initial commit

fluxer_api/src/utils/UnfurlerUtils.ts

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+/*
+ * Copyright (C) 2026 Fluxer Contributors
+ *
+ * This file is part of Fluxer.
+ *
+ * Fluxer 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.
+ *
+ * Fluxer 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 Fluxer. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import * as idna from 'idna-uts46-hx';
+import {Config} from '~/Config';
+import {URL_REGEX} from '~/Constants';
+import {Logger} from '~/Logger';
+import * as InviteUtils from '~/utils/InviteUtils';
+
+const MARKETING_PATH_PREFIXES = ['/channels/', '/theme/'];
+
+const WEB_APP_HOSTNAME = (() => {
+	try {
+		return new URL(Config.endpoints.webApp).hostname;
+	} catch {
+		return '';
+	}
+})();
+
+const EXCLUDED_HOSTNAMES = new Set<string>();
+
+const normalizeHostname = (hostname: string | undefined) => hostname?.trim().toLowerCase() || '';
+const MARKETING_HOSTNAME = normalizeHostname(Config.hosts.marketing);
+const isMarketingPath = (hostname: string, pathname: string) =>
+	hostname === MARKETING_HOSTNAME && MARKETING_PATH_PREFIXES.some((prefix) => pathname.startsWith(prefix));
+
+const addHostname = (hostname: string | undefined) => {
+	const normalized = normalizeHostname(hostname);
+	if (!normalized) return;
+	EXCLUDED_HOSTNAMES.add(normalized);
+};
+
+addHostname(Config.hosts.invite);
+addHostname(Config.hosts.gift);
+Config.hosts.unfurlIgnored.forEach(addHostname);
+addHostname(WEB_APP_HOSTNAME);
+
+export const idnaEncodeURL = (url: string) => {
+	try {
+		const parsedUrl = new URL(url);
+		const encodedDomain = idna.toAscii(parsedUrl.hostname).toLowerCase();
+		parsedUrl.hostname = encodedDomain;
+		parsedUrl.username = '';
+		parsedUrl.password = '';
+		return parsedUrl.toString();
+	} catch (error) {
+		Logger.error({error}, 'Failed to encode URL');
+		return '';
+	}
+};
+
+export const isValidURL = (url: string) => {
+	try {
+		const parsedUrl = new URL(url);
+		return parsedUrl.protocol === 'http:' || parsedUrl.protocol === 'https:';
+	} catch {
+		return false;
+	}
+};
+
+export const isFluxerAppExcludedURL = (url: string) => {
+	try {
+		const parsedUrl = new URL(url);
+		const hostname = normalizeHostname(parsedUrl.hostname);
+		const isMarketingPathMatch = isMarketingPath(hostname, parsedUrl.pathname);
+
+		return isMarketingPathMatch || EXCLUDED_HOSTNAMES.has(hostname);
+	} catch {
+		return false;
+	}
+};
+
+export const extractURLs = (inputText: string) => {
+	let text = inputText;
+	text = text.replace(/`[^`]*`/g, '');
+	text = text.replace(/```.*?```/gs, '');
+	text = text.replace(/\|\|([\s\S]*?)\|\|/g, ' $1 ');
+	text = text.replace(/\|\|/g, ' ');
+	text = text.replace(/\[([^\]]+)\]\((https?:\/\/[^\s)]+)\)/g, '$2');
+	text = text.replace(/<https?:\/\/[^\s]+>/g, '');
+	const urls = text.match(URL_REGEX) || [];
+	const validURLs = urls.filter(isValidURL);
+	const filteredURLs = validURLs
+		.filter((url) => InviteUtils.findInvite(url) == null)
+		.filter((url) => !isFluxerAppExcludedURL(url));
+	const encodedURLs = filteredURLs.map(idnaEncodeURL).filter(Boolean);
+	const uniqueURLs = Array.from(new Set(encodedURLs));
+	return uniqueURLs.slice(0, 5);
+};