B2B-88: add starter kit structure and elements

packages/features/auth/src/captcha/server/index.ts

@@ -0,0 +1 @@
+export * from './verify-captcha';

packages/features/auth/src/captcha/server/verify-captcha.tsx

@@ -0,0 +1,39 @@
+import 'server-only';
+
+const verifyEndpoint =
+  'https://challenges.cloudflare.com/turnstile/v0/siteverify';
+
+const CAPTCHA_SECRET_TOKEN = process.env.CAPTCHA_SECRET_TOKEN;
+
+/**
+ * @name verifyCaptchaToken
+ * @description Verify the CAPTCHA token with the CAPTCHA service
+ * @param token - The CAPTCHA token to verify
+ */
+export async function verifyCaptchaToken(token: string) {
+  if (!CAPTCHA_SECRET_TOKEN) {
+    throw new Error('CAPTCHA_SECRET_TOKEN is not set');
+  }
+
+  const formData = new FormData();
+
+  formData.append('secret', CAPTCHA_SECRET_TOKEN);
+  formData.append('response', token);
+
+  const res = await fetch(verifyEndpoint, {
+    method: 'POST',
+    body: formData,
+  });
+
+  if (!res.ok) {
+    console.error(`Captcha failed:`, res.statusText);
+
+    throw new Error('Failed to verify CAPTCHA token');
+  }
+
+  const data = await res.json();
+
+  if (!data.success) {
+    throw new Error('Invalid CAPTCHA token');
+  }
+}