You will learn how to set expiration times on your Redis keys. This is useful for many situations, such as caching data, managing session lifetimes, or any scenario where you want data to expire automatically after a certain period. We will learn how to set expiration times on keys and check the remaining time-to-live (TTL) for a key.

Here's a quick preview of what you will be doing:

To set a key with an expiration time, you can use the set command with the EX option:

The above code snippet shows how to set a key (session:12345) with a value (data) that expires after 2 seconds.

To check the remaining time-to-live (TTL) for a key, you can use the ttl command with the key name as the parameter.

After waiting for the expiration time, you can verify that the key no longer exists. This code waits 3 seconds and then attempts to get the value of the key, which should return null because the key has expired.