#Cloudflare Worker

npm create cloudflare@latest x3-proxy -- --type=hello-world --lang=ts
cd x3-proxy
npx wrangler secret put X3_PROXY_KEY

export interface Env {
  X3_API_ORIGIN: string;
  X3_PROXY_KEY: string;
  PROXY_PATH: string;
}

const ALLOWED = /^\/v1\/(?:e|collect|cb|c\/[^/]+|s\/[A-Za-z0-9@._-]+)$/;

export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext): Promise<Response> {
    const url = new URL(request.url);
    const path = url.pathname.slice(env.PROXY_PATH.length);
    if (!url.pathname.startsWith(env.PROXY_PATH) || !ALLOWED.test(path)) return new Response("not found", { status: 404 });

    const target = new URL(path + url.search, env.X3_API_ORIGIN);
    const isScript = path.startsWith("/v1/s/");
    const cache = caches.default;
    if (isScript && request.method === "GET") {
      const hit = await cache.match(request);
      if (hit) return hit;
    }

    const headers = new Headers();
    for (const name of ["user-agent", "origin", "content-type", "accept", "sec-fetch-site", "sec-gpc", "dnt"]) {
      const value = request.headers.get(name);
      if (value) headers.set(name, value);
    }
    headers.set("x-3x-client-ip", request.headers.get("cf-connecting-ip") ?? "");
    headers.set("x-3x-client-country", request.headers.get("cf-ipcountry") ?? "");
    headers.set("x-3x-proxy-key", env.X3_PROXY_KEY);

    const upstream = await fetch(target, {
      method: request.method,
      headers,
      body: request.method === "POST" ? await request.arrayBuffer() : undefined,
      redirect: "manual",
    });
    const response = new Response(upstream.body, upstream);
    response.headers.delete("set-cookie");
    if (isScript && upstream.ok) {
      response.headers.set("cache-control", "public, max-age=3600, stale-while-revalidate=86400");
      ctx.waitUntil(cache.put(request, response.clone()));
    }
    return response;
  },
};

name = "x3-proxy"
main = "src/index.ts"
compatibility_date = "2026-10-01"
routes = [{ pattern = "example.com{{PROXY_PATH}}/*", zone_name = "example.com" }]

[vars]
X3_API_ORIGIN = "{{API_ORIGIN}}"
PROXY_PATH = "{{PROXY_PATH}}"

npx wrangler deploy

curl -s -o /dev/null -w "%{http_code}\n" https://example.com{{PROXY_PATH}}/v1/s/x3.js