Init (#1)

backend/rate-limiter.ts

@@ -0,0 +1,75 @@
+// "limit" is bugged in Typescript, use "limiter-es6-compat" instead
+// See https://github.com/jhurliman/node-rate-limiter/issues/80
+import { RateLimiter } from "limiter-es6-compat";
+import { log } from "./log";
+
+class KumaRateLimiter {
+
+    errorMessage : string;
+    rateLimiter : RateLimiter;
+
+    /**
+     * @param {object} config Rate limiter configuration object
+     */
+    constructor(config) {
+        this.errorMessage = config.errorMessage;
+        this.rateLimiter = new RateLimiter(config);
+    }
+
+    /**
+     * Callback for pass
+     * @callback passCB
+     * @param {object} err Too many requests
+     */
+
+    /**
+     * Should the request be passed through
+     * @param {passCB} callback Callback function to call with decision
+     * @param {number} num Number of tokens to remove
+     * @returns {Promise<boolean>} Should the request be allowed?
+     */
+    async pass(callback, num = 1) {
+        const remainingRequests = await this.removeTokens(num);
+        log.info("rate-limit", "remaining requests: " + remainingRequests);
+        if (remainingRequests < 0) {
+            if (callback) {
+                callback({
+                    ok: false,
+                    msg: this.errorMessage,
+                });
+            }
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Remove a given number of tokens
+     * @param {number} num Number of tokens to remove
+     * @returns {Promise<number>} Number of remaining tokens
+     */
+    async removeTokens(num = 1) {
+        return await this.rateLimiter.removeTokens(num);
+    }
+}
+
+export const loginRateLimiter = new KumaRateLimiter({
+    tokensPerInterval: 20,
+    interval: "minute",
+    fireImmediately: true,
+    errorMessage: "Too frequently, try again later."
+});
+
+export const apiRateLimiter = new KumaRateLimiter({
+    tokensPerInterval: 60,
+    interval: "minute",
+    fireImmediately: true,
+    errorMessage: "Too frequently, try again later."
+});
+
+export const twoFaRateLimiter = new KumaRateLimiter({
+    tokensPerInterval: 30,
+    interval: "minute",
+    fireImmediately: true,
+    errorMessage: "Too frequently, try again later."
+});