marketing: route posthog proxy under /_astro so it works on executor.sh

Cloud owns the executor.sh apex (custom domain) and only forwards an allow-list (including /_astro) to the marketing worker, so the prior /api/a proxy path 404d on the live domain and no events sent. Move the proxy to /_astro/_ph, which rides the forwarded prefix and is intercepted by the marketing middleware before any asset lookup. Also attach the analytics:capture listener synchronously so a click during posthog js async load is not dropped. Verified end to end: a capture POSTed through executor.sh/_astro/_ph/e/ lands in the Production project.

Author: RhysSullivan

apps/marketing/src/layouts/Layout.astro

@@ -55,29 +55,30 @@ const canonical = new URL(Astro.url.pathname, Astro.site ?? Astro.url).toString(
       // capture_pageview on if you want a denominator for conversion.
       const phKey = import.meta.env.PUBLIC_POSTHOG_KEY;
       if (phKey) {
-        const phPath = (import.meta.env.PUBLIC_ANALYTICS_PATH ?? "a").replace(
-          /^\/+|\/+$/g,
-          "",
-        );
-        void import("posthog-js").then(({ default: posthog }) => {
+        // api_host rides the `/_astro` prefix that the cloud edge forwards to
+        // this worker on executor.sh; src/middleware.ts proxies it to PostHog.
+        const posthogReady = import("posthog-js").then(({ default: posthog }) => {
           posthog.init(phKey, {
-            api_host: `${window.location.origin}/api/${phPath}`,
+            api_host: `${window.location.origin}/_astro/_ph`,
             ui_host: import.meta.env.PUBLIC_POSTHOG_HOST ?? "https://us.posthog.com",
             autocapture: false,
             capture_pageview: false,
             persistence: "localStorage",
           });
-          // The copy handler (in index.astro) is a separate bundle, so it asks
-          // for a capture via a DOM event rather than reaching for a global.
-          window.addEventListener("analytics:capture", (e) => {
-            const detail = (
-              e as CustomEvent<{
-                event: string;
-                properties?: Record<string, unknown>;
-              }>
-            ).detail;
-            posthog.capture(detail.event, detail.properties);
-          });
+          return posthog;
+        });
+        // The copy handler (in index.astro) is a separate bundle, so it asks for
+        // a capture via a DOM event rather than reaching for a global. Attached
+        // synchronously so a click during PostHog's async load isn't missed; the
+        // capture waits on the init promise.
+        window.addEventListener("analytics:capture", (e) => {
+          const detail = (
+            e as CustomEvent<{
+              event: string;
+              properties?: Record<string, unknown>;
+            }>
+          ).detail;
+          void posthogReady.then((posthog) => posthog.capture(detail.event, detail.properties));
         });
       }
     </script>

apps/marketing/src/middleware.ts

@@ -1,16 +1,18 @@
 import type { MiddlewareHandler } from "astro";
 
-// PostHog reverse proxy — the browser SDK targets a build-randomized
-// first-party path and we forward to PostHog's ingest + asset hosts. Keeps
-// events flowing past adblockers that match *.posthog.com. See
+// PostHog reverse proxy — the browser SDK targets a first-party path and we
+// forward to PostHog's ingest + asset hosts. Keeps events flowing past
+// adblockers that match *.posthog.com. See
 // https://posthog.com/docs/advanced/proxy/cloudflare
-
+//
+// The path MUST sit under a prefix that the cloud worker's edge forwards to
+// this worker. On the production apex (executor.sh) the cloud worker owns the
+// custom domain and only proxies an allow-list to executor-marketing; `/api/*`
+// stays in cloud (it has its own posthog proxy on a randomized path), so a
+// top-level `/api/...` path here 404s. `/_astro` IS forwarded, so we ride it.
 const POSTHOG_INGEST_HOST = "us.i.posthog.com";
 const POSTHOG_ASSETS_HOST = "us-assets.i.posthog.com";
-const POSTHOG_PROXY_PATH = `/api/${(import.meta.env.PUBLIC_ANALYTICS_PATH ?? "a").replace(
-  /^\/+|\/+$/g,
-  "",
-)}`;
+const POSTHOG_PROXY_PATH = "/_astro/_ph";
 
 export const onRequest: MiddlewareHandler = async (context, next) => {
   const { pathname } = new URL(context.request.url);