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99_references/supabase-examples/edge-functions/supabase/functions/cloudflare-turnstile/README.md

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+# Cloudflare Turnstile
+
+Turnstile is Cloudflare's CAPTCHA alternative: https://developers.cloudflare.com/turnstile/get-started/
+
+## Watch the Video Tutorial
+
+[![video tutorial](https://img.youtube.com/vi/OwW0znboh60/0.jpg)](https://www.youtube.com/watch?v=OwW0znboh60)
+
+## Setup
+
+- Follow these steps to set up a new site: https://developers.cloudflare.com/turnstile/get-started/
+- Add the Cloudflare Turnstile widget to your site: https://developers.cloudflare.com/turnstile/get-started/client-side-rendering/
+
+## Deploy the server-side validation Edge Functions
+
+- https://developers.cloudflare.com/turnstile/get-started/server-side-validation/
+
+```bash
+supabase functions deploy cloudflare-turnstile
+supabase secrets set CLOUDFLARE_TURNSTILE_SECRET_KEY=your_secret_key
+```
+
+## Invoke the function from your site
+
+```js
+const { data, error } = await supabase.functions.invoke('cloudflare-turnstile', {
+  body: { token },
+})
+```

99_references/supabase-examples/edge-functions/supabase/functions/cloudflare-turnstile/index.ts

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+// Follow this setup guide to integrate the Deno language server with your editor:
+// https://deno.land/manual/getting_started/setup_your_environment
+// This enables autocomplete, go to definition, etc.
+
+import { corsHeaders } from '../_shared/cors.ts'
+
+console.log(`Function "cloudflare-turnstile" up and running!`)
+
+function ips(req: Request) {
+  return req.headers.get('x-forwarded-for')?.split(/\s*,\s*/)
+}
+
+Deno.serve(async (req) => {
+  // This is needed if you're planning to invoke your function from a browser.
+  if (req.method === 'OPTIONS') {
+    return new Response('ok', { headers: corsHeaders })
+  }
+
+  try {
+    const { token } = await req.json()
+    if (!token) throw new Error('Missing token!')
+
+    const clientIps = ips(req) || ['']
+
+    // Validate the token by calling the
+    // "/siteverify" API endpoint.
+    const formData = new FormData()
+    formData.append('secret', Deno.env.get('CLOUDFLARE_TURNSTILE_SECRET_KEY') ?? '')
+    formData.append('response', token)
+    formData.append('remoteip', clientIps[0])
+
+    const url = 'https://challenges.cloudflare.com/turnstile/v0/siteverify'
+    const result = await fetch(url, {
+      body: formData,
+      method: 'POST',
+    })
+
+    const outcome = await result.json()
+    console.log(outcome)
+    if (outcome.success) {
+      return new Response(JSON.stringify(outcome), {
+        headers: { ...corsHeaders, 'Content-Type': 'application/json' },
+        status: 200,
+      })
+    }
+
+    throw new Error('Turnstile validation failed!')
+  } catch (error) {
+    return new Response(JSON.stringify({ error: error.message }), {
+      headers: { ...corsHeaders, 'Content-Type': 'application/json' },
+      status: 400,
+    })
+  }
+})
+
+// To invoke:
+// curl -i --location --request POST 'http://localhost:54321/functions/v1/cloudflare-turnstile' \
+//   --header 'Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJzdXBhYmFzZS1kZW1vIiwicm9sZSI6ImFub24iLCJleHAiOjE5ODM4MTI5OTZ9.CRXP1A7WOeoJeXxjNni43kdQwgnWNReilDMblYTn_I0' \
+//   --header 'Content-Type: application/json' \
+//   --data '{"token":"cf-turnstile-response"}'