Welcome to the first step in building our Redis-based backend system. In this unit, we will focus on how to manage user data with expiration using Redis in PHP. This is a fundamental part of our project that will set the stage for more advanced features in later units.
In this unit, we will implement two primary operations for managing user data using PHP:
Here is a PHP code example to help illustrate these operations:
In this example, set is used to store user data, and expire is used to set the expiration time, which is specified as 24 * 60 * 60 to represent a duration of one day in seconds. The get method is used to retrieve the stored data.
The expire method is called separately from set because, by default, set does not automatically associate an expiration time with the key. If you want to set a key with an expiration in one step, you can use setex, which both stores the value and sets an expiration time:
This eliminates the need for a separate expire call and ensures atomicity.
Redis provides a built-in mechanism to automatically delete keys when their expiration time is reached. This is particularly useful for managing temporary data, such as session tokens, one-time authentication codes, or cache entries, without the need for manual cleanup. When a key expires, Redis removes it from memory, making it an efficient solution for handling time-sensitive user data.
There are two strategies for key expiration:
This foundational knowledge will prepare you for more complex tasks in upcoming lessons. Let's move on to practice implementing this logic to reinforce your understanding.