rate limit and auth checks

lib/rate-limit.ts

@@ -0,0 +1,96 @@
+import { NextRequest, NextResponse } from "next/server";
+
+interface RateLimitEntry {
+  count: number;
+  resetAt: number;
+}
+
+const store = new Map<string, RateLimitEntry>();
+
+setInterval(() => {
+  const now = Date.now();
+  for (const [key, entry] of store) {
+    if (entry.resetAt < now) {
+      store.delete(key);
+    }
+  }
+}, 60000);
+
+export interface RateLimitConfig {
+  limit: number;
+  windowMs: number;
+}
+
+const DEFAULT_CONFIG: RateLimitConfig = {
+  limit: 60,
+  windowMs: 60 * 1000,
+};
+
+function getClientIp(request: NextRequest): string {
+  const xff = request.headers.get("x-forwarded-for");
+  if (xff) {
+    return xff.split(",")[0].trim();
+  }
+  const realIp = request.headers.get("x-real-ip");
+  if (realIp) {
+    return realIp;
+  }
+  return "unknown";
+}
+
+export function rateLimit(
+  request: NextRequest,
+  identifier?: string,
+  config: Partial<RateLimitConfig> = {}
+): { success: boolean; remaining: number; resetAt: number } {
+  const { limit, windowMs } = { ...DEFAULT_CONFIG, ...config };
+  const ip = getClientIp(request);
+  const key = identifier ? `${ip}:${identifier}` : ip;
+  const now = Date.now();
+
+  let entry = store.get(key);
+
+  if (!entry || entry.resetAt < now) {
+    entry = { count: 0, resetAt: now + windowMs };
+    store.set(key, entry);
+  }
+
+  entry.count++;
+
+  return {
+    success: entry.count <= limit,
+    remaining: Math.max(0, limit - entry.count),
+    resetAt: entry.resetAt,
+  };
+}
+
+export function withRateLimit(
+  handler: (request: NextRequest, context: any) => Promise<NextResponse>,
+  config: Partial<RateLimitConfig> & { identifier?: string } = {}
+) {
+  return async (request: NextRequest, context: any): Promise<NextResponse> => {
+    const { identifier, ...rateLimitConfig } = config;
+    const result = rateLimit(request, identifier, rateLimitConfig);
+
+    if (!result.success) {
+      return new NextResponse("Too Many Requests", {
+        status: 429,
+        headers: {
+          "Retry-After": Math.ceil((result.resetAt - Date.now()) / 1000).toString(),
+          "X-RateLimit-Limit": (rateLimitConfig.limit || DEFAULT_CONFIG.limit).toString(),
+          "X-RateLimit-Remaining": "0",
+          "X-RateLimit-Reset": result.resetAt.toString(),
+        },
+      });
+    }
+
+    const response = await handler(request, context);
+
+    response.headers.set("X-RateLimit-Limit", (rateLimitConfig.limit || DEFAULT_CONFIG.limit).toString());
+    response.headers.set("X-RateLimit-Remaining", result.remaining.toString());
+    response.headers.set("X-RateLimit-Reset", result.resetAt.toString());
+
+    return response;
+  };
+}
+