing here, since the row was already deleted
}
http_status_exit(202);
}
killme();
}