/**
* Rate Limiter for MCP Tools
*/
import { createChildLogger } from '../utils/logger.js';
import type { RateLimitConfig } from '../types.js';
const logger = createChildLogger('rate-limiter');
interface RateLimitEntry {
count: number;
resetAt: number;
}
export class RateLimiter {
private limits: Map<string, RateLimitEntry> = new Map();
private config: Record<string, RateLimitConfig>;
constructor(config: Record<string, RateLimitConfig>) {
this.config = config;
// Cleanup expired entries periodically
setInterval(() => this.cleanup(), 60000);
}
/**
* Check if a request is allowed
*/
check(category: string, identifier: string = 'default'): boolean {
const limitConfig = this.config[category];
if (!limitConfig) {
return true;
}
const key = `${category}:${identifier}`;
const now = Date.now();
const entry = this.limits.get(key);
if (!entry || now >= entry.resetAt) {
this.limits.set(key, {
count: 1,
resetAt: now + limitConfig.windowMs,
});
return true;
}
if (entry.count >= limitConfig.max) {
logger.warn({ category, identifier, count: entry.count }, 'Rate limit exceeded');
return false;
}
entry.count++;
return true;
}
/**
* Get remaining requests for a category
*/
getRemaining(category: string, identifier: string = 'default'): number {
const limitConfig = this.config[category];
if (!limitConfig) {
return Infinity;
}
const key = `${category}:${identifier}`;
const entry = this.limits.get(key);
const now = Date.now();
if (!entry || now >= entry.resetAt) {
return limitConfig.max;
}
return Math.max(0, limitConfig.max - entry.count);
}
/**
* Get time until reset in ms
*/
getResetTime(category: string, identifier: string = 'default'): number {
const key = `${category}:${identifier}`;
const entry = this.limits.get(key);
const now = Date.now();
if (!entry || now >= entry.resetAt) {
return 0;
}
return entry.resetAt - now;
}
/**
* Clean up expired entries
*/
private cleanup(): void {
const now = Date.now();
let cleaned = 0;
for (const [key, entry] of this.limits.entries()) {
if (now >= entry.resetAt) {
this.limits.delete(key);
cleaned++;
}
}
if (cleaned > 0) {
logger.debug({ cleaned }, 'Cleaned up rate limit entries');
}
}
}
/**
* Get rate limit category for a tool
*/
export function getToolCategory(toolName: string): string {
if (toolName.includes('swap') || toolName.includes('buy') || toolName.includes('sell')) {
return 'swaps';
}
if (toolName.includes('wallet') || toolName.includes('fund') || toolName.includes('consolidate')) {
return 'walletOps';
}
if (toolName.includes('campaign')) {
return 'campaigns';
}
return 'queries';
}
