Reverse proxying share.dmhy.org

worker.js

export default {
  /**
   * Default fetch event handler
   * @param request {Request}
   * @param env 
   * @param ctx 
   * @returns {Promise<Response>}
   */
  async fetch(request, env, ctx) {
    const url = new URL(request.url);
    // handling direct url revese proxying
    // only proxying 'dl.dmhy.org'
    if (url.pathname.match(/^\/https?:\/\/dl\.dmhy\.org/)) {
      const link = url.pathname.slice(1);
      return fetch(link, request);
    }
    // proxy other requests to 'share.dmhy.org'; don't forget headers (cookies)
    const response = await fetch(new URL(url.pathname + url.search, 'https://share.dmhy.org'), request);
    // if response is text/html, altering its content
    if (response.headers.get('Content-Type')?.includes('text/html')) {
      // getting html text
      const html = await response.text();
      // adding CSP header
      const headers = new Headers(response.headers);
      headers.set('Content-Security-Policy', `script-src ${url.origin} 'unsafe-inline' 'unsafe-eval' https://js.kiwihk.net/ ; style-src 'self' 'unsafe-inline' https://js.kiwihk.net/ `);
      return new Response(
        html
        // modifying title, adding "no-referrer", adding custom style
        .replace(/(<\s*title[^>]*>)([^<]*)(<\/\s*title[^>]*>)/, `$1 (镜像) $2 (Powered by Cloudflare Workers)$3
          <meta name="referrer" content="no-referrer" />
          <style> img {max-width: 100%;} </style>
        `)
        // replacing links to / text of (sub-)domains on page
        // .replaceAll(/(?<!\.)(?:(?:share\.|www\.)?dmhy\.org)/g, url.host)
        // modifying 'dl.dmhy.org' links on page
        .replaceAll(/(href=")((?:https?:)?\/\/dl\.dmhy\.org)/g, (_match, p1, p2) => p2.startsWith('//') ? `${p1}/https:${p2}` : `${p1}/${p2}`)
        , {
          headers,
          status: response.status,
        }
      );
    }
    return response;
  },
};