import redis.asyncio as redis
from typing import Optional

class RedisCache:
    def __init__(self, host: str, port: int, db: int):
        self.client = redis.Redis(host=host, port=port, db=db, decode_responses=True)

    async def get(self, key: str) -> Optional[str]:
        return await self.client.get(key)

    async def set(self, key: str, value: str, ttl: int):
        await self.client.setex(key, ttl, value)

    async def close(self):
        await self.client.close()