利用 Cloudflare Workers 为 Bento 创建自定义域名

const BENTO_USERNAME = 'singee'
const BASE_URL = "https://singee.me"

export default {
  async fetch(request, env, ctx) {
    return handleRequest(request);
  },
};

async function handleRequest(request) {
  // Extracts the path from the request URL
  const path = new URL(request.url).pathname;
  // By default, the URL is set to 'https://bento.me'
  // appended with the path
  let url = 'https://bento.me' + path;

  // If the path includes 'v1', the URL is changed to
  // 'https://api.bento.me' appended with the path
  if (path.includes('v1')) {
    url = 'https://api.bento.me' + path;
  }

  // If the URL is 'https://bento.me/' the URL is changed to
  // 'https://bento.me/' appended with the BENTO_USERNAME
  if (url === 'https://bento.me/') {
    url = 'https://bento.me/' + BENTO_USERNAME;
  }

  // Basic headers for the fetch request are defined
  let headers = {
    'Access-Control-Allow-Origin': '*',
    'Access-Control-Allow-Methods': 'GET,HEAD,POST,OPTIONS',
  };

  // The URL is fetched with the defined headers
  const response = await fetch(url, { headers });

  // The content type is extracted from the response headers
  const contentType = response.headers.get('content-type');

  // The response is parsed based on its content type
  let results = await parseResponseByContentType(response, contentType);

  // If the results are not an ArrayBuffer
  // all calls to the bento API are replaced with our BASE_URL
  // This is a workaround to fix CORS errors that occur otherwise
  if (!(results instanceof ArrayBuffer)) {
    results = results.replaceAll('https://api.bento.me', BASE_URL);
  }

  // The content type is added to the headers
  headers['content-type'] = contentType;

  // A new response is returned with the results and headers
  return new Response(results, { headers });
}

  async function parseResponseByContentType(response, contentType) {
    // If there's no content type, the response is returned as text
    if (!contentType) return await response.text();

    // Depending on the content type, different actions are taken
    switch (true) {
      case contentType.includes('application/json'):
        // If the content type is JSON, the response is returned as a JSON string
        return JSON.stringify(await response.json());
      case contentType.includes('text/html'):
        const transformedResponse = new HTMLRewriter()
          .on('body', {
            element(element) {
              element.append(
                `
                  <style>
                    main>div.fixed {display: none}
                  </style>
                  `,
                { html: true },
              );
            },
          })
          .transform(response);
        // The transformed response is returned as text
        return await transformedResponse.text();

      case contentType.includes('font'):
        // If the content type is a font, the response is returned as an ArrayBuffer
        return await response.arrayBuffer();

      case contentType.includes('image'):
        // If the content type is an image, the response is returned as an ArrayBuffer
        return await response.arrayBuffer()

      default:
        // If the content type is anything else, the response is returned as text
        return await response.text();
    }
  }