website poc

apps/website/lib/rate-limit.ts

@@ -0,0 +1,89 @@
+import { kv } from '@vercel/kv';
+
+/**
+ * Rate limit configuration
+ */
+const RATE_LIMIT_WINDOW = 60 * 60 * 1000; // 1 hour in milliseconds
+const MAX_REQUESTS_PER_WINDOW = 5;
+
+/**
+ * Rate limit key prefix
+ */
+const RATE_LIMIT_PREFIX = 'ratelimit:signup:';
+
+/**
+ * Check if an IP address has exceeded rate limits
+ * @param identifier - IP address or unique identifier
+ * @returns Object with allowed status and retry information
+ */
+export async function checkRateLimit(identifier: string): Promise<{
+  allowed: boolean;
+  remaining: number;
+  resetAt: number;
+}> {
+  const key = `${RATE_LIMIT_PREFIX}${identifier}`;
+  const now = Date.now();
+  
+  try {
+    // Get current count
+    const count = await kv.get<number>(key) || 0;
+    
+    if (count >= MAX_REQUESTS_PER_WINDOW) {
+      // Get TTL to determine reset time
+      const ttl = await kv.ttl(key);
+      const resetAt = now + (ttl * 1000);
+      
+      return {
+        allowed: false,
+        remaining: 0,
+        resetAt,
+      };
+    }
+    
+    // Increment counter
+    const newCount = count + 1;
+    
+    if (count === 0) {
+      // First request - set with expiry
+      await kv.set(key, newCount, {
+        px: RATE_LIMIT_WINDOW,
+      });
+    } else {
+      // Subsequent request - increment without changing TTL
+      await kv.incr(key);
+    }
+    
+    // Calculate reset time
+    const ttl = await kv.ttl(key);
+    const resetAt = now + (ttl * 1000);
+    
+    return {
+      allowed: true,
+      remaining: MAX_REQUESTS_PER_WINDOW - newCount,
+      resetAt,
+    };
+  } catch (error) {
+    // If rate limiting fails, allow the request
+    console.error('Rate limit check failed:', error);
+    return {
+      allowed: true,
+      remaining: MAX_REQUESTS_PER_WINDOW,
+      resetAt: now + RATE_LIMIT_WINDOW,
+    };
+  }
+}
+
+/**
+ * Get client IP from request headers
+ */
+export function getClientIp(request: Request): string {
+  // Try various headers that might contain the IP
+  const headers = request.headers;
+  
+  return (
+    headers.get('x-forwarded-for')?.split(',')[0]?.trim() ||
+    headers.get('x-real-ip') ||
+    headers.get('cf-connecting-ip') || // Cloudflare
+    'unknown'
+  );
+}