Using Redis as a Simple Database for Node.js Express.js Web Apps

If you’re building a web application using Node.js and Express.js, then you’ll need a database to store and retrieve your data. While there are many popular database options available, Redis (Remote Dictionary Server) offers a simple and lightweight solution for storing and manipulating your data.

In this tutorial, we will explore how to use Redis as a simple database for your Node.js Express.js web application.

Here is what we are implementing

graph TD
    Start[User Submits Form] -->|POST /save| A[Express Route Handler]
    A -->|Extract form data| B[username & email]
    B -->|client.set| C[Redis Database]
    C -->|Data stored| D[Success Redirect to Homepage]
    A -->|Error occurs| E[Handle Error and Send Error Message]

    StartView[User Requests Data] -->|GET /view/:username| F[Express Route Handler]
    F -->|Extract username param| G[username]
    G -->|client.get| C
    C -->|Data Retrieved| H[Render View with username & email]
    F -->|Error occurs| I[Handle Error and Send Error Message]

    Install[Install Dependencies] -->|npm install| Setup[Setup Node.js Express App]
    Setup -->|Install Redis Package| InstallRedis[Install redis npm package]
    InstallRedis -->|Connect to Redis| A

    style A fill:#FFC300,stroke:#333,stroke-width:2px,color:#000000
    style F fill:#FFC300,stroke:#333,stroke-width:2px,color:#000000
    style C fill:#66B2FF,stroke:#333,stroke-width:2px,color:#000000
    style D fill:#28A745,stroke:#333,stroke-width:2px,color:#000000
    style H fill:#28A745,stroke:#333,stroke-width:2px,color:#000000
    style E fill:#FF5733,stroke:#333,stroke-width:2px,color:#000000
    style I fill:#FF5733,stroke:#333,stroke-width:2px,color:#000000
    style Install fill:#DAA520,stroke:#333,stroke-width:2px,color:#000000
    style Setup fill:#DAA520,stroke:#333,stroke-width:2px,color:#000000
    style InstallRedis fill:#DAA520,stroke:#333,stroke-width:2px,color:#000000

Prerequisites

Before diving into this tutorial, make sure you have the following:

• A basic understanding of Node.js and Express.js
• Node.js and npm installed on your machine
• Redis installed and running on your machine (you can follow the instructions on redis.io to install Redis)

Setting up Redis in your Node.js Express.js Web App

To begin, let’s create a new Node.js Express.js web application using the express-generator package. Open your terminal and run the following command to install the package globally:

npm install -g express-generator

Next, create a new project with the express command:

express my-app-name

After the project has been generated, navigate into the project directory and install the dependencies by running the following commands:

cd my-app-name
npm install

Adding the redis Node.js package

Next, we need to install the redis npm package, which will enable us to connect to our Redis database from our Node.js application. From the terminal, run the following command:

npm install redis --save

Connecting to Redis

Now, let’s create a connection to our Redis server in our Node.js application. Open the app.js file and add the following lines at the top of the file, below the express import:

var redis = require('redis');
var client = redis.createClient();

This creates a new Redis client that we can use to communicate with our Redis server.

Handling Redis Errors

It’s good practice to handle any errors that might occur when connecting to our Redis server. To do this, we can use the client.on() method to listen for any error events, and console log the error if one occurs. Add the following code below the client declaration in the app.js file:

client.on("error", function(error) {
    console.log(error);
});

Saving Data to Redis

Now that we have our connection set up, we can start saving data to our Redis database. Let’s create a new route in our Node.js application that will get some data from a form submission, and save it to Redis.

In the routes/index.js file, add the following code to the bottom of the file:

router.post('/save', function(req, res, next) {
    // get the data from the form submission
    var username = req.body.username;
    var email = req.body.email;

    // save the data to Redis
    client.set(username, email, function(error, reply) {
        if (error) {
            console.log(error);
            res.send('Error occurred while saving data to Redis');
        } else {
            res.redirect('/');
        }
    });
});

This route will get the data from the form submission, and use the client.set() method to save the data to our Redis database. The client.set() method takes in three parameters: the key, the value, and a callback function that will be executed once the data has been saved. In this callback function, we can handle any errors that might occur, or redirect the user back to the homepage if the data was successfully saved.

Retrieving Data from Redis

Now that we have saved some data to our Redis database, let’s create another route that will retrieve the data and display it on a different page. In the routes/index.js file, add the following code to the bottom of the file:

router.get('/view/:username', function(req, res, next) {
    var username = req.params.username;

    // get the data from Redis
    client.get(username, function(error, reply) {
        if (error) {
            console.log(error);
            res.send('Error occurred while retrieving data from Redis');
        } else {
            res.render('view', {
                username: username,
                email: reply
            });
        }
    });
});

This route will use the client.get() method to get the data from Redis using the provided key. It then renders a view called view.ejs (which we will create in the next step) and passes in the username and email data as variables.

Creating the View

To display the retrieved data, let’s create a view called view.ejs. In the views directory, create a new file called view.ejs and add the following code:

<h2>View User</h2>
<p>Username: <%= username %></p>
<p>Email: <%= email %></p>

Testing the App

To test our app, start your Node.js server by running the following command from your terminal:

npm start

Then open http://localhost:3000 in your browser and submit some data using the form. You should see a success message and be redirected back to the homepage. Next, navigate to http://localhost:3000/view/username (replacing username with the username you submitted) and you should see the data displayed on the page.

Conclusion

In this tutorial, we explored how to use Redis as a simple database for our Node.js Express.js web applications. We learned how to connect to our Redis server, save and retrieve data, and handle any errors that might occur. Redis offers a lightweight and efficient solution for storing and manipulating data in your web application.