Cloudflare Workers JWT Authentication Middleware

This example uses the itty-router package to add routing to the Cloudflare Worker.

auth.js is the file with the JWT validation code.

Using this code

You can use wrangler to generate a new Cloudflare Workers project based on the itty-router template by running the following command from your terminal:

wrangler generate myapp https://github.com/cloudflare/worker-template-router

Before publishing your code you need to edit wrangler.toml file and add your Cloudflare account_id - more information about configuring and publishing your code can be found in the documentation.

To add JWT authentication, add auth.js to your worker. Consider adding a ./src folder to your project, putting auth.js in that folder, and updating your import script in index.js to import auth from './src/auth.js',

When auth.js is added and imported, use it as middleware in private router calls by calling the function auth like so:

router.get("/private-route", auth, fooBar)

In the above example, .get can be replaced with any method like .post or even a catch-all method like .all. Also, fooBar is a placeholder function for your preferred function to handle the authenticated request.

Once you are ready, you can publish your code by running the following command:

wrangler publish

Worker Secrets Environment Variables

After publishing your Worker, for the middleware to work, you need to add the Wrangler Secrets to the Worker.

You need your JWT public RSA key. If you're using Auth0 you can download it from https://[your_domain].auth0.com/.well-known/jwks.json

You may have trouble adding large strings through console, and can add them in the Cloudflare Workers dashboard once your Worker is published.

You need the add the following four values: JWT_X5C, JWT_N, JWT_KID, JWT_X5T

Add them from the terminal like so:

wrangler secret put JWT_X5C

Then, at the prompt, paste the value and press enter.