Rate Limiter Algorithms

Library that provides different algorithms to perform rate limiting.

Example with Node.js

import { createServer } from "node:http";
import { RateLimiter } from "rate-limiter-algorithms";

const limiter = new RateLimiter({
    algorithm: "token-bucket",
    limit: 5,
    windowMs: 5000,
});

const server = createServer(async (req, res) => {
    const ip = req.socket.remoteAddress || "any unique key";

    try {
        const { isAllowed, clientData } = await limiter.consume(ip);

        // set rate limiting headers
        const headers = limiter.getHeaders(clientData);
        for (const header of headers) {
            res.setHeader(header[0], header[1]);
        }

        if (!isAllowed) {
            res.writeHead(429, "Too many requests");
            res.end("Failure");
            return;
        }
        res.end("Success");
    } catch (error) {
        console.error("Error in rate limiting:", error);
    }
});

server.listen(3000, "127.0.0.1", () => {
    console.log("Listening on 127.0.0.1:3000");
});

Config

| Option | Type | Explanation | | ----------- | -------- | ----------------------------------------------------------------------------------------------- | | algorithm | string | Values: token-bucket, fixed-window-counter, sliding-window-logs, sliding-window-counter | | windowMs | number | Duration of time in milliseconds when algorithm updates its counter. | | limit | number | Maximum amount of points that client can consume | | store | Store | Store which contains clients data based on chosen algorithm. Defaults to Memory Store |

Date Stores

Memory Store

Default in-memory option. Example:

import { RateLimiter, MemoryStore } from "rate-limiter-algorithms";

const limiter = new RateLimiter({
    algorithm: "token-bucket",
    limit: 5,
    windowMs: 5000,
    store: new MemoryStore(),
});

Redis Store

Uses rawCall function to send raw commands to Redis. Example for node-redis :

import { RateLimiter, RedisStore } from "rate-limiter-algorithms";
import { createClient } from "redis";

const client = createClient();
client.connect();

const limiter = new RateLimiter({
    algorithm: "token-bucket",
    limit: 5,
    windowMs: 5000,
    store: new RedisStore({
        prefix: "rla:", // it's default prefix
        rawCall: (...args: string[]) => client.sendCommand(args),
    }),,
});

Raw command list:

| Library | Function | | --------------------------------------------------- | ----------------------------------------------------------------------- | | node-redis | (...args: string[]) => client.sendCommand(args) | | ioredis | (command: string, ...args: string[]) => client.call(command, ...args) |

License

All code and documentation are (c) 2024 Eugene Shumilin and released under the MIT License