fix: deliver GoatCounter visits through backend API

.env.example

@@ -13,3 +13,8 @@ VITE_REMOTE_SERVER_URL=http://localhost:4014
 
 # Controls the initial visibility of the Sample Data section.
 VITE_SHOW_SAMPLE_DATA=true
+
+# Optional Netlify Edge Function analytics. Set these in Netlify's Functions
+# scope for the deployment contexts to track. Never use a VITE_ prefix for tokens.
+GOATCOUNTER_SITE=
+GOATCOUNTER_API_TOKEN=

netlify/edge-functions/visits.ts

@@ -1,38 +1,73 @@
-// This file runs in the Deno runtime
+/* global Netlify */
+import type { Context } from '@netlify/edge-functions';
 
-// @ts-ignore
-// eslint-disable-next-line import/no-unresolved
-import { Context } from 'https://edge.netlify.com';
-
-// @ts-ignore
-const GOATCOUNTER_SITE = Deno.env.get('GOATCOUNTER_SITE');
-
-export default async (request: Request, context: Context) => {
-  if (!GOATCOUNTER_SITE) return;
-
-  const headers = { 'X-Forwarded-For': context.ip };
-  const url = new URL(GOATCOUNTER_SITE);
-  const { searchParams } = url;
-
-  url.pathname = '/count';
+function getReferrer(request: Request) {
+  const referrer = request.headers.get('Referer');
+  if (!referrer) return undefined;
+  try {
+    const url = new URL(referrer);
+    return `${url.protocol}//${url.host}${url.pathname}`;
+  } catch {
+    return undefined;
+  }
+}
 
-  const requestUrl = new URL(request.url);
-  searchParams.set('p', `${requestUrl.host}${requestUrl.pathname}`);
-  searchParams.set('t', 'VolView');
+async function countVisit(
+  request: Request,
+  ip: string,
+  site: string,
+  token: string
+) {
+  try {
+    const requestUrl = new URL(request.url);
+    const response = await fetch(new URL('/api/v0/count', site), {
+      method: 'POST',
+      headers: {
+        Authorization: `Bearer ${token}`,
+        'Content-Type': 'application/json',
+      },
+      redirect: 'error',
+      signal: AbortSignal.timeout(10_000),
+      body: JSON.stringify({
+        hits: [
+          {
+            path: `${requestUrl.host}${requestUrl.pathname}`,
+            title: 'VolView',
+            ref: getReferrer(request),
+            user_agent: request.headers.get('User-Agent') || 'Unknown',
+            ip,
+          },
+        ],
+      }),
+    });
+    await response.body?.cancel();
 
-  if (request.headers.has('Referer')) {
-    searchParams.set(
-      'r',
-      encodeURIComponent(request.headers.get('Referer') ?? '')
+    if (response.status !== 202) {
+      console.error(`GoatCounter request rejected (HTTP ${response.status}).`);
+    } else if (response.headers.has('X-Goatcounter-Filter')) {
+      console.info('GoatCounter visit filtered (HTTP 202).');
+    }
+  } catch {
+    // Errors and response bodies may contain visitor data or credentials.
+    console.error(
+      'GoatCounter request failed. Check configuration and network.'
     );
   }
+}
+
+export default (request: Request, context: Context) => {
+  if (request.method !== 'GET') return;
+
+  const site = Netlify.env.get('GOATCOUNTER_SITE');
+  if (!site) return;
 
-  if (request.headers.has('User-Agent')) {
-    headers['User-Agent'] = request.headers.get('User-Agent') ?? 'Unknown';
+  const token = Netlify.env.get('GOATCOUNTER_API_TOKEN');
+  if (!token) {
+    console.warn('GoatCounter disabled: GOATCOUNTER_API_TOKEN is not set.');
+    return;
   }
 
-  // don't block the request
-  fetch(url.toString(), { headers });
+  context.waitUntil(countVisit(request, context.ip, site, token));
 };
 
 export const config = { path: '/' };