Cloudflare Worker Setup

export default {
  async fetch(request, env, ctx) {
    const ORIGIN_HOST = "seo-tools-container.onrender.com";   // Render upstream
    const PREFIX = "/tools";                                   // mount path

    const url = new URL(request.url);
    const isPrefixed = url.pathname === PREFIX || url.pathname.startsWith(PREFIX + "/");

    // Normalize /tools/ → /tools
    if (url.pathname === PREFIX + "/") {
      url.pathname = PREFIX;
      return Response.redirect(url.toString(), 301);
    }

    // Not our path? pass through unchanged
    if (!isPrefixed) return fetch(request);

    // Build upstream URL: strip the /tools prefix
    const upstream = new URL(url.toString());
    upstream.hostname = ORIGIN_HOST;
    upstream.pathname = url.pathname.replace(/^\/tools(\/?)/, "/") || "/";

    // Forward request
    const init = {
      method: request.method,
      headers: new Headers(request.headers),
      body: ["GET", "HEAD"].includes(request.method) ? undefined : await request.arrayBuffer(),
      redirect: "manual",
    };
    init.headers.set("X-Forwarded-Host", url.host);
    init.headers.set("X-Forwarded-Proto", url.protocol.replace(":", ""));
    init.headers.set("Host", ORIGIN_HOST);

    let resp = await fetch(upstream.toString(), init);

    // Rewrite upstream redirects to /tools/...
    const loc = resp.headers.get("Location");
    if (loc) {
      const abs = new URL(loc, upstream);
      if (abs.hostname === ORIGIN_HOST) {
        const rewritten = PREFIX + (abs.pathname === "/" ? "" : abs.pathname) + (abs.search || "");
        const r = new Response(null, { status: resp.status, headers: resp.headers });
        r.headers.set("Location", rewritten);
        return r;
      }
    }

    // Cookie scope fix (auth/session under /tools)
    const out = new Response(resp.body, resp);
    const getAll = out.headers.getAll
      ? (h) => out.headers.getAll(h)
      : (h) => (out.headers.get(h) ? [out.headers.get(h)] : []);
    const setCookies = getAll("Set-Cookie");
    if (setCookies.length) {
      out.headers.delete("Set-Cookie");
      for (let c of setCookies) {
        // Domain rewrite: seo-tools-container.onrender.com → user's domain
        c = c.replace(/;\s*Domain=seo-tools-container\.onrender\.com/gi, `; Domain=${url.hostname}`);
        // Ensure cookies are scoped to /tools (avoid site-wide leakage)
        c = c.replace(/;\s*Path=\/(?!tools\b)/i, `; Path=${PREFIX}`);
        if (!/;\s*Path=/i.test(c)) c += `; Path=${PREFIX}`;
        out.headers.append("Set-Cookie", c);
      }
    }

    return out;
  }
};