codysnider / tt-rss

classes/rssutils.php

<?php
class RSSUtils {
    public static function calculate_article_hash($article, $pluginhost) {
        $tmp = "";

        foreach ($article as $k => $v) {
            if ($k != "feed" && isset($v)) {
                $x = strip_tags(is_array($v) ? implode(",", $v) : $v);

                $tmp .= sha1("$k:".sha1($x));
            }
        }

        return sha1(implode(",", $pluginhost->get_plugin_names()).$tmp);
    }

    // Strips utf8mb4 characters (i.e. emoji) for mysql
    public static function strip_utf8mb4($str) {
        return preg_replace('/[\x{10000}-\x{10FFFF}]/u', "\xEF\xBF\xBD", $str);
    }

    public static function cleanup_feed_browser() {
        $pdo = Db::pdo();
        $pdo->query("DELETE FROM ttrss_feedbrowser_cache");
    }

    public static function update_daemon_common($limit = DAEMON_FEED_LIMIT) {
        $schema_version = get_schema_version();

        if ($schema_version != SCHEMA_VERSION) {
            die("Schema version is wrong, please upgrade the database.\n");
        }

        $pdo = Db::pdo();

        if (!SINGLE_USER_MODE && DAEMON_UPDATE_LOGIN_LIMIT > 0) {
            if (DB_TYPE == "pgsql") {
                $login_thresh_qpart = "AND ttrss_users.last_login >= NOW() - INTERVAL '".DAEMON_UPDATE_LOGIN_LIMIT." days'";
            } else {
                $login_thresh_qpart = "AND ttrss_users.last_login >= DATE_SUB(NOW(), INTERVAL ".DAEMON_UPDATE_LOGIN_LIMIT." DAY)";
            }
        } else {
            $login_thresh_qpart = "";
        }

        if (DB_TYPE == "pgsql") {
            $update_limit_qpart = "AND ((
					ttrss_feeds.update_interval = 0
					AND ttrss_user_prefs.value != '-1'
					AND ttrss_feeds.last_updated < NOW() - CAST((ttrss_user_prefs.value || ' minutes') AS INTERVAL)
				) OR (
					ttrss_feeds.update_interval > 0
					AND ttrss_feeds.last_updated < NOW() - CAST((ttrss_feeds.update_interval || ' minutes') AS INTERVAL)
				) OR (ttrss_feeds.last_updated IS NULL
					AND ttrss_user_prefs.value != '-1')
				OR (last_updated = '1970-01-01 00:00:00'
					AND ttrss_user_prefs.value != '-1'))";
        } else {
            $update_limit_qpart = "AND ((
					ttrss_feeds.update_interval = 0
					AND ttrss_user_prefs.value != '-1'
					AND ttrss_feeds.last_updated < DATE_SUB(NOW(), INTERVAL CONVERT(ttrss_user_prefs.value, SIGNED INTEGER) MINUTE)
				) OR (
					ttrss_feeds.update_interval > 0
					AND ttrss_feeds.last_updated < DATE_SUB(NOW(), INTERVAL ttrss_feeds.update_interval MINUTE)
				) OR (ttrss_feeds.last_updated IS NULL
					AND ttrss_user_prefs.value != '-1')
				OR (last_updated = '1970-01-01 00:00:00'
					AND ttrss_user_prefs.value != '-1'))";
        }

        // Test if feed is currently being updated by another process.
        if (DB_TYPE == "pgsql") {
            $updstart_thresh_qpart = "AND (ttrss_feeds.last_update_started IS NULL OR ttrss_feeds.last_update_started < NOW() - INTERVAL '10 minutes')";
        } else {
            $updstart_thresh_qpart = "AND (ttrss_feeds.last_update_started IS NULL OR ttrss_feeds.last_update_started < DATE_SUB(NOW(), INTERVAL 10 MINUTE))";
        }

        $query_limit = $limit ? sprintf("LIMIT %d", $limit) : "";

        // Update the least recently updated feeds first
        $query_order = "ORDER BY last_updated";
        if (DB_TYPE == "pgsql") {
            $query_order .= " NULLS FIRST";
        }

        $query = "SELECT DISTINCT ttrss_feeds.feed_url, ttrss_feeds.last_updated
			FROM
				ttrss_feeds, ttrss_users, ttrss_user_prefs
			WHERE
				ttrss_feeds.owner_uid = ttrss_users.id
				AND ttrss_user_prefs.profile IS NULL
				AND ttrss_users.id = ttrss_user_prefs.owner_uid
				AND ttrss_user_prefs.pref_name = 'DEFAULT_UPDATE_INTERVAL'
				$login_thresh_qpart $update_limit_qpart
				$updstart_thresh_qpart
				$query_order $query_limit";

        $res = $pdo->query($query);

        $feeds_to_update = array();
        while ($line = $res->fetch()) {
            array_push($feeds_to_update, $line['feed_url']);
        }

        Debug::log(sprintf("Scheduled %d feeds to update...", count($feeds_to_update)));

        // Update last_update_started before actually starting the batch
        // in order to minimize collision risk for parallel daemon tasks
        if (count($feeds_to_update) > 0) {
            $feeds_qmarks = arr_qmarks($feeds_to_update);

            $tmph = $pdo->prepare("UPDATE ttrss_feeds SET last_update_started = NOW()
				WHERE feed_url IN ($feeds_qmarks)");
            $tmph->execute($feeds_to_update);
        }

        $nf = 0;
        $bstarted = microtime(true);

        $batch_owners = array();

        // since we have the data cached, we can deal with other feeds with the same url
        $usth = $pdo->prepare("SELECT DISTINCT ttrss_feeds.id,last_updated,ttrss_feeds.owner_uid
			FROM ttrss_feeds, ttrss_users, ttrss_user_prefs WHERE
				ttrss_user_prefs.owner_uid = ttrss_feeds.owner_uid AND
				ttrss_users.id = ttrss_user_prefs.owner_uid AND
				ttrss_user_prefs.pref_name = 'DEFAULT_UPDATE_INTERVAL' AND
				ttrss_user_prefs.profile IS NULL AND
				feed_url = ?
				$update_limit_qpart
				$login_thresh_qpart
			ORDER BY ttrss_feeds.id $query_limit");

        foreach ($feeds_to_update as $feed) {
            Debug::log("Base feed: $feed");

            $usth->execute([$feed]);
            //update_rss_feed($line["id"], true);

            if ($tline = $usth->fetch()) {
                Debug::log(" => ".$tline["last_updated"].", ".$tline["id"]." ".$tline["owner_uid"]);

                if (array_search($tline["owner_uid"], $batch_owners) === false) {
                                    array_push($batch_owners, $tline["owner_uid"]);
                }

                $fstarted = microtime(true);

                try {
                    RSSUtils::update_rss_feed($tline["id"], true, false);
                } catch (PDOException $e) {
                    Logger::get()->log_error(E_USER_NOTICE, $e->getMessage(), $e->getFile(), $e->getLine(), $e->getTraceAsString());

                    try {
                        $pdo->rollback();
                    } catch (PDOException $e) {
                        // it doesn't matter if there wasn't actually anything to rollback, PDO Exception can be
                        // thrown outside of an active transaction during feed update
                    }
                }

                Debug::log(sprintf("    %.4f (sec)", microtime(true) - $fstarted));

                ++$nf;
            }
        }

        if ($nf > 0) {
            Debug::log(sprintf("Processed %d feeds in %.4f (sec), %.4f (sec/feed avg)", $nf,
                microtime(true) - $bstarted, (microtime(true) - $bstarted) / $nf));
        }

        foreach ($batch_owners as $owner_uid) {
            Debug::log("Running housekeeping tasks for user $owner_uid...");

            RSSUtils::housekeeping_user($owner_uid);
        }

        // Send feed digests by email if needed.
        Digest::send_headlines_digests();

        return $nf;
    }

    // this is used when subscribing
    public static function set_basic_feed_info($feed) {

        $pdo = Db::pdo();

        $sth = $pdo->prepare("SELECT owner_uid,feed_url,auth_pass,auth_login
				FROM ttrss_feeds WHERE id = ?");
        $sth->execute([$feed]);

        if ($row = $sth->fetch()) {

            $owner_uid = $row["owner_uid"];
            $auth_login = $row["auth_login"];
            $auth_pass = $row["auth_pass"];
            $fetch_url = $row["feed_url"];

            $pluginhost = new PluginHost();
            $user_plugins = get_pref("_ENABLED_PLUGINS", $owner_uid);

            $pluginhost->load(PLUGINS, PluginHost::KIND_ALL);
            $pluginhost->load($user_plugins, PluginHost::KIND_USER, $owner_uid);
            $pluginhost->load_data();

            $basic_info = array();
            foreach ($pluginhost->get_hooks(PluginHost::HOOK_FEED_BASIC_INFO) as $plugin) {
                $basic_info = $plugin->hook_feed_basic_info($basic_info, $fetch_url, $owner_uid, $feed, $auth_login, $auth_pass);
            }

            if (!$basic_info) {
                $feed_data = fetch_file_contents($fetch_url, false,
                    $auth_login, $auth_pass, false,
                    FEED_FETCH_TIMEOUT,
                    0);

                $feed_data = trim($feed_data);

                $rss = new FeedParser($feed_data);
                $rss->init();

                if (!$rss->error()) {
                    $basic_info = array(
                        'title' => mb_substr(clean($rss->get_title()), 0, 199),
                        'site_url' => mb_substr(rewrite_relative_url($fetch_url, clean($rss->get_link())), 0, 245)
                    );
                }
            }

            if ($basic_info && is_array($basic_info)) {
                $sth = $pdo->prepare("SELECT title, site_url FROM ttrss_feeds WHERE id = ?");
                $sth->execute([$feed]);

                if ($row = $sth->fetch()) {

                    $registered_title = $row["title"];
                    $orig_site_url = $row["site_url"];

                    if ($basic_info['title'] && (!$registered_title || $registered_title == "[Unknown]")) {

                        $sth = $pdo->prepare("UPDATE ttrss_feeds SET
							title = ? WHERE id = ?");
                        $sth->execute([$basic_info['title'], $feed]);
                    }

                    if ($basic_info['site_url'] && $orig_site_url != $basic_info['site_url']) {
                        $sth = $pdo->prepare("UPDATE ttrss_feeds SET
							site_url = ? WHERE id = ?");
                        $sth->execute([$basic_info['site_url'], $feed]);
                    }

                }
            }
        }
    }

    /**
     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
     */
    public static function update_rss_feed($feed, $no_cache = false) {

        reset_fetch_domain_quota();

        Debug::log("start", Debug::$LOG_VERBOSE);

        $pdo = Db::pdo();

        $sth = $pdo->prepare("SELECT title, site_url FROM ttrss_feeds WHERE id = ?");
        $sth->execute([$feed]);

        if (!$row = $sth->fetch()) {
            Debug::log("feed $feed not found, skipping.");
            user_error("Attempt to update unknown/invalid feed $feed", E_USER_WARNING);
            return false;
        }

        $title = $row["title"];
        $site_url = $row["site_url"];

        // feed was batch-subscribed or something, we need to get basic info
        // this is not optimal currently as it fetches stuff separately TODO: optimize
        if ($title == "[Unknown]" || !$title || !$site_url) {
            Debug::log("setting basic feed info for $feed [$title, $site_url]...");
            RSSUtils::set_basic_feed_info($feed);
        }

        $sth = $pdo->prepare("SELECT id,update_interval,auth_login,
			feed_url,auth_pass,cache_images,
			mark_unread_on_update, owner_uid,
			auth_pass_encrypted, feed_language,
			last_modified,
			".SUBSTRING_FOR_DATE."(last_unconditional, 1, 19) AS last_unconditional
			FROM ttrss_feeds WHERE id = ?");
        $sth->execute([$feed]);

        if ($row = $sth->fetch()) {

            $owner_uid = $row["owner_uid"];
            $mark_unread_on_update = $row["mark_unread_on_update"];

            $sth = $pdo->prepare("UPDATE ttrss_feeds SET last_update_started = NOW()
				WHERE id = ?");
            $sth->execute([$feed]);

            $auth_login = $row["auth_login"];
            $auth_pass = $row["auth_pass"];
            $stored_last_modified = $row["last_modified"];
            $last_unconditional = $row["last_unconditional"];
            $cache_images = $row["cache_images"];
            $fetch_url = $row["feed_url"];

            $feed_language = mb_strtolower($row["feed_language"]);

            if (!$feed_language) {
                            $feed_language = mb_strtolower(get_pref('DEFAULT_SEARCH_LANGUAGE', $owner_uid));
            }

            if (!$feed_language) {
                            $feed_language = 'simple';
            }

        } else {
            return false;
        }

        $date_feed_processed = date('Y-m-d H:i');

        $cache_filename = CACHE_DIR."/feeds/".sha1($fetch_url).".xml";

        $pluginhost = new PluginHost();
        $user_plugins = get_pref("_ENABLED_PLUGINS", $owner_uid);

        $pluginhost->load(PLUGINS, PluginHost::KIND_ALL);
        $pluginhost->load($user_plugins, PluginHost::KIND_USER, $owner_uid);
        $pluginhost->load_data();

        $rss_hash = false;

        $force_refetch = isset($_REQUEST["force_refetch"]);
        $feed_data = "";

        Debug::log("running HOOK_FETCH_FEED handlers...", Debug::$LOG_VERBOSE);

        foreach ($pluginhost->get_hooks(PluginHost::HOOK_FETCH_FEED) as $plugin) {
            Debug::log("... ".get_class($plugin), Debug::$LOG_VERBOSE);
            $start = microtime(true);
            $feed_data = $plugin->hook_fetch_feed($feed_data, $fetch_url, $owner_uid, $feed, 0, $auth_login, $auth_pass);
            Debug::log(sprintf("=== %.4f (sec)", microtime(true) - $start), Debug::$LOG_VERBOSE);
        }

        if ($feed_data) {
            Debug::log("feed data has been modified by a plugin.", Debug::$LOG_VERBOSE);
        } else {
            Debug::log("feed data has not been modified by a plugin.", Debug::$LOG_VERBOSE);
        }

        // try cache
        if (!$feed_data &&
            file_exists($cache_filename) &&
            is_readable($cache_filename) &&
            !$auth_login && !$auth_pass &&
            filemtime($cache_filename) > time() - 30) {

            Debug::log("using local cache [$cache_filename].", Debug::$LOG_VERBOSE);

            @$feed_data = file_get_contents($cache_filename);

            if ($feed_data) {
                $rss_hash = sha1($feed_data);
            }

        } else {
            Debug::log("local cache will not be used for this feed", Debug::$LOG_VERBOSE);
        }

        global $fetch_last_modified;

        // fetch feed from source
        if (!$feed_data) {
            Debug::log("last unconditional update request: $last_unconditional", Debug::$LOG_VERBOSE);

            if (ini_get("open_basedir") && function_exists("curl_init")) {
                Debug::log("not using CURL due to open_basedir restrictions", Debug::$LOG_VERBOSE);
            }

            if (time() - strtotime($last_unconditional) > MAX_CONDITIONAL_INTERVAL) {
                Debug::log("maximum allowed interval for conditional requests exceeded, forcing refetch", Debug::$LOG_VERBOSE);

                $force_refetch = true;
            } else {
                Debug::log("stored last modified for conditional request: $stored_last_modified", Debug::$LOG_VERBOSE);
            }

            Debug::log("fetching [$fetch_url] (force_refetch: $force_refetch)...", Debug::$LOG_VERBOSE);

            $feed_data = fetch_file_contents([
                "url" => $fetch_url,
                "login" => $auth_login,
                "pass" => $auth_pass,
                "timeout" => $no_cache ? FEED_FETCH_NO_CACHE_TIMEOUT : FEED_FETCH_TIMEOUT,
                "last_modified" => $force_refetch ? "" : $stored_last_modified
            ]);

            $feed_data = trim($feed_data);

            Debug::log("fetch done.", Debug::$LOG_VERBOSE);
            Debug::log("source last modified: ".$fetch_last_modified, Debug::$LOG_VERBOSE);

            if ($feed_data && $fetch_last_modified != $stored_last_modified) {
                $sth = $pdo->prepare("UPDATE ttrss_feeds SET last_modified = ? WHERE id = ?");
                $sth->execute([substr($fetch_last_modified, 0, 245), $feed]);
            }

            // cache vanilla feed data for re-use
            if ($feed_data && !$auth_pass && !$auth_login && is_writable(CACHE_DIR."/feeds")) {
                $new_rss_hash = sha1($feed_data);

                if ($new_rss_hash != $rss_hash) {
                    Debug::log("saving $cache_filename", Debug::$LOG_VERBOSE);
                    @file_put_contents($cache_filename, $feed_data);

It seems like you do not handle an error condition for file_put_contents(). This can introduce security issues, and is generally not recommended.

                }
            }
        }

        if (!$feed_data) {
            global $fetch_last_error;
            global $fetch_last_error_code;

            Debug::log("unable to fetch: $fetch_last_error [$fetch_last_error_code]", Debug::$LOG_VERBOSE);

            // If-Modified-Since
            if ($fetch_last_error_code != 304) {
                $error_message = $fetch_last_error;
            } else {
                Debug::log("source claims data not modified, nothing to do.", Debug::$LOG_VERBOSE);
                $error_message = "";
            }

            $sth = $pdo->prepare("UPDATE ttrss_feeds SET last_error = ?,
					last_updated = NOW() WHERE id = ?");
            $sth->execute([$error_message, $feed]);

            return;
        }

        Debug::log("running HOOK_FEED_FETCHED handlers...", Debug::$LOG_VERBOSE);
        $feed_data_checksum = md5($feed_data);

        foreach ($pluginhost->get_hooks(PluginHost::HOOK_FEED_FETCHED) as $plugin) {
            Debug::log("... ".get_class($plugin), Debug::$LOG_VERBOSE);
            $start = microtime(true);
            $feed_data = $plugin->hook_feed_fetched($feed_data, $fetch_url, $owner_uid, $feed);
            Debug::log(sprintf("=== %.4f (sec)", microtime(true) - $start), Debug::$LOG_VERBOSE);
        }

        if (md5($feed_data) != $feed_data_checksum) {
            Debug::log("feed data has been modified by a plugin.", Debug::$LOG_VERBOSE);
        } else {
            Debug::log("feed data has not been modified by a plugin.", Debug::$LOG_VERBOSE);
        }

        $rss = new FeedParser($feed_data);
        $rss->init();

        if (!$rss->error()) {

            Debug::log("running HOOK_FEED_PARSED handlers...", Debug::$LOG_VERBOSE);

            // We use local pluginhost here because we need to load different per-user feed plugins

            foreach ($pluginhost->get_hooks(PluginHost::HOOK_FEED_PARSED) as $plugin) {
                Debug::log("... ".get_class($plugin), Debug::$LOG_VERBOSE);
                $start = microtime(true);
                $plugin->hook_feed_parsed($rss);
                Debug::log(sprintf("=== %.4f (sec)", microtime(true) - $start), Debug::$LOG_VERBOSE);
            }

            Debug::log("language: $feed_language", Debug::$LOG_VERBOSE);
            Debug::log("processing feed data...", Debug::$LOG_VERBOSE);

            if (DB_TYPE == "pgsql") {
                $favicon_interval_qpart = "favicon_last_checked < NOW() - INTERVAL '12 hour'";
            } else {
                $favicon_interval_qpart = "favicon_last_checked < DATE_SUB(NOW(), INTERVAL 12 HOUR)";
            }

            $sth = $pdo->prepare("SELECT owner_uid,favicon_avg_color,
				(favicon_last_checked IS NULL OR $favicon_interval_qpart) AS
						favicon_needs_check
				FROM ttrss_feeds WHERE id = ?");
            $sth->execute([$feed]);

            if ($row = $sth->fetch()) {
                $favicon_needs_check = $row["favicon_needs_check"];
                $favicon_avg_color = $row["favicon_avg_color"];
                $owner_uid = $row["owner_uid"];
            } else {
                return false;
            }

            $site_url = mb_substr(rewrite_relative_url($fetch_url, clean($rss->get_link())), 0, 245);

            Debug::log("site_url: $site_url", Debug::$LOG_VERBOSE);
            Debug::log("feed_title: ".clean($rss->get_title()), Debug::$LOG_VERBOSE);

            if ($favicon_needs_check || $force_refetch) {

                /* terrible hack: if we crash on floicon shit here, we won't check
				 * the icon avgcolor again (unless the icon got updated) */

                $favicon_file = ICONS_DIR."/$feed.ico";
                $favicon_modified = @filemtime($favicon_file);

                Debug::log("checking favicon...", Debug::$LOG_VERBOSE);

                RSSUtils::check_feed_favicon($site_url, $feed);
                $favicon_modified_new = @filemtime($favicon_file);

                if ($favicon_modified_new > $favicon_modified) {
                                    $favicon_avg_color = '';
                }

                $favicon_colorstring = "";
                if (file_exists($favicon_file) && function_exists("imagecreatefromstring") && $favicon_avg_color == '') {
                    require_once "colors.php";

                    $sth = $pdo->prepare("UPDATE ttrss_feeds SET favicon_avg_color = 'fail' WHERE
							id = ?");
                    $sth->execute([$feed]);

                    $favicon_color = calculate_avg_color($favicon_file);

                    $favicon_colorstring = ",favicon_avg_color = ".$pdo->quote($favicon_color);

                } else if ($favicon_avg_color == 'fail') {
                    Debug::log("floicon failed on this file, not trying to recalculate avg color", Debug::$LOG_VERBOSE);
                }

                $sth = $pdo->prepare("UPDATE ttrss_feeds SET favicon_last_checked = NOW()
					$favicon_colorstring WHERE id = ?");
                $sth->execute([$feed]);
            }

            Debug::log("loading filters & labels...", Debug::$LOG_VERBOSE);

            $filters = RSSUtils::load_filters($feed, $owner_uid);

            if (Debug::get_loglevel() >= Debug::$LOG_EXTENDED) {
                print_r($filters);
            }

            Debug::log("".count($filters)." filters loaded.", Debug::$LOG_VERBOSE);

            $items = $rss->get_items();

            if (!is_array($items)) {
                Debug::log("no articles found.", Debug::$LOG_VERBOSE);

                $sth = $pdo->prepare("UPDATE ttrss_feeds
					SET last_updated = NOW(), last_unconditional = NOW(), last_error = '' WHERE id = ?");
                $sth->execute([$feed]);

                return true; // no articles
            }

            Debug::log("processing articles...", Debug::$LOG_VERBOSE);

            $tstart = time();

            foreach ($items as $item) {
                $pdo->beginTransaction();

                if (Debug::get_loglevel() >= 3) {
                    print_r($item);
                }

                if (ini_get("max_execution_time") > 0 && time() - $tstart >= ini_get("max_execution_time") * 0.7) {
                    Debug::log("looks like there's too many articles to process at once, breaking out", Debug::$LOG_VERBOSE);
                    $pdo->commit();
                    break;
                }

                $entry_guid = strip_tags($item->get_id());
                if (!$entry_guid) {
                    $entry_guid = strip_tags($item->get_link());
                }
                if (!$entry_guid) {
                    $entry_guid = RSSUtils::make_guid_from_title($item->get_title());
                }

                if (!$entry_guid) {
                    $pdo->commit();
                    continue;
                }

                $entry_guid = "$owner_uid,$entry_guid";

                $entry_guid_hashed = 'SHA1:'.sha1($entry_guid);

                Debug::log("guid $entry_guid / $entry_guid_hashed", Debug::$LOG_VERBOSE);

                $entry_timestamp = (int) $item->get_date();

                Debug::log("orig date: ".$item->get_date(), Debug::$LOG_VERBOSE);

                $entry_title = strip_tags($item->get_title());

                $entry_link = rewrite_relative_url($site_url, clean($item->get_link()));

                $entry_language = mb_substr(trim($item->get_language()), 0, 2);

                Debug::log("title $entry_title", Debug::$LOG_VERBOSE);
                Debug::log("link $entry_link", Debug::$LOG_VERBOSE);
                Debug::log("language $entry_language", Debug::$LOG_VERBOSE);

                if (!$entry_title) {
                    $entry_title = date("Y-m-d H:i:s", $entry_timestamp);
                }
                ;

                $entry_content = $item->get_content();
                if (!$entry_content) {
                    $entry_content = $item->get_description();
                }

                if (Debug::get_loglevel() >= 3) {
                    print "content: ";
                    print htmlspecialchars($entry_content);
                    print "\n";
                }

                $entry_comments = mb_substr(strip_tags($item->get_comments_url()), 0, 245);
                $num_comments = (int) $item->get_comments_count();

                $entry_author = strip_tags($item->get_author());
                $entry_guid = mb_substr($entry_guid, 0, 245);

                Debug::log("author $entry_author", Debug::$LOG_VERBOSE);
                Debug::log("looking for tags...", Debug::$LOG_VERBOSE);

                $entry_tags = $item->get_categories();
                Debug::log("tags found: ".join(", ", $entry_tags), Debug::$LOG_VERBOSE);

                Debug::log("done collecting data.", Debug::$LOG_VERBOSE);

                $sth = $pdo->prepare("SELECT id, content_hash, lang FROM ttrss_entries
					WHERE guid = ? OR guid = ?");
                $sth->execute([$entry_guid, $entry_guid_hashed]);

                if ($row = $sth->fetch()) {
                    $base_entry_id = $row["id"];
                    $entry_stored_hash = $row["content_hash"];
                    $article_labels = Article::get_article_labels($base_entry_id, $owner_uid);

                    $existing_tags = Article::get_article_tags($base_entry_id, $owner_uid);
                    $entry_tags = array_unique(array_merge($entry_tags, $existing_tags));
                } else {
                    $base_entry_id = false;
                    $entry_stored_hash = "";
                    $article_labels = array();
                }

                $article = array("owner_uid" => $owner_uid, // read only
                    "guid" => $entry_guid, // read only
                    "guid_hashed" => $entry_guid_hashed, // read only
                    "title" => $entry_title,
                    "content" => $entry_content,
                    "link" => $entry_link,
                    "labels" => $article_labels, // current limitation: can add labels to article, can't remove them
                    "tags" => $entry_tags,
                    "author" => $entry_author,
                    "force_catchup" => false, // ugly hack for the time being
                    "score_modifier" => 0, // no previous value, plugin should recalculate score modifier based on content if needed
                    "language" => $entry_language,
                    "timestamp" => $entry_timestamp,
                    "num_comments" => $num_comments,
                    "feed" => array("id" => $feed,
                        "fetch_url" => $fetch_url,
                        "site_url" => $site_url,
                        "cache_images" => $cache_images)
                );

                $entry_plugin_data = "";
                $entry_current_hash = RSSUtils::calculate_article_hash($article, $pluginhost);

                Debug::log("article hash: $entry_current_hash [stored=$entry_stored_hash]", Debug::$LOG_VERBOSE);

                if ($entry_current_hash == $entry_stored_hash && !isset($_REQUEST["force_rehash"])) {
                    Debug::log("stored article seems up to date [IID: $base_entry_id], updating timestamp only", Debug::$LOG_VERBOSE);

                    // we keep encountering the entry in feeds, so we need to
                    // update date_updated column so that we don't get horrible
                    // dupes when the entry gets purged and reinserted again e.g.
                    // in the case of SLOW SLOW OMG SLOW updating feeds

                    $sth = $pdo->prepare("UPDATE ttrss_entries SET date_updated = NOW()
						WHERE id = ?");
                    $sth->execute([$base_entry_id]);

                    $pdo->commit();
                    continue;
                }

                Debug::log("hash differs, applying plugin filters:", Debug::$LOG_VERBOSE);

                foreach ($pluginhost->get_hooks(PluginHost::HOOK_ARTICLE_FILTER) as $plugin) {
                    Debug::log("... ".get_class($plugin), Debug::$LOG_VERBOSE);

                    $start = microtime(true);
                    $article = $plugin->hook_article_filter($article);

                    Debug::log(sprintf("=== %.4f (sec)", microtime(true) - $start), Debug::$LOG_VERBOSE);

                    $entry_plugin_data .= mb_strtolower(get_class($plugin)).",";
                }

                if (Debug::get_loglevel() >= 3) {
                    print "processed content: ";
                    print htmlspecialchars($article["content"]);
                    print "\n";
                }

                Debug::log("plugin data: $entry_plugin_data", Debug::$LOG_VERBOSE);

                // Workaround: 4-byte unicode requires utf8mb4 in MySQL. See https://tt-rss.org/forum/viewtopic.php?f=1&t=3377&p=20077#p20077
                if (DB_TYPE == "mysql" && MYSQL_CHARSET != "UTF8MB4") {
                    foreach ($article as $k => $v) {
                        // i guess we'll have to take the risk of 4byte unicode labels & tags here
                        if (is_string($article[$k])) {
                            $article[$k] = RSSUtils::strip_utf8mb4($v);
                        }
                    }
                }

                /* Collect article tags here so we could filter by them: */

                $matched_rules = [];
                $matched_filters = [];

                $article_filters = RSSUtils::get_article_filters($filters, $article["title"],
                    $article["content"], $article["link"], $article["author"],
                    $article["tags"], $matched_rules, $matched_filters);

                // $article_filters should be renamed to something like $filter_actions; actual filter objects are in $matched_filters
                foreach ($pluginhost->get_hooks(PluginHost::HOOK_FILTER_TRIGGERED) as $plugin) {
                    $plugin->hook_filter_triggered($feed, $owner_uid, $article, $matched_filters, $matched_rules, $article_filters);
                }

                $matched_filter_ids = array_map(function($f) { return $f['id']; }, $matched_filters);

                if (count($matched_filter_ids) > 0) {
                    $filter_ids_qmarks = arr_qmarks($matched_filter_ids);

                    $fsth = $pdo->prepare("UPDATE ttrss_filters2 SET last_triggered = NOW() WHERE
							   id IN ($filter_ids_qmarks) AND owner_uid = ?");

                    $fsth->execute(array_merge($matched_filter_ids, [$owner_uid]));
                }

                if (Debug::get_loglevel() >= Debug::$LOG_EXTENDED) {
                    Debug::log("matched filters: ", Debug::$LOG_VERBOSE);

                    if (count($matched_filters != 0)) {
                        print_r($matched_filters);
                    }

                    Debug::log("matched filter rules: ", Debug::$LOG_VERBOSE);

                    if (count($matched_rules) != 0) {
                        print_r($matched_rules);
                    }

                    Debug::log("filter actions: ", Debug::$LOG_VERBOSE);

                    if (count($article_filters) != 0) {
                        print_r($article_filters);
                    }
                }

                $plugin_filter_names = RSSUtils::find_article_filters($article_filters, "plugin");
                $plugin_filter_actions = $pluginhost->get_filter_actions();

                if (count($plugin_filter_names) > 0) {
                    Debug::log("applying plugin filter actions...", Debug::$LOG_VERBOSE);

                    foreach ($plugin_filter_names as $pfn) {
                        list($pfclass, $pfaction) = explode(":", $pfn["param"]);

                        if (isset($plugin_filter_actions[$pfclass])) {
                            $plugin = $pluginhost->get_plugin($pfclass);

                            Debug::log("... $pfclass: $pfaction", Debug::$LOG_VERBOSE);

                            if ($plugin) {
                                $start = microtime(true);
                                $article = $plugin->hook_article_filter_action($article, $pfaction);

                                Debug::log(sprintf("=== %.4f (sec)", microtime(true) - $start), Debug::$LOG_VERBOSE);
                            } else {
                                Debug::log("??? $pfclass: plugin object not found.", Debug::$LOG_VERBOSE);
                            }
                        } else {
                            Debug::log("??? $pfclass: filter plugin not registered.", Debug::$LOG_VERBOSE);
                        }
                    }
                }

                $entry_tags = $article["tags"];
                $entry_title = strip_tags($article["title"]);
                $entry_author = mb_substr(strip_tags($article["author"]), 0, 245);
                $entry_link = strip_tags($article["link"]);
                $entry_content = $article["content"]; // escaped below
                $entry_force_catchup = $article["force_catchup"];
                $article_labels = $article["labels"];
                $entry_score_modifier = (int) $article["score_modifier"];
                $entry_language = $article["language"];
                $entry_timestamp = $article["timestamp"];
                $num_comments = $article["num_comments"];

                if ($entry_timestamp == -1 || !$entry_timestamp || $entry_timestamp > time()) {
                    $entry_timestamp = time();
                }

                $entry_timestamp_fmt = strftime("%Y/%m/%d %H:%M:%S", $entry_timestamp);

                Debug::log("date $entry_timestamp [$entry_timestamp_fmt]", Debug::$LOG_VERBOSE);
                Debug::log("num_comments: $num_comments", Debug::$LOG_VERBOSE);

                if (Debug::get_loglevel() >= Debug::$LOG_EXTENDED) {
                    Debug::log("article labels:", Debug::$LOG_VERBOSE);

                    if (count($article_labels) != 0) {
                        print_r($article_labels);
                    }
                }

                Debug::log("force catchup: $entry_force_catchup", Debug::$LOG_VERBOSE);

                if ($cache_images) {
                                    RSSUtils::cache_media($entry_content, $site_url);
                }

                $csth = $pdo->prepare("SELECT id FROM ttrss_entries
					WHERE guid = ? OR guid = ?");
                $csth->execute([$entry_guid, $entry_guid_hashed]);

                if (!$row = $csth->fetch()) {

                    Debug::log("base guid [$entry_guid or $entry_guid_hashed] not found, creating...", Debug::$LOG_VERBOSE);

                    // base post entry does not exist, create it

                    $usth = $pdo->prepare(
                        "INSERT INTO ttrss_entries
							(title,
							guid,
							link,
							updated,
							content,
							content_hash,
							no_orig_date,
							date_updated,
							date_entered,
							comments,
							num_comments,
							plugin_data,
							lang,
							author)
						VALUES
							(?, ?, ?, ?, ?, ?,
							false,
							NOW(),
							?, ?, ?, ?,	?, ?)");

                        $usth->execute([$entry_title,
                            $entry_guid_hashed,
                            $entry_link,
                            $entry_timestamp_fmt,
                            "$entry_content",
                            $entry_current_hash,
                            $date_feed_processed,
                            $entry_comments,
                            (int) $num_comments,
                            $entry_plugin_data,
                            "$entry_language",
                            "$entry_author"]);

                }

                $csth->execute([$entry_guid, $entry_guid_hashed]);

                $entry_ref_id = 0;
                $entry_int_id = 0;

                if ($row = $csth->fetch()) {

                    Debug::log("base guid found, checking for user record", Debug::$LOG_VERBOSE);

                    $ref_id = $row['id'];
                    $entry_ref_id = $ref_id;

                    if (RSSUtils::find_article_filter($article_filters, "filter")) {
                        Debug::log("article is filtered out, nothing to do.", Debug::$LOG_VERBOSE);
                        $pdo->commit();
                        continue;
                    }

                    $score = RSSUtils::calculate_article_score($article_filters) + $entry_score_modifier;

                    Debug::log("initial score: $score [including plugin modifier: $entry_score_modifier]", Debug::$LOG_VERBOSE);

                    // check for user post link to main table

                    $sth = $pdo->prepare("SELECT ref_id, int_id FROM ttrss_user_entries WHERE
							ref_id = ? AND owner_uid = ?");
                    $sth->execute([$ref_id, $owner_uid]);

                    // okay it doesn't exist - create user entry
                    if ($row = $sth->fetch()) {
                        $entry_ref_id = $row["ref_id"];
                        $entry_int_id = $row["int_id"];

                        Debug::log("user record FOUND: RID: $entry_ref_id, IID: $entry_int_id", Debug::$LOG_VERBOSE);
                    } else {

                        Debug::log("user record not found, creating...", Debug::$LOG_VERBOSE);

                        if ($score >= -500 && !RSSUtils::find_article_filter($article_filters, 'catchup') && !$entry_force_catchup) {
                            $unread = 1;
                            $last_read_qpart = null;
                        } else {
                            $unread = 0;
                            $last_read_qpart = date("Y-m-d H:i"); // we can't use NOW() here because it gets quoted
                        }

                        if (RSSUtils::find_article_filter($article_filters, 'mark') || $score > 1000) {
                            $marked = 1;
                        } else {
                            $marked = 0;
                        }

                        if (RSSUtils::find_article_filter($article_filters, 'publish')) {
                            $published = 1;
                        } else {
                            $published = 0;
                        }

                        $last_marked = ($marked == 1) ? 'NOW()' : 'NULL';
                        $last_published = ($published == 1) ? 'NOW()' : 'NULL';

                        $sth = $pdo->prepare(
                            "INSERT INTO ttrss_user_entries
								(ref_id, owner_uid, feed_id, unread, last_read, marked,
								published, score, tag_cache, label_cache, uuid,
								last_marked, last_published)
							VALUES (?, ?, ?, ?, ?, ?, ?, ?, '', '', '', ".$last_marked.", ".$last_published.")");

                        $sth->execute([$ref_id, $owner_uid, $feed, $unread, $last_read_qpart, $marked,
                            $published, $score]);

                        $sth = $pdo->prepare("SELECT int_id FROM ttrss_user_entries WHERE
								ref_id = ? AND owner_uid = ? AND
								feed_id = ? LIMIT 1");

                        $sth->execute([$ref_id, $owner_uid, $feed]);

                        if ($row = $sth->fetch()) {
                                                    $entry_int_id = $row['int_id'];
                        }
                    }

                    Debug::log("resulting RID: $entry_ref_id, IID: $entry_int_id", Debug::$LOG_VERBOSE);

                    if (DB_TYPE == "pgsql") {
                                            $tsvector_qpart = "tsvector_combined = to_tsvector(:ts_lang, :ts_content),";
                    } else {
                                            $tsvector_qpart = "";
                    }

                    $sth = $pdo->prepare("UPDATE ttrss_entries
						SET title = :title,
							$tsvector_qpart
							content = :content,
							content_hash = :content_hash,
							updated = :updated,
							date_updated = NOW(),
							num_comments = :num_comments,
							plugin_data = :plugin_data,
							author = :author,
							lang = :lang
						WHERE id = :id");

                    $params = [":title" => $entry_title,
                        ":content" => "$entry_content",
                        ":content_hash" => $entry_current_hash,
                        ":updated" => $entry_timestamp_fmt,
                        ":num_comments" => (int) $num_comments,
                        ":plugin_data" => $entry_plugin_data,
                        ":author" => "$entry_author",
                        ":lang" => $entry_language,
                        ":id" => $ref_id];

                    if (DB_TYPE == "pgsql") {
                        $params[":ts_lang"] = $feed_language;
                        $params[":ts_content"] = mb_substr(strip_tags($entry_title." ".$entry_content), 0, 900000);
                    }

                    $sth->execute($params);

                    // update aux data
                    $sth = $pdo->prepare("UPDATE ttrss_user_entries
							SET score = ? WHERE ref_id = ?");
                    $sth->execute([$score, $ref_id]);

                    if ($mark_unread_on_update &&
                        !$entry_force_catchup &&
                        !RSSUtils::find_article_filter($article_filters, 'catchup')) {

                        Debug::log("article updated, marking unread as requested.", Debug::$LOG_VERBOSE);

                        $sth = $pdo->prepare("UPDATE ttrss_user_entries
							SET last_read = null, unread = true WHERE ref_id = ?");
                        $sth->execute([$ref_id]);
                    } else {
                        Debug::log("article updated, but we're forbidden to mark it unread.", Debug::$LOG_VERBOSE);
                    }
                }

                Debug::log("assigning labels [other]...", Debug::$LOG_VERBOSE);

                foreach ($article_labels as $label) {
                    Labels::add_article($entry_ref_id, $label[1], $owner_uid);
                }

                Debug::log("assigning labels [filters]...", Debug::$LOG_VERBOSE);

                RSSUtils::assign_article_to_label_filters($entry_ref_id, $article_filters,
                    $owner_uid, $article_labels);

                Debug::log("looking for enclosures...", Debug::$LOG_VERBOSE);

                // enclosures

                $enclosures = array();

                $encs = $item->get_enclosures();

                if (is_array($encs)) {
                    foreach ($encs as $e) {
                        $e_item = array(
                            rewrite_relative_url($site_url, $e->link),
                            $e->type, $e->length, $e->title, $e->width, $e->height);

                        // Yet another episode of "mysql utf8_general_ci is gimped"
                        if (DB_TYPE == "mysql" && MYSQL_CHARSET != "UTF8MB4") {
                            for ($i = 0; $i < count($e_item); $i++) {
                                if (is_string($e_item[$i])) {
                                    $e_item[$i] = RSSUtils::strip_utf8mb4($e_item[$i]);
                                }
                            }
                        }

                        array_push($enclosures, $e_item);
                    }
                }

                if ($cache_images) {
                                    RSSUtils::cache_enclosures($enclosures, $site_url);
                }

                if (Debug::get_loglevel() >= Debug::$LOG_EXTENDED) {
                    Debug::log("article enclosures:", Debug::$LOG_VERBOSE);
                    print_r($enclosures);
                }

                $esth = $pdo->prepare("SELECT id FROM ttrss_enclosures
						WHERE content_url = ? AND content_type = ? AND post_id = ?");

                $usth = $pdo->prepare("INSERT INTO ttrss_enclosures
							(content_url, content_type, title, duration, post_id, width, height) VALUES
							(?, ?, ?, ?, ?, ?, ?)");

                foreach ($enclosures as $enc) {
                    $enc_url = $enc[0];
                    $enc_type = $enc[1];
                    $enc_dur = (int) $enc[2];
                    $enc_title = $enc[3];
                    $enc_width = intval($enc[4]);
                    $enc_height = intval($enc[5]);

                    $esth->execute([$enc_url, $enc_type, $entry_ref_id]);

                    if (!$esth->fetch()) {
                        $usth->execute([$enc_url, $enc_type, (string) $enc_title, $enc_dur, $entry_ref_id, $enc_width, $enc_height]);
                    }
                }

                // check for manual tags (we have to do it here since they're loaded from filters)

                foreach ($article_filters as $f) {
                    if ($f["type"] == "tag") {

                        $manual_tags = trim_array(explode(",", $f["param"]));

                        foreach ($manual_tags as $tag) {
                            array_push($entry_tags, $tag);
                        }
                    }
                }

                // Skip boring tags

                $boring_tags = trim_array(explode(",", mb_strtolower(get_pref(
                    'BLACKLISTED_TAGS', $owner_uid, ''), 'utf-8')));

                $filtered_tags = array();
                $tags_to_cache = array();

                foreach ($entry_tags as $tag) {
                    if (array_search($tag, $boring_tags) === false) {
                        array_push($filtered_tags, $tag);
                    }
                }

                $filtered_tags = array_unique($filtered_tags);

                if (Debug::get_loglevel() >= Debug::$LOG_VERBOSE) {
                    Debug::log("filtered tags: ".implode(", ", $filtered_tags), Debug::$LOG_VERBOSE);

                }

                // Save article tags in the database

                if (count($filtered_tags) > 0) {

                    $tsth = $pdo->prepare("SELECT id FROM ttrss_tags
							WHERE tag_name = ? AND post_int_id = ? AND
							owner_uid = ? LIMIT 1");

                    $usth = $pdo->prepare("INSERT INTO ttrss_tags
									(owner_uid,tag_name,post_int_id)
									VALUES (?, ?, ?)");

                    $filtered_tags = FeedItem_Common::normalize_categories($filtered_tags);

                    foreach ($filtered_tags as $tag) {
                        $tsth->execute([$tag, $entry_int_id, $owner_uid]);

                        if (!$tsth->fetch()) {
                            $usth->execute([$owner_uid, $tag, $entry_int_id]);
                        }

                        array_push($tags_to_cache, $tag);
                    }

                    /* update the cache */
                    $tags_str = join(",", $tags_to_cache);

                    $tsth = $pdo->prepare("UPDATE ttrss_user_entries
						SET tag_cache = ? WHERE ref_id = ?
						AND owner_uid = ?");
                    $tsth->execute([$tags_str, $entry_ref_id, $owner_uid]);
                }

                Debug::log("article processed", Debug::$LOG_VERBOSE);

                $pdo->commit();
            }

            Debug::log("purging feed...", Debug::$LOG_VERBOSE);

            Feeds::purge_feed($feed, 0);

            $sth = $pdo->prepare("UPDATE ttrss_feeds
				SET last_updated = NOW(), last_unconditional = NOW(), last_error = '' WHERE id = ?");
            $sth->execute([$feed]);

        } else {

            $error_msg = mb_substr($rss->error(), 0, 245);

            Debug::log("fetch error: $error_msg", Debug::$LOG_VERBOSE);

            if (count($rss->errors()) > 1) {
                foreach ($rss->errors() as $error) {
                    Debug::log("+ $error", Debug::$LOG_VERBOSE);
                }
            }

            $sth = $pdo->prepare("UPDATE ttrss_feeds SET last_error = ?,
				last_updated = NOW(), last_unconditional = NOW() WHERE id = ?");
            $sth->execute([$error_msg, $feed]);

            unset($rss);

            Debug::log("update failed.", Debug::$LOG_VERBOSE);
            return false;
        }

        Debug::log("update done.", Debug::$LOG_VERBOSE);

        return true;
    }

    public static function cache_enclosures($enclosures, $site_url) {
        $cache = new DiskCache("images");

        if ($cache->isWritable()) {
            foreach ($enclosures as $enc) {

                if (preg_match("/(image|audio|video)/", $enc[1])) {
                    $src = rewrite_relative_url($site_url, $enc[0]);

                    $local_filename = sha1($src);

                    Debug::log("cache_enclosures: downloading: $src to $local_filename", Debug::$LOG_VERBOSE);

                    if (!$cache->exists($local_filename)) {

                        global $fetch_last_error_code;
                        global $fetch_last_error;

                        $file_content = fetch_file_contents(array("url" => $src,
                            "http_referrer" => $src,
                            "max_size" => MAX_CACHE_FILE_SIZE));

                        if ($file_content) {
                            $cache->put($local_filename, $file_content);
                        } else {
                            Debug::log("cache_enclosures: failed with $fetch_last_error_code: $fetch_last_error");
                        }
                    } else if (is_writable($local_filename)) {
                        $cache->touch($local_filename);
                    }
                }
            }
        }
    }

    public static function cache_media($html, $site_url) {
        $cache = new DiskCache("images");

        if ($cache->isWritable()) {
            $doc = new DOMDocument();
            if ($doc->loadHTML($html)) {
                $xpath = new DOMXPath($doc);

                $entries = $xpath->query('(//img[@src])|(//video/source[@src])|(//audio/source[@src])');

                foreach ($entries as $entry) {
                    if ($entry->hasAttribute('src') && strpos($entry->getAttribute('src'), "data:") !== 0) {
                        $src = rewrite_relative_url($site_url, $entry->getAttribute('src'));

                        $local_filename = sha1($src);

                        Debug::log("cache_media: checking $src", Debug::$LOG_VERBOSE);

                        if (!$cache->exists($local_filename)) {
                            Debug::log("cache_media: downloading: $src to $local_filename", Debug::$LOG_VERBOSE);

                            global $fetch_last_error_code;
                            global $fetch_last_error;

                            $file_content = fetch_file_contents(array("url" => $src,
                                "http_referrer" => $src,
                                "max_size" => MAX_CACHE_FILE_SIZE));

                            if ($file_content) {
                                $cache->put($local_filename, $file_content);
                            } else {
                                Debug::log("cache_media: failed with $fetch_last_error_code: $fetch_last_error");
                            }
                        } else if ($cache->isWritable($local_filename)) {
                            $cache->touch($local_filename);
                        }
                    }
                }
            }
        }
    }

    public static function expire_error_log() {
        Debug::log("Removing old error log entries...");

        $pdo = Db::pdo();

        if (DB_TYPE == "pgsql") {
            $pdo->query("DELETE FROM ttrss_error_log
				WHERE created_at < NOW() - INTERVAL '7 days'");
        } else {
            $pdo->query("DELETE FROM ttrss_error_log
				WHERE created_at < DATE_SUB(NOW(), INTERVAL 7 DAY)");
        }
    }

    public static function expire_feed_archive() {
        Debug::log("Removing old archived feeds...");

        $pdo = Db::pdo();

        if (DB_TYPE == "pgsql") {
            $pdo->query("DELETE FROM ttrss_archived_feeds
				WHERE created < NOW() - INTERVAL '1 month'");
        } else {
            $pdo->query("DELETE FROM ttrss_archived_feeds
				WHERE created < DATE_SUB(NOW(), INTERVAL 1 MONTH)");
        }
    }

    public static function expire_lock_files() {
        Debug::log("Removing old lock files...", Debug::$LOG_VERBOSE);

        $num_deleted = 0;

        if (is_writable(LOCK_DIRECTORY)) {
            $files = glob(LOCK_DIRECTORY."/*.lock");

            if ($files) {
                foreach ($files as $file) {
                    if (!file_is_locked(basename($file)) && time() - filemtime($file) > 86400 * 2) {
                        unlink($file);
                        ++$num_deleted;
                    }
                }
            }
        }

        Debug::log("removed $num_deleted old lock files.");
    }

    /**
     * Source: http://www.php.net/manual/en/function.parse-url.php#104527
     * Returns the url query as associative array
     *
     * @param    string    query
     * @return    array    params
     */
    public static function convertUrlQuery($query) {
        $queryParts = explode('&', $query);

        $params = array();

        foreach ($queryParts as $param) {
            $item = explode('=', $param);
            $params[$item[0]] = $item[1];
        }

        return $params;
    }

    public static function get_article_filters($filters, $title, $content, $link, $author, $tags, &$matched_rules = false, &$matched_filters = false) {
        $matches = array();

        foreach ($filters as $filter) {
            $match_any_rule = $filter["match_any_rule"];
            $inverse = $filter["inverse"];
            $filter_match = false;

            foreach ($filter["rules"] as $rule) {
                $match = false;
                $reg_exp = str_replace('/', '\/', $rule["reg_exp"]);
                $rule_inverse = $rule["inverse"];

                if (!$reg_exp) {
                                    continue;
                }

                switch ($rule["type"]) {
                case "title":
                    $match = @preg_match("/$reg_exp/iu", $title);
                    break;
                case "content":
                    // we don't need to deal with multiline regexps
                    $content = preg_replace("/[\r\n\t]/", "", $content);

                    $match = @preg_match("/$reg_exp/iu", $content);
                    break;
                case "both":
                    // we don't need to deal with multiline regexps
                    $content = preg_replace("/[\r\n\t]/", "", $content);

                    $match = (@preg_match("/$reg_exp/iu", $title) || @preg_match("/$reg_exp/iu", $content));
                    break;
                case "link":
                    $match = @preg_match("/$reg_exp/iu", $link);
                    break;
                case "author":
                    $match = @preg_match("/$reg_exp/iu", $author);
                    break;
                case "tag":
                    foreach ($tags as $tag) {
                        if (@preg_match("/$reg_exp/iu", $tag)) {
                            $match = true;
                            break;
                        }
                    }
                    break;
                }

                if ($rule_inverse) {
                    $match = !$match;
                }

                if ($match_any_rule) {
                    if ($match) {
                        $filter_match = true;
                        break;
                    }
                } else {
                    $filter_match = $match;
                    if (!$match) {
                        break;
                    }
                }
            }

            if ($inverse) {
                $filter_match = !$filter_match;
            }

            if ($filter_match) {
                if (is_array($matched_rules)) {
                    array_push($matched_rules, $rule);
                }
                if (is_array($matched_filters)) {
                    array_push($matched_filters, $filter);
                }

                foreach ($filter["actions"] as $action) {
                    array_push($matches, $action);

                    // if Stop action encountered, perform no further processing
                    if (isset($action["type"]) && $action["type"] == "stop") {
                        return $matches;
                    }
                }
            }
        }

        return $matches;
    }

    public static function find_article_filter($filters, $filter_name) {
        foreach ($filters as $f) {
            if ($f["type"] == $filter_name) {
                return $f;
            };
        }
        return false;
    }

    public static function find_article_filters($filters, $filter_name) {
        $results = array();

        foreach ($filters as $f) {
            if ($f["type"] == $filter_name) {
                array_push($results, $f);
            };
        }
        return $results;
    }

    public static function calculate_article_score($filters) {
        $score = 0;

        foreach ($filters as $f) {
            if ($f["type"] == "score") {
                $score += $f["param"];
            };
        }
        return $score;
    }

    public static function labels_contains_caption($labels, $caption) {
        foreach ($labels as $label) {
            if ($label[1] == $caption) {
                return true;
            }
        }

        return false;
    }

    public static function assign_article_to_label_filters($id, $filters, $owner_uid, $article_labels) {
        foreach ($filters as $f) {
            if ($f["type"] == "label") {
                if (!RSSUtils::labels_contains_caption($article_labels, $f["param"])) {
                    Labels::add_article($id, $f["param"], $owner_uid);
                }
            }
        }
    }

    public static function make_guid_from_title($title) {
        return preg_replace("/[ \"\',.:;]/", "-",
            mb_strtolower(strip_tags($title), 'utf-8'));
    }

    public static function cleanup_counters_cache() {
        $pdo = Db::pdo();

        $res = $pdo->query("DELETE FROM ttrss_counters_cache
			WHERE feed_id > 0 AND
			(SELECT COUNT(id) FROM ttrss_feeds WHERE
				id = feed_id AND
				ttrss_counters_cache.owner_uid = ttrss_feeds.owner_uid) = 0");

        $frows = $res->rowCount();

        $res = $pdo->query("DELETE FROM ttrss_cat_counters_cache
			WHERE feed_id > 0 AND
			(SELECT COUNT(id) FROM ttrss_feed_categories WHERE
				id = feed_id AND
				ttrss_cat_counters_cache.owner_uid = ttrss_feed_categories.owner_uid) = 0");

        $crows = $res->rowCount();

        Debug::log("removed $frows (feeds) $crows (cats) orphaned counter cache entries.");
    }

    public static function housekeeping_user($owner_uid) {
        $tmph = new PluginHost();

        load_user_plugins($owner_uid, $tmph);

        $tmph->run_hooks(PluginHost::HOOK_HOUSE_KEEPING, "hook_house_keeping", "");
    }

    public static function housekeeping_common() {
        DiskCache::expire();

        RSSUtils::expire_lock_files();
        RSSUtils::expire_error_log();
        RSSUtils::expire_feed_archive();
        RSSUtils::cleanup_feed_browser();

        Article::purge_orphans();
        RSSUtils::cleanup_counters_cache();

        PluginHost::getInstance()->run_hooks(PluginHost::HOOK_HOUSE_KEEPING, "hook_house_keeping", "");
    }

    public static function check_feed_favicon($site_url, $feed) {
        #		print "FAVICON [$site_url]: $favicon_url\n";

        $icon_file = ICONS_DIR."/$feed.ico";

        if (!file_exists($icon_file)) {
            $favicon_url = RSSUtils::get_favicon_url($site_url);

            if ($favicon_url) {
                // Limiting to "image" type misses those served with text/plain
                $contents = fetch_file_contents($favicon_url); // , "image");

                if ($contents) {
                    // Crude image type matching.
                    // Patterns gleaned from the file(1) source code.
                    if (preg_match('/^\x00\x00\x01\x00/', $contents)) {
                        // 0       string  \000\000\001\000        MS Windows icon resource
                        //error_log("check_feed_favicon: favicon_url=$favicon_url isa MS Windows icon resource");
                    } elseif (preg_match('/^GIF8/', $contents)) {
                        // 0       string          GIF8            GIF image data
                        //error_log("check_feed_favicon: favicon_url=$favicon_url isa GIF image");
                    } elseif (preg_match('/^\x89PNG\x0d\x0a\x1a\x0a/', $contents)) {
                        // 0       string          \x89PNG\x0d\x0a\x1a\x0a         PNG image data
                        //error_log("check_feed_favicon: favicon_url=$favicon_url isa PNG image");
                    } elseif (preg_match('/^\xff\xd8/', $contents)) {
                        // 0       beshort         0xffd8          JPEG image data
                        //error_log("check_feed_favicon: favicon_url=$favicon_url isa JPG image");
                    } elseif (preg_match('/^BM/', $contents)) {
                        // 0	string		BM	PC bitmap (OS2, Windows BMP files)
                        //error_log("check_feed_favicon, favicon_url=$favicon_url isa BMP image");
                    } else {
                        //error_log("check_feed_favicon: favicon_url=$favicon_url isa UNKNOWN type");
                        $contents = "";
                    }
                }

                if ($contents) {
                    $fp = @fopen($icon_file, "w");

                    if ($fp) {
                        fwrite($fp, $contents);
                        fclose($fp);
                        chmod($icon_file, 0644);
                    }
                }
            }
            return $icon_file;
        }
    }

    public static function is_gzipped($feed_data) {
        return strpos(substr($feed_data, 0, 3),
                "\x1f"."\x8b"."\x08", 0) === 0;
    }

    public static function load_filters($feed_id, $owner_uid) {
        $filters = array();

        $feed_id = (int) $feed_id;
        $cat_id = (int) Feeds::getFeedCategory($feed_id);

        if ($cat_id == 0) {
                    $null_cat_qpart = "cat_id IS NULL OR";
        } else {
                    $null_cat_qpart = "";
        }

        $pdo = Db::pdo();

        $sth = $pdo->prepare("SELECT * FROM ttrss_filters2 WHERE
				owner_uid = ? AND enabled = true ORDER BY order_id, title");
        $sth->execute([$owner_uid]);

        $check_cats = array_merge(
            Feeds::getParentCategories($cat_id, $owner_uid),
            [$cat_id]);

        $check_cats_str = join(",", $check_cats);
        $check_cats_fullids = array_map(function($a) { return "CAT:$a"; }, $check_cats);

        while ($line = $sth->fetch()) {
            $filter_id = $line["id"];

            $match_any_rule = sql_bool_to_bool($line["match_any_rule"]);

            $sth2 = $pdo->prepare("SELECT
					r.reg_exp, r.inverse, r.feed_id, r.cat_id, r.cat_filter, r.match_on, t.name AS type_name
					FROM ttrss_filters2_rules AS r,
					ttrss_filter_types AS t
					WHERE
						(match_on IS NOT NULL OR
						  (($null_cat_qpart (cat_id IS NULL AND cat_filter = false) OR cat_id IN ($check_cats_str)) AND
						  (feed_id IS NULL OR feed_id = ?))) AND
						filter_type = t.id AND filter_id = ?");
            $sth2->execute([$feed_id, $filter_id]);

            $rules = array();
            $actions = array();

            while ($rule_line = $sth2->fetch()) {
                #				print_r($rule_line);

                if ($rule_line["match_on"]) {
                    $match_on = json_decode($rule_line["match_on"], true);

                    if (in_array("0", $match_on) || in_array($feed_id, $match_on) || count(array_intersect($check_cats_fullids, $match_on)) > 0) {

                        $rule = array();
                        $rule["reg_exp"] = $rule_line["reg_exp"];
                        $rule["type"] = $rule_line["type_name"];
                        $rule["inverse"] = sql_bool_to_bool($rule_line["inverse"]);

                        array_push($rules, $rule);
                    } else if (!$match_any_rule) {
                        // this filter contains a rule that doesn't match to this feed/category combination
                        // thus filter has to be rejected

                        $rules = [];
                        break;
                    }

                } else {

                    $rule = array();
                    $rule["reg_exp"] = $rule_line["reg_exp"];
                    $rule["type"] = $rule_line["type_name"];
                    $rule["inverse"] = sql_bool_to_bool($rule_line["inverse"]);

                    array_push($rules, $rule);
                }
            }

            if (count($rules) > 0) {
                $sth2 = $pdo->prepare("SELECT a.action_param,t.name AS type_name
						FROM ttrss_filters2_actions AS a,
						ttrss_filter_actions AS t
						WHERE
							action_id = t.id AND filter_id = ?");
                $sth2->execute([$filter_id]);

                while ($action_line = $sth2->fetch()) {
                    #				print_r($action_line);

                    $action = array();
                    $action["type"] = $action_line["type_name"];
                    $action["param"] = $action_line["action_param"];

                    array_push($actions, $action);
                }
            }

            $filter = [];
            $filter["id"] = $filter_id;
            $filter["match_any_rule"] = sql_bool_to_bool($line["match_any_rule"]);
            $filter["inverse"] = sql_bool_to_bool($line["inverse"]);
            $filter["rules"] = $rules;
            $filter["actions"] = $actions;

            if (count($rules) > 0 && count($actions) > 0) {
                array_push($filters, $filter);
            }
        }

        return $filters;
    }

    /**
     * Try to determine the favicon URL for a feed.
     * adapted from wordpress favicon plugin by Jeff Minard (http://thecodepro.com/)
     * http://dev.wp-plugins.org/file/favatars/trunk/favatars.php
     *
     * @param string $url A feed or page URL
     * @access public
     * @return mixed The favicon URL, or false if none was found.
     */
    public static function get_favicon_url($url) {

        $favicon_url = false;

        if ($html = @fetch_file_contents($url)) {

            $doc = new DOMDocument();
            if ($doc->loadHTML($html)) {
                $xpath = new DOMXPath($doc);

                $base = $xpath->query('/html/head/base[@href]');
                foreach ($base as $b) {
                    $url = rewrite_relative_url($url, $b->getAttribute("href"));
                    break;
                }

                $entries = $xpath->query('/html/head/link[@rel="shortcut icon" or @rel="icon"]');
                if (count($entries) > 0) {
                    foreach ($entries as $entry) {
                        $favicon_url = rewrite_relative_url($url, $entry->getAttribute("href"));
                        break;
                    }
                }
            }
        }

        if (!$favicon_url) {
                    $favicon_url = rewrite_relative_url($url, "/favicon.ico");
        }

        return $favicon_url;
    }

}