New "relay" class / check of incoming popsts from DFRN and Diaspora

src/Protocol/Relay.php

@@ -0,0 +1,114 @@
+<?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\Protocol;
+
+use Friendica\Content\Text\BBCode;
+use Friendica\Core\Logger;
+use Friendica\DI;
+use Friendica\Model\Search;
+
+/**
+ * Base class for relay handling
+ */
+final class Relay
+{
+	/**
+	 * Check if a post is wanted
+	 *
+	 * @param array $tags
+	 * @param string $body
+	 * @param string $url
+	 * @return boolean "true" is the post is wanted by the system
+	 */
+	public static function isSolicitedPost(array $tags, string $body, string $url, string $network = '')
+	{
+		$config = DI::config();
+
+		$subscribe = $config->get('system', 'relay_subscribe', false);
+		if ($subscribe) {
+			$scope = $config->get('system', 'relay_scope', SR_SCOPE_ALL);
+		} else {
+			$scope = SR_SCOPE_NONE;
+		}
+
+		if ($scope == SR_SCOPE_NONE) {
+			Logger::info('Server does not accept relay posts - rejected', ['network' => $network, 'url' => $url]);
+			return false;
+		}
+
+		$systemTags = [];
+		$userTags = [];
+		$denyTags = [];
+
+		if ($scope == SR_SCOPE_TAGS) {
+			$server_tags = $config->get('system', 'relay_server_tags');
+			$tagitems = explode(',', mb_strtolower($server_tags));
+			foreach ($tagitems AS $tag) {
+				$systemTags[] = trim($tag, '# ');
+			}
+
+			if ($config->get('system', 'relay_user_tags')) {
+				$userTags = Search::getUserTags();
+			}
+		}
+
+		$tagList = array_unique(array_merge($systemTags, $userTags));
+
+		$deny_tags = $config->get('system', 'relay_deny_tags');
+		$tagitems = explode(',', mb_strtolower($deny_tags));
+		foreach ($tagitems AS $tag) {
+			$tag = trim($tag, '# ');
+			$denyTags[] = $tag;
+		}
+
+		if (!empty($tagList) || !empty($denyTags)) {
+			$content = mb_strtolower(BBCode::toPlaintext($body, false));
+
+			foreach ($tags as $tag) {
+				if (in_array($tag, $denyTags)) {
+					Logger::info('Unwanted hashtag found - rejected', ['hashtag' => $tag, 'network' => $network, 'url' => $url]);
+					return false;
+				}
+
+				if (in_array($tag, $tagList)) {
+					Logger::info('Subscribed hashtag found - accepted', ['hashtag' => $tag, 'network' => $network, 'url' => $url]);
+					return true;
+				}
+
+				// We check with "strpos" for performance issues. Only when this is true, the regular expression check is used
+				// RegExp is taken from here: https://medium.com/@shiba1014/regex-word-boundaries-with-unicode-207794f6e7ed
+				if ((strpos($content, $tag) !== false) && preg_match('/(?<=[\s,.:;"\']|^)' . preg_quote($tag, '/') . '(?=[\s,.:;"\']|$)/', $content)) {
+					Logger::info('Subscribed hashtag found in content - accepted', ['hashtag' => $tag, 'network' => $network, 'url' => $url]);
+					return true;
+				}
+			}
+		}
+
+		if ($scope == SR_SCOPE_ALL) {
+			Logger::info('Server accept all posts - accepted', ['network' => $network, 'url' => $url]);
+			return true;
+		}
+
+		Logger::info('No matching hashtags found - rejected', ['network' => $network, 'url' => $url]);
+		return false;
+	}
+}