Managing Key Expiration with Redis and C++

#include <iostream>
#include <hiredis/hiredis.h>
#include <chrono>
#include <thread>

int main() {
    // Connect to the Redis server
    redisContext* context = redisConnect("127.0.0.1", 6379);
    if (context == nullptr || context->err) {
        if (context) {
            std::cerr << "Connection error: " << context->errstr << std::endl;
        } else {
            std::cerr << "Connection error: can't allocate Redis context" << std::endl;
        }
        return 1;
    }

    // Set a key with an expiration time of 2 seconds
    const char* key = "session:12345";
    redisReply* reply = (redisReply*)redisCommand(context, "SET %s %s EX %d", key, "data", 2);
    freeReplyObject(reply);

    // Check the time-to-live (TTL) for the key
    reply = (redisReply*)redisCommand(context, "TTL %s", key);
    if (reply->type == REDIS_REPLY_INTEGER) {
        std::cout << "Time-to-live for session key: " << reply->integer << " seconds." << std::endl;
    }
    freeReplyObject(reply);
    // Get the key before expiration
    reply = (redisReply*)redisCommand(context, "GET %s", key);
    if (reply->type != REDIS_REPLY_NIL) {
        std::cout << reply->str << std::endl;  
    } else {
        std::cout << "Unexpected return value." << std::endl;
    }
    // Sleep for 3 seconds, longer than expiration to check the key status
    std::this_thread::sleep_for(std::chrono::seconds(3));

    // Try to get the key after expiration
    reply = (redisReply*)redisCommand(context, "GET %s", key);
    if (reply->type == REDIS_REPLY_NIL) {
        std::cout << "Value: None" << std::endl;  // The key no longer exists
    } else {
        std::cout << "Unexpected return value." << std::endl;
    }
    freeReplyObject(reply);

    // Free the context
    redisFree(context);

    return 0;
}

//Output
// Time-to-live for session key: 2 seconds.
// data
// Value: None

redisReply* reply = (redisReply*)redisCommand(context, "SET %s %s", key, "data");
freeReplyObject(reply);

reply = (redisReply*)redisCommand(context, "EXPIRE %s %d", key, 2);
freeReplyObject(reply);