import type { Request, Response, NextFunction } from "express";
interface CacheOptions {
    duration: number;
    keyGenerator?: (req: Request) => string;
    cacheNullValues?: boolean;
    cacheErrorResponses?: boolean;
    maxSize?: number;
    staleWhileRevalidate?: boolean;
}
declare class MemoryCache {
    private cache;
    private logger;
    private maxSize;
    private cleanupInterval;
    constructor(options?: {
        maxSize?: number;
        cleanupInterval?: number;
    });
    set(key: string, value: any, duration: number): void;
    get(key: string): any | undefined;
    delete(key: string): void;
    clear(): void;
    size(): number;
    keys(): string[];
    has(key: string): boolean;
    private evictLeastRecentlyUsed;
    startCleanupInterval(intervalMs: number): void;
    stopCleanupInterval(): void;
}
declare const memoryCache: MemoryCache;
export declare function cacheMiddleware(options: CacheOptions): (req: Request, res: Response, next: NextFunction) => void;
export { memoryCache };