1 files changed, 86 insertions, 0 deletions
diff --git a/packages/plugins/ratelimit-memory/src/index.ts b/packages/plugins/ratelimit-memory/src/index.ts
new file mode 100644
index 00000000..c47889d3
--- /dev/null
+++ b/packages/plugins/ratelimit-memory/src/index.ts
@@ -0,0 +1,86 @@
+import type {
+  RateLimitClient,
+  RateLimitConfig,
+  RateLimitResult,
+} from "@karakeep/shared/ratelimiting";
+import { PluginProvider } from "@karakeep/shared/plugins";
+
+interface RateLimitEntry {
+  count: number;
+  resetTime: number;
+}
+
+export class RateLimiter implements RateLimitClient {
+  private store = new Map<string, RateLimitEntry>();
+  private cleanupProbability: number;
+
+  constructor(cleanupProbability = 0.01) {
+    // Probability of cleanup on each check (default 1%)
+    this.cleanupProbability = cleanupProbability;
+  }
+
+  private cleanupExpiredEntries() {
+    const now = Date.now();
+    for (const [key, entry] of this.store.entries()) {
+      if (now > entry.resetTime) {
+        this.store.delete(key);
+      }
+    }
+  }
+
+  checkRateLimit(config: RateLimitConfig, key: string): RateLimitResult {
+    if (!key) {
+      return { allowed: true };
+    }
+
+    // Probabilistic cleanup
+    if (Math.random() < this.cleanupProbability) {
+      this.cleanupExpiredEntries();
+    }
+
+    const rateLimitKey = `${config.name}:${key}`;
+    const now = Date.now();
+
+    let entry = this.store.get(rateLimitKey);
+
+    if (!entry || now > entry.resetTime) {
+      entry = {
+        count: 1,
+        resetTime: now + config.windowMs,
+      };
+      this.store.set(rateLimitKey, entry);
+      return { allowed: true };
+    }
+
+    if (entry.count >= config.maxRequests) {
+      const resetInSeconds = Math.ceil((entry.resetTime - now) / 1000);
+      return {
+        allowed: false,
+        resetInSeconds,
+      };
+    }
+
+    entry.count++;
+    return { allowed: true };
+  }
+
+  reset(config: RateLimitConfig, key: string) {
+    const rateLimitKey = `${config.name}:${key}`;
+    this.store.delete(rateLimitKey);
+  }
+
+  clear() {
+    this.store.clear();
+  }
+}
+
+export class RateLimitProvider implements PluginProvider<RateLimitClient> {
+  private client: RateLimiter | null = null;
+
+  async getClient(): Promise<RateLimitClient | null> {
+    if (!this.client) {
+      this.client = new RateLimiter();
+    }
+    return this.client;
+  }
+}