cf-workers-helmet

cf-workers-helmet is a wrapper for helmet to work with Cloudflare Workers. It provides important security headers to make your app more secure by default. cf-workers-helmet has been heavily inspired by koa-helmet.

Installation

npm install cf-workers-helmet --save

Usage

Usage is the same as helmet.

Helmet is a collection of 11 smaller middleware functions that set HTTP response headers.

Module	Default?
contentSecurityPolicy for setting Content Security Policy
crossdomain for handling Adobe products' crossdomain requests
dnsPrefetchControl controls browser DNS prefetching	✓
expectCt for handling Certificate Transparency
frameguard to prevent clickjacking	✓
hidePoweredBy to remove the X-Powered-By header	✓
hsts for HTTP Strict Transport Security	✓
ieNoOpen sets X-Download-Options for IE8+	✓
noSniff to keep clients from sniffing the MIME type	✓
referrerPolicy to hide the Referer header
xssFilter adds some small XSS protections	✓

You can see more in the documentation.

Example

import Helmet from 'cf-workers-helmet';
import {getAssetFromKV} from '@cloudflare/kv-asset-handler';

let helmet = new Helmet();

addEventListener('fetch', event => {
    event.respondWith(serverResponse(event));
});

async function serverResponse(event) {
    try {
        let response = await handleEvent(event);

        return helmet(event.request, response);
    } catch (e) {
        return new Response('Internal Error', {
            status: 500
        });
    }
}

async function handleEvent(event) {
    try {
        return await getAssetFromKV(event)
    } catch (e) {
        let pathname = new URL(event.request.url).pathname;

        return new Response(`"${pathname}" not found`, {
            status: 404,
            statusText: 'not found',
        });
    }
}