import type {
RateLimiter,
RateLimitConfig,
RateLimitStrategy,
} from "./types.js";
import { FixedWindowRateLimiter } from "./strategies/fixed-window.js";
import { SlidingWindowRateLimiter } from "./strategies/sliding-window.js";
import { TokenBucketRateLimiter } from "./strategies/token-bucket.js";
import { LeakyBucketRateLimiter } from "./strategies/leaky-bucket.js";
import {
AfterNRateLimiter,
RandomRateLimiter,
AlwaysRateLimiter,
NoOpRateLimiter,
} from "./strategies/simple.js";
/**
* Factory to create rate limiters based on strategy name
*/
export function createRateLimiter(config: RateLimitConfig): RateLimiter {
if (!config.enabled) {
return new NoOpRateLimiter();
}
switch (config.strategy) {
case "none":
return new NoOpRateLimiter();
case "fixed-window":
return new FixedWindowRateLimiter(config);
case "sliding-window":
return new SlidingWindowRateLimiter(config);
case "token-bucket":
return new TokenBucketRateLimiter(config);
case "leaky-bucket":
return new LeakyBucketRateLimiter(config);
case "after-n":
return new AfterNRateLimiter(config);
case "random":
return new RandomRateLimiter(config);
case "always":
return new AlwaysRateLimiter(config);
default:
console.warn(
`Unknown rate limit strategy: ${config.strategy}, falling back to fixed-window`,
);
return new FixedWindowRateLimiter(config);
}
}
/**
* Get human-readable description of a strategy
*/
export function getStrategyDescription(strategy: RateLimitStrategy): string {
const descriptions: Record<RateLimitStrategy, string> = {
none: "Disabled - no rate limiting",
"fixed-window": "Fixed Window - N requests per time window",
"sliding-window": "Sliding Window - N requests in rolling window",
"token-bucket": "Token Bucket - burst-friendly with steady refill",
"leaky-bucket": "Leaky Bucket - smooth constant rate output",
"after-n": "After N - fail after N total requests",
random: "Random - fail with probability P",
always: "Always - reject all requests",
};
return descriptions[strategy] || strategy;
}
/**
* Get all available strategies
*/
export function getAvailableStrategies(): RateLimitStrategy[] {
return [
"none",
"fixed-window",
"sliding-window",
"token-bucket",
"leaky-bucket",
"after-n",
"random",
"always",
];
}
