add login rate limiter

server/rate-limiter.js

@@ -0,0 +1,39 @@
+const { RateLimiter } = require("limiter");
+const { debug } = require("../src/util");
+
+class KumaRateLimiter {
+    constructor(config) {
+        this.errorMessage = config.errorMessage;
+        this.rateLimiter = new RateLimiter(config);
+    }
+
+    async pass(callback, num = 1) {
+        const remainingRequests = await this.removeTokens(num);
+        debug("Rate Limit (remainingRequests):" + remainingRequests);
+        if (remainingRequests < 0) {
+            if (callback) {
+                callback({
+                    ok: false,
+                    msg: this.errorMessage,
+                });
+            }
+            return false;
+        }
+        return true;
+    }
+
+    async removeTokens(num = 1) {
+        return await this.rateLimiter.removeTokens(num);
+    }
+}
+
+const loginRateLimiter = new KumaRateLimiter({
+    tokensPerInterval: 20,
+    interval: "minute",
+    fireImmediately: true,
+    errorMessage: "Too frequently, try again later."
+});
+
+module.exports = {
+    loginRateLimiter
+};