outline/shared/utils/domains.ts

import { trim } from "lodash";

type Domain = {
  tld: string;
  subdomain: string;
  domain: string;
};

// we originally used the parse-domain npm module however this includes
// a large list of possible TLD's which increase the size of the bundle
// unnecessarily for our usecase of trusted input.
export function parseDomain(url?: string): Domain | null | undefined {
  if (typeof url !== "string") {
    return null;
  }
  if (url === "") {
    return null;
  }

  // strip extermeties and whitespace from input
  const normalizedDomain = trim(url.replace(/(https?:)?\/\//, ""));
  const parts = normalizedDomain.split(".");

  // ensure the last part only includes something that looks like a TLD
  function cleanTLD(tld = "") {
    return tld.split(/[/:?]/)[0];
  }

  // simplistic subdomain parse, we don't need to take into account subdomains
  // with "." characters as these are not valid in Outline
  if (parts.length >= 3) {
    return {
      subdomain: parts[0],
      domain: parts[1],
      tld: cleanTLD(parts.slice(2).join(".")),
    };
  }

  if (parts.length === 2) {
    return {
      subdomain: "",
      domain: parts[0],
      tld: cleanTLD(parts.slice(1).join(".")),
    };
  }

  // one-part domain handler for things like localhost
  if (parts.length === 1) {
    return {
      subdomain: "",
      domain: cleanTLD(parts.slice(0).join()),
      tld: "",
    };
  }

  return null;
}

export function stripSubdomain(hostname: string) {
  const parsed = parseDomain(hostname);
  if (!parsed) {
    return hostname;
  }
  if (parsed.tld) {
    return `${parsed.domain}.${parsed.tld}`;
  }
  return parsed.domain;
}

export function isCustomSubdomain(hostname: string) {
  const parsed = parseDomain(hostname);

  if (
    !parsed ||
    !parsed.subdomain ||
    parsed.subdomain === "app" ||
    parsed.subdomain === "www"
  ) {
    return false;
  }

  return true;
}

export const RESERVED_SUBDOMAINS = [
  "about",
  "account",
  "admin",
  "advertising",
  "api",
  "app",
  "assets",
  "archive",
  "beta",
  "billing",
  "blog",
  "cache",
  "cdn",
  "code",
  "community",
  "dashboard",
  "developer",
  "developers",
  "forum",
  "help",
  "home",
  "http",
  "https",
  "imap",
  "localhost",
  "mail",
  "marketing",
  "mobile",
  "multiplayer",
  "new",
  "news",
  "newsletter",
  "ns1",
  "ns2",
  "ns3",
  "ns4",
  "password",
  "profile",
  "realtime",
  "sandbox",
  "script",
  "scripts",
  "setup",
  "signin",
  "signup",
  "site",
  "smtp",
  "support",
  "status",
  "static",
  "stats",
  "test",
  "update",
  "updates",
  "ws",
  "wss",
  "web",
  "websockets",
  "www",
  "www1",
  "www2",
  "www3",
  "www4",
];