How to Create an HTTPS NodeJS Web Service with Express

When hosting NodeJS web applications with external APIs, it’s essential to keep communication secure. By setting up a popular NodeJS web framework called Express and configuring API endpoints to communicate via HTTPS NodeJS is a great way to do that.

In this tutorial, you will learn how to install and configure the Express NodeJS application framework and set up an encrypted API endpoint to keep communication encrypted.

Let’s get started!

Prerequisites

This tutorial is a hands-on demonstration. To follow along, be sure you have the following in place:

• A Linux machine – This tutorial will use Ubuntu 20.04.
• NodeJS – NodeJS acts as the runtime environment for all of your Express projects.

Creating a NodeJS Project

Once you have NodeJS installed on your server, it’s time to set up Express. The easiest way to install Express is via a NodeJS package. But before you do that, first create a directory for this demo project. This directory will be located in ~/NodejsHTTPSServer for this tutorial.

mkdir ~/NodejsHTTPSServer

Next, initialize a new NodeJS project using npm init. This command will create a package.json file in the directory you just created, recording necessary metadata about a project you are building.

Use the -y flag, as shown below to accept the default values. You do not need any unique NodeJS project settings for this tutorial. This action will create a NodeJS project with the same name as the folder (NodejsHTTPSServer).

npm init -y

Installing Express

Now it’s time to install the Express package. To do so, run the command below to install the NodeJS Express package. This command will install the NodeJS Express package save the information in the package.json file, as shown below.

npm install express

Creating a Web Service

It’s now time to create a web service/server with Express!

1. To get started, ensure you’re still in the ~/NodejsHTTPSServer directory and create a blank file called index.js. This file will be a Javascript script that will hold all necessary code that NodeJS will execute when launching the web service.

touch index.js

2. Next, open the index.js file and add the following code to it. This file leverages both built-in NodeJS modules and the installed express module to bring up a web service listening on port 4000 when executed.

// Import builtin NodeJS modules to instantiate the service
const https = require("https");
const fs = request("fs");

// Import the express module
const express = require("express");

// Instantiate an Express application
const app = express();

// Create a NodeJS HTTPS listener on port 4000 that points to the Express app
// Use a callback function to tell when the server is created.
https
  .createServer(app)
  .listen(4000, ()=>{
    console.log('server is runing at port 4000')
  });

// Create an try point route for the Express app listening on port 4000.
// This code tells the service to listed to any request coming to the / route.
// Once the request is received, it will display a message "Hello from express server."
app.get('/', (req,res)=>{
    res.send("Hello from express server.")
})

3. Once you’ve created the Express project, tell NodeJS to run it to bring up the web service.

node index.js

If successful, you will see the callback function defined above invoked to return a message letting you know it has started.

4. Finally, test the service by bringing up a web browser and navigating to http://localhost:4000/ in your browser. If successful, you should see a message “Hello from express server.”.

Creating an SSL Certificate

At this point, your NodeJS app doesn’t yet support HTTPS. It’s working with unencrypted HTTP, but that’s not secure. Let’s change that.

Related:Your Guide to X509 Certificates (For Mortals)

To configure an SSL certificate for our NodeJS HTTPS implementation, you can either use a public, trusted certificate or a self-signed certificate. This tutorial will use a self-signed certificate signed locally by the host as it’s much easier for proof of concept projects.

If you’re running a NodeJS HTTPS application with Express in a production environment, always be sure to acquire and install a trusted certificate!

Related:New-SelfSignedCertificate: Creating Certificates with PowerShell

1. First, generate a key file used for self-signed certificate generation with the command below. The command will create a private key as a file called key.pem.

openssl genrsa -out key.pem

2. Next, generate a certificate service request (CSR) with the command below. You’ll need a CSR to provide all of the input necessary to create the actual certificate.

openssl req -new -key key.pem -out csr.pem

3. Finally, generate your certificate by providing the private key created to sign it with the public key created in step two with an expiry date of 9,999 days. This command below will create a certificate called cert.pem.

openssl x509 -req -days 9999 -in csr.pem -signkey key.pem -out cert.pem

Once complete, your project folder should look like below:

NodejsHTTPSServer
	/cert.pem
	/csr.pem
	/index.js
	/key.pem
	/package-lock.json
	/package.json

Enabling HTTPS Nodejs in Express

At this point, your SSL certificate has been successfully created. Now it’s time to enable HTTPS with NodeJS and Express. To enable HTTPS requires slightly modifying the Express app you created earlier. Check this if you like to redirect your HTTP to HTTPS Traffic in NGINX.

Related:How to Redirect HTTP to HTTPS Traffic in NGINX

Open the index.js file you created earlier and modify the createServer() method, as shown below. You’ll notice that you must provide the private key (key.pem) and the public key/certificate (cert.pem) to the createServer() method.

The below example reads both private and public keys, which only execute once when the service starts.

https
  .createServer(
		// Provide the private and public key to the server by reading each
		// file's content with the readFileSync() method.
    {
      key: fs.readFileSync("key.pem"),
      cert: fs.readFileSync("cert.pem"),
    },
    app
  )
  .listen(4000, () => {
    console.log("serever is runing at port 4000");
  });

With that done, your express HTTPS server has been successfully created. Now test the application in your browser by going to https://localhost:4000.

You should still get the same response of “Hello from express server” on your browser.

Note that if you can’t initially browse to the web service with HTTPS, you may need to terminate and restart the server.

Conclusion

You should now understand how to set up a NodeJS HTTPS web service using the Express framework. By simply installing the Express NodeJS package and creating a simple configuration script, you can have a secure web service running over HTTPS.

How do you foresee using this web service script to host NodeJS HTTPS web services with Express?