Loading and accessing certificates in node.js on Azure App Service

About

This how-to guide shows accessing private certificates/Public certificates in your node.js application running on Azure App Services.

Loading certificates

1. In the Azure portal, from the left menu, select App Services > app-name.

2. From the left navigation of your app, select TLS/SSL settings > Private key certificates (.pfx)/Public key certificates (.cer) > Upload Certificate.

   

3. Before we try to access the certificate through code we need to make the uploaded certificates accessible to the app service by adding WEBSITE_LOAD_CERTIFICATES app setting. This article outlines steps to Make the certificate accessible

Accessing the certificate through code

The below is the code where you can fetch the private/public certificates that you have uploaded in a programmatic manner using node.js on Windows App Service. We will be using NPM package ‘win-ca’ for simplicity.

const http = require('http');
const ca = require('win-ca');

// Create an instance of the http server to handle HTTP requests
let app = http.createServer((req, res) => {

// Set a response type of plain text for the response
res.writeHead(200, { 'Content-Type': 'text/plain' });

let certificates = []

// Fetch all certificates in PEM format from My store
ca({
    format: ca.der2.pem,
    store: ['My'],
    ondata: crt => certificates.push(crt)
})

// Send back a response and end the connection
  res.end("Certificate count under 'My' store is: " + certificates.length);
});

let port = process.env.PORT || 3000;

// Start the server on port 3000
app.listen(port);

You can refer the following documentation to access the thumbprint on Linux and Windows container App Services.