How to Use Redis as a Cache in Python

import json
import time
import redis


class RedisCache:
    def __init__(self, host="localhost", port=6379, db=0, default_ttl=60):
        self.client = redis.Redis(host=host, port=port, db=db, decode_responses=True)
        self.default_ttl = default_ttl

    def set(self, key, value, ttl=None):
        """Store a value with optional TTL (seconds)."""
        ttl = ttl or self.default_ttl
        data = json.dumps(value)
        self.client.setex(key, ttl, data)

    def get(self, key):
        """Retrieve a value, returning None if missing or expired."""
        data = self.client.get(key)
        if data is None:
            return None
        return json.loads(data)

    def delete(self, key):
        """Remove a key from cache."""
        self.client.delete(key)

    def exists(self, key):
        """Check if a key exists."""
        return self.client.exists(key) > 0


if __name__ == "__main__":
    cache = RedisCache(default_ttl=5)

    # Store and retrieve a simple value
    cache.set("greeting", {"message": "Hello world", "timestamp": time.time()})
    result = cache.get("greeting")
    print(f"Cached data: {result}")

    # Verify existence and quick cleanup
    print(f"Exists before delete: {cache.exists('greeting')}")
    cache.delete("greeting")
    print(f"Exists after delete: {cache.exists('greeting')}")