feat: add support for turnstile on signup

8 files changed, 165 insertions, 0 deletions

diff --git a/apps/web/components/signup/SignUpForm.tsx b/apps/web/components/signup/SignUpForm.tsx
index a1e8dadf..bd4a1cf2 100644
--- a/apps/web/components/signup/SignUpForm.tsx
+++ b/apps/web/components/signup/SignUpForm.tsx
@@ -25,6 +25,7 @@ import { Input } from "@/components/ui/input";
 import { useClientConfig } from "@/lib/clientConfig";
 import { api } from "@/lib/trpc";
 import { zodResolver } from "@hookform/resolvers/zod";
+import { Turnstile } from "@marsidev/react-turnstile";
 import { TRPCClientError } from "@trpc/client";
 import { AlertCircle, UserX } from "lucide-react";
 import { signIn } from "next-auth/react";
@@ -43,11 +44,13 @@ export default function SignUpForm() {
       name: "",
       password: "",
       confirmPassword: "",
+      turnstileToken: "",
     },
   });
   const [errorMessage, setErrorMessage] = useState("");
   const router = useRouter();
   const clientConfig = useClientConfig();
+  const turnstileSiteKey = clientConfig.turnstile?.siteKey;
 
   const createUserMutation = api.users.create.useMutation();
 
@@ -97,6 +100,14 @@ export default function SignUpForm() {
         <Form {...form}>
           <form
             onSubmit={form.handleSubmit(async (value) => {
+              if (turnstileSiteKey && !value.turnstileToken) {
+                form.setError("turnstileToken", {
+                  type: "manual",
+                  message: "Please complete the verification challenge",
+                });
+                return;
+              }
+              form.clearErrors("turnstileToken");
               try {
                 await createUserMutation.mutateAsync(value);
               } catch (e) {
@@ -205,6 +216,37 @@ export default function SignUpForm() {
               )}
             />
 
+            {turnstileSiteKey && (
+              <FormField
+                control={form.control}
+                name="turnstileToken"
+                render={({ field }) => (
+                  <FormItem>
+                    <FormLabel>Verification</FormLabel>
+                    <FormControl>
+                      <Turnstile
+                        siteKey={turnstileSiteKey}
+                        onSuccess={(token) => {
+                          field.onChange(token);
+                          form.clearErrors("turnstileToken");
+                        }}
+                        onExpire={() => field.onChange("")}
+                        onError={() => {
+                          field.onChange("");
+                          form.setError("turnstileToken", {
+                            type: "manual",
+                            message:
+                              "Verification failed, please reload the challenge",
+                          });
+                        }}
+                      />
+                    </FormControl>
+                    <FormMessage />
+                  </FormItem>
+                )}
+              />
+            )}
+
             <ActionButton
               type="submit"
               loading={
diff --git a/apps/web/lib/clientConfig.tsx b/apps/web/lib/clientConfig.tsx
index 03089e49..9331a7af 100644
--- a/apps/web/lib/clientConfig.tsx
+++ b/apps/web/lib/clientConfig.tsx
@@ -10,6 +10,7 @@ export const ClientConfigCtx = createContext<ClientConfig>({
     disableSignups: false,
     disablePasswordAuth: false,
   },
+  turnstile: null,
   inference: {
     isConfigured: false,
     inferredTagLang: "english",
diff --git a/apps/web/package.json b/apps/web/package.json
index 67ce2560..0c53490d 100644
--- a/apps/web/package.json
+++ b/apps/web/package.json
@@ -32,6 +32,7 @@
     "@lexical/plain-text": "^0.20.2",
     "@lexical/react": "^0.20.2",
     "@lexical/rich-text": "^0.20.2",
+    "@marsidev/react-turnstile": "^1.3.1",
     "@radix-ui/react-collapsible": "^1.1.11",
     "@radix-ui/react-dialog": "^1.1.14",
     "@radix-ui/react-dropdown-menu": "^2.1.15",
diff --git a/packages/shared/config.ts b/packages/shared/config.ts
index 634f083b..60beae1e 100644
--- a/packages/shared/config.ts
+++ b/packages/shared/config.ts
@@ -54,6 +54,8 @@ const allEnv = z.object({
   OAUTH_TIMEOUT: z.coerce.number().optional().default(3500),
   OAUTH_SCOPE: z.string().default("openid email profile"),
   OAUTH_PROVIDER_NAME: z.string().default("Custom Provider"),
+  TURNSTILE_SITE_KEY: z.string().optional(),
+  TURNSTILE_SECRET_KEY: z.string().optional(),
   OPENAI_API_KEY: z.string().optional(),
   OPENAI_BASE_URL: z.string().url().optional(),
   OLLAMA_BASE_URL: z.string().url().optional(),
@@ -237,6 +239,11 @@ const serverConfigSchema = allEnv.transform((val, ctx) => {
         name: val.OAUTH_PROVIDER_NAME,
         timeout: val.OAUTH_TIMEOUT,
       },
+      turnstile: {
+        enabled: val.TURNSTILE_SITE_KEY !== undefined,
+        siteKey: val.TURNSTILE_SITE_KEY,
+        secretKey: val.TURNSTILE_SECRET_KEY,
+      },
     },
     email: {
       smtp: val.SMTP_HOST
@@ -401,6 +408,15 @@ const serverConfigSchema = allEnv.transform((val, ctx) => {
     });
     return z.NEVER;
   }
+  if (obj.auth.turnstile.enabled && !obj.auth.turnstile.secretKey) {
+    ctx.addIssue({
+      code: z.ZodIssueCode.custom,
+      message:
+        "TURNSTILE_SECRET_KEY is required when TURNSTILE_SITE_KEY is set",
+      fatal: true,
+    });
+    return z.NEVER;
+  }
   return obj;
 });
 
@@ -416,6 +432,12 @@ export const clientConfig = {
     disableSignups: serverConfig.auth.disableSignups,
     disablePasswordAuth: serverConfig.auth.disablePasswordAuth,
   },
+  turnstile:
+    serverConfig.auth.turnstile.enabled && serverConfig.auth.turnstile.siteKey
+      ? {
+          siteKey: serverConfig.auth.turnstile.siteKey,
+        }
+      : null,
   inference: {
     isConfigured: serverConfig.inference.isConfigured,
     inferredTagLang: serverConfig.inference.inferredTagLang,
diff --git a/packages/shared/types/users.ts b/packages/shared/types/users.ts
index 2fad4f83..9f020d52 100644
--- a/packages/shared/types/users.ts
+++ b/packages/shared/types/users.ts
@@ -11,6 +11,7 @@ export const zSignUpSchema = z
     email: z.string().email(),
     password: z.string().min(PASSWORD_MIN_LENGTH).max(PASSWORD_MAX_LENGTH),
     confirmPassword: z.string(),
+    turnstileToken: z.string().optional(),
   })
   .refine((data) => data.password === data.confirmPassword, {
     message: "Passwords don't match",
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,
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index d22e69d0..adc2495f 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -537,6 +537,9 @@ importers:
       '@lexical/rich-text':
         specifier: ^0.20.2
         version: 0.20.2
+      '@marsidev/react-turnstile':
+        specifier: ^1.3.1
+        version: 1.3.1(react-dom@19.1.0(react@19.1.0))(react@19.1.0)
       '@radix-ui/react-collapsible':
         specifier: ^1.1.11
         version: 1.1.11(@types/react-dom@19.1.6(@types/react@19.1.8))(@types/react@19.1.8)(react-dom@19.1.0(react@19.1.0))(react@19.1.0)
@@ -3935,6 +3938,12 @@ packages:
     peerDependencies:
       yjs: '>=13.5.22'
 
+  '@marsidev/react-turnstile@1.3.1':
+    resolution: {integrity: sha512-h2THG/75k4Y049hgjSGPIcajxXnh+IZAiXVbryQyVmagkboN7pJtBgR16g8akjwUBSfRrg6jw6KvPDjscQflog==}
+    peerDependencies:
+      react: ^17.0.2 || ^18.0.0 || ^19.0
+      react-dom: ^17.0.2 || ^18.0.0 || ^19.0
+
   '@mdx-js/mdx@3.1.0':
     resolution: {integrity: sha512-/QxEhPAvGwbQmy1Px8F899L5Uc2KZ6JtXwlCgJmjSTBedwOZkByYcBG4GceIGPXRDsmfxhHazuS+hlOShRLeDw==}
 
@@ -18937,6 +18946,11 @@ snapshots:
       lexical: 0.20.2
       yjs: 13.6.27
 
+  '@marsidev/react-turnstile@1.3.1(react-dom@19.1.0(react@19.1.0))(react@19.1.0)':
+    dependencies:
+      react: 19.1.0
+      react-dom: 19.1.0(react@19.1.0)
+
   '@mdx-js/mdx@3.1.0(acorn@8.15.0)':
     dependencies:
       '@types/estree': 1.0.8