rateLimiter.ts•3.02 kB
import { config } from '../config/index.js';
import { RateLimitError } from './errors.js';
import { logger } from './logger.js';
interface RateLimitEntry {
count: number;
resetTime: number;
}
/**
* Simple in-memory rate limiter using sliding window
*/
export class RateLimiter {
private requests = new Map<string, RateLimitEntry>();
private cleanupInterval: NodeJS.Timeout;
constructor(
private maxRequests: number = config.rateLimitRequests,
private windowMs: number = config.rateLimitWindow
) {
// Clean up expired entries every minute
this.cleanupInterval = setInterval(() => {
this.cleanup();
}, 60000);
}
/**
* Check if request is allowed for the given identifier
*/
checkLimit(identifier: string = 'default'): void {
if (!config.rateLimitEnabled) {
return;
}
const now = Date.now();
const entry = this.requests.get(identifier);
if (!entry) {
// First request for this identifier
this.requests.set(identifier, {
count: 1,
resetTime: now + this.windowMs
});
return;
}
if (now >= entry.resetTime) {
// Window has expired, reset
entry.count = 1;
entry.resetTime = now + this.windowMs;
return;
}
if (entry.count >= this.maxRequests) {
const resetIn = Math.ceil((entry.resetTime - now) / 1000);
logger.security(`Rate limit exceeded for ${identifier}`, {
count: entry.count,
limit: this.maxRequests,
resetIn
});
throw new RateLimitError(`Rate limit exceeded. Try again in ${resetIn} seconds.`);
}
entry.count++;
}
/**
* Get current usage for identifier
*/
getUsage(identifier: string = 'default'): { count: number; limit: number; resetTime: number } {
const entry = this.requests.get(identifier);
const now = Date.now();
if (!entry || now >= entry.resetTime) {
return {
count: 0,
limit: this.maxRequests,
resetTime: now + this.windowMs
};
}
return {
count: entry.count,
limit: this.maxRequests,
resetTime: entry.resetTime
};
}
/**
* Clean up expired entries
*/
private cleanup(): void {
const now = Date.now();
let cleaned = 0;
for (const [identifier, entry] of this.requests.entries()) {
if (now >= entry.resetTime) {
this.requests.delete(identifier);
cleaned++;
}
}
if (cleaned > 0) {
logger.debug(`Cleaned up ${cleaned} expired rate limit entries`);
}
}
/**
* Reset rate limit for identifier
*/
reset(identifier: string = 'default'): void {
this.requests.delete(identifier);
logger.debug(`Reset rate limit for ${identifier}`);
}
/**
* Destroy the rate limiter and clean up resources
*/
destroy(): void {
if (this.cleanupInterval) {
clearInterval(this.cleanupInterval);
}
this.requests.clear();
}
}
// Export singleton instance
export const rateLimiter = new RateLimiter();