init

workers/analytics/analytics_worker.js

@@ -0,0 +1,87 @@
+addEventListener("fetch", (event) => {
+  event.respondWith(handleRequest(event));
+});
+
+async function handleRequest(event) {
+  const url = new URL(event.request.url);
+  const { request } = event;
+  const { headers } = request;
+
+  const referer = headers.get("Referer") || "";
+  const userAgent = headers.get("User-Agent");
+  const refHost = (() => {
+    try {
+      return new URL(referer).hostname;
+    } catch (e) {
+      return "";
+    }
+  })();
+  const uuid = getOrCreateUuid(headers);
+
+  event.waitUntil(logAnalyticsData(event, url, uuid, userAgent, referer));
+
+  const response = new Response(null, {
+    status: 204,
+    statusText: "No Content",
+  });
+
+  if (!headers.get("cookie")?.includes("uuid=")) {
+    response.headers.set(
+      "Set-Cookie",
+      `uuid=${uuid}; Expires=${new Date(Date.now() + 365 * 86400 * 30 * 1000).toUTCString()}; Path='/';`,
+    );
+  }
+
+  return response;
+}
+
+function shouldBlockRequest(refHost, userAgent, url) {
+  if (!refHost || !userAgent || !url.search.includes("ga=")) {
+    return true;
+  }
+  return false;
+}
+
+function getOrCreateUuid(headers) {
+  const cookie = headers.get("cookie") || "";
+  const uuidMatch = cookie.match(/uuid=([^;]+)/);
+  if (uuidMatch) {
+    return uuidMatch[1];
+  }
+  return crypto.randomUUID();
+}
+
+async function logAnalyticsData(event, url, uuid, userAgent, pageUrl) {
+  const { ANALYTICS_ENGINE } = globalThis;
+  const params = url.searchParams;
+
+  const dataPoint = {
+    blobs: [
+      pageUrl, // Page URL
+      userAgent, // User Agent
+      params.get("dt") || "", // Page Title
+      params.get("de") || "", // Document Encoding
+      params.get("dr") || "", // Document Referrer
+      params.get("ul") || "", // User Language
+      params.get("sd") || "", // Screen Colors
+      params.get("sr") || "", // Screen Resolution
+      params.get("vp") || "", // Viewport Size
+      uuid, // Client ID
+    ],
+    doubles: [
+      parseFloat(params.get("plt") || "0"), // Page Load Time
+      parseFloat(params.get("dns") || "0"), // DNS Time
+      parseFloat(params.get("pdt") || "0"), // Page Download Time
+      parseFloat(params.get("rrt") || "0"), // Redirect Response Time
+      parseFloat(params.get("tcp") || "0"), // TCP Connect Time
+      parseFloat(params.get("srt") || "0"), // Server Response Time
+      parseFloat(params.get("dit") || "0"), // DOM Interactive Time
+      parseFloat(params.get("clt") || "0"), // Content Loaded Time
+    ],
+    indexes: [
+      event.request.headers.get("CF-Connecting-IP") || "", // User IP
+    ],
+  };
+
+  ANALYTICS_ENGINE.writeDataPoint(dataPoint);
+}

workers/analytics/wrangler-analytics.toml

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+main="analytics_worker.js"
+name = "analytics"
+compatibility_date = "2024-12-20"
+
+routes = [
+    { pattern = "metrics.seemueller.io", custom_domain = true }
+]
+
+[dev]
+port = 3003
+
+[placement]
+mode = "smart"
+
+[[analytics_engine_datasets]]
+binding = "ANALYTICS_ENGINE"
+dataset = "global_analytics"