Proxy with Cloudflare Workers

If your domain is on Cloudflare, a Worker on one route serves the script and events and passes Cloudflare's own visitor location.

Set it up

1. Create the Worker

   src/index.js

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   // src/index.js · Cloudflare Worker on the route example.com/a/*
   export default {
     async fetch(request) {
       const { pathname } = new URL(request.url);
       const script = pathname === "/a/script" && request.method === "GET";
       const event = pathname === "/a/event" && request.method === "POST";
       if (!script && !event) return new Response("Not found", { status: 404 });
       const headers = new Headers();
       for (const name of ["content-type", "origin", "user-agent"]) {
         const value = request.headers.get(name);
         if (value) headers.set(name, value);
       }
       const ip = request.headers.get("cf-connecting-ip");
       if (ip) headers.set("x-visitor-ip", ip);
       // Cloudflare's location for this visitor. Names are URL-encoded so accented cities survive.
       const cf = request.cf || {};
       for (const [name, value] of [
         ["x-visitor-country", cf.country],
         ["x-visitor-region", cf.region],
         ["x-visitor-city", cf.city],
         ["x-visitor-latitude", cf.latitude],
         ["x-visitor-longitude", cf.longitude],
       ]) {
         if (ip && value) headers.set(name, encodeURIComponent(value));
       }
       const upstream = await fetch(script ? "https://metricraven.com/js/script.js" : "https://metricraven.com/api/v1/collect", {
         method: request.method,
         headers,
         body: event ? await request.arrayBuffer() : undefined,
       });
       return new Response(upstream.body, {
         status: upstream.status,
         headers: {
           "Content-Type": upstream.headers.get("content-type") || "application/octet-stream",
           "Cache-Control": script ? "public, max-age=3600" : "no-store",
         },
       });
     },
   };

2. Route it to /a/* on your domain

   Replace both example.com values with your domain, then deploy:

   wrangler.toml

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   # wrangler.toml
   name = "metricraven-proxy"
   main = "src/index.js"
   compatibility_date = "2026-10-01"
   
   [[routes]]
   pattern = "example.com/a/*"
   zone_name = "example.com"

   terminal

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   npx wrangler deploy

   You can also add the route in the Cloudflare dashboard, under the Worker's Settings → Domains & Routes.

3. Point your script tag at your own paths

   Replace your MetricRaven tag with this one. src loads the tracker from your domain and data-api sends its events there too.

   Your website's shared layout

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   <script defer src="/a/script" data-api="/a/event" data-site-id="YOUR_SITE_ID"></script>

Notes

• The domain must be proxied through Cloudflare (orange cloud) for a Worker route to run on it.
• cf-connecting-ip is set by Cloudflare and can't be faked by visitors. It must still be sent as x-visitor-ip: requests from your Worker reach MetricRaven with the Worker's address as the connecting IP.
• If the route pattern is wider than /a/script and /a/event, the Worker answers other /a/ paths with 404. Pick a prefix your site doesn't use.

How the proxy works and which headers it must send: Use your own domain.