+ Logger::log('Publish feed to ' . $subscriber['callback_url'] . ' for ' . $subscriber['nickname'] . ' with priority ' . $priority, Logger::DEBUG);
+ Worker::add($priority, 'PubSubPublish', (int)$subscriber['id']);
+ }
+
+ DBA::close($subscribers);
+ }
+
+ /**
+ * Renew the feed subscription
+ *
+ * @param integer $uid User ID
+ * @param string $nick Priority for push workers
+ * @param integer $subscribe Subscribe (Unsubscribe = false)
+ * @param string $hub_callback Callback address
+ * @param string $hub_topic Feed topic
+ * @param string $hub_secret Subscription secret
+ * @throws \Exception
+ */
+ public static function renew($uid, $nick, $subscribe, $hub_callback, $hub_topic, $hub_secret)
+ {
+ // fetch the old subscription if it exists
+ $subscriber = DBA::selectFirst('push_subscriber', ['last_update', 'push'], ['callback_url' => $hub_callback]);
+
+ // delete old subscription if it exists
+ DBA::delete('push_subscriber', ['callback_url' => $hub_callback]);
+
+ if ($subscribe) {
+ // if we are just updating an old subscription, keep the
+ // old values for last_update but reset the push
+ if (DBA::isResult($subscriber)) {
+ $last_update = $subscriber['last_update'];
+ $push_flag = min($subscriber['push'], 1);
+ } else {
+ $last_update = DateTimeFormat::utcNow();
+ $push_flag = 0;
+ }
+
+ // subscribe means adding the row to the table
+ $fields = ['uid' => $uid, 'callback_url' => $hub_callback,
+ 'topic' => $hub_topic, 'nickname' => $nick, 'push' => $push_flag,
+ 'last_update' => $last_update, 'renewed' => DateTimeFormat::utcNow(),
+ 'secret' => $hub_secret];
+ DBA::insert('push_subscriber', $fields);
+
+ Logger::log("Successfully subscribed [$hub_callback] for $nick");
+ } else {
+ Logger::log("Successfully unsubscribed [$hub_callback] for $nick");
+ // we do nothing here, since the row was already deleted
+ }
+ }
+
+ /**
+ * Delay the push subscriber
+ *
+ * @param integer $id Subscriber ID
+ * @throws \Exception
+ */
+ public static function delay($id)
+ {
+ $subscriber = DBA::selectFirst('push_subscriber', ['push', 'callback_url', 'renewed', 'nickname'], ['id' => $id]);
+ if (!DBA::isResult($subscriber)) {
+ return;
+ }
+
+ $retrial = $subscriber['push'];
+
+ if ($retrial > 14) {
+ // End subscriptions if they weren't renewed for more than two months
+ $days = round((time() - strtotime($subscriber['renewed'])) / (60 * 60 * 24));
+
+ if ($days > 60) {
+ DBA::update('push_subscriber', ['push' => -1, 'next_try' => DBA::NULL_DATETIME], ['id' => $id]);
+ Logger::log('Delivery error: Subscription ' . $subscriber['callback_url'] . ' for ' . $subscriber['nickname'] . ' is marked as ended.', Logger::DEBUG);
+ } else {
+ DBA::update('push_subscriber', ['push' => 0, 'next_try' => DBA::NULL_DATETIME], ['id' => $id]);
+ Logger::log('Delivery error: Giving up ' . $subscriber['callback_url'] . ' for ' . $subscriber['nickname'] . ' for now.', Logger::DEBUG);
+ }
+ } else {
+ // Calculate the delay until the next trial
+ $delay = (($retrial + 3) ** 4) + (rand(1, 30) * ($retrial + 1));
+ $next = DateTimeFormat::utc('now + ' . $delay . ' seconds');
+
+ $retrial = $retrial + 1;
+
+ DBA::update('push_subscriber', ['push' => $retrial, 'next_try' => $next], ['id' => $id]);
+ Logger::log('Delivery error: Next try (' . $retrial . ') ' . $subscriber['callback_url'] . ' for ' . $subscriber['nickname'] . ' at ' . $next, Logger::DEBUG);
+ }
+ }
+
+ /**
+ * Reset the push subscriber
+ *
+ * @param integer $id Subscriber ID
+ * @param string $last_update Date of last transmitted item
+ * @throws \Exception
+ */
+ public static function reset($id, $last_update)
+ {
+ $subscriber = DBA::selectFirst('push_subscriber', ['callback_url', 'nickname'], ['id' => $id]);
+ if (!DBA::isResult($subscriber)) {
+ return;