feat: add support for turnstile on signup

2 files changed, 84 insertions, 0 deletions

diff --git a/packages/trpc/lib/turnstile.ts b/packages/trpc/lib/turnstile.ts
new file mode 100644
index 00000000..3ba25f05
--- /dev/null
+++ b/packages/trpc/lib/turnstile.ts
@@ -0,0 +1,71 @@
+import { z } from "zod";
+
+import serverConfig from "@karakeep/shared/config";
+import logger from "@karakeep/shared/logger";
+
+const TurnstileVerifyResponseSchema = z.object({
+  success: z.boolean(),
+  challenge_ts: z.string().optional(),
+  hostname: z.string().optional(),
+  "error-codes": z.array(z.string()).optional(),
+});
+
+export async function verifyTurnstileToken(
+  token: string,
+  remoteIp?: string | null,
+) {
+  if (!serverConfig.auth.turnstile.enabled) {
+    return { success: true };
+  }
+
+  if (!token) {
+    return { success: false, "error-codes": ["missing-input-response"] };
+  }
+
+  const body = new URLSearchParams();
+  body.append("secret", serverConfig.auth.turnstile.secretKey!);
+  body.append("response", token);
+  if (remoteIp) {
+    body.append("remoteip", remoteIp);
+  }
+
+  try {
+    const response = await fetch(
+      "https://challenges.cloudflare.com/turnstile/v0/siteverify",
+      {
+        method: "POST",
+        body,
+      },
+    );
+
+    if (!response.ok) {
+      logger.warn(
+        `[Turnstile] Verification request failed with status ${response.status}`,
+      );
+      return { success: false, "error-codes": ["request-not-ok"] };
+    }
+
+    const json = await response.json();
+    const parseResult = TurnstileVerifyResponseSchema.safeParse(json);
+
+    if (!parseResult.success) {
+      logger.warn("[Turnstile] Invalid response format", {
+        error: parseResult.error,
+        remoteIp,
+      });
+      return { success: false, "error-codes": ["invalid-response"] };
+    }
+
+    const parsed = parseResult.data;
+    if (!parsed.success) {
+      logger.warn("[Turnstile] Verification failed", {
+        errorCodes: parsed["error-codes"],
+        remoteIp,
+      });
+    }
+    return parsed;
+  } catch (error) {
+    logger.warn("[Turnstile] Verification threw", { error, remoteIp });
+    return { success: false, "error-codes": ["internal-error"] };
+  }
+}
diff --git a/packages/trpc/routers/users.ts b/packages/trpc/routers/users.ts
index 5ce9c67e..d3bc06d9 100644
--- a/packages/trpc/routers/users.ts
+++ b/packages/trpc/routers/users.ts
@@ -18,6 +18,7 @@ import {
   publicProcedure,
   router,
 } from "../index";
+import { verifyTurnstileToken } from "../lib/turnstile";
 import { User } from "../models/users";
 
 export const usersAppRouter = router({
@@ -51,6 +52,18 @@ export const usersAppRouter = router({
           message: errorMessage,
         });
       }
+      if (serverConfig.auth.turnstile.enabled) {
+        const result = await verifyTurnstileToken(
+          input.turnstileToken ?? "",
+          ctx.req.ip,
+        );
+        if (!result.success) {
+          throw new TRPCError({
+            code: "BAD_REQUEST",
+            message: "Turnstile verification failed",
+          });
+        }
+      }
       const user = await User.create(ctx, input);
       return {
         id: user.id,