Respond with another site

export default {
  async fetch(request): Promise<Response> {
    async function MethodNotAllowed(request) {
      return new Response(`Method ${request.method} not allowed.`, {
        status: 405,
        headers: {
          Allow: "GET",
        },
      });
    }
    // Only GET requests work with this proxy.
    if (request.method !== "GET") return MethodNotAllowed(request);
    return fetch(`https://example.com`);
  },
} satisfies ExportedHandler;

from js import Response, fetch, Headers

def on_fetch(request):
    def method_not_allowed(request):
        msg = f'Method {request.method} not allowed.'
        headers = Headers.new({"Allow": "GET"}.items)
        return Response.new(msg, headers=headers, status=405)

    # Only GET requests work with this proxy.
    if request.method != "GET":
        return method_not_allowed(request)

    return fetch("https://example.com")