Discovery of peers of other servers

src/Model/GServer.php

@@ -1591,9 +1591,9 @@ class GServer
 		$gservers = DBA::p("SELECT `id`, `url`, `nurl`, `network`, `poco`
 			FROM `gserver`
 			WHERE NOT `failed`
-			AND `poco` != ''
+			AND `directory-type` != ?
 			AND `last_poco_query` < ?
-			ORDER BY RAND()", $last_update
+			ORDER BY RAND()", self::DT_NONE, $last_update
 		);
 
 		while ($gserver = DBA::fetch($gservers)) {
@@ -1604,8 +1604,13 @@ class GServer
 				continue;
 			}
 
+			Logger::info('Update peer list', ['server' => $gserver['url'], 'id' => $gserver['id']]);
+			Worker::add(PRIORITY_LOW, 'UpdateServerPeers', $gserver['url']);
+
+			if ($gserver['directory-type'] == self::DT_POCO) {
 				Logger::info('Update directory', ['server' => $gserver['url'], 'id' => $gserver['id']]);
 				Worker::add(PRIORITY_LOW, 'UpdateServerDirectory', $gserver);
+			}
 
 			if (--$no_of_queries == 0) {
 				break;

src/Worker/UpdateServerPeers.php

@@ -0,0 +1,66 @@
+<?php
+/**
+ * @copyright Copyright (C) 2020, Friendica
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Friendica\Worker;
+
+use Friendica\Core\Logger;
+use Friendica\Core\Worker;
+use Friendica\Database\DBA;
+use Friendica\DI;
+use Friendica\Util\Strings;
+
+class UpdateServerPeers
+{
+	/**
+	 * Query the given server for their known peers
+	 * @param string $gserver Server URL
+	 */
+	public static function execute(string $url)
+	{
+		$ret = DI::httpRequest()->get($url . '/api/v1/instance/peers');
+		if (!$ret->isSuccess() || empty($ret->getBody())) {
+			Logger::info('Server is not reachable or does not offer the "peers" endpoint', ['url' => $url]);
+			return;
+		}
+
+		$peers = json_decode($ret->getBody());
+		if (empty($peers) || !is_array($peers)) {
+			Logger::info('Server does not have any peers listed', ['url' => $url]);
+			return;
+		}
+
+		Logger::info('Server peer update start', ['url' => $url]);
+
+		$total = 0;
+		$added = 0;
+		foreach ($peers as $peer) {
+			++$total;
+			if (DBA::exists('gserver', ['nurl' => Strings::normaliseLink('http://' . $peer)])) {
+				// We already know this server
+				continue;
+			}
+			// This endpoint doesn't offer the schema. So we assume that it is HTTPS.
+			Worker::add(PRIORITY_LOW, 'UpdateGServer', 'https://' . $peer);
+			++$added;
+		}
+		Logger::info('Server peer update ended', ['total' => $total, 'added' => $added, 'url' => $url]);
+	}
+}