import { RateLimitError } from './errors.js';
interface RateLimiterOptions {
maxRequests: number;
windowMs: number;
keyGenerator?: (context: any) => string;
}
interface RequestRecord {
timestamp: number;
count: number;
}
export class ImprovedRateLimiter {
private requests = new Map<string, RequestRecord[]>();
private maxRequests: number;
private windowMs: number;
private keyGenerator: (context: any) => string;
private cleanupInterval: NodeJS.Timeout;
constructor(options: RateLimiterOptions) {
this.maxRequests = options.maxRequests;
this.windowMs = options.windowMs;
this.keyGenerator = options.keyGenerator || (() => 'global');
// Cleanup old entries every minute
this.cleanupInterval = setInterval(() => this.cleanup(), 60000);
}
async acquire(context?: any): Promise<void> {
const key = this.keyGenerator(context);
const now = Date.now();
// Get or create request records for this key
if (!this.requests.has(key)) {
this.requests.set(key, []);
}
const records = this.requests.get(key)!;
// Remove expired records
const validRecords = records.filter(
record => now - record.timestamp < this.windowMs
);
// Check if we're at the limit
const requestCount = validRecords.reduce((sum, record) => sum + record.count, 0);
if (requestCount >= this.maxRequests) {
// Calculate wait time until the oldest request expires
const oldestRecord = validRecords[0];
const waitTime = oldestRecord.timestamp + this.windowMs - now;
if (waitTime > 0) {
throw new RateLimitError(
`Rate limit exceeded. Please retry after ${Math.ceil(waitTime / 1000)} seconds.`
);
}
}
// Add current request
validRecords.push({ timestamp: now, count: 1 });
this.requests.set(key, validRecords);
}
private cleanup(): void {
const now = Date.now();
// Remove expired entries to prevent memory leaks
for (const [key, records] of this.requests.entries()) {
const validRecords = records.filter(
record => now - record.timestamp < this.windowMs
);
if (validRecords.length === 0) {
this.requests.delete(key);
} else {
this.requests.set(key, validRecords);
}
}
}
destroy(): void {
if (this.cleanupInterval) {
clearInterval(this.cleanupInterval);
}
this.requests.clear();
}
}
// Rate limiter instances
export const airtableRateLimiter = new ImprovedRateLimiter({
maxRequests: 5,
windowMs: 1000,
keyGenerator: (context) => context?.baseId || 'global',
});
export const clientRateLimiter = new ImprovedRateLimiter({
maxRequests: 100,
windowMs: 60000, // 1 minute
keyGenerator: (context) => context?.clientId || context?.ip || 'anonymous',
});
// Cleanup on process exit
process.on('exit', () => {
airtableRateLimiter.destroy();
clientRateLimiter.destroy();
});
