Proxying ntc.party through CF workers

worker.js

export default {
  async fetch(request) {
    const url = new URL(request.url);
    const workerHost = url.host;
    const targetHost = 'ntc.party';

    if (url.pathname === '/robots.txt') {
      return new Response('User-agent: *\nDisallow: /', {
        headers: { 'Content-Type': 'text/plain' }
      });
    }

    url.hostname = targetHost;
    url.protocol = 'https:';

    const newHeaders = new Headers(request.headers);
    newHeaders.set('Host', targetHost);
    newHeaders.set('Origin', `https://${targetHost}`);
    newHeaders.set('Referer', `https://${targetHost}/`);

    const newRequest = new Request(url, {
      method: request.method,
      headers: newHeaders,
      body: request.body,
      redirect: 'manual'
    });

    const response = await fetch(newRequest);

    const newResponseHeaders = new Headers(response.headers);
    newResponseHeaders.set('X-Robots-Tag', 'noindex, nofollow, noarchive');
    
    const contentType = newResponseHeaders.get('content-type');
    
    if (contentType && (contentType.includes('text/html') || contentType.includes('text/css') || contentType.includes('application/json') || contentType.includes('javascript'))) {
      let bodyText = await response.text();

      const from = `https://${targetHost}`;
      const to = `https://${workerHost}`;

      bodyText = bodyText.replaceAll(`="${from}`, `="${to}`);
      bodyText = bodyText.replaceAll(`='${from}`, `='${to}`);
      bodyText = bodyText.replaceAll(`("${from}`, `("${to}`);
      bodyText = bodyText.replaceAll(`('${from}`, `('${to}`);
      bodyText = bodyText.replaceAll(`=\\"${from}`, `=\\"${to}`);
      bodyText = bodyText.replaceAll(`"${from}`, `"${to}`);
      bodyText = bodyText.replaceAll(`u003e${from}`, `u003e${to}`);
      
      return new Response(bodyText, {
        status: response.status,
        statusText: response.statusText,
        headers: newResponseHeaders
      });
    }

    return new Response(response.body, {
      status: response.status,
      statusText: response.statusText,
      headers: newResponseHeaders
    });
  }
};