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. This is a fundamental part of our project that will set the stage for more advanced features in later units. Each unit will focus on a specific aspect of the project, allowing you to build a complete system step by step.

Let's take a quick look at what you'll be building in this unit. We will focus on two key operations for managing user data:

1. Adding user data with an expiration time: This will ensure that user data is stored for a limited period and automatically deleted afterward.
2. Retrieving user data: This operation will help us fetch the user data we previously stored.

Here’s a quick example of how we will structure these operations:

JavaScript
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1import { createClient } from 'redis';
2const client = createClient();
3
4client.on('error', (err) => {
5  console.error('Error connecting to Redis', err);
6});
7
8await client.connect();
9
10const data = {
11  email: 'user1@example.com'
12};
13
14// Add user data with expiration
15await client.set('user:1', JSON.stringify(data), {
16  EX: 86400 // Expires in 1 day (86400 seconds)
17});
18
19// Retrieve user data
20const retrievedData = await client.get('user:1');
21const parsedData = JSON.parse(retrievedData);
22console.log(parsedData); // Output: { email: 'user1@example.com' }
23
24await client.disconnect();

Notice how in JavaScript, we use import to bring in the necessary module. We handle any connection errors using an event listener. We use JSON.stringify to convert data to a JSON string before storing it and then JSON.parse to convert it back to an object when retrieving it.

We also specify the expiration time directly in seconds (e.g., 86400 for one day) using the EX option in the set command.

Now that you have a clear idea of what you'll be building, let's start the practice section and implement this logic. This will solidify your understanding and prepare you for more complex tasks in the upcoming units.